Wenzhi Shen

ATF4 is directly recruited by TLR4 signaling and positively regulates TLR4-trigged cytokine production in human monocytes.

Toll-like receptors (TLRs) are sentinels of the host defense system, which recognize a large number of microbial pathogens. The host defense system may be inefficient or inflammatory diseases may develop if microbial recognition by TLRs and subsequent TLR-triggered cytokine production are deregulated. Activating transcription factor 4 (ATF4), a member of the ATF/CREB transcription factor family, is an important factor that participates in several pathophysiological processes. In this report, we found that ATF4 is also involved in the TLR-mediated innate immune response, which participates in TLR4 signal transduction and mediates the secretion of a variety of cytokines. We observed that ATF4 is activated and translocates to the nucleus following lipopolysaccharide (LPS) stimulation via the TLR4-MyD88-dependent pathway. Additionally, a cytokine array assay showed that some key inflammatory cytokines, such as IL-6, IL-8 and RANTES, are positively regulated by ATF4. We also demonstrate that c-Jun directly binds to ATF4, thereby promoting the secretion of inflammatory cytokines. Taken together, these results indicate that ATF4 acts as a positive regulator in TLR4-triggered cytokine production.

TIFA suppresses hepatocellular carcinoma progression via MALT1-dependent and -independent signaling pathways

TIFA, also called T2BP, was first identified using yeast two-hybrid screening. Our previous work showed that TIFA suppresses hepatocellular carcinoma (HCC) progression via apoptosis and cell cycle arrest. However, the mechanism by which this TIFA suppression occurs remains unclear. Here we demonstrated that TIFA-induced apoptosis demonstrates two distinct time patterns (i.e., at 48 h and >7 days) when TIFA reconstitution occurs. Moreover, we found that MALT1 (a competitor of TIFA) plays a crucial role in short-duration TIFA reconstitution. In this regard, MALT1 silencing with shRNA markedly enhances TIFA-induced apoptosis in vitro and in vivo. In addition, TIFA overexpression triggers JNK and p38 activation in long-duration TIFA reconstitution through TRAF6 binding. In particular, JNK activation leads to TIFA-induced apoptosis while p38 activation governs TIFA-induced cell cycle arrest by p53-p21 signaling in vitro and in vivo. Our data suggest a novel mechanism by which TIFA suppresses HCC progression via both MALT1-dependent and MALT1-independent signaling pathways. This may provide insights into a novel targets where HCC progression may be vulnerable to clinical treatment.

TIFA, an inflammatory signaling adaptor, is tumor suppressive for liver cancer

TIFA (TNF receptor associated factor (TRAF)-interacting protein with a Forkhead-associated (FHA) domain), also called T2BP, was first identified using a yeast two-hybrid screening. TIFA contains a FHA domain, which directly binds phosphothreonine and phosphoserine, and a consensus TRAF6-binding motif. TIFA-mediated oligomerization and poly-ubiquitinylation of TRAF6 mediates signaling downstream of the Tumor necrosis factor alpha receptor 1 (TNFaR-I) and interleukin-1/Toll-like receptor 4 (TLR4) pathways. Examining TIFA expression in hepatocellular carcinoma (HCC) tissues microarrays, we noted marked decreases TIFA reactivity in tumor versus control samples. In agreement, we found that HCC cell lines show reduced TIFA expression levels versus normal liver controls. Reconstituting TIFA expression in HCC cell lines promoted two independent apoptosis signaling pathways: the induction of p53 and cell cycle arrest, and the activation of caspase-8 and caspase-3. In contrast, the expression of a non-oligomerizing mutant of TIFA impacted cells minimally, and suppression of TIFA expression protected cells from apoptosis. Mice bearing TIFA overexpression hepatocellular xenografts develop smaller tumors versus TIFA mutant tumors; terminal deoxynucleotidyl transferase dUTP nick end labeling staining demonstrates increased cell apoptosis, and decreased proliferation, reflecting cell cycle arrest. Interestingly, p53 has a greater role in decreased proliferation than cell death, as it appeared dispensable for TIFA-induced cell killing. The findings demonstrate a novel suppressive role of TIFA in HCC progression via promotion of cell death independent of p53.

Machine learning-based classification of diffuse large B-cell lymphoma patients by eight gene expression profiles.

Gene expression profiling (GEP) had divided the diffuse large B‐cell lymphoma (DLBCL) into molecular subgroups: germinal center B‐cell like (GCB), activated B‐cell like (ABC), and unclassified (UC) subtype. However, this classification with prognostic significance was not applied into clinical practice since there were more than 1000 genes to detect and interpreting was difficult. To classify cancer samples validly, eight significant genes (MYBL1, LMO2, BCL6, MME, IRF4, NFKBIZ, PDE4B, and SLA) were selected in 414 patients treated with CHOP/R‐CHOP chemotherapy from Gene Expression Omnibus (GEO) data sets. Cutoffs for each gene were obtained using receiver–operating characteristic curves (ROC) new model based on the support vector machine (SVM) estimated the probability of membership into one of two subgroups: GCB and Non‐GCB (ABC and UC). Furtherly, multivariate analysis validated the model in another two cohorts including 855 cases in all. As a result, patients in the training and validated cohorts were stratified into two subgroups with 94.0%, 91.0%, and 94.4% concordance with GEP, respectively. Patients with Non‐GCB subtype had significantly poorer outcomes than that with GCB subtype, which agreed with the prognostic power of GEP classification. Moreover, the similar prognosis received in the low (0–2) and high (3–5) IPI scores group demonstrated that the new model was independent of IPI as well as GEP method. In conclusion, our new model could stratify DLBCL patients with CHOP/R‐CHOP regimen matching GEP subtypes effectively.

miR-885-5p suppresses hepatocellular carcinoma metastasis and inhibits Wnt/β-catenin signaling pathway

MicroRNAs (miRNAs) inhibit or improve the malignant progression of hepatocellular carcinoma (HCC). We previously reported that compared to health controls, patients with liver cirrhosis present the highest levels of circulating miR-885-5p, followed by those with chronic hepatitis B and those with HCC. However, the molecular involvement of miR-885-5p in HCC metastasis is presently unclear. Here, we demonstrated that the expression of miR-885-5p negatively correlated with the invasive and metastatic capabilities of human HCC tissue samples and cell lines. We found that miR-885-5p expression levels correlated with the survival of patients with HCC. Overexpression of miR-885-5p decreased metastasis of HCC cells in vitro and in vivo. Inhibition of miR-885-5p improved proliferation of non-metastatic HCC cells. Furthermore, we disclosed that miR-885-5p targeted gene encoding β-catenin CTNNB1, leading to decreased activity of the Wnt/β-catenin signaling pathway. The present study indicates that miR-885-5p suppresses the metastasis of HCC and inhibits Wnt/β-catenin signaling pathway by its CTNNB1 target, which suggests that miR-885-5p to be a promising negative regulator of HCC progression and as a novel therapeutic agent to treat HCC.

Liposomal Nanoparticles Carrying anti-IL6R Antibody to the Tumour Microenvironment Inhibit Metastasis in Two Molecular Subtypes of Breast Cancer Mouse Models

Tumour microenvironment (TME) contributes significantly towards potentiating the stemness and metastasis properties of cancer cells. IL6-Stat3 is one of the important cell signaling pathways in mediating the communication between tumour and immune cells. Here, we have systematically developed a novel anti-CD44 antibody-mediated liposomal nanoparticle delivery system loaded with anti-IL6R antibody, which could specifically target the TME of CD44+ breast cancer cells in different mouse models for triple negative and luminal breast cancer. This nanoparticle had an enhanced and specific tumour targeting efficacy with dramatic anti-tumour metastasis effects in syngeneic BALB/c mice bearing 4T1 cells as was in the syngeneic MMTV-PyMT mice. It inhibited IL6R-Stat3 signaling and moderated the TME, characterized by the reduced expression of genes encoding Stat3, Sox2, VEGFA, MMP-9 and CD206 in the breast tissues. Furthermore, this nanoparticle reduced the subgroups of Sox2+ and CD206+ cells in the lung metastatic foci, demonstrating its inhibitory effect on the lung metastatic niche for breast cancer stem cells. Taken together, the CD44 targeted liposomal nanoparticles encapsulating anti-IL6R antibody achieved a significant effect to inhibit the metastasis of breast cancer in different molecular subtypes of breast cancer mouse models. Our results shed light on the application of nanoparticle mediated cancer immune-therapy through targeting TME.

The long non-coding RNA NONHSAG026900 predicts prognosis as a favorable biomarker in patients with diffuse large B-cell lymphoma

Long non-coding RNAs are known to be involved in cancer progression, but their biological functions and prognostic values are still largely unexplored in diffuse large B-cell lymphoma. In this study, long non-coding RNAs expression was characterized in 1,403 samples including normal and diffuse large B-cell lymphoma by repurposing 7 microarray datasets. Compared with any stage of normal B cells, NONHSAG026900 expression was significantly decreased in tumor samples. And in germinal center B-cell subtype, the significantly higher expression of NONHSAG026900 indicated it was a favorable prognosis biomarker. Then the prognostic power of NONHSAG026900 was validated with another independent dataset and NONHSAG026900 improved the predictive power of International Prognostic Index as an independent factor. Moreover, functional prediction and validation demonstrated that NONHSAG026900 could inhibit cell cycle activity to restrain tumor proliferation. These findings identified NONHSAG026900 as a novel prognostic biomarker and offered a new therapeutic target for diffuse large B-cell lymphoma patients.

Silencing PPA1 inhibits human epithelial ovarian cancer metastasis by suppressing the Wnt/β-catenin signaling pathway

Inorganic pyrophosphatase (PPA1) activity is a key determinant of cellular inorganic pyrophosphate levels, and its expression is correlated with growth of several solid tumors. To investigate this relationship, we first examined PPA1 expression in human epithelial ovarian cancer (EOC) samples, and found that PPA1 was overexpressed in tumors from EOC patients. Higher PPA1 levels correlated with advanced grades, stages, and poor survival in EOC patients. Examination of PPA1 function in EOC revealed that silencing PPA1 inhibited EOC migration, epithelial-mesenchymal transition (EMT), and metastasis in vitro and in vivo. In addition, PPA1 may promote the dephosphorylation and translocation of β-catenin. These results demonstrate that silencing PPA1 inhibits EOC metastasis by suppressing the Wnt/β-catenin signaling pathway. Strategies for downregulating PPA1 may have therapeutic potential for the prevention and treatment of EOC.Inorganic pyrophosphatase (PPA1) activity is a key determinant of cellular inorganic pyrophosphate levels, and its expression is correlated with growth of several solid tumors. To investigate this relationship, we first examined PPA1 expression in human epithelial ovarian cancer (EOC) samples, and found that PPA1 was overexpressed in tumors from EOC patients. Higher PPA1 levels correlated with advanced grades, stages, and poor survival in EOC patients. Examination of PPA1 function in EOC revealed that silencing PPA1 inhibited EOC migration, epithelial-mesenchymal transition (EMT), and metastasis in vitro and in vivo. In addition, PPA1 may promote the dephosphorylation and translocation of β-catenin. These results demonstrate that silencing PPA1 inhibits EOC metastasis by suppressing the Wnt/β-catenin signaling pathway. Strategies for downregulating PPA1 may have therapeutic potential for the prevention and treatment of EOC.

Clinical significance and functional validation of PPA1 in various tumors

The aim of the study was to detect PPA1 expression in various tumors and to investigate the relationship between PPA1 expression and clinicopathological parameters to further analyze its clinical significance. Immunohistochemical staining detected PPA1 expression in 305 noncancerous tissues and 675 tumor tissues, which included 12 different tumor types. QPCR and western blot examined PPA1 expression in tumor‐derived cell lines including those derived from liver, breast, lung, and ovarian cancers. Cell proliferation and apoptosis assays were used to investigate PPA1‐regulated cell growth in tumor cells. Finally, a bioinformatics analysis was used to verify the role of PPA1 in carcinogenesis. Among the 12 types of tumors, PPA1 expression was significantly higher in lung and ovarian cancers (P < 0.001). In lung cancer, PPA1 expression was associated with tumor size, patients’ age, and smoking status, whereas in ovarian cancer, PPA1 expression was associated with pathological grade (P < 0.05). Moreover, we found that PPA1 expression was up‐regulated in lung and ovarian cancer cell lines compared with nontumor cells. In addition, suppression of PPA1 expression by RNA interference in lung and ovarian cancer cells showed increased cell apoptosis and decreased cell proliferation, which was mediated by TP53 and p21 signaling. Notably, a bioinformatics analysis was used to verify the function of PPA1 in the development and progression of tumors. PPA1 expression is significantly higher in many tumors, especially those of lung and ovarian origin, which suggests that PPA1 plays an important role in carcinogenesis and in the development of some tumors.

TLR4 Promotes Breast Cancer Metastasis via Akt/GSK3β/β-Catenin Pathway upon LPS Stimulation

Bacteria/virus‐induced chronic inflammation is involved in both tumor initiation and tumor progression. Toll‐like receptor 4 (TLR4) has been implicated in the development of several types of cancer. In this study, we explored the impact of TLR4 activation by lipopolysaccharide (LPS) on breast cancer metastasis and associated signaling molecules. We first examined TLR4 expression levels in breast tissue using a human breast tissue microarray and breast cell lines. We then studied the role of TLR4 activation by LPS stimulation in breast cancer metastasis using both in vitro and in vivo models. Finally, we investigated signaling molecules involved in the process using Western blotting and fluorescent immunohistochemistry staining. The results showed that TLR4 expression levels increased in breast cancer tissue compared to normal breast tissue. In addition, our results also showed that TLR4 pathway activation by LPS stimulation in MCF7 and MDA‐MB‐231 breast cancer cells caused the following actions: (1) promotes migration of breast cancer cells, (2) triggers the β‐catenin signaling pathway via PI3K/Akt/GSK3β, and (3) promotes transcription of downstream β‐catenin target genes leading to breast cancer metastasis. This study substantiates and further extends the relationship between TLR4 activation by LPS and breast cancer using both in vitro and in vivo models. The results suggest that the Akt/GSK3β/β‐catenin signal transduction pathway may serve as a viable clinical treatment target in breast cancer. Anat Rec, 300:1219–1229, 2017.