To determine whether oestrogen enhances platinum sensitivity, and if promoter CpG methylation of the oestrogen receptor-alpha (ER-alpha) gene determines the potential of cisplatin-induced apoptosis in prostate cancer, as the high-mobility group 1 (HMG1) preferentially binds to cisplatin-modified DNA and is up-regulated after oestrogen treatment in breast cancer cell line MCF-7.
The study comprised prostate cancer cell lines (LNCaP and PC-3), 156 pathologically confirmed 156 radical prostatectomy samples and eight hormone-refractory prostate cancer (HRPC) samples (from needle biopsy). Expression of HMG1 in cell lines was analysed by Western blotting or differential reverse-transcription-polymerase chain reaction (PCR). The methylation status of ER-alpha was analysed by methylation-specific PCR using bisulphite DNA as a template or bisulphite DNA sequencing.
In LNCaP cells, treatment with oestrogen increased HMG1 expression and co-treatment with cisplatin and oestrogen reduced cell viability by accelerating apoptosis, compared with cisplatin alone. However, in PC-3, oestrogen did not up-regulate HMG1 or accelerate the cisplatin-induced apoptosis. Although ER-beta was expressed in both LNCaP and PC-3, ER-alpha was expressed only in LNCaP. Bisulphite DNA sequencing of the ER-alpha promoter showed partial methylation in LNCaP but complete methylation in PC-3. ER-alpha AS transfection diminished the cisplatin-induced apoptosis in oestrogen-treated LNCaP cells. In clinical samples there was ER-alpha hypermethylation in 40% of prostate cancers this correlated with Gleason score (GS, 31% for GS < 7, 50% for GS = 7 and 56% for GS > 7). In addition, five of eight HRPC samples showed ER-alpha hypermethylation.
These findings suggest that HMG1 induction as an enhancer of platinum sensitivity is mediated through interaction between oestrogen and ER-alpha. As CpG hypermethylation of the ER-alpha promoter is a frequent event in aggressive prostate cancer, negative conversion of ER-alpha methylation is essential to achieve the most beneficial effect when combined chemotherapy of cisplatin with oestrogen is used in patients with prostate cancer.
"Docetaxel in combination with either prednisone or estramustine has been shown to improve the survival only to a small extent . Although there have been many other attempts to develop better tolerated and more effective compounds and combinations for the treatment of prostate cancer, none of these so far displayed any very exciting outcome    . Therefore, the finding that depletion of Kindlin-2 enhances cisplatin-induced PCa cell death may provide a promising target for elevating the effects of chemotherapy for prostate cancer, in particular for hormone refractory prostate cancer. "
[Show abstract][Hide abstract] ABSTRACT: Resistance to anticancer drugs is often observed in prostate cancer therapy. Kindlin-2 was recently found overexpressed during cancer progression. In this study, we examined the functional role of Kindlin-2 in cisplatin-induced prostate cancer cell death. Kindlin-2 was highly expressed in the androgen-insensitive (PC-3 and DU-145), but not in the androgen-sensitive cell lines (e.g., LNCaP). Overexpression of Kindlin-2 in LNCaP protected the cells from cisplatin-induced death, while Kindlin-2 knock-down in PC-3 cells enhanced cisplatin sensitivity. Mechanistically, Kindlin-2 regulation of the anti-apoptotic Bcl-xL may explain the increased cell death in the absence of Kindlin-2. Taken together, Kindlin-2 appears to play a functional role in prostate cancer cell sensitivity to cisplatin. Targeting Kindlin-2 may therefore improve drug efficacy and reduce drug doses, and would likely be beneficial for the treatment of prostate cancer.
Cancer letters 12/2010; 299(1):54-62. DOI:10.1016/j.canlet.2010.08.003 · 5.62 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A novel gene, rat pHyde, has been cloned by us recently. The rat pHyde was shown by the same group to have growth inhibitory effects on human prostate cancer through the induction of apoptosis.
In this report, a human homologue, hpHyde of the rat pHyde, was cloned by cDNA libraries screening. The database search and in situ hybridization were used to map the genomic loci of hpHyde in human chromosome. The anti-prostate cancer effects of pHyde in conjunction with chemotherapy agent were analyzed by in vitro and in vivo assays using adenoviral vector expressing pHyde (AdRSVpHyde) in combination with DNA damaging chemotherapeutic agent, cisplatin, and docetaxel, respectively.
Database search and FISH analysis consistently indicated that hpHyde gene localizes at human chromosome 2q14. Protein sequence analysis suggests that hpHyde may be a plasma membrane protein. hpHyde is differentially expressed in various normal human tissues and organs, suggesting that hpHyde may play roles in development and differentiation. Growth suppression and induction of apoptosis were additively greater in DU145 human prostate cancer cells treated with AdRSVpHyde and cisplatin than either agent alone both in vitro and in vivo. Moreover, AdRSVpHyde and docetaxel also have a similar additively inhibitory effect on DU145 cell growth.
A novel gene hpHyde, the human homologue of rat pHyde, has been cloned and its genomic location in the human chromosome has been identified. Our results support the potential use of pHyde for prostate cancer gene therapy coupled with chemotherapy to improve therapeutic index.
The Prostate 02/2009; 69(3):234-48. DOI:10.1002/pros.20867 · 3.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Promoter hypermethylation is associated with the loss of expression of tumor-suppressor genes in cancer. Currently, several genome-wide technologies are available and have been utilized to examine the extent of DNA methylation in discovery-based studies involving several physiological and disease states. Although early in the process, aberrant DNA methylation is gaining strength in the fields of cancer risk assessment, diagnosis and therapy monitoring in different cancer types. There is a need to improve existing methods for early diagnosis of prostate cancer and to identify men at risk for developing aggressive disease. Because of the ubiquity of DNA methylation changes and the ability to detect methylated DNA in several body fluids (e.g., blood and urine), this specifically altered DNA may serve, on one hand, as a possible new screening marker for prostate cancer and, on the other hand, as a tool for therapy monitoring in patients having had neoplastic disease of the prostate. Since many prostate cancer patients present with advanced disease and some present with nonspecific elevation of prostate-specific antigen without prostate cancer, early detection with high specificity and sensitivity is considered to be one of the most important approaches to reduce mortality and unwanted tension of the men with high prostate-specific antigen. Therefore, an effective screening test would have substantial clinical benefits. Furthermore, methylation markers of risk of progression of disease in patients having prostate cancer permits immediate commencement of specific treatment regimens and probably longer survival and better quality of life. This review illustrates the current benefits and limitations of potentially useful prostate cancer methylation markers that have considerable existing data and touches upon other future markers as well as the field of methylation in prostate cancer.
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