Prostate transglutaminase (TGase-4) antagonizes the anti-tumour action of MDA-7/IL-24 in prostate cancer

Department of Pathology, University of Arizona College of Medicine, Arizona Cancer Center and BIO5 Institute, Tucson, Arizona, AZ 85724-5043 USA.
Journal of Translational Medicine (Impact Factor: 3.93). 04/2011; 9(1):49. DOI: 10.1186/1479-5876-9-49
Source: PubMed


Transglutamiase-4 (TGase-4), also known as prostate transglutaminase, belongs to the TGase family and is uniquely expressed in the prostate gland. The functions of this interesting protein are not clearly defined. In the present study, we have investigated an unexpected link between TGase-4 and the melanoma differentiation-associated gene-7/interleukin-24 (MDA-7/IL-24), a cytokine known to regulate the growth and apoptosis of certain cancer and immune cells.
Frozen sections of normal and malignant human prostate tissues and human prostate cancer (PCa) cell lines PC-3 and CA-HPV-10, cell lines expressing low and high levels of TGase-4, and recombinant MDA-7/IL-24 (rhMDA-7/IL-24) were used. Expression construct for human TGase-4 was generated using a mammalian expression vector with full length human TGase-4 isolated from normal human prostate tissues. PC-3 cells were transfected with expression construct or control plasmid. Stably transfected cells for control transfection and TGase-4 over expression were created. Similarly, expression of TGase-4 in CA-HPV-10 cells were knocked down by way of ribozyme transgenes. Single and double immunofluorescence microscopy was used for localization and co-localization of TGase-4 and MDA-7/IL-24 in PCa tissues and cells with antibodies to TGase-4; MDA-7/IL-24; IL-20alpha; IL-20beta and IL-22R. Cell-matrix adhesion, attachment and migration were by electric cell substrate impedance sensing and growth by in vitro cell growth assay. A panel of small molecule inhibitors, including Akt, was used to determine signal pathways involving TGase-4 and MDA-7/IL-24.
We initially noted that MDA-7 resulted in inhibition of cell adhesion, growth and migration of human PCa PC-3 cells which did not express TGase-4. However, after the cells over-expressed TGase-4 by way of transfection, the TGase-4 expressing cells lost their adhesion, growth and migratory inhibitory response to MDA-7. On the other hand, CA-HPV-10 cells, a cell type naturally expressing high levels of TGase-4, had a contrasting response to MDA-7 when compared with PC-3 cells. Inhibitor to Akt reversed the inhibitory effect of MDA-7, only in PC-3 control cells, but not the TGase-4 expressing PC-3 cells. In human prostate tissues, TGase-4 was found to have a good degree of co-localization with one of the MDA-7 receptor complexes, IL-20Ra.
The presence of TGase-4 has a biological impact on a prostate cancer cell's response to MDA-7. TGase-4, via mechanism(s) yet to be identified, blocked the action of MDA-7 in prostate cancer cells. This has an important implication when considering the use of MDA-7 as a potential anticancer cytokine in prostate cancer therapies.

  • Source
    • "The finding that TGase-4 is associated with cell-matrix adhesion is not totally surprising. First, previous reports have shown that TGase-4 is connected with the migration and invasiveness of prostate cancer cells [6,7], two cellular functions closely linked to cell-matrix adhesion; second, other members of the TGase family, namely TGase-2 has also been shown to regulate cell-matrix adhesion. Thus, TGase-4 appears to share the function with TGase-2 in regulating matrix adhesion of prostate cancer cells. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Transglutaminase-4 (TGase-4), also known as the Prostate Transglutaminase, is an enzyme found to be expressed predominately in the prostate gland. The protein has been recently reported to influence the migratory and invasiveness of prostate cancer cells. The present study aimed to investigate the influence of TGase-4 on cell-matrix adhesion and search for the candidate active domain[s] within the protein. Human prostate cancer cell lines and prostate tissues were used. Plasmids that encoded different domains and full length of TGase-4 were constructed and used to generate sublines that expressed different domains. The impact of TGase-4 on in vitro cell-matrix adhesion, cell migration, growth and in vivo growth were investigated. Interactions between TGase-4 and focal adhesion complex proteins were investigated using immunoprecipitation, immunofluorescence and phosphospecific antibodies. Results TGase-4 markedly increased cell-matrix adhesion and cellular migration, and resulted in a rapid growth of prostate tumours in vivo. This effect resided in the Core-domain of the TGase-4 protein. TGase-4 was found to co-precipitate and co-localise with focal adhesion kinase (FAK) and paxillin, in cells, human prostate tissues and tumour xenografts. FAK small inhibitor was able to block the action medicated by TGase-4 and TGase-4 core domain. TGase-4 is an important regulator of cell-matrix adhesion of prostate cancer cells. This effect is predominately mediated by its core domain and requires the participation of focal adhesion complex proteins.
    Full-text · Article · Oct 2013 · Journal of Translational Medicine
  • Source
    • "Another interesting finding that also goes toward validating the accuracy of the proteomic method is the differential expression of several prostate specific cancer markers such as the prostatespecific transglutaminase, the prostate associated gene 4 protein, the prostatic acid phosphatase, and the prostate specific membrane antigen (see Figure 2). The presence of the prostate-specific transglutaminase in PCa has been recently reported as a potential antitumour target (Ablin et al., 2011; Jiang & Ablin, 2011). Yet another important finding from this study were proteins reported to be implicated as potential cancer chemoprevention targets also affiliated with poor nutritional status and metabolic syndrome disease (Das et al., 2011; De Nunzio et al., 2011; DeMarzo et al., 2003; Dong, Zhang, Hawthorn, Ganther, & Ip, 2003; Gonzalez-Moreno et al., 2011; Jeronimo et al., 2004; J. Kim et al., 2005; Kuemmerle et al., 2011; Menendez & Lupu, 2007; Nelson et al., 2005; Oh et al., 2006; Sytkowski, Gao, Feldman, & Chen, 2005; Toki et al., 2010; Tsavachidou et al., 2009; Walsh, 2010; C. M. Yang, Yen, Huang, & Hu, 2011; Zeliadt & Ramsey, 2010). "

    Full-text · Chapter · Mar 2012
  • [Show abstract] [Hide abstract]
    ABSTRACT: Prostate transglutaminase-4, also known as TGM4 or transglutaminase P, belongs to the prostate transglutaminase protein family, but is almost uniquely distributed in the prostate gland. Recent years have seen an expansion of interest in this enzyme, which is intriguingly expressed in prostate tissues and prostate cancer. In recent studies, the molecule has been found to have a diverse impact on prostate cancer cell growth, migration and invasiveness, and to be involved in the tumor-endothelial interaction and epithelial-mesenchymal transition, and has a wide interaction with other molecular complexes implicating it as a possible biomarker of aggressive versus nonaggressive cancer, as well as a therapeutic factor. This article reviews the recent progress and discusses the controversies and future directions in this exciting area of prostate cancer research.
    No preview · Article · Jun 2011 · Biomarkers in Medicine
Show more