Restoration of tumor suppressor miR-34 inhibits human p53-mutant gastric cancer tumorspheres
<p>Abstract</p> <p>Background</p> <p>MicroRNAs (miRNAs), some of which function as oncogenes or tumor suppressor genes, are involved in carcinogenesis via regulating cell proliferation and/or cell death. MicroRNA miR-34 was recently found to be a direct target of p53, f...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
BMC
2008-09-01
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| Series: | BMC Cancer |
| Online Access: | http://www.biomedcentral.com/1471-2407/8/266 |
| _version_ | 1818485427295748096 |
|---|---|
| author | DeSano Jeffrey Zhang Min Meng Yang Hao Xinbao Ji Qing Fan Daiming Xu Liang |
| author_facet | DeSano Jeffrey Zhang Min Meng Yang Hao Xinbao Ji Qing Fan Daiming Xu Liang |
| author_sort | DeSano Jeffrey |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>MicroRNAs (miRNAs), some of which function as oncogenes or tumor suppressor genes, are involved in carcinogenesis via regulating cell proliferation and/or cell death. MicroRNA miR-34 was recently found to be a direct target of p53, functioning downstream of the p53 pathway as a tumor suppressor. miR-34 targets Notch, HMGA2, and Bcl-2, genes involved in the self-renewal and survival of cancer stem cells. The role of miR-34 in gastric cancer has not been reported previously. In this study, we examined the effects of miR-34 restoration on p53-mutant human gastric cancer cells and potential target gene expression.</p> <p>Methods</p> <p>Human gastric cancer cells were transfected with miR-34 mimics or infected with the lentiviral miR-34-MIF expression system, and validated by miR-34 reporter assay using Bcl-2 3'UTR reporter. Potential target gene expression was assessed by Western blot for proteins, and by quantitative real-time RT-PCR for mRNAs. The effects of miR-34 restoration were assessed by cell growth assay, cell cycle analysis, caspase-3 activation, and cytotoxicity assay, as well as by tumorsphere formation and growth.</p> <p>Results</p> <p>Human gastric cancer Kato III cells with miR-34 restoration reduced the expression of target genes Bcl-2, Notch, and HMGA2. Bcl-2 3'UTR reporter assay showed that the transfected miR-34s were functional and confirmed that Bcl-2 is a direct target of miR-34. Restoration of miR-34 chemosensitized Kato III cells with a high level of Bcl-2, but not MKN-45 cells with a low level of Bcl-2. miR-34 impaired cell growth, accumulated the cells in G1 phase, increased caspase-3 activation, and, more significantly, inhibited tumorsphere formation and growth.</p> <p>Conclusion</p> <p>Our results demonstrate that in p53-deficient human gastric cancer cells, restoration of functional miR-34 inhibits cell growth and induces chemosensitization and apoptosis, indicating that miR-34 may restore p53 function. Restoration of miR-34 inhibits tumorsphere formation and growth, which is reported to be correlated to the self-renewal of cancer stem cells. The mechanism of miR-34-mediated suppression of self-renewal appears to be related to the direct modulation of downstream targets Bcl-2, Notch, and HMGA2, indicating that miR-34 may be involved in gastric cancer stem cell self-renewal/differentiation decision-making. Our study suggests that restoration of the tumor suppressor miR-34 may provide a novel molecular therapy for p53-mutant gastric cancer.</p> |
| first_indexed | 2024-12-10T16:08:46Z |
| format | Article |
| id | doaj.art-571a359cac34444e8430cc04352be5c5 |
| institution | Directory Open Access Journal |
| issn | 1471-2407 |
| language | English |
| last_indexed | 2024-12-10T16:08:46Z |
| publishDate | 2008-09-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Cancer |
| spelling | doaj.art-571a359cac34444e8430cc04352be5c52022-12-22T01:42:10ZengBMCBMC Cancer1471-24072008-09-018126610.1186/1471-2407-8-266Restoration of tumor suppressor miR-34 inhibits human p53-mutant gastric cancer tumorspheresDeSano JeffreyZhang MinMeng YangHao XinbaoJi QingFan DaimingXu Liang<p>Abstract</p> <p>Background</p> <p>MicroRNAs (miRNAs), some of which function as oncogenes or tumor suppressor genes, are involved in carcinogenesis via regulating cell proliferation and/or cell death. MicroRNA miR-34 was recently found to be a direct target of p53, functioning downstream of the p53 pathway as a tumor suppressor. miR-34 targets Notch, HMGA2, and Bcl-2, genes involved in the self-renewal and survival of cancer stem cells. The role of miR-34 in gastric cancer has not been reported previously. In this study, we examined the effects of miR-34 restoration on p53-mutant human gastric cancer cells and potential target gene expression.</p> <p>Methods</p> <p>Human gastric cancer cells were transfected with miR-34 mimics or infected with the lentiviral miR-34-MIF expression system, and validated by miR-34 reporter assay using Bcl-2 3'UTR reporter. Potential target gene expression was assessed by Western blot for proteins, and by quantitative real-time RT-PCR for mRNAs. The effects of miR-34 restoration were assessed by cell growth assay, cell cycle analysis, caspase-3 activation, and cytotoxicity assay, as well as by tumorsphere formation and growth.</p> <p>Results</p> <p>Human gastric cancer Kato III cells with miR-34 restoration reduced the expression of target genes Bcl-2, Notch, and HMGA2. Bcl-2 3'UTR reporter assay showed that the transfected miR-34s were functional and confirmed that Bcl-2 is a direct target of miR-34. Restoration of miR-34 chemosensitized Kato III cells with a high level of Bcl-2, but not MKN-45 cells with a low level of Bcl-2. miR-34 impaired cell growth, accumulated the cells in G1 phase, increased caspase-3 activation, and, more significantly, inhibited tumorsphere formation and growth.</p> <p>Conclusion</p> <p>Our results demonstrate that in p53-deficient human gastric cancer cells, restoration of functional miR-34 inhibits cell growth and induces chemosensitization and apoptosis, indicating that miR-34 may restore p53 function. Restoration of miR-34 inhibits tumorsphere formation and growth, which is reported to be correlated to the self-renewal of cancer stem cells. The mechanism of miR-34-mediated suppression of self-renewal appears to be related to the direct modulation of downstream targets Bcl-2, Notch, and HMGA2, indicating that miR-34 may be involved in gastric cancer stem cell self-renewal/differentiation decision-making. Our study suggests that restoration of the tumor suppressor miR-34 may provide a novel molecular therapy for p53-mutant gastric cancer.</p>http://www.biomedcentral.com/1471-2407/8/266 |
| spellingShingle | DeSano Jeffrey Zhang Min Meng Yang Hao Xinbao Ji Qing Fan Daiming Xu Liang Restoration of tumor suppressor miR-34 inhibits human p53-mutant gastric cancer tumorspheres BMC Cancer |
| title | Restoration of tumor suppressor miR-34 inhibits human p53-mutant gastric cancer tumorspheres |
| title_full | Restoration of tumor suppressor miR-34 inhibits human p53-mutant gastric cancer tumorspheres |
| title_fullStr | Restoration of tumor suppressor miR-34 inhibits human p53-mutant gastric cancer tumorspheres |
| title_full_unstemmed | Restoration of tumor suppressor miR-34 inhibits human p53-mutant gastric cancer tumorspheres |
| title_short | Restoration of tumor suppressor miR-34 inhibits human p53-mutant gastric cancer tumorspheres |
| title_sort | restoration of tumor suppressor mir 34 inhibits human p53 mutant gastric cancer tumorspheres |
| url | http://www.biomedcentral.com/1471-2407/8/266 |
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