bafilomycin-a1 and Neoplasm-Metastasis

High-grade serous ovarian carcinoma (HGSOC) is the most lethal type of gynecologic malignancy. Chemoresistance is the main reason for the poor prognosis of HGSOC. PDZ-binding kinase (PBK) promotes the malignant progression of various carcinomas. However, the roles and clinical significance of PBK in HGSOC remain unclear. Here, we reported that PBK was overexpressed in HGSOC tissues and cell lines. High PBK expression was associated with a poor prognosis, metastasis, and cisplatin resistance of HGSOC. Overexpression of PBK promoted autophagy and enhanced cisplatin resistance via the ERK/mTOR signaling pathway. Further study showed that inhibition of autophagy by chloroquine or bafilomycin A1 reversed PBK-induced cisplatin resistance. Overexpression of PBK decreased ovarian cancer responsiveness to cisplatin treatment through inducing autophagy in vivo. We also demonstrated that the PBK inhibitor OTS514 augmented the growth inhibition effect of cisplatin in vitro and in vivo. Moreover, ecotropic viral integration site-1 (EVI1) could regulate PBK expression through directly targeting the PBK promoter region. In conclusion, high PBK expression was correlated with a poor prognosis, metastasis, and cisplatin resistance through promoting autophagy in HGSOC. PBK might be a promising target for the early diagnosis and individual treatment of ovarian cancer.

Topics: Antineoplastic Agents; Apoptosis; Autophagy; Cell Line, Tumor; Cell Movement; Chloroquine; Cisplatin; Drug Resistance, Neoplasm; Female; Gene Expression Regulation, Neoplastic; HEK293 Cells; Humans; Macrolides; MAP Kinase Signaling System; MDS1 and EVI1 Complex Locus Protein; Middle Aged; Mitogen-Activated Protein Kinase Kinases; Neoplasm Metastasis; Ovarian Neoplasms; Prognosis; Retrospective Studies; Signal Transduction; TOR Serine-Threonine Kinases

Molecular alterations that confer phenotypic advantages to tumors can also expose specific therapeutic vulnerabilities. To search for potential treatments that would selectively affect metastatic cells, we examined the sensitivity of lineage-related human bladder cancer cell lines with different lung colonization abilities to chloroquine (CQ) or bafilomycin A

Topics: Animals; Cell Line, Tumor; Chloroquine; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; Humans; Inhibitor of Differentiation Proteins; Lung Neoplasms; Lysosomes; Macrolides; Mice; Neoplasm Metastasis; Neoplasm Proteins; Urinary Bladder Neoplasms

(Pro)renin receptor ((P)RR) is a specific receptor for renin and prorenin. The aim of the present study is to clarify expression of (P)RR and pathophysiological roles of (P)RR in human breast carcinomas. (P)RR expression was studied in 69 clinical cases of breast carcinoma by immunohistochemistry.Effects of (P)RR on cell proliferation were examined in cultured human breast carcinoma cells using (P)RR specific small interference RNA. Immunohistochemistry showed that(P)RR immunoreactivity was detected in the breast carcinoma cells in 50 of 69 cases of breast carcinoma (72%). The analysis on association between (P)RR immunoreactivity and clinicopathological parameters showed that the number of (P)RR positive cases was significantly greater in Ki-67 (a cell proliferation marker)≥10% group than in Ki-67<10% group (P=0.02). (P)RR was expressed in 4 types of human breast carcinoma cell lines. (P)RR specific small interference RNA inhibited proliferation of both MCF-7 (ERα positive) and SK-BR-3 (ERα negative) cells. The present study has shown, for the first time, the expression of (P)RR in human breast carcinoma tissues and cultured breast carcinoma cell lines. These findings have raised the possibility that the blockade of the (P)RR signaling may be a novel therapeutic strategy against breast carcinomas.

Topics: Adult; Aged; Angiotensin II; Biomarkers, Tumor; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Female; Gene Expression; Humans; Immunohistochemistry; Macrolides; Middle Aged; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Neoplasm Grading; Neoplasm Invasiveness; Neoplasm Metastasis; Neoplasm Staging; Phosphorylation; Receptors, Cell Surface; Renin; Risk Factors; RNA Interference; Vacuolar Proton-Translocating ATPases

The pro-apoptotic protein Bnip3 is induced by hypoxia and is present in the core regions of most solid tumors. Bnip3 induces programmed necrosis by an intrinsic caspase independent mitochondrial pathway. Many tumor cells have evolved pathways to evade Bnip3-mediated death attesting to the physiological relevance of the survival threat imposed by Bnip3. We have reported that acidosis can trigger the Bnip3 death pathway in hypoxic cells therefore we hypothesized that manipulation of intracellular pH by pharmacological inhibition of the vacuolar (v)ATPase proton pump, a significant pH control pathway, may activate Bnip3 and promote death of hypoxic cells within the tumor. Here we confirm that bafilomycin A1 (BafA1), a selective vATPase inhibitor, significantly increased death of breast cancer cells in a hypoxia and Bnip3-dependent manner and significantly reduced tumor growth in MCF7 and MDA-MB-231 mouse xenografts. Combined treatment of cells with BafA1 and the ERK1/2 inhibitor U0126 further augmented cell death. Combined treatment of mice containing MDA-MB-231 xenografts with BafA1 and the ERK1/2 inhibitor sorafenib was superior to either treatment alone and supported tumor regression. BafA1 and sorafenib treatments alone reduced MDA-MB-231 cell metastasis and again the combination was significantly more effective than either treatment alone and was without apparent side effects. These results present a novel mechanism to destroy hypoxic tumor cells that may help reverse the resistance of hypoxic tumors to radiation and chemotherapy and perhaps target tumor stem cells.

Topics: Animals; Antineoplastic Agents; Apoptosis; Breast Neoplasms; Butadienes; Cell Hypoxia; Enzyme Inhibitors; Gene Knockdown Techniques; Heterografts; Humans; Hydrogen-Ion Concentration; Macrolides; MAP Kinase Signaling System; MCF-7 Cells; Membrane Proteins; Mice; Neoplasm Metastasis; Niacinamide; Nitriles; Phenylurea Compounds; Proto-Oncogene Proteins; Sorafenib; Tumor Burden; Vacuolar Proton-Translocating ATPases

Human metastatic breast cancer cells in culture contain large acidic vesicles (diameter 5-10 microns) in which endocytosed extracellular matrix can be digested by activated lysosomal proteinases such as cathepsin D (P. Montcourrier et al. (1990). Cancer Res. 50, 6045-6054). We examined these large compartments by transmission electron microscopy, measured their pH by video-enhanced epifluorescence using FITC-dextran, and studied their functional significance. Their presence in metastatic MDA-MB231 cells was found to be correlated with an increased ability of cells to migrate through Matrigel and a high cathepsin D concentration. These cells were able to phagocytose 1.24 microns diameter latex beads and fluorescence Matrigel and incorporate this extracellular material into large acidic vesicles. This indicated that large acidic vesicles were associated with both phagocytosis and invasion, and are heterophagolysosomes rather than autophagosomes. Large acidic vesicles were actively acidified with a H(+)-ATPase vacuolar pump specifically inhibited by bafilomycin A1, and reached pH values (< 4), lower than the lysosomal value (pH approximately 5) in the same cells and in specialized phagocytotic cells such as macrophages. We conclude that the phagocytotic activity of breast cancer cells, associated with high cathepsin D expression, and high acidification potential, characterize cancer cells that have migrated through Matrigel.

Topics: Anti-Bacterial Agents; Breast Neoplasms; Cathepsin D; Cell Movement; Cell Separation; Collagen; Drug Combinations; Endocytosis; Extracellular Matrix; Flow Cytometry; Humans; Hydrogen-Ion Concentration; Laminin; Macrolides; Microscopy, Electron; Microscopy, Fluorescence; Neoplasm Invasiveness; Neoplasm Metastasis; Neoplasm Proteins; Phagocytosis; Phagosomes; Proteoglycans; Proton-Translocating ATPases; Tumor Cells, Cultured; Vacuoles; Videotape Recording