Expanding the Reach of Precision Oncology by Drugging All KRAS Mutants

First-line treatments for KRAS-mutant non-small cell lung cancer: current state and future perspectives

KRAS mutations are common in non-small cell lung cancer (NSCLC) and are associated with patient prognosis; however, targeting KRAS has faced various difficulties. Currently, immunotherapy, chemotherapy, and chemoimmunotherapy play pivotal roles in the first-line treatment of KRAS-mutated NSCLC. Here, we summarize the current evidence on first-line therapies and compare the treatment outcomes and biomarkers for different regimens. KRAS inhibitors and other emerging alternative treatments are also discussed, as combining these drugs with immunotherapy may serve as a promising first-line treatment for KRAS-mutated NSCLC in the future. We hope that this review will assist in first-line treatment choices and shed light on the development of novel agents for KRAS-mutated NSCLC.

Differences between lung adenocarcinoma and lung squamous cell carcinoma: Driver genes, therapeutic targets, and clinical efficacy

With the rapid advancements in second-generation gene sequencing technologies, a growing number of driver genes and associated therapeutic targets have been unveiled for lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC). While they are clinically classified as non-small cell lung cancer (NSCLC), they display distinct genomic features and substantial variations in clinical efficacy, underscoring the need for particular attention. Hence, this review provides a comprehensive overview of the latest advancements in driver genes, epigenetic targets, chemotherapy, targeted therapy, and immunotherapy for LUAD and LUSC. Additionally, it delves into the distinctions in signaling pathways and pivotal facets of clinical management specific to these two categories of lung cancer. Moreover, we furnish pertinent details regarding clinical trials pertaining to driver genes and epigenetics, thus establishing a theoretical foundation for the realization of precision treatments for LUAD and LUSC.

Copper-KRAS-COX2 Axis: A Therapeutic Vulnerability in Pancreatic Cancer

KRAS mutations are a hallmark of pancreatic ductal adenocarcinoma (PDAC), occurring in over 90% of tumors. Tumors with these mutations are highly dependent on copper, making the targeting of copper homeostasis an attractive strategy for treating PDAC due to the higher copper requirement of cancer cells compared to normal cells. Herein, we present the discovery, lead optimization, and structure-activity relationship study of a series of novel quinolyl pyrazinamides for the treatment PDAC. These compounds induce cell death through copper-mediated apoptosis and necroptosis. Our optimized compounds, 39 and 52, are potent, water-soluble and metabolically stable. Compound 52 exhibits 55% oral bioavailability and demonstrates significant in vivo efficacy without obvious toxicity in syngeneic models of PDAC. Additionally, compound 52 showed significant synergy with celecoxib, a selective COX2 inhibitor, both in vitro and in vivo. Our data suggest that compound 52 is a promising candidate for further development in KRAS-mutated cancers.

Discovery of Novel SHP2 ATTEC Degraders against Pancreatic Ductal Adenocarcinoma Harboring KRAS(G12D) Mutations

Aberrant expression of the phosphatase SHP2 is implicated in numerous cancers, including KRAS G12D mutation driven PDAC. Although several SHP2 inhibitors have been reported, specific inhibitors with potent efficacy are not yet available. Given the elevated autophagy in PDAC, herein, we first designed novel SHP2 degraders through autophagosome-tethering compound strategy. Among them, the preferred 11n formed hydrogen bonds with Arg 111 and Glu 250 residues of SHP2 to enhance interactions between SHP2 and LC3. 11n also possessed great efficacy and selectivity against KRAS G12D mutant cancer cells versus the wild type. Moreover, the degradation caused by 11n manipulated the signaling pathways associated with cell apoptosis, metastasis, and invasion to inhibit the tumor growth both in vitro and in vivo. These findings not only generated a useful tool for exploring the potential of targeting SHP2 degradation but also offered promising candidates to develop novel drugs based on the autophagy mechanism.

Discovery of Carbodiimide Warheads to Selectively and Covalently Target Aspartic Acid in KRASG12D

Targeted covalent inhibitors are known to be successful therapeutics used in various indications. Covalent drugs typically target cysteine, as cysteine is well suited due to its high nucleophilicity. However, its low abundance in protein binding sites represents a major limitation. As a result, there is a need to covalently target additional nucleophilic amino acids. Recent literature has reported covalent inhibitors labeling aspartic acid in KRASG12D. However, these compounds also covalently bind to KRASG12C, indicating their cross-reactivity to cysteine along with aspartic acid. We report here carbodiimides as a novel reactive group to selectively target aspartic acid. Covalent inhibitors bearing a carbodiimide moiety are shown to covalently label KRASG12D in biochemical and cellular assays. A high-resolution X-ray crystal structure was obtained, which illustrates the mechanism of the covalent bond formation with KRASG12D. Carbodiimide warheads show selectivity toward KRASG12D over other KRAS alleles and represent a new covalent warhead suitable for covalently binding to aspartic acid in a biochemical and cellular context.

Differential Response and Resistance to KRAS-Targeted Therapy

KRAS is the most frequently mutated oncogene. In epithelial malignancies such as lung, colorectal, and pancreatic tumors, KRAS is mutated in 25 to above 90% cases. KRAS was considered undruggable for over three decades until the recent development of covalent inhibitors targeting the KRAS G12C mutant. The recent approval of the KRAS G12C inhibitors sotorasib and adagrasib has ushered in a new era of KRAS-targeted therapy. Despite this success, a major challenge in KRAS-targeted therapy is intrinsic and acquired resistance to KRAS inhibitors. Clinical studies have shown that many patients with KRAS G12C cancers did not respond to sotorasib and adagrasib. Colorectal cancer, in particular, has a markedly lower response rate to KRAS G12C inhibitors compared to non-small cell lung cancer. Furthermore, the therapeutic response to KRAS G12C inhibition was short-lived, with quick emergence of acquired resistance. In this review, we summarize several major themes that have emerged from recent clinical and preclinical studies on the mechanisms of intrinsic and acquired resistance to KRAS-targeted therapy in colorectal, lung, and pancreatic cancers. We also discuss various combination strategies for targeting these mechanisms to overcome resistance to KRAS inhibitors.

Josephin Domain Containing 2 (JOSD2) inhibition as Pan-KRAS-mutation-targeting strategy for colorectal cancer

KRAS is the most common mutated oncogenes in colorectal cancer (CRC), yet effective therapeutic strategies for targeting multiple KRAS mutations remained challenging. The prolonged protein stability of KRAS mutants contribute to their robust tumor-promoting effects, but the underlying mechanism is elusive. Herein by screening deubiquitinases (DUBs) siRNA library, we identify Josephin domain containing 2 (JOSD2) functions as a potent DUB that regulates the protein stability of KRAS mutants. Mechanistically, JOSD2 directly interacts with and stabilizes KRAS variants across different mutants, by reverting their proteolytic ubiquitination; while KRAS mutants reciprocally inhibit the catalytic activity of CHIP, a bona fide E3 ubiquitin ligase for JOSD2, thus forming a JOSD2/KRAS positive feedback circuit that significantly accelerates KRAS-mutant CRC growth. Inhibition of JOSD2 by RNA interference or its pharmacological inhibitor promotes the polyubiquitination and proteasomal degradation of KRAS mutants, and preferentially impede the growth of KRAS-mutant CRC including patient-derived cells/xenografts/organoids (PDCs/PDXs/PDOs) over that harboring wild-type KRAS. Collectively, this study not only reveals the crucial roles of JOSD2/KRAS positive feedback circuit in KRAS-mutant CRC, but also provides a rationale to target JOSD2 as the promising pan-KRAS-mutation-targeting strategy for the treatment of a broad population of CRC patients with KRAS variant across different mutant types.

Targeting KRAS-G12C in lung cancer: The emerging role of PROTACs in overcoming resistance

In lung cancer, KRAS mutations, especially the G12C, favor aggressive tumor growth and resistance to standard therapies. Although first-generation inhibitors of KRAS G12C, such as sotorasib and adagrasib, are highly effective in early-phase studies, resistance invariably develops under selective inhibition pressure and rarely leads to sustained long-term treatment benefits. As a novel approach to targeting KRAS mutations in lung cancer, PROTAC (Proteolysis Targeting Chimera) technology is explored in this review. The PROTACs take advantage of the cell's ubiquitin-proteasome system to selectively degrade KRAS proteins, overcoming the dilemma of a lack of traditional binding sites and the means of resistance. We review recent progress with KRAS-specific PROTACs and their mechanisms, clinical application, and effectiveness at targeting primary KRAS oncogenes and secondary drivers and signaling pathways contributing to therapeutic resistance. Also, the synergies between PROTACs and immunotherapies or chemotherapies are further amplified. This review also underscores PROTAC technology's promise to advance precision medicine by providing durable treatment options for KRAS-driven lung cancers. It addresses future directions for optimizing PROTAC efficacy, bioavailability, and patient-specific applications.

Pan-KRAS Inhibitors BI-2493 and BI-2865 Display Potent Antitumor Activity in Tumors with KRAS Wild-type Allele Amplification

KRASG12C selective inhibitors, such as sotorasib and adagrasib, have raised hopes of targeting other KRAS-mutant alleles in patients with cancer. We report that KRAS wild-type (WT)-amplified tumor models are sensitive to treatment with the small-molecule KRAS inhibitors BI-2493 and BI-2865. These pan-KRAS inhibitors directly target the "OFF" state of KRAS and result in potent antitumor activity in preclinical models of cancers driven by KRAS-mutant proteins. In this study, we used the high-throughput cellular viability Profiling Relative Inhibition Simultaneously in Mixtures assay to assess the antiproliferative activity of BI-2493 in a 900+ cancer cell line panel, expanding on our previous work. KRAS WT-amplified cancer cell lines, with a copy number >7, were identified as the most sensitive, across cell lines with any KRAS alterations, to our pan-KRAS inhibitors. Importantly, our data suggest that a KRAS "OFF" inhibitor is better suited to treat KRAS WT-amplified tumors than a KRAS "ON" inhibitor. KRAS WT amplification is common in patients with gastroesophageal cancers in which it has been shown to act as a unique cancer driver with little overlap to other actionable mutations. The pan-KRAS inhibitors BI-2493 and BI-2865 show potent antitumor activity in vitro and in vivo in KRAS WT-amplified cell lines from this and other tumor types. In conclusion, this is the first study to demonstrate that direct pharmacologic inhibition of KRAS shows antitumor activity in preclinical models of cancer with KRAS WT amplification, suggesting a novel therapeutic concept for patients with cancers bearing this KRAS alteration.

Precision peptide disruptors: The next generation of targeted therapeutics in oncology

Therapeutically targeting the pathologically remodelled protein-protein interaction network in cancer with peptide disruptors increasingly represents a clinically attractive approach to treating recalcitrant cancers. In this review, we map the pre-clinical and clinical-stage peptide disruptor landscape within an oncology-specific context and discuss key clinical examples that are making significant impact to patients; demonstrating a key role for peptide disruptors in precision medicine as a next-generation targeted therapeutic.

Discovery of Daraxonrasib (RMC-6236), a Potent and Orally Bioavailable RAS(ON) Multi-selective, Noncovalent Tri-complex Inhibitor for the Treatment of Patients with Multiple RAS-Addicted Cancers

Oncogenic RAS mutations are among the most common in human cancers. To target the active, GTP-bound state of RAS(ON) directly, we employed an innovative tri-complex inhibitor (TCI) modality. Formation of a complex with an intracellular chaperone protein CypA, an inhibitor, and a target protein RAS blocks effector binding, inhibiting downstream RAS signaling and tumor cell proliferation. Herein, we describe the structure-guided SAR journey that led to the discovery of daraxonrasib (RMC-6236), a noncovalent, potent tri-complex inhibitor of multiple RAS mutant and wild-type (WT) variants. This orally bioavailable bRo5 macrocyclic molecule occupies a unique composite binding pocket comprising CypA and SWI/SWII regions of RAS(ON). To achieve broad-spectrum RAS isoform activity, we deployed an SAR campaign that focused on interactions with residues conserved between mutants and WT RAS isoforms. Concurrent optimization of potency and drug-like properties led to the discovery of daraxonrasib (RMC-6236), currently in clinical evaluation in RAS mutant advanced solid tumors (NCT05379985; NCT06040541; NCT06162221; NCT06445062; NCT06128551).

KRAS G12V mutation-selective requirement for ACSS2 in colorectal adenoma formation

Oncogenic KRAS mutations are prevalent in colorectal cancer (CRC) and linked to poor prognosis and therapeutic resistance. Emerging evidence suggests that specific KRAS mutations differentially influence treatment responses. In this study, we generate isogenic Apc-null mouse colon epithelial cells with four common KRAS mutations. Transcriptomic and proteomic analyses reveal significant enrichment of cholesterol and lipid metabolism pathways in KRAS G12V cells, driven by increased SREBP1 expression and mTORC1 activation. Furthermore, KRAS G12V cells exhibit elevated ACSS2 expression and greater dependence on ACSS2 for proliferative advantage compared to other mutants. Inhibition of ACSS2 uniquely sensitizes KRAS G12V cells to MEK inhibition, highlighting a distinct therapeutic vulnerability. Finally, ACSS2 plays a critical role in early KRAS G12V adenoma development, unlike in KRAS G12D adenomas. These findings highlight mutation-specific metabolic reprogramming in KRAS-driven CRC and identify ACSS2 as a potential therapeutic target.

SOS1 inhibitor BI-3406 shows in vivo antitumor activity akin to genetic ablation and synergizes with a KRASG12D inhibitor in KRAS LUAD

We evaluated the in vivo therapeutic efficacy and tolerability of BI-3406-mediated pharmacological inhibition of SOS1 in comparison to genetic ablation of this universal Ras-GEF in various KRAS-dependent experimental tumor settings. Contrary to the rapid lethality caused by SOS1 genetic ablation in SOS2KO mice, SOS1 pharmacological inhibition by its specific inhibitor BI-3406 did not significantly affect animal weight/viability nor cause noteworthy systemic toxicity. Allograft assays using different KRASmut cell lines showed that treatment with BI-3406 impaired RAS activation and RAS downstream signaling and decreased tumor burden and disease progression as a result of both tumor-intrinsic and -extrinsic therapeutic effects of the drug. Consistent with prior genetic evidence and the KRASmut allografts assays in immunocompromised mice, our analyses using an in vivo model of KRASG12D-driven lung adenocarcinoma (LUAD) in immunocompetent mice showed that single, systemic BI-3406 treatment impaired tumor growth and downmodulated protumorigenic components of the tumor microenvironment comparably to SOS1 genetic ablation or to treatment with the specific KRASG12D inhibitor MRTX1133. Furthermore, markedly stronger, synergistic antitumor effects were observed upon concomitant treatment with BI-3406 and MRTX1133 in the same in vivo LUAD mouse model. Our data confirm SOS1 as an actionable therapy target in RAS-dependent cancers and suggest that BI-3406 treatment may yield clinical benefit both as monotherapy or as a potential combination partner for multiple RAS-targeting strategies.

Epigenetic regulatory protein chromobox family regulates multiple signalling pathways and mechanisms in cancer

Signal transduction plays a pivotal role in modulating a myriad of critical processes, including the tumour microenvironment (TME), cell cycle arrest, proliferation and apoptosis of tumour cells, as well as their migration, invasion, and the epithelial-mesenchymal transition (EMT). Epigenetic mechanisms are instrumental in the genesis and progression of tumours. The Chromobox (CBX) family proteins, which serve as significant epigenetic regulators, exhibit tumour-specific expression patterns and biological functionalities. These proteins are influenced by a multitude of factors and could modulate the activation of diverse signalling pathways within tumour cells through alterations in epigenetic modifications, thereby acting as either oncogenic agents or tumour suppressors. This review aims to succinctly delineate the composition, structure, function, and expression of CBXs within tumour cells, with an emphasis on synthesizing and deliberating the CBXs-mediated activation of intracellular signalling pathways and the intricate mechanisms governing tumourigenesis and progression. Moreover, a plethora of contemporary studies have substantiated that CBXs might represent a promising target for the diagnosis and therapeutic intervention of tumour patients. We have also compiled and scrutinized the current research landscape concerning inhibitors targeting CBXs, aspiring to aid researchers in gaining a deeper comprehension of the biological roles and mechanisms of CBXs in the malignant evolution of tumours, and to furnish novel perspectives for the innovation of targeted tumour therapeutics.

Sos1 ablation alters focal adhesion dynamics and increases Mmp2/9-dependent gelatinase activity in primary mouse embryonic fibroblasts

BACKGROUND

Sos1 and Sos2 are guanine-nucleotide exchange factors for Ras and Rac small GTPases, which are involved in a wide range of cellular responses including proliferation and migration. We have previously shown that Sos1 and Sos2 have different effects on cell migration, but the underlying mechanisms are not clear.

METHODS

Using a 4-hydroxytamoxifen-inducible conditional Sos1KO mutation, here we evaluated the functional specificity or redundancy of Sos1 and Sos2 regarding the control of cell migration and dynamics of focal adhesions (FAs) in primary mouse embryonic fibroblasts (MEFs).

RESULTS

Functional analysis of the transcriptome of primary Sos1/2WT, Sos1KO, Sos2KO and Sos1/2DKO-MEFs revealed a specific, dominant role of Sos1 over Sos2 in transcriptional regulation. Sos1KO MEFs had an increased number and stability of focal adhesions (FAs) and curbed protrusion and spreading. Conversely, Sos2KO MEFs displayed unstable FAs with increased protrusion. Interestingly, Sos1, but not Sos2, ablation reduced the levels of GTP-bound Rac at the leading edge. In 3D, however, only Sos1/2KO MEFs showed increased invasion and matrix degradative capacity, which correlated with increased expression of the Mmp2 and Mmp9 gelatinases. Moreover, increased matrix degradation in Sos1/2KO MEFs was abrogated by treatment with Mmp2/9 inhibitors.

CONCLUSIONS

Our data demonstrate that Sos1 and Sos2 have different functions in FAs distribution and dynamics in 2D whereas in 3D they act together to regulate invasion and unveil a previously undescribed mechanistic connection between Sos1/2 and the regulation of Mmp2/9 expression in primary MEFs.

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.

Genome-wide CRISPR screening identifies PHF8 as an effective therapeutic target for KRAS- or BRAF-mutant colorectal cancers

BACKGROUND

Mutations in KRAS and BRAF genes are prevalent in colorectal cancer (CRC), which strikingly promote tumorigenesis and lead to poor response to a variety of treatments including immunotherapy by activating the MAPK/ERK pathway. Thus, there is an urgent need to discover effective therapeutic targets and strategies.

METHODS

CRISPR-Cas9 lentiviral knockout library was used to screen the suppressors of anti-PD1 immunotherapy. Bioinformatic analysis was used to analyze the correlation between PHF8 expression and immune indicators in CRC. In vitro and in vivo experiments were utilized to determine the effects of PHF8 on the immune indexes and malignant phenotypes of CRC cells. qRT-PCR, western blotting, immunohistochemical (IHC) staining, and chromatin immunoprecipitation (ChIP)-qPCR assays were used to determine the regulatory effects of PHF8 on PD-L1, KRAS, BRAF, and c-Myc and the regulatory effect c-Myc/miR-22-3p signaling axis on PHF8 expression in CRC cells.

RESULTS

This study identified histone lysine demethylase PHF8 as a negative regulator for the efficacy of anti-PD1 therapy and found that it was highly expressed in CRCs and strongly associated with poor patient survival. Functional studies showed that PHF8 played an oncogenic role in KRAS- or BRAF-mutant CRC cells, but not in wild-type ones. Mechanistically, PHF8 up-regulated the expression of PD-L1, KRAS, BRAF, and c-Myc by increasing the levels of transcriptional activation marks H3K4me3 and H3K27ac and decreasing the levels of transcriptional repression mark H3K9me2 within their promoter regions, promoting immune escape and tumor progression. Besides, our data also demonstrated that PHF8 was up-regulated by the c-Myc/miR-22-3p signaling axis to form a positive feedback loop. Targeting PHF8 substantially improved the efficacy of anti-PD1 therapy and inhibited the malignant phenotypes of KRAS- or BRAF-mutant CRC cells.

CONCLUSION

Our data demonstrate that PHF8 may be an effective therapeutic target for KRAS- or BRAF-mutant CRCs.

Cost-effectiveness analysis of nimotuzumab combined with gemcitabine for K-Ras wild type locally advanced or metastatic pancreatic cancer in China

The phase III NOTABLE trial has revealed that nimotuzumab plus gemcitabine achieves greater clinical benefit in the first-line treating K-Ras wild type locally advanced (LA) or metastatic pancreatic cancer (mPC), compared to gemcitabine. Hence, herein, we examined the cost-efficiency of introducing nimotuzumab to gemcitabine, relative to gemcitabinealone, in first-line K-Ras wild type LA or mPC therapy from a Chinese payer perspective. We generated an exhaustive decision-analytical Markov model using three exclusive health states to incorporate both clinical and economic consequences of nimotuzumab plus gemcitabine versus gemcitabine alone as first-line therapy patients with K-Ras wild type LA or mPC. Using a 10-year lifetime horizon, we assessed the total medical expenditure, quality-adjusted life years (QALYs), and incremental cost‒effectiveness ratio (ICER) as the primary surrogate outcomes of our model. Sensitivity analyses were conducted via alteration of internally tweakable parameters, and further subgroup analyses were conducted as needed. The overall health surrogate outcomes were 2.94 QALYs ($215,799) among patients with nimotuzumab plus gemcitabine and 1.83 QALYs ($86,039) among patients with gemcitabine alone (ICER value, $117,263/QALY; Incremental net health benefit [INHB] value, - 2.46/QALY). Based on our sensitivity analysis, among all parameters, progression-free survival (PFS) utility was of utmost importance, and it exerted a considerable impact on our model. The ICER consistently well exceeded the willingness-to-pay (WTP) threshold and negative INHBs were observed across all patient subcategories with zero alteration recorded as cost-effective in the subgroup analyses. Nimotuzumab plus gemcitabine, relative to gemcitabine alone, is not a cost-effective first-line treatment among patients with K-Ras wild type LA or mPC at the current prices offered in China.

Innovative design and potential applications of covalent strategy in drug discovery

Covalent inhibitors provide persistent inhibition while maintaining excellent selectivity and efficacy by creating stable covalent connections with specific amino acids in target proteins. This technique enables the precise inhibition of previously undruggable targets, lowering the frequency of administration and potentially bypassing drug resistance. Because of these advantages, covalent inhibitors have tremendous potential in treating cancer, inflammation, and infectious illnesses, making them extremely important in modern pharmacological research. Covalent inhibitors targeting EGFR, BTK, and KRAS (G12X), which overcome drug resistance and off-target, non-"medicinal" difficulties, as well as covalent inhibitors targeting SARS-CoV-2 Mpro, have paved the way for the development of new antiviral medicines. Furthermore, the use of covalent methods in drug discovery procedures, such as covalent PROTACs, covalent molecular gels, covalent probes, CoLDR, and Dual-targeted covalent inhibitors, preserves these tactics' inherent features while incorporating the advantages of covalent inhibitors. This synthesis opens up new therapeutic opportunities. This review comprehensively examines the use of covalent techniques in drug discovery, emphasizing their transformational potential for future drug development.

Oncogenic mutant KRAS inhibition through oxidation at cysteine 118

Specific reactive oxygen species activate the GTPase Kirsten rat sarcoma virus (KRAS) by reacting with cysteine 118 (C118), leading to an electron transfer between C118 and nucleoside guanosine diphosphate (GDP), which causes the release of GDP. Here, we have mimicked permanent oxidation of human KRAS at C118 by replacing C118 with aspartic acid (C118D) in KRAS to show that oncogenic mutant KRAS is selectively inhibited via oxidation at C118, both in vitro and in vivo. Moreover, the combined treatment of hydrogen-peroxide-producing pro-oxidant paraquat and nitric-oxide-producing inhibitor N(ω)-nitro-l-arginine methyl ester selectively inhibits human mutant KRAS activity by inducing oxidization at C118. Our study shows for the first time the vulnerability of human mutant KRAS to oxidation, thereby paving the way to explore oxidation-based anti-KRAS treatments in humans.

KRAS inhibitors: resistance drivers and combinatorial strategies

In 1982, the RAS genes HRAS and KRAS were discovered as the first human cancer genes, with KRAS later identified as one of the most frequently mutated oncogenes. Yet, it took nearly 40 years to develop clinically effective inhibitors for RAS-mutant cancers. The discovery in 2013 by Shokat and colleagues of a druggable pocket in KRAS paved the way to FDA approval of the first covalently binding KRASG12C inhibitors, sotorasib and adagrasib, in 2021 and 2022, respectively. However, rather than marking the end of a successful assault on the Mount Everest of cancer research, this landmark only revealed new challenges in RAS drug discovery. In this review, we highlight the progress on defining resistance mechanisms and developing combination treatment strategies to improve patient responses to KRAS therapies.

Targeting secretory autophagy in solid cancers: mechanisms, immune regulation and clinical insights

Secretory autophagy is a classical form of unconventional secretion that integrates autophagy with the secretory process, relying on highly conserved autophagy-related molecules and playing a critical role in tumor progression and treatment resistance. Traditional autophagy is responsible for degrading intracellular substances by fusing autophagosomes with lysosomes. However, secretory autophagy uses autophagy signaling to mediate the secretion of specific substances and regulate the tumor microenvironment (TME). Cytoplasmic substances are preferentially secreted rather than directed toward lysosomal degradation, involving various selective mechanisms. Moreover, substances released by secretory autophagy convey biological signals to the TME, inducing immune dysregulation and contributing to drug resistance. Therefore, elucidating the mechanisms underlying secretory autophagy is essential for improving clinical treatments. This review systematically summarizes current knowledge of secretory autophagy, from initiation to secretion, considering inter-tumor heterogeneity, explores its role across different tumor types. Furthermore, it proposes future research directions and highlights unresolved clinical challenges.

KRASG 12C-inhibitor-based combination therapies for pancreatic cancer: insights from drug screening

Pancreatic ductal adenocarcinoma (PDAC) has limited treatment options, emphasizing the urgent need for effective therapies. The predominant driver in PDAC is mutated KRAS proto-oncogene, KRA, present in 90% of patients. The emergence of direct KRAS inhibitors presents a promising avenue for treatment, particularly those targeting the KRASG12C mutated allele, which show encouraging results in clinical trials. However, the development of resistance necessitates exploring potent combination therapies. Our objective was to identify effective KRASG12C-inhibitor combination therapies through unbiased drug screening. Results revealed synergistic effects with son of sevenless homolog 1 (SOS1) inhibitors, tyrosine-protein phosphatase non-receptor type 11 (PTPN11)/Src homology region 2 domain-containing phosphatase-2 (SHP2) inhibitors, and broad-spectrum multi-kinase inhibitors. Validation in a novel and unique KRASG12C-mutated patient-derived organoid model confirmed the described hits from the screening experiment. Our findings propose strategies to enhance KRASG12C-inhibitor efficacy, guiding clinical trial design and molecular tumor boards.

Breathing new insights into the role of mutant p53 in lung cancer

The tumour suppressor gene p53 is one of the most frequently mutated genes in lung cancer and these defects are associated with poor prognosis, albeit some debate exists in the lung cancer field. Despite extensive research, the exact mechanisms by which mutant p53 proteins promote the development and sustained expansion of cancer remain unclear. This review will discuss the cellular responses controlled by p53 that contribute to tumour suppression, p53 mutant lung cancer mouse models and characterisation of p53 mutant lung cancer. Furthermore, we discuss potential approaches of targeting mutant p53 for the treatment of lung cancer.

Novel potent SOS1 inhibitors containing a tricyclic quinazoline scaffold: A joint view of experiments and simulations

Small molecules that possess the ability to regulate the interactions between Son of Sevenless 1 (SOS1) and Kristen rat sarcoma (KRAS) offer immense potential in the realm of cancer therapy. In this study, we present a novel series of SOS1 inhibitors featuring a tricyclic quinazoline scaffold. Notably, we have identified compound 8d, which demonstrates the highest potency with an IC50 value of 5.1 nM for disrupting the KRAS:SOS1 interaction. Compound 8d exhibits a promising pharmacokinetic profile and achieves a remarkable 70.5 % inhibition of tumor growth in pancreas tumor xenograft models. Furthermore, molecular dynamic simulations have unveiled that the tricyclic quinazoline derivatives exhibit extensive interaction with Tyr884, a crucial residue for the recognition between SOS1 and KRAS. Our findings provide fresh insights into the design of future SOS1 inhibitors, paving the way for innovative therapeutic strategies.

The roles of KRAS in cancer metabolism, tumor microenvironment and clinical therapy

KRAS is one of the most mutated genes, driving alternations in metabolic pathways that include enhanced nutrient uptaking, increased glycolysis, elevated glutaminolysis, and heightened synthesis of fatty acids and nucleotides. However, the beyond mechanisms of KRAS-modulated cancer metabolisms remain incompletely understood. In this review, we aim to summarize current knowledge on KRAS-related metabolic alterations in cancer cells and explore the prevalence and significance of KRAS mutation in shaping the tumor microenvironment and influencing epigenetic modification via various molecular activities. Given that cancer cells rely on these metabolic changes to sustain cell growth and survival, targeting these processes may represent a promising therapeutic strategy for KRAS-driven cancers.

Zongertinib (BI 1810631), an Irreversible HER2 TKI, Spares EGFR Signaling and Improves Therapeutic Response in Preclinical Models and Patients with HER2-Driven Cancers

Mutations in ERBB2 (encoding HER2) occur in 2% to 4% of non-small cell lung cancer (NSCLC) and confer poor prognosis. ERBB-targeting tyrosine kinase inhibitors, approved for treating other HER2-dependent cancers, are ineffective in HER2-mutant NSCLC due to dose-limiting toxicities or suboptimal potency. We report the discovery of zongertinib (BI 1810631), a covalent HER2 inhibitor. Zongertinib potently and selectively blocks HER2, while sparing EGFR, and inhibits the growth of cells dependent on HER2 oncogenic driver events, including HER2-dependent human cancer cells resistant to trastuzumab deruxtecan. Zongertinib displays potent antitumor activity in HER2-dependent human NSCLC xenograft models and enhances the activities of antibody-drug conjugates and KRASG12C inhibitors without causing obvious toxicities. The preclinical efficacy of zongertinib translates in objective responses in patients with HER2-dependent tumors, including cholangiocarcinoma (SDC4-NRG1 fusion) and breast cancer (V777L HER2 mutation), thus supporting the ongoing clinical development of zongertinib. Significance: HER2-mutant NSCLC poses a challenge in the clinic due to limited options for targeted therapies. Pan-ERBB blockers are limited by wild-type EGFR-mediated toxicity. Zongertinib is a highly potent and wild-type EGFR-sparing HER2 inhibitor that is active in HER2-driven tumors in the preclinical and clinical settings.

Advances in Novel Targeted Therapies for Pancreatic Adenocarcinoma

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy with limited therapeutic options and poor prognosis. Recent advances in targeted therapies have opened new avenues for intervention in PDAC, focusing on key genetic and molecular pathways that drive tumor progression.

METHODS

In this review, we provide an overview on advances in novel targeted therapies in pancreatic adenocarcinoma.

RESULTS

Here, we explore the latest development in targeting the KRAS pathway, a historically "undruggable" target crucial to PDAC pathogenesis. Strategies to inhibit KRAS include direct KRAS-targeted therapies, modulation of upstream and downstream signaling, KRAS-specific siRNA, and novel combination therapies integrating KRAS inhibitors with immune checkpoint blockade, PARP inhibitors, chemotherapy, CDK4/6 inhibitors, and autophagy modulators. Beyond KRAS, emerging targets such as NRG1 fusions, NTRK/ROS1 fusions, RET alterations, and the PRMT5/CDKN2A/MAT2A axis, along with EGFR and Claudin18.2 inhibitors, are also discussed as promising therapeutic strategies. Additionally, the review highlights novel approaches for microsatellite instability-high (MSIH) PDAC and emerging therapies, including adoptive cell therapies (CAR-T, TCR, TIL), cancer vaccines, and strategies to modify the tumor microenvironment.

CONCLUSION

Overall, the rapid evolution of targeted therapies offers renewed optimism in the fight against pancreatic cancer, a malignancy with historically poor outcomes.

KRAS Mutation Status and Treatment Outcomes in Patients With Metastatic Pancreatic Adenocarcinoma

Importance

Despite the high prevalence of KRAS alterations in pancreatic ductal adenocarcinoma (PDAC), the clinical impact of common KRAS mutations with different cytotoxic regimens is unknown. This evidence is important to inform current treatment and provide a benchmark for emergent targeted KRAS therapies in metastatic PDAC.

Objective

To assess the clinical implications of common KRAS G12 mutations in PDAC and to compare outcomes of standard-of-care multiagent therapies across these common mutations.

Design, Setting, and Participants

This retrospective cohort study obtained deidentified clinical data for 5382 patients from a nationwide (US-based) clinicogenomic database. The deidentified data originated from approximately 280 US cancer clinics (approximately 800 sites of care). Patients diagnosed with metastatic PDAC from February 9, 2010, to September 20, 2022, and with sufficient follow-up and treatment data were included.

Main Outcomes and Measures

Median overall survival (OS) and time to next treatment (TTNT) were calculated for each KRAS mutation group. Hazard ratios (HRs) were generated using multivariate Cox proportional hazards models for KRAS mutations and mutation-treatment combinations.

Results

A total of 2433 patients with PDAC were included in the analysis (mean age at first treatment, 67.0 [range, 66.0-68.0] years; 1340 male [55.1%]). Among 2023 patients with KRAS mutations, those with G12R had the longest median TTNT (6.0 [95% CI, 5.2-6.6] months) and the longest median OS (13.2 [95% CI, 10.6-15.2] months). Patients with KRAS G12D and G12V mutations had a significantly higher risk of disease progression (HRs, 1.15; [95% CI, 1.04-1.29; P = .009] and 1.16 [95% CI, 1.04-1.30; P = .01], respectively) and death (HRs, 1.29 [95% CI, 1.15-1.45; P < .001] and 1.23 [95% CI, 1.09-1.39; P < .001], respectively) compared with KRAS wild type. The FOLFIRINOX regimen (fluorouracil, irinotecan, oxaliplatin, and leucovorin) had a significantly lower risk of treatment progression and death than gemcitabine with (HRs, 1.19 [95% CI, [1.09-1.29; P < .001] and 1.18 [95% CI, 1.07-1.29; P < .001], respectively) or without (HRs, 1.37 [95% CI, 1.11-1.69; P = .003] and 1.41 [95% CI 1.13-1.75; P = .002], respectively) nab-paclitaxel across all patients.

Conclusions and Relevance

In this cohort study of 2433 patients with PDAC, KRAS G12D and G12V mutations were associated with worse patient outcomes compared with KRAS wild type. KRAS G12R was associated with more favorable patient outcomes, and FOLFIRINOX was associated with better patient outcomes than gemcitabine-based therapies. These findings highlight the need for more effective systemic therapies for these groups of patients.

Late-line options for patients with metastatic colorectal cancer: a review and evidence-based algorithm

Over the past few years, several novel systemic treatments have emerged for patients with treatment-refractory metastatic colorectal cancer, thus making selection of the most effective later-line therapy a challenge for medical oncologists. Over the past decade, regorafenib and trifluridine-tipiracil were the only available drugs and often provided limited clinical benefit compared to best supportive care. Results from subsequent practice-changing trials opened several novel therapeutic avenues, both for unselected patients (such as trifluridine-tipiracil plus bevacizumab or fruquintinib) and for subgroups defined by the presence of actionable alterations in their tumours (such as HER2-targeted therapies or KRASG12C inhibitors) or with no acquired mechanisms of resistance to the previously received targeted agents in circulating tumour DNA (such as retreatment with anti-EGFR antibodies). In this Review, we provide a comprehensive overview of advances in the field over the past few years and offer a practical perspective on translation of the most relevant results into the daily management of patients with metastatic colorectal cancer using an evidence-based algorithm. Finally, we discuss some of the most appealing ongoing areas of research and highlight approaches with the potential to further expand the therapeutic armamentarium.

Plasticity and Tumor Microenvironment in Pancreatic Cancer: Genetic, Metabolic, and Immune Perspectives

Cancer has long been believed to be a genetic disease caused by the accumulation of mutations in key genes involved in cellular processes. However, recent advances in sequencing technology have demonstrated that cells with cancer driver mutations are also present in normal tissues in response to aging, environmental damage, and chronic inflammation, suggesting that not only intrinsic factors within cancer cells, but also environmental alterations are important key factors in cancer development and progression. Pancreatic cancer tissue is mostly comprised of stromal cells and immune cells. The desmoplasmic microenvironment characteristic of pancreatic cancer is hypoxic and hypotrophic. Pancreatic cancer cells may adapt to this environment by rewiring their metabolism through epigenomic changes, enhancing intrinsic plasticity, creating an acidic and immunosuppressive tumor microenvironment, and inducing noncancerous cells to become tumor-promoting. In addition, pancreatic cancer has often metastasized to local and distant sites by the time of diagnosis, suggesting that a similar mechanism is operating from the precancerous stage. Here, we review key recent findings on how pancreatic cancers acquire plasticity, undergo metabolic reprogramming, and promote immunosuppressive microenvironment formation during their evolution. Furthermore, we present the following two signaling pathways that we have identified: one based on the small G-protein ARF6 driven by KRAS/TP53 mutations, and the other based on the RNA-binding protein Arid5a mediated by inflammatory cytokines, which promote both metabolic reprogramming and immune evasion in pancreatic cancer. Finally, the striking diversity among pancreatic cancers in the relative importance of mutational burden and the tumor microenvironment, their clinical relevance, and the potential for novel therapeutic strategies will be discussed.

Diosmin reduces the stability of Snail and Cyclin D1 by targeting FAK to inhibit NSCLC progression

BACKGROUND

In different tumours, focal adhesion kinase (FAK), a nonreceptor tyrosine kinase, is upregulated and hence, it represents a promising target for cancer therapy. However, the development of FAK kinase inhibitors has faced a number of challenges. It is therefore imperative that new, effective FAK kinase inhibitors be identified promptly.

METHODS

Small molecules that target FAK were identified through molecular docking and validated through surface plasmon resonance (SPR) and cell thermal shift analysis. We investigated the pharmacological effects of FAK kinase inhibitors using CCK-8, colony formation, EdU, and Transwell assays and cell cycle analysis. The molecular mechanism was determined via methods such as coimmunoprecipitation, RNA pull-down and RNA immunoprecipitation.

RESULTS

Here, we confirmed that diosmin (Dio) is an inhibitor of FAK and demonstrated its anti-proliferative and anti-metastatic effects in lung adenocarcinoma. Mechanistically, Dio inhibited tumour proliferation and metastasis by impeding the catalytic activity of FAK. Dio activated the ubiquitin proteasome pathway to induce Cyclin D1 degradation, while inhibiting tumour proliferation and reversing the epithelial mesenchymal transition (EMT) process by reducing the mRNA stability of Snail, thereby inhibiting cancer metastasis. In addition, the inhibitory effect of Dio on lung adenocarcinoma was validated in a mouse xenograft model.

CONCLUSION

These results support the tumour-promoting role of FAK in lung adenocarcinoma by stabilizing Cyclin D1 and Snail and suggest that Dio is a promising candidate for FAK inhibition.

Characterization of the BH1406 non-small cell lung cancer (NSCLC) cell line carrying an activating SOS1 mutation

Background

Approximately 30% of the non-small cell lung cancer (NSCLC) patients which harbor no recognizable oncogenic driver mutation are not eligible for targeted therapy. Functional drug screening of tumor cells helps to identify susceptible drug targets not recognized by gene panels for targeted mutation analysis. The aim of this study is to characterize the BH1406 cell line carrying an activating SOS1 mutation and to check its sensitivity to cognate inhibitors.

Methods

The NSCLC cell line BH1406 was established from a pleural effusion and found to be sensitive to the SOS1 inhibitor BAY-293 in initial viability screenings. Since in a limited next-generation sequencing (NGS) lung cancer mutation panel no driver could be detected, the patient underwent chemotherapy with poor outcome. This cell line was further characterized by exome sequencing, SOS1 Western blotting, comparison of two-dimensional (2D) and three-dimensional (3D) chemosensitivity assays and phosphoprotein arrays.

Results

In whole-exome sequencing (WES) the SOS1 mutation P481delinsLFFL, positioned near the known P478L activating mutation was detected. Besides BAY-293, BH1406 cells proved to be sensitive to the SOS1 inhibitors MRTX0902 and BI-3406. The sensitivity of BH1406 cells to BI-3406 was increased under 3D conditions compared to 2D cultures. Western blot phosphoprotein arrays revealed reduced phosphorylation of CREB, GSK3, CHK-2 and STAT3 in BH1406 by BAY-293 treatment in 2D culture. In 3D conditions, cells switched from GSK3α to elevated ERK1/2 signaling, again blocked by the SOS1 inhibitor BAY-293. Similar results were obtained for the SOS1 inhibitors MRTX0902 and BI3406. Additionally, the PI3K inhibitor dactolisib, the GSK-3 inhibitor BI-5521 as well as the bromodomain protein-directed PROTAC ARV-771 inhibited the growth of BH1406 cells significantly and showed synergistic interaction with BAY-293. Furthermore, Western blots demonstrated reduced expression of SOS1 and MYC proteins in response to BAY-293 treatment.

Conclusions

The rare SOS1 P481delinsLFFL mutation in lung cancer may be targetable with corresponding inhibitors, alone or in combination with GSK3/PI3K/BET inhibitors. BH1406 cells represent a novel cellular model suitable for the molecular characterization of SOS1 druggability. Such rare oncogenic driver genes are not included in standard NGS panels and need to be detected by expanded assays like WES.

Insights into direct KRAS inhibition strategies for cancer treatment

KRAS is the most commonly mutated isoform in RAS-driven cancers. In the early stage, KRAS was deemed as an "undruggable" cancer target due to the lack of suitable binding pockets. With the development of KRAS inhibitors in recent years, strategies that directly suppress oncogenic KRAS have achieved significant breakthroughs. In this review, we summarize recent advances in direct small-molecule KRAS inhibitors used for cancer therapy, highlighting their medicinal chemistry optimization processes. Moreover, new PROTACs targeting the KRAS mutation are also presented. Additionally, we put forward the challenges and prospects for the development of future KRAS inhibitors.

Performance evaluation of a CRISPR Cas9-based selective exponential amplification assay for the detection of KRAS mutations in plasma of patients with advanced pancreatic cancer

AIMS

Pancreatic ductal adenocarcinoma (PDAC) is highly malignant, with shockingly mortality rates. KRAS oncoprotein is the main molecular target for PDAC. Liquid biopsies, such as the detection of circulating tumour DNA (ctDNA), offer a promising approach for less invasive diagnosis. In this study, we aim to evaluate the precision and utility of programmable enzyme-based selective exponential amplification (PASEA) assay for rare mutant alleles identification.

METHODS

PASEA uses CRISPR-Cas9 to continuously shear wild-type alleles during recombinase polymerase amplification, while mutant alleles are exponentially amplified, ultimately reaching a level detectable by Sanger sequencing. We applied PASEA to detect KRAS mutations in plasma ctDNA. A total of 153 patients with stage IV PDAC were enrolled. We investigated the relationship between ctDNA detection rates with various clinical factors.

RESULTS

Our results showed 91.43% vs 44.83% detection rate in patients of prechemotherapy and undergoing chemotherapy. KRAS ctDNA was more prevalent in patients with liver metastases and patients did not undergo surgical resection. Patients with liver metastases prior to chemotherapy showed a sensitivity of 95.24% (20/21) with PASEA. Through longitudinal monitoring, we found ctDNA may be a more accurate biomarker for monitoring chemotherapy efficacy in PDAC than CA19-9.

CONCLUSIONS

Our study sheds light on the potential of ctDNA as a valuable complementary biomarker for precision targeted therapy, emphasising the importance of considering chemotherapy status, metastatic sites and surgical history when evaluating its diagnostic potential in PDAC. PASEA technology provides a reliable, cost-effective and minimally invasive method for detecting ctDNA of PDAC.

Next generation sequencing and genomic mapping: towards precision molecular diagnosis of lung cancer in Morocco

Introduction

lung cancer is the leading cause of cancer-related deaths worldwide, with a significant incidence in Morocco. The complex epidemiology of this disease in the country necessitates an in-depth analysis of genetic profiles to improve diagnosis and treatment. This study utilizes next-generation sequencing (NGS) to map genetic alterations in Moroccan patients with lung cancer, a field where molecular data is largely lacking. Importantly, this study presents a pioneering analysis of lung cancer in the Moroccan population using next-generation sequencing technology. While previous studies focused on a limited number of genes, our research provides a comprehensive and detailed perspective on the genetic alterations within this cohort, including the generation of an oncoprint.

Methods

this study involved 100 histologically confirmed lung cancer patients. Genetic abnormalities were detected using the NGS technique with the Oncomine Precision Assay GX protocol. Lung biopsy samples were prepared, purified, and sequenced, with the resulting data analyzed to identify significant genetic variants.

Results

the analysis revealed genetic alterations in 13 different genes, with a notable prevalence of mutations in the TP53, KRAS, and Epithelial Growth Factor Receptor (EGFR) genes. TP53 mutations were present in 27% of cases, while KRAS and EGFR showed mutations in 19% and 14% of samples, respectively. Clinically significant mutations were also identified in the ALK, MET, ERBB2, and ROS1 genes, highlighting substantial genomic diversity in this cohort.

Conclusion

the results of this study enhance the understanding of genetic alterations in Moroccan lung cancer patients and underscore the need to strengthen efforts for advanced molecular diagnosis in Morocco. The use of NGS has identified critical genetic mutations, facilitating the development of personalized treatments and improving clinical outcomes. These findings pave the way for future research aimed at refining diagnostic and therapeutic strategies, thereby contributing to better patient management.

Evaluation of SNaPshot and Sanger sequencing for the detection of KRAS and NRAS mutations in a sample of Venezuelan patients with colorectal cancer

Colorectal cancer (CRC) is the third most commonly occurring cancer in men and the second most commonly occurring cancer in women. The epidermal growth factor receptor (EGFR) is relevant in the development and progression of CRC, because it is part of multiple signaling pathways involved in processes of the cell cycle, their malfunction causes dysregulation and subsequently carcinogenesis. Consequently, therapies were developed with anti-EGFR monoclonal antibodies (MAbs) that improve the survival of patients with CRC. However, mutations in the oncogenes Kirsten rat sarcoma (KRAS) and Neuroblastoma RAS (NRAS), modulators of the EGFR signaling pathway (downstream) activate a pathway independent in which such drugs have no effect. Patients with these mutations have a low response to MAb therapies. In this research, the SNaPshot sequencing method was used for the first time in Venezuela for the diagnosis of mutations in exon 2 of the KRAS and NRAS genes, from DNA extracted from tumor tissue samples fixed with formalin and included in paraffin (FFPE) and was compared with Sanger's method to determine the specificity and sensitivity, in the detection of mutations in the KRAS and NRAS genes. Of the 33 samples analysed, 27.3% presented mutations in KRAS and 15.1% in NRAS. With the obtained, it was carried out for the first time in the country the assignment of the geographical distribution of the polymorphisms found in these genes. The mutational status of the KRAS and NRAS genes showed no relationship statistically significant with clinical-histopathological variables. For this study, the SNaPshot method showed greater accuracy, sensitivity and specificity in the detection of single nucleotide polymorphisms than the Sanger method.

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.

Targeting BCL2 with Venetoclax Enhances the Efficacy of the KRASG12D Inhibitor MRTX1133 in Pancreatic Cancer

MRTX1133 is currently being evaluated in patients with pancreatic ductal adenocarcinoma (PDAC) tumors harboring a KRASG12D mutation. Combination strategies have the potential to enhance the efficacy of MRTX1133 to further promote cell death and tumor regression. In this study, we demonstrated that MRTX1133 increased the levels of the proapoptotic protein BIM in PDAC cells and conferred sensitivity to the FDA-approved BCL2 inhibitor venetoclax. Combined treatment with MRTX1133 and venetoclax resulted in cell death and growth suppression in 3D cultures. BIM was required for apoptosis induced by the combination treatment. Consistently, BIM was induced in tumors treated with MRTX1133, and venetoclax enhanced the efficacy of MRTX1133 in vivo. Venetoclax could also resensitize MRTX1133-resistant PDAC cells to MRTX1133 in 3D cultures, and tumors established from resistant cells responded to the combination of MRTX1133 and venetoclax. These results provide a rationale for the clinical testing of MRTX1133 and venetoclax in patients with PDAC. Significance: The combination of MRTX1133 and the FDA-approved drug venetoclax promotes cancer cell death and tumor regression in pancreatic ductal adenocarcinoma, providing rationale for testing venetoclax with KRASG12D inhibitors in patients with pancreatic cancer.

Cultures derived from pancreatic cancer xenografts with long-term gemcitabine treatment produce chemoresistant secondary xenografts: Establishment of isogenic gemcitabine-sensitive and -resistant models

In attempts to establish sophisticated models to reproduce the process of acquired drug resistance, we transformed normal human pancreatic ductal epithelial cells by introducing genes for multiple cellular factors. We also created isogenic gemcitabine-sensitive and -resistant models by short- and long-term gemcitabine treatment, respectively. These models demonstrated differences in drug resistance in vivo, but not in vitro. Gemcitabine treatment also induced squamous transdifferentiation in xenografts in mice. The transcription factor p63 was identified as a possible resistance-determining factor but was unlikely to be solely responsible for the resistance to gemcitabine. This system would prove useful to discover novel molecular targets to overcome chemotherapy resistance, by allowing the evaluation of molecules of interest in xenograft models after in vitro genetic ablation.

Pancreatic ductal adenocarcinoma cells reshape the immune microenvironment: Molecular mechanisms and therapeutic targets

Pancreatic ductal adenocarcinoma (PDAC) is a digestive system malignancy characterized by challenging early detection, limited treatment alternatives, and generally poor prognosis. Although there have been significant advancements in immunotherapy for hematological malignancies and various solid tumors in recent decades, with impressive outcomes in recent preclinical and clinical trials, the effectiveness of these therapies in treating PDAC continues to be modest. The unique immunological microenvironment of PDAC, especially the abnormal distribution, complex composition, and variable activation states of tumor-infiltrating immune cells, greatly restricts the effectiveness of immunotherapy. Undoubtedly, integrating data from both preclinical models and human studies helps accelerate the identification of reliable molecules and pathways responsive to targeted biological therapies and immunotherapies, thereby continuously optimizing therapeutic combinations. In this review, we delve deeply into how PDAC cells regulate the immune microenvironment through complex signaling networks, affecting the quantity and functional status of immune cells to promote immune escape and tumor progression. Furthermore, we explore the multi-modal immunotherapeutic strategies currently under development, emphasizing the transformation of the immunosuppressive environment into an anti-tumor milieu by targeting specific molecular and cellular pathways, providing insights for the development of novel treatment strategies.

Unraveling the CDK9/PP2A/ERK Network in Transcriptional Pause Release and Complement Activation in KRAS-mutant Cancers

Selective inhibition of the transcription elongation factor (P-TEFb) complex represents a promising approach in cancer therapy, yet CDK9 inhibitors (CDK9i) are currently limited primarily to certain hematological malignancies. Herein, while initial responses to CDK9-targeted therapies are observed in vitro across various KRAS-mutant cancer types, their efficacy is far from satisfactory in nude mouse xenograft models. Mechanistically, CDK9 inhibition leads to compensatory activation of ERK-MYC signaling, accompanied by the recovery of proto-oncogenes, upregulation of immediate early genes (IEGs), stimulation of the complement C1r-C3-C3a cascade, and induction of tumor immunosuppression. The "paradoxical" regulation of PP2Ac activity involving the CDK9/Src interplay contributes to ERK phosphorylation and pause-release of RNA polymerase II (Pol II). Co-targeting of CDK9 and KRAS/MAPK signaling pathways eliminates ERK-MYC activation and prevents feedback activation mediated by receptor tyrosine kinases, leading to more effective control of KRAS-mutant cancers and overcoming KRASi resistance. Moreover, modulating the tumor microenvironment (TME) by complement system intervention enhances the response to CDK9i and potently suppresses tumor growth. Overall, the preclinical investigations establish a robust framework for conducting clinical trials employing KRASi/SOS1i/MEKi or immunomodifiers in combination with CDK9i to simultaneously target cancer cells and their crosstalk with the TME, thereby yielding improved responses in KRAS-mutant patients.

Comprehensive structure-function analysis reveals gain- and loss-of-function mechanisms impacting oncogenic KRAS activity

To dissect variant-function relationships in the KRAS oncoprotein, we performed deep mutational scanning (DMS) screens for both wild-type and KRASG12D mutant alleles. We defined the spectrum of oncogenic potential for nearly all possible KRAS variants, identifying several novel transforming alleles and elucidating a model to describe the frequency of KRAS mutations in human cancer as a function of transforming potential, mutational probability, and tissue-specific mutational signatures. Biochemical and structural analyses of variants identified in a KRASG12D second-site suppressor DMS screen revealed that attenuation of oncogenic KRAS can be mediated by protein instability and conformational rigidity, resulting in reduced binding affinity to effector proteins, such as RAF and PI3-kinases, or reduced SOS-mediated nucleotide exchange activity. These studies define the landscape of single amino acid alterations that modulate the function of KRAS, providing a resource for the clinical interpretation of KRAS variants and elucidating mechanisms of oncogenic KRAS inactivation for therapeutic exploitation.

KRAS, a New Target for Precision Medicine in Colorectal Cancer?

Colorectal cancer (CRC) remains a leading cause of cancer-related mortality globally, with significant public health concerns. This review examines the landscape of KRAS inhibition in colorectal cancer (CRC), focusing on recent advances in therapeutic strategies targeting this oncogene. Historically deemed undruggable due to its complex structure and essential role in tumorigenesis, KRAS mutations are prevalent in CRC and are associated with poor prognosis. However, breakthroughs in drug development have led to the emergence of KRAS inhibitors as promising treatment options. This review discusses various classes of KRAS inhibitors, including covalent and non-covalent inhibitors, as well as combination therapies aimed at enhancing efficacy and overcoming resistance mechanisms. It highlights recent clinical trials evaluating the efficacy of KRAS inhibitors either as monotherapy or in combination with other agents, such as anti-EGFR antibodies. Despite challenges such as resistance mechanisms and tumor heterogeneity, the development of KRAS inhibitors represents a significant advance in CRC treatment and holds promise for improving patient outcomes in the future.

Prognostic Role of Specific KRAS Mutations Detected in Aspiration and Liquid Biopsies from Patients with Pancreatic Cancer

Background/Objectives: Although the overall survival prognosis of patients in advanced stages of pancreatic ductal adenocarcinoma (PDAC) is poor, typically ranging from days to months from diagnosis, there are rare cases of patients remaining in therapy for longer periods of time. Early estimations of survival prognosis would allow rational decisions on complex therapy interventions, including radical surgery and robust systemic therapy regimens. Understandably, there is great interest in finding prognostic markers that can be used for patient stratification. We determined the role of various KRAS mutations in the prognosis of PDAC patients using biopsy samples and circulating tumor DNA. Methods: A total of 118 patients with PDAC, clinically confirmed by endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNB), were included in the study. DNA was extracted from cytological slides following a standard cytology evaluation to ensure adequacy (viability and quantity) and to mark the tumor cell fraction. Circulating tumor DNA (ctDNA) was extracted from plasma samples of 45 patients in stage IV of the disease. KRAS mutations in exons 12 and 13 were detected by denaturing capillary electrophoresis (DCE), revealing a minute presence of mutation-specific heteroduplexes. Kaplan-Meier survival curves were calculated for individual KRAS mutation types. Results:KRAS mutations were detected in 90% of tissue (106/118) and 44% of plasma (20/45) samples. All mutations were localized at exon 2, codon 12, with G12D (GGT > GAT) being the most frequent at 44% (47/106) and 65% (13/20), followed by other types including G12V (GGT > GTT) at 31% (33/106) and 10% (2/20), G12R (GGT > CGT) at 17% (18/106) and 10% (2/20), G12C (GGT/TGT) at 5% (5/106) and 0% (0/20) and G12S (GGT/AGT) at 1% (1/106) and 5% (1/20) in tissue and plasma samples, respectively. Two patients had two mutations simultaneously (G12V + G12S and G12D + G12S) in both types of samples (2%, 2/106 and 10%, 2/20 in tissue and plasma samples, respectively). The median survival of patients with the G12D mutation in tissues was less than half that of other patients (median survival 101 days, 95% CI: 80-600 vs. 228 days, 95% CI: 184-602), with a statistically significant overall difference in survival (p = 0.0080, log-rank test), and furthermore it was less than that of all combined patients with other mutation types (101 days, 95% CI: 80-600 vs. 210 days, 95% CI: 161-602, p = 0.0166). For plasma samples, the survival of patients with this mutation was six times shorter than that of patients without the G12D mutation (27 days, 95% CI: 8-334 vs. 161 days, 95% CI: 107-536, p = 0.0200). In contrast, patients with detected KRAS G12R in the tissue survived nearly twice as long as other patients in the aggregate (286 days, 95% CI: 70-602 vs. 162 days, 95% CI: 122-600, p = 0.0374) or patients with other KRAS mutations (286 days, 95% CI: 70-602 vs. 137 days, 95% CI: 107-600, p = 0.0257). Conclusions: Differentiation of specific KRAS mutations in EUS-FNB and ctDNA (above all, the crucial G12D and G12R) is feasible in routine management of PDAC patients and imperative for assessment of prognosis.

Updates in Molecular Profiling of Pancreatic Ductal Adenocarcinoma

Outcomes from pancreatic ductal adenocarcinoma (PDAC) remain poor and better methods of prognostication and therapeutic approaches are needed. Recent advances in cancer genomics have led to the development of molecular subtypes of PDAC associated with clinical outcomes. Current evidence also suggests that the subtypes have differential response to first-line chemotherapy regimens. PDAC is also characterized by different stroma and immune environments. Further work is needed to confirm the utility of these subtypes to predicting response to different systemic therapies.

Natural TCRs targeting KRASG12V display fine specificity and sensitivity to human solid tumors

BACKGROUNDNeoantigens derived from KRASMUT have been described, but the fine antigen specificity of T cell responses directed against these epitopes is poorly understood. Here, we explore KRASMUT immunogenicity and the properties of 4 T cell receptors (TCRs) specific for KRASG12V restricted to the HLA-A3 superfamily of class I alleles.METHODSA phase 1 clinical vaccine trial targeting KRASMUT was conducted. TCRs targeting KRASG12V restricted to HLA-A*03:01 or HLA-A*11:01 were isolated from vaccinated patients or healthy individuals. A comprehensive analysis of TCR antigen specificity, affinity, crossreactivity, and CD8 coreceptor dependence was performed. TCR lytic activity was evaluated, and target antigen density was determined by quantitative immunopeptidomics.RESULTSVaccination against KRASMUT resulted in the priming of CD8+ and CD4+ T cell responses. KRASG12V -specific natural (not affinity enhanced) TCRs exhibited exquisite specificity to mutated protein with no discernible reactivity against KRASWT. TCR-recognition motifs were determined and used to identify and exclude crossreactivity to noncognate peptides derived from the human proteome. Both HLA-A*03:01 and HLA-A*11:01-restricted TCR-redirected CD8+ T cells exhibited potent lytic activity against KRASG12V cancers, while only HLA-A*11:01-restricted TCR-T CD4+ T cells exhibited antitumor effector functions consistent with partial coreceptor dependence. All KRASG12V-specific TCRs displayed high sensitivity for antigen as demonstrated by their ability to eliminate tumor cell lines expressing low levels of peptide/HLA (4.4 to 242) complexes per cell.CONCLUSIONThis study identifies KRASG12V-specific TCRs with high therapeutic potential for the development of TCR-T cell therapies.TRIAL REGISTRATIONClinicalTrials.gov NCT03592888.FUNDINGAACR SU2C/Lustgarten Foundation, Parker Institute for Cancer Immunotherapy, and NIH.

SHANK3 depletion leads to ERK signalling overdose and cell death in KRAS-mutant cancers

The KRAS oncogene drives many common and highly fatal malignancies. These include pancreatic, lung, and colorectal cancer, where various activating KRAS mutations have made the development of KRAS inhibitors difficult. Here we identify the scaffold protein SH3 and multiple ankyrin repeat domain 3 (SHANK3) as a RAS interactor that binds active KRAS, including mutant forms, competes with RAF and limits oncogenic KRAS downstream signalling, maintaining mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) activity at an optimal level. SHANK3 depletion breaches this threshold, triggering MAPK/ERK signalling hyperactivation and MAPK/ERK-dependent cell death in KRAS-mutant cancers. Targeting this vulnerability through RNA interference or nanobody-mediated disruption of the SHANK3-KRAS interaction constrains tumour growth in vivo in female mice. Thus, inhibition of SHANK3-KRAS interaction represents an alternative strategy for selective killing of KRAS-mutant cancer cells through excessive signalling.

KRAS G12C Inhibitors in the Treatment of Metastatic Colorectal Cancer

KRAS mutations contribute substantially to the overall colorectal cancer burden and have long been a focus of drug development efforts. After a lengthy preclinical road, KRAS inhibition via the G12C allele has finally become a therapeutic reality. Unlike in NSCLC, early studies of KRAS inhibitors in CRC struggled to demonstrate single agent activity. Investigation into these tissue-specific treatment differences has led to a deeper understanding of the complexities of MAPK signaling and the diverse adaptive feedback responses to KRAS inhibition. EGFR reactivation has emerged as a principal resistance mechanism to KRAS inhibitor monotherapy. Thus, the field has pivoted to dual EGFR/KRAS blockade with promising efficacy. Despite significant strides in the treatment of KRAS G12C mutated CRC, new challenges are on the horizon. Alternative RTK reactivation and countless acquired molecular resistance mechanisms have shifted the treatment goalpost. This review focuses on the historical and contemporary clinical strategies of targeting KRAS G12C alterations in CRC and highlights future directions to overcome treatment challenges.