Project description:BRCA mutational status shapes the stromal microenvironment of pancreatic cancer linking CLU+ CAF expression with HSF1 signaling (KPC)
Project description:BRCA mutational status shapes the stromal microenvironment of pancreatic cancer linking CLU+ CAF expression with HSF1 signaling (CAF)
Project description:BRCA mutational status shapes the stromal microenvironment of pancreatic cancer linking CLU+ CAF expression with HSF1 signaling (PSC)
Project description:Cancer-associated fibroblasts (CAFs) give rise to desmoplastic stroma, which supports tumor progression and metastasis, and comprises up to 90% of the tumor mass in pancreatic cancer. Recent work by us and others has shown that CAFs are transcriptionally rewired by adjacent cancer cells to form heterogeneous subtypes. Whether this rewiring is differentially affected by different driver mutations in cancer cells is largely unknown. Here we address this question by dissecting and comparing the stromal landscape of BRCA-mutated and BRCA Wild-type (WT) pancreatic ductal adenocarcinoma (PDAC). We comprehensively analyze PDAC samples from a cohort of 42 patients by laser-capture microdissection, RNA-sequencing and multiplexed immunofluorescence, revealing different CAF subtype compositions in germline BRCA-mutated vs. BRCA-WT tumors. In particular, we detect an increase in a subset of Clusterin (CLU)-positive CAFs in BRCA-mutated tumors. Using cancer organoids, co-cultures and in-vivo models we show that loss of BRCA function in cancer cells leads to a transcriptional shift of pancreatic stellate cells from myofibroblastic into immune-regulatory CLU+ CAFs. This process is mediated through activation of heat-shock factor 1 (HSF1), the transcriptional regulator of Clu. Our findings unravel a new dimension of stromal heterogeneity, influenced by germline mutations in cancer cells, with direct translational implications for clinical research.
Project description:Cancer-associated fibroblasts (CAFs) give rise to desmoplastic stroma, which supports tumor progression and metastasis, and comprises up to 90% of the tumor mass in pancreatic cancer. Recent work by us and others has shown that CAFs are transcriptionally rewired by adjacent cancer cells to form heterogeneous subtypes. Whether this rewiring is differentially affected by different driver mutations in cancer cells is largely unknown. Here we address this question by dissecting and comparing the stromal landscape of BRCA-mutated and BRCA Wild-type (WT) pancreatic ductal adenocarcinoma (PDAC). We comprehensively analyze PDAC samples from a cohort of 42 patients by laser-capture microdissection, RNA-sequencing and multiplexed immunofluorescence, revealing different CAF subtype compositions in germline BRCA-mutated vs. BRCA-WT tumors. In particular, we detect an increase in a subset of Clusterin (CLU)-positive CAFs in BRCA-mutated tumors. Using cancer organoids, co-cultures and in-vivo models we show that loss of BRCA function in cancer cells leads to a transcriptional shift of pancreatic stellate cells from myofibroblastic into immune-regulatory CLU+ CAFs. This process is mediated through activation of heat-shock factor 1 (HSF1), the transcriptional regulator of Clu. Our findings unravel a new dimension of stromal heterogeneity, influenced by germline mutations in cancer cells, with direct translational implications for clinical research.
Project description:Cancer-associated fibroblasts (CAFs) give rise to desmoplastic stroma, which supports tumor progression and metastasis, and comprises up to 90% of the tumor mass in pancreatic cancer. Recent work by us and others has shown that CAFs are transcriptionally rewired by adjacent cancer cells to form heterogeneous subtypes. Whether this rewiring is differentially affected by different driver mutations in cancer cells is largely unknown. Here we address this question by dissecting and comparing the stromal landscape of BRCA-mutated and BRCA Wild-type (WT) pancreatic ductal adenocarcinoma (PDAC). We comprehensively analyze PDAC samples from a cohort of 42 patients by laser-capture microdissection, RNA-sequencing and multiplexed immunofluorescence, revealing different CAF subtype compositions in germline BRCA-mutated vs. BRCA-WT tumors. In particular, we detect an increase in a subset of Clusterin (CLU)-positive CAFs in BRCA-mutated tumors. Using cancer organoids, co-cultures and in-vivo models we show that loss of BRCA function in cancer cells leads to a transcriptional shift of pancreatic stellate cells from myofibroblastic into immune-regulatory CLU+ CAFs. This process is mediated through activation of heat-shock factor 1 (HSF1), the transcriptional regulator of Clu. Our findings unravel a new dimension of stromal heterogeneity, influenced by germline mutations in cancer cells, with direct translational implications for clinical research.
Project description:Purpose:Triple negative breast cancer (TNBC) commonly metastasizes to the brain and predicts poor prognosis with limited therapeutic options. TNBC frequently harbors BRCA mutations translating to platinum sensitivity; platinum response may be augmented by additional suppression of DNA repair mechanisms through poly(ADP-ribose)polymerase (PARP) inhibition. We evaluated brain penetrance and efficacy of Carboplatin +/- the PARP inhibitor ABT888, and investigated gene expression changes in murine intracranial (IC) TNBC models stratified by BRCA and molecular subtype status. Experimental design:Athymic mice were inoculated intra-cerebrally with BRCA-mutant: SUM149 (basal), MDA-MB-436 (claudin-low), or BRCA-wild-type: MDA-MB-468 (basal), MDA-MB-231BR (claudin-low) TNBC cells and treated with PBS control (IP, weekly), Carboplatin (50mg/kg/week, IP), ABT888 (25mg/kg/day, OG), or their combination. DNA-damage (?-H2AX) and apoptosis (cleaved-Caspase-3(cC3)) were assessed via IHC of IC tumors. Gene expression of BRCA-mutant IC tumors was measured. Results: Carboplatin+/-ABT888 significantly improved survival in BRCA-mutant IC models compared to control, but did not improve survival in BRCA-wild-type IC models. Carboplatin+ABT888 revealed a modest survival advantage versus Carboplatin in BRCA-mutant models. ABT888 yielded a marginal survival benefit in the MDA-MB-436 but not in the SUM149 model. BRCA-mutant SUM149 expression of ?-H2AX and cC3 proteins was elevated in all treatment groups compared to Control, while BRCA-wild-type MDA-MB-468 cC3 expression did not increase with treatment. Carboplatin treatment induced common gene expression changes in BRCA-mutant models.Conclusions: Carboplatin+/-ABT888 improves survival in BRCA-mutant IC TNBC models with corresponding DNA damage and gene expression changes. Combination therapy represents a promising treatment strategy for patients with TNBC brain metastases warranting further clinical investigation. reference x sample
Project description:PARP inhibition has been approved as a compelling strategy for treating multiple human cancers bearing homologous recombination defects (HRD). However, due to the lack of functional biomarkers of PARPi response beyond known genetic mutations in HRD genes, expanding the potential benefit of PARP inhibitors, as well as the identification of effective therapeutic strategies for treating PARPi-resistant cancers remain urgent unmet needs. Here, we report high levels of FoxO1, either at basal expression or upon induction by PARPi, render both BRCA-proficient (BP) and BRCA-deficient (BD) human cancers resistant to PAPRi via modulating transcriptomic signature regulating DNA damage response (DDR). We further elucidated that PARPi-induced STAT3 activation, which occurred through its attenuated dephosphorylation at Y705, resulted in enhanced FoxO1 transcription via recruiting TOP2A, a downstream target of FoxO1. TOP2A orchestrated STAT3-dependent transcriptional program via facilitating RNA Pol II recruitment to gene promoters, as well as promoter-proximal pausing and pause release. Intriguingly, STAT3 inhibitor exhibits a potent synergistic effect with PARPi in treating BP or BD PAPRi-resistant PDX models across cancer types. Our data highlight a potential role of FoxO1 serving as both predictive and prognostic marker for PARPi treatment, and reveal the potency of combination treatment strategy using STAT3 inhibitor with PARPi in sensitizing PARPi-resistant cancers, regardless of BRCA status.