Adenoviral-mediated mda-7 expression suppresses DNA repair capacity and radiosensitizes non-small-cell lung cancer cells

Nishikawa, Takashi; Munshi, Anupama; Story, Michael D.; Ismail, Sheikh M.; Stevens, Craig W.; Chada, Sunil; Meyn, Raymond E.

doi:10.1038/sj.onc.1207917

Cited by 25 publications

(23 citation statements)

References 37 publications

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“…Differences in tumor size were analyzed for significance by the Student's t-test. Enhanced in vitro growth inhibitory and cytotoxic activity of Ad-mda7 and Herceptin in Her-2 þ breast cancer cells The antiproliferative effects of Ad-mda7 in various cancer cell types have been demonstrated in previous studies; [16][17][18][19][20][21][22][24][25][26][27][28][29][30][31][32][33][34]36 and the relevance of these findings to the clinical setting is supported by in vivo lung and breast xenograft models. 17,21 To corroborate that the Her-2 receptors expressed by the breast cancer cells are functional, we evaluated cell death in MDA-MB-453 and MCF-7 lines treated with increasing amounts of Herceptin (0-100 mg/ ml).…”

Section: Discussionmentioning

confidence: 82%

“…[18][19][20][21][22][23]38 It is now known that mda-7 activates various signaling pathways in a cell-type-specific manner, and that these pathways ultimately converge on mitochondrial destruction and induction of apoptosis. 21,22,[24][25][26][27][28][29][30] However, in spite of its clear tumor-suppressive effects, the mechanisms by which Ad-mda7 induces cytotoxicity have not been fully characterized. Our group has previously demonstrated that Ad-mda7, as a single agent therapy, induces apoptosis and inhibits growth in pancreatic, lung and breast cancer cells.…”

Section: Introductionmentioning

confidence: 99%

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Combinatorial synergy induced by adenoviral-mediated mda-7 and Herceptin in Her-2+ breast cancer cells

et al. 2006

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The melanoma differentiation-associated gene-7 (mda-7) is a member of the interleukin-10 cytokine family and a novel tumor suppressor gene. Adenoviral-mediated mda-7 (Ad-mda7) gene transfer has tumor-specific growth inhibitory and proapoptotic effects in a broad spectrum of cancer cells. In breast cancer cells, adenoviral-induced mda-7 expression triggers antiproliferative effects by downregulation of survival signals, such as Bcl-2 and Akt. The anti-human epidermal growth factor receptor-2 (Her-2) monoclonal antibody, Trastuzumab (Herceptin), increases the sensitivity of Her-2/neu-overexpressing breast cancer cells to chemotherapeutic agents and radiotherapy. In this study, we evaluate the effects of treatment with Ad-mda7 and Herceptin combination therapy in a panel of Her-2/neu-overexpressing cell lines, and in established tumors in nude mice. Compared to individual treatments, the combination of Ad-mda7 and Herceptin elicits supra-additive antitumor activity in Her-2/neuoverexpressing tumor cell lines: increased cell death, cell cycle block and apoptosis. The Ad-mda7 and Herceptin interaction was shown to be synergistic by isobologram analysis. Ad-mda7 does not alter cell surface Her-2/neu levels, but the combination of Ad-mda7 þ Herceptin results in increased expression of cell surface E-cadherin with concomitant translocation of b-catenin from the nucleus to the cell membrane. In vivo, the combination of Ad-mda7 and Herceptin showed significantly increased antitumor activity (Po0.003) against Her-2/neu-overexpressing tumors. These data suggest that the combination of Ad-mda7 with Herceptin may be a novel therapy for breast cancer patients whose tumors overexpress Her-2/neu. The observed synergistic effect may improve treatment options for otherwise poorly responsive, Her-2-positive, breast cancer patients. Cancer Gene Therapy (2006) 13, 958-968.

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Section: Discussionmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Combinatorial synergy induced by adenoviral-mediated mda-7 and Herceptin in Her-2+ breast cancer cells

et al. 2006

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“…We updated this relatively old approach (20) to incorporate expression of a reporter gene as the readout; radiation-induced DNA lesions in the reporter gene must be repaired by the host cell with complete fidelity in order for functional gene expression to be restored. We have shown previously that this modified assay detects deficiencies in cellular DSB repair capacity (21). The results of our host cell reactivation assays (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…The adenoviral vector required a high dose of radiation because of its small genome size compared with a mammalian cell. Our calculations indicate that 4,000 Gy should induce about 1 to 2 DSBs/vector particle (21). This is based on the target size of the vector genome (3.5 Â 10 4 bp) versus that of the mammalian cell (3 Â 10 9 bp) and using the value of 35 for the DSBs induced per Gy in the mammalian genome.…”

Section: Methodsmentioning

confidence: 99%

Histone Deacetylase Inhibitors Radiosensitize Human Melanoma Cells by Suppressing DNA Repair Activity

Munshi¹,

Kurland²,

Nishikawa³

et al. 2005

Clinical Cancer Research

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315

285

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Purpose: Histone deacetylase (HDAC) inhibitors have emerged recently as promising anticancer agents. They arrest cells in the cell cycle and induce differentiation and cell death. The antitumor activity of HDAC inhibitors has been linked to their ability to induce gene expression through acetylation of histone and nonhistone proteins. However, it has recently been suggested that HDAC inhibitors may also enhance the activity of other cancer therapeutics, including radiotherapy. The purpose of this study was to evaluate the ability of HDAC inhibitors to radiosensitize human melanoma cells in vitro. Experimental Design: A panel of HDAC inhibitors that included sodium butyrate (NaB), phenylbutyrate, tributyrin, and trichostatin A were tested for their ability to radiosensitize two human melanoma cell lines (A375 and MeWo) using clonogenic cell survival assays. Apoptosis and DNA repair were measured by standard assays. Results: NaB induced hyperacetylation of histone H4 in the two melanoma cell lines and the normal human fibroblasts. NaB radiosensitized both the A375 and MeWo melanoma cell lines, substantially reducing the surviving fraction at 2 Gy (SF2), whereas it had no effect on the normal human fibroblasts. The other HDAC inhibitors, phenylbutyrate, tributyrin, and trichostatin A had significant radiosensitizing effects on both melanoma cell lines tested. NaB modestly enhanced radiation-induced apoptosis that did not correlate with survival but did correlate with functional impairment of DNA repair as determined based on the host cell reactivation assay. Moreover, NaB significantly reduced the expression of the repair-related genes Ku70 and Ku86 and DNA-dependent protein kinase catalytic subunit in melanoma cells at the protein and mRNA levels. Normal human fibroblasts showed no change in DNA repair capacity or levels of DNA repair proteins following NaB treatment. We also examined g-H2AX phosphorylation as a marker of radiation response to NaB and observed that compared with controls, g-H2AX foci persisted long after ionizing exposure in the NaB-treated cells. Conclusions: HDAC inhibitors radiosensitize human tumor cells by affecting their ability to repair the DNA damage induced by ionizing radiation and that g-H2AX phosphorylation can be used as a predictive marker of radioresponse.

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“…To detect high molecular weight DNA fragmentation, genomic DNA in the CO-3 tumor cells was extracted and purified using a Get pure DNA kit, loaded with exactly 1.2% agarose and 10 µg of DNA in each well; the DNA was then separated using pulse field gel electrophoresis (PFGE) using a CHEF-DR II system (Bio-Rad Laboratories, Tokyo, Japan) at 1.5 V/cm for 20 h at 25˚C in 0.5X TBE buffer as previously described (11). A comparison of the DNA concentrations among the different samples was performed using ethidium bromide staining.…”

Section: Methodsmentioning

confidence: 99%

Trifluorothymidine exhibits potent antitumor activity via the induction of DNA double-strand breaks

Suzuki

Nakagawa

Nukatsuka

et al. 2011

Experimental and Therapeutic Medicine

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Abstract. taS-102 is an oral anticancer drug composed of trifluorothymidine (TFT) and TPI (an inhibitor of thymidine phosphorylase that strongly inhibits the biodegradation of TFT). Similar to 5-fluorouracil (5FU) and 5-fluoro-2'-deoxyuridine (FdUrd), TFT also inhibits thymidylate synthase (TS), a rate-limiting enzyme of DNA biosynthesis, and is incorporated into DNA. TFT exhibits an anticancer effect on colorectal cancer cells that have acquired 5FU and/or FdUrd resistance as a result of the overexpression of TS. Therefore, we examined the mode of action of TFT-induced DNA damage after its incorporation into DNA. When HeLa cells were treated with TFT, the number of ring-open aldehyde forms at apurinic/apyrimidinic sites increased in a dose-dependent manner, although we previously reported that no detectable excisions of TFT paired to adenine were observed using uracil DNA glycosylases, thymine DNA glycosylase or methyl-CpG binding domain 4 and HeLa whole cell extracts. To investigate the functional mechanism of TFT-induced DNA damage, we measured the phosphorylation of ATR, ATM, BRCA2, chk1 and chk2 in nuclear extracts of HeLa cells after 0, 24, 48 or 72 h of exposure to an IC 50 concentration of TFT, FdUrd or 5FU using Western blot analysis or an enzyme-linked immunosorbent assay (ELISA). Unlike FdUrd and 5FU, TFT resulted in an earlier phosphorylation of ATR and chk1 proteins after only 24 h of exposure, while phosphorylated ATM, BRCA2 and chk2 proteins were detected after more than 48 h of exposure to TFT. These results suggest that TFT causes singlestrand breaks followed by double-strand breaks in the DNA of TFT-treated cells. TFT (as TAS-102) showed a more potent antitumor activity than oral 5FU on CO-3 colon cancer xenografts in mice, and such antitumor potency was supported by the increased number of double-strand breaks occurring after single-strand breaks in the DNA of the TFT-treated tumors.These results suggest that TFT causes single-strand breaks after its incorporation into DNA followed by double-strand breaks, resulting in DNA damage. This effect of TFT on DNA may explain its potent anticancer activity in cancer therapy.

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Adenoviral-mediated mda-7 expression suppresses DNA repair capacity and radiosensitizes non-small-cell lung cancer cells

Cited by 25 publications

References 37 publications

Combinatorial synergy induced by adenoviral-mediated mda-7 and Herceptin in Her-2+ breast cancer cells

Combinatorial synergy induced by adenoviral-mediated mda-7 and Herceptin in Her-2+ breast cancer cells

Histone Deacetylase Inhibitors Radiosensitize Human Melanoma Cells by Suppressing DNA Repair Activity

Trifluorothymidine exhibits potent antitumor activity via the induction of DNA double-strand breaks

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