Glutamine deficiency drives transforming growth factor-ß signaling activation that gives rise to myofibroblastic carcinoma-associated fibroblasts.

Tumor-promoting carcinoma-associated fibroblasts (CAFs), abundant in the mammary tumor microenvironment (TME), maintain transforming growth factor-ß (TGF-ß)-Smad2/3 signaling activation and the myofibroblastic state, the hallmark of activated fibroblasts. How myofibroblastic CAFs (myCAFs) arise in the TME and which epigenetic and metabolic alterations underlie activated fibroblastic phenotypes remain, however, poorly understood. We herein show global histone deacetylation in myCAFs present in tumors to be significantly associated with poorer outcomes in breast cancer patients. As the TME is subject to glutamine (Gln) deficiency, human mammary fibroblasts (HMFs) were cultured in Gln-starved medium. Global histone deacetylation and TGF-ß-Smad2/3 signaling activation are induced in these cells, largely mediated by class I histone deacetylase (HDAC) activity. Additionally, mechanistic/mammalian target of rapamycin complex 1 (mTORC1) signaling is attenuated in Gln-starved HMFs, and mTORC1 inhibition in Gln-supplemented HMFs with rapamycin treatment boosts TGF-ß-Smad2/3 signaling activation. These data indicate that mTORC1 suppression mediates TGF-ß-Smad2/3 signaling activation in Gln-starved HMFs. Global histone deacetylation, class I HDAC activation, and mTORC1 suppression are also observed in cultured human breast CAFs. Class I HDAC inhibition or mTORC1 activation by high-dose Gln supplementation significantly attenuates TGF-ß-Smad2/3 signaling and the myofibroblastic state in these cells. These data indicate class I HDAC activation and mTORC1 suppression to be required for maintenance of myCAF traits. Taken together, these findings indicate that Gln starvation triggers TGF-ß signaling activation in HMFs through class I HDAC activity and mTORC1 suppression, presumably inducing myCAF conversion.

Efficacy of Clinical Guidelines in Identifying All Japanese Patients with Hereditary Breast and Ovarian Cancer.

Clinical screening using the National Comprehensive Cancer Network (NCCN) testing criteria may fail to identify all patients with hereditary breast and ovarian cancers. Thus, this study aimed to evaluate the strategy of expanding target patients for genetic testing among Japanese patients. We reviewed the medical records of 91 breast cancer patients who underwent genetic testing. Among 91 patients, eight were diagnosed with pathogenic or likely pathogenic variants: BRCA1 (n = 4) and BRCA2 (n = 4). Among 50 patients meeting the testing criteria of the guidelines, 6 (12%) were diagnosed with pathogenic or likely pathogenic variants. The sensitivity and specificity of screening using the testing criteria were 75% and 47%, respectively. Expanding the NCCN criteria to include all women diagnosed with breast cancer aged ≤65 years achieved 88% sensitivity but 8% specificity. The expansion of the NCCN criteria could benefit Japanese patients; however, larger studies are necessary to change clinical practice.

Long-term survival analysis of addition of carboplatin to neoadjuvant chemotherapy in HER2-negative breast cancer.

PURPOSE: Addition of carboplatin (CBDCA) to neoadjuvant chemotherapy (NAC) in triple-negative breast cancer (TNBC) has improved pathological complete response (pCR) rates in previous studies. We present long-term survival outcomes (disease-free survival [DFS], pre-planned secondary endpoint; overall survival [OS], post hoc exploratory endpoint) of our randomized study of the addition of CBDCA to NAC for HER2-negative breast cancer. METHODS: Patients with stage II/III, HER2-negative breast cancer (N = 179) were randomly assigned to receive CP-CEF (four 3-week cycles of CBDCA [area under the curve, 5 mg/mL/min, day 1] and weekly paclitaxel [wPTX, 80 mg/m2, day 1, 8, 15] followed by four 3-week cycles of cyclophosphamide, epirubicin, and 5-fluorouracil [CEF, 500/100/500 mg/m2]) or P-CEF (four cycles of wPTX followed by four cycles of CEF) as NAC. DFS and OS were analyzed at each population of pCR status and assigned treatment arm. RESULTS: Of 179 patients, 154 were available for long-term follow-up. At a median follow-up of 6.6 years (range, 0.7-8.0 years), patients who achieved pCR [n = 42, 23.5% (CP-CEF: n = 28, P-CEF: n = 16)] had longer DFS and OS than non-pCR patients [DFS; HR 0.15 (0.04-0.61), P = 0.008, OS; log-rank P = 0.003]. Addition of carboplatin to NAC significantly improved DFS and OS in the subset of patients with TNBC [DFS: HR, 0.22 (0.06-0.82), P = 0.015; OS: HR, 0.12 (0.01-0.96), P = 0.046], but not in the subset of patients with hormone receptor-positive disease or among all patients. CONCLUSIONS: Addition of carboplatin to neoadjuvant chemotherapy significantly improved DFS and OS in patients with TNBC but not in those with hormone receptor-positive, HER2-negative breast cancer.