Synergistic actions of Alpelisib and Melatonin in breast cancer cell lines with PIK3CA gene mutation.

AIMS: Breast cancer (BC) presents high mortality rate and about 25-46 % have mutation in the PIK3CA gene. Alpelisib is a PI3K inhibitor that acts on p110α, which is a subunit of the PI3K protein. The melatonin shown important anti-neoplastic effects and may increase the effectiveness of chemotherapy. This study evaluated the synergistic action of Alpelisib and Melatonin in BC lines carrying the H1047R mutation in PIK3CA, relative to the cellular dynamics and the PI3K/AKT/mTOR pathway. MAIN METHODS: MDA-MB-468 (triple-ernegative), MDA-MB-453 (H1047R PIK3CA, HER2+) and T-47D cells (H1047R PIK3CA, ER+/PR+) were divided into four treatment groups: control; Melatonin (1 mM); Alpelisib (1 µM); and Alpelisib (1 µM) + Melatonin (1 mM). Cell viability and migration were investigated using the MTT assay and Transwell assay, respectively. Protein expression of PI3K, p-AKT, mTOR, HIF-1α, and caspase-3, was verified using immunocytochemistry. KEY FINDINGS: MTT assay revealed that MDA-MB-453 and T-47D showed reduction in cell viability in all groups, especially in the MDA-MB-453 treated with Melatonin + Alpelisib. MDA-MB-468 presents reduction in cell migration only with Melatonin, while in the lines with mutation, the treatment of Melatonin + Alpelisib caused inhibition of cell migration. PI3K, p-AKT, mTOR and HIF-1α were inhibited after treatment with Melatonin + Alpelisib in MDA-MB-453 and T-47D lines. The expression of caspase-3 increased in all groups in MDA-MB-453 and T-47D cells, being the increase more pronounced in the Melatonin + Alpelisib group. SIGNIFICANCE: These results indicate that the combined use of Melatonin and Alpelisib may be more effective in inhibiting BC in women carrying the PIK3CA gene mutation than either treatment alone.

HER2-low status and response to neoadjuvant chemotherapy in HER2 negative early breast cancer.

PURPOSE: Knowledge on whether low expressions of HER2 have prognostic impact in early-stage breast cancer (BC) and on its response to current chemotherapy protocols can contribute to medical practice and development of new drugs for this subset of patients, changing treatment paradigms. This study aims to evaluate the impact of HER2-low status on response to neoadjuvant chemotherapy (NACT) and survival outcomes in early-stage HER2-negative BC. METHODS: Records from all BC patients treated with NACT from January 2007 to December 2018 in a single cancer center were retrospectively reviewed. HER2-negative (immunohistochemistry [IHC] 0, + 1, or + 2 non-amplified by in situ hybridization [ISH]) patients were included. HER2-low was defined by IHC + 1 or + 2 ISH non-amplified and HER2-0 by IHC 0. The coprimary objectives were to compare pathological complete response (pCR) and relapse-free survival (RFS) between luminal/HER2-low versus luminal/HER2-0 populations and between triple negative (TNBC)/HER2-low versus TNBC/HER2-0. RESULTS: In total, 855 HER2-negative patients were identified. The median follow-up was 59 months. 542 patients had luminal subtype (63.4%) and 313 had TNBC (36.6%). 285 (33.3%) were HER2-low. Among luminal patients, 145 had HER2 IHC + 1 (26.8%) and 91 had IHC + 2/ISH non-amplified (16.8%). In TNBC, 36 had HER2 IHC + 1 (11.5%) and 13 had IHC + 2/ISH non-amplified (4.2%). Most patients had locally advanced tumors, regardless of subtype or HER2-low status. For luminal disease, pCR was achieved in 13% of HER2-low tumors versus 9.5% of HER2-0 (p = 0.27). Similarly, there was no difference in pCR rates among TNBC: 51% versus 47% in HER2-low versus HER2-0, respectively (p = 0.64). HER2-low was also not prognostic for RFS, with 5-year RFS rates of 72.1% versus 71.7% (p = 0.47) for luminal HER2-low/HER2-0, respectively, and 75.6% versus 70.8% (p = 0.23) for TNBC HER2-low/HER2-0. CONCLUSION: Our data does not support HER2-low as a biologically distinct BC subtype, with no prognostic value on survival outcomes and no predictive effect for pCR after conventional NACT.

Pertuzumab in HER2-positive early breast cancer: current use and perspectives.

Although the prognosis of HER2-positive breast cancer patients has dramatically improved with modern chemotherapy and the monoclonal antibody trastuzumab, up to 31% of them will experience a recurrence in the long term. After the unprecedented benefit in overall survival with the addition of the second monoclonal antibody pertuzumab for patients with metastatic disease, the drug was tested with various degrees of success in the preoperative and postoperative settings. In this review, we will focus on the pharmacologic aspects of the drug, including mechanism of action and toxicities, and discuss clinical data regarding its use in advanced and early stage HER2-positive breast cancer, placing in perspective the pros and cons regarding other available drugs and biomarkers.

Risk of adverse events with the addition of targeted agents to endocrine therapy in patients with hormone receptor-positive metastatic breast cancer: A systematic review and meta-analysis.

BACKGROUND: Combining targeted agents and endocrine therapy (ET) improves outcomes in hormone receptor-positive metastatic breast cancer patients but increases the risk of adverse events (AEs). This meta-analysis aims to estimate the comparative risk of AEs with ET in addition to targeted agents in this setting. METHODS: A systematic literature search of MEDLINE, EMBASE, Cochrane Library and conference proceedings up to July 17th 2017 was conducted to identify randomized controlled trials investigating ET with or without CDK4/6, mTOR, PI3K inhibitors and anti-HER2 agents. We calculated summary risk estimates (odds ratio, OR) and 95% confidence intervals (CI) for each AE within each class of targeted agents for each trial, and pooled analysis using the random and fixed effect models. RESULTS: Sixteen studies (n=8529 patients) were included. The addition of targeted agents to ET was associated with a significant higher risk of grade 3-4 AEs: OR 2.86 (95% CI 2.49-3.27) for CDK4/6 inhibitors, 1.88 (95% CI 1.39-2.53) for mTOR inhibitors, 2.05 (95% CI 1.63-2.58) for PI3K inhibitors, and 2.48 (95% CI 1.09-5.66) for anti-HER2 agents. The highest class-specific risks were neutropenia grade 3-4 for CDK4/6 inhibitors (OR 40.77; 95% CI 19.52-85.19), stomatitis grade 3-4 for mTOR inhibitors (OR 11.92; 95% CI 3.68-38.57), hyperglycemia grade 3-4 for PI3K inhibitors (OR 40.93; 95% CI 10.08-166.22) and diarrhea for anti-HER2 agents (OR 9.93; 95% CI 4.71-20.95). CONCLUSIONS: Adding targeted agents to ET is associated with a significant increased risk of AEs. The risk of developing different AEs varies largely according to the type of agent used.