Therapeutic strategies to target RAS-mutant cancers

An exosome-based nanoplatform for siRNA delivery combined with starvation therapy promotes tumor cell death through autophagy, overcoming refractory KRAS-mutated tumors and restoring cetuximab chemosensitivity

Multi-drug combination therapy is one of the most effective strategies for the treatment of drug-resistant and advanced tumors. Modern nanodrug delivery systems are crucial for multi-drug combination therapy and gene therapy. However, research on direct injection of RNAi has not yielded significant results. Artificial vectors are emerging as promising delivery systemts for RNA for gene therapy. In this study, a multi-drug therapy system was built based on a biodegradable exosome nano-platform exploiting the protective and low immunogenic properties of exosomes for RNA. This work aimed to accomplish the co-delivery of siRNA and 3-Bromopyruvic acid (3BP) on an exosome nanoplatform, enhancing targeting by coupling cetuximab (CTX) to exosome membranes, resulting in a new nanomedicine Exo@siRNA/3BP-CTX (ERBC) engineered exosomes. The synthesis conditions were optimized to obtain stable, safe, and effective nanomedicines. Successful targeting of tumors with CTX inhibited KRAS oncogene expression and significantly reduced glucose uptake by cancer cells. This enhanced the starvation therapy effect of the energy deprivation agent 3BP, thus promoting excessive autophagy activation in cells and doubling apoptosis. However, ERBC combined with CTX therapy restored cellular chemosensitivity to CTX. These findings indicate that engineered exosomes with dual therapeutic activities is a promising approach for treating refractory KRAS-mutant cancers.

Design and Evaluation of Bivalent K-Ras Inhibitors That Target the CAAX Binding Site and the Acidic Surface of Farnesyltransferase and Geranylgeranyltransferase I

Mutant K-Ras drives cancer through its membrane localization, which requires posttranslational modification by farnesyltransferase (FTase). FTase attaches farnesyl to the K-Ras C-terminal CVIM tetrapeptide, enabling membrane binding. However, K-Ras can also undergo compensatory geranylgeranylation by geranylgeranyltransferase I (GGTase I), making FTase inhibition alone ineffective. Dual inhibition of FTase and GGTase I is necessary to fully block K-Ras localization and its cancer activity. We developed bivalent inhibitors targeting both FTase and GGTase I by binding to the CVIM (C = cysteine, V = valine, I = isoleucine, M = methionine) site and an adjacent acidic surface. A nonthiol CVIM peptidomimetic based on a piperidine scaffold showed potent FTase inhibition (Ki = 2.1 nM) with less effect on GGTase I (Ki = 210 nM). Adding cationic modules to this compound produced dual inhibitors with enhanced potency (Ki = 2-5 nM), significantly improving upon previous agents. These bivalent inhibitors effectively reduced mutant K-Ras cancer cell viability and inhibited K-Ras farnesylation and geranylgeranylation in cells. This dual-targeting approach shows promise for treating K-Ras-driven cancers.

The emerging role of Sotorasib plus Panitumumab combination therapy in colorectal cancer treatment

Colorectal cancer (CRC) poses a substantial global health challenge, ranking as the third most commonly diagnosed and second most fatal cancer worldwide. With an increasing incidence, particularly in older populations, CRC demands innovative therapeutic approaches to address the limitations of existing treatments. One critical target in CRC is the KRAS gene, which is frequently mutated and implicated in various cancer-related processes. This narrative review explores the promising role of Sotorasib plus Panitumumab combination therapy in CRC treatment. Combining Sotorasib with Panitumumab, an EGFR antagonist, offers a synergistic approach to comprehensively block KRAS and EGFR pathways, potentially overcoming resistance mechanisms observed in monotherapies. The review discusses the evolution of CRC treatment from traditional chemotherapy to the advent of targeted therapies like Bevacizumab and Cetuximab. It highlights the limitations of existing therapies, including resistance and toxicities, emphasising the urgency for innovative approaches. The CodeBreak clinical trials, specifically CodeBreak 101 and CodeBreak 300, provide a focal point for evaluating the efficacy of Sotorasib plus Panitumumab in patients with refractory KRAS G12C-mutated mCRC. Preliminary results demonstrate significant improvements in progression-free survival (PFS) and objective response rates, suggesting a paradigm shift in CRC treatment. The preliminary findings from the CodeBreak 300 trial signify a transformative impact of Sotorasib plus Panitumumab in refractory KRAS G12C-mutated mCRC. With a notable increase in PFS and objective response rates and a well-tolerated safety profile, this combination therapy emerges as a potential new standard of care. The results present an optimistic outlook for patients resistant to conventional therapies.

Current status of KRAS G12C inhibitors in NSCLC and the potential for combination with anti-PD-(L)1 therapy: a systematic review

In recent years, precision medicine for non-small cell lung cancer (NSCLC) has made significant strides, particularly with advancements in diagnostic and therapeutic technologies. Targeted 7therapies and Anti-PD-(L)1 Therapies have emerged as vital treatment options, yet KRAS mutations, especially KRAS G12C, have been historically difficult to address. Due to the unique activation mechanism of KRAS G12C has led to the development of specific inhibitors, such as AMG 510 and MRTX849, which show promising therapeutic potential. However, results from the CodeBreaK 200 Phase III trial indicated that AMG 510 did not significantly improve overall survival compared to docetaxel. Resistance after prolonged use of KRAS G12C inhibitors continues to pose a challenge, prompting interest in new drugs and combination strategies. KRAS mutations can impair tumor-infiltrating T cell function and create an immunosuppressive tumor microenvironment, making the combination of KRAS G12C inhibitors with anti-PD-(L)1 therapies particularly appealing. Preliminary data suggest these combinations may enhance both survival and quality of life, though safety concerns remain a barrier. Ongoing research is crucial to refine treatment regimens and identify suitable patient populations. This review focuses on the development of KRAS G12C inhibitors in monotherapy and combination therapies for NSCLC, discussing major clinical trials and future research directions.

Rat Sarcoma (RAS)-Protein-Targeting Synthetic Cell-Penetrating Peptide as an Anticancer Biomaterial

Various bioactive materials, including peptides, have become potential candidates for slowing cancer growth and metastasis. Among bioactive peptides, a synthetic cell-penetrating peptide referred to as rat sarcoma (RAS)-binding peptide (RBP) was suggested as a potential entity that targets RAS with high affinity in MDA-MB-231 cancer cells. This RAS binding further inhibits the RAS-rapidly accelerated fibrosarcoma (RAF) protein-protein interaction. The current study revealed that RBP effectively suppresses proliferation and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation by disrupting the RAS-RAF interaction. This intervention not only inhibits cell migration and invasion but also has substantial potential for preventing metastasis. The RAS-RAF-ERK1/2 pathway is a key target for anticancer drug development because of frequent ERK and mitogen-activated protein kinase activation in human cancers. MDA-MB-231, a triple-negative breast cancer cell line, harbors a G13D Kirsten rat sarcoma viral oncogene homolog mutation, making it resistant to many drugs. In addition to its in vitro antitumor activity, RBP was identified as a potent antagonist that substantially arrests tumor growth and invasiveness in in vivo chicken egg and mouse xenograft tumor models. Notably, histopathological analyses revealed increased immune cell infiltration and decreased Ki-67 expression, confirming the ability of RBP to inhibit tumor cell proliferation. Taken together, these findings highlight RBP as a therapeutic anticancer biomaterial capable of impeding the progression and metastasis of RAS-mutated cancers.

All intrinsically active Erk1/2 mutants autophosphorylate threonine207/188, a plausible regulator of the TEY motif phosphorylation

The extracellular-activated kinases 1 & 2 (Erk1/2) are catalytically active when dually phosphorylated on a TEY motif located at the activation loop. In human patients with cardiac hypertrophy, Erk1/2 are phosphorylated on yet another activation loop's residue, T207/188. Intrinsically active variants of Erk1/2, mutated at R84/65, are also (auto)phosphorylated on T207/188. It is not known whether T207/188 phosphorylation is restricted to these cases, nor how it affects Erks' activity. We report that T207/188 phosphorylation is not rare, as we found that: 1) All known auto-activated Erk1/2 variants are phosphorylated on T207/188. 2) It occurs in various cell lines and mouse tissues. 3) It is extremely high in patients with skeletal muscle atrophies or myopathies. We propose that T207/188 controls the permissiveness of the TEY motif for phosphorylation because T207/188-mutated Erk1/2 and the yeast Erk/Mpk1 were efficiently dually phosphorylated when expressed in HEK293 or yeast cells, respectively. The T207/188-mutated Mpk1 was not TEY-phosphorylated in cells knocked out for MEKs, suggesting that its enhanced phosphorylation in wild-type cells is MEK-dependent. Thus, as T207/188-mutated Erk1/2 and Mpk1 recruit MEKs, the role of T207/188 is to impede MEKs' ability to phosphorylate Erks. T207/188 also impedes autophosphorylation as recombinant Erk2 mutated at T188 is spontaneously autophosphorylated, although exclusively on Y185. The role of T207/188 in regulating activation loop phosphorylation may be common to most Ser/Thr kinases, as 86% of them (in the human kinome) possess T207/188 orthologs, and 160 of them were already reported to be phosphorylated on this residue.

Molecular Dynamics Investigation into the Stability of KRas and CRaf Multimeric Complexes

In the Ras/Raf/MAPK signaling pathway, Ras and Raf proteins interact synergistically to form a tetrameric complex. NMR experiments have demonstrated that Ras dimerizes in solution and binds stably to Raf, forming Ras·Raf complexes. In this study, we constructed the ternary and quaternary complexes of KRas and CRaf based on crystal structures, denoted as (KRas)2·CRaf and (KRas)2·(CRaf)2, respectively. Molecular dynamics (MD) simulations were performed to investigate the stability of these complexes, while hydrogen bonds as well as salt bridges formed at the protein-protein interaction interfaces were analyzed based on simulation trajectories. The results revealed that the KRas·CRaf complex is more stable in explicit solvent compared with the KRas dimer. Formation of the stable quaternary complex (KRas)2·(CRaf)2 might be attributed to the association of two binary KRas·CRaf complexes. Additionally, MD simulations of the KRasG12D·CRaf complex revealed a stable and extended binding site at the KRas-CRaf interaction interface. This binding site was identified as a potential therapeutic target to block abnormal signal transmission in the pathway.

Phosphorylation of POU3F3 Mediated Nuclear Translocation Promotes Proliferation in Non-Small Cell Lung Cancer through Accelerating ATP5PF Transcription and ATP Production

Targeting oxidative phosphorylation (OXPHOS) through inhibiting the electron transport chain (ETC) has shown promising pre-clinical efficacy in cancer therapy. Although aerobic glycolysis is a hallmark of cancer, emerging evidence suggest OXPHOS is frequently enhanced, providing metabolic advantages for cell proliferation, metastasis, and drug resistance in a variety of aggressive cancer types including non-small cell lung cancer (NSCLC), yet the underlying molecular mechanisms remain elusive. Here it is reported that POU-domain containing family protein POU3F3 is translocated into the nuclei of NSCLC cell lines harboring mutant RAS, where it activates transcription of ATP5PF, an essential component of mitochondrial ATP synthase and consequent ATP production, leading to enhanced NSCLC proliferation and migration. Moreover, it is further found out that ERK1 phosphorylates POU3F3 at the S393 site in the cytoplasm and promotes the nuclear translocation of POU3F3 via receptor importin β1 in RAS mutant NSCLC cells. Mechanistically, RNA sequencing analysis combined with chromatin immunoprecipitation (ChIP) assay revealed that POU3F3 binds to the promoter of ATP5PF, leading to enhanced ATP5PF transcription and ATP production. Together, this study uncovers a novel RAS-POU3F3-ATP5PF axis in facilitating NSCLC progression, providing a new perspective on the understanding of molecular mechanisms for NSCLC progression.

Cholesterol metabolism in pancreatic cancer and associated therapeutic strategies

Pancreatic cancer remains one of the most lethal cancers due to late diagnosis and high chemoresistance. Despite recent progression in the development of chemotherapies, immunotherapies, and potential nanoparticles-based approaches, the success rate of therapeutic response is limited which is further compounded by cancer drug resistance. Understanding of emerging biological and molecular pathways causative of pancreatic cancer's aggressive and chemoresistance is vital to improve the effectiveness of existing therapeutics and to develop new therapies. One such under-investigated and relatively less explored area of research is documenting the effect that lipids, specifically cholesterol, and its metabolism, impose on pancreatic cancer. Dysregulated cholesterol metabolism has a profound role in supporting cellular proliferation, survival, and promoting chemoresistance and this has been well established in various other cancers. Thus, we aimed to provide an in-depth review focusing on the significance of cholesterol metabolism in pancreatic cancer and relevant genes at play, molecular processes contributing to cellular cholesterol homeostasis, and current research efforts to develop new cholesterol-targeting therapeutics. We highlight the caveats, weigh in different experimental therapeutic strategies, and provide possible suggestions for future research highlighting cholesterol's importance as a therapeutic target against pancreatic cancer resistance and cancer progression.

Ras S89D mutation induced allosteric changes that promoted its nucleotide exchange and signaling activation

The small GTPase Ras is among the most frequently mutated genes and its mutations often drive oncogenesis across various cancers. While the role of NRas phosphorylation at S89 in the context of a Q61R mutation in melanoma genesis remains controversial, the impact of S89 phosphorylation on NRas function has not been fully elucidated. In this study, we employed the S89D phosphorylation-mimetic mutation and demonstrated that the S89D mutation alone activated all Ras isoforms by increasing the GTP-bound population, thereby promoting ERK phosphorylation and cell proliferation. The S89D mutant retained unaltered hydrolysis kinetics and GTP/GDP relative affinity but exhibited an accelerated intrinsic nucleotide exchange rate, due to impaired nucleotide binding. A 1.2 Å crystal structure of the S89D mutant revealed substantial local conformational changes, as well as alterations propagating to the nucleotide-binding pocket, providing a structural basis for the observed biochemical properties. Collectively, these findings established that the S89D mutation activated Ras by enhancing intrinsic nucleotide exchange, offering new insights into Ras allostery.

Recent Anti-KRASG12D Therapies: A "Possible Impossibility" for Pancreatic Ductal Adenocarcinoma

Background: Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer, able to thrive in a challenging tumor microenvironment. Current standard therapies, including surgery, radiation, chemotherapy, and chemoradiation, have shown a dismal survival prognosis, resulting in less than a year of life in the metastatic setting. Methods: The pressing need to find better therapeutic methods brought about the discovery of new targeted therapies against the infamous KRAS mutations, the major oncological drivers of PDAC. Results: The most common KRAS mutation is KRASG12D, which causes a conformational change in the protein that constitutively activates downstream signaling pathways driving cancer hallmarks. Novel anti-KRASG12D therapies have been developed for solid-organ tumors, including small compounds, pan-RAS inhibitors, protease inhibitors, chimeric T cell receptors, and therapeutic vaccines. Conclusions: This comprehensive review summarizes current knowledge on the biology of KRAS-driven PDAC, the latest therapeutic options that have been experimentally validated, and developments in ongoing clinical trials.

The Role of KRAS Mutations in Colorectal Cancer: Biological Insights, Clinical Implications, and Future Therapeutic Perspectives

Background/Objectives: Colorectal cancer (CRC) remains a leading cause of cancer mortality globally, with KRAS mutations occurring in 30-40% of cases, contributing to poor prognosis and resistance to anti-EGFR therapy. This review explores the biological significance, clinical implications, and therapeutic targeting of KRAS mutations in CRC. Methods: A comprehensive analysis of the existing literature and clinical trials was performed, highlighting the role of KRAS mutations in CRC pathogenesis, their impact on prognosis, and recent advancements in targeted therapies. Specific attention was given to emerging therapeutic strategies and resistance mechanisms. Results: KRAS mutations drive tumor progression through persistent activation of MAPK/ERK and PI3K/AKT signaling pathways. These mutations influence the tumor microenvironment, cancer stem cell formation, macropinocytosis, and cell competition. KRAS-mutant CRC exhibits poor responsiveness to anti-EGFR monoclonal antibodies and demonstrates primary and acquired resistance to KRAS inhibitors. Recent breakthroughs include the development of KRAS G12C inhibitors (sotorasib and adagrasib) and promising agents targeting G12D mutations. However, response rates in CRC remain suboptimal compared to other cancers, necessitating combination therapies and novel approaches, such as vaccines, nucleic acid-based therapeutics, and macropinocytosis inhibitors. Conclusions: KRAS mutations are central to CRC pathogenesis and present a significant therapeutic challenge. Advances in KRAS-targeted therapies offer hope for improved outcomes, but resistance mechanisms and organ-specific differences limit efficacy. Continued efforts in personalized treatment strategies and translational research are critical for overcoming these challenges and improving patient survival.

Adaptive Plasticity Tumor Cells Modulate MAPK-Targeting Therapy Response in Colorectal Cancer

MAPK pathway inhibitors (MAPKi) are increasingly used in the treatment of advanced colorectal cancer, but often produce short-lived responses in patients. Although acquired resistance by de novo mutations in tumors have been found to reduce response in some patients, additional mechanisms underlying the limited response durability of MAPK targeting therapy remain unknown. Here, we denote new contributory tumor biology and provide insight on the impact of tumor plasticity on therapy response. Analysis of MAPKi treated patients revealed activation of stemness programs and increased ASCL2 expression, which are associated with poor outcomes. Greater ASCL2 with MAPKi treatment was also seen in patient-derived CRC models, independent of driver mutations. We find ASCL2 denotes a distinct cell population, arising from phenotypic plasticity, with a proliferative, stem-like phenotype, and decreased sensitivity to MAPKi therapy, which were named adaptive plasticity tumor (APT) cells. MAPK pathway suppression induces the APT phenotype in cells, resulting in APT cell enrichment in tumors and limiting therapy response in preclinical and clinical data. APT cell depletion improved MAPKi treatment efficacy and extended MAPKi response durability in mice. These findings uncover a cellular program that mitigates the impact of MAPKi therapies and highlights the importance of addressing tumor plasticity to improve clinical outcomes.

Ferroptosis and its relationship with cancer

Marked by iron buildup and lipid peroxidation, ferroptosis is a relatively new regulatory cell death (RCD) pathway. Many diseases like cancer, myocardial ischemia-reperfusion injury (MIRI), neurological disorders and acute renal failure (AKI) are corelated with ferroptosis. The main molecular processes of ferroptosis discovered yet will be presented here, along with the approaches in which it interacts with tumour-associated signaling pathways and its uses in systemic therapy, radiation therapy, and immunotherapy managing tumors.

Small-molecule inhibitors of WNT signalling in cancer therapy and their links to autophagy and apoptosis

Cancer represents an intricate and heterogeneous ailment that evolves from a multitude of epigenetic and genetic variations that disrupt normal cellular function. The WNT/β-catenin pathway is essential in maintaining the balance between cell renewal and differentiation in various tissues. Abnormal activation of this pathway can lead to uncontrolled cell growth and initiate cancer across a variety of tissues such as the colon, skin, liver, and ovary. It enhances characteristics that lead to cancer progression, including angiogenesis, invasion and metastasis. Processes like autophagy and apoptosis which regulate cell death and play a crucial role in maintaining cellular equilibrium are also intimately linked with WNT/ β-catenin pathway. Thus, targeting WNT pathway has become a key strategy in developing antitumor therapies. Employing small molecule inhibitors has emerged as a targeted therapy to improve the clinical outcome compared to conventional cancer treatments. Many strategies using small molecule inhibitors for modulating the WNT/β-catenin pathway, such as hindering WNT ligands' secretion or interaction, disrupting receptor complex, and blocking the nuclear translocation of β-catenin have been investigated. These interventions have shown promise in both preclinical and clinical settings. This review provides a comprehensive understanding of the role of WNT/β-catenin signalling pathway's role in cancer, emphasizing its regulation of autophagy and apoptosis. Our goal is to highlight the potential of specific small molecule inhibitors targeting this pathway, fostering the development of novel, tailored cancer treatments.

Synergistic two-step inhibition approach using a combination of trametinib and onvansertib in KRAS and TP53-mutated colorectal adenocarcinoma

Colorectal malignancies associated with KRAS and TP53 mutations led us to investigate the effects of combination therapy targeting KRAS, MEK1, or PLK1 in colorectal cancer. MEK1 is downstream of RAS in the MAPK pathway, whereas PLK1 is a mitotic kinase of the cell cycle activated by MAPK and regulated by p53. Bioinformatics analysis revealed that patients with colorectal cancer had a high expression of MAP2K1 and PLK1. Furthermore, PLK1 and MEK1 activity in human colorectal adenocarcinoma (COAD) tissues was found to be highly upregulated compared to healthy tissues. To determine the sensitivity of KRAS or/and TP53-mutated cancer to KRAS, MEK1, or PLK1-targeted therapy, the inhibitors salirasib, trametinib, volasertib, and onvansertib were used in COAD cells with different KRAS and TP53 status. The results showed that combinations with trametinib and PLK1 inhibitors were more potent than combinations with salirasib. A combination of MEK1 and PLK1 inhibitors exhibited significant therapeutic effects on KRAS or/and TP53-mutated COAD cells. Notably, the combination of trametinib and onvansertib effectively suppressed tumor growth in a xenograft mouse model of KRAS and TP53-mutated COAD. This treatment induced G1 and G2/M arrest, respectively, and showed the strongest synergistic effect in KRAS and TP53-mutated SW48 cells expressing mutant KRASG13D and transduced with TP53 shRNA, ultimately leading to apoptotic cell death. These effects are attributed to two-step inhibition mechanism that blocks the MAPK signaling pathway and disrupts mitosis in KRAS and TP53-mutated COAD cells.

Decoding KRAS mutation in non-small cell lung cancer patients receiving immunotherapy: A retrospective institutional comparison and literature review

INTRODUCTION

KRAS mutation the most common molecular alteration in advanced non-small cell lung cancer (NSCLC) and is associated with an unfavourable prognosis, largely due to the lack of targeted therapeutic options for the majority of the KRAS mutated isoforms. The landscape of NSCLC treatment has expanded with the introduction of immune checkpoint inhibitors (ICIs). Nonetheless, data regarding the efficacy of ICI in NSCLC patients harbouring KRAS mutations are conflicting. This study aimed to compare clinical outcomes of ICIs in advanced NSCLC with different isoforms of KRAS mutations.

METHODS

A retrospective study was conducted on 143 patients with advanced NSCLC harbouring different KRAS mutation and treated with immune checkpoint inhibitors (ICI) between December 2020 and July 2022 at "Fondazione IRCCS Istituto Nazionale dei Tumori" in Milan. Log-rank and Cox Hazard methods were used for survival analysis.

RESULTS

We evaluated 143 patients with advanced non-small cell lung cancer (NSCLC) harboring KRAS mutations. The most common mutation was G12C (41 %), followed by G12V (23.7 %) and G12D (11.8 %). The G12C mutation was notably associated with a higher incidence of bone metastases (42 %). Immunotherapy was administered as monotherapy in 54.5 % of cases, while 69 % received it as part of a first-line combination with chemotherapy. Co-mutations were detected in 52 % of patients, with Q61 (63 %) and G12C (58 %) being the most prevalent. Among these, 24 % had STK11 co-mutations, and 29 % had TP53 co-mutations. No significant differences in overall survival (OS) or progression-free survival (PFS) were observed across different KRAS subtypes. The longest OS was seen in patients with Q61 (46.5 months), 13X (31.8 months), and G12C (28.7 months). The highest overall response rate (ORR) of 73 % was observed in the G12D group, particularly with the combination of chemoimmunotherapy, where stable disease was the most common outcome at 40 %. The median duration of response (DOR) was 7.4 months across both treatments. The longest DOR was seen in the G12V group at 10.2 months, with no significant difference between treatments. In contrast, the shortest DOR was in the G12A group, with 1.54 months in those treated with combination therapy compared to 2.57 months with single-agent therapy. Regarding co-mutations, patients with STK11 co-mutations had a higher median OS than those without (39.7 vs. 26.1 months), but this was not statistically significant (p = 1). Similarly, TP53 co-mutations were associated with a lower median OS (19.1 vs. 26.1 months, p = 0.7), though this too was not statistically significant. Importantly, bone metastases emerged as a significant adverse prognostic factor, nearly doubling the risk of mortality (HR: 2.81, p < 0.001), regardless of KRAS subtype or co-mutation status.

CONCLUSION

KRAS mutation subtypes demonstrate varying clinical outcomes. Although no statistically significant differences were observed in overall survival (OS) or progression-free survival (PFS), bone metastases were identified as a significant adverse prognostic factor, nearly doubling the risk of mortality (HR: 2.72, p < 0.001) regardless of KRAS subtype or co-mutation status. These findings underscore the importance of personalized treatment approaches tailored to the genetic profiles of patients with advanced NSCLC.

Pharmacokinetics, bioavailability, and tissue distribution of MRTX1133 in rats using UHPLC-MS/MS

Introduction

MRTX1133 is a selective and reversible small molecule inhibitor of KRAS (G12D), which significantly delays the progression of solid tumors. However, no study on the absorption, distribution, and excretion of MRTX1133.

Methods

A fast ultra-high performance liquid chromatography-tandem quadrupole mass spectrometry method was developed for the determination of MRTX1133 in rat plasma, tissue homogenate, and urine. The method applied to the pharmacokinetics, bioavailability, tissue distribution, and excretion of MRTX1133 after oral administration (25 mg/kg) and intravenous administration (5 mg/kg).

Results

The calibration curve for MRTX1133 in plasma and other homogenates was linear, with r 2 > 0.99. The intra- and inter-day accuracies were ranged from 85% to 115% and precision were within ± 10%. The matrix effect and recovery were within ± 15 %. The Cmax of MRTX1133 was 129.90 ± 25.23 ng/mL at 45 min after oral administration. The plasma half-life (t1/2) of MRTX1133 was 1.12 ± 0.46 h after oral administration and 2.88 ± 1.08 after intravenous administration. Its bioavailability was 2.92%. Furthermore, MRTX1133 was widely distributed in all the main organs, including liver, kidney, lung, spleen, heart, pancreas, and intestine. MRTX1133 was still detectable in liver, kidney, lung, spleen, heart, and pancreas after 24 h. The excretion ratio of prototype MRTX1133 through kidney was 22.59% ± 3.22% after 24 h.

Conclusions

MRTX1133 was quickly absorbed, and widely distributed in the main organs. This study provided a reference for the quantitative determination of MTRX1133 in preclinical or clinical trials.

Adagrasib in the Treatment of KRAS p.G12C Positive Advanced NSCLC: Design, Development and Place in Therapy

One of the most common mutations seen in lung cancers are mutations in Kristen Rat Sarcoma Viral Oncogene Homolog (KRAS), observed in 25-30% of patients with NSCLC. Mutations in KRAS result in oncogenesis via persistent activation of the MAPK/ERK pathways. Although once thought to be "undruggable", KRAS p.G12C inhibitors such as sotorasib and adagrasib have been developed. This paper focuses on adagrasib, the second KRAS p.G12C inhibitor to obtain regulatory approval by the FDA and describes the details on its study design, development and current place in therapy.

Regorafenib Combined with BRAF/MEK Inhibitors for the Treatment of Refractory Melanoma Brain Metastases

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 NRASQ61-mutant; 19 with progressive MBM; 11 on corticosteroids). Thirteen BRAFV600-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 BRAFV600-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.

USP7 deubiquitinates KRAS and promotes non-small cell lung cancer

RAS oncogenic mutations are pivotal drivers of tumorigenesis. Ubiquitination modulates RAS functions, including activation, stability, and localization. While several E3 ligases regulate RAS ubiquitination, RAS deubiquitination remains less understood. Our study reveals that ubiquitin-specific protease 7 (USP7) directly deubiquitinates KRAS, stabilizing it and promoting the proliferation of non-small cell lung cancer (NSCLC) cells. Mechanistically, USP7 binds KRAS via its TRAF domain and removes the K48-linked polyubiquitin chains from residue K147. In addition, USP7 also stabilizes oncogenic KRAS mutants through deubiquitination. In lung cancer tissues, high USP7 expression is positively correlated with KRAS and is associated with lower patient survival rates. Moreover, USP7 inhibitors suppress NSCLC cell proliferation, particularly in cells resistant to the KRAS-G12C inhibitor AMG510. In conclusion, our findings identify USP7 as a key deubiquitinase regulating RAS stability, and targeting USP7 is a promising strategy to counteract KRAS inhibitor resistance in NSCLC.

Nutritional Glutamine-Modified Iron-Delivery System with Enhanced Endocytosis for Ferroptosis Therapy of Pancreatic Tumors

Heterogeneous reprogrammed nutrient metabolic networks formed by oncogenes exhibit the potential for exploring novel druggable targets and developing innovative anticancer therapeutics. Herein, based on the heterogeneous metabolic characteristics of glutamine (Gln) addiction in pancreatic cancer cells, an iron-delivery system (IDS) with enhanced endocytosis is designed for efficient ferroptosis therapy. The IDS is characterized by Gln modification and can be recognized as a source of Gln nutrients for efficient endocytic uptake by pancreatic tumor cells. Because the IDS is flexible to combine with amino acid-like components, the IDS with enhanced endocytosis is further produced by loading the Gln transporter inhibitor of V9302. V9302 is capable of suppressing molecular Gln uptake via transporter ASCT2, which generates Gln deprivation to direct metabolic reprogramming of cancer cells and enhances cellular uptake of Gln-modified IDS via RAS-stimulated macropinocytosis. The enhanced endocytosis and high iron content of IDS facilitate ferroptosis in mice pancreatic tumor models; thus, an amino acid-like ferroptosis inducer of l-buthionine sulfoximine (BSO) is further combined. The enhanced endocytosis resulting from the synergism of Gln and V9302 enables the efficient delivery of iron and BSO for ferroptosis tumor therapy. This work provides an alternative approach for enhancing intracellular drug delivery of the tumors with heterogeneous nutrient metabolism by virtue of combining nutrient-modified nanodrugs with the corresponding nutrient transporter inhibitors.

RAS signaling in carcinogenesis, cancer therapy and resistance mechanisms

Variants in the RAS family (HRAS, NRAS and KRAS) are among the most common mutations found in cancer. About 19% patients with cancer harbor RAS mutations, which are typically associated with poor clinical outcomes. Over the past four decades, KRAS has long been considered an undruggable target due to the absence of suitable small-molecule binding sites within its mutant isoforms. However, recent advancements in drug design have made RAS-targeting therapies viable, particularly with the approval of direct KRASG12C inhibitors, such as sotorasib and adagrasib, for treating non-small cell lung cancer (NSCLC) with KRASG12C mutations. Other KRAS-mutant inhibitors targeting KRASG12D are currently being developed for use in the clinic, particularly for treating highly refractory malignancies like pancreatic cancer. Herein, we provide an overview of RAS signaling, further detailing the roles of the RAS signaling pathway in carcinogenesis. This includes a summary of RAS mutations in human cancers and an emphasis on therapeutic approaches, as well as de novo, acquired, and adaptive resistance in various malignancies.

High Resolution Ion Mobility Enables the Structural Characterization of Atropisomers of GDC-6036, a KRAS G12C Covalent Inhibitor

GDC-6036 is a covalent KRAS G12C inhibitor that demonstrates high potency and selectivity. Structurally, GDC-6036 consists of several motifs that make the analytical characterization of this molecule challenging, including a highly basic pyrrolidine motif bonded to a quinazoline ring via an ether bond and an atropisomeric carbon-carbon bond between functionalized pyridine and quinazoline groups. Structurally, the desired atropisomer was synthesized via an atroposelective Negishi coupling with very high yield. However, having a direct way to analyze and confirm the presence of the atropisomeric species remained challenging in routine analytical workflows. In this study, both variable temperature nuclear magnetic resonance (VT-NMR) and two different approaches of in-line ion mobility coupled to liquid chromatography mass spectrometry (LC-MS) workflows were evaluated for the characterization of GDC-6036 and its undesired atropisomer (Compound B) to support synthetic route development. Briefly, both VT-NMR and traveling wave ion mobility spectrometry (TWIMS) enabled by structures for lossless ion manipulation (SLIM) technology coupled to high resolution MS (HRMS) are able to elucidate the structures of the atropisomers in a complex mixture. Drift tube IMS (DTIMS) was also evaluated, but lacked the resolving power to demonstrate separation between the two species in a mixture, but did show slight differences in their arrival times when multiplexed and injected separately. The determined resolving power (Rp) by multiplexing the ions via DTIMS was 67.3 and 60.5 for GDC-6036 and Compound B, respectively, while the two peak resolving power (Rpp) was determined to be 0.41, indicating inadequate resolution between the two species. Alternatively, the SLIM-IM studies showed Rp of 103.8 and 99.4, with a Rpp of 2.64, indicating good separation between the atropisomers. Furthermore, the CCS/z for GDC-6036 and Compound B was determined to be 231.2 Å2/z and 235.0 Å2/z, respectively. Quantitative experiments demonstrate linearity (R2 >0.99) for both GDC-6036 and Compound B while maintaining separation via SLIM-IM. Spike recoveries of one atropisomer relative to the other yielded strong recoveries (98.7% to 102.5%) while maintaining reproducibility (<7% RSD). The study herein describes the analytical process for evaluating new technologies and strategies for implementation in routine biopharmaceutical characterization workflows.

Tunneling nanotubes mediate KRas transport: Inducing tumor heterogeneity and altering cellular membrane mechanical properties

Mutation in oncogene KRas plays a crucial role in the occurrence and progression of numerous malignant tumors. Malignancy involves changes in cell mechanics for extensive cellular deformation during metastatic dissemination. We hypothesize that oncogene KRas mutations are intrinsic to alterations in cellular mechanics that promote malignant tumor generation and progression. Here, we demonstrate the use of optical tweezers coupled with a confocal fluorescence imaging system and gene interference technique to reveal that the mutant KRas protein can be transported between homogeneous and heterogeneous tumor cells by tunneling nanotubes (TNTs), resulting in a significant reduction of membrane tension and acceleration of membrane phospholipid flow in the recipient cells. Simultaneously, the changes in membrane mechanical properties of the tumor cells also enhance the metastatic and invasive ability of the tumors, which further contribute to the deterioration of the tumors. This finding helps to clarify the association between oncogene mutations and changes in the mechanical properties of tumor cells, which provides a theoretical basis for the development of cancer treatment strategies. STATEMENT OF SIGNIFICANCE: Here, we present a laser confocal fluorescence system integrated with optical tweezers to observe the transfer of mutant KRasG12D protein from mutant cells to wild-type cells through TNTs. Malignancy involves changes in cell mechanics for extensive cellular deformation during metastatic dissemination. Our results demonstrate a significant decrease in membrane tension and an increase in membrane phospholipid flow in recipient cells. These alterations in mechanical properties augment the migration and invasive capabilities of tumor cells, contributing to tumor malignancy. Our findings propose that cellular mechanical properties could serve as new markers for tumor development, and targeting membrane tension may hold potential as a therapeutic strategy.

The interlacing anticancer effect of pharmacologic ascorbate, chloroquine, and resveratrol

Currently, a diagnosis with KRAS mutant pancreatic ductal adenocarcinoma (PDAC) means a death warrant, so finding efficient therapeutic options is a pressing issue. Here, we presented that pharmacologic ascorbate, chloroquine and resveratrol co-treatment exerted a synergistic cytotoxic effect on PDAC cell lines. The observed synergistic cytotoxicity was a general feature in all investigated cancer cell lines independent of the KRAS mutational status and seems to be independent of the autophagy inhibitory effect of chloroquine. Furthermore, it seems that apoptosis and necroptosis are also not likely to play any role in the cytotoxicity of chloroquine. Both pharmacologic ascorbate and resveratrol caused double-strand DNA breaks accompanied by cell cycle arrest. It seems resveratrol-induced cytotoxicity is independent of reactive oxygen species (ROS) generation and accompanied by a significant elevation of caspase-3/7 activity, while pharmacologic ascorbate-induced cytotoxicity shows strong ROS dependence but proved to be caspase-independent. Our results are particularly important since ascorbate and resveratrol are natural compounds without significant harmful effects on normal cells, and chloroquine is a known antimalarial drug that can easily be repurposed.

Onychocolone A produced by the fungus Onychocola sp. targets cancer stem cells and stops pancreatic cancer progression by inhibiting MEK2-dependent cell signaling

Pancreatic cancer (PC) shows a high fatality rate that can only be faced with a combination of surgery and chemotherapy or palliative treatment in the case of advanced patients. Besides, PC tumors are enriched with subpopulations of cancer stem cells (CSCs) that are resistant to the existing chemotherapeutic agents, which raises an important need for the identification of new drugs. To fill this gap, we have tested the anti-tumoral activity of microbial extracts, which chemical diversity offers a broad spectrum of potential new bioactive compounds. Extracts derived from the fungus Onychocola sp. CF-107644 were assayed via high throughput screening followed by bioassay-guided fractionation and resulted in the identification and isolation of six benzophenone derivatives with antitumoral activity: onychocolones A-F (#1-6). The structures of the compounds were established by spectroscopic methods, including ESI-TOF MS, 1D and 2D NMR analyses and X-ray diffraction. Compounds #1-4 significantly inhibited the growth of the pancreas tumoral cell lines, with low-micromolar Median Effective Doses (ED50s). Compound #1 (onychocolone A) was prioritized for further profiling due to its pro-apoptotic effect, which was further validated on 3D spheroids and pancreatic CSCs. Protein expression assays showed that the effect was mechanistically linked to the inhibition of MEK onco-signaling pathway. The efficacy of onychocolone A was also demonstrated in vivo by the reduction of tumor growth in a pancreatic xenograft mouse model generated by CSCs. Altogether, the data support that onychocolone A is a promising new small molecule for hit-to-lead development of a new treatment for PC.

Targeting guanine nucleotide exchange factors for novel cancer drug discovery

INTRODUCTION

Guanine nucleotide exchange factors (GEFs) regulate the activation of small GTPases (G proteins) of the Ras superfamily proteins controlling cellular functions. Ras superfamily proteins act as 'molecular switches' that are turned 'ON' by guanine exchange. There are five major groups of Ras family GTPases: Ras, Ran, Rho, Rab and Arf, with a variety of different GEFs regulating their GTP loading. GEFs have been implicated in various diseases including cancer. This makes GEFs attractive targets to modulate signaling networks controlled by small GTPases.

AREAS COVERED

In this review, the roles and mechanisms of GEFs in malignancy are outlined. The mechanism of guanine exchange activity by GEFs on a small GTPase is illustrated. Then, some examples of GEFs that are significant in cancer are presented with a discussion on recent progress in therapeutic targeting efforts using a variety of approaches.

EXPERT OPINION

Recently, GEFs have emerged as potential therapeutic targets for novel cancer drug development. Targeting small GTPases is challenging; thus, targeting their activation by GEFs is a promising strategy. Most GEF-targeted drugs are still in preclinical development. A deeper biological understanding of the underlying mechanisms of GEF activity and utilizing advanced technology are necessary to enhance drug discovery for GEFs in cancer.

Breast cancer drug resistance: Decoding the roles of Hippo pathway crosstalk

The most significant factors that lead to cancer-related death in breast cancer (BC) patients include drug resistance, migration, invasion, and metastasis. Several signaling pathways are involved in the development of BC. The different types of BC are initially sensitive to chemotherapy, and drug resistance can occur through multiple molecular mechanisms. Regardless of developing targeted Therapy, due to the heterogenic nature and complexity of drug resistance, it is a major clinical challenge with the low survival rate in BC patients. The deregulation of several signaling pathways, particularly the Hippo pathway (HP), is one of the most recent findings about the molecular mechanisms of drug resistance in BC, which are summarized in this review. Given that HP is one of the recent cancer research hotspots, this review focuses on its implication in BC drug resistance. Unraveling the different molecular basis of HP through its crosstalk with other signaling pathways, and determining the effectiveness of HP inhibitors can provide new insights into possible therapeutic strategies for overcoming chemoresistance in BC.

Cancer research is not correlated with driver gene mutation burdens

BACKGROUND

Cancer research is pursued with the goal of positively impacting patients with cancer. Decisions regarding how to allocate research funds reflect a complex balancing of priorities and factors. Even though these are subjective decisions, they should be made with consideration of all available objective facts. An accurate estimate of the affected cancer patient population by mutation is one variable that has only recently become available to inform funding decisions.

METHODS

We compared the overall incident burden of mutations within each cancer-associated gene with two measures of cancer research efforts: research grant funding amounts and numbers of academic manuscripts. We ask to what degree the aggregate set of cancer research efforts reflects the relative burdens of the different cancer genetic drivers. We thoroughly investigate the design of our queries to ensure that the presented results are robust and conclusions are well justified.

FINDINGS

We find cancer research is generally not correlated with the relative burden of mutation within the different genetic drivers of cancer.

CONCLUSIONS

We suggest that cancer research would benefit from incorporating, among other factors, an epidemiologically informed mutation-estimate baseline into a larger framework for funding and research allocation decisions.

FUNDING

This work was supported in part by the National Institutes of Health (NIH) P30CA014195 and NIH DP2AT011327.

Ferroptosis in cancer (Review)

Ferroptosis is a type of programmed cell death depending on iron and reactive oxygen species. This unique cell death process has attracted a great deal of attention in the field of cancer research over the past decade. Research on the association of ferroptosis signal pathways and cancer development indicated that targeting ferroptosis has great potential for cancer therapy. In the present study, the latest research progress of ferroptosis was reviewed, focusing on the relationship between ferroptosis and the development of cancer, in order to further promote the clinical application of ferroptosis in cancer.

Grifolin Induces Cell Death of Human Lung Cancer A549 Cell Line via Inhibiting KRAS-Mediated Multiple Signaling Pathways

In the current work, grifolin was obtained from the twigs and leaves of Daphne genkwa for the first time and displayed significant growth inhibition against human lung carcinoma A549 cells. Subsequent in vitro antitumor evaluation revealed that grifolin could induce remarkable cell apoptosis and G0/G1 phase arrest, as well as block cell migration and invasion. In addition, grifolin also disrupted cellular energy metabolism by inducing reactive oxygen species, reducing adenosine triphosphate and mitochondrial membrane potential, and damaging DNA synthesis. Further RNA-seq analysis demonstrated that treatment of grifolin on A549 cells led to gene enrichment in MAPK, PI3K/Akt and NF-κB signaling pathways, all of which were inhibited by grifolin according to immunoblotting experiments. Further mechanistical studies disclosed that the expression of a key upstream protein KRAS was also blocked, and the cell death triggered by grifolin could be rescued by a RAS activator ML-099. Moreover, pretreatment of ML-099 on A549 cells could reverse the grifolin-induced downregulation of key proteins in the three aforementioned pathways. These findings indicate that grifolin could induce cell death in A549 cell line by inhibiting KRAS-mediated multiple signaling pathways.

Advancements in combining targeted therapy and immunotherapy for colorectal cancer

Colorectal cancer (CRC) is a prevalent gastrointestinal cancer posing significant clinical challenges. CRC management traditionally involves surgery, often coupled with chemotherapy. However, unresectable or metastatic CRC (mCRC) presents a complex challenge necessitating innovative treatment strategies. Targeted therapies have emerged as the cornerstone of treatment in such cases, with interventions tailored to specific molecular attributes. Concurrently, immunotherapies have revolutionized cancer treatment by harnessing the immune system to combat malignant cells. This review explores the evolving landscape of CRC treatment, focusing on the synergy between immunotherapies and targeted therapies, thereby offering new avenues for enhancing the effectiveness of therapy for CRC.

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.

Tumor biomarkers for diagnosis, prognosis and targeted therapy

Tumor biomarkers, the substances which are produced by tumors or the body's responses to tumors during tumorigenesis and progression, have been demonstrated to possess critical and encouraging value in screening and early diagnosis, prognosis prediction, recurrence detection, and therapeutic efficacy monitoring of cancers. Over the past decades, continuous progress has been made in exploring and discovering novel, sensitive, specific, and accurate tumor biomarkers, which has significantly promoted personalized medicine and improved the outcomes of cancer patients, especially advances in molecular biology technologies developed for the detection of tumor biomarkers. Herein, we summarize the discovery and development of tumor biomarkers, including the history of tumor biomarkers, the conventional and innovative technologies used for biomarker discovery and detection, the classification of tumor biomarkers based on tissue origins, and the application of tumor biomarkers in clinical cancer management. In particular, we highlight the recent advancements in biomarker-based anticancer-targeted therapies which are emerging as breakthroughs and promising cancer therapeutic strategies. We also discuss limitations and challenges that need to be addressed and provide insights and perspectives to turn challenges into opportunities in this field. Collectively, the discovery and application of multiple tumor biomarkers emphasized in this review may provide guidance on improved precision medicine, broaden horizons in future research directions, and expedite the clinical classification of cancer patients according to their molecular biomarkers rather than organs of origin.

To explore the mechanism of Yigong San anti-gastric cancer and immune regulation

BACKGROUND

Yigong San (YGS) is a representative prescription for the treatment of digestive disorders, which has been used in clinic for more than 1000 years. However, the mechanism of its anti-gastric cancer and regulate immunity are still remains unclear.

AIM

To explore the mechanism of YGS anti-gastric cancer and immune regulation.

METHODS

Firstly, collect the active ingredients and targets of YGS, and the differentially expressed genes of gastric cancer. Secondly, constructed a protein-protein interaction network between the targets of drugs and diseases, and screened hub genes. Then the clinical relevance, mutation and repair, tumor microenvironment and drug sensitivity of the hub gene were analyzed. Finally, molecular docking was used to verify the binding ability of YGS active ingredient and hub genes.

RESULTS

Firstly, obtained 55 common targets of gastric cancer and YGS. The Kyoto Encyclopedia of Genes and Genomes screened the microtubule-associated protein kinase signaling axis as the key pathway and IL6, EGFR, MMP2, MMP9 and TGFB1 as the hub genes. The 5 hub genes were involved in gastric carcinogenesis, staging, typing and prognosis, and their mutations promote gastric cancer progression. Finally, molecular docking results confirmed that the components of YGS can effectively bind to therapeutic targets.

CONCLUSION

YGS has the effect of anti-gastric cancer and immune regulation.

Transglutaminase 2 serves as a pathogenic hub gene of KRAS mutant colon cancer based on integrated analysis

BACKGROUND

Colon cancer is acknowledged as one of the most common malignancies worldwide, ranking third in United States regarding incidence and mortality. Notably, approximately 40% of colon cancer cases harbor oncogenic KRAS mutations, resulting in the continuous activation of epidermal growth factor receptor signaling.

AIM

To investigate the key pathogenic genes in KRAS mutant colon cancer holds considerable importance.

METHODS

Weighted gene co-expression network analysis, in combination with additional bioinformatics analysis, were conducted to screen the key factors driving the progression of KRAS mutant colon cancer. Meanwhile, various in vitro experiments were also conducted to explore the biological function of transglutaminase 2 (TGM2).

RESULTS

Integrated analysis demonstrated that TGM2 acted as an independent prognostic factor for progression-free survival. Immunohistochemical analysis on tissue microarrays revealed that TGM2 was associated with an elevated probability of perineural invasion in patients with KRAS mutant colon cancer. Additionally, biological roles of the key gene TGM2 was also assessed, suggesting that the downregulation of TGM2 attenuated the proliferation, invasion, and migration of the KRAS mutant colon cancer cell line.

CONCLUSION

This study underscores the potential significance of TGM2 in the progression of KRAS mutant colon cancer. This insight not only offers a theoretical foundation for therapeutic approaches but also highlights the need for additional clinical trials and fundamental research to support our preliminary findings.

Design, synthesis, and evaluation of novel quindoline derivatives with fork-shaped side chains as RNA G-quadruplex stabilizers for repressing oncogene NRAS translation

NRAS mutation is the second most common oncogenic factor in cutaneous melanoma. Inhibiting NRAS translation by stabilizing the G-quadruplex (G4) structure with small molecules seems to be a potential strategy for cancer therapy due to the NRAS protein's lack of a druggable pocket. To enhance the effects of previously reported G4 stabilizers quindoline derivatives, we designed and synthesized a novel series of quindoline derivatives with fork-shaped side chains by introducing (alkylamino)alkoxy side chains. Panels of experimental results showed that introducing a fork-shaped (alkylamino)alkoxy side chain could enhance the stabilizing abilities of the ligands against NRAS RNA G-quadruplexes and their anti-melanoma activities. One of them, 10b, exhibited good antitumor activity in the NRAS-mutant melanoma xenograft mouse model, showing the therapeutic potential of this kind of compounds.

Tumour-selective activity of RAS-GTP inhibition in pancreatic cancer

Broad-spectrum RAS inhibition has the potential to benefit roughly a quarter of human patients with cancer whose tumours are driven by RAS mutations1,2. RMC-7977 is a highly selective inhibitor of the active GTP-bound forms of KRAS, HRAS and NRAS, with affinity for both mutant and wild-type variants3. More than 90% of cases of human pancreatic ductal adenocarcinoma (PDAC) are driven by activating mutations in KRAS4. Here we assessed the therapeutic potential of RMC-7977 in a comprehensive range of PDAC models. We observed broad and pronounced anti-tumour activity across models following direct RAS inhibition at exposures that were well-tolerated in vivo. Pharmacological analyses revealed divergent responses to RMC-7977 in tumour versus normal tissues. Treated tumours exhibited waves of apoptosis along with sustained proliferative arrest, whereas normal tissues underwent only transient decreases in proliferation, with no evidence of apoptosis. In the autochthonous KPC mouse model, RMC-7977 treatment resulted in a profound extension of survival followed by on-treatment relapse. Analysis of relapsed tumours identified Myc copy number gain as a prevalent candidate resistance mechanism, which could be overcome by combinatorial TEAD inhibition in vitro. Together, these data establish a strong preclinical rationale for the use of broad-spectrum RAS-GTP inhibition in the setting of PDAC and identify a promising candidate combination therapeutic regimen to overcome monotherapy resistance.

Combinatorial strategies to target RAS-driven cancers

Although RAS was formerly considered undruggable, various agents that inhibit RAS or specific RAS oncoproteins have now been developed. Indeed, the importance of directly targeting RAS has recently been illustrated by the clinical success of mutant-selective KRAS inhibitors. Nevertheless, responses to these agents are typically incomplete and restricted to a subset of patients, highlighting the need to develop more effective treatments, which will likely require a combinatorial approach. Vertical strategies that target multiple nodes within the RAS pathway to achieve deeper suppression are being investigated and have precedence in other contexts. However, alternative strategies that co-target RAS and other therapeutic vulnerabilities have been identified, which may mitigate the requirement for profound pathway suppression. Regardless, the efficacy of any given approach will likely be dictated by genetic, epigenetic and tumour-specific variables. Here we discuss various combinatorial strategies to treat KRAS-driven cancers, highlighting mechanistic concepts that may extend to tumours harbouring other RAS mutations. Although many promising combinations have been identified, clinical responses will ultimately depend on whether a therapeutic window can be achieved and our ability to prospectively select responsive patients. Therefore, we must continue to develop and understand biologically diverse strategies to maximize our likelihood of success.

Phase I/II Study of Combined BCL-xL and MEK Inhibition with Navitoclax and Trametinib in KRAS or NRAS Mutant Advanced Solid Tumors

PURPOSE

MEK inhibitors (MEKi) lack monotherapy efficacy in most RAS-mutant cancers. BCL-xL is an anti-apoptotic protein identified by a synthetic lethal shRNA screen as a key suppressor of apoptotic response to MEKi.

PATIENTS AND METHODS

We conducted a dose escalation study (NCT02079740) of the BCL-xL inhibitor navitoclax and MEKi trametinib in patients with RAS-mutant tumors with expansion cohorts for: pancreatic, gynecologic (GYN), non-small cell lung cancer (NSCLC), and other cancers harboring KRAS/NRAS mutations. Paired pretreatment and day 15 tumor biopsies and serial cell-free (cf)DNA were analyzed.

RESULTS

A total of 91 patients initiated treatment, with 38 in dose escalation. Fifty-eight percent had ≥3 prior therapies. A total of 15 patients (17%) had colorectal cancer, 19 (11%) pancreatic, 15 (17%) NSCLC, and 32 (35%) GYN cancers. The recommended phase II dose (RP2D) was established as trametinib 2 mg daily days 1 to 14 and navitoclax 250 mg daily days 1 to 28 of each cycle. Most common adverse events included diarrhea, thrombocytopenia, increased AST/ALT, and acneiform rash. At RP2D, 8 of 49 (16%) evaluable patients achieved partial response (PR). Disease-specific differences in efficacy were noted. In patients with GYN at the RP2D, 7 of 21 (33%) achieved a PR and median duration of response 8.2 months. No PRs occurred in patients with colorectal cancer, NSCLC, or pancreatic cancer. MAPK pathway inhibition was observed in on-treatment tumor biopsies. Reductions in KRAS/NRAS mutation levels in cfDNA correlated with clinical benefit.

CONCLUSIONS

Navitoclax in combination with trametinib was tolerable. Durable clinical responses were observed in patients with RAS-mutant GYN cancers, warranting further evaluation in this population.

Sotorasib Is a Pan-RASG12C Inhibitor Capable of Driving Clinical Response in NRASG12C Cancers

KRASG12C inhibitors, like sotorasib and adagrasib, potently and selectively inhibit KRASG12C through a covalent interaction with the mutant cysteine, driving clinical efficacy in KRASG12C tumors. Because amino acid sequences of the three main RAS isoforms-KRAS, NRAS, and HRAS-are highly similar, we hypothesized that some KRASG12C inhibitors might also target NRASG12C and/or HRASG12C, which are less common but critical oncogenic driver mutations in some tumors. Although some inhibitors, like adagrasib, were highly selective for KRASG12C, others also potently inhibited NRASG12C and/or HRASG12C. Notably, sotorasib was five-fold more potent against NRASG12C compared with KRASG12C or HRASG12C. Structural and reciprocal mutagenesis studies suggested that differences in isoform-specific binding are mediated by a single amino acid: Histidine-95 in KRAS (Leucine-95 in NRAS). A patient with NRASG12C colorectal cancer treated with sotorasib and the anti-EGFR antibody panitumumab achieved a marked tumor response, demonstrating that sotorasib can be clinically effective in NRASG12C-mutated tumors.

SIGNIFICANCE

These studies demonstrate that certain KRASG12C inhibitors effectively target all RASG12C mutations and that sotorasib specifically is a potent NRASG12C inhibitor capable of driving clinical responses. These findings have important implications for the treatment of patients with NRASG12C or HRASG12C cancers and could guide design of NRAS or HRAS inhibitors. See related commentary by Seale and Misale, p. 698. This article is featured in Selected Articles from This Issue, p. 695.

CDK4/6 inhibition sensitizes MEK inhibition by inhibiting cell cycle and proliferation in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is not sensitive to most chemotherapy drugs, leading to poor chemotherapy efficacy. Recently, Trametinib and Palbociclib have promising prospects in the treatment of pancreatic cancer. This article aims to explore the effects of Trametinib on pancreatic cancer and address the underlying mechanism of resistance as well as its reversal strategies. The GDSC (Genomics of Drug Sensitivity in Cancer) and CTD2 (Cancer Target Discovery and Development) were utilized to screen the potential drug candidate in PDAC cell lines. The dose-increase method combined with the high-dose shock method was applied to induce the Trametinib-resistant PANC-1 and MIA PaCa-2 cell lines. The CCK8 proliferation assay, colony formation assay, flow cytometry, and western blot were conducted to verify the inhibitory effect of Trametinib and Palbociclib. RNA-seq was performed in resistant PDAC cell lines to find the differential expression genes related to drug resistance and predict pathways leading to the reversal of Trametinib resistance. The GDSC and CTD2 database screening revealed that Trametinib demonstrates a significant inhibitory effect on PDAC. We found that Trametinib has a lower IC50 than Gemcitabine in PDAC cell lines. Both Trametinib and Gemcitabine can decrease the proliferation capacity of pancreatic cells, induce cell cycle arrest, and increase apoptosis. Simultaneously, the phosphorylation of the AKT and ERK pathways were inhibited by the treatment of Trametinib. In addition, the RNA-seq of Trametinib-induced resistance PDAC cell lines reveals that the cyclin-dependent kinase (CDK)-RB-E2F regulatory axis and G2/M DNA damage checkpoint might lead the drug resistance. Besides, the combination of Trametinib with Palbociclib could inhibit the proliferation and cell cycle of both resistant cells lines and also restore the sensitivity of drug-resistant cells to Trametinib. Last but not least, the interferon-α and interferon-γ expression were upregulated in resistance cell lines, which might lead to the reversal of drug resistance. The study shows Trametinib has a critical inhibitory effect on PDAC. Besides, the combination of Trametinib with Palbociclib can inhibit the proliferation of PDAC-resistant cells.

Targeting KRAS in cancer

RAS family variants-most of which involve KRAS-are the most commonly occurring hotspot mutations in human cancers and are associated with a poor prognosis. For almost four decades, KRAS has been considered undruggable, in part due to its structure, which lacks small-molecule binding sites. But recent developments in bioengineering, organic chemistry and related fields have provided the infrastructure to make direct KRAS targeting possible. The first successes occurred with allele-specific targeting of KRAS p.Gly12Cys (G12C) in non-small cell lung cancer, resulting in regulatory approval of two agents-sotorasib and adagrasib. Inhibitors targeting other variants beyond G12C have shown preliminary antitumor activity in highly refractory malignancies such as pancreatic cancer. Herein, we outline RAS pathobiology with a focus on KRAS, illustrate therapeutic approaches across a variety of malignancies, including emphasis on the 'on' and 'off' switch allele-specific and 'pan' RAS inhibitors, and review immunotherapeutic and other key combination RAS targeting strategies. We summarize mechanistic understanding of de novo and acquired resistance, review combination approaches, emerging technologies and drug development paradigms and outline a blueprint for the future of KRAS therapeutics with anticipated profound clinical impact.

Prognostic value of specific KRAS mutations in patients with colorectal peritoneal metastases

BACKGROUND

There is little evidence on KRAS mutational profiles in colorectal cancer (CRC) peritoneal metastases (PM). This study aims to determine the prevalence of specific KRAS mutations and their prognostic value in a homogeneous cohort of patients with isolated CRC PM treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

MATERIALS AND METHODS

Data were collected from 13 Italian centers, gathered in a collaborative group of the Italian Society of Surgical Oncology. KRAS mutation subtypes have been correlated with clinical and pathological characteristics and survival [overall survival (OS), local (peritoneal) disease-free survival (LDFS) and disease-free survival (DFS)].

RESULTS

KRAS mutations occurred in 172 patients (47.5%) out of the 362 analyzed. Two different prognostic groups of KRAS mutation subtypes were identified: KRASMUT1 (G12R, G13A, G13C, G13V, Q61H, K117N, A146V), median OS > 120 months and KRASMUT2 (G12A, G12C, G12D, G12S, G12V, G13D, A59E, A59V, A146T), OS: 31.2 months. KRASMUT2 mutations mainly occurred in the P-loop region (P < 0.001) with decreased guanosine triphosphate (GTP) hydrolysis activity (P < 0.001) and were more frequently related to size (P < 0.001) and polarity change (P < 0.001) of the substituted amino acid (AA). When KRASMUT1 and KRASMUT2 were combined with other known prognostic factors (peritoneal cancer index, completeness of cytoreduction score, grading, signet ring cell, N status) in multivariate analysis, KRASMUT1 showed a similar survival rate to KRASWT patients, whereas KRASMUT2 was independently associated with poorer prognosis (hazard ratios: OS 2.1, P < 0.001; DFS 1.9, P < 0.001; LDFS 2.5, P < 0.0001).

CONCLUSIONS

In patients with CRC PM, different KRAS mutation subgroups can be determined according to specific codon substitution, with some mutations (KRASMUT1) that could have a similar prognosis to wild-type patients. These findings should be further investigated in larger series.

Harnessing ferroptosis for enhanced sarcoma treatment: mechanisms, progress and prospects

Sarcoma is a malignant tumor that originates from mesenchymal tissue. The common treatment for sarcoma is surgery supplemented with radiotherapy and chemotherapy. However, patients have a 5-year survival rate of only approximately 60%, and sarcoma cells are highly resistant to chemotherapy. Ferroptosis is an iron-dependent nonapoptotic type of regulated programmed cell death that is closely related to the pathophysiological processes underlying tumorigenesis, neurological diseases and other conditions. Moreover, ferroptosis is mediated via multiple regulatory pathways that may be targets for disease therapy. Recent studies have shown that the induction of ferroptosis is an effective way to kill sarcoma cells and reduce their resistance to chemotherapeutic drugs. Moreover, ferroptosis-related genes are related to the immune system, and their expression can be used to predict sarcoma prognosis. In this review, we describe the molecular mechanism underlying ferroptosis in detail, systematically summarize recent research progress with respect to ferroptosis application as a sarcoma treatment in various contexts, and point out gaps in the theoretical research on ferroptosis, challenges to its clinical application, potential resolutions of these challenges to promote ferroptosis as an efficient, reliable and novel method of clinical sarcoma treatment.

Adeno-to-squamous transition drives resistance to KRAS inhibition in LKB1 mutant lung cancer

KRASG12C inhibitors (adagrasib and sotorasib) have shown clinical promise in targeting KRASG12C-mutated lung cancers; however, most patients eventually develop resistance. In lung patients with adenocarcinoma with KRASG12C and STK11/LKB1 co-mutations, we find an enrichment of the squamous cell carcinoma gene signature in pre-treatment biopsies correlates with a poor response to adagrasib. Studies of Lkb1-deficient KRASG12C and KrasG12D lung cancer mouse models and organoids treated with KRAS inhibitors reveal tumors invoke a lineage plasticity program, adeno-to-squamous transition (AST), that enables resistance to KRAS inhibition. Transcriptomic and epigenomic analyses reveal ΔNp63 drives AST and modulates response to KRAS inhibition. We identify an intermediate high-plastic cell state marked by expression of an AST plasticity signature and Krt6a. Notably, expression of the AST plasticity signature and KRT6A at baseline correlates with poor adagrasib responses. These data indicate the role of AST in KRAS inhibitor resistance and provide predictive biomarkers for KRAS-targeted therapies in lung cancer.

Multiple medicinal chemistry strategies of targeting KRAS: State-of-the art and future directions

KRAS is the most frequently mutated oncogene and drives the development and progression of malignancies, most notably non-small cell lung cancer (NSCLS), pancreatic ductal adenocarcinoma (PDAC) and colorectal cancer (CRC). However, KRAS proteins have maintained the reputation of being "undruggable" due to the lack of suitable deep pockets on its surface. One major milestone for KRAS inhibition was the discovery of the covalent inhibitors bond to the allosteric switch-II pocket of the KRASG12C protein. To date, the FDA has approved two KRASG12C inhibitors, sotorasib and adagrasib, for the treatment of patients with KRASG12C-driven cancers. Researchers have paid close attention to the development of inhibitors for other KRAS mutations and upstream regulatory factors. The KRAS targeted drug discovery has entered a state of rapid development. This article has aimed to present the current state of the art of drug development in the KRAS field. We systematically summarize recent advances in the discovery and optimization processes of direct KRAS inhibitors (including KRASG12C, KRASG12D, KRASG12A and KRASG12R inhibitors), indirect KRAS inhibitors (SOS1 and SHP2 inhibitors), pan-KRAS inhibitors, as well as proteolysis-targetingchimeras degrades and molecular chaperone modulators from the perspective of medicinal chemistry. We also discuss the current challenges and opportunities of KRAS inhibition and hope to shed light on future KRAS drug discovery.

Progress in RAS-targeted therapeutic strategies: From small molecule inhibitors to proteolysis targeting chimeras

As a widely considerable target in chemical biology and pharmacological research, rat sarcoma (RAS) gene mutations play a critical driving factor in several fatal cancers. Despite the great progress of RAS subtype-specific inhibitors, rapid acquired drug resistance could limit their further clinical applications. Proteolysis targeting chimera (PROTAC) has emerged as a powerful tool to handle "undruggable" targets and exhibited significant therapeutic benefit for the combat of drug resistance. Owing to unique molecular mechanism and binding kinetics, PROTAC is expected to become a feasible strategy to break the bottleneck of classical RAS inhibitors. This review aims to discuss the current advances of RAS inhibitors and especially focus on PROTAC strategy targeting RAS mutations and their downstream effectors for relevant cancer treatment.

Computational insights into KRAS G12C inhibition: exploring possible repurposing of Azacitidine and Ribavirin

Kirsten rat sarcoma (KRAS) stands out as the most prevalent mutated oncogene, playing a crucial role in the initiation and progression of various cancer types, including colorectal, lung and pancreatic cancer. The oncogenic modifications of KRAS are intricately linked to tumor development and are identified in 22% of cancer patients. This has spurred the necessity to explore inhibition mechanisms, with the aim of investigating and repurposing existing drugs for diagnosing cancers dependent on KRAS G12C In this investigation, 26 nucleoside-based drugs were collected from literature to assess their effectiveness against KRAS G12C. The study incorporates in-silico molecular simulations and molecular docking examinations of these nucleoside-derived drugs with the KRAS G12C protein using Protein Data Bank (PDB) ID: 5V71. The docking outcomes indicated that two drugs, Azacitidine and Ribavirin, exhibited substantial binding affinities of -8.7 and -8.3 kcal/mol, respectively. These drugs demonstrated stability in binding to the active site of the protein during simulation studies. Root mean square deviation (RMSD) analyses indicated that the complexes closely adhered to an equilibrium RMSD value ranging from 0.17 to 0.2 nm. Additionally, % occupancies, bond angles and the length of hydrogen bonds were calculated. These findings suggest that Azacitidine and Ribavirin may potentially serve as candidates for repurposing in individuals with KRAS-dependent cancers.