Recent advances in the development of inhibitors targeting KRAS-G12C and its related pathways

Design, synthesis and biological evaluation of pyrrolopyrimidine urea derivatives as novel KRASG12C inhibitors for the treatment of cancer

The KRASG12C mutation, which occurs in approximately 14 % of lung adenocarcinomas, has recently become a crucial target for therapy via small molecules that covalently bind to the mutated cysteine. In this study, a novel series of pyrrolopyrimidine derivatives was rationally designed and synthesized, employing a structure-based drug design strategy. Through structure-activity relationship (SAR) analysis, compound SK-17 emerged as a direct and highly potent inhibitor of KRASG12C. Cellular assays illustrated that SK-17 exhibits potent antiproliferative effects, induces apoptosis, possesses anti-tumor metastasis properties, and effectively inhibits the downstream KRAS pathway in a dose-dependent manner. Moreover, the synergistic enhancement observed when SK-17 is combined with SHP2 inhibitors in vitro underscores its innovative potential in combinatorial therapies. In the xenograft mouse model, SK-17 demonstrated outstanding tumor growth suppression with good safety. Importantly, the in vivo test results show that compound SK-17 has a superior PK profile and lower toxicity in zebrafish test. These results demonstrated the potential of SK-17 with novel scaffold as a promising lead compound targeting KRASG12C to guide in-depth structural optimization.

Advances and Challenges in RAS Signaling Targeted Therapy in Leukemia

RAS mutations are prevalent in leukemia, including mutations at G12, G13, T58, Q61, K117, and A146. These mutations are often crucial for tumor initiation, maintenance, and recurrence. Although much is known about RAS function in the last 40 years, a substantial knowledge gap remains in understanding the mutation-specific biological activities of RAS in cancer and the approaches needed to target specific RAS mutants effectively. The recent approval of KRASG12C inhibitors, adagrasib and sotorasib, has validated KRAS as a direct therapeutic target and demonstrated the feasibility of selectively targeting specific RAS mutants. Nevertheless, KRASG12C remains the only RAS mutant successfully targeted with FDA-approved inhibitors for cancer treatment in patients, limiting its applicability for other oncogenic RAS mutants, such as G12D, in leukemia. Despite these challenges, new approaches have generated optimism about targeting specific RAS mutations in an allele-dependent manner for cancer therapy, supported by compelling biochemical and structural evidence, which inspires further exploration of RAS allele-specific vulnerabilities. This review will discuss the recent advances and challenges in the development of therapies targeting RAS signaling, highlight emerging therapeutic strategies, and emphasize the importance of allele-specific approaches for leukemia treatment.

Redefining Therapeutic Approaches in Colorectal Cancer: Targeting Molecular Pathways and Overcoming Resistance

Colorectal cancer (CRC) arises through a combination of genetic and epigenetic alterations that affect key pathways involved in tumor growth and progression. This review examines the major molecular pathways driving CRC, including Chromosomal Instability (CIN), Microsatellite Instability (MSI), and the CpG Island Methylator Phenotype (CIMP). Key mutations in genes such as APC, KRAS, NRAS, BRAF, and TP53 activate signaling pathways like Wnt, EGFR, and PI3K/AKT, contributing to tumorigenesis and influencing responses to targeted therapies. Resistance mechanisms, including mutations that bypass drug action, remain challenging in CRC treatment. This review highlights the role of molecular profiling in guiding the use of targeted therapies such as tyrosine kinase inhibitors and immune checkpoint inhibitors. Novel combination treatments are also discussed as strategies to improve outcomes and overcome resistance. Understanding these molecular mechanisms is critical to advancing personalized treatment approaches in CRC and improving patient prognosis.

Structure-activity relationships of middle-size cyclic peptides, KRAS inhibitors derived from an mRNA display

Cyclic peptides are attracting attention as therapeutic agents due to their potential for oral absorption and easy access to tough intracellular targets. LUNA18, a clinical KRAS inhibitor, was transformed-without scaffold hopping-from the initial hit by using an mRNA display library that met our criteria for drug-likeness. In drug discovery using mRNA display libraries, hit compounds always possess a site linked to an mRNA tag. Here, we describe our examination of the Structure-Activity Relationship (SAR) using X-ray structures for chemical optimization near the site linked to the mRNA tag, equivalent to the C-terminus. Structural modifications near the C-terminus demonstrated a relatively wide range of tolerance for side chains. Furthermore, we show that a single atom modification is enough to change the pharmacokinetic (PK) profile. Since there are four positions where side chain modification is permissible in terms of activity, it is possible to flexibly adjust the pharmacokinetic profile by structurally optimizing the side chain. The side chain transformation findings demonstrated here may be generally applicable to hits obtained from mRNA display libraries.

DNA encoded peptide library for SARS-CoV-2 3CL protease covalent inhibitor discovery and profiling

Covalent protease inhibitors serve as valuable tools for modulating protease activity and are essential for investigating the functions of protease targets. These inhibitors typically consist of a recognition motif and a covalently reactive electrophile. Substrate peptides, featuring residues capable of fitting into the substrate pockets of proteases, undergo chemical modification at the carbonyl carbon of the P1 residue with an electrophile and have been widely applied in the development of covalent inhibitors. In this study, we utilized a DNA-encoded peptide library to replicate peptide binder sequences and introduced a vinyl sulfone warhead at the C-termini to construct the DNA-encoded peptide covalent inhibitor library (DEPCIL) for targeting cysteine proteases. Screening results toward 3CL protease demonstrated the efficacy of this library, not only in identifying protease inhibitors, but also in discovering amino acids that can conform to aligned protease pockets. The identified peptide sequences provide valuable insight into the amino acid preferences within substrate binding pockets, and our novel technology is indicative of the potential for similar strategies to discover covalent inhibitors and profile binding preferences of other proteases.

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

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

Targeted Combination Therapies: A New Frontier in the Treatment of TP53 and KRAS Mutation-Associated Cancers

This Patent Highlight discusses novel therapeutic strategies for treating cancers associated with TP53 or KRAS mutations, particularly colorectal, pancreatic, and non-small-cell lung cancers. It focuses on the use of combination therapies involving two distinct compounds and a KRAS inhibitor. Researchers are exploring the effectiveness of these combined therapies in patient treatment and investigating their potential applications in drug manufacturing. With cancer being a global health challenge, these innovative strategies could present a breakthrough in enhancing survival rates and improving the quality of life for patients.

Synthetic Approaches to Piperazine-Containing Drugs Approved by FDA in the Period of 2011-2023

The piperazine moiety is often found in drugs or in bioactive molecules. This widespread presence is due to different possible roles depending on the position in the molecule and on the therapeutic class, but it also depends on the chemical reactivity of piperazine-based synthons, which facilitate its insertion into the molecule. In this paper, we take into consideration the piperazine-containing drugs approved by the Food and Drug Administration between January 2011 and June 2023, and the synthetic methodologies used to prepare the compounds in the discovery and process chemistry are reviewed.

Nucleic Acid-Based Approaches to Tackle KRAS Mutant Cancers

Activating mutations in KRAS are highly relevant to various cancers, driving persistent efforts toward the development of drugs that can effectively inhibit KRAS activity. Previously, KRAS was considered 'undruggable'; however, the recent advances in our understanding of RNA and nucleic acid chemistry and delivery formulations have sparked a paradigm shift in the approach to KRAS inhibition. We are currently witnessing a large wave of next-generation drugs for KRAS mutant cancers-nucleic acid-based therapeutics. In this review, we discuss the current progress in targeting KRAS mutant tumors and outline significant developments in nucleic acid-based strategies. We delve into their mechanisms of action, address existing challenges, and offer insights into the current clinical trial status of these approaches. We aim to provide a thorough understanding of the potential of nucleic acid-based strategies in the field of KRAS mutant cancer therapeutics.