KRAS mutations are among the most commonly occurring mutations in cancer. After being deemed undruggable for decades, KRAS G12C specific inhibitors showed that small molecule inhibitors can be ...developed against this notorious target. At the same time, there is still no agent that could target KRAS G12D which is the most common KRAS mutation and is found in the majority of KRAS-mutated pancreatic tumors. Nevertheless, significant progress is now being made in the G12D space with the development of several compounds that can bind to and inhibit KRAS G12D, most notably MRTX1133. Exciting advances in this field also include an immunotherapeutic approach that uses adoptive T-cell transfer to specifically target G12D in pancreatic cancer. In this mini-review, we discuss recent advances in KRAS G12D targeting and the potential for further clinical development of the various approaches.
The Kirsten rat sarcoma viral (KRAS) oncogene is the most frequently mutated isoform of RAS, associated with 85 % of RAS-driven cancers. KRAS functions as a signaling hub, participating in various ...cellular signaling pathways and regulating a wide range of important activities, including cell proliferation, differentiation, growth, metabolism, and migration. Despite being the most frequently altered oncogenic protein in solid tumors, over the past four decades, KRAS has historically been considered “undruggable" owing to a lack of pharmacologically targetable pockets within the mutant isoforms. However, improvements in drug design and development have culminated in the development of selective inhibitors for KRAS mutants. Recent developments have led to the successful targeting of the KRASG12C mutant through covalent inhibitors that exploit the unique cysteine residue introduced by the mutation at 12th position. These inhibitors bind covalently to C12, locking KRAS in its inactive GDP-bound state and preventing downstream signaling. Some of these inhibitors have shown encouraging results in KRASG12C mutant cancer patients but suffer from drug resistance, toxicity, and low therapeutic efficacy. Recently, there have been great advancements in the discovery of drugs that directly target the switch I (S-I), switch-II (S-II) and S-I/II interface sites of KRAS mutant proteins. These include KRASG12C inhibitors like AMG510 (Sotorasib) and MRTX849 (Adagrasib), which have got FDA approval for non-small cell lung cancer harboring the KRASG12C mutation. There is no approved drug for cancers harboring other KRAS mutations, although efforts have expanded to target other KRAS mutations and the Switch I/II interface, aiming to disrupt KRAS-driven oncogenic signaling. Structure-activity relationship (SAR) studies have been instrumental in optimizing the binding affinity, selectivity, and pharmacokinetic properties of these inhibitors, leading to the development of promising therapeutic agents like Sotorasib and Adagrasib. This review provides an overview of the KRAS pathway, KRAS binding sites, strategies for direct and indirect inhibition using small molecules, and SAR based on the co-crystal structures of inhibitors with KRAS mutants which is expected to offer new hope for patients with KRAS-driven cancers through the development of new KRAS-targeted drugs.
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•Cancer remains the leading cause of global mortality, accounting for one in every six fatalities.•KRAS, a GTPase, is frequently mutated in cancers.•The development of KRAS inhibitors is a significant advancement in targeted cancer therapy.•There is a need of new drug discovery and optimization for KRAS mutants.•Analysis of the resolved co-crystal structures of KRAS inhibitors have provided insights to guide new drug discovery.
KRAS G12V is one of the most common KRAS mutation variants in lung adenocarcinoma (LUAD), and yet its prognostic value is still unrevealed. In this study, we investigated the clinicopathologic ...characteristics and prognostic value of the KRAS G12V mutation in LUAD.
Data of 3829 patients who underwent LUAD resection between 2008 and 2020 were collected. Mutations were classified as wild-type, G12V, or non-G12V. The clinicopathologic characteristics, postoperative outcomes, and recurrence pattern were analyzed among groups.
In total, 3554 patients were wild-type and 275 patients harbored a KRAS mutation: 60 patients with G12V (22.2%) and 215 patients with non-G12V (77.8%). The KRAS G12V mutation was more frequent in male patients, older patients (≥60 years), former/current smokers, those patients with radiologic solid nodules, and those with highly invasive histologic subtypes. Tumors carrying KRAS G12V mutation exhibited elevated programmed death-ligand 1 expression in comparison with wild-type tumors. KRAS G12V was more prevalent in older patients and had less lymphovascular invasion compared with other mutation types. FGF3, RET, and KDR co-mutations occurred more frequently in the KRAS G12V group. Multivariate analysis demonstrated that the KRAS G12V mutation was an independent prognostic factor in stage Ⅰ tumors, whereas the KRAS non-G12V mutation was not. KRAS G12V was associated with early recurrence and locoregional recurrence.
The KRAS G12V mutation was associated with aggressive clinical-pathologic phenotype and early recurrence. To note, this mutation exhibited a significantly worse prognosis in patients with part-solid and stage Ⅰ lung adenocarcinoma. Meanwhile, the prognostic significance of KRAS G12C and G12V variants was comparable.
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KRAS is the most commonly mutated oncogene in human tumors, especially in lung, pancreatic, and colorectal cancers. Small-molecule inhibitors targeting mutant KRASG12C demonstrated promising ...anti-tumor effect in patients with non-small cell lung cancer harboring KRASG12C mutation, while the intrinsic and acquired drug resistance occurred frequently and might be inevitable. Unlike the protein-level inhibition approach, gene silencing/editing tools for DNA-level knockout and RNA-level knockdown of mutant KRAS may be advantageous since these approaches directly eliminate the production of mutant KRAS-encoded protein. An in-depth understanding of KRAS biology, drug resistance to KRASG12C inhibitors and gene silencing/editing methods applied for anti-KRAS therapy may give new insight into the therapeutic strategy for cancer treatment.
Mutant KRAS, the most frequently occurring (∼30%) driver oncogene in lung adenocarcinoma, induces normal epithelial cells to undergo senescence. This phenomenon, called “oncogene-induced senescence ...(OIS)”, prevents mutant KRAS-induced malignant transformation. We have previously reported that mutant KRASV12 induces OIS in a subset of normal human bronchial epithelial cell line immortalized with hTERT and Cdk4. Understanding the mechanism and efficacy of this important cancer prevention mechanism is a key knowledge gap. Therefore, this study investigates mutant KRASV12-induced OIS in upregulated telomerase combined with the p16/RB pathway inactivation in normal bronchial epithelial cells. The normal (non-transformed and non-tumorigenic) human bronchial epithelial cell line HBEC3 (also called “HBEC3KT”), immortalized with hTERT (“T”) and Cdk4 (“K”), was used in this study. HBEC3 that expressed mutant KRASV12 in a doxycycline-regulated manner was established (designated as HBEC3-RIN2). Controlled induction of mutant KRASV12 expression induced partial epithelial-to-mesenchymal transition in HBEC3-RIN2 cells, which was associated with upregulated expression of ZEB1 and SNAIL. Mutant KRASV12 caused the majority of HBEC3-RIN2 to undergo morphological changes; suggestive of senescence, which was associated with enhanced autophagic flux. Upon mutant KRASV12 expression, only a small HBEC3-RIN2 cell subset underwent senescence, as assessed by a senescence-associated β-galactosidase staining (SA-βG) method. Furthermore, mutant KRASV12 enhanced cell growth, evaluated by colorimetric proliferation assay, and liquid and soft agar colony formation assays, partially through increased phosphorylated AKT and ERK expression but did not affect cell division, or cell cycle status. Intriguingly, mutant KRASV12 reduced p53 protein expression but increased p21 protein expression by prolonging its half-life. These results indicate that an hTERT/Cdk4 -immortalized normal bronchial epithelial cell line is partially resistant to mutant KRASV12-induced senescence. This suggests that OIS does not efficiently suppress KRASV12-induced transformation in the context of the simultaneous occurrence of telomerase upregulation and inactivation of the p16/Rb pathway.
•KRASV12 induced partial epithelial-to-mesenchymal transition in an hTERT/Cdk4-immortalized normal bronchial epithelial cells (HBEC3-RIN2).•Upon KRASV12 expression, only a small HBEC3-RIN2 cell subset underwent oncogene-induced senescence (OIS).•KRASV12 reduced p53 protein expression but increased p21 protein expression by prolonging its half-life in HBEC3-RIN2.•Our results indicate that HBEC3-RIN2 is partially resistant to KRASV12-induced OIS.
Pancreatic ductal adenocarcinoma (PDAC) is almost universally fatal. The annual number of deaths equals the number of newly diagnosed cases, despite maximal treatment. The overall 5-year survival ...rate of <5% has remained stubbornly unchanged over the last 30 years, despite tremendous efforts in preclinical and clinical science. There is unquestionably an urgent need to further improve our understanding of pancreatic cancer biology, treatment response and relapse, and to identify novel therapeutic targets. Rigorous research in the field has uncovered genetic aberrations that occur during PDAC development and progression. In most cases, PDAC is initiated by oncogenic mutant KRAS, which has been shown to drive pancreatic neoplasia. However, all attempts to target KRAS directly have failed in the clinic and KRAS is widely assumed to be undruggable. This has led to intense efforts to identify druggable critical downstream targets and nodes orchestrated by mutationally activated KRAS. This includes context-specific KRAS effector pathways, synthetic lethal interaction partners and KRAS-driven metabolic changes. Here, we review recent advances in oncogenic KRAS signalling and discuss how these might benefit PDAC treatment in the future.
Lung cancer is one of the most common causes of cancer-related deaths, and non-small-cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancer cases. Kirsten rat sarcoma virus ...(KRAS), one of the three subtypes of the RAS family, is the most common oncogene involved in human cancers and encodes the key signaling proteins in tumors. Oncogenic KRAS mutations are considered the initiating factors in 30% of NSCLC cases, accounting for the largest proportion of NSCLC cases associated with driver mutations. Because effective inhibition of the related functions of KRAS with traditional small-molecule inhibitors is difficult, the KRAS protein is called an “undruggable target.” However, in recent years, the discovery of a common mutation in the KRAS gene, glycine 12 mutated to cysteine (G12C), has led to the design and synthesis of covalent inhibitors that offer novel strategies for effective targeting of KRAS. In this review, we have summarized the structure, function, and signal transduction pathways of KRAS and discussed the available treatment strategies and potential treatment prospects of KRAS mutation subtypes (especially G12C, G12V, and G12D) in NSCLC, thus providing a reference for selecting KRAS mutation subtypes for the treatment of NSCLC.
RAS proteins are binary switches, cycling between ON and OFF states during signal transduction. These switches are normally tightly controlled, but in RAS-related diseases, such as cancer, ...RASopathies, and many psychiatric disorders, mutations in the RAS genes or their regulators render RAS proteins persistently active. The structural basis of the switch and many of the pathways that RAS controls are well known, but the precise mechanisms by which RAS proteins function are less clear. All RAS biology occurs in membranes: a precise understanding of RAS’ interaction with membranes is essential to understand RAS action and to intervene in RAS-driven diseases.
RAS proteins have been linked to several cancers. The identification of RAS regulatory proteins has provided deeper insights into the biochemical and biophysical properties of RAS proteins as well as shed light into ways to target them pharmacologically.
Despite significant advancements in the treatment of other cancers, pancreatic ductal adenocarcinoma (PDAC) remains one of the world's deadliest cancers. More than 90% of PDAC patients harbor a ...Kirsten rat sarcoma (KRAS) gene mutation. Although the clinical potential of anti-KRAS therapies has long been realized, all initial efforts to target KRAS were unsuccessful. However, with the recent development of a new generation of KRAS-targeting drugs, multiple KRAS-targeted treatment options for patients with PDAC have entered clinical trials. In this review, we provide an overview of current standard of care treatment, describe RAS signaling and the relevance of KRAS mutations, and discuss RAS isoform- and mutation-specific differences. We also evaluate the clinical efficacy and safety of mutation-selective and multi-selective inhibitors, in the context of PDAC. We then provide a comparison of clinically relevant KRAS inhibitors to second-line PDAC treatment options. Finally, we discuss putative resistance mechanisms that may limit the clinical effectiveness of KRAS-targeted therapies and provide a brief overview of promising therapeutic approaches in development that are focused on mitigating these resistance mechanisms.