Analysis of molecular mechanisms and anti-tumoral effects of zoledronic acid in breast cancer cells

Background: Zoledronic acid (ZOL) is the most potent nitrogen-containing bisphosphonate (N-BPs) that strongly binds to bone mineral and acts as a powerful inhibitor of bone resorption, already clinically available for the treatment of patients with osteolytic metastases. Recent data also suggest that ZOL, used in breast cancer, may provide more than just supportive care modifying the course of the disease, though the possible molecular mechanism of action is still unclear. Aims: Since breast cancer is one of the primary tumors with high propensity to metastasize to the bone, we investigated, for the first time, differential gene expression profile on MCF-7 breast cancer cells treated with low doses of ZOL (10μM). Materials and Methods: Microarrays analysis was used to identify, describe and summarize evidences regarding the molecular basis of actions of ZOL and of their possible direct anti-tumor effects. We validated gene expression results of specific transcripts involved on major cellular process by Real Time and Western Blot analysis and we observed inhibition of proliferation and migration through MTT and Matrigel assay. Results: We then focused on changes in the cytoskeletal components as FN1, actin, and anti angiogenic compounds as TGF-β1 and THBS1. The upregulation of these products may have an important role in inhibiting proliferation, invasion and angiogenesis mediated by ZOL. Conclusions: In conclusion, in the present studies, we investigated the role of ZOL in the regulation of breast cancer cell invasion. Our results demonstrated that ZOL, via cytoskeletal remodelling, plays an inhibitory role in breast cancer cell invasion, possibly by specifically up-regulating the TGF- β1/Smad signaling pathway, and the downstream activity of FN1 and ACTIN

MicroRNAs in colorectal cancer stem cells: new regulators of cancer stemness?

Recently, the hypothesis that colorectal tumors originate from a subpopulation of cells called 'cancer stem cells' (CSCs) or tumor-initiating cells, which exhibit stem-like features, has been confirmed experimentally in various human cancers. Several studies have confirmed the existence of colorectal CSCs (CRCSCs) and have demonstrated that this rare cell population can be isolated by the expression of specific cell surface biomarkers. MicroRNAs (miRNAs) are a class of small non-coding RNAs, which are crucial for post-transcriptional regulation of gene expression and participate in a wide variety of biological functions, including development, cell proliferation, differentiation, metabolism and signal transduction. Moreover, new evidences suggest that miRNAs could contribute to preserve stemness of embryonic stem cells and could be involved in maintaining stemness of CSCs. Recent studies have begun to outline the role of miRNAs in regulation of CRCSCs. This review aims to summarize the recent advancement about the roles of miRNAs in CRCSCs that may represent a step forward in understanding the molecular mechanisms and the possible approaches for colorectal cancer therapy

Analysis of molecular mechanisms and anti-tumoural effects of zoledronic acid in breast cancer cells

Zoledronic acid (ZOL) is the most potent nitrogen-containing bisphosphonate (N-BPs) that strongly binds to bone mineral and acts as a powerful inhibitor of bone resorption, already clinically available for the treatment of patients with osteolytic metastases. Recent data also suggest that ZOL, used in breast cancer, may provide more than just supportive care modifying the course of the disease, though the possible molecular mechanism of action is still unclear. As breast cancer is one of the primary tumours with high propensity to metastasize to the bone, we investigated, for the first time, differential gene expression profile on Michigan Cancer Foundation-7 (MCF-7) breast cancer cells treated with low doses of ZOL (10 lM). Microarrays analysis was used to identify, describe and summarize evidence regarding the molecular basis of actions of ZOL and of their possible direct anti-tumour effects. We validated gene expression results of specific transcripts involved in major cellular process by Real Time and Western Blot analysis and we observed inhibition of proliferation and migration through 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) and Matrigel assay. We then focused on changes in the cytoskeletal components as fibronectin 1 (FN1), actin, and anti angiogenic compounds as transforming growth factor-b1 (TGF-b1) and thrombospondin 1 (THBS1). The up-regulation of these products may have an important role in inhibiting proliferation, invasion and angiogenesis mediated by ZOL

Effects of PPARγ agonists on the expression of leptin and vascular endothelial growth factor in breast cancer cells.

The obesity hormone leptin has been implicated in breast cancer development. Breast cancer cells express the leptin receptor and are able to synthesize leptin in response to obesity-related stimuli. Furthermore, leptin is a positive regulator of vascular endothelial growth factor (VEGF) and high levels of both proteins are associated with worse prognosis in breast cancer patients. Peroxisome proliferator-activated receptor (PPAR) ligands are therapeutic agents used in patient with Type 2 diabetes and obesity which have recently been studied for their potential anti-tumor effect. Here, we studied if these compounds, ciglitazone and GW1929, can affect the expression of leptin and VEGF in breast cancer cells. In MDA-MB-231 and MCF-7 breast cancer cells, treatment with submolar concentrations of ciglitazone and GW1929 elevated the expression of leptin and VEGF mRNA and protein, and increased cell viability and migration. These effects coincided with increased recruitment of PPAR to the proximal leptin promoter and decreased association of a transcriptional factor Sp1 with this DNA region

Non-Small Cell Lung Cancer Harboring Concurrent EGFR Genomic Alterations: A Systematic Review and Critical Appraisal of the Double Dilemma

The molecular pathways which promote lung cancer cell features have been broadly explored, leading to significant improvement in prognostic and diagnostic strategies. Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have dramatically altered the treatment approach for patients with metastatic non-small cell lung cancer (NSCLC). Latest investigations by using next-generation sequencing (NGS) have shown that other oncogenic driver mutations, believed mutually exclusive for decades, could coexist in EGFR-mutated NSCLC patients. However, the exact clinical and pathological role of concomitant genomic aberrations needs to be investigated. In this systematic review, we aimed to summarize the recent data on the oncogenic role of concurrent genomic alterations, by specifically evaluating the characteristics, the pathological significance, and their potential impact on the treatment approach

Aurora-A transcriptional silencing and Vincristine treatment show a synergistic effect in human tumor cells

Aurora-A is a centrosome-associated serine/threonine kinase that is overexpressed in multiple types of human tumors. Primarily, Aurora-A functions in centrosome maturation and mitotic spindle assembly. Overexpression of Aurora-A induces centrosome amplification and G(2)/M cell-cycle progression. Recently, it was observed that overexpression of Aurora-A renders cells resistant to cisplatin (CDDP)-, etoposide, and paclitaxel-induced apoptosis. Our results indicate that already in initial stages of cancer progression Aurora-A overexpression could have a major role in inducing supernumerary centrosomes and aneuploidy, as shown by immunohistochemistry on tissue sections from various stages of human colon cancer. Aneuploidy was also observed after Aurora-A ectopic overexpression in colon cancer cells with MIN phenotype. Silencing of Aurora-A by RNA interference in tumor cell lines triggered arrest of the cell cycle associated to apoptosis/mitotic catastrophe. Finally, Aurora-A transcriptional silencing seems to confer cancer cells a greater sensitivity to chemotherapy by vincristine, indicating Aurora-A as a possible gene target in cancer therapy

EFFECT OF miR-21, miR-182 AND let-7i ON TSP-1 EXPRESSION IN COLON CANCER CELL LINE

Background: MicroRNAs (miRNAs) are small non-coding RNAs that regulate the expression of different genes, including genes involved in cancer progression, angiogenesis and metastasis. Thrombospondin-1 (TSP-1) has been shown to contrast angiogenesis in vivo. TSP-1 expression levels are inversely correlated with tumor vascularity and metastasis in colon cancer. Bio-informatic statistical analysis indicated that TSP-1 is hypothetical target of miR-21, miR-182, overexpressed in CRC, and let-7i which expression is down-regulated in this tumor. In this work we investigated whether TSP-1 expression could be regulated by miR-21, mir-182 and let-7i in HT29 colon cancer cell line. Methods: To investigated whether miR-21, mir-182 and let-7i directly modulates TSP-1 expression, we transfected HT29 cell line with pre-mir21, pre-mir182 and pre-let7i by using siPortNeo FX tranfection agent and after 48h we evaluated TSP-1 mRNA, using Quantitative Real Time-PCR, and intracellular and secreted protein level performed by Western blotting and ELISA. To confirm the modulation of TSP-1 by miRNAs we transfected HT29 cell line with anti-mir to target the mature form of miR-21, miR182 and let-7i. Results: Using Real-Time PCR we did not find any variation of TSP-1 mRNA expression levels after transfection with pre-mir21 in HT29 cell line, but we observed a down-regulation of cytosolic and secreted protein by Western blot and ELISA. In cells transfected with pre-mir182 we did not observe any down-regulation both TSP-1 mRNA and cytosolic and secreted protein. Finally, we did not find any variation of TSP-1 level in cells transfected with let- 7i. Results were confirmed by transfection with anti-mir21, anti- mir182 and anti-let7i and, using the same method, we evaluated TSP-1 expression. Conclusions: Data suggest that mir-182 induces degradation of TSP-1 mRNA in HT29 cell line, whereas mir-21 affects probably by blockage of TSP-1 translation. Let-7i does not seem involved in regulation of TSP-1 expression in HT29 cells. Understanding the molecular mechanism by which miRNAs regulate TSP-1 expression could be used to restore TSP-1 expression to contrast angiogenic events in colon cancer