Project description:Growth factor signaling and angiogenesis may promote endocrine-resistance in breast cancer and blocking these pathways can overcome resistance in preclinical models. We conducted a phase-II study of adding the VEGFR/Ras/Raf/MAPK inhibitor sorafenib to endocrine therapy in metastatic ER-positive breast cancer, either upon progression or after maximal response with measurable residual disease. Tumor biopsies and serum were collected on days 1 and 28. Primary endpoint was response by RECIST after 3 months and secondary endpoints included safety, time to progression (TTP), and biomarker assessment. Planned sample size was 43 patients but the study closed after 11 patients because of slow accrual. 8 patients had progressive disease (PD) on entry and 3 had stable disease (SD). One patient with SD discontinued sorafenib after 2-weeks because of grade 3 rash. Of the 10 remaining patients after adding sorafenib, 7 had SD (70%), 3 had PD (30%) and median TTP was 6.1-months. Of the 8 patients who entered the study with PD on endocrine therapy, 5 converted to SD (62%) with a median TTP of 6.4-months. Notably, patients on tamoxifen had a median TTP of 8.4-months. The most common adverse events were hypophosphatemia, hypokalemia, and rash, and the majority were grade 1&2 with no grade 4 toxicities. There was a significant reduction in serum VEGFR2 and PDGFR-α on day-28 (p-values 0.0035 and 0.017, respectively). Both serum VEGF and sVEGFR-1 were increased on day-28, but the differences were not statistically significant (p-values 0.3223 and 0.084, respectively). Microarray analysis identified 32 suppressed genes with an FDR of <0.20 and at least a 2-fold change with no induced genes and 29 KEGG pathways were enriched on day-28. Our study suggests that sorafenib can restore endocrine sensitivity, particularly tamoxifen, and this strategy of adding novel agents in patients progressing on endocrine therapy should be examined in future trials. This was a single-institution, phase II study of adding sorafenib to existing endocrine therapy. On study entry, eligible patients underwent serum sample collection and core biopsy of accessible disease (if applicable) on endocrine therapy and prior to starting sorafenib. Serum and a second biopsy were then collected on day 28. Sorafenib dose was 400mg orally twice daily along with continuing the same endocrine agent. Patients were followed monthly for clinical and toxicity evaluation. Disease response by RECIST criteria was assessed after 3 months by appropriate scans and these were obtained every 2 months thereafter until progression. Sorafenib and the endocrine agent were continued until disease progression or unacceptable toxicity
Project description:Growth factor signaling and angiogenesis may promote endocrine-resistance in breast cancer and blocking these pathways can overcome resistance in preclinical models. We conducted a phase-II study of adding the VEGFR/Ras/Raf/MAPK inhibitor sorafenib to endocrine therapy in metastatic ER-positive breast cancer, either upon progression or after maximal response with measurable residual disease. Tumor biopsies and serum were collected on days 1 and 28. Primary endpoint was response by RECIST after 3 months and secondary endpoints included safety, time to progression (TTP), and biomarker assessment. Planned sample size was 43 patients but the study closed after 11 patients because of slow accrual. 8 patients had progressive disease (PD) on entry and 3 had stable disease (SD). One patient with SD discontinued sorafenib after 2-weeks because of grade 3 rash. Of the 10 remaining patients after adding sorafenib, 7 had SD (70%), 3 had PD (30%) and median TTP was 6.1-months. Of the 8 patients who entered the study with PD on endocrine therapy, 5 converted to SD (62%) with a median TTP of 6.4-months. Notably, patients on tamoxifen had a median TTP of 8.4-months. The most common adverse events were hypophosphatemia, hypokalemia, and rash, and the majority were grade 1&2 with no grade 4 toxicities. There was a significant reduction in serum VEGFR2 and PDGFR-α on day-28 (p-values 0.0035 and 0.017, respectively). Both serum VEGF and sVEGFR-1 were increased on day-28, but the differences were not statistically significant (p-values 0.3223 and 0.084, respectively). Microarray analysis identified 32 suppressed genes with an FDR of <0.20 and at least a 2-fold change with no induced genes and 29 KEGG pathways were enriched on day-28. Our study suggests that sorafenib can restore endocrine sensitivity, particularly tamoxifen, and this strategy of adding novel agents in patients progressing on endocrine therapy should be examined in future trials.
Project description:Here we characterise the response of models of ER-positive breast cancer to treatment with the small molecule MDM2 inhibitor NVP-CGM097, a dihydroisoquinolinone derivative currently evaluated in a phase I clinical trial. We show that NVP-CGM097 reduces tumour cell viability of in vitro and in vivo models of endocrine sensitive, endocrine resistant and palbociclib (CDK4/6 inhibitor) resistant p53 wildtype (p53wt) ER-positive breast cancer. NVP-CGM097 synergises with both fulvestrant and palbociclib in models of therapy resistance. Importantly, we identify the key mechanisms of the synergistic interactions between NVP-CGM097 and endocrine therapy, which occurs through the inhibition of E2F Targets and G2M Checkpoint signalling and induction of senescence, rather than depending upon upregulation of p53 dependent apoptotic pathways. Moreover, we find these same pathways are synergistically targeted during the combination treatment of ER positive breast cancer models with NVP-CGM097 and palbociclib. This indicates the genuine potential of MDM2 inhibition as therapy in advanced ER-positive breast cancer as combination endocrine therapy and CDK4/6 inhibitor treatment becomes embedded as standard of care.
Project description:The ESR1 ligand binding domain activating mutations are the most prevalent genetic mechanism of acquired endocrine resistance in metastatic hormone receptor-positive breast cancer. These mutations confer endocrine resistance that remains estrogen receptor (ER) dependent. We hypothesized that in the presence of the ER mutations, continued ER blockade with endocrine therapies that target mutant ER is essential for tumor suppression even with chemotherapy treatment. Here, we conducted comprehensive pre-clinical in vitro and in vivo experiments testing the efficacy of adding fulvestrant to fluorouracil (5FU) and the 5FU pro-drug, capecitabine, in models of wild-type (WT) and mutant ER. Our findings revealed that while this combination had an additive effect in the presence of WT-ER, in the presence of the Y537S ER mutation there was synergy. Notably, these effects were not seen with the combination of 5FU and selective estrogen receptor modulators, such as tamoxifen, or in the absence of intact P53. Likewise, in a patient derived xenograft (PDX) harboring a Y537S ER mutation the addition of fulvestrant to capecitabine potentiated tumor suppression. Moreover, multiplex immunofluorescence revealed that this effect was due to decreased cell proliferation in all cells expressing ER and was not dependent on the degree of ER expression. Taken together, these results support the clinical investigation of the combination of ER antagonists with capecitabine in patients with metastatic hormone receptor-positive breast cancer who have experienced progression on endocrine therapy and targeted therapies, particularly in the presence of an ESR1 activating mutation.
Project description:Resistance to endocrine treatments and CDK4/6 inhibitors is considered a near-inevitability in most patients with estrogen receptor positive breast cancers (ER + BC). By genomic and metabolomics analyses of patients' tumours, metastasis-derived patient-derived xenografts (PDX) and isogenic cell lines we demonstrate that a fraction of metastatic ER + BC is highly reliant on oxidative phosphorylation (OXPHOS). Treatment by the OXPHOS inhibitor IACS-010759 strongly inhibits tumour growth in multiple endocrine and palbociclib resistant PDX. Mutations in the PIK3CA/AKT1 genes are significantly associated with response to IACS-010759. At the metabolic level, in vivo response to IACS-010759 is associated with decreased levels of metabolites of the glutathione, glycogen and pentose phosphate pathways in treated tumours. In vitro, endocrine and palbociclib resistant cells show increased OXPHOS dependency and increased ROS levels upon IACS-010759 treatment. Finally, in ER + BC patients, high expression of OXPHOS associated genes predict poor prognosis. In conclusion, these results identify OXPHOS as a promising target for treatment resistant ER + BC patients.
Project description:Advanced breast cancer is characterised by enhanced tumour adaptability to therapeutic pressure and the metastatic microenvironment. Transcriptome differences in three ER positive (ER+) cell models are uncovered through this RNA-seq analysis of MCF7 (endocrine sensitive), LY2 (endocrine resistant) and T347 (derived from an ER-positive, treatment resistant brain metastatic patient tumour) cells.
Project description:In breast cancer models, combination epigenetic therapy with a DNA methyltransferase inhibitor and a histone deacetylase inhibitor led to reexpression of genes encoding important therapeutic targets, including the estrogen receptor (ER). We conducted a multicenter phase II study of 5-azacitidine and entinostat in women with advanced hormone-resistant or triple-negative breast cancer (TNBC). Purpose: In breast cancer models, combination epigenetic therapy with a DNA methyltransferase inhibitor and a histone deacetylase inhibitor led to re-expression of genes encoding important therapeutic targets including the estrogen receptor (ER). We conducted a multicenter phase II study of 5-azacitidine (AZA) and entinostat in women with advanced hormone-resistant or triple-negative breast cancer (TNBC). Patients and Methods: Patients received AZA 40 mg/m2 (days 1-5, 8-10) and entinostat 7 mg (days 3,10) of 28 day cycle. Continuation of epigenetic therapy was offered with addition of endocrine therapy at time of progression (optional continuation, OC phase). Primary endpoint was objective response rate (ORR) in each cohort. We hypothesized that ORR would be >20% against null of 5% using Simon two-stage design. At least 1 response was required in 1st of 13 patients per cohort to continue accrual to 27 per cohort. Type I error 4%, power 90%. Results: There was one partial response among 27 women with hormone-resistant disease (ORR=4%, 95% CI=0-19%), and none in 13 women with TNBC. One additional partial response was observed in the OC phase in the hormone-resistant cohort (n=12). Mandatory tumor samples were obtained pre- and post-treatment (58% paired) with either up- or down-regulation of ER observed in approximately 50% of post-treatment biopsies in the hormone-resistant, but not TNBC cohort. Conclusion: Combination epigenetic therapy was well tolerated but our primary endpoint was not met. OC phase results suggest that some women benefit from epigenetic therapy and/or reintroduction of endocrine therapy beyond progression but further study is needed.
Project description:Activation of the PI3K pathway in estrogen receptor α (ER)-positive (+) breast cancer is associated with reduced ER expression and activity, luminal B subtype, and poor outcome. PTEN is a negative regulator of the PI3K pathway typically lost in ER-negative (-) breast cancer. To clarify the effect of PTEN down-regulation on the response of ER+/HER2- breast cancer to endocrine therapy, we established reduced PTEN cell models using inducible knockdown. We found that only moderate PTEN reduction is sufficient to enhance PI3K signaling, generate a gene signature associated with luminal B subtype, and cause endocrine resistance. Combining endocrine therapy with mTOR, AKT, or MEK inhibitors improves antitumor activity, but the efficacy varies by type of endocrine therapy and the specific inhibitor. Fulvestrant plus an AKT inhibitor is the most potent combination when PTEN is reduced, inducing apoptosis and tumor regression. This combination deserves further study in patients with PI3K pathway activation.
Project description:Advanced breast cancer is characterised by enhanced tumour adaptability to therapeutic pressure and the metastatic microenvironment. Targeting epi-transcriptomic modulators may reverse cellular adaptability, offering new therapeutic strategies to treat metastatic disease. This study looks into the dynamic adaptations that occur in cancer cells in response to therapeutic pressure and metastatic evolution by profiling mRNA epi-transcriptomic modifications in models of disease progression. ER positive (ER+) cell models were used to represent progressive breast cancer, MCF7 (endocrine sensitive), LY2 (endocrine resistant) and T347 (derived from an ER-positive, treatment resistant brain metastatic patient tumour) cells. MeRIP sequencing was undertaken to determine genome-wide RNA methylated regions.
Project description:The NEWEST (Neoadjuvant Endocrine Therapy for Women with Estrogen-Sensitive Tumours) trial compared the clinical and biological activity of fulvestrant 500 mg vs 250 mg in the neoadjuvant setting. In this multi-centre phase II study, post-menopausal women with operable, locally advanced (T2, 3, 4b; N0-3; M0) ER-positive breast tumours were randomised to receive neoadjuvant treatment with either dose of fulvestrant for 16 weeks before surgery. Tumour core biopsies were obtained at baseline, 4 weeks and at surgery for assessment of changes in biomarker expression. Tumour volumes were measured by 3-D ultrasound at the same timepoints. In this trial, the percentage of patients who showed a reduction in tumour volume or stabilisation of disease (using RECIST criteria) after treatment with fulvestrant 500 mg was 36% (26 out of 69 patients). Therefore, within a population of endocrine-therapy naive patients whose tumours were confirmed as being ER-positive at the time of study entry, there is a subgroup who gained particular clinical benefit from fulvestrant treatment. These clinical response data together with the availability of biological response information and frozen tumour tissue from participants makes the NEWEST trial an attractive setting in which to investigate the potential of new markers of response to fulvestrant. 42 samples