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Affymetrix SNP array data for mammary tumors that recurred after inactivation of the oncogenic PIK3CA-H1047R

ABSTRACT: Gain-of-function mutation of PIK3CA represents one of the most common oncogenic events in human malignancy, making PI3K an attractive target for cancer therapy. Despite the great promise of targeted therapy, drug resistance is likely to develop, causing treatment failure. To elucidate resistance mechanisms to PI3K-targeted therapy, we constructed a mouse model of breast cancer conditionally expressing PIK3CA-H1047R. Surprisingly, the majority of mammary tumors induced by PIK3CA-H1047R expression recurred following PIK3CA-H1047R inactivation. Genomic analyses of recurrent tumors revealed multiple lesions, including spontaneous focal amplification of c-Met or c-Myc. While amplification of c-Met allowed tumor survival dependent on activation of endogenous PI3K, tumors with amplification of c-Myc become independent of the PI3K pathway. Functional analyses further demonstrated that c-Myc contributed to tumors’ independence of oncogene and resistance to PI3K inhibition. Together, our data suggest that MYC elevation in tumors may be a potential mechanism conferring resistance to current PI3K-targeted therapies.

ORGANISM(S): Mus musculus

PROVIDER: GSE27691 | GEO | 2011/08/02

SECONDARY ACCESSION(S): PRJNA138147

REPOSITORIES: GEO

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Affymetrix SNP array data for mammary tumors that recurred after inactivation of the oncogenic PIK3CA-H1047R

Project description:Gain-of-function mutation of PIK3CA represents one of the most common oncogenic events in human malignancy, making PI3K an attractive target for cancer therapy. Despite the great promise of targeted therapy, drug resistance is likely to develop, causing treatment failure. To elucidate resistance mechanisms to PI3K-targeted therapy, we constructed a mouse model of breast cancer conditionally expressing PIK3CA-H1047R. Surprisingly, the majority of mammary tumors induced by PIK3CA-H1047R expression recurred following PIK3CA-H1047R inactivation. Genomic analyses of recurrent tumors revealed multiple lesions, including spontaneous focal amplification of c-Met or c-Myc. While amplification of c-Met allowed tumor survival dependent on activation of endogenous PI3K, tumors with amplification of c-Myc become independent of the PI3K pathway. Functional analyses further demonstrated that c-Myc contributed to tumors’ independence of oncogene and resistance to PI3K inhibition. Together, our data suggest that MYC elevation in tumors may be a potential mechanism conferring resistance to current PI3K-targeted therapies. Affymetrix SNP array analysis was performed with Mouse Diversity Genotyping Arrays (Affymetrix) on genomic DNA extracted from frozen biopsies of 6 recurrent mouse mammary tumor samples. Copy number analysis was performed for the mouse mammary tumors using genomic DNA from normal mammary tissue as the reference for copy number inference.

2011-08-01 | E-GEOD-27691 | biostudies-arrayexpress

Ito2019 - gefitnib resistance of lung adenocarcinoma caused by MET amplification

Project description:The model is based on publication: Mathematical analysis of gefitinib resistance of lung adenocarcinoma caused by MET amplification Abstract: Gefitinib, one of the tyrosine kinase inhibitors of epidermal growth factor receptor (EGFR), is effective for treating lung adenocarcinoma harboring EGFR mutation; but later, most cases acquire a resistance to gefitinib. One of the mechanisms conferring gefitinib resistance to lung adenocarcinoma is the amplification of the MET gene, which is observed in 5–22% of gefitinib-resistant tumors. A previous study suggested that MET amplification could cause gefitinib resistance by driving ErbB3-dependent activation of the PI3K pathway. In this study, we built a mathematical model of gefitinib resistance caused by MET amplification using lung adenocarcinoma HCC827-GR (gefitinib resistant) cells. The molecular reactions involved in gefitinib resistance consisted of dimerization and phosphorylation of three molecules, EGFR, ErbB3, and MET were described by a series of ordinary differential equations. To perform a computer simulation, we quantified each molecule on the cell surface using flow cytometry and estimated unknown parameters by dimensional analysis. Our simulation showed that the number of active ErbB3 molecules is around a hundred-fold smaller than that of active MET molecules. Limited contribution of ErbB3 in gefitinib resistance by MET amplification is also demonstrated using HCC827-GR cells in culture experiments. Our mathematical model provides a quantitative understanding of the molecular reactions underlying drug resistance.

2019-09-30 | BIOMD0000000827 | BioModels

MYC is a clinically significant determinant of mTOR inhibitor resistance in breast cancer

Project description:Targeting the PI3K-AKT-mTOR pathway is a promising therapeutic strategy for breast cancer treatment. However, low response rates and the development of acquired resistance to PI3K-AKT-mTOR inhibitors remain major challenges for successful patient treatment. Here, we show that MYC activation is a central and clinically relevant mechanism of resistance to mTOR inhibitors (mTORi) in breast cancer. Multi-omic profiling of mouse invasive lobular carcinoma (ILC) tumors revealed recurrent focal Myc amplification in tumors that acquire resistance to the mTORi AZD8055. The gained MYC activity was significantly associated with biological processes linked to mTORi response. Specifically, MYC counteracted the translation inhibitory effect induced by mTORi by promoting the translation of ribosomal proteins. In vitro and in vivo induction of MYC conferred resistance to AZD8055 as well as the clinically approved mTORi everolimus, both in mouse models of ILC and human breast cancer models. Conversely, AZD8055-resistant ILC cells depended on MYC, as demonstrated by synergistic growth inhibition using mTORi and MYCi combination treatment. Notably, MYC status was significantly associated with poor response to everolimus therapy in metastatic breast cancer patients. Thus, MYC is a clinically relevant determinant of mTORi resistance that may guide the selection of breast cancer patients for mTOR targeted therapies.

2023-05-02 | PXD041927 | Pride

Potent antitumor activity of Cabozantinib, a c-MET and VEGFR2 Inhibitor, in a Colorectal Cancer Patient-derived Tumor Explant Model

Project description:Anti-angiogenic therapy is commonly used for the treatment of CRC. Although patients derive some clinical benefit, treatment resistance inevitably occurs. The MET signaling pathway has been proposed to be a major contributor of resistance to anti-angiogenic therapy. MET is upregulated in response to VEGF pathway inhibition and plays an essential role in tumorigenesis and progression of tumors. In this study we set out to determine the efficacy of cabozantinib in a preclinical CRC PDTX model. We demonstrate potent inhibitory effects on tumor growth in 80% of tumors treated. The greatest antitumor effects were observed in tumors that possess a mutation in the PIK3CA gene. The underlying antitumor mechanisms of cabozantinib consisted of inhibition of angiogenesis and Akt activation and significantly decreased expression of genes involved in the PI3K pathway. These findings support further evaluation of cabozantinib in patients with CRC. PIK3CA mutation as a predictive biomarker of sensitivity is intriguing and warrants further elucidation. A clinical trial of cabozantinib in refractory metastatic CRC is being activated. CRC PDTX Model treated with cabozantinib

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Endogenous expression of an oncogenic PI3K mutation leads to activated PI3K pathway signaling and an invasive phenotype

Project description:The PTEN/PI3K pathway is commonly mutated in cancer and therefore represents a rational target for therapeutic intervention. In order to investigate the primary phenotype(s) mediated by mutant PIK3CA in a clean and highly patient-relevant context, we utilized a non-tumorigenic MCF10A parental and isogenic knock-in cell line that harbors a common activating PIK3CA kinase domain mutation (H1047R). We found that introduction of an endogenously mutated PIK3CA primarily results in a marked epithelial-mesenchymal transition (EMT) and invasive phenotype compared to isogenic wild-type cells. Moreover, a potent and selective inhibitor of PIK3CA (GDC-0941) was highly effective and selective on reversing this phenotype compared to cell-proliferation, highlighting a potential new paradigm for studying PI3K-pathway targeted agents. Keywords: Expression Array Gene expression profiles from a parental MCF10A breast line and an MCF10A clone that has a PI3K activating mutation (H1047R) knocked-in. We plated the cells in 10cm dishes overnight in media with serum, but lacking EGF or insulin. DMSO or GDC-0941 (PI3K inhibitor) at an EC50 concentration were added to triplicate plates of cells in the morning. After 4 hours the RNA was harvested using the Qiagen RNeasy kit. There are 12 samples total.

2011-08-09 | E-GEOD-17785 | biostudies-arrayexpress

Mutant PI3K cooperates with HER2 to promote mammary tumor formation and induces trastuzumab resistance in vivo

Project description:HER2 (ERBB2) gene amplification and PIK3CA mutations often co-occur in breast cancer, and aberrant activation of the PI3K pathway has been implicated in resistance to HER2-directed therapies. We have created a mouse model of HER2-overexpressing (HER2+), PIK3CAH1047R-mutant breast cancer. Mice expressing both human HER2 and mutant PIK3CA in their mammary glands developed tumors with a significantly shorter latency compared to mice expressing either oncogene alone. By microarray analysis, HER2-driven tumors clustered with the luminal subtype, whereas HER2+PIK3CA and PIK3CA-driven tumors were associated with the claudin-low breast cancer subtype. In accordance, PIK3CA and HER2+PIK3CA tumors expressed elevated levels of EMT and stem cell markers, and cells from HER2+PIK3CA tumors more efficiently formed mammospheres, providing further evidence that activated PIK3CA may enrich for cancer stem cells. Finally, HER2+PIK3CA tumors are resistant to the HER2 antibody trastuzumab; resistance is partially reversed by the addition of a PI3K inhibitor. Taken together, these studies suggest that the co-expression of HER2 and PI3KH1047R in the mouse mammary gland accelerates the formation of aggressive, trastuzumab-resistant tumors. referenceXsample

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The evolution of MET and NRAS gene amplification as sequential acquired resistance mechanisms in a patient with EGFR mutation positive non-small cell lung cancer

Project description:EGFR mutant non-small cell lung cancer patients disease demonstrates remarkable responses to EGFR targeted therapy, but inevitably they succumb to acquired resistance, which can be complex and difficult to treat. Analyzing acquired resistance through broad molecular testing is crucial to understanding the resistance mechanisms and developing new treatment options. We performed diverse clinical testing on a patient with successive stages of acquired resistance, first to an EGFR inhibitor with MET gene amplification and then subsequently to combination EGFR and MET targeted therapies. A patient-derived cell line obtained at the time of disease progression was used to identify NRAS gene amplification as an additional driver of drug resistance to combination EGFR/MET therapies. Analysis of downstream signaling revealed ERK activation that could only be eliminated by trametinib treatment, while Akt activation could be modulated by various combinations of MET, EGFR and PI3K inhibitors. Combination of an EGFR inhibitor with a MEK inhibitor was identified as a possible treatment option to overcome drug resistance related to NRAS gene amplification.

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High-dose oncogenic PIK3CA drives constitutive cellular stemness through increased NODAL/TGFb signaling

Project description:Oncogenic PIK3CA mutations activate phosphoinositide 3-kinase (PI3K) and are among the commonest somatic mutations in cancer and mosaic, developmental overgrowth disorders. We recently demonstrated that the ‘hotspot’ variant PIK3CAH1047R exerts striking allele dose-dependent effects on stemness in human induced pluripotent stem cells (iPSCs), and moreover demonstrated multiple oncogenic PIK3CA copies in a substantial subset of human cancers. To identify the molecular mechanism underpinning PIK3CAH1047R allele dose-dependent stemness, we profiled isogenic wild-type, PIK3CAWT/H1047R and PIK3CAH1047R/H1047R iPSCs by high-depth transcriptomics, proteomics and reverse-phase protein arrays (RPPA). PIK3CAH1047R/H1047R iPSCs exhibited altered expression of 5644 genes and 248 proteins, whereas heterozygous hPSCs showed 492 and 54 differentially-expressed genes and proteins, respectively, confirming a nearly deterministic phenotypic effect of homozygosity for PIK3CAH1047R. Pathway and network-based analyses predicted a strong association between self-sustained TGFb/NODAL signaling and the ‘locked’ stemness phenotype induced by homozygosity for PIK3CAH1047R. This stemness gene signature was maintained without exogenous NODAL in PIK3CAH1047R/H1047R iPSCs and was reversed by pharmacological inhibition of TGFb/NODAL signaling but not by PIK3CA-specific inhibition. Analysis of PIK3CA-associated human breast cancers revealed increased expression of the stemness markers NODAL and POU5F1 as a function of disease stage and PIK3CAH1047R allele dosage. Together with emerging realization of the link between NODAL re-expression and aggressive cancer behavior, our data suggest that TGFb/NODAL inhibitors warrant testing in advanced breast tumors with multiple oncogenic PIK3CA copies.

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Mutant PI3K cooperates with HER2 to promote mammary tumor formation and induces trastuzumab resistance in vivo

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