Project description:Whole exome sequencing was performed on set of 48 DNA samples obtained from 16 EGFR mutated NSCLC patients whose tumors progressed following EGFR-TKI treatment. The DNA samples included baseline biopsy, rebiopsy and blood from the same patient. By comparing the variants in rebiopsy tumors and baseline tumors we aim to understand the genomic alterations responsible for the development of EGFR-TKI resistance in NSCLC patients.
Project description:Starting with H3122 cells, which harbor the EML4-ALK E13;A20 fusion and are known to be sensitive to ALK tyrosine kinase inhibitors, we generated isogenic pairs of ALK TKI sensitive and ALK TKI resistant cell lines using established methods (see Chmeliecki, J et al Science Trans Med 2011). We modeled resistance against the currently FDA approved ALK TKI, crizotinib (also called PF-1066). We also modeled resistance against a novel more potent ALK inhibitor, X-376 (ref: Lovly, CM et al Cancer Research 2011). We compared gene expression profiles between the 'parental' (ALK TKI sensitive) H3122 cells and the drug resistant cells (H3122 CR for Crizotinib resistant cells and H3122 XR for X-376 resistant cells).
Project description:Intrinsic and acquired resistance represent major obstacles to optimize outcomes in epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) targeted therapy in lung adenocarcinoma (LUAD). Hence, a deeper understanding of EGFR-TKI resistance mechanisms in LUAD will potentially assist in formulating strategies to delay or overcome such resistance. Herein, it was observed that trefoil factor 3 (TFF3) is a crucial mediator of the LUAD EGFR-TKI response. TFF3 conferred intrinsic resistance to EGFR inhibition in LUAD by promotion of EGFR activation. TFF3 expression was also increased in acquired EGFR-TKI resistant LUAD, accompanied by reduced EGFR activation. YAP, a key mediator of the Hippo signaling, was positively regulated by TFF3 by post-transcriptional mechanisms and was responsible for acquired EGFR-TKI resistance mediated by TFF3. Inhibition of TFF3 by a small molecule inhibitor not only enhanced EGFR-TKI sensitivity in LUAD cells but also restored the sensitivity of acquired EGFR-TKI resistant LUAD cells to EGFR-TKIs in vitro and in vivo. These findings demonstrate a pivotal function of TFF3 in mediating EGFR-TKI resistance in LUAD and may offer a potential therapeutic mechanism for delaying or overcoming resistance to EGFR-TKIs.
Project description:In this report, we revealed that branched chain amino acid transaminase 1 (BCAT1) is highly enriched in both mouse and human TKI-resistant CML cells. Leukemia was almost completely abrogated upon BCAT1 knockdown during transplantation in a BCR-ABLT315I-induced murine TKI-resistant CML model . Moreover, knockdown of BCAT1 led to a dramatic decrease in the proliferation of TKI-resistant human leukemia cell lines. BCAA/BCAT1 signaling enhanced the phosphorylation of CREB, which is required for maintenance of TKI-resistant CML cells. Importantly, blockade of BCAA/BCAT1 signaling efficiently inhibited leukemogenesis both in vivo and in vitro.
Project description:MET exon 14 skipping mutations (METΔex14) are oncogenic drivers in ~3-5% of lung cancer, which can be targeted with MET tyrosine kinase inhibitors (TKIs). The emergence of resistance limits long-term responses and is commonly mediated by secondary genomic alterations. We devised a preclinical strategy to study MET-TKI resistance using a novel dose escalation approach on METΔex14-dependent cancer cells to generate MET-TKI-refractory isogenic counterparts. Targeted sequencing of resistant clones identified acquired mutations in SPOP and MGA, both antagonists of MYC activity. Further investigation of SPOP and MGA interactomes confirmed MYC as the likeliest target shared between their regulatory networks. SPOP- and MGA-mutant clones exhibited high MYC levels and transcriptomic signatures of MYC activation. Ectopic expression of MYC rescued tumor growth in the presence of TKI, while MYC depletion mimicked the cytotoxic effect of TKI treatment, indicating that MYC activity is coupled to MET signaling and MYC is required to mediate drug resistance. Analysis of a clinical cohort of METΔex14-positive lung cancer revealed several cases where acquired MYC pathway alterations mediated resistance to MET-TKIs. These findings collectively converge on MYC as a key pathway in the progression of MET TKI-resistant cancers, and our in vitro data support the strategy of co-targeting MYC and MET to yield more prolonged responses in patients with METΔex14-positive lung cancer.
Project description:Lung adenocarcinoma cells harboring epidermal growth factor receptor (EGFR) mutations are sensitive to EGFR tyrosine kinase inhibitors (TKIs). Prolonged cancer treatment will induce the development of acquired resistance to EGFR TKI. To gain insight into the molecular mechanisms of EGFR-TKIs resistance, we generate EGFR-TKI-resistant HCC827-8-1 cells to be analyzed by microarray with their parental HCC827cells.