Smad4 inhibits cell migration via suppression of JNK activity in human pancreatic carcinoma PANC-1 cells

S100 calcium‑binding protein A16 suppresses the osteogenic differentiation of rat bone marrow mesenchymal stem cells by inhibiting SMAD family member 4 signaling

Osteogenesis is a complex process of bone formation regulated by various factors, yet its underlying molecular mechanisms remain incompletely understood. The present study aimed to investigate the role of S100A16, a novel member of the S100 protein family, in the osteogenic differentiation of rat bone marrow mesenchymal stem cells (BMSCs) and uncover a novel Smad4-mitogen-activated protein kinase (MAPK)/Jun N-terminal kinase (JNK) signaling axis. In the present study, the expression level of S100A16 in bone tissues and BMSCs from ovariectomized rats was evaluated and then the impact of S100A16 silencing on osteogenic differentiation was examined. Increased S100A16 expression was observed in bone tissues and BMSCs from ovariectomized rats, and S100A16 silencing promoted osteogenic differentiation. Further transcriptomic sequencing revealed that the Smad4 pathway was involved in S100A16 silencing-induced osteogenesis. The results of western blot analysis revealed that S100A16 overexpression not only downregulated Smad4 but also activated MAPK/JNK signaling, which was validated by treatment with MAPK and JNK inhibitors U0126 and SP600125. Overall, in the present study, the novel regulatory factors influencing osteogenic differentiation were elucidated and mechanistic insights that could aid in the development of targeted therapeutic strategies for patients with osteoporosis were provided.

Gamma radiation assisted green synthesis of hesperidin-reduced graphene oxide nanocomposite targeted JNK/SMAD4/MMP2 signaling pathway

In this study, a novel method for the fabrication of hesperidin/reduced graphene oxide nanocomposite (RGOH) with the assistance of gamma rays is reported. The different RGOHs were obtained by varying hesperidin concentrations (25, 50, 100, and 200 wt.%) in graphene oxide (GO) solution. Hesperidin concentrations (25, 50, 100, and 200 wt.%) in graphene oxide (GO) were varied to produce the various RGOHs. Upon irradiation with 80 kGy from γ-Ray, the successful reduction of GO occurred in the presence of hesperidin. The reduction process was confirmed by different characterization techniques such as FTIR, XRD, HRTEM, and Raman Spectroscopy. A cytotoxicity study using the MTT method was performed to evaluate the cytotoxic-anticancer effects of arbitrary RGOH on Wi38, CaCo2, and HepG2 cell lines. The assessment of RGOH's anti-inflammatory activity, including the monitoring of IL-1B and IL-6 activities as well as NF-kB gene expression was done. In addition, the anti-invasive and antimetastatic properties of RGOH, ICAM, and VCAM were assessed. Additionally, the expression of the MMP2-9 gene was quantified. The assessment of apoptotic activity was conducted by the detection of gene expressions related to BCl2 and P53. The documentation of the JNK/SMAD4/MMP2 signaling pathway was ultimately accomplished. The findings of our study indicate that RGOH therapy has significant inhibitory effects on the JNK/SMAD4/MMP2 pathway. This suggests that it could be a potential therapeutic option for cancer.

LINC00909 up-regulates pluripotency factors and promotes cancer stemness and metastasis in pancreatic ductal adenocarcinoma by targeting SMAD4

BACKGROUND

Pancreatic cancer stem cells are crucial for tumorigenesis and cancer metastasis. Presently, long non-coding RNAs were found to be associated with Pancreatic Ductal Adenocarcinoma stemness characteristics but the underlying mechanism is largely known. Here, we aim to explore the function of LINC00909 in regulating pancreatic cancer stemness and cancer metastasis.

METHODS

The expression level and clinical characteristics of LINC00909 were verified in 80-paired normal pancreas and Pancreatic Ductal Adenocarcinoma tissues from Guangdong Provincial People's Hospital cohort by in situ hybridization. RNA sequencing of PANC-1 cells with empty vector or vector encoding LINC00909 was experimented for subsequent bioinformatics analysis. The effect of LINC00909 in cancer stemness and metastasis was examined by in vitro and in vivo experiments. The interaction between LINC00909 with SMAD4 and the pluripotency factors were studied.

RESULTS

LINC00909 was generally upregulated in pancreatic cancer tissues and was associated with inferior clinicopathologic features and outcome. Over-expression of LINC00909 enhanced the expression of pluripotency factors and cancer stem cells phenotype, while knock-down of LINC00909 decreased the expression of pluripotency factors and cancer stem cells phenotype. Moreover, LINC00909 inversely regulated SMAD4 expression, knock-down of SMAD4 rescued the effect of LINC00909-deletion inhibition on pluripotency factors and cancer stem cells phenotype. These indicated the effect of LINC00909 on pluripotency factors and CSC phenotype was dependent on SMAD4 and MAPK/JNK signaling pathway, another downstream pathway of SMAD4 was also activated by LINC00909. Specifically, LINC00909 was localized in the cytoplasm in pancreatic cancer cells and decreased the stability the SMAD4 mRNA. Finally, we found over-expression of LINC00909 not only accelerated tumor growth in subcutaneous mice models, but also facilitated tumorigenicity and spleen metastasis in orthotopic mice models.

CONCLUSION

We demonstrate LINC00909 inhibits SMAD4 expression at the post-transcriptional level, which up-regulates the expression of pluripotency factors and activates the MAPK/JNK signaling pathway, leading to enrichment of cancer stem cells and cancer metastasis in pancreatic cancer.

JNK signaling as a target for anticancer therapy

The JNKs are members of mitogen-activated protein kinases (MAPK) which regulate many physiological processes including inflammatory responses, macrophages, cell proliferation, differentiation, survival, and death. It is increasingly clear that the continuous activation of JNKs has a role in cancer development and progression. Therefore, JNKs represent attractive oncogenic targets for cancer therapy using small molecule kinase inhibitors. Studies showed that the two major JNK proteins JNK1 and JNK2 have opposite functions in different types of cancers, which need more specification in the design of JNK inhibitors. Some of ATP- competitive and ATP non-competitive inhibitors have been developed and widely used in vitro, but this type of inhibitors lack selectivity and inhibits phosphorylation of all JNK substrates and may lead to cellular toxicity. In this review, we summarized and discussed the strategies of JNK binding inhibitors and the role of JNK signaling in the pathogenesis of different solid and hematological malignancies.

SMAD4 and the TGFβ Pathway in Patients with Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer death worldwide. PDAC is an aggressive disease with an 11-month median overall survival and a five-year survival of less than 5%. Incidence of PDAC is constantly increasing and is predicted to become the second leading cause of cancer in Western countries within a decade. Despite research and therapeutic development, current knowledge about PDAC molecular mechanisms still needs improvements and it seems crucial to identify novel therapeutic targets. Genomic analyses of PDAC revealed that transforming growth factor β (TGFβ) signaling pathways are modified and the SMAD4 gene is altered in 47% and 60% of cases, respectively, highlighting their major roles in PDAC development. TGFβ can play a dual role in malignancy depending on the context, sometimes as an inhibitor and sometimes as an inducer of tumor progression. TGFβ signaling was identified as a potent inducer of epithelial-to-mesenchymal transition (EMT), a process that confers migratory and invasive properties to epithelial cells during cancer. Therefore, aberrant TGFβ signaling and EMT are linked to promoting PDAC aggressiveness. TGFβ and SMAD pathways were extensively studied but the mechanisms leading to cancer promotion and development still remain unclear. This review aims to describe the complex role of SMAD4 in the TGFβ pathway in patients with PDAC.

TMEFF2 inhibits pancreatic cancer cells proliferation, migration, and invasion by suppressing phosphorylation of the MAPK signaling pathway

Purpose

This paper studied the effect of TMEFF2 expression on pancreatic cancer and its mechanism.

Methods

A total of 72 pancreatic cancer patients were enrolled. AsPC1 and Panc1 cells were transfected. SB203580 was used to treat AsPC1 cells. CCK8 assay, colony formation analysis, Transwell experiment and Tunel test were performed. In vivo studies in nude mice were conducted. Immunohistochemistry, qRT-PCR and Western blot were used to detect genes expression.

Results

TMEFF2 was downregulated in pancreatic cancer tissues and cells (P<0.001). Low TMEFF2 expression was associated with larger tumor size and advanced stage and poor differentiation (P<0.01). Compared with the NC group, AsPC1 and Panc1 cells of the TMEFF2 group exhibited much lower OD450 values, colony number, tumor volume and weight, migration and invasion cell numbers, obviously higher E-cadherin protein expression, lower Snail, Vimentin, MMP-2 and MMP-9 proteins expression, lower phosphorylation level of MAPK signaling pathway, and more apoptotic cells. AsPC1 cells of the SB203580 group showed much lower OD450 value when compared with the siTMEFF2 group. Significantly decreased colony number, migration and invasion number, higher E-cadherin protein expression and lower Snail, Vimentin, MMP-2 and MMP-9 proteins expression were found in AsPC1 cells of the siTMEFF2+ SB203580 group when compared with the siTMEFF2+ DMSO group.

Conclusion

TMEFF2 inhibits pancreatic cancer cells proliferation, migration, and invasion by suppressing the phosphorylation of the MAPK signaling pathway.

SMAD4 Y353C promotes the progression of PDAC

Background

SMAD4 is frequently inactivated and associated with a poor prognosis in pancreatic ductal adenocarcinoma (PDAC). Abnormal SMAD4 expression also plays an important role in the malignant progression of PDAC.

Methods

We investigated SMAD4 status in PDAC by immunohistochemical methods to explore the relationships between SMAD4 expression and clinicopathological features and then detected SMAD4 mutations by Sanger sequencing in 95 patients with PDAC to identify new mutation sites in PDAC. We further evaluated the effects of a missense mutation, Y353C, in the SMAD4 MH2 domain, on cell proliferation and migration in vitro.

Results

Immunohistochemistry showed that the expression of SMAD4 in PDAC carcinoma tissue was significantly lower than that in normal pancreatic tissue, and negative SMAD4 expression was closely related to tumour diameter, staging, lymph node metastasis and differentiation. Sanger sequencing analysis showed that the rate of SMAD4 mutation was 11.8% in 85 PDAC cases, and the novel SMAD4 Y353C missense mutation identified in this study promoted cell migration and invasion without affecting cell proliferation in vitro. Furthermore, SMAD4 Y353C resulted in reduced expression of E-cadherin and increased expression of Vimentin compared with wild-type SMAD4 overexpression.

Conclusion

This study supports the key role of SMAD4 as a tumour suppressor gene in PDAC and shows that SMAD4 Y353C is associated with poor progression of PDAC.

Overexpressed microRNA-136 works as a cancer suppressor in gallbladder cancer through suppression of JNK signaling pathway via inhibition of MAP2K4

In recent studies, microRNAs (miRs) have been widely explored as important regulators in tumor suppression. miR-136 has been suggested to participate in tumor inhibition through control of vital cellular processes, such as angiogenesis, proliferation, and apoptosis. This study aimed to evaluate the effects of overexpressed miR-136 by transferring mimics in gallbladder cancer (GBC) and to assess the functional role of miR-136 in GBC cell behaviors with the involvement of the mitogen-activated protein kinase kinase 4 (MAP2K4)-dependent JNK signaling pathway. Differentially expressed miRs associated with GBC were screened using microarray expression profiles, which identified that miR-136 expression was decreased in GBC. Furthermore, MAP2K4 was validated as a target gene of miR-136. To uncover functional relevance regarding miR-136 and MAP2K4 in GBC, cultured GBC cell lines were prepared to transfect with mimic, inhibitor, siRNA, or vectors. At the same time, the transfected GBC cells were inoculated into nude mice to validate findings in vivo. The obtained results demonstrated that overexpressed miR-136 inhibited angiogenesis and cell proliferation and promoted apoptosis in GBC cell lines in vitro, accompanied by impeded cellular tumorigenicity in nude mice via the suppression of MAP2K4. Moreover, the overexpression of MAP2K4 and the activation of the JNK signaling pathway reversed the inhibitory effects of miR-136 on the angiogenesis and tumorigenicity of GBC cells. Together, our results indicated that overexpressed miR-136 attenuates angiogenesis and enhances cell apoptosis in GBC via the JNK signaling pathway by downregulating the expression of MAP2K4.NEW & NOTEWORTHY This study is based on previous studies suggesting the tumor-suppressive role of microRNA (miR)-136 in various cancers. We aim to clarify whether miR-136 could function as a tumor suppressor in gallbladder cancer (GBC) and an underlying mechanism. In vitro and in vivo assays delineated that the tumor-suppressive role of miR-136 in GBC is achieved through inactivation of the JNK signaling pathway by downregulation of MAP2K4.

Loss of Wnt4 expression inhibits the odontogenic potential of dental pulp stem cells through JNK signaling in pulpitis

Dental pulp stem cell (DPSC)-based odontogenic regeneration in inflammatory conditions is important in the process of pulpitis. DPSCs have been reported to lose potential for odontogenic regeneration in inflammatory conditions. This study aims to determine the mechanism of impaired odontogenic differentiation of DPSCs in an inflammatory microenvironment. We regulated Wnt4 expression using recombinant lentiviral Wnt4 and Wnt4 siRNA. Alkaline phosphatase (ALP) and Alizarin red S (ARS) staining as well as Real-Time PCR were performed to evaluate the osteogenic differentiation potential of DPSCs with either upregulated or downregulated Wnt4. Furthermore, SP600125 was used to inhibit the potential downstream factor JNK1, and the osteogenic differentiation ability of DPSCs was evaluated. As shown, Wnt4 was downregulated in DPSCs under inflammatory conditions. Inhibition of Wnt4 expression in DPSCs negatively regulated odontogenic differentiation. Overexpression of Wnt4 in LPS-treated DPSCs promoted odontogenic differentiation. In addition, JNK1 was responsible for Wnt4-mediated odontogenic differentiation of DPSCs. Taken together, Wnt4 may function by affecting JNK signaling pathways in the process of impaired odontogenic regeneration by DPSCs under inflammatory conditions.

Upregulation of miR-146a-5p is associated with increased proliferation and migration of vascular smooth muscle cells in aortic dissection

BACKGROUND

This study aimed to investigate whether miR-146a-5p was involved in the pathogenesis of thoracic aortic dissection (AD) via regulating the biological function of vascular smooth muscle cells (VSMCs).

METHODS

Circulating miR-146a-5p level was measured by quantitative polymerase chain reaction (qPCR) in AD patients and healthy controls. Human dissected aortic samples were obtained from patients with thoracic AD Stanford type A undergoing surgical repair, and normal control samples were from organ donors who died from nonvascular diseases. The expression level of miR-146a-5p was detected using qPCR in each sample. The expression of SMAD4, which is involved in the TGF-β pathway and indicated as the target gene of miR-146a-5p, was measured by qPCR and Western blot analysis at the mRNA level and protein level, respectively. Subsequently, VSMCs were transfected with miR-146a-5p mimics or inhibitors in vitro. VSMC proliferation and migration were detected using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and Transwell assay, respectively. Flow cytometry was used to identify apoptosis. The expression of SMAD4 in VSMCs was determined using qPCR and Western blot analysis.

RESULTS

Plasma level of miR-146a-5p is significantly higher in the AD group as compared with the control group. The expression of miR-146a-5p was significantly upregulated in dissected aorta compared with controls (P < 0.05). The overexpression of miR-146a-5p significantly induced VSMC proliferation and migration in vitro.

CONCLUSIONS

The expression of SMAD4 was modulated by miR-146a-5p. miR-146a-5p induced VSMC proliferation and migration through targeting SMAD4 and hence might be potentially involved in the development of AD.

miR-146a promotes cell migration and invasion in melanoma by directly targeting SMAD4

Previous studies have explored the functions of microRNA (miR)-146a in different types of cancer through mediating different targets. However, the roles of miR-146a in malignant melanoma (MM) cell migration and invasion remain largely elusive. In the present study, the potential molecular function of miR-146a in MM was investigated. Reverse transcription-quantitative polymerase chain reaction was utilized to detect miR-146a expression in MM tissues and cell lines. A Transwell assay was performed to confirm the ability of migration and invasion. A luciferase assay and biological analysis were used to predict and determine the targets of miR-146a. The expression of miR-146a was upregulated in melanoma tissues and cell lines. Clinicopathological analysis indicated that the miR-146a level was negatively correlated with the progression of melanoma. Abnormal expression of miR-146a promoted cell migration and invasion in MM cells. Additionally, it was also observed that Mothers against decapentaplegic homolog 4 (SMAD4) was a novel target of miR-146a in MM. SMAD4 was negatively associated with miR-146a in MM and abnormal expression of SMAD4 attenuated miR-146a-mediated promotion of cell migration and invasion. In conclusion, miR-146a functioned as an oncogene by directly targeting SMAD4 and it may be a novel diagnostic and therapeutic marker of MM.

Ethyl acetate extract from Inula helenium L. inhibits the proliferation of pancreatic cancer cells by regulating the STAT3/AKT pathway

Sesquiterpene lactones are bioactive compounds that have been identified as responsible for the anticancer activity of the medicinal herb, Inula helenium L. (IHL). However, the mechanisms of action involved in the anti‑pancreatic cancer activity of IHL have yet to be elucidated. The present study used an optimized extraction strategy to obtain sesquiterpene lactones from IHL (the resulting product termed ethyl acetate extract of IHL; EEIHL), and examined the potential mechanisms involved in the anti‑pancreatic cancer activity of EEIHL. Ethanol and ethyl acetate were used to extract sesquiterpene lactones from IHL to give the final product EEIHL. Cell Counting Kit‑8, colony formation and Annexin V/propidium iodide assays were used to detect the anti‑proliferative activity of EEIHL. Cell migration was determined with a wound healing assay. mRNA and protein expression levels were analyzed by reverse transcription‑quantitative polymerase chain reaction and western blot analyses, respectively. It was identified that low concentrations of EEIHL caused CFPAC‑1 cell cycle arrest in the G0/G1 phase, whereas high concentrations of EEIHL induced mitochondria‑dependent apoptosis. In addition, EEIHL could inhibit the phosphorylation of the signal transducer and activator of transcription (STAT)3/AKT pathway, potentially resulting in impeded cell mobility. In conclusion, EEIHL could activate mitochondrial‑dependent apoptosis and inhibit cell migration through the STAT3/AKT pathway in CFPAC-1 cells.

The Role of Platelet-Derived ADP and ATP in Promoting Pancreatic Cancer Cell Survival and Gemcitabine Resistance

Platelets have been demonstrated to be vital in cancer epithelial-mesenchymal transition (EMT), an important step in metastasis. Markers of EMT are associated with chemotherapy resistance. However, the association between the development of chemoresistance, EMT, and the contribution of platelets to the process, is still unclear. Here we report that platelets regulate the expression of (1) human equilibrative nucleoside transporter 1 (hENT1) and (2) cytidine deaminase (CDD), markers of gemcitabine resistance in pancreatic cancer. Human ENT1 (hENT1) is known to enable cellular uptake of gemcitabine while CDD deactivates gemcitabine. Knockdown experiments demonstrate that Slug, a mesenchymal transcriptional factor known to be upregulated during EMT, regulates the expression of hENT1 and CDD. Furthermore, we demonstrate that platelet-derived ADP and ATP regulate Slug and CDD expression in pancreatic cancer cells. Finally, we demonstrate that pancreatic cancer cells express the purinergic receptor P2Y₁₂, an ADP receptor found mainly on platelets. Thus ticagrelor, a P2Y₁₂ inhibitor, was used to examine the potential therapeutic effect of an ADP receptor antagonist on cancer cells. Our data indicate that ticagrelor negated the survival signals initiated in cancer cells by platelet-derived ADP and ATP. In conclusion, our results demonstrate a novel role of platelets in modulating chemoresistance in pancreatic cancer. Moreover, we propose ADP/ATP receptors as additional potential drug targets for treatment of pancreatic cancer.

SMAD4 Loss Is Associated with Cetuximab Resistance and Induction of MAPK/JNK Activation in Head and Neck Cancer Cells

Purpose: We previously demonstrated an association between decreased SMAD4 expression and cetuximab resistance in head and neck squamous cell carcinoma (HNSCC). The purpose of this study was to further elucidate the clinical relevance of SMAD4 loss in HNSCC.Experimental Design: SMAD4 expression was assessed by IHC in 130 newly diagnosed and 43 patients with recurrent HNSCC. Correlative statistical analysis with clinicopathologic data was also performed. OncoFinder, a bioinformatics tool, was used to analyze molecular signaling in TCGA tumors with low or high SMAD4 mRNA levels. The role of SMAD4 was investigated by shRNA knockdown and gene reconstitution of HPV-negative HNSCC cell lines in vitro and in vivoResults: Our analysis revealed that SMAD4 loss was associated with an aggressive, HPV-negative, cetuximab-resistant phenotype. We found a signature of prosurvival and antiapoptotic pathways that were commonly dysregulated in SMAD4-low cases derived from TCGA-HNSCC dataset and an independent oral cavity squamous cell carcinoma (OSCC) cohort obtained from GEO. We show that SMAD4 depletion in an HNSCC cell line induces cetuximab resistance and results in worse survival in an orthotopic mouse model in vivo We implicate JNK and MAPK activation as mediators of cetuximab resistance and provide the foundation for the concomitant EGFR and JNK/MAPK inhibition as a potential strategy for overcoming cetuximab resistance in HNSCCs with SMAD4 loss.Conclusions: Our study demonstrates that loss of SMAD4 expression is a signature characterizing the cetuximab-resistant phenotype and suggests that SMAD4 expression may be a determinant of sensitivity/resistance to EGFR/MAPK or EGFR/JNK inhibition in HPV-negative HNSCC tumors. Clin Cancer Res; 23(17); 5162-75. ©2017 AACR.