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The novel histone deacetylase inhibitor, N-hydroxy-7-(2-naphthylthio) hepatonomide, exhibits potent antitumor activity due to cytochrome-c-release-mediated apoptosis in renal cell carcinoma cells.

Park KC, Heo JH, Jeon JY, Choi HJ, Jo AR, Kim SW, Kwon HJ, Hong SJ, Han KS - BMC Cancer (2015)

Bottom Line: Renal tumors have been shown to have a higher global methylation percentage and reduced histone acetylation.An in vivo study showed that HNHA had greater anti-tumor and pro-apoptotic effects on RCC xenografts than the established HDAC inhibitors.These results suggest that HNHA may offer a new therapeutic approach to RCC.

View Article: PubMed Central - PubMed

ABSTRACT

Background: Epigenetic modifications play a critical role in the regulation of all DNA-based processes, such as transcription, repair, and replication. Inappropriate histone modifications can result in dysregulation of cell growth, leading to neoplastic transformation and cell death. Renal tumors have been shown to have a higher global methylation percentage and reduced histone acetylation. Preclinical models have revealed that histone gene modifiers and epigenetic alterations play important roles in renal cell carcinoma (RCC) tumorigenesis. Recently, a novel HDAC inhibitor, N-hydroxy-7-(2-naphthylthio) heptanomide (HNHA), has been introduced as an example of a new class of anti-cancer agents. The anti-cancer activity of HNHA and the underlying mechanisms of action remain to be clarified.

Methods: The MTS assay using a panel of RCC cells was used to evaluate the anti-proliferative effects of HNHA. The established HDAC inhibitors, SAHA and TSA, were used for comparison. Western blotting analysis was performed to investigate the acetylation of histone H3 and the expression of apoptotic markers in vitro and in vivo. Subcellular fractionation was performed to evaluate expression of Bax and cytochrome c in the cytosol and mitochondria, and also translocation of cytochrome c from the cytoplasm to the nucleus. A confocal microscopic evaluation was performed to confirm inhibition of cell proliferation, induction of apoptosis, and the nuclear translocation of cytochrome c in RCC cells.

Results: In this study, we investigated the apoptosis-inducing activity of HNHA in cultured kidney cancer cells. Apoptosis in the HNHA-treated group was induced significantly, with marked caspase activation and Bcl-2 suppression in RCC cells in vitro and in vivo. HNHA treatment caused cytochrome c release from mitochondria, which was mediated by increased Bax expression and caspase activation. HNHA also induced nuclear translocation of cytochrome c, suggesting that HNHA can induce caspase-independent nuclear apoptosis in RCC cells. An in vivo study showed that HNHA had greater anti-tumor and pro-apoptotic effects on RCC xenografts than the established HDAC inhibitors.

Conclusions: HNHA has more potent anti-tumor activity than established HDAC inhibitors. Its activities are mediated by caspase-dependent and cytochrome-c-mediated apoptosis in RCC cells. These results suggest that HNHA may offer a new therapeutic approach to RCC.

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HNHA induced cytochrome c-dependent, caspase-dependent apoptotic death in RCCs. Subcellular fractionation showed that the Bax level was increased, and cytochrome c release into the cytosol was enhanced by HNHA, in Caki-1 (A) and A 498 cells (B). Immunofluorescent cytochemical staining showed that cytochrome c was translocated and accumulated in the nucleus, suggesting that HNHA induced apoptosis through a cytochrome-c-dependent pathway. (C, D) Western blot analysis after subcellular fractionation confirmed that cytochrome c was translocated into the nucleus after HNHA treatment (E, F).
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Fig5: HNHA induced cytochrome c-dependent, caspase-dependent apoptotic death in RCCs. Subcellular fractionation showed that the Bax level was increased, and cytochrome c release into the cytosol was enhanced by HNHA, in Caki-1 (A) and A 498 cells (B). Immunofluorescent cytochemical staining showed that cytochrome c was translocated and accumulated in the nucleus, suggesting that HNHA induced apoptosis through a cytochrome-c-dependent pathway. (C, D) Western blot analysis after subcellular fractionation confirmed that cytochrome c was translocated into the nucleus after HNHA treatment (E, F).

Mentions: DNA damage induces apoptosis by release of cytochrome c from mitochondria. To assess the mechanisms of HNHA-induced apoptosis, we next evaluated the expression of cytochrome c and caspases using immunofluorescence and Western blotting. Subcellular fractionation demonstrated that the HDAC inhibitors activated the mitochondrial pathway of apoptosis, characterized by the translocation of Bax (a proapoptotic Bcl-2 protein) from the cytosol to the mitochondria and the release of cytochrome c from the mitochondria into the cytosol in Caki-1 and A-498 cells (Figure 5A, B). Immunofluorescent cytochemical staining showed that cytochrome c was translocated and accumulated in the nucleus, suggesting that HNHA induces apoptosis through a cytochrome-c-dependent pathway (Figure 5C, D). Western blot analysis after subcellular fractionation that confirmed cytochrome c was translocated into the nucleus after HNHA treatment (Figure 5E, F). In summary, these results suggest that apoptosis is induced by HNHA through caspase- and cytochrome-c-dependent pathways in RCC cells.Figure 5


The novel histone deacetylase inhibitor, N-hydroxy-7-(2-naphthylthio) hepatonomide, exhibits potent antitumor activity due to cytochrome-c-release-mediated apoptosis in renal cell carcinoma cells.

Park KC, Heo JH, Jeon JY, Choi HJ, Jo AR, Kim SW, Kwon HJ, Hong SJ, Han KS - BMC Cancer (2015)

HNHA induced cytochrome c-dependent, caspase-dependent apoptotic death in RCCs. Subcellular fractionation showed that the Bax level was increased, and cytochrome c release into the cytosol was enhanced by HNHA, in Caki-1 (A) and A 498 cells (B). Immunofluorescent cytochemical staining showed that cytochrome c was translocated and accumulated in the nucleus, suggesting that HNHA induced apoptosis through a cytochrome-c-dependent pathway. (C, D) Western blot analysis after subcellular fractionation confirmed that cytochrome c was translocated into the nucleus after HNHA treatment (E, F).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4318161&req=5

Fig5: HNHA induced cytochrome c-dependent, caspase-dependent apoptotic death in RCCs. Subcellular fractionation showed that the Bax level was increased, and cytochrome c release into the cytosol was enhanced by HNHA, in Caki-1 (A) and A 498 cells (B). Immunofluorescent cytochemical staining showed that cytochrome c was translocated and accumulated in the nucleus, suggesting that HNHA induced apoptosis through a cytochrome-c-dependent pathway. (C, D) Western blot analysis after subcellular fractionation confirmed that cytochrome c was translocated into the nucleus after HNHA treatment (E, F).
Mentions: DNA damage induces apoptosis by release of cytochrome c from mitochondria. To assess the mechanisms of HNHA-induced apoptosis, we next evaluated the expression of cytochrome c and caspases using immunofluorescence and Western blotting. Subcellular fractionation demonstrated that the HDAC inhibitors activated the mitochondrial pathway of apoptosis, characterized by the translocation of Bax (a proapoptotic Bcl-2 protein) from the cytosol to the mitochondria and the release of cytochrome c from the mitochondria into the cytosol in Caki-1 and A-498 cells (Figure 5A, B). Immunofluorescent cytochemical staining showed that cytochrome c was translocated and accumulated in the nucleus, suggesting that HNHA induces apoptosis through a cytochrome-c-dependent pathway (Figure 5C, D). Western blot analysis after subcellular fractionation that confirmed cytochrome c was translocated into the nucleus after HNHA treatment (Figure 5E, F). In summary, these results suggest that apoptosis is induced by HNHA through caspase- and cytochrome-c-dependent pathways in RCC cells.Figure 5

Bottom Line: Renal tumors have been shown to have a higher global methylation percentage and reduced histone acetylation.An in vivo study showed that HNHA had greater anti-tumor and pro-apoptotic effects on RCC xenografts than the established HDAC inhibitors.These results suggest that HNHA may offer a new therapeutic approach to RCC.

View Article: PubMed Central - PubMed

ABSTRACT

Background: Epigenetic modifications play a critical role in the regulation of all DNA-based processes, such as transcription, repair, and replication. Inappropriate histone modifications can result in dysregulation of cell growth, leading to neoplastic transformation and cell death. Renal tumors have been shown to have a higher global methylation percentage and reduced histone acetylation. Preclinical models have revealed that histone gene modifiers and epigenetic alterations play important roles in renal cell carcinoma (RCC) tumorigenesis. Recently, a novel HDAC inhibitor, N-hydroxy-7-(2-naphthylthio) heptanomide (HNHA), has been introduced as an example of a new class of anti-cancer agents. The anti-cancer activity of HNHA and the underlying mechanisms of action remain to be clarified.

Methods: The MTS assay using a panel of RCC cells was used to evaluate the anti-proliferative effects of HNHA. The established HDAC inhibitors, SAHA and TSA, were used for comparison. Western blotting analysis was performed to investigate the acetylation of histone H3 and the expression of apoptotic markers in vitro and in vivo. Subcellular fractionation was performed to evaluate expression of Bax and cytochrome c in the cytosol and mitochondria, and also translocation of cytochrome c from the cytoplasm to the nucleus. A confocal microscopic evaluation was performed to confirm inhibition of cell proliferation, induction of apoptosis, and the nuclear translocation of cytochrome c in RCC cells.

Results: In this study, we investigated the apoptosis-inducing activity of HNHA in cultured kidney cancer cells. Apoptosis in the HNHA-treated group was induced significantly, with marked caspase activation and Bcl-2 suppression in RCC cells in vitro and in vivo. HNHA treatment caused cytochrome c release from mitochondria, which was mediated by increased Bax expression and caspase activation. HNHA also induced nuclear translocation of cytochrome c, suggesting that HNHA can induce caspase-independent nuclear apoptosis in RCC cells. An in vivo study showed that HNHA had greater anti-tumor and pro-apoptotic effects on RCC xenografts than the established HDAC inhibitors.

Conclusions: HNHA has more potent anti-tumor activity than established HDAC inhibitors. Its activities are mediated by caspase-dependent and cytochrome-c-mediated apoptosis in RCC cells. These results suggest that HNHA may offer a new therapeutic approach to RCC.

Show MeSH
Related in: MedlinePlus