Identification of a novel RNA aptamer that selectively targets breast cancer exosomes.

Breast cancer is a leading cause of cancer mortality in women. Despite advances in its management, the identification of new options for early-stage diagnosis and therapy of this tumor still represents a crucial challenge. Increasing evidence indicates that extracellular vesicles called exosomes may have great potential as early diagnostic biomarkers and regulators of many cancers, including breast cancer. Therefore, exploiting molecules able to selectively recognize them is of great interest. Here, we developed a novel differential SELEX strategy, called Exo-SELEX, to isolate nucleic acid aptamers against intact exosomes derived from primary breast cancer cells. Among the obtained sequences, we optimized a high-affinity aptamer (ex-50.T) able to specifically recognize exosomes from breast cancer cells or patient serum samples. Furthermore, we demonstrated that the ex.50.T is a functional inhibitor of exosome cellular uptake and antagonizes cancer exosome-induced cell migration in vitro. This molecule provides an innovative tool for the specific exosome detection and the development of new therapeutic approaches for breast cancer.

miR-216a Acts as a Negative Regulator of Breast Cancer by Modulating Stemness Properties and Tumor Microenvironment.

Breast cancer is the most frequent malignancy in females in terms of both incidence and mortality. Underlying the high mortality rate is the presence of cancer stem cells, which divide indefinitely and are resistant to conventional chemotherapies, so causing tumor relapse. In the present study, we identify miR-216a-5p as a downregulated microRNA in breast cancer stem cells vs. the differentiated counterpart. We demonstrate that overexpression of miR-216a-5p impairs stemness markers, mammosphere formation, ALDH activity, and the level of Toll-like receptor 4 (TLR4), which plays a significant role in breast cancer progression and metastasis by leading to the release of pro-inflammatory molecules, such as interleukin 6 (IL-6). Indeed, miR-216a regulates the crosstalk between cancer cells and the cells of the microenvironment, in particular cancer-associated fibroblasts (CAFs), through regulation of the TLR4/IL6 pathway. Thus, miR-216a has an important role in the regulation of stem phenotype, decreasing stem-like properties and affecting the cross-talk between cancer cells and the tumor microenvironment.

Cancer-associated fibroblasts release exosomal microRNAs that dictate an aggressive phenotype in breast cancer.

Cancer-associated fibroblasts (CAFs) are the major components of the tumor microenvironment. They may drive tumor progression, although the mechanisms involved are still poorly understood. Exosomes have emerged as important mediators of intercellular communication in cancer. They mediate horizontal transfer of microRNAs (miRs), mRNAs and proteins, thus affecting breast cancer progression. Differential expression profile analysis identified three miRs (miRs -21, -378e, and -143) increased in exosomes from CAFs as compared from normal fibroblasts. Immunofluorescence indicated that exosomes may be transferred from CAFs to breast cancer cells, releasing their cargo miRs. Breast cancer cells (BT549, MDA-MB-231, and T47D lines) exposed to CAF exosomes or transfected with those miRs exhibited a significant increased capacity to form mammospheres, increased stem cell and epithelial-mesenchymal transition (EMT) markers, and anchorage-independent cell growth. These effects were reverted by transfection with anti-miRs. Similarly to CAF exosomes, normal fibroblast exosomes transfected with miRs -21, -378e, and -143 promoted the stemness and EMT phenotype of breast cancer cells. Thus, we provided evidence for the first time of the role of CAF exosomes and their miRs in the induction of the stemness and EMT phenotype in different breast cancer cell lines. Indeed, CAFs strongly promote the development of an aggressive breast cancer cell phenotype.

MiR-221 promotes stemness of breast cancer cells by targeting DNMT3b.

Cancer stem cells (CSCs) are a small part of the heterogeneous tumor cell population possessing self-renewal and multilineage differentiation potential as well as a great ability to sustain tumorigenesis. The molecular pathways underlying CSC phenotype are not yet well characterized. MicroRNAs (miRs) are small noncoding RNAs that play a powerful role in biological processes. Early studies have linked miRs to the control of self-renewal and differentiation in normal and cancer stem cells. We aimed to study the functional role of miRs in human breast cancer stem cells (BCSCs), also named mammospheres. We found that miR-221 was upregulated in BCSCs compared to their differentiated counterpart. Similarly, mammospheres from T47D cells had an increased level of miR-221 compared to differentiated cells. Transfection of miR-221 in T47D cells increased the number of mammospheres and the expression of stem cell markers. Among miR-221's targets, we identified DNMT3b. Furthermore, in BCSCs we found that DNMT3b repressed the expression of various stemness genes, such as Nanog and Oct 3/4, acting on the methylation of their promoters, partially reverting the effect of miR-221 on stemness. We hypothesize that miR-221 contributes to breast cancer tumorigenicity by regulating stemness, at least in part through the control of DNMT3b expression.

Effects on quality of life of weekly docetaxel-based chemotherapy in patients with locally advanced or metastatic breast cancer: results of a single-centre randomized phase 3 trial.

BACKGROUND: To evaluate whether weekly schedules of docetaxel-based chemotherapy were superior to 3-weekly ones in terms of quality of life in locally advanced or metastatic breast cancer. METHODS: Patients with locally advanced or metastatic breast cancer, aged ≤ 70 years, performance status 0-2, chemotherapy-naive for metastatic disease, were eligible. They were randomized to weekly or 3-weekly combination of docetaxel and epirubicin, if they were not treated with adjuvant anthracyclines, or docetaxel and capecitabine, if treated with adjuvant anthracyclines. Primary end-point was global quality of life change at 6-weeks, measured by EORTC QLQ-C30. With two-sided alpha 0.05 and 80% power for 35% effect size, 130 patients per arm were needed. RESULTS: From February 2004 to March 2008, 139 patients were randomized, 70 to weekly and 69 to 3-weekly arm; 129 and 89 patients filled baseline and 6-week questionnaires, respectively. Global quality of life was better in the 3-weekly arm (p = 0.03); patients treated with weekly schedules presented a significantly worsening in role functioning and financial scores (p = 0.02 and p < 0.001). Neutropenia and stomatitis were worse in the 3-weekly arm, where two toxic deaths were observed. Overall response rate was 39.1% and 33.3% in 3-weekly and weekly arms; hazard ratio of progression was 1.29 (95% CI: 0.84-1.97) and hazard ratio of death was 1.38 (95% CI: 0.82-2.30) in the weekly arm. CONCLUSIONS: In this trial, the weekly schedules of docetaxel-based chemotherapy appear to be inferior to the 3-weekly one in terms of quality of life in patients with locally advanced or metastatic breast cancer. TRIAL REGISTRATION: ClinicalTrials.gov NCT00540800.

Weekly docetaxel versus CMF as adjuvant chemotherapy for elderly breast cancer patients: safety data from the multicentre phase 3 randomised ELDA trial.

Within an ongoing multicentre phase 3 randomised trial (ELDA, cancertrials.gov ID: NCT00331097), early breast cancer patients, 65-79 years old, with average to high risk of recurrence, are randomly assigned to receive CMF (cyclophosphamide 600 mg/m2, methotrexate 40 mg/m2, fluorouracil 600 mg/m2, days 1-8) or docetaxel (35 mg/m2 days 1-8-15), every 4 weeks. Here we report an unplanned safety analysis prompted by an amendment introducing creatinine clearance as a tool to adjust methotrexate dose. Before such change, 101 patients with a median age of 70 were randomly assigned CMF (53 patients) or docetaxel (48 patients). At least one grades 3-4 toxic event of any type was reported in 40 (75.5%) and 19 (39.6%) patients with CMF and docetaxel, respectively (p=0.0002). Grades 3-4 hematological events were observed in 37 (69.8%) vs. 4 (8.3%) cases (p<0.0001) and grades 3-4 non-hematological toxicity in 12 (22.6%) vs. 15 (31.2%) patients (p=0.11), with CMF and docetaxel, respectively. A higher incidence of anemia, neutropenia, thrombocytopenia and febrile neutropenia was reported with CMF. Constipation, mucositis, nausea and vomiting were more common with CMF; diarrhoea, abdominal pain, dysgeusia, neuropathy and liver toxicity were more frequent with docetaxel. No significant interaction was found between the occurrence of severe toxicity and baseline variables, including creatinine clearance and geriatric activity scales. In conclusion, weekly docetaxel appears to be less toxic than CMF in terms of hematological toxicity.

Vinorelbine plus 3-weekly trastuzumab in metastatic breast cancer: a single-centre phase 2 trial.

BACKGROUND: After two studies reporting response rates higher than 70% in HER2-positive metastatic breast cancer with weekly trastuzumab and vinorelbine, we planned a phase 2 study to test activity of the same combination, with trastuzumab given every 3 weeks. METHODS: Patients with HER2-positive metastatic breast cancer (3+ at immunohistochemistry or positive at fluorescence in situ hybridization), PS < or =2, normal left-ventricular ejection fraction (LVEF) and no more than one chemotherapy line for metastatic disease were eligible. Vinorelbine (30 mg/m2) was given on days 1 & 8 every 21 and trastuzumab (8 mg/kg day 1, then 6 mg/kg) every 21 days). A single-stage phase 2 design, with p0 = 0.45, p1 = 0.65, type I and II error = 0.10, was applied; 22 objective responses were required in 39 patients. RESULTS: From Nov 2002 to May 2005, 50 patients were enrolled, with a median age of 54 years (range 31-81). Among 40 patients eligible for response assessment, there were 7 complete and 13 partial responses (overall response rate 50%; 95% exact CI 33.8-66.2); 11 patients had disease stabilization, lasting more than 6 months in 10 cases. Response rate did not vary according to patients and tumor characteristics, type and amount of previous chemotherapy. Within the whole series, median progression-free survival was 9.6 months (95% CI 7.3-12.3), median overall survival 22.7 months (95% CI 19.5-NA). Fifteen patients (30%) developed brain metastases at a median time of 12 months (range 1-25). There was one toxic death due to renal failure in a patient receiving concomitant pamidronate. Twenty-three patients (46%) had grade 3-4 neutropenia, 2 (4%) grade 3 anemia, 4 (8%) febrile neutropenia. Two patients stopped treatment because of grade 2 decline of LVEF and one patient because of grade 2 liver toxicity concomitant with a grade 1 decline of LVEF. One patient stopped trastuzumab after 50 cycles because of grade 1 decline of LVEF. CONCLUSION: Although lower than in initial studies, activity of 3-weekly trastuzumab plus vinorelbine fell within the range of results reported with weekly schedules. Toxicity was prevalently manageable. This combination is safe and active for metastatic breast cancer patients who received adjuvant taxanes with anthracyclines.

Biweekly docetaxel-irinotecan treatment with filgrastim support is highly active in antracycline-Paclitaxel-refractory breast cancer patients.

PURPOSE: To evaluate the feasibility and activity of combination treatment with docetaxel (DTX) and irinotecan (CPT-11), given together every other week, combined with filgrastim support, in anthracycline- and paclitaxel-pretreated breast cancer (BC) patients. PATIENTS AND METHODS: Advanced BC patients pretreated with anthracycline- and paclitaxel-based chemotherapy were eligible. DTX (80 mg/m2) and CPT-11 (100 mg/m2) were given biweekly with filgrastim support (300 microg/day on days 4-7). RESULTS: Fifty patients (48 with metastatic and 2 with locally advanced cancer) were enrolled, with a total of 318 cycles being delivered. Thirty-one patients had visceral localizations. All patients had received epirubicin plus paclitaxel, with or without cisplatin, as front-line treatment for advanced disease. Overall, fatigue and diarrhea were the main chemotherapy-related toxicities in this study, being severe in 10 (20%) and 4 (8%) patients. Grade 3 or 4 neutropenia and thrombocytopenia occurred in 18 (36%) and 6 (12%) patients, respectively. Red blood cell transfusions were required in 4 patients. A total of 32 objective responses were registered (overall response rate, ORR = 64%, 95% confidence interval = 49-77%), including 8 complete responses (16%). An additional 8 patients showed stable disease. After a median follow-up of 18 (range 4-29) months, 30 patients were still alive, and 19 were progression free; median progression-free and overall survivals were 10 and 23 months, respectively. CONCLUSIONS: Biweekly DTX/CPT-11 with G-CSF support is a well-tolerated and highly effective approach in anthracycline-/paclitaxel-pretreated patients. The very promising ORR and survival outcome observed in this subset of patients with a poor prognosis suggest that this regimen might play a major role in the management of this disease.

Biweekly docetaxel-irinotecan with filgrastim support in pretreated breast and non-small-cell lung cancer patients. A phase I study.

BACKGROUND: Docetaxel (DTX) has been shown to be a very active drug in both breast cancer (BC) and non-small-cell lung cancer (NSCLC). Irinotecan (CPT-11) is also active in NSCLC, and has shown promising antitumor activity in pretreated BC. PURPOSE. To define the MTDs of these two drugs given together every other week with the use of filgrastim support in pretreated BC and NSCLC patients. PATIENTS AND METHODS: Patients (aged 18-70 years, performance status < or =2) with advanced NSCLC or BC who had received at least one prior chemotherapy regimen were candidates for this phase I study. The starting DTX and CPT-11 doses were 60 mg/m(2) and 80 mg/m(2). Doses were alternately escalated at each step by 10 mg/m(2) for both drugs. Filgrastim 300 microg/day was given subcutaneously from days 4 through 7 of each cycle. RESULTS: From April 2000, 41 patients were included in the trial (27 BC, 14 NSCLC). All BC patients had received epirubicin plus paclitaxel (with or without cisplatin) as first-line treatment. Of the 14 NSCLC patients, 12 had received cisplatin-based first-line therapy, and 8 patients had been pretreated with paclitaxel. The dose escalation proceeded through five dose levels up to DTX and CPT-11 doses of 80 mg/m(2) and 100 mg/m(2), respectively. Overall, ten patients showed dose-limiting toxicity during the first cycle, diarrhea in seven and neutropenia in the remaining three. Considering all 218 cycles delivered, grade 3 or 4 neutropenia occurred in 14 patients (34%), with only one episode of neutropenic fever, while severe diarrhea was observed in 9 patients (23%). A total of 21 objective responses were registered (four complete) for an overall response rate of 51% [95% CI 35-67]. A major response was seen in 16 of the 27 BC patients (59%) and in 5 of the 14 NSCLC patients (36%). CONCLUSIONS: DTX and CPT-11 can be safely given together biweekly at adequate doses, with filgrastim support. In view of the promising activity data in both groups, phase II studies testing this combination in pretreated BC and NSCLC patients are ongoing.

A phase I-II study on a gemcitabine-cyclophosphamide-fluorouracil/folinic acid triplet combination in anthracycline- and taxane-refractory breast cancer patients.

PURPOSE: To define the cyclophosphamide (CTX) maximal tolerated dose when combined with fixed doses of gemcitabine, fluorouracil (5-FU) and folinic acid (leucovorin, LFA) in metastatic breast cancer patients pretreated with anthracyclines and taxanes. METHODS: Metastatic breast cancer patients aged < or = 75 years, with ECOG performance status 0-2, were eligible, provided that they had received previous anthracycline- and taxane-based chemotherapy for the advanced disease. Chemotherapy consisted of gemcitabine 1,000 mg/m(2), 5-FU 425 mg/m(2), LFA 100 mg/m(2) and escalating doses of CTX, starting from 500 mg/m(2), on days 1 and 8 every 3 weeks. The dose escalation was stopped if dose-limiting toxicity (DLT) occurred in > 33% of patients of a given cohort. After the definition of DLT, a further escalation with the addition of granulocyte colony-stimulating factor (G-CSF; on days 3-5 and 10-12) was planned. RESULTS: Since March 1999, 69 patients have entered this trial through seven different cohorts. The dose escalation was stopped at the CTX dose of 600 mg/m(2) since 3/6 patients showed DLT. A further dose escalation was attempted in the presence of G-CSF support. A CTX dose of 800 mg/m(2) proved to be safe and was chosen for the phase II. A total of 33 patients were treated at this dose level. The treatment was fairly well tolerated, grade 3-4 neutropenia and thrombocytopenia occurring in 38 and 16% of patients, respectively. No cases of sepsis or bleeding were registered. Four patients required a packed red blood cell transfusion. Severe nonhematologic toxicity was also uncommon, occurring in 10 patients. Three complete and 24 partial responses were recorded for an overall response rate of 38% (95% CI = 26-50). Two complete and 12 partial responses were recorded in the 33 patients treated in the phase II for an overall response rate (ORR) of 42% (95% CI = 25-61). CONCLUSIONS: The gemcitabine-CTX-5-FU/LFA combination is a well-tolerated treatment for poor-prognosis breast cancer patients with previous exposure to anthracyclines and taxanes. With the addition of G-CSF, a cumulative CTX dose of 1,600 mg/m(2) can be safely delivered every 3 weeks. The evidence of an ORR approaching 40% is very promising and justifies further evaluations in this subset of patients.