26471

NUPR1

COM1|P8;nuclear protein, transcriptional regulator, 1;NUPR1;nuclear protein, transcriptional regulator, 1

candidate of metastasis 1|nuclear protein 1|protein p8

16p11.2

protein-coding

Com-1, candidate of metastasis-1, also known as p8, is a recently discovered molecule with a putative role in determining the metastatic nature of cancer cells. We have investigated the expression of Com-1 in normal and malignant human prostate tissues and its molecular interaction within prostate cancer cells. The expression of Com-1 in human prostate tissues and prostate cancer cell lines was assessed at both the mRNA and protein levels, by RT-PCR and immunohistochemistry. The staining intensity of Com-1 was semiquantified using computer assisted image analysis. Full- length Com-1 cDNA was isolated from normal mammary tissues. Ribozyme transgenes that specifically target human Com-1 were constructed using the pEF6/V5-His vector. The growth of prostate cancer cells in vitro and tumour growth in vivo (athymic mice model) following Com-1 overexpression in prostate cancer cells were determined. In normal prostate tissues, the epithelial cells strongly stained Com-1, both in the cytoplasm and in the nucleus. In contrast, prostate cancer cells in tumour tissue showed substantially reduced Com-1 staining levels (p < 0.05 compared to normal cells for both cytoplasmic and nucleus staining), whereas the prostate cancer cell lines PC-3, DU145 and CA-HPV10 widely expressed Com-1. Transfection of these cells with hammerhead ribozyme transgenes resulted in the loss of expression of the Com-1 transcript. Using an in vitro invasion assay we found that the loss of Com-1 from prostate cancer cells increased their invasiveness. Knockout of Com-1 also resulted in the accelerated growth of all three cell lines. Forced overexpression of Com-1/ p8 in prostate cancer cells was able to reverse the changes in invasiveness and growth seen with the Com-1 knock-out cells. In a spontaneous tumour model, it was demonstrated that PC-3 cells with forced overexpression of Com-1 (PC-3com1Exp) had a significantly slower rate of growth compared with control cells (tumour size 36.6 +/- 31.2 vs 114.3 +/- 68.1 mm3, for tumours from PC-3com1Exp and control PC-3 cells, respectively, p = 0.0023). In conclusion, Com-1/p8 was expressed at lower levels in human prostate cancer cells compared with normal epithelial cells. Com-1/p8 levels are inversely correlated with the invasiveness and growth of prostate cancer cells in vitro and the overexpression of Com-1 reduced the growth of prostate tumours in vivo. Com-1/p8 is a potential tumour suppressor in human prostate cancer.

The incidence of pancreatic adenocarcinoma is increasing with more than 43,000 predicted new cases in the US and 65,000 in Europe this year. Pancreatic cancer patients have a short life expectancy with less than 3-4% 5-y survival, which results in an equivalent incidence and mortality rate. One of the major challenges in pancreatic cancer is the identification of pharmacological approaches that overcome the resistance of this cancer to therapy. Intensive research in the past decades has led to the classification of pancreatic cancers and the identification of the driver key genetic events. Despite the advances in understanding the molecular mechanisms responsible for pancreatic cancer pathogenesis, this knowledge had little impact on significantly improving the treatment for this dismal disease. In particular, we know today that the lack of therapeutic response in pancreatic cancer is due to the intrinsic high resistance of these tumors to chemotherapy and radiation, rather than to the inappropriate design of these therapeutic approaches. Thus, in order to ensure a better outcome for pancreatic cancer patients, there is a strong need for research focused on the mechanism that determines this resistant phenotype and the means that might drive enhanced response to therapy.