The role of motility proteins and metastasis-suppressor genes in prostate cancer progression

Decreased expression of SLC 39A14 is associated with tumor aggressiveness and biochemical recurrence of human prostate cancer

Objective

Solute carrier family 39, member 14 (SLC39A14), has been identified as a potential biomarker for various cancers. However, its roles in prostate cancer (PCa) are still unclear. The aim of this study was to investigate the clinical significance of SLC39A14 in patients with PCa and its functions in malignant phenotypes of PCa cells.

Patients and methods

Subcellular localization and expression pattern of SLC39A14 protein were examined by immunohistochemistry. Then, the associations of SLC39A14 expression with various clinicopathological features and clinical outcome of patients with PCa were statistically evaluated. Subsequently, the effects of SLC39A14 overexpression and knockdown on PCa cell proliferation and motility were, respectively, examined by Cell Counting Kit-8, transwell, and wound-healing assays.

Results

The immunoreactive scores of SLC39A14 protein in human PCa tissues were significantly lower than those in normal prostate tissues. Based on the Taylor dataset, SLC39A14 downregulation occurred more frequently in patients with PCa with a higher Gleason score (P<0.001), advanced clinical stage (P=0.008), presence of metastasis (P=0.009), and prostate-specific antigen failure (P=0.006). More interestingly, the survival analysis identified SLC39A14 as an independent factor for predicting the biochemical recurrence-free survival of patients with PCa (P=0.017). Functionally, the enforced expression of SLC39A14 could suppress cell proliferation, invasion, and migration of PCa cell lines in vitro, which could be reversed by the knockdown of SLC39A14.

Conclusion

Decreased expression of SLC39A14 may lead to malignant phenotypes of PCa cells and aggressive tumor progression in patients with PCa. Importantly, SLC39A14 may function as a tumor suppressor and a biomarker for screening patients with biochemical recurrence following radical prostatectomy.

Defining the biologic role of genes that regulate prostate cancer metastasis

Metastasis is the most lethal attribute of a cancer. There is a critical need for markers that will accurately distinguish those histologic lesions and disseminated cells that have a high probability of causing clinically important metastatic disease from those cells that will remain indolent. Despite the explosion in new information regarding the genetics of cancer, only six human genes have thus far been shown to functionally suppress metastasis. The present review and perspective describes the evolving view of the mechanisms that regulate metastasis, and the importance of metastasis-suppressor genes in this process. Specifically, the clinical problem of metastatic prostate cancer, the identification of metastatic colonization as a therapeutic target, and the identification and functional characterization of prostate cancer metastasis-suppressor genes are discussed.

The purinergic calcium channels P2X1,2,5,7 are down-regulated while P2X3,4,6 are up-regulated during apoptosis in the ageing rat prostate

Subtype-specific antibodies were used to measure purinergic (P2X) receptor expression in the rat prostate. In mature Wistar rats, apoptosis and expression of P2X1, P2X2, P2X5 and P2X7 subtypes were all significantly decreased compared with the levels found in immature rat prostates. Accompanying this age-related reduction in purinergic calcium channel expression was a reduction in epithelial and stromal calcium as well as the calcium-regulating hormone stanniocalcin. In contrast, expression of P2X3, P2X4 and P2X6 increased with age. These results suggest that distinct changes in P2X subtype expression accompany apoptosis in the rat prostate.

Utilization of polymerase chain reaction technology in the detection of solid tumors

BACKGROUND

Most cancer detection tests currently performed are based on either antibody assays to a marker protein with altered expression in cancer patients or on imaging studies to identify characteristic lesions. Generally, for a positive result, these detection assays require that a tumor have a significant volume of cancer cells. Advances in diagnostic techniques and technology may allow for cancer detection at earlier stages, when the tumor burden is smaller and potentially more curable. The molecular techniques of polymerase chain reaction (PCR) and reverse transcriptase PCR (RT-PCR) are highly sensitive methods for detecting a small number of cancer cells. Over the past few years, numerous clinical studies have used PCR techniques to detect physical alterations of genes, such as mutations, deletions, translocations and amplification, the presence of oncogenic viruses, and the expression of genes specific to tissue, cancer, and metastasis. The current status of PCR as a method for detecting marker genes in the management of solid tumors is reviewed.

METHODS

A review of the literature on the clinical utility of PCR and RT-PCR in the detection of solid tumor micrometastasis was conducted.

RESULTS

Amplification by PCR is a highly sensitive method to determine gene expression. A single cell expressing a tumor marker among 10-100 million lymphocytes can be detected by the PCR assay. This approach has been used to detect tumor cells in approximately 18 different solid tumor types, with melanoma and carcinoma of the breast and prostate the most widely investigated to date. PCR-based assays have been used to detect cancer cells in biopsies of solid tissue, lymph nodes, bone marrow, peripheral blood, and other body fluids. Several studies have reported a high specificity and sensitivity of tumor marker detection and a high correlation between PCR results and the presence of metastatic disease. However, in a few studies, PCR assays have not consistently demonstrated a higher sensitivity and specificity of detection than traditional modalities for many types of cancer. There has been a wide range in sensitivity and specificity among the studies, which may be partly attributed to the lack of uniformity among the PCR protocols used in different studies.

CONCLUSIONS

PCR can detect tumor marker-expressing cells that are otherwise undetectable by other means in patients with localized or metastatic cancer. Reports from various study groups have lacked uniformity in their protocols, and this has prevented adequate comparison. The clinical utility of this assay as a tool for the prognosis and management of cancer patients remains and area of active investigation. PCR is a powerful tool in the study of the biology of cancer metastasis and will likely serve as a useful adjunct to clinical decision-making in the future.

Utilization of polymerase chain reaction technology in the detection of solid tumors

BACKGROUND

Most cancer detection tests currently performed are based on either antibody assays to a marker protein with altered expression in cancer patients or on imaging studies to identify characteristic lesions. Generally, for a positive result, these detection assays require that a tumor have a significant volume of cancer cells. Advances in diagnostic techniques and technology may allow for cancer detection at earlier stages, when the tumor burden is smaller and potentially more curable. The molecular techniques of polymerase chain reaction (PCR) and reverse transcriptase PCR (RT-PCR) are highly sensitive methods for detecting a small number of cancer cells. Over the past few years, numerous clinical studies have used PCR techniques to detect physical alterations of genes, such as mutations, deletions, translocations and amplification, the presence of oncogenic viruses, and the expression of genes specific to tissue, cancer, and metastasis. The current status of PCR as a method for detecting marker genes in the management of solid tumors is reviewed.

METHODS

A review of the literature on the clinical utility of PCR and RT-PCR in the detection of solid tumor micrometastasis was conducted.

RESULTS

Amplification by PCR is a highly sensitive method to determine gene expression. A single cell expressing a tumor marker among 10-100 million lymphocytes can be detected by the PCR assay. This approach has been used to detect tumor cells in approximately 18 different solid tumor types, with melanoma and carcinoma of the breast and prostate the most widely investigated to date. PCR-based assays have been used to detect cancer cells in biopsies of solid tissue, lymph nodes, bone marrow, peripheral blood, and other body fluids. Several studies have reported a high specificity and sensitivity of tumor marker detection and a high correlation between PCR results and the presence of metastatic disease. However, in a few studies, PCR assays have not consistently demonstrated a higher sensitivity and specificity of detection than traditional modalities for many types of cancer. There has been a wide range in sensitivity and specificity among the studies, which may be partly attributed to the lack of uniformity among the PCR protocols used in different studies.

CONCLUSIONS

PCR can detect tumor marker-expressing cells that are otherwise undetectable by other means in patients with localized or metastatic cancer. Reports from various study groups have lacked uniformity in their protocols, and this has prevented adequate comparison. The clinical utility of this assay as a tool for the prognosis and management of cancer patients remains and area of active investigation. PCR is a powerful tool in the study of the biology of cancer metastasis and will likely serve as a useful adjunct to clinical decision-making in the future.