SR 11302, an AP-1 Inhibitor, Reduces Metastatic Lesion Formation in Ex Vivo 4D Lung Cancer Model.

Activator protein (AP) -1 is a transcription factor, plays important role in cell differentiation, proliferation and apoptosis. Analysis of tumor cells grown on ex vivo 4D lung cancer model shows increase in components of AP-1, c-Fos and c-Jun in circulating tumor cells (CTC) compared to primary tumor. Our aim was to determine whether the AP-1 inhibitor SR11302 reduces metastatic lesion formation in the 4D model. Human lung cancer cell lines A549, H1299, and H460 were grown in the 4D model and treated with SR11302 (1 µM). We compared the number of cells in the metastatic site upon SR11302 treatment and number of viable CTCs isolated from the 4D model with parental cells treated/untreated with SR11302 on a petri dish. There were significantly fewer tumor cells per high-power field on metastatic site in 4D model seeded with H460 (p = 0.009), A549 (p = 0.01), or H1299 (p = 0.02) cells treated with SR11302. Furthermore, the CTCs from SR11302 treated 4D models, seeded with H460 (p = 0.04), A549 (p = 0.008), or H1299 (p = 0.01) cells had significantly fewer viable tumor cells after 4 days in culture than the respective untreated control. However, the SR11302 had no impact on the viability of parental H460 (p = 0.87), A549 (p = 0.93), or H1299 (p = 0.25) cells grown on a petri dish (2D). SR11302 reduces metastatic lesion formation in the ex vivo 4D lung cancer model due to the presence of an independent yet common pathway among three cell lines. The ex vivo 4D model may provide a tool to better understand the complex process of metastasis.

IGF gene polymorphisms and breast cancer in African-American and Hispanic women.

Previous studies from our group and others have shown that increased circulatory levels of the ligand insulin-like growth factor 1 (IGF-1) and decreased levels of the predominant IGF-1 binding protein 3 (IGFBP-3) are associated with an increased incidence of breast cancer and poor outcome. Some studies suggest that, in addition to the influence of environmental factors on the levels of IGF-1 and IGFBP-3, alterations in their gene polymorphisms may play a significant role in the risk of cancer. In this study, we investigated the association between gene polymorphisms along the IGF axis and breast cancer, including the IGF-1 (CA) dinucleotide repeat, IGFBP-3 A-202C single nucleotide polymorphism, and the 2-bp deletion and (AGG)n repeat polymorphisms in the IGF type 1 receptor (IGF-IR). A total of 654 subjects, including both African-American and Hispanic/Latino subjects, were screened for various gene polymorphisms. IGF gene polymorphism genotyping was performed by PCR-GeneScan and PCR-RFLP methods. Our results demonstrated a significant association between the non-19/non-19 IGF-1 (CA)n polymorphism and breast cancer (OR = 1.75; 95% CI = 1.07-2.88; P = 0.027). Furthermore, absence of the wild-type-19 allele and alleles <(CA)19 were strongly associated with breast cancer (OR = 1.82; 95% CI = 1.20-2.77; P = 0.005 and OR = 1.70; 95% CI = 1.19-2.43; P = 0.003, respectively). The association of the non-19/non-19 polymorphism with breast cancer was also more significant in premenopausal women (P = 0.04). We did not find any significant association of the IGFBP-3 polymorphism with breast cancer. In the case of IGF-1R polymorphisms, the only significant trend was in the (AGG)5 allele; however, the frequency of this allele was very rare. In summary, our study demonstrated a significant association of IGF-1 polymorphisms and breast cancer. Future studies are necessary to understand the mechanistic value of these polymorphisms in breast cancer risk.

Global methylation pattern of genes in androgen-sensitive and androgen-independent prostate cancer cells.

Promoter DNA methylation of CpG islands is an important epigenetic mechanism in cancer development. We have characterized the promoter methylation profile of 82 genes in three prostate cancer cell lines (LNCaP, PC3, and DU145) and two normal prostate cell lines (RWPE1 and RWPE2). The methylation pattern was analyzed using a Panomics gene array system that consists of immobilized probes of known gene promoters on a nitrocellulose membrane. Methylation binding protein-purified methylated DNA was hybridized on the membrane and detected by the chemiluminescence method. We analyzed methylation profile in normal (RWPE1) versus cancerous cells and androgen receptor (AR)-sensitive (LNCaP) versus AR-negative cells (DU145 and PC3). Our study shows that >50% of the genes were hypermethylated in prostate cancer cells compared with 13% in normal cell lines. Among these were the tumor suppressor (RB, TMS1, DAPK, RBL1, PAX6, and FHIT), cell cycle (p27KIP1 and CDKN2A), transporters (MDR1, MLC1, and IGRP), and transcription factor (STAT1, CIITA, MYOD, and NPAT) genes. Relative methylation pattern shows that most of these genes were methylated from 5-fold to >10-fold compared with the normal prostate cells. In addition, promoter methylation was detected for the first time in target genes such as RIOK3, STAT5, CASP8, SRBC, GAGE1, and NPAT. A significant difference in methylation pattern was observed between AR-sensitive versus AR-negative cancer cells for the following genes: CASP8, GPC3, CD14, MGMT, IGRP, MDR1, CDKN2A, GATA3, and IFN. In summary, our study identified candidate genes that are methylated in prostate cancer.

Role of caspases in 5-FU and selenium-induced growth inhibition of colorectal cancer cells.

BACKGROUND: The mechanisms that could explain the poor sensitivity to 5-FU in certain colorectal cancer (CRC) cells were investigated and whether or not cotreatment with low doses of selenium would offer a therapeutic benefit was explored. MATERIALS AND METHODS: Four CRC cell lines (Caco2, RKO, DLD1 and HT-29) with defined tumor signatures and seven different chemical forms of selenium were tested. RESULTS: 5-FU partially inhibited the HT-29 and RKO cells, but had a weak effect on the DLD1 and almost none on the Caco2 cells. Selenous acid and sodium selenite induced growth inhibition of the DLD1, RKO and HT-29 cells, with a marginal effect on the Caco2 cells. The Caco2 cells with mutant p53, failure to activate caspase-8, -9, -7 and -3 and with hypermethylated caspase-8 were resistant to 5-FU. Conversely, RKO cells expressing wildtype p53, proteolytically activated caspase-8, -9, -7 and -3 and unmethylated caspase-8 were more responsive to 5-FU and selenous acid-induced apoptosis. CONCLUSION: Combination treatment with selenous acid may offer an efficacious strategy to overcome 5-FU resistance in certain CRC cells.

Association of genetic polymorphism of glutathione S-transferase M1, T1, P1 and susceptibility to bladder cancer.

OBJECTIVE: Glutathione-S-transferases (GSTs) are active in the detoxification of wide variety of endogenous or exogenous carcinogens. We examined the association of the GST gene polymorphism with sporadic bladder cancer patients in Northern India. MATERIAL AND METHODS: The study constituted of 106 bladder cancer cases and 370 age-matched controls. The GSTT1 and GSTM1 null genotypes were identified by multiplex PCR and GSTP1313 A/G by Polymerase Chain Reaction/Restriction Fragment Length Polymorphism method (PCR/RFLP). RESULTS: We observed non-significant association in null alleles of the GSTM1 (p = 0.611, OR = 1.12, 95% CI = 0.72-1.74 and GSTT1 (p = 0.135, OR = 1.45, 95% CI = 0.89-2.37) with risk of bladder cancer. However, the G/G genotype of the GSTP1 gene polymorphism was highly significant when compared to controls (p=0.000, OR = 7.12, 95% CI = 3.14-16.16). The combined analysis of the three risk genotypes demonstrated further increase in the risk of bladder cancer (p = 0.000, OR = 7.29 95% CI = 2.81-18.93). CONCLUSION: Our study demonstrated that GSTP1313 G/G polymorphism is a strong predisposing risk factor for bladder cancer. Combination of three GST genotypes association exhibiting gene-gene interaction further substantiates the increased risk of bladder cancer.

Association of vitamin D receptor gene polymorphism and risk of prostate cancer in India.

INTRODUCTION: Vitamin D plays an important role in the proliferation and differentiation of normal and malignant cells. In several studies polymorphism in the vitamin D receptor (VDR) gene has been reported to be associated with prostate cancer (CaP). The rationale of this study was to determine the association between the VDR (Fok-I) polymorphism and the risk of developing CaP. MATERIALS AND METHODS: Polymorphism was detected by the polymerase chain reaction (PCR)-restriction fragment length polymorphism method in 128 CaP patients (age range 43-89 years) and 147 age-matched controls (age range 42-91 years). PCR products were designated as F or f allele according to the absence or presence of a restriction site. RESULTS AND CONCLUSIONS: The frequencies of the FF, Ff and ff genotypes were 60.9, 35.2 and 3.9% in CaP patients and 42.2, 46.9 and 10.9% in healthy controls, respectively. The genotype frequency distribution between CaP and the control group was statistically significant (p = 0.003). However, the distribution of genotypes was not significantly associated with the Gleason score. The present study thus demonstrates that the FF genotype (or F allele) of the VDR gene plays an important role in determining the risk of CaP and could be postulated as a good candidate genetic marker.