Search Results (414)

Melanoma is one of the most invasive skin cancers with the highest mortality risk. The PI3K/AKT/mTOR signaling pathways are a key regulatory point related to growth factors and involved in the cell’s energy metabolism. They are responsible for cell life processes such as growth, proliferation, invasion, survival, apoptosis, autophagy, and angiogenesis. The studies undertaken concerned the effect of protein kinase inhibitors involved in the signaling pathways of AKT, MEK, and mTOR kinases on the expression of cytoskeletal and extracellular matrix proteins, invasion process, and activities of the matrix metalloproteinases (MMPs): MMP-2 and MMP-9 in melanoma cells. The study used mTOR kinase inhibitors: Everolimus and Torkinib; dual PI3K/mTOR inhibitors BEZ-235 and Omipalisib; and the mTORC1/2 inhibitor OSI-027. These compounds were used both as monotherapy and in combination with the MEK1/2 inhibitor AS-703026. mTOR kinase inhibitors, especially the third generation in combination with the MEK 1/2 kinase inhibitor AS-703026, significantly inhibited invasion and metalloproteinases (MMPs) activity in melanoma cell lines. The inhibition of the cell invasion process was accompanied by a significant change in the expression of proteins associated with EMT. The morphology of cells also changed significantly: their thickness, volume, roughness, convexity of shape, and irregularity, which may be a good diagnostic and prognostic factor for the response to treatment. Our studies to date on the effect of three generations of mTOR kinase inhibitors on the inhibition of the invasion process, the activation of apoptosis, and the reduction in cell proliferation suggest that they may be an important target for anticancer therapy. Full article

Background: Esophageal cancer (EC), including esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma (ESCC), remains a lethal malignancy with limited molecularly tailored treatment options. Due to substantial histologic and transcriptomic differences between subtypes, therapeutic responses often vary, underscoring the need for subtype-stratified analysis and precision drug discovery. Methods: We integrated transcriptomic data from GEO and TCGA to identify differentially expressed genes (DEGs) specific to EAC, ESCC, and their shared profiles. Functional enrichment (GO, KEGG) and protein–protein interaction (PPI) network analyses were conducted to extract hub genes using DAVID, STRING, and Cytoscape. Survival associations were evaluated using TCGA-ESCA and UALCAN. Drug repurposing was performed using L1000FWD, L1000CDS2, and SigCom LINCS. Results: We identified 79, 59, and 17 hub genes in the DEG-EAC, DEG-ESCC, and DEG-EAC&ESCC datasets, respectively. In EAC, 16 novel hub genes including SCARB1, SERPINH1, and DSC2 were discovered, which had not been previously implicated in this subtype. These genes were significantly enriched in pathways related to extracellular matrix (ECM) remodeling and epithelial structure. In addition, shared hub genes across EAC and ESCC—such as COL1A1, SPARC, and MMP1—were enriched in ECM organization and cell adhesion processes, highlighting convergent tumor–stroma interactions. Drug repositioning analysis consistently prioritized MEK inhibitors, trametinib and selumetinib, as potential therapeutic candidates across all DEG datasets. Conclusions: This study presents a comprehensive, subtype-stratified transcriptomic framework for EC, identifying both unique and shared hub genes with potential functional relevance to ECM dynamics. Our findings suggest that ECM remodelers may serve as therapeutic targets, and highlight MEK inhibition as a promising, yet exploratory, repurposing strategy. While these results offer a molecular foundation for future precision oncology efforts in EC, further validation through proteomic analysis, functional studies, and clinical evaluation is warranted. Full article

Gain-of-function gene alterations in rearranged during transfection (RET), a receptor tyrosine kinase, are observed in both sporadic and hereditary medullary thyroid cancers (MTCs) and pheochromocytomas and paragangliomas (PPGLs). Several tyrosine kinase inhibitors (TKIs) that target RET have been proven to be effective on MTCs and PCCs. Recently, TKIs, namely, sunitinib and selpercatinib, which were clinically used to target PPGLs, have been reported to decrease catecholamine levels without reducing tumor size. Our clinical case of metastatic medullary thyroid cancer, which is associated with RET mutations undergoing treatment with vandetanib, also suggests that vandetanib can decrease catecholamine levels. Therefore, we investigated the effect of vandetanib, a representative multi-targeted TKI for RET-related MTC, on cell proliferation and catecholamine synthesis in rat pheochromocytoma PC12 cells. Vandetanib reduced viable cells in a concentration-dependent manner. The dopamine and noradrenaline levels of the cell lysate were reduced in a concentration-dependent manner. They also decreased more prominently at lower concentrations of vandetanib compared to the inhibition of cell proliferation. The RNA knockdown study of Ret revealed that this inhibitory effect on catecholamine synthesis is mainly mediated by the suppression of RET signaling. Next, we focused on two signaling pathways downstream of RET, namely, ERK and AKT signaling. Treatment with vandetanib reduced both ERK and AKT phosphorylation in PC12 cells. Moreover, both an MEK inhibitor U0126 and a PI3K/AKT inhibitor LY294002 suppressed catecholamine synthesis without decreasing viable cells. This study in rat pheochromocytoma PC12 cells reveals the direct inhibitory effects of vandetanib on catecholamine synthesis via the suppression of RET-ERK and RET-AKT signaling. Full article

The Mitogen-activated protein kinase kinase (MEK) protein family has dual-specificity protein kinases with a myriad of cellular functions that include but are not limited to cell survival, cell division, immunologic response, angiogenesis, and cellular senescence. MEK is crucial in the MAPK signaling pathway, regulating different organ systems, including the CNS. Increased activation and dysregulation of the MEK pathway is reportedly observed in 30% of all malignancies. The diversity of MEK renders it a prime target for inhibition in treating cancer. MEK inhibition has been studied in the context of melanoma, non-small cell lung cancer, breast cancer, and colorectal cancer, among others. The standard treatment for glioblastoma (resection, temozolomide, and radiation) remains relatively futile, which warrants alternative treatment options. Therefore, MEK inhibition has garnered more attention in recent years as investigators have explored its role in treating the most aggressive and most common primary brain tumor, glioblastoma. MEK inhibitors have shown efficacy in pre-clinical investigations as well as some promise in clinical trials which have demonstrated improved overall and progression-free survival. This underscores the potential of MEK inhibition in glioblastoma therapy and represents an area that likely warrants further research. However, there are few comprehensive and unifying reviews discussing the current state of MEK inhibition in glioblastoma therapy. We begin this review by detailing the normal function of MEK as it pertains to the CNS. We then compiled relevant pre-clinical and clinical studies to investigate recent research discussing the role of MEK inhibition in glioblastoma therapy. Full article

Neurofibromatosis type 1 (NF1) is a genetic disorder characterized by a wide range of clinical manifestations, including café-au-lait macules, cutaneous neurofibromas, and an increased risk of certain malignancies. Historically, there has been no approved medical therapy specifically aimed at achieving tumor shrinkage or regression. Surgical intervention is often limited by factors such as the inaccessibility of the tumor location, involvement of critical tissues, suboptimal timing, or the inability to achieve complete resection. Recent advancements in targeted therapies, particularly MEK inhibitors, have introduced promising treatment options for patients with severe manifestations of NF1. This review highlights the pathophysiology of NF1 and the therapeutic role of MEK inhibitors and presents a detailed case study of a patient treated with selumetinib, a novel MEK inhibitor. While the therapeutic potential of selumetinib has been demonstrated in preclinical and clinical studies, including those involving Japanese patients, this review aims to evaluate its application in real-world clinical practice. A comprehensive discussion of the case study provides insights into the efficacy, safety, and clinical challenges associated with selumetinib treatment, offering valuable perspectives for its use in managing NF1. Full article

Background/objective: Mucosal melanoma (MM) is a poorly responsive, rare and aggressive subtype with few cases having targetable recurrent driver mutations, although Ras/MAPK and PI3K/AKT/mTOR signaling pathway activations are common. Eventual tumor evasion of targeted therapy continues to limit treatment success. Adequate models are necessary to address therapeutic resistance. The relatively greater incidence of naturally occurring MM in dogs, as well as its comparable clinical and pathological characteristics to human MM, represents an opportunity for study as a human MM patient surrogate. Resistance-promoting crosstalk between Ras/MAPK and PI3K/AKT/mTOR signaling under trametinib inhibition of MEK was studied in canine MM. Emphasis was placed on the suppressive effect of trametinib on cell cycle entry and its potential role in drug resistance. Methods: D-type cyclins were investigated following trametinib treatment of five MM cell lines exhibiting differential drug sensitivities. Signaling pathway activation, proliferation, survival, cell death, and cell cycle were analyzed in the context of D-type cyclin expression. Cyclin D2 expression was manipulated using siRNA knockdown or inducible recombinant overexpression. Results: Trametinib diminished cyclin D1 in all cell lines. While relatively trametinib-resistant MM cells exhibited capacity to upregulate cyclin D2, which promoted proliferation, sensitive MM cells lacked similar cyclin D2 compensation. Inhibition of the compensatory cyclin D2 in resistant cells conferred sensitivity. Induced cyclin D2 overexpression in otherwise trametinib-sensitive MM cells promoted survival. Upregulated PI3K/AKT/mTOR signaling under trametinib treatment was suppressed by mTORC1/2 inhibition, which similarly diminished cyclin D2 response. Conclusions: The compensatory switch from preferential reliance on cyclin D1 to D2 plays a role in MM resistance to MEK inhibition. Full article

Background/Objectives: RAF pathway aberrations are one of the hallmarks of lung cancer. Sorafenib is a multi-kinase inhibitor targeting the RAF pathway and is FDA-approved for several cancers, yet its efficacy in lung cancer is controversial. Previous clinical research showed that a ARAF p.S214C mutation exhibited exceptional responsiveness to sorafenib in lung adenocarcinoma. Methods: Considering this promising clinical potential, the oncogenic potential and sorafenib response of the ARAF p.S214C mutation were investigated using lung cancer models. ARAF p.S214C mutant, ARAF wild-type (WT), and EGFP control genes were ectopically expressed in lung adenocarcinoma cell lines retroviral transduction. In vitro and in vivo sorafenib sensitivity studies were performed, followed by transcriptomics and proteomics analyses. Results: Compared to the ARAF-WT and EGFP-engineered cells, the ARAF p.S214C-engineered cells activated Raf-MEK-ERK signaling and exhibited enhanced oncogenic potential in terms of in vitro cell proliferation, colony and spheroid formation, migration, and invasion abilities, as well as in vivo tumorigenicity. The ARAF p.S214C-engineered cells also displayed heightened sensitivity to sorafenib in vitro and in vivo. RNA sequencing and reverse-phase protein array analyses demonstrated elevated expression of genes and proteins associated with tumor aggressiveness in the ARAF p.S214C mutants, and its sorafenib sensitivity was likely moderated through inhibition of the cell cycle and DNA replication. The ERK and PI3K signaling pathways were also significantly deregulated in the ARAF p.S214C mutants regardless of sorafenib treatment. Conclusions: This study demonstrates the oncogenicity and sorafenib sensitivity of the ARAF p.S214C mutation in lung cancer cells, which may serve as a biomarker for predicting the sorafenib response in lung cancer patients. Importantly, investigating the gene–drug sensitivity pairs in clinically exceptional responders may guide and accelerate personalized cancer therapies based on specific tumor mutations. Full article

Janus kinase 2 (JAK2) inhibitors have gained regulatory approval for treating various human diseases. While the JAK2/signal tranducer and activator of transcription 3 (STAT3) pathway plays a role in tumorigenesis, JAK2/STAT3 inhibitors have shown limited therapeutic efficacy in triple-negative breast cancer (TNBC). In this study, we assessed the antiproliferative effects of clinically approved JAK2 inhibitors in TNBC cell lines (MDA-MB-231 and HS578T) using the MTT assay. Among the four JAK2 inhibitors evaluated (fedratinib, cerdulatinib, peficitinib, and filgotinib), fedratinib significantly inhibited the proliferation of TNBC cells with IC₅₀ values below 2 μM. Fedratinib also demonstrated superior efficacy in inhibiting long-term colony formation compared to other JAK2 inhibitors. Western blot analyses showed that fedratinib uniquely inhibits the phosphoinositide 3-kinase (PI3K)/AKT pathway and moderately affects the MAP kinase/ERK kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway, in addition to targeting JAK2/STAT3 signaling. Moreover, fedratinib distinctly decreased MYC and cyclin D1 protein levels while inducing poly (ADP-ribose) polymerase (PARP) cleavage and apoptotic cell death more effectively than other JAK2 inhibitors. We next investigated the effects of simultaneously inhibiting JAK2/STAT3 together with the MEK/ERK or PI3K/AKT pathways, as well as the impact of triple pathway inhibition. Notably, combining ceduratinib with either cobimetinib (MEK inhibitor) and ipatasertib (AKT inhibitor) or trametinib (MEK inhibitor) and alpelisib (PI3K inhibitor) mimicked the effects of fedratinib on the cell proliferation, MYC and cyclin D1 suppression, and pro-apoptotic protein induction. These finding suggest that JAK2 inhibition enhances the anticancer effects of concurrent MEK/ERK and PI3K/AKT pathway inhibition, while JAK2 inhibition alone shows minimal efficacy in TNBC cells. Full article

Recent diagnostic advances reveal that lymphatic disease in Noonan syndrome (NS) and other NS-like RASopathies often stems from central conducting lymphatic anomalies (CCLAs). The RAS/MAPK-ERK pathway plays a central role in lymphangiogenesis. Targeting this pathway with MEK-inhibitor trametinib has emerged as a promising therapeutic strategy for managing CCLAs in patients with NS-like RASopathies. This case series assessed the clinical outcomes of trametinib therapy in eight patients with NS-like RASopathies and CCLA, each offering unique insights into the therapeutic efficacy of MEK inhibition. In infants, a lower dose of 0.01 mg/kg/day and earlier discontinuation of trametinib therapy effectively alleviated the symptoms of congenital chylothorax and rescued the lymphatic phenotype, compared to similar published cases. Moreover, four patients aged >11 y showed a slower response and did not achieve complete symptomatic recovery. In conclusion, it is advised to consider trametinib therapy for patients with severe, therapy-refractory CCLA in patients with NS-like RASopathies. However, individual responses to trametinib therapy may vary, with some patients demonstrating more favorable outcomes than others. Further investigation into potential enhancers and suppressors of the lymphatic phenotype is necessary for more accurate treatment predictions. While these factors are likely genetic, we cannot rule out other intrinsic or physiological factors. Full article

Skin cancer, particularly melanoma, remains a major public health concern due to its high mortality rate. Current treatment options, including chemotherapy with dacarbazine and doxorubicin, have shown limited efficacy, achieving only a 20% objective response rate over six months, along with severe side effects such as cardiotoxicity. Given these limitations, there is a growing interest in herbal medicine as a source of novel anticancer compounds. Bambusa stenostachya, a bamboo species native to Taiwan, was investigated for its potential anti-melanoma properties using network pharmacology and molecular docking. LC-MS analysis identified seven bioactive compounds, including quinic acid and isovitexin, which satisfied Lipinski’s drug-likeness criteria. Among the seven bioactive compounds identified, five belong to the flavonoid family, while two are classified as phenolic compounds that modulate signaling pathways related to cancer and exhibit antioxidant activity, respectively. Through pathway enrichment analysis, four key melanoma-associated genes (PIM1, MEK1, CDK2, and PDK1) were identified as potential therapeutic targets. Ensemble docking results demonstrated that naringin-7-rhamnoglucoside exhibited the highest binding affinity (−6.30 kcal/mol) with phosphoinositide-dependent kinase-1, surpassing the affinities of standard chemotherapeutic agents. Additionally, the average docking scores for naringin-7-rhamnoglucoside and the remaining three proteins were as follows: PIM1 (−5.92), MEK1 (−6.07), and CDK2 (−5.26). These findings suggest that the bioactive compounds in B. stenostachya may play a crucial role in inhibiting melanoma progression by modulating metabolic and signaling pathways. Further in vitro and in vivo studies are necessary to validate these computational findings and explore the potential of B. stenostachya as a complementary therapeutic agent for melanoma. Full article

Aberrant activation of the mitogen-activated protein kinase (MAPK) cascade promotes oncogenic transcriptomes. Despite efforts to inhibit oncogenic kinases, such as BRAFV600E, tumor responses in patients can be heterogeneous and limited by drug resistance mechanisms. Here, we describe patient tumors that acquired COP1 or DET1 mutations after treatment with the BRAF^V600E inhibitor vemurafenib. COP1 and DET1 constitute the substrate adaptor of the E3 ubiquitin ligase CRL4^COP1/DET1, which targets transcription factors, including ETV1, ETV4, and ETV5, for proteasomal degradation. MAPK-MEK-ERK signaling prevents CRL4^COP1/DET1 from ubiquitinating ETV1, ETV4, and ETV5, but the mechanistic details are still being elucidated. We found that patient mutations in COP1 or DET1 inactivated CRL4^COP1/DET1 in melanoma cells, stabilized ETV1, ETV4, and ETV5, and conferred resistance to inhibitors of the MAPK pathway. ETV5, in particular, enhanced cell survival and was found to promote the expression of the pro-survival gene BCL2A1. Indeed, the deletion of pro-survival BCL2A1 re-sensitized COP1 mutant cells to vemurafenib treatment. These observations indicate that the post-translational regulation of ETV5 by CRL4^COP1/DET1 modulates transcriptional outputs in ERK-dependent cancers, and its inactivation contributes to therapeutic resistance. Full article

Melanomas quickly acquire resistance to vemurafenib, an important therapeutic for BRAFV600 mutant melanomas. Although combating vemurafenib resistance (VemR) to counter mitochondrial metabolic shift using mitochondria-targeting therapies has promise, no studies have analyzed the relationship between vemurafenib tolerance levels and metabolic plasticity. To determine how vemurafenib endurance levels drive metabolic plasticity, we developed isogenic BRAFV600E VemR melanoma models with variant vemurafenib tolerances and performed an integrative analysis of metabolomic and transcriptome alterations using metabolome, Mitoplate-S1, Seahorse, and RNA-seq assays. Regardless of drug tolerance differences, both VemR models display resistance to MEK inhibitor and sensitivity to Wnt/β-catenin inhibitor, ICG-001. β-catenin, MITF, and ABCB5 levels are upregulated in both VemR models, and ICG-001 treatment restored vemurafenib sensitivity with reductions in MITF, ABCB5, phospho-ERK1/2, and mitochondrial respiration. Whereas β-catenin signaling induced TCA cycle and OXPHOS in highly drug tolerant A2058VemR cells, it activated pentose phosphate pathway in M14VemR cells with low vemurafenib tolerance, both of which are inhibited by ICG-001. These data implicate an important role for Wnt/β-catenin signaling in VemR-induced metabolic plasticity. Our data demonstrate that drug tolerance thresholds play a direct role in driving metabolic shifts towards specific routes, thus providing a new basis for delineating VemR melanomas for metabolism-targeting therapies. Full article

NRAS-mutant melanoma represents a clinically challenging subset of melanoma with limited effective therapies and intrinsic resistance to targeted MEK inhibition. Recent findings highlight protein S-nitrosylation, a redox-dependent post-translational modification as a critical modulator of MEK-ERK signaling and immune evasion in this context. In this commentary, we discuss how S-nitrosylation of MAPK components, including MEK and ERK, sustains oncogenic signaling and attenuates immunogenic cell death. Targeting this modification with nitric oxide synthase (NOS) inhibitors such as L-NAME, L-NMMA and 1400w restore sensitivity of MEK inhibitor, promotes dendritic cell activation, and enhances CD8+ T cell infiltration in preclinical models such as immunogenic mouse models and individual patient derived, primary melanoma cells. We also explore the emerging role of S-nitrosylation in regulating macrophage-mediated immune surveillance and propose translational strategies for combining redox modulation with targeted and immune therapies. These insights offer a compelling framework for overcoming therapeutic resistance and reprogramming the tumor immune microenvironment to activate the cytotoxic T-cells and enhance the responses to immunotherapy in NRAS-driven cancers. Full article

Targeting the cell cycle has become a focus of cancer research bearing impressive results with the introduction of CDK4/6 inhibitors in the treatment of ER-positive/HER2-negative breast cancers. However, no definitive benefit in other cancers has been observed. In gastrointestinal cancers, despite preclinical studies pinpointing positive effects on cancer inhibition in pre-clinical models, no positive clinical trials have been published with CDK4/6 inhibitors. Several biomarkers have been proposed in breast cancers, where the field is more advanced, and include up-regulations of the inhibited kinases CDK4 and CDK6 and their partner cyclin D as well as the main target of phosphorylation, RB. Up-regulation of Cyclin E, an E2F1/RB regulated gene, also arises as a marker of CDK4/6 inhibition resistance. Signaling from receptor tyrosine kinase pathways through KRAS/BRAF/MEK and PI3K/AKT/mTOR are also implicated in feedback CDK4/6 activation and inhibitors resistance. In gastrointestinal cancers, some of these biomarkers have also proven valuable in predicting sensitivity to CDK4/6 inhibitors and would lead markers to guide clinical development. Modulation of the tumor microenvironment, where immune cells are prominent components, arises as a feature of CDK4/6 inhibition and could be harnessed in therapeutic combinations. Full article

The incidence of melanoma is increasing globally, even in the wake of increased risk factor awareness and a growing body of advanced therapeutic options. It is apparent that the treatment of melanoma will remain a topic of worry in areas of the world under high ultraviolet exposure and areas that harbor individuals with fair skin phenotypes. In the wake of such concern, the potential of immunotherapy and various targeted therapeutics to treat late-stage melanoma is increasing. In addition to the growing arsenal of PD-1 and PD-L1 immune checkpoint inhibitors, other targeted therapies are being developed and tested to treat melanoma. BRAF/MEK inhibitors target a key proliferative pathway in melanoma, offering clinical benefit but limited durability. Next-generation agents and triplet therapy with immunotherapy aim to improve outcomes. Androgen receptor signaling may also modulate responses to both targeted and immune-based treatments. Bispecific T cell engagers assist with guiding the body’s own T cells to tumors where they release toxins that kill the tumor cell. Personalized neoantigen vaccines target tumor-specific antigens by sequencing a patient’s cancerous cells to create tailored vaccines that elicit a strong and specific immune response. Tumor-infiltrating lymphocytes are autologous lymphocytes reinfused back into the host that are showing efficacy in the treatment of advanced melanoma. Together, these therapies are advancing the arsenal of chemotherapeutic options that can be used to inhibit the progression of melanoma. Full article