Targeting Alterations in the RAF-MEK Pathway

Overcoming multiple barriers to deliver photo-gene system for glioma-targeted combined therapy

Overcoming multiple barriers to deliver macromolecular drugs is an urgent challenge for glioma treatment. Herein, a strategy of protein corona-regulation synergizing with photoactivation based on T10 peptide-modified and indocyanine green (ICG)-loaded dendrigraft poly-L-lysines was proposed to augment prime editing therapy of glioma. First, the modified T10 peptide could escape the interference barrier of protein crown in blood via its specific binding with endogenous transferrin, thus crossing the blood-brain barrier (BBB) and achieving the targeting recognition of glioma cells. Next, the loaded ICG could weaken the tumor stromal barrier, decrease the cell membrane barrier and escape the lysosomal degradation/autophagy barrier via its photothermal and photodynamic effects. Subsequently, a therapeutic gene that could downregulate p-ERK1/2 for tumor growth inhibition and immunoregulation could be effectively delivered into the glioma cells. The glioma-targeted photo-gene combined immunotherapy effectively inhibit the glioma growth, especially co-dosing with the PD-1 antibody.

New insights into the function and therapeutic potential of RNA-binding protein TRBP in viral infection, chronic metabolic diseases, brain disorders and cancer

RNA-binding proteins (RBPs) and non-coding RNAs are crucial trans-acting factors that bind to specific cis-acting elements in mRNAs, thereby regulating their stability and translation. The trans-activation response (TAR) RNA-binding protein (TRBP) recognizes precursor microRNAs (pre-miRNAs), modulates miRNA maturation, and influences miRNA interference (mi-RNAi) mediated by the RNA-induced silencing complex (RISC). TRBP also directly binds and mediates the degradation of certain mRNAs. Thus, TRBP acts as a hub for regulating gene expression and influences a variety of biological processes, including immune evasion, metabolic abnormalities, stress response, angiogenesis, hypoxia, and metastasis. Aberrant TRBP expression has been proven to be closely related to the initiation and progression of diseases, such as viral infection, chronic metabolic diseases, brain disorders, and cancer. This review summarizes the roles of TRBP in cancer and other diseases, the therapeutic potential of TRBP inhibition, and the current status of drug discovery on TRBP.

Type II RAF inhibitor tovorafenib for the treatment of pediatric low-grade glioma

INTRODUCTION

Pediatric low-grade glioma (pLGG) is the most prevalent childhood brain tumor group, currently regarded as a chronic disease. On 23 April 2024, the U.S. FDA approved a new type II RAF inhibitor, tovorafenib (OJEMDATM), previously known as DAY101, for the treatment of patients aged 6 months and older with relapsed or refractory (R/R) pLGG harboring a BRAF fusion or rearrangement, or BRAF V600E mutation.

AREAS COVERED

This article aims to review the pharmacological properties of tovorafenib and evaluate its efficacy and safety in the treatment of R/R pLGG. We conducted a systematic search of PubMed and Web of Science databases for English-language publications related to tovorafenib, including journal articles and conference abstracts, up through 20 August 2024.

EXPERT OPINION

As the first and only FDA-approved medicine for children with BRAF fusions or rearrangements, which are the most common molecular alteration in pLGG, tovorafenib shows superior central nervous system penetration without the paradoxical activation of the MAPK pathway reported for type I BRAF inhibitors. Phase 1 and the pivotal phase 2 trials have demonstrated that tovorafenib monotherapy is generally well-tolerated and exhibits encouraging signs of meaningful, rapid and sustained clinical activity in children and young adults with BRAF-altered pLGG.

The Prevalence and Prognostic Implications of BRAF K601E Mutations in Thyroid Neoplasms: A Systematic Review and Meta-Analysis

BACKGROUND

Activating mutations in the BRAF oncogene occur in 45% of papillary thyroid carcinomas (PTCs). Though less studied, K601E may identify a clinically distinct subset of thyroid neoplasms.

METHODS

A bioinformatics assessment was conducted using the COSMIC database and in silico data analysis. A systematic search was conducted through August 2024 to identify studies reporting BRAF mutation in thyroid neoplasms. Pooled prevalence, histopathological subtype distribution, extrathyroidal extension, lymph node metastasis, recurrence, and survival were extracted/analyzed from 32 studies (13 191 patients).

RESULTS

In the COSMIC database, BRAF K601E was found in various tissue types but mainly in the thyroid. In silico data analysis revealed a structural and functional basis for differences between K601E and V600E. Upon systematic review, the BRAF K601E mutation was identified in 2.8% of PTCs compared to 22% with V600E. The stratified analysis revealed geographical differences, with higher rates in Italy (5.23%) and the United States of America (3.31%). The K601E mutant was enriched for follicular-patterned variants like NIFTP (11.2% of cases). Meta-analysis demonstrated significantly reduced extrathyroidal extension for K601E versus V600E mutants (RR = 0.22, 95% CI = 0.10-0.50, p = 0.0003).

CONCLUSION

K601E-mutated neoplasms could be a unique clinicopathological entity associated with low-risk histology and reduced extrathyroidal extension, consistent with a more indolent course than V600E mutants. Although detecting K601E may potentially guide conservative management, further prospective studies are needed.

A protein expression atlas on tissue samples and cell lines from cancer patients provides insights into tumor heterogeneity and dependencies

The Cancer Genome Atlas (TCGA) and the Cancer Cell Line Encyclopedia (CCLE) are foundational resources in cancer research, providing extensive molecular and phenotypic data. However, large-scale proteomic data across various cancer types for these cohorts remain limited. Here, we expand upon our previous work to generate high-quality protein expression data for approximately 8,000 TCGA patient samples and around 900 CCLE cell line samples, covering 447 clinically relevant proteins, using reverse-phase protein arrays. These protein expression profiles offer profound insights into intertumor heterogeneity and cancer dependency and serve as sensitive functional readouts for somatic alterations. We develop a systematic protein-centered strategy for identifying synthetic lethality pairs and experimentally validate an interaction between protein kinase A subunit α and epidermal growth factor receptor. We also identify metastasis-related protein markers with clinical relevance. This dataset represents a valuable resource for advancing our understanding of cancer mechanisms, discovering protein biomarkers and developing innovative therapeutic strategies.

Mediating kinase activity in Ras-mutant cancer: potential for an individualised approach?

It is widely acknowledged that there is a considerable number of oncogenic mutations within the Ras superfamily of small GTPases which are the driving force behind a multitude of cancers. Ras proteins mediate a plethora of kinase pathways, including the MAPK, PI3K, and Ral pathways. Since Ras was considered undruggable until recently, pharmacological targeting of pathways downstream of Ras has been attempted to varying success, though drug resistance has often proven an issue. Nuances between kinase pathway activation in the presence of various Ras mutants are thought to contribute to the resistance, however, the reasoning behind activation of different pathways in different Ras mutational contexts is yet to be fully elucidated. Indeed, such disparities often depend on cancer type and disease progression. However, we are in a revolutionary age of Ras mutant targeted therapy, with direct-targeting KRAS-G12C inhibitors revolutionising the field and achieving FDA-approval in recent years. However, these are only beneficial in a subset of patients. Approximately 90% of Ras-mutant cancers are not KRAS-G12C mutant, and therefore raises the question as to whether other distinct amino acid substitutions within Ras may one day be targetable in a similar manner, and indeed whether better understanding of the downstream pathways these various mutants activate could further improve therapy. Here, we discuss the favouring of kinase pathways across an array of Ras-mutant oncogenic contexts and assess recent advances in pharmacological targeting of various Ras mutants. Ultimately, we will examine the utility of individualised pharmacological approaches to Ras-mediated cancer.

Traditional Chinese herbal medicine: harnessing dendritic cells for anti-tumor benefits

Chinese Herbal Medicine (CHM) is being more and more used in cancer treatment because of its ability to regulate the immune system. Chinese Herbal Medicine has several advantages over other treatment options, including being multi-component, multi-target, and having fewer side effects. Dendritic cells (DCs) are specialized antigen presenting cells that play a vital part in connecting the innate and adaptive immune systems. They are also important in immunotherapy. Recent evidence suggests that Chinese Herbal Medicine and its components can positively impact the immune response by targeting key functions of dendritic cells. In this review, we have summarized the influences of Chinese Herbal Medicine on the immunobiological feature of dendritic cells, emphasized an anti-tumor effect of CHM-treated DCs, and also pointed out deficiencies in the regulation of DC function by Chinese Herbal Medicine and outlined future research directions.

First line therapy in stage IV BRAF mutated colorectal cancer

Introduction

The molecular profile of colorectal cancer (CRC) plays a crucial role in understanding patient prognosis and treatment response. Within CRC, a distinct subgroup can be identified by the presence of the BRAF V600E mutation. This specific mutation, classified as Class I of BRAF mutations, is known to be associated with a poor prognosis and resistance to standard therapy. To determine the most effective treatment approach for this specific subgroup of CRC, we conducted a network meta-analysis (NMA) to compare various pharmacological interventions and evaluate their relative effectiveness in BRAF-mutated CRCs.

Materials and methods

On July 31, 2023, we conducted a systematic search of PubMed, Cochrane Central Register of Controlled Trials, and Embase. The inclusion criteria were as follows: 1) reporting of outcomes in patients with BRAF-mutated CRC who underwent first-line chemotherapy; 2) reporting of survival information as hazard ratios (HR); and 3) publication in English. The data were combined using HRs for overall and progression-free survival (OS and PFS) using random-effects models. NMA was performed under the Bayesian framework, utilizing the GeMTC package. The relative rankings of the treatments were determined using SUCRA scores.

Results

A total of 16 studies were included. When compared to standard chemotherapy (CT) doublets (such as FOLFOX or FOLFIRI), none of the comparison arms demonstrated a gain in OS. CT doublet + bevacizumab did not show significant superiority over either CT doublet alone or 5FU/capecitabine + bevacizumab. FOLFOXIRI and FOLFOXIRI + bevacizumab did not show superiority over any other treatment schedule that was compared. CT doublets + bevacizumab had the highest SUCRA score (0.87), followed by single-agent fluoropyrimidines + bevacizumab (0.61), and FOLFOXIRI (0.56). Regarding PFS, no regimen was found to be superior to the combination of CT doublet plus bevacizumab. However, FOLFOXIRI + bevacizumab + atezolizumab showed a tendency towards better results (HR = 0.26, 95 % CI 0.05-1.1).

Conclusions

Our review suggests that a CT doublet with bevacizumab is the most favorable option for OS. However, a reasonable alternative could be a triplet CT without bevacizumab.

An overview of RAF kinases and their inhibitors (2019-2023)

Protein kinases (PKs) including RAF, perform a principal role in regulating countless cellular events such as cell growth, differentiation, and angiogenesis. Overexpression and mutation of RAF kinases are significant contributors to the development and spread of cancer. Therefore, RAF kinase inhibitors show promising outcomes as anti-cancer small molecules by suppressing the expression of RAF protein, blocking RAS/RAF interaction, or inhibiting RAF enzymes. Currently, there are insufficient reports about approving drugs with minimal degree of toxicity. Therefore, it is an urgent need to develop new RAF kinase inhibitors correlated with increased anticancer activity and lower cytotoxicity. This review outlines reported RAF kinase inhibitors for cancer treatment in patents and literature from 2019 to 2023. It highlights the available inhibitors by shedding light on their chemical structures, biochemical profiles, and current status. Additionally, we highlighted the hinge region-binding moiety of the reported compounds by showing the hydrogen bond patterns of representative inhibitors with the hinge region for each class. In recent years, RAF kinase inhibitors have gained considerable attention in cancer research and drug development due to their potential to be studied under clinical trials and their demonstration of various degrees of efficacy and safety profiles across different cancer types. However, addressing challenges related to drug resistance and safety represents a major avenue for the optimization and enhancement of RAF kinase inhibitors. Strategies to overcome such obstacles were discussed such as developing novel pan-RAF inhibitors, RAF dimer inhibitors, and combination treatments.

Tumor-Agnostic Genomic and Clinical Analysis of BRAF Fusions Identifies Actionable Targets

PURPOSE

Even though BRAF fusions are increasingly detected in standard multigene next-generation sequencing panels, few reports have explored their structure and impact on clinical course.

EXPERIMENTAL DESIGN

We collected data from patients with BRAF fusion-positive cancers identified through a genotyping protocol of 97,024 samples. Fusions were characterized and reviewed for oncogenic potential (in-frame status, non-BRAF partner gene, and intact BRAF kinase domain).

RESULTS

We found 241 BRAF fusion-positive tumors from 212 patients with 82 unique 5' fusion partners spanning 52 histologies. Thirty-nine fusion partners were not previously reported, and 61 were identified once. BRAF fusion incidence was enriched in pilocytic astrocytomas, gangliogliomas, low-grade neuroepithelial tumors, and acinar cell carcinoma of the pancreas. Twenty-four patients spanning multiple histologies were treated with MAPK-directed therapies, of which 20 were evaluable for RECIST. Best response was partial response (N = 2), stable disease (N = 11), and progressive disease (N = 7). The median time on therapy was 1 month with MEK plus BRAF inhibitors [(N = 11), range 0-18 months] and 8 months for MEK inhibitors [(N = 14), range 1-26 months]. Nine patients remained on treatment for longer than 6 months [pilocytic astrocytomas (N = 6), Erdheim-Chester disease (N = 1), extraventricular neurocytoma (N = 1), and melanoma (N = 1)]. Fifteen patients had acquired BRAF fusions.

CONCLUSIONS

BRAF fusions are found across histologies and represent an emerging actionable target. BRAF fusions have a diverse set of fusion partners. Durable responses to MAPK therapies were seen, particularly in pilocytic astrocytomas. Acquired BRAF fusions were identified after targeted therapy, underscoring the importance of postprogression biopsies to optimize treatment at relapse in these patients.

Encorafenib plus binimetinib for BRAF V600E-mutant metastatic NSCLC: clinical implications of the phase 2 PHAROS study

Drs. Ramalingam and Carlisle discuss the incidence and pathophysiology of BRAF V600E-mutant metastatic non-small cell lung cancer and current treatment options. The podcast provides an overview of the data from the recent Pfizer-sponsored phase 2 PHAROS (NCT03915951) study, which were the basis for the recent US Food and Drug Administration approval of encorafenib plus binimetinib for BRAF V600E-mutant metastatic non-small cell lung cancer.

Molecular characterization of Chinese patients with small bowel adenocarcinoma

PURPOSE

Small bowel adenocarcinoma (SBA) is a rare malignancy of the gastrointestinal tract, and its unique location within the small intestine presents difficulties in obtaining tissue samples from the lesions. This limitation hinders the research and development of effective clinical treatment methods. Circulating tumor DNA (ctDNA) analysis holds promise as an alternative approach for investigating SBA and guiding treatment decisions, thereby improving the prognosis of SBA.

METHODS

Between January 2017 and August 2021, a total of 336 tissue or plasma samples were obtained and the corresponding mutation status in tissue or blood was evaluated with NGS.

RESULTS AND CONCLUSIONS

The study found that in SBA tissues, the most commonly alternated genes were TP53, KRAS, and APC, and the most frequently affected pathways were RTK-RAS-MAPK, TP53, and WNT. Notably, the RTK-RAS-MAPK pathway was identified as a potential biomarker that could be targeted for treatment. Then, we validated the gene mutation profiling of ctDNA extracted from SBA patients exhibited the same characteristics as tissue samples for the first time. Subsequently, we applied ctDNA analysis on a terminal-stage patient who had shown no response to previous chemotherapy. After detecting alterations in the RTK-RAS-MAPK pathway in the ctDNA, the patient was treated with MEK + EGFR inhibitors and achieved a tumor shrinkage rate of 76.33%. Our study utilized the largest Chinese SBA cohort to uncover the molecular characteristics of this disease, which might facilitate clinical decision making for SBA patients.

Molecular and morphologic characterization of intraductal tubulopapillary neoplasms of pancreas with novel potentially targetable fusions

Intraductal tubulopapillary neoplasms (ITPNs) are rare pancreatic tumors with distinct histological and molecular features. Distinction of ITPN from other pancreatic neoplasms is crucial given the known favorable prognosis and the high frequency and diversity of potentially targetable fusions in ITPN. While the histological features of ITPN are well documented, there are few reports on the cytological features, and molecular characterization of ITPN. The authors reported three cases diagnosed in their laboratory between 2016 and 2021. Clinical data, cytomorphological and histological features, with immunophenotypic and molecular characterizations of these cases are described and compared with those reported in the literature. All 3 cases were diagnosed as ITPN based on the microscopic presence of intraductal nodules composed of tightly packed small tubular glands lined by cuboidal cells lacking apparent mucin. On molecular profiling KRAS and TP53 variants were found in Case 1, FGFR2-INA fusion in Case 2, and STARD3NL-BRAF fusion was detected in Case 3. Immunohistochemistry (IHC) revealed that the neoplastic cells in Case 1 were MUC2 positive and MUC6 negative, but in Cases 2 and 3, were negative for MUC2 and positive for MUC6. These results demonstrate the immunophenotypic and molecular variabilities of histologically similar pancreatic neoplasms. The absence of alterations characteristic of more common pancreatic neoplasms should prompt the consideration of fusion studies in morphologically relevant cases. The combination of morphological, IHC, and molecular analyses is important for reliable identification of ITPN given its potential clinical management implications.

Somatic Mutation Profile as a Predictor of Treatment Response and Survival in Unresectable Pancreatic Ductal Adenocarcinoma Treated with FOLFIRINOX and Gemcitabine Nab-Paclitaxel

(1) Background: Pancreatic ductal adenocarcinoma (PDAC) has low survival rates despite treatment advancements. Aim: This study aims to show how molecular profiling could possibly guide personalized treatment strategies, which may help improve survival outcomes in patients with PDAC. (2) Materials and Methods: A retrospective analysis of 142 PDAC patients from a single academic center was conducted. Patients underwent chemotherapy and next-generation sequencing for molecular profiling. Key oncogenic pathways were identified using the Reactome pathway database. Survival analysis was performed using Kaplan-Meier curves and Cox Proportional Hazards Regression. (3) Results: Patients mainly received FOLFIRINOX (n = 62) or gemcitabine nab-paclitaxel (n = 62) as initial chemotherapy. The median OS was 13.6 months. Longer median OS was noted in patients with NOTCH (15 vs. 12.3 months, p = 0.007) and KIT pathway mutations (21.3 vs. 12.12 months, p = 0.04). Combinatorial pathway analysis indicated potential synergistic effects on survival. In the PFS, PI3K pathway (6.6 vs. 5.7 months, p = 0.03) and KIT pathway (10.3 vs. 6.2 months, p = 0.03) mutations correlated with improved PFS within the gemcitabine nab-paclitaxel subgroup. (4) Conclusions: Molecular profiling could play a role in PDAC for predicting outcomes and responses to therapies like FOLFIRINOX and gemcitabine nab-paclitaxel. Integrating genomic data into clinical decision-making can benefit PDAC treatment, though further validation is needed to fully utilize precision oncology in PDAC management.

Regorafenib in patients with pretreated advanced melanoma: a single-center case series

Melanoma patients failing all approved treatment options have a poor prognosis. The antimelanoma activity of regorafenib (REGO), a multitargeted kinase inhibitor, has not been investigated in this patient population. The objective response rate and safety of REGO treatment in advanced melanoma patients was investigated retrospectively. Twenty-seven patients received REGO treatment. All patients had progressed on anti-programmed cell death protein 1 (PD-1) and anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) checkpoint inhibition and BRAF/MEK inhibitors (in case of a BRAF V600 mutation). REGO was administered in continuous dosing and combined (upfront or sequentially) with nivolumab ( n  = 5), trametinib ( n  = 8), binimetinib ( n  = 2), encorafenib ( n  = 1), dabrafenib/trametinib ( n  = 9), or encorafenib/binimetinib ( n  = 7). The best overall response was partial response (PR) in five patients (18.5%) and stable disease in three patients (11.1%). Three of seven (42.8%) BRAF  V600mut patients treated with REGO in combination with BRAF/MEK inhibitors obtained a PR (including regression of brain metastases in all three patients). In addition, PR was documented in a BRAF V600mut patient treated with REGO plus anti-PD-1, and a NRASQ61mut patient treated with REGO plus a MEK inhibitor. Common grade 3-4 treatment-related adverse events included arterial hypertension ( n  = 7), elevated transaminase levels ( n  = 5), abdominal pain ( n  = 3), colitis ( n  = 2), anorexia ( n  = 1), diarrhea ( n  = 1), fever ( n  = 1), duodenal perforation ( n  = 1), and colonic bleeding ( n  = 1). Median progression-free survival was 11.0 weeks (95% confidence interval, 7.1-14.9); median overall survival was 23.1 weeks (95% confidence interval, 13.0-33.3). REGO has a manageable safety profile in advanced melanoma patients, in monotherapy as well as combined with BRAF/MEK inhibitors or PD-1 blocking monoclonal antibodies. The triplet combination of REGO with BRAF/MEK inhibitors appears most active, particularly in the BRAF V600mut patients.

Systematic loss-of-function screens identify pathway-specific functional circular RNAs

Circular RNA (circRNA) is covalently closed, single-stranded RNA produced by back-splicing. A few circRNAs have been implicated as functional; however, we lack understanding of pathways that are regulated by circRNAs. Here we generated a pooled short-hairpin RNA library targeting the back-splice junction of 3,354 human circRNAs that are expressed at different levels (ranging from low to high) in humans. We used this library for loss-of-function proliferation screens in a panel of 18 cancer cell lines from four tissue types harbouring mutations leading to constitutive activity of defined pathways. Both context-specific and non-specific circRNAs were identified. Some circRNAs were found to directly regulate their precursor, whereas some have a function unrelated to their precursor. We validated these observations with a secondary screen and uncovered a role for circRERE(4-10) and circHUWE1(22,23), two cell-essential circRNAs, circSMAD2(2-6), a WNT pathway regulator, and circMTO1(2,RI,3), a regulator of MAPK signalling. Our work sheds light on pathways regulated by circRNAs and provides a catalogue of circRNAs with a measurable function.

Tovorafenib: First Approval

Tovorafenib (OJEMDA™) is a once-weekly oral, selective, brain-penetrant, type II RAF kinase inhibitor being developed by Day One Biopharmaceuticals, Inc., under a license from Takeda Oncology, for the treatment of paediatric low-grade glioma (pLGG) and solid tumours. Most pLGGs harbour alterations in the MAPK pathway, such as a BRAF mutation or BRAF fusion, which result in aberrant intracellular signalling. Tovorafenib is an inhibitor of mutant BRAF V600E, wild-type BRAF and wild-type CRAF kinases and BRAF fusions. In April 2024, tovorafenib received its first approval in the USA for the treatment of patients aged ≥ 6 months with relapsed or refractory pLGGs harbouring a BRAF fusion or rearrangement, or BRAF V600 mutation. It received accelerated approval for this indication based on the response rate and duration of response achieved in this population in the ongoing, pivotal, phase 2 FIREFLY-1 study. Clinical development of tovorafenib is underway in numerous countries worldwide. This article summarizes the milestones in the development of tovorafenib leading to this first approval for relapsed or refractory pLGG with an activating BRAF alteration.

Tunlametinib: First Approval

Tunlametinib (®) is an oral, selective, mitogen-activated protein kinase kinase 1 and 2 (MEK 1/2) inhibitor being developed by Shanghai KeChow Pharma, Inc. for the treatment of solid tumours with RAS and RAF mutations, including melanoma, non-small cell cancer (NSCLC), colorectal cancer (CRC) and neurofibromatosis type 1 (NF1) plexiform neurofibromas. In March 2024, tunlametinib was granted conditional approval in China (based on surrogate endpoints) for use in patients with NRAS-mutated advanced melanoma who have failed anti-PD-1/PD-L1 treatment. This article summarizes the milestones in the development of tunlametinib leading to this first approval for the treatment of solid tumours with RAS and RAF mutations.

Signaling from RAS to RAF: The Molecules and Their Mechanisms

RAF family protein kinases are a key node in the RAS/RAF/MAP kinase pathway, the signaling cascade that controls cellular proliferation, differentiation, and survival in response to engagement of growth factor receptors on the cell surface. Over the past few years, structural and biochemical studies have provided new understanding of RAF autoregulation, RAF activation by RAS and the SHOC2 phosphatase complex, and RAF engagement with HSP90-CDC37 chaperone complexes. These studies have important implications for pharmacologic targeting of the pathway. They reveal RAF in distinct regulatory states and show that the functional RAF switch is an integrated complex of RAF with its substrate (MEK) and a 14-3-3 dimer. Here we review these advances, placing them in the context of decades of investigation of RAF regulation. We explore the insights they provide into aberrant activation of the pathway in cancer and RASopathies (developmental syndromes caused by germline mutations in components of the pathway).

Reverse repurposing: Potential utility of cancer drugs in nonmalignant illnesses

Growth and immune process dysregulation can result in both cancer and nonmalignant disease (hereditary or acquired, with and without predisposition to malignancy). Moreover, perhaps unexpectedly, many nonmalignant illnesses harbor genomic alterations indistinguishable from druggable oncogenic drivers. Therefore, targeted compounds used successfully to treat cancer may have therapeutic potential for nonmalignant conditions harboring the same target. MEK, PI3K/AKT/mTOR, fibroblast growth factor receptor (FGFR), and NRG1/ERBB pathway genes have all been implicated in both cancer and noncancerous conditions, and several cognate antagonists, as well as Bruton's tyrosine kinase inhibitors, JAK inhibitors, and CD20-directed antibodies, have established or theoretical therapeutic potential to bridge cancer and benign diseases. Intriguingly, pharmacologically tractable cancer drivers characterize a wide spectrum of disorders without malignant potential, including but not limited to Alzheimer's disease and a variety of other neurodegenerative conditions, rheumatoid arthritis, achondroplastic dwarfism, and endometriosis. Expanded repositioning of oncology agents in order to benefit benign but serious medical illnesses is warranted.

Efficacy-effectiveness analysis on survival in a population-based real-world study of BRAF-mutated metastatic colorectal cancer patients treated with encorafenib-cetuximab

BACKGROUND

Encorafenib-cetuximab has been approved for pretreated BRAFV600E-mutated metastatic colorectal cancer (mCRC) patients based on efficacy demonstrated in the randomized phase III BEACON trial. The aim of this real-world effectiveness study is to improve knowledge on the generalizability of trial results.

METHODS

This population-based real-world study includes all mCRC patients in the Netherlands treated with encorafenib-cetuximab since approval. Individual patient data and pathology reports were collected. Overall survival (OS) was compared to BEACON and subgroup analyses were conducted for patients who would have been eligible and ineligible for BEACON.

RESULTS

166 patients were included with a median follow-up time of 14.5 months. Median OS was 6.7 months (95% CI:6.0-8.3) and differed from BEACON (9.3 months; 95% CI:8.0-11.3, p-value 0.002). Thirty-six percent of real-world patients would have been ineligible for the BEACON trial. Trial ineligible subgroups with symptomatic brain metastases and WHO performance status ≥2 had the poorest median OS of 5.0 months (95% CI:4.0-NR) and 3.9 months (95% CI:2.4-NR).

CONCLUSION

This real-world cohort of mCRC patients treated with encorafenib-cetuximab showed a clinically relevant efficacy-effectiveness gap for OS. The chance of survival benefit from encorafenib-cetuximab in patients with brain metastases and/or WHO performance status ≥2 is negligible as neither efficacy nor effectiveness has been demonstrated.

The Pan-RAF-MEK Nondegrading Molecular Glue NST-628 Is a Potent and Brain-Penetrant Inhibitor of the RAS-MAPK Pathway with Activity across Diverse RAS- and RAF-Driven Cancers

Alterations in the RAS-MAPK signaling cascade are common across multiple solid tumor types and are a driver for many cancers. NST-628 is a potent pan-RAF-MEK molecular glue that prevents the phosphorylation and activation of MEK by RAF, overcoming the limitations of traditional RAS-MAPK inhibitors and leading to deep durable inhibition of the pathway. Cellular, biochemical, and structural analyses of RAF-MEK complexes show that NST-628 engages all isoforms of RAF and prevents the formation of BRAF-CRAF heterodimers, a differentiated mechanism from all current RAF inhibitors. With a potent and durable inhibition of the RAF-MEK signaling complex as well as high intrinsic permeability into the brain, NST-628 demonstrates broad efficacy in cellular and patient-derived tumor models harboring diverse MAPK pathway alterations, including orthotopic intracranial models. Given its functional and pharmacokinetic mechanisms that are differentiated from previous therapies, NST-628 is positioned to make an impact clinically in areas of unmet patient need. Significance: This study introduces NST-628, a molecular glue having differentiated mechanism and drug-like properties. NST-628 treatment leads to broad efficacy with high tolerability and central nervous system activity across multiple RAS- and RAF-driven tumor models. NST-628 has the potential to provide transformative clinical benefits as both monotherapy and vertical combination anchor.

A Practical Review of Encorafenib and Binimetinib Therapy Management in Patients with BRAF V600E-Mutant Metastatic Non-Small Cell Lung Cancer

According to current guidelines, targeted therapy with a combination of BRAF plus MEK inhibitors is the preferred first-line treatment for patients with BRAF V600E-mutant metastatic non-small cell lung cancer (NSCLC). In the open-label, single-arm, phase 2 PHAROS trial (NCT03915951), the combination of encorafenib, a potent BRAF inhibitor, and binimetinib, a potent MEK inhibitor, demonstrated durable antitumor activity with a manageable safety profile in this patient population. On the basis of the results of this study, the combination of encorafenib plus binimetinib was approved by the US Food and Drug Administration on October 11, 2023, for patients with BRAF V600E-mutant metastatic NSCLC. In this review, we summarize the efficacy and safety of encorafenib plus binimetinib from the PHAROS study. In addition, we discuss strategies to manage adverse reactions with this combination therapy with the intent of minimizing unnecessary treatment discontinuations in these patients.

FAK loss reduces BRAFV600E-induced ERK phosphorylation to promote intestinal stemness and cecal tumor formation

BRAFV600E mutation is a driver mutation in the serrated pathway to colorectal cancers. BRAFV600E drives tumorigenesis through constitutive downstream extracellular signal-regulated kinase (ERK) activation, but high-intensity ERK activation can also trigger tumor suppression. Whether and how oncogenic ERK signaling can be intrinsically adjusted to a 'just-right' level optimal for tumorigenesis remains undetermined. In this study, we found that FAK (Focal adhesion kinase) expression was reduced in BRAFV600E-mutant adenomas/polyps in mice and patients. In Vil1-Cre;BRAFLSL-V600E/+;Ptk2fl/fl mice, Fak deletion maximized BRAFV600E's oncogenic activity and increased cecal tumor incidence to 100%. Mechanistically, our results showed that Fak loss, without jeopardizing BRAFV600E-induced ERK pathway transcriptional output, reduced EGFR (epidermal growth factor receptor)-dependent ERK phosphorylation. Reduction in ERK phosphorylation increased the level of Lgr4, promoting intestinal stemness and cecal tumor formation. Our findings show that a 'just-right' ERK signaling optimal for BRAFV600E-induced cecal tumor formation can be achieved via Fak loss-mediated downregulation of ERK phosphorylation.

Off-target autophagy inhibition by SHP2 allosteric inhibitors contributes to their antitumor activity in RAS-driven cancers

Aberrant activation of RAS/MAPK signaling is common in cancer, and efforts to inhibit pathway components have yielded drugs with promising clinical activities. Unfortunately, treatment-provoked adaptive resistance mechanisms inevitably develop, limiting their therapeutic potential. As a central node essential for receptor tyrosine kinase-mediated RAS activation, SHP2 has emerged as an attractive cancer target. Consequently, many SHP2 allosteric inhibitors are now in clinical testing. Here we discovered a previously unrecognized off-target effect associated with SHP2 allosteric inhibitors. We found that these inhibitors accumulate in the lysosome and block autophagic flux in an SHP2-independent manner. We showed that off-target autophagy inhibition by SHP2 allosteric inhibitors contributes to their antitumor activity. We also demonstrated that SHP2 allosteric inhibitors harboring this off-target activity not only suppress oncogenic RAS signaling but also overcome drug resistance such as MAPK rebound and protective autophagy in response to RAS/MAPK pathway blockage. Finally, we exemplified a therapeutic framework that harnesses both the on- and off-target activities of SHP2 allosteric inhibitors for improved treatment of mutant RAS-driven and drug-resistant malignancies such as pancreatic and colorectal cancers.

State of the Art in Low-Grade Glioma Management: Insights From Isocitrate Dehydrogenase and Beyond

Low-grade gliomas present a formidable challenge in neuro-oncology because of the challenges imposed by the blood-brain barrier, predilection for the young adult population, and propensity for recurrence. In the past two decades, the systematic examination of genomic alterations in adults and children with primary brain tumors has uncovered profound new insights into the pathogenesis of these tumors, resulting in more accurate tumor classification and prognostication. It also identified several common recurrent genomic alterations that now define specific brain tumor subtypes and have provided a new opportunity for molecularly targeted therapeutic intervention. Adult-type diffuse low-grade gliomas are frequently associated with mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2), resulting in production of 2-hydroxyglutarate, an oncometabolite important for tumorigenesis. Recent studies of IDH inhibitors have yielded promising results in patients at early stages of disease with prolonged progression-free survival (PFS) and delayed time to radiation and chemotherapy. Pediatric-type gliomas have high rates of alterations in BRAF, including BRAF V600E point mutations or BRAF-KIAA1549 rearrangements. BRAF inhibitors, often combined with MEK inhibitors, have resulted in radiographic response and improved PFS in these patients. This article reviews emerging approaches to the treatment of low-grade gliomas, including a discussion of targeted therapies and how they integrate with the current treatment modalities of surgical resection, chemotherapy, and radiation.

Novel RAF-directed approaches to overcome current clinical limits and block the RAS/RAF node

Mutations in the RAS-RAF-MEK-ERK pathway are frequent alterations in cancer and RASopathies, and while RAS oncogene activation alone affects 19% of all patients and accounts for approximately 3.4 million new cases every year, less frequent alterations in the cascade's downstream effectors are also involved in cancer etiology. RAS proteins initiate the signaling cascade by promoting the dimerization of RAF kinases, which can act as oncoproteins as well: BRAFV600E is the most common oncogenic driver, mutated in the 8% of all malignancies. Research in this field led to the development of drugs that target the BRAFV600-like mutations (Class I), which are now utilized in clinics, but cause paradoxical activation of the pathway and resistance development. Furthermore, they are ineffective against non-BRAFV600E malignancies that dimerize and could be either RTK/RAS independent or dependent (Class II and III, respectively), which are still lacking an effective treatment. This review discusses the recent advances in anti-RAF therapies, including paradox breakers, dimer-inhibitors, immunotherapies, and other novel approaches, critically evaluating their efficacy in overcoming the therapeutic limitations, and their putative role in blocking the RAS pathway.

Immunotherapy: A Sharp Curve Turn at the Corner of Targeted Therapy in the Treatment of Biliary Tract Cancers

Biliary tract cancers continue to increase in incidence and have a high mortality rate. Most of the patients present with advanced-stage disease. The discovery of targetable genomic alterations addressing IDH, FGFR, HER2, BRAFV600 E, and others has led to the identification and validation of novel therapies in biliary cancer. Recent advances demonstrating an improved outcome with the addition of immune checkpoint inhibitors to chemotherapy have established a new first-line care standard. In case of contraindications to the use of checkpoint inhibitors and the absence of targetable alterations, chemotherapy remains to be the standard of care.

Cupric-polymeric nanoreactors integrate into copper metabolism to promote chronic diabetic wounds healing

Given multifunction of copper (Cu) contributing to all stages of the physiology of wound healing, Cu-based compounds have great therapeutic potentials to accelerate the wound healing, but they must be limited to a very low concentration range to avoid detrimental accumulation. Additionally, the cellular mechanism of Cu-based compounds participating the healing process remains elusive. In this study, copper oxide nanoparticles (CuONPs) were synthesized to mimic the multiple natural enzymes and trapped into PEG-b-PCL polymersomes (PS) to construct cupric-polymeric nanoreactors (CuO@PS) via a direct hydration method, thus allowing to compartmentalize Cu-based catalytic reactions in an isolated space to improve the efficiency, selectivity, recyclability as well as biocompatibility. While nanoreactors trafficked to lysosomes following endocytosis, the released Cu-based compounds in lysosomal lumen drove a cytosolic Cu+ influx to mobilize Cu metabolism mostly via Atox1-ATP7a/b-Lox axis, thereby activating the phosphorylation of mitogen-activated protein kinase 1 and 2 (MEK1/2) to initiate downstream signaling events associated with cell proliferation, migration and angiogenesis. Moreover, to facilitate to lay on wounds, cupric-polymeric nanoreactors were finely dispersed into a thermosensitive Pluronic F127 hydrogel to form a composite hydrogel sheet that promoted the healing of chronic wounds in diabetic rat models. Hence, cupric-polymeric nanoreactors represented an attractive translational strategy to harness cellular Cu metabolism for chronic wounds healing.

Targeting RAF dimers in RAS mutant tumors: From biology to clinic

RAS mutations occur in approximately 30% of tumors worldwide and have a poor prognosis due to limited therapies. Covalent targeting of KRAS G12C has achieved significant success in recent years, but there is still a lack of efficient therapeutic approaches for tumors with non-G12C KRAS mutations. A highly promising approach is to target the MAPK pathway downstream of RAS, with a particular focus on RAF kinases. First-generation RAF inhibitors have been authorized to treat BRAF mutant tumors for over a decade. However, their use in RAS-mutated tumors is not recommended due to the paradoxical ERK activation mainly caused by RAF dimerization. To address the issue of RAF dimerization, type II RAF inhibitors have emerged as leading candidates. Recent clinical studies have shown the initial effectiveness of these agents against RAS mutant tumors. Promisingly, type II RAF inhibitors in combination with MEK or ERK inhibitors have demonstrated impressive efficacy in RAS mutant tumors. This review aims to clarify the importance of RAF dimerization in cellular signaling and resistance to treatment in tumors with RAS mutations, as well as recent progress in therapeutic approaches to address the problem of RAF dimerization in RAS mutant tumors.

RAF and MEK Inhibitors in Non-Small Cell Lung Cancer

Lung cancer, despite recent advancements in survival rates, represents a significant global health burden. Non-small cell lung cancer (NSCLC), the most prevalent type, is driven largely by activating mutations in Kirsten rat sarcoma viral oncogene homologue (KRAS) and receptor tyrosine kinases (RTKs), and less in v-RAF murine sarcoma viral oncogene homolog B (BRAF) and mitogen-activated protein-kinase kinase (MEK), all key components of the RTK-RAS-mitogen-activated protein kinase (MAPK) pathway. Learning from melanoma, the identification of BRAFV600E substitution in NSCLC provided the rationale for the investigation of RAF and MEK inhibition as a therapeutic strategy. The regulatory approval of two RAF-MEK inhibitor combinations, dabrafenib-trametinib, in 2017, and encorafenib-binimetinib, in 2023, signifies a breakthrough for the management of BRAFV600E-mutant NSCLC patients. However, the almost universal emergence of acquired resistance limits their clinical benefit. New RAF and MEK inhibitors, with distinct biochemical characteristics, are in preclinical and clinical development. In this review, we aim to provide valuable insights into the current state of RAF and MEK inhibition in the management of NSCLC, fostering a deeper understanding of the potential impact on patient outcomes.

Disruption of the pro-oncogenic c-RAF-PDE8A complex represents a differentiated approach to treating KRAS-c-RAF dependent PDAC

Pancreatic ductal adenocarcinoma (PDAC) is considered the third leading cause of cancer mortality in the western world, offering advanced stage patients with few viable treatment options. Consequently, there remains an urgent unmet need to develop novel therapeutic strategies that can effectively inhibit pro-oncogenic molecular targets underpinning PDACs pathogenesis and progression. One such target is c-RAF, a downstream effector of RAS that is considered essential for the oncogenic growth and survival of mutant RAS-driven cancers (including KRASMT PDAC). Herein, we demonstrate how a novel cell-penetrating peptide disruptor (DRx-170) of the c-RAF-PDE8A protein-protein interaction (PPI) represents a differentiated approach to exploiting the c-RAF-cAMP/PKA signaling axes and treating KRAS-c-RAF dependent PDAC. Through disrupting the c-RAF-PDE8A protein complex, DRx-170 promotes the inactivation of c-RAF through an allosteric mechanism, dependent upon inactivating PKA phosphorylation. DRx-170 inhibits cell proliferation, adhesion and migration of a KRASMT PDAC cell line (PANC1), independent of ERK1/2 activity. Moreover, combining DRx-170 with afatinib significantly enhances PANC1 growth inhibition in both 2D and 3D cellular models. DRx-170 sensitivity appears to correlate with c-RAF dependency. This proof-of-concept study supports the development of DRx-170 as a novel and differentiated strategy for targeting c-RAF activity in KRAS-c-RAF dependent PDAC.

BRAFV600E-mutant metastatic NSCLC: disease overview and treatment landscape

In this review, we cover the current understanding of BRAF mutations and associated clinical characteristics in patients with metastatic NSCLC, approved and emerging treatment options, BRAF sequencing approaches, and unmet needs. The BRAFV600E mutation confers constitutive activity of the MAPK pathway, leading to enhanced growth, proliferation, and survival of tumor cells. Testing for BRAF mutations enables patients to be treated with therapies that directly target BRAFV600E and the MAPK pathway, but BRAF testing lags behind other oncogene testing in metastatic NSCLC. Additional therapies targeting BRAFV600E mutations provide options for patients with metastatic NSCLC. Emerging therapies and combinations under investigation could potentially overcome issues of resistance and target non-V600E mutations. Therefore, because targeted therapies with enhanced efficacy are on the horizon, being able to identify BRAF mutations in metastatic NSCLC may become even more important.

KRAS and BRAF genetic alterations in lung cancer: A case - control study

CONTEXT

Lung cancer (LC) is one of the most critical neoplastic abnormalities, having globally a high mortality rate. Knowledge about its genetic mutations and their association with clinically pathological features of LC is very important. Here, we describe the epidemiological molecular study of genetic mutations in KRAS and BRAF genes and their relationship with the demographic and clinical characteristics of Pakistani patients with lung adenocarcinoma.

AIM

To analyze the mutations of KRAS and BRAF in LC patients among Pakistani population.

SETTINGS AND DESIGN

The study has been carried out at universities and health institutes of Islamabad, Pakistan.

METHODS AND MATERIAL

Deoxyribonucleic acid (DNA) was extracted from the patient samples by using the standard protocol and amplified by using the specific primers. Later on, the Polymerase Chain Reaction (PCR) products were examined with the help of single stranded conformational polymorphism (SSCP).

STATISTICAL ANALYSIS

Relationship between KRAS, BRAF mutations, and LC risk was accessed by conditional logistic regression using SPSS version 24.0. Results were illustrated by odds ratio (OR), 95% confidence interval (CI), and P value.

RESULTS

LC is more common in male population and smoking is one of the leading risk factors for (p < 0.0001) LC. KRAS and BRAF mutations were found to be contributing factors toward LC development and showed statistically significant results along with conformation through computational analysis.

CONCLUSIONS

It can be concluded that smoking is lethal and cancer causing. The concomitant mutations found in KRAS and BRAF were infrequent, and they probably have a very unusual effect on the clinical management of Pakistani patients with lung adenocarcinoma.

Case report: Primary sarcoma of the mandible with a novel SLMAP-BRAF fusion

Primary sarcomas of the jaw are very rare tumor with unclear mechanism of tumorigenesis. Identification of genetic alterations contributes to better understanding of tumorigenesis and extension of tumor spectrum, as well as potential therapeutic targets application. Herein, we firstly report a case of primary sarcoma in the mandible with novel SLMAP-BRAF fusion. Morphologically, the tumor was composed of histiocyte-like cells, larger epithelioid cells, spindle cells and osteoclast-like giant cells with moderate atypia. Focally, it mimicked tenosynovial giant cell tumor or biphasic synovial sarcoma, and even giant cell tumor of bone. SATB2 was diffusely expressed, while p63 and p16 were locally positive with loss expression of p16 in histiocyte-like and larger epithelioid cells. SLMAP-BRAF (S11:B10) fusion was detected by both DNA and RNA NGS, and further verified by sanger sequencing, DNA electrophoresis and FISH. Then a descriptive diagnosis of BRAF rearrangement sarcoma with moderate-grade malignancy (non-specific type) was given according to the biological behavior, morphological features and gene alteration. The patient finished six cycles of chemotherapy after hemimaxillectomy. Within 7 months of follow-up, no tumor recurrence or metastasis was observed. Our case has enriched the spectrum of jaw bone tumor and BRAF rearrangement tumor.

Live-cell target engagement of allosteric MEKi on MEK-RAF/KSR-14-3-3 complexes

The RAS-mitogen-activated protein kinase (MAPK) pathway includes KSR, RAF, MEK and the phospho-regulatory sensor 14-3-3. Specific assemblies among these components drive various diseases and likely dictate efficacy for numerous targeted therapies, including allosteric MEK inhibitors (MEKi). However, directly measuring drug interactions on physiological RAS-MAPK complexes in live cells has been inherently challenging to query and therefore remains poorly understood. Here we present a series of NanoBRET-based assays to quantify direct target engagement of MEKi on MEK1 and higher-order MEK1-bound complexes with ARAF, BRAF, CRAF, KSR1 and KSR2 in the presence and absence of 14-3-3 in living cells. We find distinct MEKi preferences among these complexes that can be compiled to generate inhibitor binding profiles. Further, these assays can report on the influence of the pathogenic BRAF-V600E mutant on MEKi binding. Taken together, these approaches can be used as a platform to screen for compounds intended to target specific complexes in the RAS-MAPK cascade.

Impact of tissue-agnostic approvals on management of primary brain tumors

Novel tissue-agnostic therapeutics targeting driver mutations in tumor cells have been recently approved by FDA, driven by basket trials that have demonstrated their efficacy and safety across diverse tumor histology. However, the relative rarity of primary brain tumors (PBTs) has limited their representation in early trials of tissue-agnostic medications. Thus, consensus continues to evolve regarding utility of tissue-agnostic medications in routine practice for PBTs, a diverse group of neoplasms characterized by limited treatment options and unfavorable prognoses. We describe current and potential impact of tissue-agnostic approvals on management of PBTs. We discuss data from clinical trials for PBTs regarding tissue-agnostic targets, including BRAFV600E, neurotrophic tyrosine receptor kinase (NTRK) fusions, microsatellite instability-high (MSI-High), mismatch repair deficiency (dMMR), and high tumor mutational burden (TMB-H), in context of challenges in managing PBTs. Described are additional tissue-agnostic targets that hold promise for benefiting patients with PBTs, including RET fusion, fibroblast growth factor receptor (FGFR), ERBB2/HER2, and KRASG12C, and TP53Y220C.

Small molecule agents for triple negative breast cancer: Current status and future prospects

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with poor prognosis. The number of cases increased by 2.26 million in 2020, making it the most commonly diagnosed cancer type in the world. TNBCs lack hormone receptor (HR) and human epidermal growth factor 2 (HER2), which limits treatment options. Currently, paclitaxel-based drugs combined with other chemotherapeutics remain the main treatment for TNBC. There is currently no consensus on the best therapeutic regimen for TNBC. However, there have been successful clinical trials exploring large-molecule monoclonal antibodies, small-molecule targeted drugs, and novel antibody-drug conjugate (ADC). Although monoclonal antibodies have produced clinical success, their large molecular weight can limit therapeutic benefits. It is worth noting that in the past 30 years, the FDA has approved small molecule drugs for HER2-positive breast cancers. The lack of effective targets and the occurrence of drug resistance pose significant challenges in the treatment of TNBC. To improve the prognosis of TNBC, it is crucial to search for effective targets and to overcome drug resistance. This review examines the clinical efficacy, adverse effects, resistance mechanisms, and potential solutions of targeted small molecule drugs in both monotherapies and combination therapies. New therapeutic targets, including nuclear export protein 1 (XPO1) and hedgehog (Hh), are emerging as potential options for researchers and become integrated into clinical trials for TNBC. Additionally, there is growing interest in the potential of targeted protein degradation chimeras (PROTACs), degraders of rogue proteins, as a future therapy direction. This review provides potentially valuable insights with clinical implications.

Adaptation of a mutual exclusivity framework to identify driver mutations within oncogenic pathways

Distinguishing genomic alterations in cancer-associated genes that have functional impact on tumor growth and disease progression from the ones that are passengers and confer no fitness advantage have important clinical implications. Evidence-based methods for nominating drivers are limited by existing knowledge on the oncogenic effects and therapeutic benefits of specific variants from clinical trials or experimental settings. As clinical sequencing becomes a mainstay of patient care, applying computational methods to mine the rapidly growing clinical genomic data holds promise in uncovering functional candidates beyond the existing knowledge base and expanding the patient population that could potentially benefit from genetically targeted therapies. We propose a statistical and computational method (MAGPIE) that builds on a likelihood approach leveraging the mutual exclusivity pattern within an oncogenic pathway for identifying probabilistically both the specific genes within a pathway and the individual mutations within such genes that are truly the drivers. Alterations in a cancer-associated gene are assumed to be a mixture of driver and passenger mutations with the passenger rates modeled in relationship to tumor mutational burden. We use simulations to study the operating characteristics of the method and assess false-positive and false-negative rates in driver nomination. When applied to a large study of primary melanomas, the method accurately identifies the known driver genes within the RTK-RAS pathway and nominates several rare variants as prime candidates for functional validation. A comprehensive evaluation of MAGPIE against existing tools has also been conducted leveraging the Cancer Genome Atlas data.

Atypical (non-V600E) BRAF mutations in metastatic colorectal cancer in population and real-world cohorts

BRAF-V600E mutation (mt) is a strong negative prognostic and predictive biomarker in metastatic colorectal cancer (mCRC). Non-V600Emt, designated atypical BRAFmt (aBRAFmt) are rare, and little is known about their frequency, co-mutations and prognostic and predictive role. These were compared between mutational groups of mCRC patients collected from three Nordic population-based or real-world cohorts. Pathology of aBRAFmt was studied. The study included 1449 mCRC patients with 51 (3%) aBRAFmt, 182 (13%) BRAF-V600Emt, 456 (31%) RAS&BRAF wild-type (wt) and 760 (52%) RASmt tumours. aBRAFmt were seen in 2% of real-world and 4% of population-based cohorts. Twenty-six different aBRAFmt were detected, 11 (22%) class 2 (serrated adenocarcinoma in 2/9 tested), 32 (64%) class 3 (serrated in 15/25) and 4 (8%) unclassified. aBRAFmt patients were predominantly male, had more rectal primaries, less peritoneal metastases, deficient mismatch repair in one (2%), and better survival after metastasectomy (89% 5-year overall survival [OS]-rate) compared with BRAF-V600Emt. aBRAFmt and BRAF-V600Emt had poorer performance status and received fewer treatment lines than RAS&BRAFwt and RASmt. OS among aBRAFmt (median 14.4 months) was longer than for BRAF-V600Emt (11.2 months), but shorter than for RAS&BRAFwt (30.5 months) and RASmt (23.4 months). Addition of bevacizumab trended for better OS for the aBRAFmt. Nine patients with aBRAFmt received cetuximab/panitumumab without response. aBRAFmt represents a distinct subgroup differing from other RAS/BRAF groups, with serrated adenocarcinoma in only half. OS for patients with aBRAFmt tumours was slightly better than for BRAF-V600Emt, but worse than for RASmt and RAS&BRAFwt. aBRAFmt should not be a contraindication for metastasectomy.

Natural products targeting the MAPK-signaling pathway in cancer: overview

PURPOSE

This article summarizes natural products that target the MAPK-signaling pathway in cancer therapy. The classification, chemical structures, and anti-cancer mechanisms of these natural products are elucidated, and comprehensive information is provided on their potential use in cancer therapy.

METHODS

Using the PubMed database, we searched for keywords, including "tumor", "cancer", "natural product", "phytochemistry", "plant chemical components", and "MAPK-signaling pathway". We also screened for compounds with well-defined structures that targeting the MAPK-signaling pathway and have anti-cancer effects. We used Kingdraw software and Adobe Photoshop software to draw the chemical compound structural diagrams.

RESULTS

A total of 131 papers were searched, from which 85 compounds with well-defined structures were selected. These compounds have clear mechanisms for targeting cancer treatment and are mainly related to the MAPK-signaling pathway. Examples include eupatilin, carvacrol, oridonin, sophoridine, diosgenin, and juglone. These chemical components are classified as flavonoids, phenols, terpenoids, alkaloids, steroidal saponins, and quinones.

CONCLUSIONS

Certain MAPK pathway inhibitors have been used for clinical treatment. However, the clinical feedback has not been promising because of genomic instability, drug resistance, and side effects. Natural products have few side effects, good medicinal efficacy, a wide range of sources, individual heterogeneity of biological activity, and are capable of treating disease from multiple targets. These characteristics make natural products promising drugs for cancer treatment.

FAK loss reduces BRAFV600E-induced ERK phosphorylation to promote intestinal stemness and cecal tumor formation

BRAF V600E mutation is a driver mutation in the serrated pathway to colorectal cancers. BRAFV600E drives tumorigenesis through constitutive downstream extracellular signal-regulated kinase (ERK) activation, but high-intensity ERK activation can also trigger tumor suppression. Whether and how oncogenic ERK signaling can be intrinsically adjusted to a "just-right" level optimal for tumorigenesis remains undetermined. In this study, we found that FAK (Focal adhesion kinase) expression was reduced in BRAFV600E-mutant adenomas/polyps in mice and patients. In Vill-Cre;BRAFV600E/+;Fakfl/fl mice, Fak deletion maximized BRAFV600E's oncogenic activity and increased cecal tumor incidence to 100%. Mechanistically, our results showed that Fak loss, without jeopardizing BRAFV600E-induced ERK pathway transcriptional output, reduced EGFR (epidermal growth factor receptor)-dependent ERK phosphorylation. Reduction in ERK phosphorylation increased the level of Lgr4, promoting intestinal stemness and cecal tumor formation. Our findings show that a "just-right" ERK signaling optimal for BRAFV600E-induced cecal tumor formation can be achieved via Fak loss-mediated downregulation of ERK phosphorylation.

FAK loss reduces BRAFV600E-induced ERK phosphorylation to promote intestinal stemness and cecal tumor formation

BRAF V600E mutation is a driver mutation in the serrated pathway to colorectal cancers. BRAFV600E drives tumorigenesis through constitutive downstream extracellular signal-regulated kinase (ERK) activation, but high-intensity ERK activation can also trigger tumor suppression. Whether and how oncogenic ERK signaling can be intrinsically adjusted to a "just-right" level optimal for tumorigenesis remains undetermined. In this study, we found that FAK (Focal adhesion kinase) expression was reduced in BRAFV600E-mutant adenomas/polyps in mice and patients. In Vill-Cre;BRAFV600E/+;Fakfl/fl mice, Fak deletion maximized BRAFV600E's oncogenic activity and increased cecal tumor incidence to 100%. Mechanistically, our results showed that Fak loss, without jeopardizing BRAFV600E-induced ERK pathway transcriptional output, reduced EGFR (epidermal growth factor receptor)-dependent ERK phosphorylation. Reduction in ERK phosphorylation increased the level of Lgr4, promoting intestinal stemness and cecal tumor formation. Our findings show that a "just-right" ERK signaling optimal for BRAFV600E-induced cecal tumor formation can be achieved via Fak loss-mediated downregulation of ERK phosphorylation.

PIWI-interacting RNA-YBX1 inhibits proliferation and metastasis by the MAPK signaling pathway via YBX1 in triple-negative breast cancer

Breast cancer is the second leading cause of death in women worldwide, with triple-negative breast cancer (TNBC) having the worst prognosis. Although there are numerous studies on TNBC, there is no effective treatment for it, and it is still a major problem today. Studies on PIWI-interacting RNAs (piRNAs) are increasing and investigating the mechanism of piRNAs in the proliferation and metastasis of TNBC may lead to new potential treatment targets. Here, we identified a novel piRNA, piR-YBX1, which was downregulated in TNBC compared to matched normal breast tissue. Overexpression of piR-YBX1 significantly inhibited the proliferation, migration, invasion ability of TNBC cells both in vivo and in vitro. Mechanistically, piR-YBX1 could bind directly to mRNA of Y-box binding protein 1 (YBX1) and overexpression of piR-YBX1 downregulated YBX1 in both mRNA and protein levels, while the function of piR-YBX1 could be partly rescued by overexpression of YBX1. In addition, YBX1 could bind to RAF1 which is the key molecule in the MAPK signaling pathway, and overexpression of piR-YBX1 inhibited the p-MEK and p-ERK1/2, which can be reverted by YBX1. In conclusion, our findings discovered that the piR-YBX1/YBX1/MAPK axis suppresses the proliferation and metastasis of TNBC and therefore piR-YBX1 has the potential to be an effective therapeutic agent for breast cancer.

HSPA8 Activates Wnt/β-Catenin Signaling to Facilitate BRAF V600E Colorectal Cancer Progression by CMA-Mediated CAV1 Degradation

BRAF V600E attracts wide attention in the treatment of colorectal cancer (CRC) as stratifying and predicting a refractory classification of CRC. Recent evidence indicates that Wnt/β-catenin signaling is broadly activated and participates in the refractoriness of BRAF V600E CRC, but the underlying molecular mechanism needs to be elucidated. Here, heat shock 70 kDa protein 8 (HSPA8), an essential regulator in chaperone-mediated autophagy (CMA), is identified as a potential therapeutic target for advanced BRAF V600E CRC. These results show that HSPA8 is transcriptionally upregulated in BRAF V600E CRC, which promotes CMA-dependent degradation of caveolin-1 (CAV1) to release β-catenin into the nucleus and thus activates the Wnt/β-catenin pathway, contributing to metastasis and progression of BRAF V600E CRC. Of note, HSPA8 directly interacts with the KIFSN motif on CAV1, the interaction can be enhanced by p38 MAPK-mediated CAV1 S168 phosphorylation. Furthermore, pharmacological targeting HSPA8 by VER155008 exhibits synergistic effects with BRAF inhibitors on CRC mouse models. In summary, these findings discover the important role of the HSPA8/CAV1/β-catenin axis in the development of refractory BRAF V600E CRC and highlight HSPA8 as a predictive biomarker and therapeutic target in clinical practice.

Different effects of crizotinib treatment in two non-small cell lung cancer patients with SDC4::ROS1 fusion variants

The possibility of stratifying patients according to differences in ROS proto-oncogene 1 (ROS1) fusion partners has been discussed. This study aimed to clarify the clinicopathological differences between two SDC4::ROS1 positive NSCLC cases who had different responses to crizotinib. Cytology and pathology samples from two NSCLC cases with SDC4::ROS1 who were diagnosed and treated with crizotinib at Nihon University Itabashi Hospital were obtained. Case 1 has been well-controlled with crizotinib for over 5 years, but case 2 was worse and overall survival was 19 months. Sequencing analysis of ROS1 fusion genes was performed by reverse-transcription-PCR and Sanger's sequencing methods. In addition, thyroid transcription factor (TTF)-1, ROS-1, Ki67, and phosphorylated extracellular signal-regulated kinase (pERK)1/2 expression were investigated using immunohistochemistry. Sequencing analysis showed SDC4 exon2::ROS1 exon 32 (exon33 deleted) in case 1, and coexistence of SDC4 exon2::ROS1 exon 34 and SDC4 exon2::ROS1 exon35 in case 2. The Ki67 index was not different, but ROS1 and pERK1/2 expression levels tended to be higher in the tumor cells of case 2 than in case 1. Therapeutic response to crizotinib and patients' prognosis in ROS1 rearranged NSCLC may be related to the activation of ROS1 signaling, depending on ROS1 and pERK1/2 overexpression status, even if the ROS1 fusion partner is the same.

The type II RAF inhibitor tovorafenib in relapsed/refractory pediatric low-grade glioma: the phase 2 FIREFLY-1 trial

BRAF genomic alterations are the most common oncogenic drivers in pediatric low-grade glioma (pLGG). Arm 1 (n = 77) of the ongoing phase 2 FIREFLY-1 (PNOC026) trial investigated the efficacy of the oral, selective, central nervous system-penetrant, type II RAF inhibitor tovorafenib (420 mg m-2 once weekly; 600 mg maximum) in patients with BRAF-altered, relapsed/refractory pLGG. Arm 2 (n = 60) is an extension cohort, which provided treatment access for patients with RAF-altered pLGG after arm 1 closure. Based on independent review, according to Response Assessment in Neuro-Oncology High-Grade Glioma (RANO-HGG) criteria, the overall response rate (ORR) of 67% met the arm 1 prespecified primary endpoint; median duration of response (DOR) was 16.6 months; and median time to response (TTR) was 3.0 months (secondary endpoints). Other select arm 1 secondary endpoints included ORR, DOR and TTR as assessed by Response Assessment in Pediatric Neuro-Oncology Low-Grade Glioma (RAPNO) criteria and safety (assessed in all treated patients and the primary endpoint for arm 2, n = 137). The ORR according to RAPNO criteria (including minor responses) was 51%; median DOR was 13.8 months; and median TTR was 5.3 months. The most common treatment-related adverse events (TRAEs) were hair color changes (76%), elevated creatine phosphokinase (56%) and anemia (49%). Grade ≥3 TRAEs occurred in 42% of patients. Nine (7%) patients had TRAEs leading to discontinuation of tovorafenib. These data indicate that tovorafenib could be an effective therapy for BRAF-altered, relapsed/refractory pLGG. ClinicalTrials.gov registration: NCT04775485 .

Role of c-Src in Carcinogenesis and Drug Resistance

The aberrant transformation of normal cells into cancer cells, known as carcinogenesis, is a complex process involving numerous genetic and molecular alterations in response to innate and environmental stimuli. The Src family kinases (SFK) are key components of signaling pathways implicated in carcinogenesis, with c-Src and its oncogenic counterpart v-Src often playing a significant role. The discovery of c-Src represents a compelling narrative highlighting groundbreaking discoveries and valuable insights into the molecular mechanisms underlying carcinogenesis. Upon oncogenic activation, c-Src activates multiple downstream signaling pathways, including the PI3K-AKT pathway, the Ras-MAPK pathway, the JAK-STAT3 pathway, and the FAK/Paxillin pathway, which are important for cell proliferation, survival, migration, invasion, metastasis, and drug resistance. In this review, we delve into the discovery of c-Src and v-Src, the structure of c-Src, and the molecular mechanisms that activate c-Src. We also focus on the various signaling pathways that c-Src employs to promote oncogenesis and resistance to chemotherapy drugs as well as molecularly targeted agents.

Targeting the RAS/RAF/MAPK pathway for cancer therapy: from mechanism to clinical studies

Metastatic dissemination of solid tumors, a leading cause of cancer-related mortality, underscores the urgent need for enhanced insights into the molecular and cellular mechanisms underlying metastasis, chemoresistance, and the mechanistic backgrounds of individuals whose cancers are prone to migration. The most prevalent signaling cascade governed by multi-kinase inhibitors is the mitogen-activated protein kinase (MAPK) pathway, encompassing the RAS-RAF-MAPK kinase (MEK)-extracellular signal-related kinase (ERK) pathway. RAF kinase is a primary mediator of the MAPK pathway, responsible for the sequential activation of downstream targets, such as MEK and the transcription factor ERK, which control numerous cellular and physiological processes, including organism development, cell cycle control, cell proliferation and differentiation, cell survival, and death. Defects in this signaling cascade are associated with diseases such as cancer. RAF inhibitors (RAFi) combined with MEK blockers represent an FDA-approved therapeutic strategy for numerous RAF-mutant cancers, including melanoma, non-small cell lung carcinoma, and thyroid cancer. However, the development of therapy resistance by cancer cells remains an important barrier. Autophagy, an intracellular lysosome-dependent catabolic recycling process, plays a critical role in the development of RAFi resistance in cancer. Thus, targeting RAF and autophagy could be novel treatment strategies for RAF-mutant cancers. In this review, we delve deeper into the mechanistic insights surrounding RAF kinase signaling in tumorigenesis and RAFi-resistance. Furthermore, we explore and discuss the ongoing development of next-generation RAF inhibitors with enhanced therapeutic profiles. Additionally, this review sheds light on the functional interplay between RAF-targeted therapies and autophagy in cancer.

Wild-type C-Raf gene dosage and dimerization drive prostate cancer metastasis

Mutated Ras and Raf kinases are well-known to promote cancer metastasis via flux through the Ras/Raf/MEK/ERK (mitogen-activated protein kinase [MAPK]) pathway. A role for non-mutated Raf in metastasis is also emerging, but the key mechanisms remain unclear. Elevated expression of any of the three wild-type Raf family members (C, A, or B) can drive metastasis. We utilized an in vivo model to show that wild-type C-Raf overexpression can promote metastasis of immortalized prostate cells in a gene dosage-dependent manner. Analysis of the transcriptomic and phosphoproteomic landscape indicated that C-Raf-driven metastasis is accompanied by upregulated MAPK signaling. Use of C-Raf mutants demonstrated that the dimerization domain, but not its kinase activity, is essential for metastasis. Endogenous Raf monomer knockouts revealed that C-Raf's ability to form dimers with endogenous Raf molecules is important for promoting metastasis. These data identify wild-type C-Raf heterodimer signaling as a potential target for treating metastatic disease.