INTRODUCTION: Prostate-specific membrane antigen (PSMA) was originally found to be specifically expressed in normal prostate, and its expression was upregulated in almost all stages of prostate cancer. In recent years, PSMA was also found to be expressed in tumor-associated vasculature in many nonprostatic solid tumors. However, the expression pattern of PSMA in hepatocellular carcinoma (HCC) is not well studied. METHODS: In this study, we examined PSMA expression in 103 HCC tissues using immunohistochemical staining and analyzed the association between PSMA expression and other clinicopathological features and prognosis. RESULTS: Among the 103 cases, 27 cases (26%) showed PSMA expression in more than 50% of tumor-associated vasculature, 49 cases (48%) showed PSMA expression in less than 50% of vasculature, and 27 cases (26%) did not have detectable PSMA expression. Vascular PSMA expression was associated with several clinicopathological features, such as tumor stage, tumor differentiation, lymph node metastasis, and Ki-67 index. Furthermore, high vascular PSMA expression was also associated with poor prognosis in patients with HCC. Univariate and multivariate analyses showed that high vascular PSMA expression can be used as an independent prognostic marker for HCC. DISCUSSION: Our study provides the evidence that PSMA is specifically expressed in tumor-associated vasculature of HCC, and vascular PSMA expression may be used as a novel prognostic marker and a vascular therapeutic target for HCC.

◥Fibroblasts and macrophages play key roles in the development of hepatocellular carcinoma (HCC). However, cross-talk between these two kinds of cells has not been well studied. Endosialin (CD248/TEM1) is a transmembrane glycoprotein that is expressed in certain cancer cells, tumor stromal cells, and pericytes. In this study, we found that endosialin is mainly expressed in cancer-associated fibroblasts (CAF) in HCC and its expression inversely correlates with patient prognosis. Endosialin interacted with CD68 to recruit macrophages and regulated expression of GAS6 in CAFs to mediate M2 polarization of macrophages. The fully human antibody IgG78 bound glycosylated endosialin and induced its internalization in CAFs, thus weakening the cross-talk between CAFs and macrophages. In subcutaneous and orthotopic xenograft models of HCC in nude mice, treatment with IgG78 significantly inhibited tumor growth. These results indicate that endosialin-positive CAFs promote HCC progression and highlight IgG78 as a promising therapeutic candidate for HCC treatment.

High mobility group box 1 (HMGB1), a critical damage-associated molecular pattern molecule, has been implicated in several inflammatory diseases and cancer types. The overexpression of HMGB1 protein occurs in prostate cancer, and is closely associated with the proliferation and aggressiveness of tumor cells. However, the underlying mechanisms of HMGB1-induced tumor metastasis in prostate cancer remain unclear. In the present study, it was demonstrated that the expression of HMGB1 was high in prostate cancer samples, particularly in the metastatic tissues. Furthermore, recombinant HMGB1 (rHMGB1) enhanced the invasive and metastatic capabilities of the prostate cancer cells. Molecular phenotype alterations of epithelial-to-mesenchymal transition (EMT) and elevated expression levels of matrix metalloproteinase (MMP)-1, -3 and -10 were observed. In addition, advanced glycosylation end-product specific receptor (RAGE) and its downstream molecule nuclear factor (NF)-κB pathway were activated during rHMGB1-induced metastasis. Silencing RAGE or NF-κB reversed the upregulation of MMP and EMT marker expression levels, thus reducing the migration and invasiveness of tumor cells. Taken together, these results suggest that highly expressed HMGB1 drives EMT and the overexpression of MMP-1, -3, -10 via the RAGE/NF-κB signaling pathways, which facilitates the metastasis of prostate cancer and may be a potential therapeutic target for metastatic prostate cancer.

The study was aimed at assessing the diagnostic performance of 68 Ga-PSMA-617 PET/CT in the detection of prostate cancer (PCa) in patients with a prostate-specific antigen (PSA) level of 4-20 ng/ ml and to compare its efficacy with that of multiparametric MRI (mpMRI). We analyzed the data of 67 consecutive patients with PSA levels of 4-20 ng/ml who almost simultaneously underwent 68 Ga-PSMA-617 PET/CT and mpMRI. 68 Ga-PSMA-617 PET/CT and mpMRI diagnostic performances were compared via receiver operating characteristic (ROC) curve analysis. Of the 67 suspected PCa cases, 33 had pathologically confirmed PCa. 68 Ga-PSMA-617 PET/CT showed a patient-based sensitivity, specificity, and positive and negative predictive values (PPVs and NPVs) of 87.88%, 88.24%, 87.88%, and 88.24%, respectively. The corresponding values for mpMRI were 84.85%, 52.94%, 63.64%, and 78.26%. The area under the curve values for 68 Ga-PSMA-617 PET/CT and mpMRI were 0.881 and 0.689, respectively. 68 Ga-PSMA-617 PET/CT showed a better diagnostic performance than mpMRI in the detection of PCa in patients with PSA levels of 4-20 ng/ml.

RNF2, also known as RING1b or RING2, is identified as the catalytic subunit of polycomb repressive complex 1 (PRC1), which mediates the mono-ubiquitination of histone H2A. RNF2 has been proved to have oncogenic function in many kinds of cancers, but the function of RNF2 in prostate cancer (PCa) has not been evaluated. Here we show that PCa tissues showed higher RNF2 expression than the benign prostatic hyperplasia (BPH) tissues. Knockdown of RNF2 in PCa cells resulted in cell cycle arrest, increased apoptosis and inhibited cell proliferation, and the growth of RNF2 knockdown PCa xenografts were obviously inhibited in nude mice. Gene microarray analysis was performed and tumor suppressor gene TXNIP was found to be significantly increased in RNF2 knockdown cells. Simultaneously knockdown of RNF2 and TXNIP can partially rescue the arrested cell cycle, increased apoptosis and inhibited cell proliferation in RNF2 single knockdown cells. Furthermore, ChIP assay result showed that RNF2 enriched at the TXNIP promoter, and the enrichment of RNF2 and ubiquitination of H2A in TXNIP promoter was obviously inhibited in RNF2 knockdown cells. In conclusion, our results demonstrate that RNF2 functions as an oncogene in PCa and RNF2 may regulate the progression of PCa through the inhibition of TXNIP.