Phosphorylation of BRAF by AMPK Attenuates MEK-ERK Signaling and Inhibits Keratinocyte Proliferation
The RAF-MEK-ERK signaling cascade plays a central role in transmitting mitogenic signals to regulate cell proliferation, survival, and differentiation. Among the RAF family kinases, BRAF is frequently mutated in human cancers, particularly melanoma, where the V600E mutation leads to constitutive activation of downstream MEK-ERK signaling. While BRAF inhibitors have shown remarkable clinical efficacy in treating BRAF-mutant melanomas, they paradoxically activate ERK signaling in cells with wild-type BRAF, contributing to the development of cutaneous squamous cell carcinomas (cSCC) in patients. This study identifies AMP-activated protein kinase (AMPK), a key cellular energy sensor, as a direct regulator of BRAF activity through phosphorylation at Ser729. Upon energy stress, AMPK is activated and phosphorylates BRAF at Ser729, which enhances its interaction with 14-3-3 adaptor proteins and disrupts its association with the scaffolding protein KSR1. This disruption impairs BRAF’s ability to form active complexes necessary for efficient MEK-ERK activation. As a result, AMPK-mediated phosphorylation significantly attenuates ERK signaling in keratinocytes and reduces cell proliferation. Importantly, this regulatory mechanism operates specifically in cells expressing wild-type BRAF, as BRAF V600E mutants fail to undergo this phosphorylation due to impaired AMPK activation in these cells. The findings reveal that AMPK functions as a metabolic brake on the RAF-MEK-ERK pathway, preventing excessive mitogenic signaling under low-energy conditions. Furthermore, pharmacological activation of AMPK using agents like phenformin or A-769662 effectively suppresses BRAF inhibitor-induced ERK hyperactivation and epidermal hyperplasia in mouse skin models. These results suggest that co-administration of AMPK activators with BRAF inhibitors may represent a promising strategy to mitigate the risk of cSCC development during targeted therapy. By linking cellular energy status to growth control, this mechanism provides insight into how metabolic stress can naturally limit proliferative responses, offering new avenues for therapeutic intervention in cancer and other proliferative disorders.
Activation of AMPK Suppresses RAF-MEK-ERK Signaling via BRAF Phosphorylation
AMPK serves as a master regulator of cellular energy homeostasis, becoming activated in response to metabolic stress such as glucose deprivation, hypoxia, or increased AMP/ADP levels. Once activated, AMPK orchestrates a broad reprogramming of metabolism to restore ATP balance by stimulating catabolic pathways and inhibiting anabolic processes. Beyond its metabolic roles, emerging evidence indicates that AMPK also regulates cell growth and proliferation. In this study, we demonstrate that AMPK directly modulates the RAF-MEK-ERK pathway by phosphorylating BRAF at Ser729.1,2-Bis(pyridin-4-ylmethylene)hydrazine Biological Activity Using multiple cell models—including CCD1106 keratinocytes, mouse embryonic fibroblasts (MEFs), and C140 melanocytes—we show that treatment with AMPK activators such as AICAR, phenformin, and A-769662 leads to a dose-dependent suppression of ERK phosphorylation. Notably, this effect is abolished in AMPK-null MEFs, confirming that AMPK is essential for this regulation. Mass spectrometry analysis of FLAG-tagged BRAF immunoprecipitated from Cos-7 cells revealed a significant increase in phosphorylation at Ser729 upon AICAR treatment, with minimal detection in untreated controls. Moreover, recombinant AMPK directly phosphorylated BRAF in vitro, and mutation of Ser729 to alanine abrogated this phosphorylation. An antibody specific for pSer729 BRAF confirmed robust phosphorylation in response to AMPK activation in both human keratinocytes and MEFs. These data collectively establish that AMPK is the long-sought kinase responsible for phosphorylating BRAF at Ser729 in vivo. The phosphorylation site lies within a sequence motif consistent with AMPK substrate specificity, further supporting its direct targeting. This finding reveals a previously unknown layer of regulation in the RAF-MEK-ERK cascade, where energy-sensing mechanisms directly influence oncogenic signaling pathways.
AMPK-Mediated Phosphorylation of BRAF Disrupts Scaffolding Complexes and Limits Cell Growth
Upon phosphorylation at Ser729, BRAF exhibits enhanced binding to 14-3-3 proteins, which are critical signaling adaptors involved in subcellular localization and functional modulation of their clients. Our immunoprecipitation experiments demonstrated that AICAR treatment promotes the association between endogenous BRAF and 14-3-3 in wild-type MEFs but not in AMPK-null cells. Similarly, GST-14-3-3 pull-down assays confirmed this interaction in CCD1106 keratinocytes. Importantly, this phosphorylation event selectively disrupts the interaction between BRAF and the scaffold protein KSR1, which is essential for efficient MEK activation. Co-immunoprecipitation studies showed reduced BRAF-KSR1 complex formation following AMPK activation, and this effect was lost when Ser729 was mutated to alanine. Interestingly, while AMPK activation also disrupted BRAF-CRAF heterodimerization, the S729A mutant failed to bind CRAF regardless of AMPK status, suggesting that the hydroxyl group of Ser729 contributes to dimer stability even in the absence of 14-3-3 binding. We further found that high-affinity 14-3-3 binding requires phosphorylation of both Ser729 and Ser365, another known 14-3-3 docking site. Mutation of either site impairs 14-3-3 association and allows sustained ERK activation despite AMPK stimulation. These findings support a model in which AMPK phosphorylation of BRAF induces a conformational change that promotes 14-3-3 binding and sterically hinders interactions with KSR1 and CRAF, thereby dampening the overall signaling output. This mechanism ensures that mitogenic signaling is restrained under energy-deficient conditions, preserving cellular resources for essential survival functions.
AMPK Activation Inhibits Keratinocyte Proliferation and Prevents Skin Hyperplasia Induced by BRAF Inhibitors
Given the central role of RAF-MEK-ERK signaling in driving cell cycle progression and proliferation, we investigated whether AMPK-mediated BRAF phosphorylation affects cellular growth. Stable expression of BRAF S729A mutant in CCD1106 keratinocytes resulted in significantly higher proliferation rates compared to cells expressing wild-type BRAF, indicating that Ser729 phosphorylation acts as a negative regulator of cell growth. Flow cytometry analysis revealed that AICAR treatment induced G2/M phase arrest and S-phase accumulation in wild-type BRAF-expressing cells, whereas the S729A mutant cells were largely resistant to these effects.Alclometasone dipropionate (Standard) Data Sheet Consistent with this, AICAR exerted a stronger inhibitory effect on proliferation in WT BRAF cells than in S729A-expressing cells.PMID:33797671 These results confirm that AMPK-dependent phosphorylation of BRAF at Ser729 plays a crucial role in regulating the cell cycle and proliferation in keratinocytes. More importantly, we tested whether AMPK activation could counteract the adverse effects of BRAF inhibitors. In mouse skin, administration of PLX4720 led to significant epidermal hyperplasia and increased Ki67 staining, indicative of hyperproliferation. However, co-treatment with the AMPK activator phenformin markedly reduced both epidermal thickness and proliferation index. Immunohistochemistry confirmed that phenformin prevented PLX4720-induced phosphorylation of ERK and upregulation of Ki67. Similar protective effects were observed with A-769662. These findings demonstrate that AMPK activation can effectively antagonize the paradoxical activation of ERK signaling caused by BRAF inhibitors in normal tissues, thereby preventing the development of cSCC-like lesions. This highlights the therapeutic potential of combining AMPK activators with BRAF-targeted therapies to improve safety profiles without compromising anti-tumor efficacy.
Mechanistic Insights into AMPK Regulation of BRAF and Implications for Cancer Therapy
This study uncovers a fundamental mechanism by which cellular energy status governs oncogenic signaling through direct post-translational modification of BRAF. The identification of AMPK as the kinase responsible for phosphorylating BRAF at Ser729 resolves a longstanding question about the regulation of this key residue. Unlike other kinases that modulate BRAF activity through feedback loops or allosteric regulation, AMPK acts as a primary controller that integrates metabolic cues into growth decisions. By promoting 14-3-3 binding and disrupting critical scaffolding interactions, AMPK effectively silences BRAF signaling under conditions of energy stress, acting as a physiological safeguard against uncontrolled proliferation. The differential sensitivity of BRAF V600E mutants to this regulation underscores a key vulnerability: these tumors are defective in AMPK activation due to ERK-mediated inhibition of upstream kinases like LKB1, rendering them insensitive to this metabolic checkpoint. This explains why BRAF inhibitors trigger side effects only in normal tissues—where wild-type BRAF remains responsive to AMPK regulation—while failing to affect the tumor itself. Therefore, targeting AMPK in non-cancerous tissues offers a rational approach to prevent drug-induced toxicities. Future therapeutic strategies may involve the use of safe, bioavailable AMPK activators such as phenformin or metformin as adjuncts to BRAF inhibitors. Such combinations could maintain anti-tumor efficacy while minimizing risks of secondary malignancies, representing a major advancement in precision oncology.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com
**Background**
Cancer and viral infections remain significant global health challenges, necessitating the discovery of multi-target therapeutic agents. In particular, the inhibition of angiogenesis and the induction of apoptosis are critical strategies for suppressing tumor growth and metastasis. Furthermore, the management of chronic inflammation and viral replication requires compounds that can modulate key signaling pathways and enzymatic activities. Flavonoids, naturally occurring polyphenolic compounds, have gained attention for their diverse pharmacological properties, including anti-inflammatory and antitumor activities. In this context, we will introduce a potent flavonoid isolated from hops – Xanthohumol.
**Definition**
Xanthohumol is a principal flavonoid that acts as an inhibitor of diacylglycerol acetyltransferase (DGAT), COX-1, and COX-2. According to the Xanthohumol description, it exhibits significant anti-cancer, anti-angiogenic, and antiviral activities.
**In Vitro Studies**
The Xanthohumol biological activity has been extensively documented across various cell lines and physiological systems. In terms of cardiovascular and hematological effects, Xanthohumol significantly attenuates ADP-induced blood platelet aggregation and reduces the expression of the activated fibrinogen receptor (GPIIbIIIa) on platelet surfaces. In rat ventricular myocytes, concentrations of 5-50 nM reduce the frequency of spontaneously occurring Ca2+ sparks and waves, while 50-100 nM reduces the rate of relaxation of Ca2+ transients and suppresses SR Ca2+ content.
Regarding Xanthohumol Cancer research, the compound demonstrates potent cytotoxicity and antiproliferative effects. In glioma cells, it induces apoptosis via pro-caspase-3/8 cleavage, PARP degradation, and mitochondrial dysfunction, specifically inhibiting the IGFBP2/AKT/Bcl2 pathway through miR-204-3p targeting. In endothelial cells, it activates AMPK via CAMMKβ (but not LKB1), which subsequently reduces nitric oxide (NO) levels by decreasing eNOS phosphorylation, thereby mediating its anti-angiogenic activity. Additionally, the AKT pathway is inactivated independently of AMPK.
Xanthohumol in vitro data shows varying IC50 values across multiple human cell lines: it exhibits cytotoxicity against Ishikawa cells (IC50 = 4.2 μM), BGC-823 cells (IC50 = 7.8 μM), and MCF7 cells (IC50 = 3.47 μM after 4 days). It also shows antiproliferative activity against A549 cells (IC50 = 11.9 μM), HeLa cells (IC50 = 9.4 μM), and NCI-H460 cells (IC50 = 6.9 μM). Furthermore, it demonstrates antiviral activity against bovine viral diarrhea virus (BVDV), rhinovirus, HSV-1, HSV-2, and cytomegalovirus (CMV). In conclusion, Xanthohumol is a multi-functional flavonoid with broad applications in oncology, virology, and cardiovascular research.
Keywords
Xanthohumol, 6754-58-1, COX, Acyltransferase, Apoptosis, HSV, CMV, Influenza Virus, Cyclooxygenase, Diacylglycerol acyltransferase, Diglyceride acyltransferase, acyl-CoA:cholesterol acyltransferase, mono- acylglycerol acyltransferase, Herpes simplex virus, Cytomegalovirus
References
[1] Luzak B, et al. Xanthohumol from hop cones (Humulus lupulus L.) prevents ADP-induced platelet reactivity. Arch Physiol Biochem. 2016 Nov 18:1-7
[2] Arnaiz-Cot JJ, et al. Xanthohumol modulates calcium signaling in rat ventricular myocytes: Possible Antiarrhythmic properties. J Pharmacol Exp Ther. 2016 Nov 4. pii: jpet.116.236588
[3] Gallo C, et al. Hop derived flavonoid xanthohumol inhibits endothelial cell functions via AMPK activation. Oncotarget. 2016 Aug 1
[4] Chen PH, et al. The miR-204-3p-targeted IGFBP2 pathway is involved in xanthohumol-induced glioma cell apoptotic death. Neuropharmacology. 2016 Nov;110(Pt A):362-75.
[5] Buckwold VE, et al. Antiviral activity of hop constituents against a series of DNA and RNA viruses. Antiviral Res. 2004 Jan;61(1):57-62.
[6] Inokoshi J, et al. Expression of two human acyl-CoA:diacylglycerol acyltransferase isozymes in yeast and selectivity of microbial inhibitors toward the isozymes. J Antibiot (Tokyo). 2009;62(1):51-54.
The SNARE complex plays a central role in synaptic vesicle fusion, forming a four-helix bundle between synaptobrevin on the vesicle membrane and syntaxin and SNAP25 on the plasma membrane. This assembly drives membrane fusion and neurotransmitter release. Complexin (Cpx), a small cytosolic protein, binds to the SNARE complex and functions as a fusion clamp, preventing spontaneous fusion while facilitating evoked release. Despite extensive research, the precise molecular mechanism by which Cpx clamps fusion remains unclear. In this study, we employed molecular dynamics (MD) simulations to investigate the interaction between the Cpx accessory helix (AH) and the C-terminus of the SNARE complex, aiming to elucidate how Cpx stabilizes a partially unzipped state that acts as a fusion clamp.
We began by constructing an initial model of the SNARE/Cpx complex using high-resolution X-ray structures: 1N7S for the SNARE complex and 1KIL for the SNARE/Cpx complex. The initial topology was optimized using Monte-Carlo minimization (MCM) with the ZMM/MVM software package. Subsequent MD simulations were performed using NAMD and VMD, employing the CHARMM22 force field with CMAP correction. A water box with KCl at 150 mM concentration was used to mimic physiological conditions. Simulations were conducted under periodic boundary conditions with Ewald electrostatics and Langevin thermostat at 300 K.
Our results revealed that in a solvated environment, the Cpx AH forms tight, stable interactions with both synaptobrevin (Syb) and the C-terminal domain of SNAP25 (SN2). These interactions are stabilized by salt bridges and hydrophobic contacts, particularly involving residues K37 and L41 of Cpx. Over a 250 ns simulation, the Cpx AH transitioned from transient contact with Syb to a stable position within the groove between Syb and SN2, where it remained for the duration of the simulation despite brief disruptions of individual salt bridges.
To assess the impact of membrane repulsion on SNARE stability, we calculated the electrostatic repulsive force between the vesicle and plasma membranes. Using the Debye-Hückel approximation, we estimated forces ranging from 93 pN (fixed potential) to 210 pN (fixed charge), depending on assumptions about surface charge regulation. Applying an external force of 140 pN (2 kcal/mol/Å) to the C-terminal residue of Syb (W89) induced rapid separation of layers 8 and partial disruption of layer 7, but not layer 6. The energy barrier for unzipping was modest, suggesting that such a partially unzipped state is energetically accessible. However, further unzipping beyond layer 7 required significantly higher forces, which are unlikely to be generated by membrane repulsion alone due to its steep distance dependence.
When Cpx was present, the partially unzipped state became more stable.Pyridostigmine medchemexpress Relaxation simulations showed that in the presence of Cpx, the SNARE complex maintained a separated conformation with layers 7 and 8 unzipped, and the energy declined consistently below baseline.DOTAP NF-κB In contrast, without Cpx, the complex tended to rezip.PMID:34972260 This indicates that Cpx stabilizes a metastable, partially unzipped state—consistent with a fusion clamp.
We tested this model using the Drosophila syx3-69 mutant, which exhibits enhanced spontaneous release resembling the cpx null phenotype. The T251I mutation in syntaxin alters the local structure of layer 7, disrupting the interaction between the Cpx AH and Syb. MD simulations confirmed that this mutation shifts Cpx’s orientation toward SN2, weakening its binding to Syb. Experimentally, focal recordings from neuromuscular junctions showed increased spontaneous release in syx3-69, though less severe than in cpx null mutants—supporting a partial loss-of-function phenotype.
In conclusion, our computational and experimental data support a model in which the Cpx AH clamps fusion by binding to the C-terminus of Syb, stabilizing a partially unzipped SNARE complex. This prevents full zippering and maintains the vesicle at a distance (~5 nm) where fusion cannot occur. The model explains both the clamping function of Cpx and the phenotypic effects of mutations like syx3-69, providing a mechanistically coherent and energetically favorable explanation for synaptic fusion control.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com
**Background**
Chronic cough is a debilitating condition that significantly impacts the quality of life for patients, often resulting from prolonged airway inflammation or hypersensitivity of the sensory nerves. The pathogenesis of this condition is closely linked to the activation of nociceptors, which are specialized sensory neurons that respond to noxious stimuli. When these nociceptors enter an activated or inflammatory state, they can trigger an exaggerated cough reflex. Sodium channels play a critical role in the initiation and propagation of action potentials in these neurons, making them prime targets for therapeutic intervention. By selectively modulating these channels, it is possible to reduce the hypersensitivity of the cough reflex without affecting normal physiological functions. In this context, we will introduce a sodium channel blocker – Taplucainium.
**Definition**
Taplucainium chloride is a sodium channel blocker designed to selectively inhibit nociceptors that are in an activated or inflammatory state. According to the Taplucainium description, this compound is utilized primarily in the research of chronic cough and related sensory neuropathies.
**In Vitro Studies**
The Taplucainium biological activity is characterized by its ability to target specific states of neuronal activation. Taplucainium In Vitro studies have demonstrated that the compound selectively inhibits nociceptors when they are in an inflammatory or activated state, thereby preventing the over-firing of sensory neurons associated with the cough reflex. This selectivity is crucial for minimizing off-target effects on healthy tissues. For researchers seeking detailed specifications, the Taplucainium technical information provides the molecular weight of 386.96 and the Taplucainium Formula as C23H31ClN2O. In conclusion, Taplucainium is a selective sodium channel blocker that holds promise as a tool for studying and treating chronic cough.
Keywords
Taplucainium, 2489565-37-7, Sodium Channel, Na channels, Na+ channels, Inhibitor, inhibitor, inhibit
References
[1] Elizabeth STEPHAN, et al. Compositions and methods for treating chronic cough. 2025-12-11
Chronic kidney disease (CKD) is a major global health issue characterized by progressive loss of renal function and structural damage. One of the key contributors to CKD progression is metabolic acidosis, which arises due to impaired acid excretion and reduced bicarbonate levels. This condition not only exacerbates renal injury but also accelerates glomerulosclerosis and tubulointerstitial fibrosis. Alkali therapy, particularly through sodium bicarbonate supplementation, has emerged as a promising intervention to slow CKD progression. In this study, we investigated the effects of dietary sodium bicarbonate on kidney function and pathology in a 5/6 nephrectomized rat model—a well-established experimental system for chronic renal failure.
Male Sprague-Dawley rats underwent partial nephrectomy to induce remnant kidney disease. Following surgery, animals were divided into two groups: one received a diet supplemented with sodium bicarbonate (NaHCO₃), while the other received an equivalent amount of sodium chloride (NaCl). Both diets contained 20% casein to standardize protein intake. Over a 10-week period, serum bicarbonate levels significantly increased in the NaHCO₃ group compared to controls, indicating effective correction of metabolic acidosis. Glomerular filtration rate (GFR), calculated from urea and creatinine clearance, was markedly higher in the alkali-treated group at both week 4 and week 10. Notably, GFR remained stable in the NaHCO₃ group, whereas it declined progressively in the NaCl group, suggesting that alkali therapy preserved renal function.
Histopathological analysis revealed significant protection against structural damage in the NaHCO₃ group. The glomerulosclerosis index was significantly lower at weeks 4 (0.17 ± 0.04 vs. 0.47 ± 0.06, P < 0.001) and 10 (0.66 ± 0.06 vs. 0.99 ± 0.07, P = 0.001). Similarly, tubulointerstitial (TI) lesion indices were reduced—by approximately half at week 4 (0.45 ± 0.01 vs. 0.92 ± 0.12, P = 0.004) and by three-quarters at week 10 (1.33 ± 0.12 vs. 1.80 ± 0.12, P = 0.010). These findings demonstrate that alkali therapy attenuates both glomerular and interstitial injury. At the molecular level, immunoblotting and immunohistochemistry showed that expression of the apical Na⁺/H⁺ exchanger type 3 (NHE3) was significantly downregulated in the NaHCO₃ group at week 4 (10.1 ± 4.25 vs. 100 ± 21.1, P = 0.007), with a trend toward reduction at week 10.Simvastatin Ferroptosis Apical NHE3 reactivity was also diminished, indicating functional suppression.4-(1H-Pyrazol-4-yl)pyridine Technical Information Moreover, endothelin-1 (ET-1) levels in kidney tissue were significantly lower in the NaHCO₃ group at week 10 (0.PMID:35161821 32 ± 0.15 vs. 1.14 ± 0.20 pg/mL/mg protein, P = 0.021), suggesting reduced vasoconstrictive and pro-fibrotic signaling. Expression of other transporters such as NKCC2, NBC, pendrin, and H⁺-ATPase remained unchanged, highlighting the specificity of NHE3 modulation.
These results indicate that alkali therapy ameliorates CKD progression primarily through inhibition of NHE3 activity and suppression of ET-1. By reducing intracellular sodium and hydrogen ion accumulation, alkali therapy may alleviate cellular stress, inflammation, and fibrogenic pathways in the remaining kidney. Thus, targeting NHE3 represents a potential therapeutic strategy for slowing renal decline in chronic kidney disease.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com
Spontaneous preterm birth remains the leading cause of neonatal mortality and long-term neurological disabilities among survivors. A significant proportion of these cases are linked to intrauterine infection, which triggers a robust inflammatory response. This cascade activates multiple pathways culminating in myometrial contractions and rupture of fetal membranes—key events in labor initiation. In non-gestational tissues, the citrus flavone nobiletin has demonstrated potent anti-inflammatory effects. This study aimed to evaluate whether nobiletin could modulate pro-inflammatory and pro-labour mediators in human fetal membranes and myometrium exposed to bacterial endotoxin lipopolysaccharide (LPS). Additionally, its effects were assessed in fetal membranes obtained from women who experienced spontaneous preterm birth with or without histological chorioamnionitis.
Human fetal membranes and myometrial tissues were treated with LPS in the presence or absence of nobiletin. In both tissue types, nobiletin significantly suppressed LPS-induced expression of key pro-inflammatory cytokines—TNF-α, IL-1β, IL-6, and IL-8—as well as matrix metalloproteinase-9 (MMP-9) mRNA levels and secreted pro-MMP-9. Furthermore, nobiletin markedly reduced COX-2 expression and subsequent prostaglandin E₂ (PGE₂) production in myometrial tissues.Tolvaptan References Notably, nobiletin also attenuated the expression and secretion of these inflammatory markers in fetal membranes isolated from spontaneous preterm deliveries, regardless of infection status.4-Methylphthalic anhydride medchemexpress These findings indicate that nobiletin effectively dampens infection-driven inflammation in gestational tissues.PMID:35073864
The results support the growing body of evidence linking high fruit and vegetable intake during pregnancy with reduced risk of adverse outcomes. Given its superior bioavailability compared to other phytophenols, nobiletin represents a promising dietary compound with potential therapeutic value in preventing or delaying preterm birth. By targeting multiple inflammatory pathways central to labor initiation, nobiletin may serve as a safe and effective agent to mitigate the risks associated with premature delivery.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com
**Background**
Cystic fibrosis (CF) is a severe genetic disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The CFTR protein functions as a chloride channel across the epithelial cell membranes of various organs, including the lungs and pancreas. When the CFTR protein is dysfunctional or absent, it leads to the production of thick, sticky mucus, resulting in chronic pulmonary infections, progressive lung damage, and multi-organ failure. Developing small molecules that can correct the folding of the CFTR protein or potentiate its gating activity is a critical strategy for treating this disease. In this context, we will introduce a CFTR modulator – Olacaftor.
**Definition**
Olacaftor (VX-440) is a cystic fibrosis transmembrane conductance regulator (CFTR) modulator. According to the Olacaftor description, this compound is designed to improve the function of the CFTR protein to alleviate the symptoms associated with cystic fibrosis.
**Mechanism of Action**
Olacaftor acts as a modulator of the CFTR channel, aiming to restore the transport of chloride ions across the cell membrane. By improving the stability and gating of the CFTR protein, it helps normalize the viscosity of mucus in the respiratory tract. Researchers seeking detailed Olacaftor technical information can refer to its chemical properties, including its molecular weight of 539.66 and its Olacaftor Formula, $\text{C}_{29}\text{H}_{34}\text{FN}_3\text{O}_4\text{S}$.
**Experimental Studies**
The Olacaftor biological activity has been characterized through extensive pharmacological evaluations. As detailed in the Olacaftor References, the compound was developed to target specific CFTR mutations to enhance protein trafficking and function. While specific IC50 values and detailed cell line concentrations are typically proprietary or specified in the patent documentation, the compound has been validated for its ability to modulate the CFTR protein. In conclusion, Olacaftor is a potent CFTR modulator that holds significant potential for the treatment of cystic fibrosis.
Keywords
Olacaftor, 1897384-89-2, VX-440, VX440, VX 440, CFTR, Autophagy, Cystic fibrosis transmembrane conductance regulator, Inhibitor, inhibitor, inhibit
References
[1] Miller M, et al. Modulators of cystic fibrosis transmembrane conductance regulator. US9782408.
A 51-year-old woman was diagnosed with essential thrombocythemia (ET) in 1995, presenting with a markedly elevated platelet count of 1240 × 10⁹/L and hypercellular bone marrow dominated by large, mature megakaryocytes. Over the next 16 years, she remained stable on anti-thrombotic therapy, with no evidence of thrombosis or progression to myelofibrosis. In October 2011, at age 67, she presented with progressive cytopenia and an abrupt decline in platelets to 336 × 10⁹/L, accompanied by 14% blasts in peripheral blood. Bone marrow examination revealed hypercellularity with 76% leukemic blasts and increased megakaryocytes. Immunophenotyping confirmed a B-cell lineage phenotype (CD34+ CD19+ CD10+ HLA-DR+), and molecular analysis demonstrated monoclonal immunoglobulin heavy chain rearrangement. Cytogenetic and FISH studies identified the Philadelphia chromosome translocation t(9;22)(q34;q11.2) and monosomy 7. RT-PCR detected the minor BCR-ABL1 fusion transcript, confirming the diagnosis of Ph+ALL.
To determine clonal origins, mutational analysis was performed on granulocytes, lineage-negative CD34+ hematopoietic stem and progenitor cells (HSPCs), and CD34+CD19+ B-ALL cells.6-(4-Hydroxyphenoxy)hexyl custom synthesis JAK2-V617F mutation was present in granulocytes and HSPCs but absent in the B-ALL population, indicating that the Ph+ALL clone did not originate from the JAK2-mutated ET clone.Arterolane Activator Further investigation into the timing of BCR-ABL1 acquisition revealed that the minor transcript was detectable not only in committed B-cell precursors (CD34+CD19+CD10+) but also in the CD34+CD19−CD10− HSPC-enriched population, suggesting early acquisition prior to B-cell commitment.PMID:35228900 FISH confirmed the presence of the Philadelphia chromosome in 54% of CD34+CD19−CD10− cells and 10% of granulocytes.
The patient was treated with dasatinib and prednisolone. Four weeks later, blast counts declined significantly. However, RT-PCR analysis of sorted bone marrow subpopulations showed rapid disappearance of the minor BCR-ABL1 transcript in CD34+CD19− cells—likely representing primitive HSPCs—but persistence in CD34+CD19+ cells. Despite this, the transcript remained detectable at low levels in bulk bone marrow after ten weeks. Nine months post-treatment initiation, relapse occurred with the emergence of the T315I mutation, indicating selection of a resistant clone within the committed B-cell compartment rather than from the most primitive stem cells.
This case highlights the complexity of clonal evolution in MPN-associated leukemias. The absence of JAK2-V617F in Ph+ALL cells demonstrates that transformation to lymphoid leukemia can occur independently of the MPN clone. Moreover, the persistence of BCR-ABL1 in committed B-cells despite clearance in HSPCs challenges the assumption that resistance arises solely from quiescent stem cells. These findings suggest that the resistant clone may reside in differentiated populations, possibly due to microenvironmental protection or intrinsic resistance mechanisms. This observation bridges gaps between murine models and human disease, underscoring the need for deeper investigation into the biology of resistant clones in Ph+ALL patients undergoing TKI therapy.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com
Natural antisense transcripts (NATs) represent a significant class of regulatory RNAs that exhibit sequence complementarity to other transcripts. These molecules are increasingly recognized for their roles in post-transcriptional gene regulation across eukaryotes, including plants. In soybean (Glycine max), NATs have been predicted in the PlantNATsDB, yet comprehensive functional and structural analyses remain limited. This study presents a large-scale prediction and experimental validation of NATs in soybean, integrating high-throughput sequencing data from small RNAs and degradome profiles. A total of 26,216 NATs were identified, comprising 994 cis-NATs and 25,222 trans-NATs. Each sense transcript was found to associate with between one and 177 antisense transcripts, highlighting the complexity of NAT interactions. RT-PCR amplification confirmed the expression of 21 trans-NATs, providing direct evidence of their biological relevance.
Further analysis revealed that 179 cis-NATs and 6,629 trans-NATs produce small RNAs, predominantly enriched within overlapping regions. The most abundant small RNA species were 21, 22, and 24 nucleotides in length—consistent with typical sizes of natural antisense siRNAs (nat-siRNAs). The generation of these small RNAs showed a strong bias toward one strand of the NAT duplex, suggesting directional processing by Dicer-like enzymes. Degradome sequencing enabled global identification of nat-siRNA targets, revealing 446 target genes associated with 165 distinct nat-siRNAs. Notably, these targets included not only the sense or antisense strands of the originating NAT but also unrelated transcripts, indicating broad regulatory potential. Five NAT transcripts were found to form stem-loop structures characteristic of pre-microRNAs, suggesting dual functionality in both miRNA and nat-siRNA biogenesis. Additionally, 86 known miRNA targets were identified as having antisense transcripts, implying cross-talk between miRNA and NAT pathways.5-TAMRA Cadaverine In stock
These findings collectively demonstrate that NATs in soybean function within intricate regulatory networks involving small RNAs, transcriptional interference, and post-transcriptional silencing.N-Boc-7-aminoheptanoic acid medchemexpress The interplay among cis- and trans-NATs, nat-siRNAs, miRNAs, and their respective targets suggests a highly coordinated system influencing gene expression during development and stress responses.PMID:35247502 This work provides a foundational resource for understanding the regulatory landscape of soybean, offering insights into how non-coding RNAs shape genome activity and adaptation.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com
**Background**
Heat shock protein 90 (Hsp90) is a highly conserved molecular chaperone that plays a critical role in maintaining the stability and function of numerous client proteins, many of which are oncogenic kinases and transcription factors. Due to its ability to facilitate the folding and maturation of proteins essential for cell survival and proliferation, Hsp90 is frequently overexpressed in various malignancies. Inhibiting Hsp90 leads to the degradation of these client proteins, thereby suppressing tumor growth and inducing apoptosis. Consequently, Hsp90 has become a primary therapeutic target in the development of anticancer strategies. In this context, we will introduce an Hsp90 C-terminal inhibitor – HSP90-IN-22.
**Definition**
HSP90-IN-22 (Compound 35) is a potent Hsp90 inhibitor that exhibits significant antiproliferative properties against human breast cancer cell lines.
**In Vitro Studies**
Regarding the HSP90-IN-22 description, this compound is a 6-acylamino-2-aminoquinoline derivative with a molecular weight of 434.53 and the chemical formula C25H30N4O3. In terms of HSP90-IN-22 biological activity, the compound has been evaluated for its cytotoxicity using MTT assays. In vitro studies demonstrated that HSP90-IN-22 possesses potent antiproliferative activity against human breast cancer cells after 72 hours of incubation. Specifically, it exhibited IC50 values of 3.65 μM for MCF7 breast cancer cells and 2.71 μM for SKBr3 breast cancer cells. These results indicate that the compound effectively inhibits the proliferation of different breast cancer subtypes by targeting the Hsp90 pathway. In conclusion, HSP90-IN-22 is a novel Hsp90 C-terminal inhibitor with promising potential for breast cancer research.
Keywords
HSP90-IN-22, 442898-75-1, HSP, Heat shock proteins, MCF7 cells, SKBr3 cells, antiproliferative, Hsp90, Inhibitor, inhibitor, inhibit
References