Triple negative breast cancer: Key role of Tumor-Associated Macrophages in regulating the activity of anti-PD-1/PD-L1 agents.

Triple-negative breast cancer (TNBC) is associated with a poor prognosis, due to its aggressive behaviour and lack of effective targeted therapies. Immunocheckpoint inhibitors, such as anti-programmed cell death 1 (PD-1) and anti-PD-ligand(L)1 agents, are in course of investigation in TNBC, used alone or in combination with other systemic or local approaches. However, the high cost of these drugs and the lack of validated predictive biomarkers support the development of strategies aimed to overcome resistance and optimize the efficacy of these approaches. Tumor-Associated Macrophages (TAMs) derive from peripheral blood monocytes recruited into the TNBC microenvironment and, in response to several stimuli, undergo M1 (classical) or M2 (alternative) activation. In TNBC, TAMs promote tumor growth and progression by several mechanisms that include the secretion of inhibitory cytokines, the reduction of effector functions of Tumor Infiltrating Lymphocytes (TILs) and the promotion of Regulatory T cell (Treg). Interestingly, TAMs have been shown to directly and indirectly modulate PD-1/PD-L1 expression in tumor environment. On this scenario, several TAM-centered strategies have been proposed, such as the suppression of TAM recruitment, the depletion of their number, the switch of M2 TAMs into antitumor M1 phenotype and the inhibition of TAM-associated molecules. In this review, we will illustrate the activity of TAMs and associated molecules in TNBC, focusing on their role in modulating the expression of PD-1/PD-L1 and on the emerging TAM-tailored strategies for TNBC patients.

Effects of Eribulin on the RNA Content of Extracellular Vesicles Released by Metastatic Breast Cancer Cells.

Extracellular vesicles (EVs) are small lipid particles secreted by almost all human cells into the extracellular space. They perform the essential function of cell-to-cell communication, and their role in promoting breast cancer progression has been well demonstrated. It is known that EVs released by triple-negative and highly aggressive MDA-MB-231 breast cancer cells treated with paclitaxel, a microtubule-targeting agent (MTA), promoted chemoresistance in EV-recipient cells. Here, we studied the RNA content of EVs produced by the same MDA-MB-231 breast cancer cells treated with another MTA, eribulin mesylate. In particular, we analyzed the expression of different RNA species, including mRNAs, lncRNAs, miRNAs, snoRNAs, piRNAs and tRNA fragments by RNA-seq. Then, we performed differential expression analysis, weighted gene co-expression network analysis (WGCNA), functional enrichment analysis, and miRNA-target identification. Our findings demonstrate the possible involvement of EVs from eribulin-treated cells in the spread of chemoresistance, prompting the design of strategies that selectively target tumor EVs.

Eribulin in cutaneous breast cancer metastasis treatment: clinical activity and symptom control.

AIM: This observational study evaluated the behavior and outcome of cutaneous breast cancer metastasis treated with eribulin. PATIENTS & METHODS: From November 2012 to January 2013, oncologists completed a database with patient, tumor and treatment characteristics from 14 Italian cancer centers. Skin lesions were assessed by Response Evaluation Criteria In Solid Tumors and cutaneous symptoms by present/absent criteria. RESULTS: A total of 23 metastatic breast cancer patients with skin metastasis who were treated with eribulin were analyzed. After treatment, 43% of patients exhibited a partial response, 35% stable disease and 22% progressive disease. Regarding only the skin response, 26% obtained a complete response, 22% a partial response, 39% stable disease and 13% progressive disease. We found an improvement in symptoms, infiltration and ulceration. With a median follow-up of 6 months, median progression-free survival was 4.3 months and median overall survival was 9.1 months. CONCLUSION: The response rate of skin metastasis to eribulin treatment was coherent with systemic responses. The good clinical response in most patients reflected symptom improvement.

Different Cardiotoxicity of Palbociclib and Ribociclib in Breast Cancer: Gene Expression and Pharmacological Data Analyses, Biological Basis, and Therapeutic Implications.

Breast cancer is the most frequent tumor in women. The recent advent of cyclin-dependent kinase (CDK) 4/6 inhibitors palbociclib and ribociclib has represented a major step forward for patients with hormone receptor-positive breast cancer. These two agents have showed similar efficacy in terms of breast cancer outcome but different cardiotoxic effects. In particular, ribociclib, but not palbociclib, has been associated with QT interval prolongation, and the mechanisms underlying this event are still unclear. In order to clarify such difference, we matched the candidate genes associated with QT interval prolongation with genes whose expression is altered following palbociclib or ribociclib treatment. We also investigated whether pharmacokinetic and pharmacodynamic characteristics, such as IC50 (hERG) [concentration of drug producing 50% inhibition (human ether-à-go-go related gene)] and maximum concentration (Cmax), could justify the different effects on QT interval prolongation. Our results show that ribociclib, but not palbociclib, could act by down-regulating the expression of KCNH2 (encoding for potassium channel hERG) and up-regulating SCN5A and SNTA1 (encoding for sodium channels Nav1.5 and syntrophin-α1, respectively), three genes associated with long QT syndrome. Consistent with the cardiotoxicity induced by ribociclib, its IC50 (hERG)/free concentration (Cmax free) ratio is closer to the safety threshold than that of palbociclib. In summary, we hypothesize that the different cardiotoxicity associated with ribociclib and palbociclib could be due to the alteration of potassium and sodium channels induced by ribociclib. A better comprehension of the mechanisms of cardiac channelopathies and drug-induced QT interval prolongation will be fundamental to avoid serious and potentially lethal adverse events and, as a consequence, optimize the management of breast cancer patients.

Elderly patients with advanced colorectal cancer: tolerability and activity of chemotherapy.

AIMS AND BACKGROUND: Colorectal cancer is the most common gastrointestinal tumor in Western countries and is increasing in elderly patients. In recent years, new treatments based on the use of 5-fluorouracil associated with oxaliplatin or CPT-11 have shown promising activity. The aim of the present study was to analyze the tolerability and activity of chemotherapy with 5-fluorouracil plus oxaliplatin or CPT-11 in elderly patients with advanced colorectal cancer. METHODS: Patients aged 70 years or older with advanced colorectal cancer were treated with 5-fluorouracil (400 mg/m2 in bolus and 600 mg/m2 in a 22-hr continuous infusion on days 1-2) plus folinic acid (100 mg/m2) associated to oxaliplatin (85 mg/m2 on day 1, FOLFOX regimen) or CPT-11 (180 mg/m2 on day 1, FOLFIRI regimen), every 14 days. RESULTS: Twenty-nine patients with a median age of 76 years (range, 70-82) were treated with FOLFOX or FOLFIRI as first-line chemotherapy for metastatic disease. We observed a partial response in 8/29 (27.6%), stable disease in 11/29 (37.9%) and progressive disease in 10/29 (34.5%). Median survival was 21 months; 1-year survival probability was 89.8%. Grade III leukopenia was observed in 2/29 (7%) patients and grade III diarrhea in 1/29 patients. No other grade III-IV toxicity was observed. CONCLUSIONS: FOLFOX and FOLFIRI appear to be active and well tolerated regimens for elderly patients with advanced colorectal cancer.