NRAS G13D

We demonstrate that RNA-seq is an effective tool for precision medicine in B-ALL by providing comprehensive molecular profiling of leukemia cells, identifying subtype and oncogenic lesions, and stratifying patients for appropriate therapy.

These findings suggest convergent genomic evolution in the MAPK pathway may be a potential mechanism of acquired resistance to FGFRi.

Some SMO inhibitors have been tested in clinical trial and Glasdegib is FDA approved in combination with low dose cytarabine in elderly patients. Given the success of generating these two point mutations, we are currently generating more RAS pathway mutations, including other KRAS mutations, PNTP11 and NF1 mutations. Conclusion These experiments showed: 1) It is possible to induce 2 oncogenic hits in human primary cells and get leukemia in vivo; 2) the KRAS G13D and NRAS G12D mutations shorten the latency of the disease and 3) increase the LSC frequency in secondary mice; 4) a possible involvement of the Hh pathway on stemness/LSC in RAS mutated cells; 5) our experimental approach is robust and very promising to decipher the RAS pathway in human MLL leukemias.

RMC-7977 is a potent, oral small molecule inhibitor of both wild-type and mutant GTP-bound RAS oncoproteins (RASMULTI) and is a preclinical tool compound representative of the clinical candidate RMC-6236, currently in clinical evaluation (NCT05379985)...Gilteritinib and the gilteritinib/venetoclax combination selected for survival of cells harboring NRAS mutations, but RMC-7977 inhibited outgrowth of all cell populations...In vivo studies investigating the tolerability and activity of RMC-7977 and RMC-7977 combinations in RAS mutant/FLT3i-resistant patient-derived xenograft models are ongoing and will be presented. Collectively, our data provide preclinical evidence that combination therapies leveraging RASMULTI(ON) inhibition are effective in suppressing RAS-mutant AML clones, a common mechanism of resistance to currently approved targeted therapies in AML and a current area of high unmet clinical need.

We also revealed a correlation between tumor-infiltrating immune cells in RAS mutated AML microenvironment. Our findings suggest that DUSP1 signaling pathways may regulate Ara-C sensitivity in AML.

P1/2, N=39, Completed, Gritstone bio, Inc. | Active, not recruiting --> Completed | Trial completion date: Dec 2023 --> Mar 2023 | Trial primary completion date: Dec 2023 --> Mar 2023

P2 | "According to liquid biopsy before second- and third-line therapies, treatment sequences are: FOLFIRI + cetuximab (first-line), FOLFOX + cetuximab (second-line); irinotecan + cetuximab (third-line) in patients with plasma ctDNA RAS/BRAFV600E WT tumors. In patients with RAS/BRAFV600E mutant tumors, second-line is FOLFOX + bevacizumab, while third-line is regorafenib or trifluridine/tipiracil (investigator's choice)... Both tumor tissue- and liquid biopsy-based comprehensive genomic profiling by NGS identify additional molecular alterations, that could be involved in resistance to anti-EGFR monoclonal antibodies, as compared to PCR-based tumor tissue analysis. CAPRI 2-GOIM trial will determine if NGS would allow better selection of RAS/BRAFV600E WT mCRC patients for the most appropriate treatments through three sequential lines of therapies."

P1/2, N=39, Active, not recruiting, Gritstone bio, Inc. | Recruiting --> Active, not recruiting | N=144 --> 39

P1/2, N=144, Recruiting, Gritstone bio, Inc. | Trial primary completion date: Dec 2022 --> Dec 2023

Recognizing and referring patients with possible germline mutations for appropriate genetic evaluation and testing provides insight into best patient care strategies along with education and testing opportunities for family members. Leukemia based NGS panels may aid as screening tools for detecting potential pathogenic germline variants.

After 6 courses of FOLFOXIRI with Cetuximab instead of Bevacizumab staging showed regressive metastases...After no response to Lonsurf + Bevacizumab the patient died 12 month after diagnosis. It seems remarkable that in primary chemotherapy-resistant mCRC with KRAS G13D mutation simply by switching antibody therapy, tumor response could be achieved. Switching antibody therapy may be considered for 2 nd line treatment.

Interestingly, the KRAS G13D isogenic line displays elevated PD-L1 expression suggesting the KRAS G13D mutation could be a potential indication for immunotherapy. Overall, these three novel isogenic cell models with endogenous level RAS and MEK1 point mutations provide direct bio-functional evidence demonstrating that acquiring a drug-resistant gene drives tumor cell survival and may simultaneously introduce new indications for combo therapy or immunotherapy in the clinic.

Few reports are available on similar cases. Furthermore, the NRAS c.38 G>A mutation may be a novel pathogenic variant exacerbating RARA translocation-negative acute promyelocytic-like leukemia.

Molecular dynamics simulations, combined with cell-based protein-protein interaction studies, reveal that melanomagenic NRAS mutants form intramolecular contacts that enhance BRAF binding affinity, BRAF-CRAF heterodimer formation, and MAPK > ERK signaling. Along with the allelic series of conditional mouse models we describe, these results establish a mechanistic basis for the enrichment of specific NRAS mutants in human melanoma.

Our findings indicate that dual-driver mutations occur in a rare subset of CRC, often within the same tumor cells and across multiple tumor sites. Their presence and a lower rate of allelic imbalance may be related to dose-dependent signaling within the mitogen-activated protein kinase pathway.

We sought to investigate mechanisms of acquired resistance to FGFRi and approaches to overcome resistance. Longitudinal plasma samples were collected from patients with FGFR pathway alterations enrolled in the futibatinib phase I trial (NCT02052778) and sequenced using a targeted, 73-gene panel... Convergent genomic evolution in the MAPK pathway may be a potential mechanism of acquired resistance to FGFRi therapy. Work is ongoing to determine if targeting co-alterations may enhance the efficacy of FGFRi in FGFR2-fusion driven malignancies.

The Myeloproliferative Neoplasm Diagnostic Assay on the Genexus system provides a comprehensive and rapid solution for molecular diagnosis of MPNs. Careful examination of all filters and IGV sequence analysis are required to reduce false negatives, especially in CALR gene. Secondary confirmation may be necessary for CALR mutations appearing as “No Call” in the “No Filter” setting.

In some cell lines, growth effects were dictated by rescued expression of the tumor suppressor protein p27 (Kip1). The ability of RRSP to irreversibly inhibit cancer cell growth highlights the antitumor potential of RRSP, and further warrants investigation as a potential anti-tumor therapeutic.

Here we evaluated matched pre-treatment and post-treatment specimens from 43 patients treated with the KRAS(G12C) inhibitor sotorasib...A subset of patients in our cohort acquired oncogenic KRAS, NRAS or BRAF mutations, and resistance in this setting may be delayed by co-targeting of ERK signalling intermediates. These findings merit broader evaluation in prospective clinical trials.

Notably, leukemias and MPDs frequently have mutations in KRAS and NRAS at either codon 12 or 61. Our GEMMs recapitulate the tissue-specificity of RAS mutations observed in patients and highlight the unique oncogenic activity of KrasQ61R.

More recently, anti-PD-(L)1 therapies such as nivolumab or pembrolizumab and atezolizumab have been approved as very useful treatments for patients with melanoma. In fact, in the NRAS G13D K1735 murine melanoma cell syngeneic mice model, the combination of belvarafenib with atezolizumab (anti-PD-L1) significantly inhibited tumor growth and effectively induced infiltration of cytotoxic T-cells into tumor tissues. These effects of belvarafenib identified in the above preclinical studies need to be immediately warranted through appropriate clinical trials.

These new experiments further support a mechanism in which cetuximab inhibits wild-type (HRAS and NRAS) signals in KRAS G13D colorectal cancers. Video Abstract.

We first showed the frequency of RAS/RAF mutations in Korean patients with PCM. Screening of these mutations could be considered as a routine clinical test at the time of diagnosis and follow-up due to their influence on clinical outcome, as well as its potential as a therapeutic target.