[Show abstract][Hide abstract] ABSTRACT: Previous studies indicated a role of hepatocellular carcinoma-related protein-1(HCRP-1) in human cancers, however, its expression pattern in renal cell carcinoma (RCC) and the molecular mechanism of HCRP-1 on cancer progression have not been characterized. In the present study, HCRP-1 expression was examined in a RCC tissue microarray. The negative expression of HCRP-1 was significantly correlated with tumor grade (P = 0.002), TNM stage (P = 0.001) and pT status (P = 0.003). Furthermore, we showed a strong correlation between negative HCRP-1 expression and worse overall and disease-specific survival (P = 0.0003 and P = 0.0012, respectively). Knockdown of HCRP-1 promoted cell migration and invasion in 786-O and OS-RC-2 cell lines. HCRP-1 depletion increased matrix metalloproteinase (MMP)-2 protein level, with increased extracellular signal-regulatedkinase (ERK) phosphorylation, which could be reversed by ERK siRNA or ERK inhibitor, PD98059. Further analysis showed that HCRP-1 knockdown induced epidermal growth factor receptor (EGFR) phosphorylation. Treatment with EGFR inhibitor or EGFR siRNA blocked HCRP-1-mediated up-regulation of EGFR, ERK phosphorylation and MMP-2 expression. In summary, our results showed that negative HCRP-1 expression is an independent prognostic factor for RCC patients and promotes migration and invasion by EGFR-ERK-mediated up-regulation of MMP-2. HCRP-1 may serve as a therapeutic target for RCC.
[Show abstract][Hide abstract] ABSTRACT: Sperm-associated antigen 9 (SPAG9) is a recently characterized oncoprotein involved in the progression of several human malignancies. To elucidate the role of SPAG9 in the development of human prostate cancer (PCa), tissue microarray (TMA) and immunohistochemistry were used to detect the clinical relevance of SPAG9 in PCa tissues. We found that SPAG9 expression was increased in the PCa tissues when compared with the level in the tumor adjacent normal prostate tissues, and increased SPAG9 staining was significantly correlated with TNM stage and tumor grade. We also examined prostate cancer cell motility, invasion and angiogenesis ability following reduced SPAG9 expression by siRNA. Our data showed that knockdown of SPAG9 in prostate cancer cell lines inhibited cell motility and invasion due to the inactivation of metalloproteinase-2 (MMP‑2)/MMP-9 by upregulation of tissue inhibitor of metalloproteinase-1 (TIMP-1)/TIMP-2. Furthermore, downregulation of vascular endothelial growth factor (VEGF) secretion greatly contributed to the reduced ability of angiogenesis. Our data indicate that SPAG9 expression is significantly increased in PCa and it may be involved in the process of prostate cancer cell motility, migration and angiogenesis.
[Show abstract][Hide abstract] ABSTRACT: RUNX3 (runt-related transcription factor-3) has been reported to suppress tumor tumorigenesis and metastasis in different human cancers. In this study, we used tissue microarray (TMA) to determine the significance of RUNX3 in prostate cancer progession. Our results showed ectopic expression of RUNX3 in prostate cancer tissues when compared with tumor adjacent normal prostate tissues, and reduced RUNX3 staining was significantly correlated with TNM stage. Moreover, we demonstrated that RUNX3 overexpression inhibited prostate cancer cell migration and invasion resulting from the elevated upregulation of tissue inhibitor of matrix metalloproteinase-2 (TIMP-2), which subsequently inhibited metalloproteinase-2 (MMP-2) expression and activity in vitro. Knock down of RUNX3 expression broke up the balance of TIMP-2/MMP-2, whereas silence of TIMP-2 resulted in the inhibition of MMP-2 expression in prostate cells. We also showed that restoration of RUNX3 decreased vascular endothelial growth factor (VEGF) secretion and suppressed endothelial cell growth and tube formation. Strikingly, RUNX3 was demonstrated to inhibit tumor metastasis and angiogenesis in vivo. Altogether, our results support the tumor suppressive role of RUNX3 in human prostate cancer, and provide insights into development of targeted therapy for this disease.
PLoS ONE 01/2014; 9(1):e86917. DOI:10.1371/journal.pone.0086917 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Purpose:
To evaluate the role of RUNX3 in breast cancer pathogenesis, we examined the RUNX3 expression in breast cancer tissues and analyzed the correlation between RUNX3 expression and clinicopathologic variables and patients survival.
We evaluated the RUNX3 expression by immunohistochemistry using a tissue microarray containing 256 specimens of breast cancer patients. We also studied the role of RUNX3 in cell migration and invasion by performing cell migration and invasion assay. Differential expression of metastasis-related genes after RUNX3 restoration was analyzed using the Human Tumor Metastasis PCR Array.
The RUNX3 expression was significantly correlated with breast cancer histology grade (P = 0.000), and low RUNX3 expression strongly correlated with worse 5-year overall and disease-specific survival rates (P = 0.000 and P = 0.001, respectively). Furthermore, we found that RUNX3 restoration suppressed breast cancer metastasis by controlling cell migration and invasion capacity. Finally, gene expression profiles of RUNX3-549 and Ctrl-549 cells showed matrix metalloproteinase-2 (MMP-2) was the most significant gene among the 84 metastasis-related genes influenced by RUNX3 reintroduction.
Reduced RUNX3 expression is significantly correlated with breast cancer progression and predicts worse survival. RUNX3 regulates breast cancer cell migration and invasion through the MMP-2 pathway.
PLoS ONE 11/2013; 8(3):e59772. DOI:10.1371/journal.pone.0059772 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: RUNX3 (runt-related transcription factor-3) is a known tumor suppressor gene which exhibits potent antitumor activity in several carcinomas. However, little is known about the role of RUNX3 in human renal cell carcinoma (RCC). To investigate the clinical relevance of RUNX3 in RCC patients, immunohistochemistry was performed to detect the clinical relevance of RUNX3 in 75 RCC tissues and paired non-cancerous tissues by using tissue microarray (TMA). We also investigated the role of RUNX3 in RCC cell migration, invasion and angiogenesis. The RUNX3 expression was decreased dramatically in human RCC tissue. The RUNX3 expression was significantly correlated with tumor size (<0.001), depth of invasion (<0.001), and of TNM stage (<0.001). Restoration of RUNX3 significantly decreased renal carcinoma cell migration and invasion capacity compared with controls. In addition, we found that overexpression of RUNX3 reduced the proliferation and tube formation of human umbilical vascular endothelial cells (HUVECs). Gelatin zymography and Western blot showed that RUNX3 expression suppressed matrix metalloproteinase-9 (MMP-9) protein level and enzyme activity. Western blot and ELISA showed that RUNX3 restoration inhibited the expression and secretion of vascular endothelial growth factor (VEGF). Taken together, our studies indicate that decreased expression of RUNX3 in human RCC tissue is significantly correlated with RCC progression. Restoration of RUNX3 expression significantly inhibits RCC cells migration, invasion and angiogenesis. These findings provide new insights into the significance of RUNX3 in migration, invasion and angiogenesis of RCC.
PLoS ONE 02/2013; 8(2):e56241. DOI:10.1371/journal.pone.0056241 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Melanoma differentiation-associated gene-7/interleukin-24 (MDA-7/IL-24) uniquely takes on multiple anticancer functions, such as direct tumor cell cytotoxicity, immune stimulation, and antiangiogenic activities. MDA-7/IL-24 protein levels depend on proteasome degradation. Western blotting and coimmunoprecipitation analyses verified that the MDA-7/IL-24 protein was ubiquitinated and degraded by the 26S proteasome in Hela cells, which was confirmed by protein accumulation treated with proteasome inhibitor MG132. MDA-7/IL-24 contains 10 lysine sites: K63, K69, K78, K119, K123, K136, K179, K189, K203, and K206. Site-directed mutagenesis in these sites reveals that lysine 123 is the major internal lysine involvement of MDA-7/IL-24 ubiquitination. Our results further demonstrated that the mutation of lysine 123 to arginine led to the inhibition of ubiquitin-mediated degradation and the recovery of MDA-7/IL-24 protein level. At the same time, the apoptosis-inducing activity of K123R mutant was obviously stronger than wild-type MDA-7/IL-24 detected by 4'-6-diamidino-2-phenylindole (DAPI) assay and annexin V analysis. In addition, K123R mutant tilted the balance between antiapoptotic protein Bcl-2 and proapoptotic protein Bax, which subsequently induced the cleavage of caspase signaling cascade and initiated cell apoptosis. Together, lysine 123 is mainly implicated in the ubiquitination and degradation of MDA-7/IL-24. Inhibition of degradation and ubiquitination of MDA-7/IL-24 through mutation of lysine 123 result in enhanced stability of MDA-7/IL-24 and exhibits persistent tumor suppression activity compared with the wild type.
Journal of interferon & cytokine research: the official journal of the International Society for Interferon and Cytokine Research 10/2012; 32(12). DOI:10.1089/jir.2012.0055 · 2.00 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Interferon regulatory factor 1 (IRF1) shows tumor-suppressor activity by suppressing proliferation of cancer cells. To exert its anti-proliferative effects, this factor must ultimately control transcription of several key genes that regulate cell cycle progression. Here, we showed that Ki-67 gene is a novel proliferation-related downstream target of IRF1. IRF1 repressed Ki-67 gene transcription in a dose-dependent manner in human Ketr-3 and 786-O renal carcinoma cells. We previously cloned the Ki-67 core promoter which contained two functional Sp1 binding sites. Mutation of the two Sp1 binding sites abrogated Sp1-dependent enhancement of Ki-67 promoter activity. Forced elevation of IRF1 decreased endogenous Sp1 protein level. However, there was no effect on Sp1 mRNA level after transfected with IRF1. Our findings establish a casual series of events that connect anti-proliferative effects of IRF1 with the Ki-67 gene, which encodes a key regulator of the G1/S phase transition. It suggests that the inhibitory effect on Ki-67 gene expression mediated by decreasing level of Sp1 protein might be a novel function of the anti-tumor activity of IRF1.
[Show abstract][Hide abstract] ABSTRACT: Oxidative stress, implicated in the etiology of cancer, results from an imbalance in the production of Reactive Oxygen Species (ROS) and cell's own antioxidant defenses. As a oxidative stress sensor, Keap1 functions as both an adaptor for Cul3⋅Rbx1 E3 ligase complex mediated degradation of the transcription factor Nrf2, and a master regulator of cytoprotective gene expression. Although Nrf2 is a well known substrate for Keap1, the DGR domain of Keap1 has been reported also to bind other proteins directly or indirectly. IKKβ as positive regulator of NF-κB is also destabilized by Keap1, which resulted in inhibiting NF-κB-derived tumor promotion. In addition, anti-apoptotic Bcl-2/Bcl-xL protein was identified as another substrate for the Keap1-Cul3-E3 ligase complex. Keap1 led to the repression and destabilization of Bcl-2, decreased Bcl-2:Bax heterodimers and facilitated cancer cells apoptosis. Given that Keap1 might function as a tumor suppressor protein to mitigate tumor progression, the different kinds of Keap1 somatic mutations were detected in numerous cancer cells. Therefore, it is important to understand the Keap1-involved signaling cascades. This review primarily focuses on the prevention of tumorigenesis role of Keap1 through negative regulation of three substrates Nrf2, IKKβ and Bcl-2/Bcl-xL, with emphasis on the recent findings indicating the cancer guarder function of Keap1.
Cancer letters 06/2012; 325(1):26-34. DOI:10.1016/j.canlet.2012.06.007 · 5.62 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: MDA-7/IL-24 was involved in the specific cancer apoptosis through suppression of Bcl-2 expression, which is a key apoptosis regulatory protein of the mitochondrial death pathway. However, the underlying mechanisms of this regulation are unclear. We report here that tumor-selective replicating adenovirus ZD55-IL-24 leads to Bcl-2 S-denitrosylation and concomitant ubiquitination, which take part in the 26S proteasome degradation. IL-24-siRNA completely blocks Bcl-2 ubiquitination via reversion of Bcl-2 S-denitrosylation and protects it from proteasomal degradation which confirmed the significant role of MDA-7/IL-24 in regulating posttranslational modification of Bcl-2 in cancer cells. Nitric oxide (NO) is a key regulator of protein S-nitrosylation and denitrosylation. The NO donor, sodium nitroprusside (SNP), down-regulates Bcl-2 S-denitrosylation, attenuates Bcl-2 ubiquitination and subsequently counteracts MDA-7/IL-24 induced cancer cell apoptosis, whereas NO inhibitor 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxy-3-oxide (PTIO) shows the opposite effect. At the same time, these NO modulators fail to affect Bcl-2 phosphorylation, suggesting that NO regulates Bcl-2 stability in a phosphorylation-independent manner. In addition, Bcl-2 S-nitrosylation reduction induced by ZD55-IL-24 was attributed to both iNOS decrease and TrxR1 increase. iNOS-siRNA facilitates Bcl-2 S-denitrosylation and ubiquitin-degradation, whereas the TrxR1 inhibitor auranofin prevents Bcl-2 from denitrosylation and ubiquitination, thus restrains the caspase signal pathway activation and subsequent cancer cell apoptosis. Taken together, our studies reveal that MDA-7/IL-24 induces Bcl-2 S-denitrosylation via regulation of iNOS and TrxR1. Moreover, denitrosylation of Bcl-2 results in its ubiquitination and subsequent caspase protease family activation, as a consequence, apoptosis susceptibility. These findings provide a novel insight into MDA-7/IL-24 induced growth inhibition and carcinoma apoptosis.
PLoS ONE 05/2012; 7(5):e37200. DOI:10.1371/journal.pone.0037200 · 3.23 Impact Factor