Epicatechin Stimulates Mitochondrial Activity and Selectively Sensitizes Cancer Cells to Radiation

Radiotherapy is the treatment of choice for solid tumors including pancreatic cancer, but the effectiveness of treatment is limited by radiation resistance. Resistance to chemotherapy or radiotherapy is associated with reduced mitochondrial respiration and drugs that stimulate mitochondrial respiration may decrease radiation resistance. The objectives of this study were to evaluate the potential of (-)-epicatechin to stimulate mitochondrial respiration in cancer cells and to selectively sensitize cancer cells to radiation. We investigated the natural compound (-)-epicatechin for effects on mitochondrial respiration and radiation resistance of pancreatic and glioblastoma cancer cells using a Clark type oxygen electrode, clonogenic survival assays, and Western blot analyses. (-)-Epicatechin stimulated mitochondrial respiration and oxygen consumption in Panc-1 cells. Human normal fibroblasts were not affected. (-)-Epicatechin sensitized Panc-1, U87, and MIA PaCa-2 cells with an average radiation enhancement factor (REF) of 1.7, 1.5, and 1.2, respectively. (-)-Epicatechin did not sensitize normal fibroblast cells to ionizing radiation with a REF of 0.9, suggesting cancer cell selectivity. (-)-Epicatechin enhanced Chk2 phosphorylation and p21 induction when combined with radiation in cancer, but not normal, cells. Taken together, (-)-epicatechin radiosensitized cancer cells, but not normal cells, and may be a promising candidate for pancreatic cancer treatment when combined with radiation

Importin 7 May Be Dispensable for Human Immunodeficiency Virus Type 1 and Simian Immunodeficiency Virus Infection of Primary Macrophages

In an in vitro assay employing reconstituted nuclei, importin 7 (IPO7) has been implicated in nuclear translocation of human immunodeficiency virus type 1 (HIV-1) cDNA. Using RNA interference technology, we inhibited expression of IPO7 by 80 to 95% in primary macrophages and in HeLa cells and monitored their ability to support HIV-1 and simian immunodeficiency virus (SIV) cDNA synthesis, nuclear translocation, and infection efficiency. Marked IPO7 deficiency did not alter the rate or extent of HIV-1 or SIV cDNA synthesis or nuclear translocation. The infection efficiency of HIV-1 was similarly unaltered. Therefore, in natural, nondividing targets of HIV-1, IPO7 may be dispensable for infection

Modest but Reproducible Inhibition of Human Immunodeficiency Virus Type 1 Infection in Macrophages following LEDGFp75 Silencing

LEDGFp75 is a cellular protein which binds human immunodeficiency virus type 1 (HIV-1) integrase with high specificity and affinity but whose function in infection has not been defined. We infected LEDGFp75-deficient primary macrophages with wild-type HIV in order to assess potential infection phenotypes which would provide clues to LEDGFp75 function. Silencing of LEDGFp75 by 70 to 80% resulted in an average of 53% reduced infection of macrophages by HIV. Analysis of infection intermediates showed that integration, but not two-long-terminal-repeat (2LTR) circles or late cDNAs, was reduced up to 74% in LEDGFp75-deficient macrophages. Therefore, LEDGFp75 has a modest involvement in HIV-1 integration in macrophages

Loss of Tumor-Initiating Cell Activity in Cyclophosphamide-Treated Breast Xenografts1

Cancer stem cells (CSCs) are a subpopulation of tumor cells with preferential tumor-initiating capacity and have been purported to be resistant to chemotherapy. It has been shown that breast CSC are, on average, enriched in patient tumors after combination neoadjuvant chemotherapy including docetaxel, doxorubicin, and cyclophosphamide (CPA). Here, we investigate the resistance of breast CSC to CPA alone in a xenograft model. CPA treatment led to a 48% reduction in tumor volume during a 2-week period. Cells bearing the CD44+ CD24- phenotype were reduced by 90% (2.5% to 0.24%) in CPA-treated tumors, whereas cells with aldehyde dehydrogenase activity were reduced by 64% (4.7% to 1.7%). A subsequent functional analysis showed that CPA-treated tumors were impaired in their ability to form tumors, indicating loss of functional tumor-initiating activity. These results are consistent with a CSC phenotype that is sensitive to CPA and indicate that some patient CSC may not display the expected resistance to therapy. Deciphering the mechanism for this difference may lead to therapies to counteract resistance

Ablation of Breast Cancer Stem Cells with Radiation1

Tumor radioresistance leads to recurrence after radiation therapy. The radioresistant phenotype has been hypothesized to reside in the cancer stem cell (CSC) component of breast and other tumors and is considered to be an inherent property of CSC. In this study, we assessed the radiation resistance of breast CSCs using early passaged, patient-derived xenografts from two separate patients. We found a patient-derived tumor in which the CSC population was rapidly depleted 2 weeks after treatment with radiation, based on CD44+ CD24- lin- phenotype and aldehyde dehydrogenase 1 immunofluorescence, suggesting sensitivity to radiotherapy. The reduction in CSCs according to phenotypic markers was accompanied by a decrease in functional CSC activity measured by tumor sphere frequency and the ability to form tumors in mice. In contrast, another patient tumor sample displayed enrichment of CSC after irradiation, signifying radioresistance, in agreement with others. CSC response to radiation did not correlate with the level of reactive oxygen species in CSC versus non-CSC. These findings demonstrate that not all breast tumor CSCs are radioresistant and suggest a mechanism for the observed variability in breast cancer local recurrence

Additional file 4 of SNHG1 opposes quiescence and promotes docetaxel sensitivity in prostate cancer

Additional file 4. Original,full-length images from Western blotting, corresponding to cropped images shownin Fig. 7. SNHG1silencing results in reduced G2phaseand apoptosis markers after DTX treatment. Western blots showing the apoptosismarkers, cleaved caspase 3 and cleaved PARP1, and the G2marker,cyclin B1. β-actin is loading control. For PC3 (A), two separate blotsare shown. For C4-2B (B), a single blot was probed for multipleproteins. Numbers indicate band density versus siCTRL, normalized to β-actin

Additional file 1 of SNHG1 opposes quiescence and promotes docetaxel sensitivity in prostate cancer

Additional file 1. Knockdownof SNHG1reduces DNA synthesis in LNCaPand DU-145 cells. (A) Assessmentof SNHG1knockdown in LNCaPand DU-145 cells. (B) Flow cytometryplot of EdUlabeled cells with or without SNHG1knockdown. (C) Quantitationof the proportion of EdU+cells after transfection with siCTRLor siSNHG1.All graphs depict mean±SD, N=3. Statistical analysis done using Studentt test: *P<0.05; **, P<0.01

Additional file 2 of SNHG1 opposes quiescence and promotes docetaxel sensitivity in prostate cancer

Additional file 2. SNHG1silencing is protective against DTX in LNCaPandDU-145 cells. (A) Representative histograms of PI stained LNCaPandDU-145 with or without SNHG1knockdown and with or without treatment with20 nMDTX. (B) Results of quantitation of apoptotic, G0/G1,S, and G2/Mpopulations in untreated or DTX treated, SNHG1silenced or not, cells.Data represent mean ±SD, N=4. Statistical analysis was done usingStudent’s t test: ns, not significant; *P<0.05; **, P<0.01

Molecular Mechanisms and Therapeutic Effects of (−)-Epicatechin and Other Polyphenols in Cancer, Inflammation, Diabetes, and Neurodegeneration

With recent insight into the mechanisms involved in diseases, such as cardiovascular disease, cancer, stroke, neurodegenerative diseases, and diabetes, more efficient modes of treatment are now being assessed. Traditional medicine including the use of natural products is widely practiced around the world, assuming that certain natural products contain the healing properties that may in fact have a preventative role in many of the diseases plaguing the human population. This paper reviews the biological effects of a group of natural compounds called polyphenols, including apigenin, epigallocatechin gallate, genistein, and (−)-epicatechin, with a focus on the latter. (−)-Epicatechin has several unique features responsible for a variety of its effects. One of these is its ability to interact with and neutralize reactive oxygen species (ROS) in the cell. (−)-Epicatechin also modulates cell signaling including the MAP kinase pathway, which is involved in cell proliferation. Mutations in this pathway are often associated with malignancies, and the use of (−)-epicatechin holds promise as a preventative agent and as an adjunct for chemotherapy and radiation therapy to improve outcome. This paper discusses the potential of some phenolic compounds to maintain, protect, and possibly reinstate health