bims-pimaco 2021-11-21 papers

Cancer Discov. 2021 Nov 19.

Resistant KRAS(G12C) Inhibitor Subclones Exhibit Heterogeneous Alterations.

KRAS(G12C) inhibitor (G12Ci) resistance exhibits a heterogeneous pattern with no one dominant alteration.

DOI: https://doi.org/10.1158/2159-8290.CD-RW2021-167

Cell Death Dis. 2021 Nov 13. 12(11): 1079

Cetuximab promotes RSL3-induced ferroptosis by suppressing the Nrf2/HO-1 signalling pathway in KRAS mutant colorectal cancer.

Jiawen Yang, Jiajie Mo, Juji Dai, Chenqiao Ye, Wei Cen, Xuzhi Zheng, Lei Jiang, Lechi Ye.

Cetuximab is approved for the treatment of metastatic colorectal cancer (mCRC) with RAS wild-type. Nevertheless, the prognosis remains poor and the effectiveness of cetuximab is limited in KRAS mutant mCRC. Recently, emerging evidence has shown that ferroptosis, a newly discovered form of nonapoptotic cell death, is closely related to KRAS mutant cells. Here, we further investigated whether cetuximab-mediated regulation of p38/Nrf2/HO-1 promotes RSL3-induced ferroptosis and plays a pivotal role in overcoming drug resistance in KRAS mutant colorectal cancer (CRC). In our research, we used two KRAS mutant CRC cell lines, HCT116 and DLD-1, as models of intrinsic resistance to cetuximab. The viability of cells treated with the combination of RSL3 and cetuximab was assessed by the CCK-8 and colony formation assays. The effective of cetuximab to promote RSL3-induced ferroptosis was investigated by evaluating lipid reactive oxygen species accumulation and the expression of the malondialdehyde and the intracellular iron assay. Cetuximab therapy contributed to regulating the p38/Nrf2/HO-1 axis, as determined by western blotting and transfection with small interfering RNAs. Cetuximab promoted RSL3-induced ferroptosis by inhibiting the Nrf2/HO-1 in KRAS mutant CRC cells, and this was further demonstrated in a xenograft nude mouse model. Our work reveals that cetuximab enhances the cytotoxic effect of RSL3 on KRAS mutant CRC cells and that cetuximab enhances RSL3-induced ferroptosis by inhibiting the Nrf2/HO-1 axis through the activation of p38 MAPK.

DOI: https://doi.org/10.1038/s41419-021-04367-3

Br J Cancer. 2021 Nov 18.

Characterisation of a novel KRAS G12C inhibitor ASP2453 that shows potent anti-tumour activity in KRAS G12C-mutated preclinical models.

Ayako Nakayama, Takeyuki Nagashima, Yoshihiro Nishizono, Kazuyuki Kuramoto, Kenichi Mori, Kazuya Homboh, Masatoshi Yuri, Masashi Shimazaki.

BACKGROUND: KRAS is one of the most frequently mutated oncogenes in various cancers, and several novel KRAS G12C direct inhibitors are now in clinical trials. Here, we characterised the anti-tumour efficacy of ASP2453, a novel KRAS G12C inhibitor, in preclinical models of KRAS G12C-mutated cancer.
METHODS: We evaluated the in vitro and in vivo activity of ASP2453, alone or in combination with targeted agents and immune checkpoint inhibitors, in KRAS G12C-mutated cancer cells and xenograft models. We also assessed pharmacological differences between ASP2453 and AMG 510, another KRAS G12C inhibitor, using an SPR assay, washout experiments and an AMG 510-resistant xenograft model.
RESULTS: ASP2453 potently and selectively inhibited KRAS G12C-mediated growth, KRAS activation and downstream signalling in vitro and in vivo, and improved the anti-tumour effects of targeted agents and immune checkpoint inhibitors. Further, ASP2453 had more rapid binding kinetics to KRAS G12C protein and showed more potent inhibitory effects on KRAS activation and cell proliferation after washout than AMG 510. ASP2453 also induced tumour regression in an AMG 510-resistant xenograft model.
CONCLUSIONS: ASP2453 is a potential therapeutic agent for KRAS G12C-mutated cancer. ASP2453 showed efficacy in AMG 510-resistant tumours, even among compounds with the same mode of action.

DOI: https://doi.org/10.1038/s41416-021-01629-x

J Med Chem. 2021 Nov 17.

Targeting a Novel KRAS Binding Site: Application of One-Component Stapling of Small (5-6-mer) Peptides.

Gabriele Fumagalli, Rodrigo J Carbajo, J Willem M Nissink, Jonathan Tart, Rongxuan Dou, Andrew P Thomas, David R Spring.

RAS proteins are central in the proliferation of many types of cancer, but a general approach toward the identification of pan-mutant RAS inhibitors has remained unresolved. In this work, we describe the application of a binding pharmacophore identified from analysis of known RAS binding peptides to the design of novel peptides. Using a chemically divergent approach, we generated a library of small stapled peptides from which we identified compounds with weak binding activity. Exploration of structure-activity relationships (SARs) and optimization of these early compounds led to low-micromolar binders of KRAS that block nucleotide exchange.

DOI: https://doi.org/10.1021/acs.jmedchem.1c01334

Front Pharmacol. 2021 ;12 739501

Therapeutic Suppression of FAK-AKT Signaling Overcomes Resistance to SHP2 Inhibition in Colorectal Carcinoma.

Ye Li, Yuncang Yuan, Fan Zhang, Aizhen Guo, Fuao Cao, Mengmeng Song, Yating Fu, Xiaowen Xu, Hao Shen, Shangyong Zheng, Yamin Pan, Wenjun Chang.

SHP2 mediates signaling from multiple receptor tyrosine kinases (RTKs) to extracellular signal-regulated kinase (ERK) and Ser and Thr kinase AKT, and its inhibitors offer an unprecedented opportunity for cancer treatment. Although the ERK signaling variation after SHP2 inhibition has been well investigated, the AKT signaling variation in colorectal carcinoma (CRC) is still unknown. Therefore, we performed immunohistochemistry and bioinformatics analyses to explore the significance of p-SHP2 in CRC. A panel of CRC cell lines with the SHP2 inhibitor, SHP099, was used to assess the effects on viability and signaling. The inhibitors of AKT and focal adhesion kinase (FAK) signaling were examined in combination with SHP099 as potential strategies to enhance the efficacy and overcome resistance. Frequent resistance to the SHP2 inhibitor was observed in CRC cells, even in those without RAS mutations. We observed rapid adaptive reactivation of the AKT pathway in response to SHP2 inhibition, possibly driven by the reactivation of RTKs or released p-FAK. High baseline p-FAK may also be associated with CRC cell resistance to SHP2 inhibition. Co-inhibition of FAK abrogated the feedback reactivation of AKT in response to SHP2 inhibition. Moreover, the combined inhibition of SHP2 with AKT or FAK resulted in sustained AKT pathway suppression and improved antitumor efficacy in vitro and in vivo. Our study found that reactivation of the AKT pathway is a key mechanism of adaptive resistance to SHP2 inhibition, highlighting the potential significance of AKT and FAK inhibition strategies to enhance the efficacy of SHP2 inhibitors in CRC treatment.

Keywords: AKT rebound; FAK; SHP2; colorectal carcinoma; drug resistance

DOI: https://doi.org/10.3389/fphar.2021.739501

J Biomed Sci. 2021 Nov 15. 28(1): 77

CRISPR and KRAS: a match yet to be made.

Guzide Bender, Rezan Fahrioglu Yamaci, Bahar Taneri.

CRISPR (clustered regularly interspaced short palindromic repeats) systems are one of the most fascinating tools of the current era in molecular biotechnology. With the ease that they provide in genome editing, CRISPR systems generate broad opportunities for targeting mutations. Specifically in recent years, disease-causing mutations targeted by the CRISPR systems have been of main research interest; particularly for those diseases where there is no current cure, including cancer. KRAS mutations remain untargetable in cancer. Mutations in this oncogene are main drivers in common cancers, including lung, colorectal and pancreatic cancers, which are severe causes of public health burden and mortality worldwide, with no cure at hand. CRISPR systems provide an opportunity for targeting cancer causing mutations. In this review, we highlight the work published on CRISPR applications targeting KRAS mutations directly, as well as CRISPR applications targeting mutations in KRAS-related molecules. In specific, we focus on lung, colorectal and pancreatic cancers. To date, the limited literature on CRISPR applications targeting KRAS, reflect promising results. Namely, direct targeting of mutant KRAS variants using various CRISPR systems resulted in significant decrease in cell viability and proliferation in vitro, as well as tumor growth inhibition in vivo. In addition, the effect of mutant KRAS knockdown, via CRISPR, has been observed to exert regulatory effects on the downstream molecules including PI3K, ERK, Akt, Stat3, and c-myc. Molecules in the KRAS pathway have been subjected to CRISPR applications more often than KRAS itself. The aim of using CRISPR systems in these studies was mainly to analyze the therapeutic potential of possible downstream and upstream effectors of KRAS, as well as to discover further potential molecules. Although there have been molecules identified to have such potential in treatment of KRAS-driven cancers, a substantial amount of effort is still needed to establish treatment strategies based on these discoveries. We conclude that, at this point in time, despite being such a powerful directed genome editing tool, CRISPR remains to be underutilized for targeting KRAS mutations in cancer. Efforts channelled in this direction, might pave the way in solving the long-standing challenge of targeting the KRAS mutations in cancers.

Keywords: CRISPR; CRISPR-Cas; Cancer; Colon cancer; Genome editing; KRAS; Lung cancer; Mutation; NSCLC; Pancreatic cancer

DOI: https://doi.org/10.1186/s12929-021-00772-0

J Clin Invest. 2021 Nov 15. pii: e150335. [Epub ahead of print]131(22):

Therapeutic implications of activating noncanonical PIK3CA mutations in head and neck squamous cell carcinoma.

Alpelisib selectively inhibits the p110α catalytic subunit of PI3Kα and is approved for treatment of breast cancers harboring canonical PIK3CA mutations. In head and neck squamous cell carcinoma (HNSCC), 63% of PIK3CA mutations occur at canonical hotspots. The oncogenic role of the remaining 37% of PIK3CA noncanonical mutations is incompletely understood. We report a patient with HNSCC with a noncanonical PIK3CA mutation (Q75E) who exhibited a durable (12 months) response to alpelisib in a phase II clinical trial. Characterization of all 32 noncanonical PIK3CA mutations found in HNSCC using several functional and phenotypic assays revealed that the majority (69%) were activating, including Q75E. The oncogenic impact of these mutations was validated in 4 cellular models, demonstrating that their activity was lineage independent. Further, alpelisib exhibited antitumor effects in a xenograft derived from a patient with HNSCC containing an activating noncanonical PIK3CA mutation. Structural analyses revealed plausible mechanisms for the functional phenotypes of the majority of the noncanonical PIK3CA mutations. Collectively, these findings highlight the importance of characterizing the function of noncanonical PIK3CA mutations and suggest that patients with HNSCC whose tumors harbor activating noncanonical PIK3CA mutations may benefit from treatment with PI3Kα inhibitors.

Keywords: Head and neck cancer; Oncology

DOI: https://doi.org/10.1172/JCI150335