Elderly patients with hormone receptor-positive HER2-negative metastatic breast cancer treated with CDK4/6 inhibitors in a multicentre cohort.

INTRODUCTION: Cyclin-dependent kinases 4/6 inhibitors (CDK 4/6i) combined with endocrine therapy have become the gold standard in hormone receptor-positive (HR +) HER2-negative (HER2-) metastatic breast cancer (MBC). However, there is a significant lack of data regarding the efficacy and safety of these treatments in elderly patients. We present the results of a real-world data (RWD) cohort stratified by age at treatment initiation (≥ 70 years compared to patients < 70 years). METHODS: Clinico-pathological data of HR + HER2- MBC patients who were candidates for CDK4/6i therapy between January 2017 and December 2020 at the Institut Català d'Oncologia (Spain) were retrospectively collected. The primary goal was to assess Progression-Free Survival (PFS), Overall Survival (OS), and safety outcomes within this patient population. RESULTS: A total of 274 patients with MBC who received CDK4/6i treatment were included in the study. Among them, 84 patients (30.8%) were aged ≥ 70 years, with a mean age of 75, while 190 patients (69.2%) were under the age of 70, with a mean age of 55.7 years. The most frequently observed grade 3-4 toxicity was neutropenia, with similar rates in both the < 70 group (43.9%) and the ≥ 70 group (47.9%) (p = 0.728). The median Progression-Free Survival (mPFS) for the first-line CDK4/6i treatment was 22 months (95% CI, 15.4-39.8) in the < 70 group and 20.8 months (95% CI 11.2-NR) in the ≥ 70 group (p = 0.67). Similarly, the median PFS for the second-line CDK4/6i treatment was 10.4 months (95% CI, 7.4-15.1) and 7.1 months (95% CI 4.4-21.3) (p = 0.79), respectively. Median overall survival (mOS) was not reached either for the first- and second-line treatment. CONCLUSIONS: Our RWD suggests that elderly patients, when compared to those under 70, experience similar survival outcomes and exhibit comparable tolerance for CDK4/6i therapy.

Gal-1 Expression Analysis in the GLIOCAT Multicenter Study: Role as a Prognostic Factor and an Immune-Suppressive Biomarker.

Glioblastoma (GBM) is the most frequent primary malignant brain tumor and has a dismal prognosis. Unfortunately, despite the recent revolution of immune checkpoint inhibitors in many solid tumors, these have not shown a benefit in overall survival in GBM patients. Therefore, new potential treatment targets as well as diagnostic, prognostic, and/or predictive biomarkers are needed to improve outcomes in this population. The ß-galactoside binding protein Galectin-1 (Gal-1) is a protein with a wide range of pro-tumor functions such as proliferation, invasion, angiogenesis, and immune suppression. Here, we evaluated Gal-1 expression by immunohistochemistry in a homogenously treated cohort of GBM (the GLIOCAT project) and correlated its expression with clinical and molecular data. We observed that Gal-1 is a negative prognostic factor in GBM. Interestingly, we observed higher levels of Gal-1 expression in the mesenchymal/classical subtypes compared to the less aggressive proneural subtype. We also observed a Gal-1 expression correlation with immune suppressive signatures of CD4 T-cells and macrophages, as well as with several GBM established biomarkers, including SHC1, PD-L1, PAX2, MEOX2, YKL-40, TCIRG1, YWHAG, OLIG2, SOX2, Ki-67, and SOX11. Moreover, Gal-1 levels were significantly lower in grade 4 IDH-1 mutant astrocytomas, which have a better prognosis. Our results confirm the role of Gal-1 as a prognostic factor and also suggest its value as an immune-suppressive biomarker in GBM.

In silico validation of RNA-Seq results can identify gene fusions with oncogenic potential in glioblastoma.

RNA-Sequencing (RNA-Seq) can identify gene fusions in tumors, but not all these fusions have functional consequences. Using multiple data bases, we have performed an in silico analysis of fusions detected by RNA-Seq in tumor samples from 139 newly diagnosed glioblastoma patients to identify in-frame fusions with predictable oncogenic potential. Among 61 samples with fusions, there were 103 different fusions, involving 167 different genes, including 20 known oncogenes or tumor suppressor genes (TSGs), 16 associated with cancer but not oncogenes or TSGs, and 32 not associated with cancer but previously shown to be involved in fusions in gliomas. After selecting in-frame fusions able to produce a protein product and running Oncofuse, we identified 30 fusions with predictable oncogenic potential and classified them into four non-overlapping categories: six previously described in cancer; six involving an oncogene or TSG; four predicted by Oncofuse to have oncogenic potential; and 14 other in-frame fusions. Only 24 patients harbored one or more of these 30 fusions, and only two fusions were present in more than one patient: FGFR3::TACC3 and EGFR::SEPTIN14. This in silico study provides a good starting point for the identification of gene fusions with functional consequences in the pathogenesis or treatment of glioblastoma.

RNA sequencing and Immunohistochemistry Reveal ZFN7 as a Stronger Marker of Survival than Molecular Subtypes in G-CIMP-negative Glioblastoma.

PURPOSE: Glioblastoma is the most aggressive brain tumor in adults and has few therapeutic options. The study of molecular subtype classifications may lead to improved prognostic classification and identification of new therapeutic targets. The Cancer Genome Atlas (TCGA) subtype classification has mainly been applied in U.S. clinical trials, while the intrinsic glioma subtype (IGS) has mainly been applied in European trials. EXPERIMENTAL DESIGN: From paraffin-embedded tumor samples of 432 patients with uniformly treated, newly diagnosed glioblastoma, we built tissue microarrays for IHC analysis and applied RNA sequencing to the best samples to classify them according to TCGA and IGS subtypes. RESULTS: We obtained transcriptomic results from 124 patients. There was a lack of agreement among the three TCGA classificatory algorithms employed, which was not solely attributable to intratumoral heterogeneity. There was overlapping of TCGA mesenchymal subtype with IGS cluster 23 and of TCGA classical subtype with IGS cluster 18. Molecular subtypes were not associated with prognosis, but levels of expression of 13 novel genes were identified as independent prognostic markers in glioma-CpG island methylator phenotype-negative patients, independently of clinical factors and MGMT methylation. These findings were validated in at least one external database. Three of the 13 genes were selected for IHC validation. In particular, high ZNF7 RNA expression and low ZNF7 protein expression were strongly associated with longer survival, independently of molecular subtypes. CONCLUSIONS: TCGA and IGS molecular classifications of glioblastoma have no higher prognostic value than individual genes and should be refined before being applied to clinical trials.

A phase II randomized, multicenter, open-label trial of continuing adjuvant temozolomide beyond 6 cycles in patients with glioblastoma (GEINO 14-01).

BACKGROUND: Standard treatment for glioblastoma is radiation with concomitant and adjuvant temozolomide for 6 cycles, although the optimal number of cycles of adjuvant temozolomide has long been a subject of debate. We performed a phase II randomized trial investigating whether extending adjuvant temozolomide for more than 6 cycles improved outcome. METHODS: Glioblastoma patients treated at 20 Spanish hospitals who had not progressed after 6 cycles of adjuvant temozolomide were centrally randomized to stop (control arm) or continue (experimental arm) temozolomide up to a total of 12 cycles at the same doses they were receiving in cycle 6. Patients were stratified by MGMT methylation and measurable disease. The primary endpoint was differences in 6-month progression-free survival (PFS). Secondary endpoints were PFS, overall survival (OS), and safety (Clinicaltrials.gov NCT02209948). RESULTS: From August 2014 to November 2018, 166 patients were screened, 7 of whom were ineligible. Seventy-nine patients were included in the stop arm and 80 in the experimental arm. All patients were included in the analyses of outcomes and of safety. There were no differences in 6-month PFS (control 55.7%; experimental 61.3%), PFS, or OS between arms. MGMT methylation and absence of measurable disease were independent factors of better outcome. Patients in the experimental arm had more lymphopenia (P < 0.001), thrombocytopenia (P < 0.001), and nausea and vomiting (P = 0.001). CONCLUSIONS: Continuing temozolomide after 6 adjuvant cycles is associated with greater toxicity but confers no additional benefit in 6-month PFS. KEY POINTS: 1. Extending adjuvant temozolomide to 12 cycles did not improve 6-month PFS.2. Extending adjuvant temozolomide did not improve PFS or OS in any patient subset.3. Extending adjuvant temozolomide was linked to increased toxicities.

Phase III evaluating the addition of fulvestrant (F) to anastrozole (A) as adjuvant therapy in postmenopausal women with hormone receptor-positive HER2-negative (HR+/HER2-) early breast cancer (EBC): results from the GEICAM/2006-10 study.

PURPOSE: GEICAM/2006-10 compared anastrozole (A) versus fulvestrant plus anastrozole (A + F) to test the hypothesis of whether a complete oestrogen blockade is superior to aromatase inhibitors alone in breast cancer patients receiving hormone adjuvant therapy. METHODS: Multicenter, open label, phase III study. HR+/HER2- EBC postmenopausal patients were randomized 1:1 to adjuvant A (5 years [year]) or A + F (A plus F 250 mg/4 weeks for 3 year followed by 2 year of A). Stratification factors: prior chemotherapy (yes/no); number of positive lymph nodes (0/1-3/≥ 4); HR status (both positive/one positive) and site. PRIMARY OBJECTIVE: disease-free survival (DFS). Planned sample size: 2852 patients. RESULTS: The study has an early stop due to the financer decision with 870 patients (437 randomized to A and 433 to A + F). Patient characteristics were well balanced. After a median follow-up of 6.24y and 111 DFS events (62 in A and 49 in A + F) the Hazard Ratio for DFS (combination vs. anastrozole) was 0.84 (95% CI 0.58-1.22; p = 0.352). The proportion of patients disease-free in arms A and A + F at 5 year and 7 year were 90.8% versus 91% and 83.6% versus 86.7%, respectively. Most relevant G2-4 toxicities (≥ 5% in either arm) with A versus A + F were joint pain (14.7%; 13.7%), fatigue (2.5%; 7.2%), bone pain (3%; 6.5%), hot flushes (3.5%; 5%) and muscle pain (2.8%; 5.1%). CONCLUSIONS: The GEICAM/2006-10 study did not show a statistically significant increase in DFS by adding adjuvant F to A, though no firm conclusions can be drawn because of the limited sample size due to the early stop of the trial. ClinicalTrials.gov: NCT00543127.

Broad consensus on the optimal sequence for the systemic treatment of metastatic breast cancer: results from a survey of Spanish medical oncologists.

Objective: The aim of this survey conducted by 20 leading Spanish oncologists was to analyze the concurrence between Spanish clinical practice and the recently published definition of the optimal sequence for the systemic treatment of metastatic breast cancer (MBC) according to patient profiles. Methods: A self-administered questionnaire was developed, divided into five sections comprising 34 specific questions related to sequential treatments, plus three additional general questions. Respondents were asked to justify negative answers. Participants were recruited randomly by invitation out of a total of 619 oncologists. The questionnaire was sent and collected via e-mail between October 2015 and May 2016. A total of 191 completed questionnaires were received. Results: Overall, 70% of oncologists would keep the three patient profiles exactly as proposed (hormone receptor-positive and HER2-negative, HER2-positive, and triple negative breast cancer). Affirmative answers to questions regarding treatment sequences for these patient profiles (1-34) ranged from 77.8-99.5%, with an average of 90.9% of oncologists being in agreement with the recommended sequential treatments. The lowest degree of consensus was observed for endocrine treatments in pre-menopausal women and for chemotherapy options in hormone-resistant patients, whilst the highest degree of consensus was reached for targeted therapies in HER2-positive patients and for endocrine therapy in post-menopausal women. In their comments, participants revealed a number of economic constraints that prevented them from implementing some of the best treatment options. Conclusions: In conclusion, despite the complexity of MBC treatment, there is general agreement on the optimal treatment sequences.

Macrovascular Networks on Contrast-Enhanced Magnetic Resonance Imaging Improves Survival Prediction in Newly Diagnosed Glioblastoma.

A higher degree of angiogenesis is associated with shortened survival in glioblastoma. Feasible morphometric parameters for analyzing vascular networks in brain tumors in clinical practice are lacking. We investigated whether the macrovascular network classified by the number of vessel-like structures (nVS) visible on three-dimensional T1-weighted contrast⁻enhanced (3D-T1CE) magnetic resonance imaging (MRI) could improve survival prediction models for newly diagnosed glioblastoma based on clinical and other imaging features. Ninety-seven consecutive patients (62 men; mean age, 58 ± 15 years) with histologically proven glioblastoma underwent 1.5T-MRI, including anatomical, diffusion-weighted, dynamic susceptibility contrast perfusion, and 3D-T1CE sequences after 0.1 mmol/kg gadobutrol. We assessed nVS related to the tumor on 1-mm isovoxel 3D-T1CE images, and relative cerebral blood volume, relative cerebral flow volume (rCBF), delay mean time, and apparent diffusion coefficient in volumes of interest for contrast-enhancing lesion (CEL), non-CEL, and contralateral normal-appearing white matter. We also assessed Visually Accessible Rembrandt Images scoring system features. We used ROC curves to determine the cutoff for nVS and univariate and multivariate cox proportional hazards regression for overall survival. Prognostic factors were evaluated by Kaplan-Meier survival and ROC analyses. Lesions with nVS > 5 were classified as having highly developed macrovascular network; 58 (60.4%) tumors had highly developed macrovascular network. Patients with highly developed macrovascular network were older, had higher volumeCEL, increased rCBFCEL, and poor survival; nVS correlated negatively with survival (r = -0.286; p = 0.008). On multivariate analysis, standard treatment, age at diagnosis, and macrovascular network best predicted survival at 1 year (AUC 0.901, 83.3% sensitivity, 93.3% specificity, 96.2% PPV, 73.7% NPV). Contrast-enhanced MRI macrovascular network improves survival prediction in newly diagnosed glioblastoma.

Changes in metabolic risk, insulin resistance, leptin and adiponectin following a lifestyle intervention in overweight and obese breast cancer survivors.

Adiposity and physical activity are modifiable factors that could be important determinants of breast cancer (BC) prognosis through their effects on endogenous reproductive hormones, chronic inflammation and metabolic changes. Therefore, it is necessary to evaluate whether offering lifestyle interventions to BC survivors could affect the levels of certain biomarkers involved in these mechanisms. We designed a pre-post intervention study offering diet and exercise sessions over 12 weeks to 42 overweight/obese BC survivors. Before and after the intervention, we obtained dietary information, anthropometry and cardiorespiratory fitness (CRF) measurements and blood samples to measure metabolic risk, insulin resistance and adipokines biomarkers. Wilcoxon signed-rank tests and Spearman partial correlation coefficients were used to compare pre- and post-measurements and assess the correlations between changes in biomarkers and changes in anthropometry and CRF. Breast cancer survivors showed significant improvements in metabolic risk biomarkers and insulin resistance indicators along with a non-significant leptin decrease and a significant adiponectin decrease. The improvements in metabolic risk biomarkers, insulin resistance indicators and leptin were moderately correlated (0.32 ≤ |r| ≤ 0.55) with the decrease in body mass index and the increase in CRF. Diet and exercise interventions implemented in overweight/obese BC survivors may improve metabolic risk, insulin resistance and leptin biomarkers.

Pseudoprogression as an adverse event of glioblastoma therapy.

We explored predictive factors of pseudoprogression (PsP) and its impact on prognosis in a retrospective series of uniformly treated glioblastoma patients. Patients were classified as having PsP, early progression (eP) or neither (nP). We examined potential associations with clinical, molecular, and basal imaging characteristics and compared overall survival (OS), progression-free survival (PFS), post-progression survival (PPS) as well as the relationship between PFS and PPS in the three groups. Of the 256 patients studied, 56 (21.9%) were classified as PsP, 70 (27.3%) as eP, and 130 (50.8%) as nP. Only MGMT methylation status was associated to PsP. MGMT methylated patients had a 3.5-fold greater possibility of having PsP than eP (OR: 3.48; 95% CI: 1.606-7.564; P = 0.002). OS was longer for PsP than eP patients (18.9 vs. 12.3 months; P = 0.0001) but was similar for PsP and nP patients (P = 0.91). OS was shorter-though not significantly so-for PsP than nP patients (OS: 19.5 vs. 27.9 months; P = 0.63) in methylated patients. PPS was similar for patients having PsP, eP or nP (PPS: 7.2 vs. 5.4 vs. 6.7; P = 0.43). Neurological deterioration occurred in 64.3% of cases at the time they were classified as PsP and in 72.8% of cases of eP (P = 0.14). PsP confounds the evaluation of disease and does not confer a survival advantage in glioblastoma.

Descriptive epidemiology of primary malignant and non-malignant central nervous tumors in Spain: Results from the Girona Cancer Registry (1994-2013).

BACKGROUND: Systematic registration of non-malignant central nervous system (CNS) tumors is a rare practice among European cancer registries. Thus, the real burden of all CNS tumors across Europe is underestimated. The Girona Cancer Registry provides here the first data on CNS tumor incidence and survival trends in Spain for all histological types, including malignant and non-malignant tumors. METHODS: Data on all incident cases of primary CNS tumors notified to the Girona population-based cancer registry from 1994 to 2013 (n=2,131) were reviewed. Incidences rates (IRs) were standardized to the 2013 European population and annual percentage changes (EAPC) were estimated using a piecewise log linear model. 1- and 5-year observed (OS) and relative survival (RS) were also calculated. Results were expressed by sex, age-group, histological subtype and behavior. RESULTS: The overall IR was 16.85 and increased across the period of study (EAPC=+2.2%). The proportion and IRs of malignant (50.2%; IR=9.35) and non-malignant cases (49.8%; IR=9.14) were similar; however, non-malignant tumors were more frequent in women (sex ratio=0.63). The most frequently reported histologies were meningioma (27.6%; IR=5.11) and glioblastoma (22.2%; IR=4.15), which also accounted for the highest and lowest 5-year RS (80.2%; 3.7%, respectively). Globally, 5-year RS was lower in men (42.6% vs. 58.3%, respectively) and in the elderly (64.9% for 0-14years vs. 23.0% for >74years). CONCLUSION: This study presents a comprehensive overview of the epidemiology of malignant and non-malignant CNS primary tumors from the well-established region-wide Girona Cancer Registry (1994-2013). Incidence rates were recovered for all histologies. Survival is still dramatically associated to both age and histological subtype.

A Comparison of RNA-Seq Results from Paired Formalin-Fixed Paraffin-Embedded and Fresh-Frozen Glioblastoma Tissue Samples.

The molecular classification of glioblastoma (GBM) based on gene expression might better explain outcome and response to treatment than clinical factors. Whole transcriptome sequencing using next-generation sequencing platforms is rapidly becoming accepted as a tool for measuring gene expression for both research and clinical use. Fresh frozen (FF) tissue specimens of GBM are difficult to obtain since tumor tissue obtained at surgery is often scarce and necrotic and diagnosis is prioritized over freezing. After diagnosis, leftover tissue is usually stored as formalin-fixed paraffin-embedded (FFPE) tissue. However, RNA from FFPE tissues is usually degraded, which could hamper gene expression analysis. We compared RNA-Seq data obtained from matched pairs of FF and FFPE GBM specimens. Only three FFPE out of eleven FFPE-FF matched samples yielded informative results. Several quality-control measurements showed that RNA from FFPE samples was highly degraded but maintained transcriptomic similarities to RNA from FF samples. Certain issues regarding mutation analysis and subtype prediction were detected. Nevertheless, our results suggest that RNA-Seq of FFPE GBM specimens provides reliable gene expression data that can be used in molecular studies of GBM if the RNA is sufficiently preserved.

Prolonged survival after bevacizumab rechallenge in glioblastoma patients with previous response to bevacizumab†.

BACKGROUND: The use of bevacizumab for recurrent glioblastoma is controversial. Here we show data on patients who responded to bevacizumab, then stopped bevacizumab for any reason other than progression and were rechallenged with bevacizumab at the time of subsequent progression. METHODS: This retrospective study included 28 patients, classified in 2 cohorts: those for whom the first exposure to bevacizumab (BEV-1) was first-line treatment for newly diagnosed glioblastoma (Bev-F; N = 12) and those for whom BEV-1 was second- or third-line treatment for recurrent disease after standard treatment (Bev-S; N = 16). RESULTS: All patients received standard radiotherapy plus temozolomide. Bev-F patients also received concomitant bevacizumab. All 28 patients received a total of 57 treatment lines with bevacizumab (12 first-line and 45 second- or further-line). Twenty-nine lines were rechallenges (BEV-2 [N = 26] or BEV-3 [N = 3]). Objective response to rechallenge was 58.6% and clinical benefit was 89.6%. Overall survival (OS) was 55 months for RPA class IV and 26.7 months for RPA class V patients (P = .01). OS was 26.7 months for Bev-F patients and 52.1 months for Bev-S patients (P = .004). Post-progression survival was 20 months for Bev-F patients and 39.6 months for Bev-S patients (HR = 0.26; P = .007). CONCLUSION: This is the largest study to examine the impact of a bevacizumab rechallenge in glioblastoma patients who had responded to previous bevacizumab treatment but who stopped before progression. Our findings indicate that these patients can attain a second response or clinical benefit from re-introduction of bevacizumab. The potential benefit from intermittent versus continuous treatment warrants comparison in clinical trials.

Anti-HER2 Therapy Beyond Second-Line for HER2-Positive Metastatic Breast Cancer: A Short Review and Recommendations for Several Clinical Scenarios from a Spanish Expert Panel.

BACKGROUND: The aim of this project was to provide an expert opinion regarding anti-human epidermal growth factor receptor 2 (HER2) therapy beyond second-line treatment of metastatic breast cancer (mBC). METHODS: A group of experts discussed specific issues concerning anti-HER2 therapy in late-line settings in mBC. RESULTS: Trastuzumab emtansine (T-DM1) or dual HER2 blockade appeared to be good options for HER2-positive mBC after ≥ 2 HER2-targeted therapies. Once an objective response has been achieved with anti-HER2-containing therapy, the anti-HER2 agent can be continued until progression of the disease, unacceptable toxicity or patient decision. mBC treated with ≥ 3 consecutive lines of anti-HER therapy, ≥ 1 being a dual HER2 blockade and with early progression of disease during a fourth or later-line treatment, are clinically resistant to anti-HER therapy. For progression of metastasis in the brain after anti-HER2 therapy, lapatinib and chemotherapy appear to be a good alternative after best local treatment. CONCLUSIONS: Further clinical trials are needed to provide valuable knowledge about the best treatment options in the later settings of mBC.

Comparison of alternating pressure mattresses and overlays for prevention of pressure ulcers in ventilated intensive care patients: a quasi-experimental study.

AIM: To compare the effectiveness of alternating pressure air mattresses vs. overlays to prevent pressure ulcers in mechanically ventilated patients in intensive care units. BACKGROUND: Pressure ulcers prevention is an important issue in the nursing of critically ill patients. It is not clear whether alternating pressure air mattresses are more effective than overlays to prevent pressure ulcers. DESIGN: Prospective quasi-experimental study. METHODS: A prospective quasi-experimental study was conducted among patients in the medical-surgery intensive care unit of a university hospital on mechanical ventilation ≥24 hours during two time periods (2001 and 2006). Overlays were used in 2001 and mattresses in 2006. Primary outcome was the incidence of pressure ulcers grade ≥II (according to the European Pressure Ulcer Advisory Panel) during intensive care unit stay. RESULTS: The study included 221 patients (116 in 2001 and 105 in 2006). Baseline characteristics were similar between groups except for a higher Acute Physiology and Chronic Health Evaluation III score, total and first-day respiratory Sequential Organ Failure Assessment Score on day 1 in overlay group. There was significantly lower incidence density in the mattress vs. overlay group (12·41 cases/1000 days vs. 18·67 cases/1000 days of stay). The multivariate analyses showed the use of the mattress to be a protective factor against pressure ulcer onset. CONCLUSION: This quasi-experiment study that alternative pressure air mattresses were more effective than alternating pressure air overlays in preventing pressure ulcers in mechanically ventilated critical care patients.

Metformin lowers the threshold for stress-induced senescence: a role for the microRNA-200 family and miR-205.

We have tested the hypothesis that the antidiabetic biguanide metformin can be used to manipulate the threshold for stress-induced senescence (SIS), thus accelerating the onset of cancer-protective cellular senescence in response to oncogenic stimuli. Using senescence-prone murine embryonic fibroblasts (MEFs), we assessed whether metformin treatment modified the senescence phenotype that is activated in response to DNA damaging inducers. Metformin significantly enhanced the number of MEFs entering a senescent stage in response to doxorubicin, an anthracycline that induces cell senescence by activating DNA damage signaling pathways (e.g., ATM/ATR) in a reactive oxygen species (ROS)-dependent manner. Using WI-38 and BJ-1 human diploid fibroblasts (HDFs), we explored whether metformin supplementation throughout their entire replicative lifespan may promote the early appearance of the biomarkers of replicative senescence. Chronic metformin significantly reduced HDFs' lifespan by accelerating both the loss of replicative potential and the acquisition of replicative senescence-related biomarkers (e.g., enlarged and flattened cell shapes, loss of arrayed arrangement, accumulation of intracellular and extracellular debris and SA-ß-gal-positive staining). Metformin functioned as a bona fide stressful agent, inducing monotonic, dose-dependent, SIS-like responses in BJ-1 HDFs, which are highly resistant to ROS-induced premature senescence. Metformin-induced SIS in BJ-1 fibroblasts was accompanied by the striking activation of several microRNAs belonging to the miR-200s family (miR-200a, miR-141 and miR429) and miR-205, thus mimicking a recently described ability of ROS to chemosensitize cancer cells by specifically upregulating anti-EMT (epithelial-to-mesenchymal transition) miR-200s. Because the unlimited proliferative potential of stem cells results from their metabolic refractoriness to SIS, we finally tested if metformin treatment could circumvent the stress (e.g., ROS)-resistant phenotype of induced pluripotent stem cells (iPSCs). Metformin treatment drastically reduced both the number and the size of iPSC colonies and notably diminished the staining of the pluripotency marker alkaline phosphatase. Our current findings, altogether, reveal for the first time that metformin can efficiently lower the threshold for SIS to generate an "stressed" cell phenotype that becomes pre-sensitized to oncogenic-like stimuli, including DNA damaging, proliferative and/or stemness inducers.

Metformin: multi-faceted protection against cancer.

The biguanide metformin, a widely used drug for the treatment of type 2 diabetes, may exert cancer chemopreventive effects by suppressing the transformative and hyperproliferative processes that initiate carcinogenesis. Metformin's molecular targets in cancer cells (e.g., mTOR, HER2) are similar to those currently being used for directed cancer therapy. However, metformin is nontoxic and might be extremely useful for enhancing treatment efficacy of mechanism-based and biologically targeted drugs. Here, we first revisit the epidemiological, preclinical, and clinical evidence from the last 5 years showing that metformin is a promising candidate for oncology therapeutics. Second, the anticancer effects of metformin by both direct (insulin-independent) and indirect (insulin-dependent) mechanisms are discussed in terms of metformin-targeted processes and the ontogenesis of cancer stem cells (CSC), including Epithelial-to-Mesenchymal Transition (EMT) and microRNAs-regulated dedifferentiation of CSCs. Finally, we present preliminary evidence that metformin may regulate cellular senescence, an innate safeguard against cellular immortalization. There are two main lines of evidence that suggest that metformin's primary target is the immortalizing step during tumorigenesis. First, metformin activates intracellular DNA damage response checkpoints. Second, metformin attenuates the anti-senescence effects of the ATP-generating glycolytic metabotype-the Warburg effect-, which is required for self-renewal and proliferation of CSCs. If metformin therapy presents an intrinsic barrier against tumorigenesis by lowering the threshold for stress-induced senescence, metformin therapeutic strategies may be pivotal for therapeutic intervention for cancer. Current and future clinical trials will elucidate whether metformin has the potential to be used in preventive and treatment settings as an adjuvant to current cancer therapeutics.

Repositioning chloroquine and metformin to eliminate cancer stem cell traits in pre-malignant lesions.

Ideal oncology drugs would be curative after a short treatment course if they could eliminate epithelium-originated carcinomas at their non-invasive, pre-malignant stages. Such ideal molecules, which are expected to molecularly abrogate all the instrumental mechanisms acquired by migrating cancer stem cells (CSCs) to by-pass tumour suppressor barriers, might already exist. We here illustrate how system biology strategies for repositioning existing FDA-approved drugs may accelerate our therapeutic capacity to eliminate CSC traits in pre-invasive intraepithelial neoplasias. First, we describe a signalling network signature that overrides bioenergetics stress- and oncogene-induced senescence (OIS) phenomena in CSCs residing at pre-invasive lesions. Second, we functionally map the anti-malarial chloroquine and the anti-diabetic metformin ("old drugs") to their recently recognized CSC targets ("new uses") within the network. By discussing the preclinical efficacy of chloroquine and metformin to inhibiting the genesis and self-renewal of CSCs we finally underscore the expected translational impact of the "old drugs-new uses" repurposing strategy to open a new CSC-targeted chemoprevention era.

Micro(mi)RNA expression profile of breast cancer epithelial cells treated with the anti-diabetic drug metformin: induction of the tumor suppressor miRNA let-7a and suppression of the TGFß-induced oncomiR miRNA-181a.

An unexplored molecular scenario that might explain the inhibitory impact of the anti-diabetic drug metformin on the genesis of breast cancer relates to metformin's ability to modulate the expression status of micro (mi)RNAs. We here report the first miRNA expression profiling of human epithelial breast cancer cells cultured in the presence of metformin. We conducted real-time transcription polymerase chain reaction (qRT-PCR) Arrays to quantitatively compare the expression profile of 88 cancer-related miRNA sequences before and after treatment of MCF-7 cells, which were used as well-differentiated, epithelioid cell controls, with graded concentrations of metformin. Metformin-treated MCF-7 cells notably exhibited up to 18-fold increases in miRNA lethal-7a (let-7a) expression compared with untreated control cells. We confirmed that MCF-7 cells undergoing epithelial-to-mesenchymal (EMT) transition in response to the cytokine TGFß notably up-regulated (~5-fold) miRNA-181a expression and exhibited better mammosphere-forming capabilities. We then explored the ability of metformin to impede TGFß-enhanced propensity of breast cancer stem cells to form mammospheres in a miRNA-181a-related manner. Remarkably, TGFß treatment failed to up-regulate miRNA-181a expression in the presence of metformin, which was able to fully abrogate TGFß-enhanced mammosphere-forming ability. In addition, metformin co-treatment fully prevented TGFß-induced down-regulation of the tumor suppressor miRNA-96 (~10-fold). Metformin's molecular functioning to prevent invasive breast cancer can be explained in terms of its previously unrecognized ability to efficiently up-regulate the tumor-suppressive miRNAs let-7a & miRNA-96 and inhibit the oncogenic miRNA-181a, thus epigenetically preserving the differentiated phenotype of mammary epithelium while preventing EMT-related cancer-initiating cell self-renewal.