Search Results (86)

Colorectal cancer (CRC) remains a leading cause of cancer-related mortality globally, posing significant treatment challenges, particularly in its metastatic form (mCRC). This review comprehensively examines the pivotal role of RAS mutations, specifically KRAS and NRAS, which are detected in approximately 40–45% of mCRC cases, and their impact on treatment decisions and patient outcomes. We assess the effectiveness of standard treatments within the RAS mutant population, highlighting the challenges and limitations these therapies face. Recent advancements in targeted therapies, particularly the focus on novel agents such as KRAS G12C inhibitors, including sotorasib and adagrasib, have shown promising efficacy in overcoming resistance to conventional treatments. Furthermore, this review discusses future directions, emphasizing the need for research into non-RAS targets to address the complexities of resistance mechanisms and improve therapeutic outcomes. This review aims to provide a detailed overview of the current treatments and innovative approaches, supporting the development of personalized management strategies for patients with mCRC. Full article

Background: Canine oral melanoma (COM) is an aggressive and often fatal neoplasm in dogs, with clinical and molecular similarities to human melanoma. Despite its relevance as a comparative oncology model, the molecular mechanisms underlying COM remain poorly understood. This study aimed to characterize gene expression profiles in COM to identify differentially expressed genes (DEGs), potential biomarkers, and therapeutic targets. Methods: In this pilot study, we performed RNA sequencing (RNA-seq) on tumor and healthy oral tissue samples from dogs. Two independent analytical pipelines—Bowtie2-DESeq2 and HISAT-StringTie-Ballgown—were used to ensure robustness in DEG detection. We also conducted pathway enrichment and isoform-level analyses to investigate biological processes and alternative splicing events. Results: Both approaches identified a core set of 929 common DEGs. Key oncogenic pathways, including MAPK/ERK and cell cycle regulation, were significantly affected, with notable upregulation of BRAF, NRAS, CDK4, and MITF (log2FC = 2.86, p < 0.001). The transcription factor SOX10 and the cytokine IL-33, both previously implicated in melanoma progression, were consistently overexpressed. Additionally, NF1, a known RAS pathway inhibitor, was also upregulated. Isoform analysis revealed novel transcript variants, suggesting a complex layer of post-transcriptional regulation in COM. Many DEGs remained uncharacterized, and chromosomal distribution analysis highlighted potential genomic influences. Conclusions: Our findings provide new insights into the molecular landscape of COM, reinforcing its utility as a model for human melanoma. The identification of conserved oncogenic pathways and novel transcript variants opens avenues for further functional studies and the development of targeted therapies in both veterinary and human oncology. 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

Acute myeloid leukemia (AML) has traditionally been linked to a poor prognosis, particularly in older patients who are ineligible for intensive chemotherapy. The advent of Venetoclax, a powerful oral BH3 mimetic targeting anti-apoptotic protein BCL2, has significantly advanced AML treatment. Its combination with the hypomethylating agent azacitidine (AZA/VEN) has become a standard treatment for this group of AML patients, demonstrating a 65% overall response rate and a median overall survival of 14.7 months, compared to 22% and 8 months with azacitidine monotherapy, respectively. However, resistance and relapses remain common, representing a significant clinical challenge. Recent studies have identified molecular alterations, such as mutations in FLT3-ITD, NRAS/KRAS, TP53, and BAX, as major drivers of resistance. Additionally, other factors, including metabolic changes, anti-apoptotic protein expression, and monocytic or erythroid/megakaryocytic differentiation status, contribute to treatment failure. Clinical trials are exploring strategies to overcome venetoclax resistance, including doublet or triplet therapies targeting IDH and FLT3 mutations; novel epigenetic approaches; menin, XPO1, and MDM2 inhibitors; along with immunotherapies like monoclonal antibodies and antibody–drug conjugates. A deeper understanding of the molecular mechanisms of resistance through single-cell analysis will be crucial for developing future therapeutic strategies. Full article

Background/Objectives: Acute myeloid leukemia (AML) is a rare hematological malignancy with a poor prognosis. Activating c-Kit (CD117) mutations occur in 5% of de novo AML and 30% of core-binding factor (CBF) AML, leading to worse clinical outcomes. Posttranslational modifications, particularly with myristic and palmitic acid, are crucial for various cellular processes, including membrane organization, signal transduction, and apoptosis regulation. However, most research has focused on solid tumors, with limited understanding of these mechanisms in AML. Fatty acid synthase (FASN), a key palmitoyl-acyltransferase, regulates the subcellular localization, trafficking, and degradation of target proteins, such as H-Ras, N-Ras, and FLT3-ITDmut receptors in AML. Methods: In this study, we investigated the role of FASN in two c-Kit-N822K-mutated AML cell lines using FASN knockdown via shRNA and the FASN inhibitor TVB-3166. Functional implications, including cell proliferation, were assessed through Western blotting, mass spectrometry, and PamGene. Results: FASN inhibition led to an increased phosphorylation of c-Kit (p-c-Kit), Lyn kinase (pLyn), MAP kinase (pMAPK), and S6 kinase (pS6). Furthermore, we observed sustained high expression of Gli1 in Kasumi1 cells following FASN inhibition, which is well known to be mediated by the upregulation of pS6. Conclusions: The combination of TVB-3166 and the Gli inhibitor GANT61 resulted in a significant reduction in the survival of Kasumi1 cells. Full article

Malignant melanoma is a lethal skin cancer containing melanoma-initiating cells (MICs), implicated in tumorigenesis, invasion, and drug resistance, and characterized by an elevated expression of stem cell markers, including CD133. siRNA knockdown of CD133 has been previously shown to enhance apoptosis induced by the MEK inhibitor trametinib in melanoma cells. This study investigates the underlying mechanisms of CD133’s anti-apoptotic activity in patient-derived BAKP melanoma, harboring the difficult-to-treat NRAS^Q61K driver mutation, after CRISPR-Cas9 CD133 knockout or Doxycycline (Dox)-inducible re-expression of CD133. CD133 knockout in BAKP cells increased trametinib-induced apoptosis by reducing anti-apoptotic p-AKT and p-BAD and increasing pro-apoptotic BAX. Conversely, Dox-induced CD133 expression diminished apoptosis in trametinib-treated cells, coincident with elevated p-AKT, p-BAD, and decreased activation of BAX and caspase-3. However, trametinib in combination with pan-AKT inhibitor capivasertib reduced cell survival as measured by XTT viability assays and apoptosis and colony formation assays, independent of CD133 status. CD133 may therefore activate a survival pathway wherein (1) increased AKT phosphorylation and activation induces (2) BAD phosphorylation and inactivation, which (3) decreases BAX activation, and (4) reduces caspases-3 activity and caspase-mediated PARP cleavage, leading to apoptosis suppression and drug resistance in melanoma. In vivo mouse xenograft studies using Dox-inducible melanoma cells revealed increased rates of tumor growth after induction of CD133 expression in trametinib-treated +Dox mice, an effect which was synergistically suppressed by combination treatment. Targeting nodes of the AKT and MAPK survival pathways with trametinib and capivasertib highlights the potential for combination therapies for NRAS-mutant melanoma stem cells for the development of more effective treatments for patients with high-risk melanoma. Full article

The expression level of Programmed Death-Ligand 1 (PD-L1) determined by the immunohistochemical method is currently approved to test the potential efficacy of immune-checkpoint inhibitors and to candidate patients with Non-Small Cell Lung Cancer (NSCLC) for treatment with immunotherapeutic drugs. As part of the CORELAB (New prediCtivebiOmaRkers of activity and Efficacy of immune checkpoint inhibitors in advanced non-small cell Lung cArcinoma) project, aimed at identifying new predictive and prognostic biomarkers in NSCLC patients receiving immunotherapeutic drugs, we investigated the role of circulating tumor DNA (ctDNA) molecular characterization as an additional predictive biomarker. We analyzed plasma ctDNA by targeted Next Generation Sequencing in a subset of 50 patients at different time points. ctDNA content was inversely correlated with the clinical outcome both at a baseline and after 2 months of treatment. OS was significantly higher in patients with ≥50% ctDNA reduction. TP53 and KRAS were the most frequently mutated genes, and patients with KRAS and/or TP53 mutations showed worse outcomes than patients without detectable variants or with mutations in other genes. Fewer common variants were found in BRAF, EGFR, MAP2K1, MET, NRAS, and PIK3CA genes. Our data demonstrated that molecular characterization of ctDNA and also its quantitative evaluation could serve as a dynamic, real-time prognostic, and predictive biomarker, enabling regular molecular monitoring of therapy efficacy in support of other medical examinations. Full article

Background: There are no active treatment options for patients with progressive melanoma brain metastases (MBM) failing immune checkpoint blockade (ICB) and BRAF/MEK inhibitors (BRAF/MEKi). Regorafenib (REGO), an oral multi-kinase inhibitor (incl. RAF-dimer inhibition), can overcome adaptive resistance to BRAF/MEKi in preclinical models. Methods: This is a single-center retrospective case series of patients with refractory MBM treated with REGO plus BRAF/MEKi (compassionate use). Results: A total of 22 patients were identified (18 BRAF-mutant, 4 NRAS^Q61-mutant; 19 with progressive MBM; 11 on corticosteroids). Thirteen BRAF^V600-mutant patients were progressing on BRAF/MEKi at the time of REGO association. BRAF-mutant patients received REGO (40–80 mg once daily) combined with BRAF/MEKi, NRAS-mutant patients were treated with REGO + MEKi (+low-dose BRAFi to mitigate skin-toxicity). Grade 3 TRAE included arterial hypertension (n = 4) and maculopapular rash (n = 3). There were no G4/5 TRAE. In BRAF-mutant patients, overall and intracranial objective response rates (overall ORR and IC-ORR) were 11 and 29%, and overall and intracranial disease control rates (overall DCR and IC-DCR) were 44 and 59%, respectively. In NRAS-mutant patients overall ORR and IC-ORR were 0 and 25% and overall DCR and IC-DCR were 25 and 50%, respectively. The median PFS and OS were, respectively, 7.1 and 16.4 weeks in BRAF-mutant and 8.6 and 10.1 weeks in NRAS-mutant patients. Conclusions: In heavily pretreated patients with refractory MBM, REGO combined with BRAF/MEKi demonstrated promising anti-tumor activity with an acceptable safety profile. In BRAF^V600-mutant melanoma patients, responses cannot solely be attributed to BRAF/MEKi rechallenge. Further investigation in a prospective trial is ongoing to increase understanding of the efficacy. Full article

Colorectal cancer (CRC) arises through a combination of genetic and epigenetic alterations that affect key pathways involved in tumor growth and progression. This review examines the major molecular pathways driving CRC, including Chromosomal Instability (CIN), Microsatellite Instability (MSI), and the CpG Island Methylator Phenotype (CIMP). Key mutations in genes such as APC, KRAS, NRAS, BRAF, and TP53 activate signaling pathways like Wnt, EGFR, and PI3K/AKT, contributing to tumorigenesis and influencing responses to targeted therapies. Resistance mechanisms, including mutations that bypass drug action, remain challenging in CRC treatment. This review highlights the role of molecular profiling in guiding the use of targeted therapies such as tyrosine kinase inhibitors and immune checkpoint inhibitors. Novel combination treatments are also discussed as strategies to improve outcomes and overcome resistance. Understanding these molecular mechanisms is critical to advancing personalized treatment approaches in CRC and improving patient prognosis. Full article

Amelanotic melanoma (AM) is a subtype of hypomelanotic or completely amelanotic melanoma. AM is a rare subtype of melanoma that exhibits a higher recurrence rate and aggressiveness as well as worse surveillance than typical melanoma. AM shows a dysregulation of melanin production, cell cycle control, and apoptosis pathways. Knowing these pathways has an application in medicine due to targeted therapies based on the inhibiting elements of the abovementioned pathways. Therefore, we summarized and discussed AM biochemical and molecular induction pathways and personalized medicine approaches, clinical management, and future directions due to the fact that AM is relatively rare. AM is commonly misdiagnosed. Hence, the role of biomarkers is becoming significant. Nonetheless, there is a shortage of biomarkers specific to AM. BRAF, NRAS, and c-KIT genes are the main targets of therapy. However, the role of BRAF and KIT in AM varied among studies. BRAF inhibitors combined with MAK inhibitors demonstrate better results. Immune checkpoint inhibitors targeting CTLA-4 combined with a programmed death receptor 1 (PD-1) show better outcomes than separately. Fecal microbiota transplantation may overcome resistance to immune checkpoint therapy of AM. Immune-modulatory vaccines against indoleamine 2,3-dioxygenase (IDO) and PD ligand (PD-L1) combined with nivolumab may be efficient in melanoma treatment. Full article

Background: When monotherapy with PD-1 inhibitors in metastatic melanoma fails, there are currently no standard second-line choices. In case of the unavailability of clinical trials, ipilimumab represents a possible alternative treatment. Methods: We collected data of 44 patients who received ipilimumab after the failure of PD-1 inhibitors from July 2017 to May 2023 at our Institute. Overall survival (OS), progression-free survival (PFS), and post-progression survival (PPS) based on BRAF or NRAS mutation status, sex, and the presence of brain metastases were estimated using the Kaplan–Meier method. Cox regression was used to evaluate independence in multivariate analysis. The objective response rate (ORR) was estimated based on RECIST 1.1. Results: Among the 44 patients enrolled in this study, 28 BRAF-wildtype, 9 BRAF-mutated, and 7 NRAS-mutated patients were identified. OS analysis showed a significant difference between wildtype and BRAF- or NRAS-mutated patients: 23.2 months vs 5.3 and 4.59, respectively, p = 0.017. The presence of brain metastases and BRAF or NRAS mutation were independent factors for mortality in multivariate analysis. Conclusions: In case of failure to enroll patients in innovative clinical trials, second-line ipilimumab still represents an effective therapy in patients with metastatic wildtype melanoma and in the absence of brain metastases. Full article

Acute myeloid leukemia (AML) is an aggressive hematologic neoplasia with a complex polyclonal architecture. Among driver lesions, those involving the FLT3 gene represent the most frequent mutations identified at diagnosis. The development of tyrosine kinase inhibitors (TKIs) has improved the clinical outcomes of FLT3-mutated patients (Pt). However, overcoming resistance to these drugs remains a challenge. To unravel the molecular mechanisms underlying therapy resistance and clonal selection, we conducted a longitudinal analysis using a single-cell DNA sequencing approach (MissionBioTapestri® platform, San Francisco, CA, USA) in two patients with FLT3-mutated AML. To this end, samples were collected at the time of diagnosis, during TKI therapy, and at relapse or complete remission. For Pt #1, disease resistance was associated with clonal expansion of minor clones, and 2nd line TKI therapy with gilteritinib provided a proliferative advantage to the clones carrying NRAS and KIT mutations, thereby responsible for relapse. In Pt #2, clonal architecture was less complex, and 1st line TKI therapy with midostaurin was able to eradicate the leukemic clones. Our results corroborate previous findings about clonal selection driven by TKIs, highlighting the importance of a deeper characterization of individual clonal architectures for choosing the best treatment plan for personalized approaches aimed at optimizing outcomes. Full article

Purpose: This study explores the potential of pre-clinical in vitro cell line response data and computational modeling in identifying the optimal dosage requirements of pan-RAF (Belvarafenib) and MEK (Cobimetinib) inhibitors in melanoma treatment. Our research is motivated by the critical role of drug combinations in enhancing anti-cancer responses and the need to close the knowledge gap around selecting effective dosing strategies to maximize their potential. Results: In a drug combination screen of 43 melanoma cell lines, we identified specific dosage landscapes of panRAF and MEK inhibitors for NRAS vs. BRAF mutant melanomas. Both experienced benefits, but with a notably more synergistic and narrow dosage range for NRAS mutant melanoma (mean Bliss score of 0.27 in NRAS vs. 0.1 in BRAF mutants). Computational modeling and follow-up molecular experiments attributed the difference to a mechanism of adaptive resistance by negative feedback. We validated the in vivo translatability of in vitro dose–response maps by predicting tumor growth in xenografts with high accuracy in capturing cytostatic and cytotoxic responses. We analyzed the pharmacokinetic and tumor growth data from Phase 1 clinical trials of Belvarafenib with Cobimetinib to show that the synergy requirement imposes stricter precision dose constraints in NRAS mutant melanoma patients. Conclusion: Leveraging pre-clinical data and computational modeling, our approach proposes dosage strategies that can optimize synergy in drug combinations, while also bringing forth the real-world challenges of staying within a precise dose range. Overall, this work presents a framework to aid dose selection in drug combinations. Full article

Advances in melanoma research have unveiled critical insights into its genetic and molecular landscape, leading to significant therapeutic innovations. This review explores the intricate interplay between genetic alterations, such as mutations in BRAF, NRAS, and KIT, and melanoma pathogenesis. The MAPK and PI3K/Akt/mTOR signaling pathways are highlighted for their roles in tumor growth and resistance mechanisms. Additionally, this review delves into the impact of epigenetic modifications, including DNA methylation and histone changes, on melanoma progression. The tumor microenvironment, characterized by immune cells, stromal cells, and soluble factors, plays a pivotal role in modulating tumor behavior and treatment responses. Emerging technologies like single-cell sequencing, CRISPR-Cas9, and AI-driven diagnostics are transforming melanoma research, offering precise and personalized approaches to treatment. Immunotherapy, particularly immune checkpoint inhibitors and personalized mRNA vaccines, has revolutionized melanoma therapy by enhancing the body’s immune response. Despite these advances, resistance mechanisms remain a challenge, underscoring the need for combined therapies and ongoing research to achieve durable therapeutic responses. This comprehensive overview aims to highlight the current state of melanoma research and the transformative impacts of these advancements on clinical practice. Full article

The combination of chemotherapy and targeted therapy has been validated in non-small-cell lung cancer (NSCLC) patients with EGFR mutations. We therefore investigated whether this type of combined approach could be more widely used by targeting other genetic alterations present in NSCLC. PDXs were generated from patients with NSCLC adenocarcinomas (ADCs) and squamous-cell carcinomas (SCCs). Targeted NGS analyses identified various molecular abnormalities in the MAPK and PI3K pathways and in the cell cycle process in our PDX panel. The antitumor efficacy of targeted therapies alone or in combination with chemotherapy was then tested in vivo. We observed that trametinib, BKM120, AZD2014 and palbociclib increased the efficacy of each chemotherapy in SCC PDXs, in contrast to a non-insignificant or slight improvement in ADCs. Furthermore, we observed high efficacy of trametinib in KRAS-, HRAS- and NRAS-mutated tumors (ADCs and SCCs), suggesting that the MEK inhibitor may be useful in a wider population of NSCLC patients, not just those with KRAS-mutated ADCs. Our results suggest that the detection of pathogenic variants by NGS should be performed in all NSCLCs, and particularly in SCCs, to offer patients a more effective combination of chemotherapy and targeted therapy. Full article