Beihai Jiang

PRL-3 promotes the motility, invasion, and metastasis of LoVo colon cancer cells through PRL-3-integrin β1-ERK1/2 and-MMP2 signaling

BackgroundPhosphatase of regenerating liver-3 (PRL-3) plays a causative role in tumor metastasis, but the underlying mechanisms are not well understood. In our previous study, we observed that PRL-3 could decrease tyrosine phosphorylation of integrin β1 and enhance activation of ERK1/2 in HEK293 cells. Herein we aim to explore the association of PRL-3 with integrin β1 signaling and its functional implications in motility, invasion, and metastasis of colon cancer cell LoVo.MethodsTranswell chamber assay and nude mouse model were used to study motility and invasion, and metastsis of LoVo colon cancer cells, respectively. Knockdown of integrin β1 by siRNA or lentivirus were detected with Western blot and RT-PCR. The effect of PRL-3 on integrin β1, ERK1/2, and MMPs that mediate motility, invasion, and metastasis were measured by Western blot, immunofluorencence, co-immunoprecipitation and zymographic assays.ResultsWe demonstrated that PRL-3 associated with integrin β1 and its expression was positively correlated with ERK1/2 phosphorylation in colon cancer tissues. Depletion of integrin β1 with siRNA, not only abrogated the activation of ERK1/2 stimulated by PRL-3, but also abolished PRL-3-induced motility and invasion of LoVo cells in vitro. Similarly, inhibition of ERK1/2 phosphorylation with U0126 or MMP activity with GM6001 also impaired PRL-3-induced invasion. In addition, PRL-3 promoted gelatinolytic activity of MMP2, and this stimulation correlated with decreased TIMP2 expression. Moreover, PRL-3-stimulated lung metastasis of LoVo cells in a nude mouse model was inhibited when integrin β1 expression was interfered with shRNA.ConclusionOur results suggest that PRL-3s roles in motility, invasion, and metastasis in colon cancer are critically controlled by the integrin β1-ERK1/2-MMP2 signaling.

p37 from Mycoplasma hyorhinis promotes cancer cell invasiveness and metastasis through activation of MMP-2 and followed by phosphorylation of EGFR

High Mycoplasma infection in gastric cancer tissues suggests a possible association between Mycoplasma infection and tumorigenesis. By using human gastric cancer cells AGS and mouse melanoma cells B16F10 stably expressing p37, the major immunogen of Mycoplasma hyorhinis, we found that p37 enhanced cell motility, migration, and invasion in vitro. With experimental metastasis model in C57BL/6 mice, p37 adenovirus-infected B16F10 cells formed more metastasis lesions in the lung. Furthermore, p37 promoted the phosphorylation of epidermal growth factor receptor (EGFR) and extracellular signal-regulated kinase and the activity of matrix metalloproteinase-2 (MMP-2). Inhibitor of MMPs significantly blocked p37-induced EGFR but has little effect on extracellular signal-regulated kinase phosphorylation, whereas the p37-induced MMP-2 activation was only partially suppressed by inhibitor of MEK1/2 or by inhibitor of EGFR. However, all these inhibitors significantly reduced the p37-induced invasiveness of AGS cells. These results suggest that p37 may stimulate invasion by increasing the activity of MMP-2, thereby inducing EGFR phosphorylation and contributing to tumor metastasis on M. hyorhinis infection. p37 and its regulated molecules could be the potential targets for cancer therapy. [Mol Cancer Ther 2008;7(3):530–7]

Neuronal protein synuclein γ predicts poor clinical outcome in breast cancer

Synuclein γ (SNCG), previously identified as a breast cancer‐specific gene (BCSG1), is highly expressed in breast carcinomas but not in normal epithelium. SNCG regulates many pathways in growth and progression of breast cancer. To determine if SNCG is a biomarker for clinical prognosis of breast cancer, we generated a panel of murine monoclonal antibodies (mAbs) against human SNCG and correlated SNCG protein expression in 358 clinical breast cancer specimens with clinical outcome. A panel of 14 mAbs was characterized by ELISA, immunoprecipitation (IP), Western blot, immunocytochemistry and immunohistochemistry. SNCG protein expression was determined in 438 clinical breast specimens by immunohistochemical analysis using mAb 5C5. Expression of SNCG was strongly correlated with the stage, lymph node involvement, metastasis, tumor size and Her‐2 status, but its expression was not associated with ER and PR expression status. While 71.4% of advanced breast cancers were positive for SNCG expression, only 26.8% of Stage I/II breast cancers were positive for SNCG expression and 5.2% of benign hyperplasia expressed SNCG. SNCG protein was not detectable in normal tissue adjacent to breast cancer. After a median follow‐up of 64 months, patients with an SNCG‐positive tumor had a significantly shorter disease‐free survival and overall survival and a high probability of death compared no expression of SNCG. Multivariate analysis demonstrated that SNCG was a strong independent prognostic variable. SNCG is a new unfavorable prognostic marker for breast cancer progression and a potential target for breast cancer treatment.

Generation of novel monoclonal antibodies and their application for detecting ARD1 expression in colorectal cancer

Arrest defective 1 (ARD1) is an acetyltransferase involved in cell cycle control in yeast. ARD1 interacts with human N-acetyltransferase (NATH) to form a functional N-terminal acetyltransferase complex. Recently it had been linked with proliferation and apoptosis in mammalian cells, but its function in cancer development remains unclear. To evaluate significance of ARD1 expression in human colorectal cancer, we generated a panel of monoclonal antibodies (mAbs) with high specificity and sensitivity against ARD1. All of the 10 different clones could be used in ELISA and Western blot, and clone 10C12, 13G2, and 4D10 can interact with ARD1 in eukaryotic cells by immunoprecipitation (IP). Clones of 14D4 and 10C12 were strongly reacted to ARD1 in immunocytochemistry (ICH) and immunohistochemistry (IHC). ARD1 expression was evaluated in human colorectal cancer and colitis tissues by immunohistochemical analysis with mAb 14D4. Forty-one were ARD1-positive in 50 colorectal cancer tissues and only 12 were weak positive in the 50 matched normal tissues (P < 0.001). Moreover, ARD1 expression was not detectable in 20 cases of colitis tissue (P < 0.001). Furthermore, all of the six human colorectal cancer cell lines we examined were also ARD1-positive at mRNA and protein levels. Taken together, the novel mAbs against ARD1 we generated could be good tools for both basic and clinical studies, and ARD1 could be a potential biomarker in colorectal cancer.

Prognostic significance of phosphatase of regenerating liver-3 expression in ovarian cancer.

Phosphatase of regenerating liver-3 (PRL-3) is overexpressed in several human cancers and associated with tumor progression, invasion and metastasis. However, the correlation between PRL-3 expression and clinical outcome in ovarian cancer has not been studied. In the present study, we investigated the expression of PRL-3 in 119 ovarian cancers and 30 normal ovarian tissues by immunohistochemistry with an anti-PRL-3 mouse monoclonal antibody 3B6, and analyzed its relationship with clinicopathologic factors and survival. The results demonstrated that PRL-3 expression was significantly higher in ovarian cancers compared to normal ovarian tissues (P < 0.001). PRL-3 expression is not correlated with patient age, menstruation, tumor size, histological type, residual tumor, or other clinical findings. The patients with PRL-3-positive tumors had a significant poor prognosis than those with PRL-3-negative tumors. Univariate analysis identified PRL-3 expression as a poor outcome predictor (HR 1.925, 95% CI, 1.046–3.544, P = 0.035). Multivariate analysis indicated that PRL-3 expression was an independent prognostic factor of borderline significance (HR 1.695, 95% CI, 0.914–3.145, P = 0.094). Our results suggest that PRL-3 may serve as a valuable marker for diagnosis of ovarian cancer and as a potential independent prognostic factor for ovarian cancer.

Combined Phenotype of 4 Markers Improves Prognostic Value of Patients With Colon Cancer

Introduction:Combination of multiple biomarkers representing distinct aspects of tumor biology will have a better prognostic value. This study was to identify prognostic subgroups of colon adenocarcinoma by combined analysis of synuclein-gamma (SNCG), a human homologue of piwi (Hiwi), phosphatase of regenerating liver-3 (PRL-3), arrest-defective protein 1, homolog A (ARD1) and clinicopathologic features in 225 colon adenocarcinoma specimens. Methods:Immunohistochemistry for 4 tumor markers was performed in whole tissue sections from 225 colon adenocarcinoma patients with complete clinicopathologic data and up to 10-year follow-up. The immunohistochemical expression patterns were examined individually and in multimarker combinations. Univariate and multivariate analyses were performed to identify independent predictive markers of poor outcome. Results:With the tumor marker positive rate [32.0% (62/225) for SNCG; 76.9% (173/225) for combined SNCG/Hiwi/PRL-3/ARD1] and the detecting accuracy [61.9% (252/407) for SNCG; 82.6% (336/407) for combined SNCG/Hiwi/PRL-3/ARD1] increasing, incremental value of combined SNCG/Hiwi/PRL-3/ARD1 (P < 0.001; hazard ratios (HR), 3.2) to poor outcome was found. Stratified by lymph node, Hiwi alone (P = 0.004; HR, 3.2) led to poor outcome in patients without lymph node metastasis (LN−), and SNCG (P < 0.001; HR, 2.5) had independently poor prognostic value for patients with lymph node metastasis (LN+). Conclusions:Multimarker phenotypes improved tumor positive rate, detecting accuracy and prognostic value. In addition, a subgroup of more aggressive tumors can be identified by evaluating Hiwi level in LN− cancer, and SNCG level in LN+ cancer.

N-α-Acetyltransferase 10 protein inhibits apoptosis through RelA/p65-regulated MCL1 expression

N-α-Acetyltransferase 10 protein (Naa10p/ARD1), the catalytic subunit of N-acetyltransferase A, catalyzes both N-α-acetylation and ε-acetylation, as well as autoacetylation. Naa10p is involved in controlling cell proliferation, apoptosis, autophagy and neuronal development. Our group and others had reported prognostic value of Naa10p expression in various types of cancer. Despite the efforts to elucidate the biological function of Naa10p, it remains controversial regarding its roles in tumor development. Herein, we report that depletion of Naa10p inhibited the growth of xenograft tumors in nude mice. Microarray analysis identified MCL1 gene as one of targets downstream of Naa10p. Naa10p positively regulated MCL1 expression, as exogenous Naa10p promoted MCL1 expression, whereas Naa10p silencing decreased MCL1 expression. Ablation of Naa10p sensitized cancer cells to stimuli-induced apoptosis, and the anti-apoptotic function of Naa10p was, at least in part, mediated by MCL1. Mechanistically, we found a physical interaction between Naa10p and RelA/p65. Transcriptional activation of the MCL1 gene required the recruitment of Naa10p-RelA/p65 complex to the p65-binding site of MCL1 promoter region. We also demonstrated a positive correlation between MCL1 and Naa10p messenger RNA levels in both colon cancer and lung cancer tissues. These results indicate that Naa10p inhibits apoptosis through Naa10p-RelA/p65-dependent MCL1 transcriptional activation.

Peptide mimic isolated by autoantibody reveals human arrest defective 1 overexpression is associated with poor prognosis for colon cancer patients.

Tumor-associated antigens, which induce the generation of autoantibodies, are useful as cancer biomarkers in early detection and prognostic prediction of cancer. To isolate a novel cancer marker, we used serum antibodies from colon cancer patients to screen a phage display peptide library. A positive peptide 249C (VPLYSNTLRYGF) that could specifically react with serum from colon cancer patients was isolated, and the corresponding antigen-human arrest defective 1 (ARD1A), which shares an identical LYSNTL motif with 249C, was identified. Both immunological assays and three-dimensional structure analysis showed that the LYSNTL region is an epitope of ARD1A. Using ELISA and immunohistochemistry, we found anti-ARD1A antibody levels in serum from patients with colon cancer were significantly higher than those in healthy volunteers (P < 0.001), and ARD1A expression was detected in 84.1% (227/270) of colon cancer tissues compared with 22.7% (55/242) of matched noncancerous tissues (P < 0.001) and 4.8% (2/42) of benign lesions (P < 0.001). Furthermore, multivariate analysis with Cox proportional hazards regression models revealed that ARD1A-positive patients had significantly shortened overall survival (OS) (HR, 1.91, P = 0.039) and borderline significantly shortened disease-free survival (DFS) (HR, 1.70; P = 0.068). Kaplan-Meier survival curves also showed that ARD1A expression was associated significantly with shortened DFS (P = 0.037) and OS (P = 0.019). These results indicate that ARD1A is a novel tumor-associated antigen and a potential prognostic factor for colon cancer.

Inhibition of STAT5a by Naa10p contributes to decreased breast cancer metastasis

N-α-Acetyltransferase 10 protein (Naa10p, also called arrest-defective 1), the catalytic subunit of N-acetyltransferase A, is a critical regulator of cell death and proliferation. Naa10p is also shown to regulate cancer metastasis by inhibiting cell motility; however, its role in cancer metastasis is not fully understood. In this study, we found that high expression of Naa10p is positively correlated with the survival of patients with breast cancer, whereas negatively correlated with lymph node metastasis. Naa10p inhibits breast cancer cell migration and invasion in vitro and decreases the xenograft growth and metastasis in nude mice. Microarray screening revealed that Naa10p downregulates inhibitors of differentiation 1 (ID1) expression. Naa10p binds to signal transducer and activator of transcription 5a (STAT5a) and decreases STAT5a-stimulated ID1 expression in an acetyltransferase-independent manner. Moreover, Naa10p antagonizes Janus kinase 2-STAT5a signaling by lowering p65-activated interleukin-1β expression. Our results demonstrate a novel mechanism through which Naa10p inhibits the metastasis of breast cancer cells by targeting STAT5a.

N-α-acetyltransferase 10 protein is a negative regulator of 28S proteasome through interaction with PA28β.

Naa10p physically interacts with PA28 alpha and PA28 beta by anti bait coimmunoprecipitation (View Interaction: 1, 2)