Biology subjects

Le, A. T.

Publications and source records attributed to Le, A. T..

3 recordsLinked to original sources

bioRxiv2022

Evaluation of KRASG12C Inhibitor Responses in Novel Murine KRASG12C Lung Cancer Cell Line Models

The KRAS(G12C) mutation is the most common genetic mutation in North American lung adenocarcinoma patients. Recently, direct inhibitors of the KRASG12C protein have been developed and demonstrate clinical response rates of 37-43%. Importantly, these agents fail to generate durable therapeutic responses with median progression-free survival of ~6.5 months. To provide models for further preclinical improvement of these inhibitors, we generated three novel murine KRASG12C-driven lung cancer cell lines. The co-occurring NRASQ61L mutation in KRASG12C-positive LLC cells was deleted and the KRASG12V allele in CMT167 cells was edited to KRASG12C with CRISPR/Cas9 methods. Also, a novel murine KRASG12C line, mKRC.1, was established from a tumor generated in a genetically-engineered mouse model. The three lines exhibit similar in vitro sensitivities to KRASG12C inhibitors (MRTX-1257, AMG-510), but distinct in vivo responses to MRTX-849 ranging from progressive growth with orthotopic LLC-NRAS KO tumors to marked shrinkage with mKRC.1 tumors. All three cell lines exhibited synergistic in vitro growth inhibition with MRTX-1257 and the SHP2 inhibitor, RMC-4550 and the MRTX-849/RMC-4550 combination yielded tumor shrinkage in orthotopic LLC-NRAS KO tumors propagated in syngeneic mice. Notably, this synergistic combination response was lost in athymic nu/nu mice, supporting a growing literature demonstrating a role for adaptive immunity in the response to this class of drugs. These new models of murine KRASG12C mutant lung cancer should prove valuable for identifying improved therapeutic combination strategies with KRASG12C inhibitors. Contribution to the Field StatementThe development of KRASG12C inhibitors has not impacted treatment of lung cancers bearing the KRASG12C mutation to the degree that tyrosine kinase inhibitors have changed the treatment outcomes for patients bearing oncogenic mutations in receptor tyrosine kinases. Thus, the field is now exploring combination strategies with KRASG12C inhibitors that may enhance their clinical benefit. Moreover, published findings indicate that host immunity contributes to efficacy of oncogene-directed inhibitors including KRASG12C inhibitors. Thus, these novel murine KRASG12C-driven lung cancer cell lines will provide valuable models for preclinical evaluation of novel drug combinations in immune competent hosts.

cancer biology↗

bioRxiv2022

Loss of Spindly sensitizes EML4-ALK v3 lung cancer cells to HSP90 inhibitors

Heat Shock Protein 90 inhibitors (HSP90i) have shown activity in EML4-ALK+ non-small cell lung cancer (NSCLC) patients but clinical responses have been heterogeneous. It has been suggested that distinct EML4-ALK variants may have a differential impact on the response to HSP90 inhibition. Here, we show that NSCLC cells harboring the most common EML4-ALK variant 1 (v1) or variant 3 (v3) are in fact similarly sensitive to HSP90i. To discover new genetic alterations that could be involved in stratifying sensitivity, we performed a genome-wide CRISPR/Cas9 knockout screen and found that loss of Spindly increases the sensitivity of EML4-ALK v3, but not v1, NSCLC cells to low concentrations of HSP90i from three distinct chemical families. Upon loss of Spindly, prolonged exposure to low concentrations of HSP90i impairs chromosome congression and cellular fitness. Collectively, our data suggest that mutations leading to loss of Spindly in EML4-ALK v3 NSCLC patients may increase sensitivity to low doses of HSP90i.

cancer biology↗

bioRxiv2022

Adaptive immunity is required for durable responses to alectinib in murine models of EML4-ALK lung cancer

PurposeLung cancers bearing oncogenic EML4-ALK fusions respond to targeted tyrosine kinase inhibitors (TKIs; e.g. alectinib), with variation in the degree of shrinkage and duration of treatment (DOT). We previously demonstrated a positive association of a TKI-induced interferon gamma (IFN{gamma}) transcriptional response with DOT in EGFR-mutant lung cancers. Herein, we used murine models of EML4-ALK lung cancer to test a role for host immunity in the therapeutic response to alectinib. Experimental DesignThree murine EML4-ALK cell lines (EA1, EA2, EA3) were implanted orthotopically into the lungs of immunocompetent and immunodeficient mice and treated with alectinib. Tumor volumes were serially measured by CT. Immune cell content was measured by flow cytometry, multispectral immunofluorescence and CyTOF. Transcriptional responses to alectinib were assessed by RNAseq and secreted chemokines were measured by ELISA. ResultsAll cell lines were sensitive to alectinib in vitro. EA1 and EA3 tumors retained residual disease that rapidly progressed upon termination of treatment while EA2 tumors were eliminated by TKI treatment. Alectinib induced inflammatory transcriptional programs and multiple chemokines in all cell lines while untreated tumors exhibited distinct baseline chemokine expression patterns and content of CD8+ T cells and myeloid subsets. When propagated in immune-deficient mice, all three cell line-derived lung tumor models exhibited significant shrinkage followed by prompt progression despite continuous alectinib treatment. ConclusionsThe findings support an hypothesis that host and TKI-stimulated production of chemokines by tumor cells promotes functional engagement of adaptive immune cells within the tumor microenvironment that enhances the durability and depth of TKI response. Statement of Translational RelevancePatients with metastatic lung cancer harboring ALK fusions are treated with targeted tyrosine kinase inhibitors (TKI) in the first line setting. Despite bearing the same driver oncogene, patients experience a range of tumor burden reduction and variable amounts of residual disease. Residual disease burden associates with patient survival and contributes to the emergence of drug resistance yielding treatment failure. The factors mediating this differential response to TKI and residual disease are incompletely understood. Our group has developed a panel of murine ALK driven lung cancer cell lines that reproducibly show differences in the depth and duration of response when implanted into immunocompetent mice. Data using this model indicate that the presence of CD8+ T cells is a major contributor to the depth and duration of response. These models will be critical in developing rational combination therapies to augment the immune microenvironment engagement along with TKIs to improve outcomes for these patients.

cancer biology↗