Targeting Krasg12c -mutant cancer with a mutation-specific inhibitor

Quantitative Live Imaging Reveals Phase Dependency of PDAC Patient-Derived Organoids on ERK and AMPK Activity

Patient-derived organoids represent a novel platform to recapitulate the cancer cells in the patient tissue. While cancer heterogeneity has been extensively studied by a number of omics approaches, little is known about the spatiotemporal kinase activity dynamics. Here we applied a live imaging approach to organoids derived from 10 pancreatic ductal adenocarcinoma (PDAC) patients to comprehensively understand their heterogeneous growth potential and drug responses. By automated wide-area image acquisitions and analyses, the PDAC cells were non-selectively observed to evaluate their heterogeneous growth patterns. We monitored single-cell ERK and AMPK activities to relate cellular dynamics to molecular dynamics. Furthermore, we evaluated two anti-cancer drugs, a MEK inhibitor, PD0325901, and an autophagy inhibitor, hydroxychloroquine (HCQ), by our analysis platform. Our analyses revealed a phase-dependent regulation of PDAC organoid growth, where ERK activity is necessary for the early phase and AMPK activity is necessary for the late stage of organoid growth. Consistently, we found PD0325901 and HCQ target distinct organoid populations, revealing their combination is widely effective to the heterogeneous cancer cell population in a range of PDAC patient-derived organoid lines. Together, our live imaging quantitatively characterized the growth and drug sensitivity of human PDAC organoids at multiple levels: in single cells, single organoids, and individual patients. This study will pave the way for understanding the cancer heterogeneity and promote the development of new drugs that eradicate intractable cancer.

Validation of a targeted next-generation sequencing panel for pancreatic ductal adenocarcinomas

Pancreatic ductal adenocarcinoma (PDAC) is reported to be amongst the cancers with the lowest survival rate at 5 years. In the present study we aimed to validate a targeted next-generation sequencing (tNGS) panel to use in clinical routine, investigating genes important for PDAC diagnostic, prognostic and potential theragnostic aspect. In this NGS panel we also designed target regions to inquire about loss of heterozygosity (LOH) of chromosome 18 that has been described to be possibly linked to a worse disease progression. Copy number alteration has also been explored for a subset of genes. The last two methods are not commonly used for routine diagnostic with tNGS panels and we investigated their possible contribution to better characterize PDAC. A series of 140 formalin-fixed paraffin-embedded (FFPE) PDAC samples from 140 patients was characterized using this panel. Ninety-two % of patients showed alterations in at least one of the investigated genes (most frequent KRAS, TP53, SMAD4, CDKN2A and RNF43). Regarding LOH evaluation, we were able to detect chr18 LOH starting at 20% cell tumor percentage. The presence of LOH on chr18 is associated with a worse disease- and metastasis-free survival, in uni- and multivariate analyses. The present study validates the use of a tNGS panel for PDAC characterization, also evaluating chr18 LOH status for prognostic stratification.

Meeting report of the 5th European Biotransformation Workshop

Challenges, strategies and new technologies in the field of biotransformation were presented and discussed at the 5th European Biotransformation Workshop, which was held on March 14, 2024 on the Novartis Campus in Basel, Switzerland.In this meeting report we summarise the presentations and discussions from this workshop.The topics covered are listed below:Advances in understanding drug induced liver injury (DILI) risks of carboxylic acids and targeted covalent inhibitors.Biotransformation of oligonucleotide-based therapeutics including automated software tools for metabolite identification.Recent advances in metabolite synthesisQualification and validation of a new compact Low Energy Accelerator Mass Spectrometry (LEA) system for metabolite profiling.

Flavonoids as potential KRAS inhibitors: DFT, molecular docking, molecular dynamics simulation and ADMET analyses

KRAS mutations linked with cancer. Flavonoids were docked against KRAS G12C and G12D receptors. Abyssinone III, alpha naphthoflavone, beta naphthoflavone, abyssinone I, abyssinone II and beta naphthoflavone, genistin, daidzin showed good docking scores against KRAS G12C and G12D receptors, respectively. The MD simulation data revealed that Rg, RMSD, RMSF, and SASA values were within acceptable limits. Alpha and beta naphthoflavone showed good binding energies with KRAS G12C and G12D receptors. DFT and MEP analysis highlighted the nucleophilic and electrophilic zones of best-docked flavonoids. A novel avenue for the control of KRAS G12C and G12D mutations is made possible by flavonoids.

Targeting KRASG12C in Non-Small-Cell Lung Cancer: Current Standards and Developments

Among the most common molecular alterations detected in non-small-cell lung cancer (NSCLC) are mutations in Kristen Rat Sarcoma viral oncogene homolog (KRAS). KRAS mutant NSCLC is a heterogenous group of diseases, different from other oncogene-driven tumors in terms of biology and response to therapies. Despite efforts to develop drugs aimed at inhibiting KRAS or its signaling pathways, KRAS had remained undruggable for decades. The discovery of a small pocket in the binding switch II region of KRASG12C has revolutionized the treatment of KRASG12C-mutated NSCLC patients. Sotorasib and adagrasib, direct KRASG12C inhibitors, have been approved by the US Food and Drug Administration (FDA) and other regulatory agencies for patients with previously treated KRASG12C-mutated NSCLC, and these advances have become practice changing. However, first-line treatment in KRASG12C-mutated NSCLC does not differ from NSCLC without actionable driver genomic alterations. Treatment with KRASG12C inhibitors is not curative and patients develop progressive disease, so understanding associated mechanisms of drug resistance is key. New KRASG12C inhibitors and several combination therapy strategies, including with immune checkpoint inhibitors, are being studied in clinical trials. The aim of this review is to explore the clinical impact of KRAS, and outline different treatment approaches, focusing on the novel treatment of KRASG12C-mutated NSCLC.

Discovery of Covalent Lead Compounds Targeting 3CL Protease with a Lateral Interactions Spiking Neural Network

Covalent drugs exhibit advantages in that noncovalent drugs cannot match, and covalent docking is an important method for screening covalent lead compounds. However, it is difficult for covalent docking to screen covalent compounds on a large scale because covalent docking requires determination of the covalent reaction type of the compound. Here, we propose to use deep learning of a lateral interactions spiking neural network to construct a covalent lead compound screening model to quickly screen covalent lead compounds. We used the 3CL protease (3CL Pro) of SARS-CoV-2 as the screen target and constructed two classification models based on LISNN to predict the covalent binding and inhibitory activity of compounds. The two classification models were trained on the covalent complex data set targeting cysteine (Cys) and the compound inhibitory activity data set targeting 3CL Pro, respected, with good prediction accuracy (ACC > 0.9). We then screened the screening compound library with 6 covalent binding screening models and 12 inhibitory activity screening models. We tested the inhibitory activity of the 32 compounds, and the best compound inhibited SARS-CoV-2 3CL Pro with an IC50 value of 369.5 nM. Further assay implied that dithiothreitol can affect the inhibitory activity of the compound to 3CL Pro, indicating that the compound may covalently bind 3CL Pro. The selectivity test showed that the compound had good target selectivity to 3CL Pro over cathepsin L. These correlation assays can prove the rationality of the covalent lead compound screening model. Finally, covalent docking was performed to demonstrate the binding conformation of the compound with 3CL Pro. The source code can be obtained from the GitHub repository (https://github.com/guzh970630/Screen_Covalent_Compound_by_LISNN).

AXL signal mediates adaptive resistance to KRAS G12C inhibitors in KRAS G12C-mutant tumor cells

Recently, novel Kirsten rat sarcoma viral oncogene homolog (KRAS) inhibitors have been clinically developed to treat KRAS G12C-mutated non-small cell lung cancer (NSCLC) patients. However, achieving complete tumor remission is challenging. Therefore, the optimal combined therapeutic intervention with KRAS G12C inhibitors has a potentially crucial role in the clinical outcomes of patients. We investigated the underlying molecular mechanisms of adaptive resistance to KRAS G12C inhibitors in KRAS G12C-mutated NSCLC cells to devise a strategy preventing drug-tolerant cell emergence. We demonstrate that AXL signaling led to the adaptive resistance to KRAS G12C inhibitors in KRAS G12C-mutated NSCLC, activation of which is induced by GAS6 production via YAP. AXL inhibition reduced the viability of AXL-overexpressing KRAS G12C-mutated lung cancer cells by enhancing KRAS G12C inhibition-induced apoptosis. In xenograft models of AXL-overexpressing KRAS G12C-mutated lung cancer treated with KRAS G12C inhibitors, initial combination therapy with AXL inhibitor markedly delayed tumor regrowth compared with KRAS G12C inhibitor alone or with the combination after acquired resistance to KRAS G12C inhibitor. These results indicated pivotal roles for the YAP-GAS6-AXL axis and its inhibition in the intrinsic resistance to KRAS G12C inhibitor.

First Approval of Adagrasib for the Treatment of Non-Small Cell Lung Cancer Harboring a KRASG12C Mutation

Adagrasib is an orally bioavailable, highly selective, small-molecule, irreversible covalent inhibitor of KRAS^G12C. It was approved by the US FDA on December 12, 2022, for patients with tumors harboring the KRAS^G12C mutation in locally advanced or metastatic non-small cell lung cancer (NSCLC). Herein, synthesis, dosage and administration, mechanism of action, pharmacokinetics, pharmacodynamics, and adverse events of adagrasib are described.

C-terminus of PIEZO1 governs Ca2+ influx and intracellular ERK1/2 signaling pathway in mechanotransduction

Cells sense and respond to extracellular mechanical stress through mechanotransduction receptors and ion channels, which regulate cellular behaviors such as cell proliferation and differentiation. Among them, PIEZO1, piezo-type mechanosensitive ion channel component 1, has recently been highlighted as a mechanosensitive ion channel in various cell types including mesenchymal stem cells. We previously reported that PIEZO1 is essential for ERK1/2 phosphorylation and osteoblast differentiation in bone marrow-derived mesenchymal stem cells (BMSCs), induced by hydrostatic pressure loading and treatment with the PIEZO1-specific activator Yoda1. However, the molecular mechanism underlying how PIEZO1 induces mechanotransduction remains unclear. In this study, we investigated that the role of the C-terminus in regulating extracellular Ca2+ influx and activating the ERK1/2 signaling pathway. We observed the activation of Fluo-4 AM in the Yoda1-stimulated human BMSC line UE7T-13, but not in a calcium-depleted cell culture medium. Similarly, Western blotting analysis revealed that Yoda1 treatment induced ERK1/2 phosphorylation, but this induction was not observed in calcium-depleted cell culture medium. To investigate the functional role of the C-terminus of PIEZO1, we generated HEK293 cells stably expressing the full-length mouse PIEZO1 (PIEZO1-FL) and a deletion-type PIEZO1 lacking the C-terminal intracellular region containing the R-Ras-binding domain (PIEZO1-ΔR-Ras). We found that Yoda1 treatment predominantly activated Flou-4 AM and ERK1/2 in PIEZO1-FL-trasfected cells but neither in PIEZO1-ΔR-Ras-transfected cells nor control cells. Our results indicate that the C-terminus of PIEZO1, which contains the R-Ras binding domain, plays an essential role in Ca2+ influx and activation of the ERK1/2 signaling pathway, suggesting that this domain is crucial for the mechanotransduction of osteoblastic differentiation in BMSCs.

SLC25A21 downregulation promotes KRAS-mutant colorectal cancer progression by increasing glutamine anaplerosis

Emerging evidence shows that KRAS-mutant colorectal cancer (CRC) depends on glutamine (Gln) for survival and progression, indicating that targeting Gln metabolism may be a promising therapeutic strategy for KRAS-mutant CRC. However, the precise mechanism by which Gln metabolism reprogramming promotes and coordinates KRAS-mutant CRC progression remains to be fully investigated. Here, we discovered that solute carrier 25 member 21 (SLC25A21) expression was downregulated in KRAS-mutant CRC, and that SLC25A21 downregulation was correlated with poor survival of KRAS-mutant CRC patients. SLC25A21 depletion selectively accelerated the growth, invasion, migration, and metastasis of KRAS-mutant CRC cells in vitro and in vivo, and inhibited Gln-derived α-ketoglutarate (α-KG) efflux from mitochondria, thereby potentiating Gln replenishment, accompanied by increased GTP availability for persistent KRAS activation in KRAS-mutant CRC. The restoration of SLC25A21 expression impaired the KRAS-mutation-mediated resistance to cetuximab in KRAS-mutant CRC. Moreover, the arrested α-KG efflux that occurred in response to SLC25A21 depletion inhibited the activity of α-KG-dependent DNA demethylases, resulting in a further decrease in SLC25A21 expression. Our studies demonstrate that SLC25A21 plays a significant role as a tumor suppressor in KRAS-mutant CRC by antagonizing Gln-dependent anaplerosis to limit GTP availability for KRAS activation, which suggests potential alternative therapeutic strategies for KRAS-mutant CRC.

Targeting KRAS in Pancreatic Ductal Adenocarcinoma: The Long Road to Cure

Pancreatic ductal adenocarcinoma (PDAC) remains an important cause of cancer-related mortality, and it is expected to play an even bigger part in cancer burden in the years to come. Despite concerted efforts from scientists and physicians, patients have experienced little improvement in survival over the past decades, possibly because of the non-specific nature of the tested treatment modalities. Recently, the discovery of potentially targetable molecular alterations has paved the way for the personalized treatment of PDAC. Indeed, the central piece in the molecular framework of PDAC is starting to be unveiled. KRAS mutations are seen in 90% of PDACs, and multiple studies have demonstrated their pivotal role in pancreatic carcinogenesis. Recent investigations have shed light on the differences in prognosis as well as therapeutic implications of the different KRAS mutations and disentangled the relationship between KRAS and effectors of downstream and parallel signaling pathways. Additionally, the recognition of other mechanisms involving KRAS-mediated pathogenesis, such as KRAS dosing and allelic imbalance, has contributed to broadening the current knowledge regarding this molecular alteration. Finally, KRAS G12C inhibitors have been recently tested in patients with pancreatic cancer with relative success, and inhibitors of KRAS harboring other mutations are under clinical development. These drugs currently represent a true hope for a meaningful leap forward in this dreadful disease.

KRAS G12C in advanced NSCLC: Prevalence, co-mutations, and testing

KRAS is the most commonly mutated oncogene in advanced, non-squamous, non-small cell lung cancer (NSCLC) in Western countries. Of the various KRAS mutants, KRAS G12C is the most common variant (~40%), representing 10-13% of advanced non-squamous NSCLC. Recent regulatory approvals of the KRASG12C-selective inhibitors sotorasib and adagrasib for patients with advanced or metastatic NSCLC harboring KRASG12C have transformed KRAS into a druggable target. In this review, we explore the evolving role of KRAS from a prognostic to a predictive biomarker in advanced NSCLC, discussing KRAS G12C biology, real-world prevalence, clinical relevance of co-mutations, and approaches to molecular testing. Real-world evidence demonstrates significant geographic differences in KRAS G12C prevalence (8.9-19.5% in the US, 9.3-18.4% in Europe, 6.9-9.0% in Latin America, and 1.4-4.3% in Asia) in advanced NSCLC. Additionally, the body of clinical data pertaining to KRAS G12C co-mutations such as STK11, KEAP1, and TP53 is increasing. In real-world evidence, KRAS G12C-mutant NSCLC was associated with STK11, KEAP1, and TP53 co-mutations in 10.3-28.0%, 6.3-23.0%, and 17.8-50.0% of patients, respectively. Whilst sotorasib and adagrasib are currently approved for use in the second-line setting and beyond for patients with advanced/metastatic NSCLC, testing and reporting of the KRAS G12C variant should be included in routine biomarker testing prior to first-line therapy. KRAS G12C test results should be clearly documented in patients' health records for actionability at progression. Where available, next-generation sequencing is recommended to facilitate simultaneous testing of potentially actionable biomarkers in a single run to conserve tissue. Results from molecular testing should inform clinical decisions in treating patients with KRAS G12C-mutated advanced NSCLC.

Resistance to KRAS G12C Inhibition in Non-small Cell Lung Cancer

PURPOSE OF REVIEW

Although the recent development of direct KRASG12C inhibitors (G12Ci) has improved outcomes in KRAS mutant cancers, responses occur only in a fraction of patients, and among responders acquired resistance invariably develops over time. Therefore, the characterization of the determinants of acquired resistance is crucial to inform treatment strategies and to identify novel therapeutic vulnerabilities that can be exploited for drug development.

RECENT FINDINGS

Mechanisms of acquired resistance to G12Ci are heterogenous including both on-target and off-target resistance. On-target acquired resistance includes secondary codon 12 KRAS mutations, but also acquired codon 13 and codon 61 alterations, and mutations at drug binding sites. Off-target acquired resistance can derive from activating mutations in KRAS downstream pathway (e.g., MEK1), acquired oncogenic fusions (EML4-ALK, CCDC176-RET), gene level copy gain (e.g., MET amplification), or oncogenic alterations in other pro-proliferative and antiapoptotic pathways (e.g., FGFR3, PTEN, NRAS). In a fraction of patients, histologic transformation can also contribute to the development of acquire resistance. We provided a comprehensive overview of the mechanisms that limit the efficacy of this G12i and reviewed potential strategies to overcome and possibly delay the development of resistance in patients receiving KRAS directed targeted therapies.

Adagrasib in Advanced Solid Tumors Harboring a KRASG12C Mutation

PURPOSE

Adagrasib, a KRASG12C inhibitor, has demonstrated clinical activity in patients with KRASG12C-mutated non-small-cell lung cancer (NSCLC) and colorectal cancer (CRC). KRASG12C mutations occur rarely in other solid tumor types. We report evaluation of the clinical activity and safety of adagrasib in patients with other solid tumors harboring a KRASG12C mutation.

METHODS

In this phase II cohort of the KRYSTAL-1 study (ClinicalTrials.gov identifier: NCT03785249; phase Ib cohort), we evaluated adagrasib (600 mg orally twice daily) in patients with KRASG12C-mutated advanced solid tumors (excluding NSCLC and CRC). The primary end point was objective response rate. Secondary end points included duration of response, progression-free survival (PFS), overall survival, and safety.

RESULTS

As of October 1, 2022, 64 patients with KRASG12C-mutated solid tumors were enrolled and 63 patients treated (median follow-up, 16.8 months). The median number of prior lines of systemic therapy was 2. Among 57 patients with measurable disease at baseline, objective responses were observed in 20 (35.1%) patients (all partial responses), including 7/21 (33.3%) responses in pancreatic and 5/12 (41.7%) in biliary tract cancers. The median duration of response was 5.3 months (95% CI, 2.8 to 7.3) and median PFS was 7.4 months (95% CI, 5.3 to 8.6). Treatment-related adverse events (TRAEs) of any grade were observed in 96.8% of patients and grade 3-4 in 27.0%; there were no grade 5 TRAEs. TRAEs did not lead to treatment discontinuation in any patients.

CONCLUSION

Adagrasib demonstrates encouraging clinical activity and is well tolerated in this rare cohort of pretreated patients with KRASG12C-mutated solid tumors.

Establishing the Role of Iridoids as Potential Kirsten Rat Sarcoma Viral Oncogene Homolog G12C Inhibitors Using Molecular Docking; Molecular Docking Simulation; Molecular Mechanics Poisson-Boltzmann Surface Area; Frontier Molecular Orbital Theory; Molecular Electrostatic Potential; and Absorption, Distribution, Metabolism, Excretion, and Toxicity Analysis

The RAS gene family is one of the most frequently mutated oncogenes in human cancers. In KRAS, mutations of G12D and G12C are common. Here, 52 iridoids were selected and docked against 8AFB (KRAS G12C receptor) using Sotorasib as the standard. As per the docking interaction data, 6-O-trans-p-coumaroyl-8-O-acetylshanzhiside methyl ester (dock score: -9.9 kcal/mol), 6'-O-trans-para-coumaroyl geniposidic acid (dock score: -9.6 kcal/mol), 6-O-trans-cinnamoyl-secologanoside (dock score: -9.5 kcal/mol), Loganic acid 6'-O-beta-d-glucoside (dock score: -9.5 kcal/mol), 10-O-succinoylgeniposide (dock score: -9.4), Loganic acid (dock score: -9.4 kcal/mol), and Amphicoside (dock score: -9.2 kcal/mol) showed higher dock scores than standard Sotorasib (dock score: -9.1 kcal/mol). These common amino acid residues between iridoids and complexed ligands confirmed that all the iridoids perfectly docked within the receptor's active site. The 100 ns MD simulation data showed that RMSD, RMSF, radius of gyration, and SASA values were within range, with greater numbers of hydrogen bond donors and acceptors. MM/PBSA analysis showed maximum binding energy values of -7309 kJ/mol for 6-O-trans-p-coumaroyl-8-O-acetylshanzhiside methyl ester. FMO analysis showed that 6-O-trans-p-coumaroyl-8-O-acetylshanzhiside methyl ester was the most likely chemically reactive molecule. MEP analysis data highlighted the possible electrophilic and nucleophilic attack regions of the best-docked iridoids. Of all the best-docked iridoids, Loganic acid passed Lipinski, Pfizer, and GSK filters with a similar toxicity profile to Sotorasib. Thus, if we consider these iridoids to be KRAS G12C inhibitors, they will be a boon to mankind.

Computational study of novel natural inhibitors targeting Kirsten rat sarcoma viral oncogene homolog G12C

Lung adenocarcinoma is one of the most aggressive and rapidly fatal types of malignant lung tumor. Molecular docking and virtual screening were effectively and systematically used to identify specific targets in malignant tumors and screen potential drugs. Here, we screen perfect leading compounds from a medicate library (ZINC15 database) and analyze their properties (conveyance, absorption, metabolism, excretion, and harmless forecasts) with potential inhibition of Kirsten Rat Sarcoma Viral Oncogene Homolog (KRAS) G12C. Further results demonstrated that ZINC000013817014 and ZINC000004098458 were screened out from the ZINC15 database and were identified to have a much better binding affinity and more favorable interaction vitality binding with KRAS G12C and less rat carcinogenicity, Ames mutagenicity, way better dissolvability in water and noninhibition with cytochrome P-450 2D6. Molecular dynamics simulation analysis indicated that the binding capacity of these two compounds and KRAS G12C, ZINC000013817014-KRAS G12C, and ZINC000004098458-KRAS G12C is stable in the natural environment. Our findings reveal that ZINC000013817014 and ZINC000004098458 were perfect leading compounds to be inhibitors binding with KRAS G12C, which were selected as safe drug candidates and a cornerstone for KRAS G12C-related medicine plan and improvement. What is more, we have conducted a Cell Counting Kit-8 to verify the exactly inhibitory effects of the two selected drugs on Lung adenocarcinoma. This study establishes a solid framework for systematic anticancer medication research and development.

Real-world outcomes in patients with KRAS G12C-mutated advanced non-small cell lung cancer treated with docetaxel in second-line or beyond

INTRODUCTION

The KRAS G12C mutation has recently become a druggable target in non-small cell lung cancer (NSCLC). In this observational study, we present real-world clinicopathological characteristics, treatment patterns, and survival outcomes data in patients with KRAS mutation-positive advanced NSCLC (aNSCLC), including those with KRAS G12C and KRAS non-G12C mutations, who received docetaxel as standard-of-care treatment in the second-line and beyond (2L+).

METHODS

US-based electronic health record-derived de-identified databases were used to assess clinicopathological characteristics and outcomes in adult aNSCLC patients with KRAS mutations treated with 2L+ docetaxel between January 1, 2011, and March 31, 2021. The primary endpoints were median real-world overall survival OS (rwOS) and median real-world progression-free survival (rwPFS), which were estimated in 2L, third-line, fourth-line, and 2L+ analysis sets among patients who had a 6-month minimum opportunity for follow-up and were not taking a clinical trial drug.

RESULTS

Of the 677 patients with KRAS-mutant aNSCLC (KRAS mutant cohort) treated with 2L+ docetaxel, 295 (43.6%) had KRAS G12C mutation (KRAS G12C cohort) and 382 (56.4%) had KRAS non-G12C mutation (KRAS non-G12C cohort). Across all cohorts, approximately 47%, 35%, 14-15%, and 6-9% of patients received 2L, third-line, fourth-line, and fifth- or later-line docetaxel, respectively. In the KRAS G12C cohort, ∼68% of patients were treated with a PD-1/PD-L1 inhibitor prior to 2L+ docetaxel. Most 2L+ docetaxel regimens in the KRAS G12C cohort were combinations (59.5%), primarily with ramucirumab (45.2%). In the KRAS G12C cohort, the median rwOS and median rwPFS after 2L+ docetaxel were 6.0 (95% CI, 4.9-7.1) and 3.4 (95% CI, 2.7-4.2) months, respectively, with similar trends observed in other cohorts and lines of therapy.

CONCLUSIONS

Real-world outcomes were poor in patients with KRAS G12C-mutated aNSCLC treated with 2L+ docetaxel. Targeted and more efficacious treatment options in these patients are warranted.

New Approved Drugs Appearing in the Pharmaceutical Market in 2022 Featuring Fragments of Tailor-Made Amino Acids and Fluorine

The strategic fluorination of oxidatively vulnerable sites in bioactive compounds is a relatively recent, widely used approach allowing us to modulate the stability, bio-absorption, and overall efficiency of pharmaceutical drugs. On the other hand, natural and tailor-made amino acids are traditionally used as basic scaffolds for the development of bioactive molecules. The main goal of this review article is to emphasize these general trends featured in recently approved pharmaceutical drugs.

The Therapeutic Landscape for KRAS-Mutated Colorectal Cancers

Colorectal cancer is one of the world's most prevalent and lethal cancers. Mutations of the KRAS gene occur in ~40% of metastatic colorectal cancers. While this cohort has historically been difficult to manage, the last few years have shown exponential growth in the development of selective inhibitors targeting KRAS mutations. Their foremost mechanism of action utilizes the Switch II binding pocket and Cys12 residue of GDP-bound KRAS proteins in G12C mutants, confining them to their inactive state. Sotorasib and Adagrasib, both FDA-approved for the treatment of non-small cell lung cancer (NSCLC), have been pivotal in paving the way for KRAS G12C inhibitors in the clinical setting. Other KRAS inhibitors in development include a multi-targeting KRAS-mutant drug and a G12D mutant drug. Treatment resistance remains an issue with combination treatment regimens including indirect pathway inhibition and immunotherapy providing possible ways to combat this. While KRAS-mutant selective therapy has come a long way, more work is required to make this an effective and viable option for patients with colorectal cancer.

Recent progress in targeting KRAS mutant cancers with covalent G12C-specific inhibitors

KRAS^G12C has been identified as a potential target in the treatment of solid tumors. One of the most often transformed proteins in human cancers is the small Kirsten rat sarcoma homolog (KRAS) subunit of GTPase, which is typically the oncogene driver. KRAS^G12C is altered to keep the protein in an active GTP-binding form. KRAS has long been considered an 'undrugable' target, but sustained research efforts focusing on the KRAS^G12C mutant cysteine have achieved promising results. For example, the US Food and Drug Administration (FDA) has passed emergency approval for sotorasib and adagrasib for the treatment of metastatic lung cancer. Such achievements have sparked several original approaches to KRAS^G12C. In this review, we focus on the design, development, and history of KRAS^G12C inhibitors.

KRAS G12C mutated advanced non-small cell lung cancer (NSCLC): Characteristics, treatment patterns and overall survival from a Danish nationwide observational register study

OBJECTIVES

We aimed to characterize the advanced NSCLC population in terms of KRAS G12C prevalence, patient characteristics, and survival outcomes after the introduction of immunotherapies.

MATERIALS AND METHODS

We identified adult patients diagnosed with advanced NSCLC between January 1, 2018 and June 30, 2021 using the Danish health registries. Patients were grouped by mutational status (any KRAS mutation, KRAS G12C, and KRAS/EGFR/ALK wildtype [Triple WT]). We analyzed KRAS G12C prevalence, patient and tumor characteristics, treatment history, time-to-next-treatment (TTNT), and overall survival (OS).

RESULTS

We identified 7,440 patients of whom 40% (n = 2,969) were KRAS tested prior to the first line of therapy (LOT1). Among the KRAS tested, 11% (n = 328) harbored KRAS G12C. More KRAS G12C patients were women (67%), smokers (86%), had a high (≥50%) level of PD-L1 expression (54%), and more frequently received anti-PD-L1 treatment than any other group. From the date of the mutational test result, OS (7.1-7.3 months) was similar between the groups. OS from LOT1 (14.0 months) and LOT2 (10.8 months), and TTNT from LOT1 (6.9 months) and LOT2 (6.3 months) was numerically longer for the KRAS G12C mutated group compared to any other group. However, from LOT1 and LOT2, the OS and TTNT were comparable when stratifying the groups by PD-L1 expression level. Regardless of the mutational group, OS was markedly longer for patients with high PD-L1 expression.

CONCLUSION

In patients diagnosed with advanced NSCLC after the implementation of anti-PD-1/L1 therapies, the survival in KRAS G12C mutated patients is comparable to patients with any KRAS mutation, Triple WT, and all NSCLC patients.

Ras superfamily GTPase activating proteins in cancer: Potential therapeutic targets?

To search more therapeutic strategies for Ras-mutant tumors, regulators of the Ras superfamily involved in the GTP/GDP (guanosine triphosphate/guanosine diphosphate) cycle have been well concerned for their anti-tumor potentials. GTPase activating proteins (GAPs) provide the catalytic group necessary for the hydrolysis of GTPs, which accelerate the switch by cycling between GTP-bound active and GDP-bound inactive forms. Inactivated GAPs lose their function in activating GTPase, leading to the continuous activation of downstream signaling pathways, uncontrolled cell proliferation, and eventually carcinogenesis. A growing number of evidence has shown the close link between GAPs and human tumors, and as a result, GAPs are believed as potential anti-tumor targets. The present review mainly summarizes the critically important role of GAPs in human tumors by introducing the classification, function and regulatory mechanism. Moreover, we comprehensively describe the relationship between dysregulated GAPs and the certain type of tumor. Finally, the current status, research progress, and clinical value of GAPs as therapeutic targets are also discussed, as well as the challenges and future direction in the cancer therapy.

ZNF24 regulates the progression of KRAS mutant lung adenocarcinoma by promoting SLC7A5 translation

Background

Clinical treatment of RAS mutant cancers is challenging because of the complexity of the Ras signaling pathway. SLC7A5 is a newly discovered downstream gene of the Ras signaling pathway, but the regulatory mechanism is unclear. We aimed to explore the molecular mechanism and role in KRAS mutant lung adenocarcinoma progression.

Methods

Key gene that regulated SLC7A5 in KRAS mutant lung adenocarcinoma was screened by RNA sequencing and bioinformatics analysis. The effect of this gene on the expression of SLC7A5 was studied by RNAi. The regulatory mechanism between the two genes was investigated by immunofluorescence, CoIP, pulldown and yeast two-hybrid assays. The location of the two genes was determined by inhibiting Ras and the downstream pathways PI3K-AKT and MEK-ERK. By in vivo and in vitro experiments, the effects of the key gene on the biological functions of KRAS mutant lung adenocarcinoma were explored.

Results

We found a novel gene, ZNF24, which upregulated SLC7A5 protein expression rather than mRNA expression in KRAS mutant lung adenocarcinoma. Endogenous protein interactions occurred between ZNF24 and SLC7A5. Ras inhibition reduced the expression of ZNF24 and SLC7A5. ZNF24 and SLC7A5 are located downstream of the MEK-ERK and PI3K-AKT pathways. In vivo and in vitro functional experiments confirmed that the ZNF24-SLC7A5 signaling axis promoted the proliferation, invasion and migration of KRAS mutant lung adenocarcinoma.

Conclusions

ZNF24 promoted the growth of KRAS mutant lung adenocarcinoma by upregulating SLC7A5 protein expression, which suggested that ZNF24 is a new biomarker of KRAS mutant tumors and could be a new potential therapeutic target for Ras-driven tumors.

Inhibition of colon cancer K-RasG13D mutation reduces cancer cell proliferation but promotes stemness and inflammation via RAS/ERK pathway

K-Ras is a well-studied oncogene, and its mutation is frequently found in epithelial cancers like pancreas, lung, and colorectal cancers. Cancer cells harboring K-Ras mutations are difficult to treat due to the drug resistance and metastasis properties. Cancer stem cells (CSCs) are believed the major cause of chemotherapeutic resistance and responsible for tumor recurrence and metastasis. But how K-Ras mutation affects CSCs and inflammation is not clear. Here, we compared two colon cancer cell lines, HCT-116 and HT-29, with the former being K-Ras^G13D mutant and the latter being wildtype. We found that HCT-116 cells treated with a K-Ras mutation inhibitor S7333 formed significantly more tumor spheroids than the untreated control, while the wild type of HT-29 cells remained unchanged. However, the size of tumor spheroids was smaller than the untreated controls, indicating their proliferation was suppressed after S7333 treatment. Consistent with this, the expressions of stem genes Lgr5 and CD133 significantly increased and the expression of self-renewal gene TGF-β1 also increased. The flow cytometry analysis indicated that the expression of stem surface marker CD133 increased in the treated HCT-116 cells. To understand the pathway through which the G13D mutation induced the effects, we studied both RAS/ERK and PI3K/Akt pathways using specific inhibitors SCH772984 and BEZ235. The results indicated that RAS/ERK rather than PI3K/Akt pathway was involved. As CSCs play the initial role in cancer development and the inflammation is a vital step during tumor initiation, we analyzed the correlation between increased stemness and inflammation. We found a close correlation of increased Lgr5 and CD133 with proinflammatory factors like IL-17, IL-22, and IL-23. Together, our findings suggest that K-Ras^G13D mutation promotes cancer cell growth but decreases cancer stemness and inflammation thus tumorigenesis and metastasis potential in colon cancer. Inhibition of this mutation reverses the process. Therefore, care needs be taken when employing targeted therapies to K-Ras^G13D mutations in clinics.

Discovery of novel Quinazoline-based KRAS G12C inhibitors as potential anticancer agents

A series of novel quinazoline analogs were designed and synthesized based on ARS-1620 and LLK-10 (a KRAS inhibitor reported by us recently) as KRAS G12C inhibitors with a 5-nitrofuran-2-carboxylic acid warhead. Most of the newly synthesized compounds exhibited antiproliferative activities similar to or better than ARS-1620 and LLK-10. Among them, compound KS-19 showed the highest activity (IC50 = 460 ∼ 870 nM) and reasonable selectivity (3 to 27-fold) for inhibiting the proliferation of KRAS G12C-mutated cells (NCI-H358 and NCI-H23) over other KRAS mutant (e.g. G13D, G12D, G12S, G12V, WT) cancer cells. ITC, KRAS-GTP pull-down assay and western blot analysis demonstrated that KS-19 could bind to KRAS G12C protein with high affinity (KD = 97 nM), thus decreasing the active form of KRAS G12C (KRAS G12C-GTP) and phosphorylated Erk, and leading to NCI-H358 tumor cell apoptosis. In addition, KS-19 was able to suppress the formation of NCI-H358 and NCI-H23 tumor colonies in a dose-dependent manner. Moreover, in vivo efficacy studies indicated that KS-19 (40 mg/kg) was effective in suppressing tumor growth in nude mice bearing NCI-H358 tumor xenografts with a TGI (tumor growth inhibition) of 47 %, comparable to that of ARS-1620 (50 %). Lastly, KS-19 possessed a benign toxicity profile without causing bone marrow suppression and any obvious morphological abnormalities in major organs of mice. Collectively, these results suggest that KS-19 represents a novel inhibitor of KRAS G12C worthy of further investigation as a potential anticancer agent.

Adagrasib, a KRAS G12C inhibitor, reverses the multidrug resistance mediated by ABCB1 in vitro and in vivo

Background

Multidrug resistance (MDR) is a complex phenomenon that frequently leads to chemotherapy failure during cancer treatment. The overexpression of ATP-binding cassette (ABC) transporters represents the major mechanism contributing to MDR. To date, no effective MDR modulator has been applied in clinic. Adagrasib (MRTX849), a specific inhibitor targeting KRAS G12C mutant, is currently under investigation in clinical trials for the treatment of non-small cell lung cancer (NSCLC). This study focused on investigating the circumvention of MDR by MRTX849.

Methods

The cytotoxicity and MDR reversal effect of MRTX849 were assessed by MTT assay. Drug accumulation and drug efflux were evaluated by flow cytometry. The MDR reversal by MRTX849 in vivo was investigated in two ABCB1-overexpressing tumor xenograft models in nude mice. The interaction between MRTX849 and ABCB1 substrate binding sites was studied by the [125I]-IAAP-photoaffinity labeling assay. The vanadate-sensitive ATPase assay was performed to identify whether MRTX849 would change ABCB1 ATPase activity. The effect of MRTX849 on expression of ABCB1 and PI3K/AKT signaling molecules was examined by flow cytometry, Western blot and Quantitative Real-time PCR analyses.

Results

MRTX849 was shown to enhance the anticancer efficacy of ABCB1 substrate drugs in the transporter-overexpressing cells both in vitro and in vivo. The MDR reversal effect was specific against ABCB1 because no similar effect was observed in the parental sensitive cells or in ABCG2-mediated MDR cells. Mechanistically, MRTX849 increased the cellular accumulation of ABCB1 substrates including doxorubicin (Dox) and rhodamine 123 (Rho123) in ABCB1-overexpressing MDR cells by suppressing ABCB1 efflux activity. Additionally, MRTX849 stimulated ABCB1 ATPase activity and competed with [125I]-IAAP for photolabeling of ABCB1 in a concentration-dependent manner. However, MRTX849 did not alter ABCB1 expression or phosphorylation of AKT/ERK at the effective MDR reversal drug concentrations.

Conclusions

In summary, MRTX849 was found to overcome ABCB1-mediated MDR both in vitro and in vivo by specifically attenuating ABCB1 efflux activity in drug-resistant cancer cells. Further studies are warranted to translate the combination of MRTX849 and conventional chemotherapy to clinical application for circumvention of MDR.

Efficient Correction of Oncogenic KRAS and TP53 Mutations through CRISPR Base Editing

KRAS is the most frequently mutated oncogene in human cancer, and its activating mutations represent long-sought therapeutic targets. Programmable nucleases, particularly the CRISPR-Cas9 system, provide an attractive tool for genetically targeting KRAS mutations in cancer cells. Here, we show that cleavage of a panel of KRAS driver mutations suppresses growth in various human cancer cell lines, revealing their dependence on mutant KRAS. However, analysis of the remaining cell population after long-term Cas9 expression unmasked the occurence of oncogenic KRAS escape variants that were resistant to Cas9-cleavage. In contrast, the use of an adenine base editor to correct oncogenic KRAS mutations progressively depleted the targeted cells without the appearance of escape variants and allowed efficient and simultaneous correction of a cancer-associated TP53 mutation. Oncogenic KRAS and TP53 base editing was possible in patient-derived cancer organoids, suggesting that base editor approaches to correct oncogenic mutations could be developed for functional interrogation of vulnerabilities in a personalized manner for future precision oncology applications.

SIGNIFICANCE

Repairing KRAS mutations with base editors can be used for providing a better understanding of RAS biology and may lay the foundation for improved treatments for KRAS-mutant cancers.

Activity of Adagrasib (MRTX849) in Brain Metastases: Preclinical Models and Clinical Data from Patients with KRASG12C-Mutant Non-Small Cell Lung Cancer

PURPOSE

Patients with KRAS-mutant non-small cell lung cancer (NSCLC) with brain metastases (BM) have a poor prognosis. Adagrasib (MRTX849), a potent oral small-molecule KRASG12C inhibitor, irreversibly and selectively binds KRASG12C, locking it in its inactive state. Adagrasib has been optimized for favorable pharmacokinetic properties, including long half-life (∼24 hours), extensive tissue distribution, dose-dependent pharmacokinetics, and central nervous system penetration; however, BM-specific antitumor activity of KRASG12C inhibitors remains to be fully characterized.

EXPERIMENTAL DESIGN

A retrospective database query identified patients with KRAS-mutant NSCLC to understand their propensity to develop BM. Preclinical studies assessed physiochemical and pharmacokinetic properties of adagrasib. Mice bearing intracranial KRASG12C-mutant NSCLC xenografts (LU99-Luc/H23-Luc/LU65-Luc) were treated with clinically relevant adagrasib doses, and levels of adagrasib in plasma, cerebrospinal fluid (CSF), and brain were determined along with antitumor activity. Preliminary clinical data were collected from 2 patients with NSCLC with untreated BM who had received adagrasib 600 mg twice daily in the phase Ib cohort of the KRYSTAL-1 trial; CSF was collected, adagrasib concentrations measured, and antitumor activity in BM evaluated.

RESULTS

Patients with KRAS-mutant NSCLC demonstrated high propensity to develop BM (≥40%). Adagrasib penetrated into CSF and demonstrated tumor regression and extended survival in multiple preclinical BM models. In 2 patients with NSCLC and untreated BM, CSF concentrations of adagrasib measured above the target cellular IC50. Both patients demonstrated corresponding BM regression, supporting potential clinical activity of adagrasib in the brain.

CONCLUSIONS

These data support further development of adagrasib in patients with KRASG12C-mutant NSCLC with untreated BM. See related commentary by Kommalapati and Mansfield, p. 3179.

Thermal Shift Assay for Small GTPase Stability Screening: Evaluation and Suitability

Thermal unfolding methods are commonly used as a predictive technique by tracking the protein's physical properties. Inherent protein thermal stability and unfolding profiles of biotherapeutics can help to screen or study potential drugs and to find stabilizing or destabilizing conditions. Differential scanning calorimetry (DSC) is a 'Gold Standard' for thermal stability assays (TSA), but there are also a multitude of other methodologies, such as differential scanning fluorimetry (DSF). The use of an external probe increases the assay throughput, making it more suitable for screening studies, but the current methodologies suffer from relatively low sensitivity. While DSF is an effective tool for screening, interpretation and comparison of the results is often complicated. To overcome these challenges, we compared three thermal stability probes in small GTPase stability studies: SYPRO Orange, 8-anilino-1-naphthalenesulfonic acid (ANS), and the Protein-Probe. We studied mainly KRAS, as a proof of principle to obtain biochemical knowledge through TSA profiles. We showed that the Protein-Probe can work at lower concentration than the other dyes, and its sensitivity enables effective studies with non-covalent and covalent drugs at the nanomolar level. Using examples, we describe the parameters, which must be taken into account when characterizing the effect of drug candidates, of both small molecules and Designed Ankyrin Repeat Proteins.

The treatment of advanced non-small cell lung cancer harboring KRAS mutation: a new class of drugs for an old target-a narrative review

Background and Objective

The genetic nature of cancer provides the rationale to support the need for molecular diagnosis and patient selection for individualised antineoplastic treatments that are the best in both tolerability and efficacy for each cancer patient, including non-small cell lung cancer (NSCLC) patients. Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations represent the prevalent oncogenic driver in NSCLC, being detected in roughly one-third of cases and KRAS G12C is the most frequent mutation found in approximately 13% of patients.

Methods

This paper gives an overview of the numerous scientific efforts in recent decades aimed at KRAS inhibition.

Key Content and Findings

Sotorasib is the first approved KRAS G12C inhibitor that has been shown to provide a durable clinical benefit in patients with pre-treated NSCLC with KRAS G12C mutation. Together with the development of new targeted drugs, the development of strategies to control resistance mechanisms is one of the major drivers of research that is exploring the use of KRAS inhibitors not only alone, but also in combination with other targeted therapies, chemotherapy and immunotherapy.

Conclusions

This review will describe the major therapeutic developments in KRAS mutation-dependent NSCLC and will analyse future perspectives to maximise benefits for this group of patients.

Coexistence of two missense mutations in the KRAS gene in adenocarcinoma of the lung: a possible indicator of poor prognosis

Background

KRAS mutations are present in up to 30% of patients with lung adenocarcinoma. The two most common KRAS mutations in non-small cell lung cancer (NSCLC) are G12C (~40%) and G12V (~22%). We describe the case of a 63-year-old Asian male patient with a very aggressive lung adenocarcinoma harbouring two coexisting missense mutations in the same exon.

Methods

The patient presented with a 6 cm spiculated lung mass and bilateral mediastinal lymphadenopathy on imaging. A cytology sample was obtained from EBUS-TBNA of mediastinal lymph nodes, and mutation screening was performed by next-generation sequencing using the Ion Torrent Cancer Hotspot panel.

Results

Cytological examination and immunocytochemistry confirmed the presence of metastatic lung adenocarcinoma. The molecular analysis revealed the coexistence of two missense mutations: c.34G > T; p.(Gly12Cys) and c.38G > T; A; p.(Gly13Asp) in exon 2 of the KRAS gene. The two independent variants were confirmed on Integrative Genomic Viewer (IGV), suggesting molecularly independent clones. The patient was treated with palliative care and died within two months of the diagnosis.

Conclusions

The present case showed aggressive clinical behaviour. It is questionable whether this aggressive course was due to the coexistence of multiple mutations or to a specific single mutation. Data in the literature regarding the outcome of polyclonal KRAS polyclonal lung adenocarcinomas are scarce, but some evidence seems to indicate that specific mutations may have prognostic value, possibly depending on the disease setting.

Response to immunotherapy in KRAS G12C mutated NSCLC: a single-centre retrospective observational study

Background: Non-small cell lung cancer is the leading cause of cancer death worldwide. New strategies in molecular therapies are being explored to detect and target genetic mutations in NSCLC. Therefore, it is also important to understand the interaction between these mutations and other therapies. This study focuses on possible correlations between the KRAS-G12C mutation and response of patients treated with immunotherapy.

Methods: Twenty-two patients with stage IV NSCLC undergoing immunotherapy were divided into two groups treated with first- and second-line therapy, respectively. KRAS-G12C mutation was detected by liquid biopsy Idylla KRAS assay.

Results: In first-line treated patients, there was no significant increase in PFS in patients with the KRAS mutation (20 months versus 14.5 months, HR = 1.31; CI 95% = 0.25–6.71; p value = 0.76) and no difference in OS (OS = 21 months, HR = 1; CI 95% = 0.17–6.2; p value > 0.99). In the second group, KRAS G12C mutated patients had a median PFS of 23 months compared with a median PFS of only 5 months among nonmutated patients (HR = 3.28; CI 95% = 0.86–12.5; p value = 0.03).

Conclusion: The results of this study do not reveal a clear correlation between mutation and response to immunotherapy. The mechanism regulating immune system activity in the tumor microenvironment remains unclear.

Virtual Screening Based on Machine Learning Explores Mangrove Natural Products as KRASG12C Inhibitors

Mangrove secondary metabolites have many unique biological activities. We identified lead compounds among them that might target KRAS^G12C. KRAS is considered to be closely related to various cancers. A variety of novel small molecules that directly target KRAS are being developed, including covalent allosteric inhibitors for KRAS^G12C mutant, protein–protein interaction inhibitors that bind in the switch I/II pocket or the A59 site, and GTP-competitive inhibitors targeting the nucleotide-binding site. To identify a candidate pool of mangrove secondary metabolic natural products, we tested various machine learning algorithms and selected random forest as a model for predicting the targeting activity of compounds. Lead compounds were then subjected to virtual screening and covalent docking, integrated absorption, distribution, metabolism and excretion (ADME) testing, and structure-based pharmacophore model validation to select the most suitable compounds. Finally, we performed molecular dynamics simulations to verify the binding mode of the lead compound to KRAS^G12C. The lazypredict function package was initially used, and the Accuracy score and F1 score of the random forest algorithm exceeded 60%, which can be considered to carry a strong ability to distinguish the data. Four marine natural products were obtained through machine learning identification and covalent docking screening. Compound 44 and compound 14 were selected for further validation after ADME and toxicity studies, and pharmacophore analysis indicated that they had a favorable pharmacodynamic profile. Comparison with the positive control showed that they stabilized switch I and switch II, and like MRTX849, retained a novel binding mechanism at the molecular level. Molecular dynamics analysis showed that they maintained a stable conformation with the target protein, so compound 44 and compound 14 may be effective inhibitors of the G12C mutant. These findings reveal that the mangrove-derived secondary metabolite compound 44 and compound 14 might be potential therapeutic agents for KRAS^G12C.

Concurrent RAS and RAS/BRAF V600E Variants in Colorectal Cancer: More Frequent Than Expected? A Case Report

The assessment of RAS and BRAF mutational status is one of the main steps in the diagnostic and therapeutic algorithm of metastatic colorectal cancer (mCRC). Multiple mutations in the BRAF and RAS pathway are described as a rare event, with concurrent variants in KRAS and BRAF genes observed in approximately 0.05% of mCRC cases. Here, we report data from a case series affected by high-risk stage III and stage IV CRC and tested for RAS and BRAF mutation, treated at our Medical Oncology Unit. The analysis of KRAS, NRAS (codons 12, 13, 59, 61, 117, 146), and BRAF (codon 600) hotspot variants was performed in 161 CRC tumors from August 2018 to September 2021 and revealed three (1.8%) patients showing mutations in both KRAS and BRAF (V600E), including two cases with earlier CRC and one with metastatic disease. We also identified one patient (0.6%) with a mutation in both KRAS and NRAS genes and another one (0.6%) with a double KRAS mutation. Notably, the latter was characterized by aggressive behavior and poor clinical outcome. The mutational status, pathological features, and clinical history of these five CRC cases are described. Overall, this study case series adds evidence to the limited available literature concerning both the epidemiological and clinical aspects of CRC cases characterized by the presence of concurrent RAS/BRAF variants. Future multicentric studies will be required to increase the sample size and provide additional value to results observed so far in order to improve clinical management of this subgroup of CRC patients.

First-in-Human Phase I/IB Dose-Finding Study of Adagrasib (MRTX849) in Patients With Advanced KRASG12C Solid Tumors (KRYSTAL-1)

Adagrasib (MRTX849) is an oral, highly selective, small-molecule, covalent inhibitor of KRAS^G12C. We report results from a phase I/IB study of adagrasib in non–small-cell lung cancer, colorectal cancer, and other solid tumors harboring the KRAS^G12C mutation.

The path to the clinic: a comprehensive review on direct KRASG12C inhibitors

The RAS oncogene is both the most frequently mutated oncogene in human cancer and the first confirmed human oncogene to be discovered in 1982. After decades of research, in 2013, the Shokat lab achieved a seminal breakthrough by showing that the activated KRAS isozyme caused by the G12C mutation in the KRAS gene can be directly inhibited via a newly unearthed switch II pocket. Building upon this groundbreaking discovery, sotorasib (AMG510) obtained approval by the United States Food and Drug Administration in 2021 to become the first therapy to directly target the KRAS oncoprotein in any KRAS-mutant cancers, particularly those harboring the KRASG12C mutation. Adagrasib (MRTX849) and other direct KRASG12C inhibitors are currently being investigated in multiple clinical trials. In this review, we delve into the path leading to the development of this novel KRAS inhibitor, starting with the discovery, structure, and function of the RAS family of oncoproteins. We then examine the clinical relevance of KRAS, especially the KRASG12C mutation in human cancer, by providing an in-depth analysis of its cancer epidemiology. Finally, we review the preclinical evidence that supported the initial development of the direct KRASG12C inhibitors and summarize the ongoing clinical trials of all direct KRASG12C inhibitors.

Molecular Signatures of KRAS-Mutated Lung Adenocarcinoma: Analysis of Concomitant EGFR, ALK, STK11, and PD-L1 Status

Background

KRAS mutations are the most common oncogenic driver mutations of non-small cell lung cancer (NSCLC) in the Western world. Mutations of the KRAS gene are most prevalent in the patient population of current and former cigarette smokers. With the recent pivotal approval of a targeted inhibitor therapy for patients with KRAS p.G12C mutated and pretreated NSCLC, analysis of the heterogeneity of KRAS mutations and concomitant molecular alterations in patients with these tumors at all clinical stages is indicated.

Methods

In this retrospective analysis, patient pathology records were reviewed for all cases receiving a pathologic diagnosis of NSCLC within our hospital system. All data were collected with IRB approval. Cases of indeterminate tumor type favoring a non-lung primary, as well as non-adenocarcinoma NSCLC (eg, squamous) were excluded from the cohort. In this hospital system, molecular testing for KRAS mutations is part of a molecular biomarker panel that is reflex ordered at initial diagnosis by the pathologist and may be performed as a single gene test or as a solid organ cancer hotspot panel by next generation sequencing. For each patient, KRAS mutational status and specific KRAS mutations, if present, were collated. Additional information assessed for this study included patient demographics (age, gender, and smoking history), tumor staging if available, PD-L1 expression levels by immunohistochemistry (IHC), and the presence of other genetic alterations (EGFR, ALK, and STK11).

Results

Between January 1, 2017 and January 1, 2019, there were 276 patients diagnosed with NSCLC of all stages who had KRAS mutational analysis performed in our hospital system and who met the criteria for inclusion into the study cohort. A KRAS driver mutation was detected in 29% of these patients. The most frequently identified KRAS mutation was p.G12C (38%), followed by p.G12D (21%) and p.G12V (13%). KRAS-mutated lung adenocarcinoma was significantly associated with current or former patient smoking status in this cohort (29/202 (14%) smokers and 1/74 (1%) non-smokers; P = .0006). PD-L1 expression of at least 1% by IHC was present in 43% of KRAS-mutated lung adenocarcinomas and 45% of non-KRAS-mutated adenocarcinomas. In this study, KRAS mutations were not found to co-occur with gene alterations in EGFR, ALK, or STK11. In 48% of cases, at least one genetic alteration (KRAS, ALK, EGFR, or STK11) was identified.

Conclusions

In this study cohort, KRAS-mutated lung adenocarcinoma demonstrated significant mutational heterogeneity, which is consistent with previously published studies. KRAS mutational status was also significantly associated with a current or former smoking history. Notably, p.G12C was the most frequently identified KRAS mutation in this cohort, with a frequency of 38%. This finding is particularly relevant given the recent approval of a KRAS p.G12C-specific targeted inhibitor therapy and the continued development of additional KRAS targeted therapies that may prove effective in treating NSCLC. These findings also highlight the necessity of considering molecular testing for KRAS mutations in patients with NSCLC and a smoking history, as this population most frequently harbors KRAS mutations and may benefit from these emerging targeted therapies.

Cytotoxicity of combinations of the pan-KRAS inhibitor BAY-293 against primary non-small lung cancer cells

KRAS is mutated in approximately 25% of Non-small Cell Lung Cancer (NSCLC) patients and first specific inhibitors showed promising responses that may be improved by concurrent interference with downstream signaling pathways. Cell lines exhibiting KRAS mutations show specific sensitivities to modulators affecting glucose utilization, signal transduction and cell survival. Novel SOS1-directed inhibitors with a broader anticancer coverage such as BAY-293 and BI-3406 inhibit KRAS through the hindrance of SOS1-KRAS interactions. The aim of this study was to check the putative synergy of BAY-293 with modulators having revealed specific vulnerabilities of KRAS-mutated cell lines. The present investigation tested the cytotoxicity of BAY-293 combinations against a series of Osimertinib-resistant primary NSCLC cell lines using MTT tests and calculation of combination indices according to the Chou-Talalay method. The results show that BAY-293 synergizes with modulators of glucose metabolism, inhibitors of cellular proliferation, several chemotherapeutics and a range of diverse modulators, thus corroborating the chemosensitivities of cells expressing mutated KRAS. In conclusion, BAY-293 exerts cytotoxicity with a wide range of drugs against Osimertinib-resistant primary NSCLC cell lines. The administration of pan-KRAS inhibitors alone may be limited in vivo by toxicity to normal tissues but made feasible by its use as part of suitable drug combinations. This study shows that BAY-293 combinations are active against NSCLC cells not further amenable to mutated EGFR-directed targeted therapy and results likewise hold relevance for pancreatic and colon cancer.

Prognostic Differences of RAS Mutations: Results from the South Australian Metastatic Colorectal Registry

BACKGROUND

Effective targeting of RAS mutations has proven elusive until recently. Novel agents directly targeting KRAS G12C have shown promise in early-phase clinical trials that included patients with metastatic colorectal cancer. Prior reports have suggested that G12C mutation may be predictive of poor outcome.

OBJECTIVE

Assessment of the specific characteristics and prognostic implications of individual RAS mutation subtypes in patients with metastatic colorectal cancer.

PATIENTS AND METHODS

Retrospective review of individual RAS mutation types from the South Australian Metastatic Colorectal Registry between 2006 and 2020.

RESULTS

Of the 5165 patients entered onto the registry, 2305 (45%) had RAS mutation results available. 772 (33%) had a RAS mutation. The nature of the RAS mutation was available in 668 (87% of those with RAS mutation). Rare mutations (outside codons 12 and 13) made up 12.6% of the total. There were numerical differences in survival between the specific RAS mutation subgroups, with the longest median overall survival (30 months) observed in those with G12S mutations. However, there was no statistical difference in survival when comparing the various RAS mutations, including the comparison of G12C to G12S (p = 0.38). Patients with cancer harbouring rare RAS mutations had a median survival of 30 months.

CONCLUSIONS

Whilst the G12S mutation was associated with the longest survival numerically, the observed survival for patients with the most common RAS mutations (G12C, G12V, G12A, G12D and G13D) did not significantly differ.

Role of oncogenic KRAS in the prognosis, diagnosis and treatment of colorectal cancer

Colorectal cancer (CRC) is a heterogeneous disease at the cellular and molecular levels. Kirsten rat sarcoma (KRAS) is a commonly mutated oncogene in CRC, with mutations in approximately 40% of all CRC cases; its mutations result in constitutive activation of the KRAS protein, which acts as a molecular switch to persistently stimulate downstream signaling pathways, including cell proliferation and survival, thereby leading to tumorigenesis. Patients whose CRC harbors KRAS mutations have a dismal prognosis. Currently, KRAS mutation testing is a routine clinical practice before treating metastatic cases, and the approaches developed to detect KRAS mutations have exhibited favorable sensitivity and accuracy. Due to the presence of KRAS mutations, this group of CRC patients requires more precise therapies. However, KRAS was historically thought to be an undruggable target until the development of KRAS^G12C allele-specific inhibitors. These promising inhibitors may provide novel strategies to treat KRAS-mutant CRC. Here, we provide an overview of the role of KRAS in the prognosis, diagnosis and treatment of CRC.

Development and Validation of a Gene Mutation-Associated Nomogram for Hepatocellular Carcinoma Patients From Four Countries

Background: Genomic alteration is the basis of occurrence and development of carcinoma. Specific gene mutation may be associated with the prognosis of hepatocellular carcinoma (HCC) patients without distant or lymphatic metastases. Hence, we developed a nomogram based on prognostic gene mutations that could predict the overall survival of HCC patients at early stage and provide reference for immunotherapy.

Methods: HCC cohorts were obtained from The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) databases. The total patient was randomly assigned to training and validation sets. Univariate and multivariate cox analysis were used to select significant variables for construction of nomogram. The support vector machine (SVM) and principal component analysis (PCA) were used to assess the distinguished effect of significant genes. Besides, the nomogram model was evaluated by concordance index, time-dependent receiver operating characteristics (ROC) curve, calibration curve and decision curve analysis (DCA). Gene Set Enrichment Analysis (GSEA), CIBERSORT, Tumor Immune Dysfunction and Exclusion (TIDE) and Immunophenoscore (IPS) were utilized to explore the potential mechanism of immune-related process and immunotherapy.

Results: A total of 695 HCC patients were selected in the process including 495 training patients and 200 validation patients. Nomogram was constructed based on T stage, age, country, mutation status of DOCK2, EYS, MACF1 and TP53. The assessment showed the nomogram has good discrimination and high consistence between predicted and actual data. Furthermore, we found T cell exclusion was the potential mechanism of malignant progression in high-risk group. Meanwhile, low-risk group might be sensitive to immunotherapy and benefit from CTLA-4 blocker treatment.

Conclusion: Our research established a nomogram based on mutant genes and clinical parameters, and revealed the underlying association between these risk factors and immune-related process.

Targeting steroid hormone receptors for anti-cancer therapy-A review on small molecules and nanotherapeutic approaches

The steroid hormone receptors (SHRs) among nuclear hormone receptors (NHRs) are steroid ligand-dependent transcription factors that play important roles in the regulation of transcription of genes promoted via hormone responsive elements in our genome. Aberrant expression patterns and context-specific regulation of these receptors in cancer, have been routinely reported by multiple research groups. These gave an window of opportunity to target those receptors in the context of developing novel, targeted anticancer therapeutics. Besides the development of a plethora of SHR-targeting synthetic ligands and the availability of their natural, hormonal ligands, development of many SHR-targeted, anticancer nano-delivery systems and theranostics, especially based on small molecules, have been reported. It is intriguing to realize that these cytoplasmic receptors have become a hot target for cancer selective delivery. This is in spite of the fact that these receptors do not fall in the category of conventional, targetable cell surface bound or transmembrane receptors that enjoy over-expression status. Glucocorticoid receptor (GR) is one such exciting SHR that in spite of it being expressed ubiquitously in all cells, we discovered it to behave differently in cancer cells, thus making it a truly druggable target for treating cancer. This review selectively accumulates the knowledge generated in the field of SHR-targeting as a major focus for cancer treatment with various anticancer small molecules and nanotherapeutics on progesterone receptor, mineralocorticoid receptor, and androgen receptor while selectively emphasizing on GR and estrogen receptor. This review also briefly highlights lipid-modification strategy to convert ligands into SHR-targeted cancer nanotherapeutics. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Biology-Inspired Nanomaterials > Lipid-Based Structures Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Proteogenomic characterization of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer with poor patient survival. Toward understanding the underlying molecular alterations that drive PDAC oncogenesis, we conducted comprehensive proteogenomic analysis of 140 pancreatic cancers, 67 normal adjacent tissues, and 9 normal pancreatic ductal tissues. Proteomic, phosphoproteomic, and glycoproteomic analyses were used to characterize proteins and their modifications. In addition, whole-genome sequencing, whole-exome sequencing, methylation, RNA sequencing (RNA-seq), and microRNA sequencing (miRNA-seq) were performed on the same tissues to facilitate an integrated proteogenomic analysis and determine the impact of genomic alterations on protein expression, signaling pathways, and post-translational modifications. To ensure robust downstream analyses, tumor neoplastic cellularity was assessed via multiple orthogonal strategies using molecular features and verified via pathological estimation of tumor cellularity based on histological review. This integrated proteogenomic characterization of PDAC will serve as a valuable resource for the community, paving the way for early detection and identification of novel therapeutic targets.

Apoptosis-inducing activity of synthetic hydrocarbon-stapled peptides in H358 cancer cells expressing KRASG12C

Lung cancers are the leading cause of cancer deaths worldwide and pose a grave threat to human life and health. Non-small cell lung cancer (NSCLC) is the most frequent malignancy occupying 80% of all lung cancer subtypes. Except for other mutations (e.g., KRAS^G12V/D) that are also vital for the occurrence, KRAS^G12C gene mutation is a significant driving force of NSCLC, with a prevalence of approximately 14% of all NSCLC patients. However, there are only a few therapeutic drugs targeting KRAS^G12C mutations currently. Here, we synthesized hydrocarbon-stapled peptide 3 that was much shorter and more stable with modest KRAS^G12C binding affinity and the same anti-tumor effect based on the α-helical peptide mimic SAH-SOS1_A. The stapled peptide 3 effectively induced G2/M arrest and apoptosis, inhibiting cell growth in KRAS-mutated lung cancer cells via disrupting the KRAS-mediated RAF/MEK/ERK signaling, which was verified from the perspective of genomics and proteomics. Peptide 3 also exhibited strong anti-trypsin and anti-chymotrypsin abilities, as well as good plasma stability and human liver microsomal metabolic stability. Overall, peptide 3 retains the equivalent anti-tumor activity of SAH-SOS1_A but with improved stability and affinity, superior to SAH-SOS1_A. Our work offers a structural optimization approach of KRAS^G12C peptide inhibitors for cancer therapy.

On target: Rational approaches to KRAS inhibition for treatment of non-small cell lung carcinoma

Non-small cell lung carcinoma (NSCLC) is a leading cause of cancer death. Approximately one-third of patients with NSCLC have a KRAS mutation. KRAS^G12C, the most common mutation, is found in ~13% of patients. While KRAS was long considered 'undruggable', several novel direct KRAS^G12C inhibitors have shown encouraging signs of efficacy in phase I/II trials and one of these (sotorasib) has recently been approved by the US Food and Drug Administration. This review examines the role of KRAS mutations in NSCLC and the challenges in targeting KRAS. Based on specific KRAS biology, it reports exciting progress, exploring the use of novel direct KRAS inhibitors as monotherapy or in combination with other targeted therapies, chemotherapy, and immunotherapy.

Structure-based inhibitor design of mutant RAS proteins-a paradigm shift

As a member of small GTPase family, KRAS protein is a key physiological modulator of various cellular activities including proliferation. However, mutations of KRAS present in numerous cancer types, most frequently in pancreatic (> 60%), colorectal (> 40%), and lung cancers, drive oncogenic processes through overactivation of proliferation. The G12C mutation of KRAS protein is especially abundant in the case of these types of malignancies. Despite its key importance in human disease, KRAS was assumed to be non-druggable for a long time since the protein seemingly lacks potential drug-binding pockets except the nucleotide-binding site, which is difficult to be targeted due to the high affinity of KRAS for both GDP and GTP. Recently, a new approach broke the ice and provided evidence that upon covalent targeting of the G12C mutant KRAS, a highly dynamic pocket was revealed. This novel targeting is especially important since it serves with an inherent solution for drug selectivity. Based on these results, various structure-based drug design projects have been launched to develop selective KRAS mutant inhibitors. In addition to the covalent modification strategy mostly applicable for G12C mutation, different innovative solutions have been suggested for the other frequently occurring oncogenic G12 mutants. Here we summarize the latest advances of this field, provide perspectives for novel approaches, and highlight the special properties of KRAS, which might issue some new challenges.

What Is New in Biomarker Testing at Diagnosis of Advanced Non-Squamous Non-Small Cell Lung Carcinoma? Implications for Cytology and Liquid Biopsy

The discovery and clinical validation of biomarkers predictive of the response of non-squamous non-small-cell lung carcinomas (NS-NSCLC) to therapeutic strategies continue to provide new data. The evaluation of novel treatments is based on molecular analyses aimed at determining their efficacy. These tests are increasing in number, but the tissue specimens are smaller and smaller and/or can have few tumor cells. Indeed, in addition to tissue samples, complementary cytological and/or blood samples can also give access to these biomarkers. To date, it is recommended and necessary to look for the status of five genomic molecular biomarkers (EGFR, ALK, ROS1, BRAFV600, NTRK) and of a protein biomarker (PD-L1). However, the short- and more or less long-term emergence of new targeted treatments of genomic alterations on RET and MET, but also on others’ genomic alteration, notably on KRAS, HER2, NRG1, SMARCA4, and NUT, have made cellular and blood samples essential for molecular testing. The aim of this review is to present the interest in using cytological and/or liquid biopsies as complementary biological material, or as an alternative to tissue specimens, for detection at diagnosis of new predictive biomarkers of NS-NSCLC.

Targeting KRAS in non-small-cell lung cancer: recent progress and new approaches

Rat sarcoma (RAS) is the most frequently mutated oncogene in human cancer, with Kirsten rat sarcoma (KRAS) being the most commonly mutated RAS isoform. Overall, KRAS accounts for 85% of RAS mutations observed in human cancers and is present in 35% of lung adenocarcinomas (LUADs). While the use of targeted therapies and immune checkpoint inhibitors (CPIs) has drastically changed the treatment landscape of advanced non-small-cell lung cancer (NSCLC) in recent years, historic attempts to target KRAS (both direct and indirect approaches) have had little success, and no KRAS-specific targeted therapies have been approved to date for patients in this molecular subset of NSCLC. With the discovery by Ostrem, Shokat, and colleagues of the switch II pocket on the surface of the active and inactive forms of KRAS, we now have an improved understanding of the complex interactions involved in the RAS family of signaling proteins which has led to the development of a number of promising direct KRAS^G12C inhibitors, such as sotorasib and adagrasib. In previously treated patients with KRAS^G12C-mutant NSCLC, clinical activity has been shown for both sotorasib and adagrasib monotherapy; these data suggest promising new treatment options are on the horizon. With the stage now set for a new era in the treatment of KRAS^G12C-mutated NSCLC, many questions remain to be answered in order to further elucidate the mechanisms of resistance, how best to use combination strategies, and if KRAS^G12C inhibitors will have suitable activity in earlier lines of therapy for patients with advanced/metastatic NSCLC.