PDK1 induces JunB, EMT, cell migration and invasion in human gallbladder cancer

Decoding dysregulated angiogenesis in HTLV-1 asymptomatic carriers compared to healthy individuals

Human T-cell lymphotropic virus type 1 (HTLV-1) is the first identified human retrovirus responsible for two significant diseases: HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and adult T-cell leukemia/lymphoma (ATLL). Although the majority of infected individuals remain asymptomatic carriers, a small percentage may develop ATLL or HAM/TSP. In tumorigenesis, a crucial process is angiogenesis, which involves the formation of new blood vessels. However, the precise mechanism of HTLV-1 associated angiogenesis remains unclear. This study aims to investigate the gene regulation involved in the angiogenesis signaling pathway associated with HTLV-1 infection. The research enrolled 20 male participants, including asymptomatic carriers and healthy individuals. Blood samples were collected and screened using ELISA for HTLV-1 confirmation, and PCR was performed for both Tax and HBZ for validation. RNA extraction and cDNA synthesis were carried out, followed by RT-qPCR analysis targeting cellular genes involved in angiogenesis. Our findings indicate that gene expression related to angiogenesis was elevated in HTLV-1 ACs patients. However, the differences in gene expression of the analyzed genes, including HSP27, Paxillin, PDK1, PTEN, RAF1, SOS1, and VEGFR2 between ACs and healthy individuals were not statistically significant. This suggests that although angiogenesis-related genes may show increased expression in HTLV-1 infection, they might not be robust indicators of ATLL progression in asymptomatic carriers. The results of our study demonstrate that angiogenesis gene expression is altered in ACs of HTLV-1, indicating potential involvement of angiogenesis in the early stages before ATLL development. While we observed elevated angiogenesis gene expression in ACs, the lack of statistical significance between ACs and healthy individuals suggests that these gene markers may not be sufficient on their own to predict the development of ATLL in asymptomatic carriers.

Phenotypic Characterization of Circulating Tumor Cells Isolated from Non-Small and Small Cell Lung Cancer Patients

In the present study, we evaluated the expression of JUNB and CXCR4 in circulating tumor cells (CTCs) of lung cancer patients and investigated whether these proteins have prognostic clinical relevance. Peripheral blood from 30 patients with non-small-cell lung cancer (NSCLC) was filtered using ISET membranes, and cytospins from 37 patients with small-cell lung cancer (SCLC) were analyzed using confocal and VyCAP microscopy. Both JUNB and CXCR4 were expressed in the vast majority of lung cancer patients. Interestingly, the phenotypic patterns differed between NSCLC and SCLC patients; the (CK+/JUNB+/CXCR4+) phenotype was present in 50% of NSCLC vs. 71% of SCLC patients. Similarly, the (CK+/JUNB+/CXCR4−) was present in 44% vs. 71%, the (CK+/JUNB−/CXCR4+) in 6% vs. 71%, and the (CK+/JUNB−/CXCR4−) phenotype in 38% vs. 84%. In NSCLC, the presence of ≥1 CTCs with the (CK+/JUNB+/CXCR4+) phenotype was associated with worse progression-free survival (PFS) (p = 0.007, HR = 5.21) while ≥2 with poorer overall survival (OS) (p < 0.001, HR = 2.16). In extensive stage SCLC patients, the presence of ≥4 CXCR4-positive CTCs was associated with shorter OS (p = 0.041, HR = 5.01). Consequently, JUNB and CXCR4 were expressed in CTCs from lung cancer patients, and associated with patients’ survival, underlying their key role in tumor progression.

PDK1 Inhibitor BX795 Improves Cisplatin and Radio-Efficacy in Oral Squamous Cell Carcinoma by Downregulating the PDK1/CD47/Akt-Mediated Glycolysis Signaling Pathway

Background: Oral squamous cell carcinoma (OSCC) has a high prevalence and predicted global mortality rate of 67.1%, necessitating better therapeutic strategies. Moreover, the recurrence and resistance of OSCC after chemo/radioresistance remains a major bottleneck for its effective treatment. Molecular targeting is one of the new therapeutic approaches to target cancer. Among a plethora of targetable signaling molecules, PDK1 is currently rising as a potential target for cancer therapy. Its aberrant expression in many malignancies is observed associated with glycolytic re-programming and chemo/radioresistance. Methods: Furthermore, to better understand the role of PDK1 in OSCC, we analyzed tissue samples from 62 patients with OSCC for PDK1 expression. Combining in silico and in vitro analysis approaches, we determined the important association between PDK1/CD47/LDHA expression in OSCC. Next, we analyzed the effect of PDK1 expression and its connection with OSCC orosphere generation and maintenance, as well as the effect of the combination of the PDK1 inhibitor BX795, cisplatin and radiotherapy in targeting it. Results: Immunohistochemical analysis revealed that higher PDK1 expression is associated with a poor prognosis in OSCC. The immunoprecipitation assay indicated PDK1/CD47 binding. PDK1 ligation significantly impaired OSCC orosphere formation and downregulated Sox2, Oct4, and CD133 expression. The combination of BX795 and cisplatin markedly reduced in OSCC cell’s epithelial-mesenchymal transition, implying its synergistic effect. p-PDK1, CD47, Akt, PFKP, PDK3 and LDHA protein expression were significantly reduced, with the strongest inhibition in the combination group. Chemo/radiotherapy together with abrogation of PDK1 inhibits the oncogenic (Akt/CD47) and glycolytic (LDHA/PFKP/PDK3) signaling and, enhanced or sensitizes OSCC to the anticancer drug effect through inducing apoptosis and DNA damage together with metabolic reprogramming. Conclusions: Therefore, the results from our current study may serve as a basis for developing new therapeutic strategies against chemo/radioresistant OSCC.

Possible involvement of the Hedgehog and PDPK1-Akt pathways in the growth and migration of small-cell lung cancer

BACKGROUND

Small-cell lung cancer (SCLC) accounts for approximately 15% to 20% of all lung cancers, and it is the leading cause of tumor-related deaths globally. This study explored the molecular mechanisms underlying the development of SCLC.

METHODS

The correlations of phosphoinositide-dependent kinase-1 (PDPK1), p-Akt, and Hedgehog expression with patient characteristics were analyzed using SCLC specimens, and their expression was measured in BEAS-2B cells (control) and the SCLC cell lines H82, H69, H446, H146, and H526. Transfection experiments were performed to inhibit or activate gene expression in cells. We then measured the proliferation and migration of H146 cells.

RESULTS

PDPK1, p-Akt, and Hedgehog expression was significantly higher in SCLC tissues, and their expression was correlated with patient characteristics. p-Akt expression was significantly correlated with Hedgehog expression. In H146 cells, PDPK1 and p-Akt were significantly upregulated. Silencing of PDPK1 or Akt and inhibition of Hedgehog significantly inhibited the proliferation and migration of H146 cells. PDPK1 and Akt affected Hedgehog expression, but Hedgehog did not affect PDPK1 or p-Akt expression.

CONCLUSIONS

The interaction between the PDPK1-Akt pathway and the Hedgehog pathway influences the prognosis, growth, and migration of SCLC.

Pyruvate dehydrogenase kinases (PDKs): an overview toward clinical applications

Pyruvate dehydrogenase kinase (PDK) can regulate the catalytic activity of pyruvate decarboxylation oxidation via the mitochondrial pyruvate dehydrogenase complex, and it further links glycolysis with the tricarboxylic acid cycle and ATP generation. This review seeks to elucidate the regulation of PDK activity in different species, mainly mammals, and the role of PDK inhibitors in preventing increased blood glucose, reducing injury caused by myocardial ischemia, and inducing apoptosis of tumor cells. Regulations of PDKs expression or activity represent a very promising approach for treatment of metabolic diseases including diabetes, heart failure, and cancer. The future research and development could be more focused on the biochemical understanding of the diseases, which would help understand the cellular energy metabolism and its regulation by pharmacological effectors of PDKs.

SPRY4-IT1 promotes survival of colorectal cancer cells through regulating PDK1-mediated glycolysis

Colorectal cancer (CRC) becomes the third leading cause of cancer-related deaths worldwide recently. The prognosis of CRC is still poor in decades, and targeted therapy is still a potential effective treatment. Long non-coding RNAs (lncRNAs) could regulate series of cellular functions and developmental processes. LncRNA-SPRY4-IT1 (GenBank ID AK024556) is derived from an intron of the SPRY4 gene, which was highly expressed in melanoma cells and affected the progression of multiple types of cancers. However, the mechanism of SPRY4-IT1 in CRC progression remains unclear. Herein, we found the high level of SPRY4-IT1 in human colorectal cancer (CRC) tissues and cells, and correlated with patients' prognosis. We further noticed that SPRY4-IT1 regulated CRC cell growth and glycolysis, and promoting PDK1 expression. Our data further confirmed that SPRY4-IT1 regulated CRC progression targeting PDK1. We therefore thought SPRY4-IT1 could serve as a promising molecular target for the treatment of CRC.

CXCR4 and JUNB double-positive disseminated tumor cells are detected frequently in breast cancer patients at primary diagnosis

Background:

The chemokine receptor CXCR4 and the transcription factor JUNB, expressed on a variety of tumor cells, seem to play an important role in the metastatic process. Since disseminated tumor cells (DTCs) in the bone marrow (BM) have been associated with worse outcomes, we evaluated the expression of CXCR4 and JUNB in DTCs of primary, nonmetastatic breast cancer (BC) patients before the onset of any systemic treatment.

Methods:

Bilateral BM (10 ml) aspirations of 39 hormone receptor (HR)-positive, HER2-negative BC patients were assessed for the presence of DTCs using the following combination of antibodies: pan-cytokeratin (A45-B/B3)/CXCR4/JUNB. An expression pattern of the examined proteins was created using confocal laser scanning microscopy, Image J software and BC cell lines.

Results:

CXCR4 was overexpressed in cancer cells and DTCs, with the following hierarchy of expression: SKBR3 > MCF7 > DTCs > MDA-MB231. Accordingly, the expression pattern of JUNB was: DTCs > MDA-MB231 > SKBR3 > MCF7. The mean intensity of CXCR4 (6411 ± 334) and JUNB (27725.64 ± 470) in DTCs was statistically higher compared with BM hematopoietic cells (2009 ± 456, p = 0.001; and 11112.89 ± 545, p = 0.001, respectively). The (CXCR4+JUNB+CK+) phenotype was the most frequently detected [90% (35/39)], followed by the (CXCR4–JUNB+CK+) phenotype [36% (14/39)]. However, (CXCR4+JUNB–CK+) tumor cells were found in only 5% (3/39) of patients. Those patients harboring DTCs with the (CXCR4+JUNB+CK+) phenotype revealed lower overall survival (Cox regression: p = 0.023).

Conclusions:

(CXCR4+JUNB+CK+)-expressing DTCs, detected frequently in the BM of BC patients, seem to identify a subgroup of patients at higher risk for relapse that may be considered for close follow up.

Downregulation of TNFRSF19 and RAB43 by a novel miRNA, miR-HCC3, promotes proliferation and epithelial-mesenchymal transition in hepatocellular carcinoma cells

Tumor necrosis factor receptor superfamily 19 (TNFRSF19) is a transmembrane protein involved in tumorigenesis. RAB43 is a small molecule GTP-binding protein contributing to the occurrence and development of tumors. However, TNFRSF19/RAB43 dysregulation and their role in hepatocellular carcinoma cells are unknown. Herein, we found that TNFRSF19 and RAB43 were downregulated in hepatocellular carcinoma tissues. TNFRSF19/RAB43 overexpression suppressed, whereas TNFRSF19/RAB43 knockdown promoted cell proliferation and epithelial-mesenchymal transition (EMT) of hepatocellular carcinoma cells. Previously, using deep sequencing technology, a new miRNA, miR-HCC3, was identified and found to suppress the expression of TNFRSF19 and RAB43 by binding to their 3'untranslated regions (3'UTRs) directly. miR-HCC3 was upregulated in hepatocellular carcinoma (HCC) tissues compared with adjacent noncancerous tissues and promoted proliferation and epithelial-mesenchymal transition in HCC cells. Furthermore, TNFRSF19/RAB43 suppressed but miR-HCC3 promoted tumor growth in vivo. Collectively, our results indicated that downregulation of TNFRSF19 and RAB43 by miR-HCC3 contributes to oncogenic activities in HCC, which sheds light on tumorigenesis and might provide potential therapeutic targets for HCC.

The prognostic value of JUNB-positive CTCs in metastatic breast cancer: from bioinformatics to phenotypic characterization

Background

Circulating tumor cells (CTCs) are important for metastatic dissemination of cancer. They can provide useful information, regarding biological features and tumor heterogeneity; however, their detection and characterization are difficult due to their limited number in the bloodstream and their mesenchymal characteristics. Therefore, new biomarkers are needed to address these questions.

Methods

Bioinformatics functional enrichment analysis revealed a subgroup of 24 genes, potentially overexpressed in CTCs. Among these genes, the chemokine receptor CXCR4 plays a central role. After prioritization according to the CXCR4 corresponding pathways, five molecules (JUNB, YWHAB, TYROBP, NFYA, and PRDX1) were selected for further analysis in biological samples. The SKBR3, MDA-MB231, and MCF7 cell lines, as well as PBMCs from normal (n = 10) blood donors, were used as controls to define the expression pattern of all the examined molecules. Consequently, 100 previously untreated metastatic breast cancer (mBC) patients (n = 100) were analyzed using the following combinations of antibodies: CK (cytokeratin)/CXCR4/JUNB, CK/NFYA/ΥWHΑΒ (14-3-3), and CK/TYROBP/PRDX1. A threshold value for every molecule was considered the mean expression in normal PBMCs.

Results

Quantification of CXCR4 revealed overexpression of the receptor in SKBR3 and in CTCs, following the subsequent scale (SKBR3>CTCs>Hela>MCF7>MDA-MB231). JUNB was also overexpressed in CTCs (SKBR3>CTCs>MCF7>MDA-MB231>Hela). According to the defined threshold for each molecule, CXCR4-positive CTCs were identified in 90% of the patients with detectable tumor cells in their blood. In addition, 65%, 75%, 14.3%, and 12.5% of the patients harbored JUNB-, TYROBP-, NFYA-, and PRDX-positive CTCs, respectively. Conversely, none of the patients revealed YWHAB-positive CTCs. Interestingly, JUNB expression in CTCs was phenotypically and statistically enhanced compared to patients’ blood cells (p = 0.002) providing a possible new biomarker for CTCs. Furthermore, the detection of JUNB-positive CTCs in patients was associated with poorer PFS (p = 0.015) and OS (p = 0.002). Moreover, JUNB staining of 11 primary and 4 metastatic tumors from the same cohort of patients revealed a dramatic increase of JUNB expression in metastasis.

Conclusions

CXCR4, JUNB, and TYROBP were overexpressed in CTCs, but only the expression of JUNB was associated with poor prognosis, providing a new biomarker and a potential therapeutic target for the elimination of CTCs.

Electronic supplementary material

The online version of this article (10.1186/s13058-019-1166-4) contains supplementary material, which is available to authorized users.

Expression of PDK-1 and DMBT1 in the thyroid carcinoma and its clinicopathological significance

This study was designed to explore the expression of phosphoinositide-dependent protein kinase 1 (PDK-1), deleted in malignant brain tumors (DMBT1) in the thyroid carcinoma. A total of 87 fresh samples of thyroid carcinoma from surgical resection in The Second People's Hospital of Lianyungang from June 2016 to March 2018 were collected for the ELISA to detect the protein expression of PDK-1 and DMBT1. Then the pathological significance of the expression of PDK-1 and DMBT1 in the thyroid carcinoma and the correlation between them were analyzed, using the ROC curve to study the diagnostic value of each index. The expression of PDK-1 in the thyroid carcinoma tissue was significantly higher than that in the normal thyroid tissue with a statistical difference between them (P<0.05); the expression of DMBT1 in the thyroid carcinoma was statistically significantly lower than that in the normal thyroid tissue (P<0.05); the PDK-1 and DMBT1 expressions were in negative correlation in the thyroid carcinoma (r=−0.889, P<0.001). The AUG, specificity and the sensitivity of the PDK-1 in diagnosing the thyroid carcinoma were 0.862, 86.21% and 78.16%, respectively; the AUG, specificity and the sensitivity of the DMBT1 in diagnosing the thyroid carcinoma were 0.708, 66.67% and 67.82%, respectively; while the AUG, the specificity and the sensitivity of the combination of PDK-1 and DMBT1 in diagnosing the thyroid carcinoma were 0.888, 89.66% and 81.61%. In conclusion, the occurrence and progression of the thyroid carcinoma were related to the high expression of the PDK-1 and the low expression of the DMBT1 in the thyroid carcinoma tissues, the two of which were in connection with factors involving lymph node metastasis, pathological type, neoplasm staging, and clinical staging. Thus, the combined detection of PDK-1 and DMBT1 could be used as an effective index to determine the occurrence of thyroid carcinoma.

Low expression of PDK1 inhibits renal cell carcinoma cell proliferation, migration, invasion and epithelial mesenchymal transition through inhibition of the PI3K-PDK1-Akt pathway

As the most commonly occurring form of primary renal tumor, renal cell carcinoma (RCC) is a malignancy accompanied by a high mortality rate. 3-phosphoinositide-dependent protein kinase 1 (PDK1) has been established as a protein target and generated considerable interest in both the pharmaceutical and academia industry. The aim of the current study was to investigate the effect of si-PDK1 on the RCC cell apoptosis, proliferation, migration, invasion and epithelial mesenchymal transition (EMT) in connection with the PI3K-PDK1-Akt pathway. Microarray analysis from the GEO database was adopted to identify differentially expressed genes (DEGs) related to RCC, after which the positive expression of the PDK1 protein in tissue was determined accordingly. The optimal silencing si-RNA was subsequently selected and RCC cell lines 786-O and A498 were selected and transfected with either a si-PDK1 or activator of the PI3K-PDK1-Akt pathway for grouping purposes. The mRNA and protein expressions of PDK1, the PI3K-PDK1-Akt pathway-, EMT- and apoptosis-related genes were then evaluated. The effect of si-PDK1 on cell proliferation, apoptosis, invasion and migration was then analyzed. Through microarray analysis of GSE6344, GSE53757, GSE14762 and GSE781, PDK1 was examined. PDK1 was determined to be highly expressed in RCC tissues. Si-PDK1 exhibited marked reductions in relation to the mRNA and protein expression of PDK1, PI3K, AKT as well as Vimentin while elevated mRNA and protein expressions of E-cadherin were detected, which ultimately suggested that cell migration, proliferation and invasion had been inhibited coupled with enhanced levels of cell apoptosis. While a notable observation was made highlighting that the PI3K-PDK1-Akt pathway antagonized the effect of PDK1 silencing. Taken together, the key observations of this study provide evidence suggesting that high expressions of PDK1 are found in RCC, while highlighting that silencing PDK1 could inhibit RCC cell proliferation, migration, invasion and EMT by repressing the PI3K-PDK1-Akt pathway.

The PDK1/c‑Jun pathway activated by TGF‑β induces EMT and promotes proliferation and invasion in human glioblastoma

Glioblastoma multiforme (GBM) is the most common primary malignant tumor affecting the human brain. Despite improvements in therapeutic technologies, patients with GBM have a poor clinical result and the molecular mechanisms responsible for the development of GBM have not yet been fully elucidated. 3-phosphoinositide dependent protein kinase 1 (PDK1) is upregulated in various tumors and promotes tumor invasion. In glioma, transforming growth factor-β (TGF‑β) promotes cell invasion; however, whether TGF‑β directly regulates PDK1 protein and promotes proliferation and invasion is not yet clear. In this study, PDK1 levels were measured in glioma tissues using tissue microarray (TMA) by immunohistochemistry (IHC) and RT‑qPCR. Kaplan-Meier analyses were used to calculate the survival rate of patients with glioma. In vitro, U251 and U87 glioma cell lines were used for functional analyses. Cell proliferation and invasion were analyzed using siRNA transfection, MTT assay, RT‑qPCR, western blot analysis, flow cytometry and invasion assay. In vivo, U251 glioma cell xenografts were established. The results revealed that PDK1 protein was significantly upregulated in glioma tissues compared with non-tumorous tissues. Furthermore, the higher PDK1 levels were associated with a large tumor size (>5.0 cm), a higher WHO grade and a shorter survival of patients with GBM. Univariate and multivariate analyses indicated that PDK1 was an independent prognostic factor. In vivo, PDK1 promoted glioma tumor xenograft growth. In vitro, functional analyses confirmed that TGF‑β upregulated PDK1 protein expression and PDK1 promoted cell migration and invasion, and functioned as an oncogene in GBM, by upregulating c‑Jun protein and inducing epithelial-mesenchymal transition (EMT). c‑Jun protein were overexpressed in glioma tissues and positively correlated with PDK1 levels. Moreover, our findings were further validated by the online Oncomine database. On the whole, the findings of this study indicate that in GBM, PDK1 functions as an oncogene, promoting proliferation and invasion.

Blocking CDK1/PDK1/β-Catenin signaling by CDK1 inhibitor RO3306 increased the efficacy of sorafenib treatment by targeting cancer stem cells in a preclinical model of hepatocellular carcinoma

Rationale: Hepatocellular carcinoma (HCC) is an aggressive malignant solid tumor wherein CDK1/PDK1/β-Catenin is activated, suggesting that inhibition of this pathway may have therapeutic potential. Methods: CDK1 overexpression and clinicopathological parameters were analyzed. HCC patient-derived xenograft (PDX) tumor models were treated with RO3306 (4 mg/kg) or sorafenib (30 mg/kg), alone or in combination. The relevant signaling of CDK1/PDK1/β-Catenin was measured by western blot. Silencing of CDK1 with shRNA and corresponding inhibitors was performed for mechanism and functional studies. Results: We found that CDK1 was frequently augmented in up to 46% (18/39) of HCC tissues, which was significantly associated with poor overall survival (p=0.008). CDK1 inhibitor RO3306 in combination with sorafenib treatment significantly decreased tumor growth in PDX tumor models. Furthermore, the combinatorial treatment could overcome sorafenib resistance in the HCC case #10 PDX model. Western blot results demonstrated the combined administration resulted in synergistic down-regulation of CDK1, PDK1 and β-Catenin as well as concurrent decreases of pluripotency proteins Oct4, Sox2 and Nanog. Decreased CDK1/PDK1/β-Catenin was associated with suppression of epithelial mesenchymal transition (EMT). In addition, a low dose of RO3306 and sorafenib combination could inhibit 97H CSC growth via decreasing the S phase and promoting cells to enter into a Sub-G1 phase. Mechanistic and functional studies silencing CDK1 with shRNA and RO3306 combined with sorafenib abolished oncogenic function via downregulating CDK1, with downstream PDK1 and β-Catenin inactivation. Conclusion: Anti-CDK1 treatment can boost sorafenib antitumor responses in PDX tumor models, providing a rational combined treatment to increase sorafenib efficacy in the clinic.

Long non-coding RNA UCA1 promotes gallbladder cancer progression by epigenetically repressing p21 and E-cadherin expression

A growing number of studies indicated that long non-coding RNAs (lncRNAs) determine some cellular processes in cancer, such as proliferation, metastasis and differentiation. Urothelial carcinoma associated 1 (UCA1), an lncRNA, had been reported for its overexpression and oncogenic effect on various human cancers. In this study, we found that UCA1 was significantly overexpressed in gallbladder cancer (GBC) and positively correlated with tumor size, lymph node metastasis, TNM stage and short survival time. Moreover, UCA1 promoted GBC cell proliferation and metastasis in vitro and tumor growth in vivo. Mechanically, we identified that UCA1 promoted GBC progression through recruiting enhancer of zeste homolog 2 (EZH2) to the promoter of p21 and E-cadherin, and epigenetically suppressing their transcript.

Identification of Epithelial-Mesenchymal Transition-related Target Genes Induced by the Mutation of Smad3 Linker Phosphorylation

Background

Smad3 linker phosphorylation plays essential roles in tumor progression and metastasis. We have previously reported that the mutation of Smad3 linker phosphorylation sites (Smad3-Erk/Pro-directed kinase site mutant constructs [EPSM]) markedly reduced the tumor progression while increasing the lung metastasis in breast cancer.

Methods

We performed high-throughput RNA-Sequencing of the human prostate cancer cell lines infected with adenoviral Smad3-EPSM to identify the genes regulated by Smad3-EPSM.

Results

In this study, we identified genes which are differentially regulated in the presence of Smad3-EPSM. We first confirmed that Smad3-EPSM strongly enhanced a capability of cell motility and invasiveness as well as the expression of epithelial-mesenchymal transition marker genes, CDH2, SNAI1, and ZEB1 in response to TGF-β1 in human pancreatic and prostate cancer cell lines. We identified GADD45B, CTGF, and JUNB genes in the expression profiles associated with cell motility and invasiveness induced by the Smad3-EPSM.

Conclusions

These results suggested that inhibition of Smad3 linker phosphorylation may enhance cell motility and invasiveness by inducing expression of GADD45B, CTGF, and JUNB genes in various cancers.

Epithelial-to-mesenchymal transition in gallbladder cancer: from clinical evidence to cellular regulatory networks

Gallbladder cancer (GBC), with late diagnosis, rapid disease progression and early metastasis, is a highly aggressive malignant tumor found worldwide. Patients with GBC have poor survival, low curative resection rates and early recurrence. For such a lethal tumor, uncovering the mechanisms and exploring new strategies to prevent tumor progression and metastasis are critically important. Epithelial-to-mesenchymal transition (EMT) has a prominent role in the early steps of tumor progression and metastasis by initiating polarized epithelial cell transition into motile mesenchymal cells. Accumulating evidence suggests that EMT can be modulated by the cooperation of multiple mechanisms affecting common targets. Signaling pathways, transcriptional and post-transcriptional regulation and epigenetic alterations are involved in the stepwise EMT regulatory network in GBC. Loss of epithelial markers, acquisition of mesenchymal markers and dysregulation of EMT-inducing transcription factors (EMT-TFs) have been observed and are associated with the clinicopathology and prognosis of GBC patients. Therefore, EMT may be a detectable and predictable event for predicting GBC progression and metastasis in the clinic. In this review, we will provide an overview of EMT from the clinical evidence to cellular regulatory networks that have been studied thus far in clinical and basic GBC studies.

Targeting PDK1 for Chemosensitization of Cancer Cells

Despite the rapid development in the field of oncology, cancer remains the second cause of mortality worldwide, with the number of new cases expected to more than double in the coming years. Chemotherapy is widely used to decelerate or stop tumour development in combination with surgery or radiation therapy when appropriate, and in many cases this improves the symptomatology of the disease. Unfortunately though, chemotherapy is not applicable to all patients and even when it is, there are many cases where a successful initial treatment period is followed by chemotherapeutic drug resistance. This is caused by a number of reasons, ranging from the genetic background of the patient (innate resistance) to the formation of tumour-initiating cells (acquired resistance). In this review, we discuss the potential role of PDK1 in the development of chemoresistance in different types of malignancy, and the design and application of potent inhibitors which can promote chemosensitization.

CCR7 mediates human breast cancer cell invasion, migration by inducing epithelial-mesenchymal transition and suppressing apoptosis through AKT pathway

Chemokine and the chemokine receptor have a key role in the tumor progress. Here, we supposed that CCR7 might induce the invasion, migration, and epithelial–mesenchymal transition (EMT) process of breast cancer. In this research, human breast cancer MCF‐7 and MDA‐MB‐231cells were treated with CCL19 and small‐interfering RNA (CCR7 siRNA) for activation and inhibition of CCR7, respectively. Cell invasion and transwell assays were used to detect the effect of CCR7 on invasion and migration. The results demonstrated that CCL19 mediated cell invasion and migration by inducing the EMT, with downregulation of E‐cadherin and up‐regulation of N‐cadherin and vimentin levels. On the other hand, knockdown of CCR7 revealed the changes compared with CCL19 group and the control group. Knockdown of CCR7 inhibits CCL19‐induced breast cancer cell proliferation, the cell cycle, migration, invasion and EMT. Moreover, we demonstrated that CCL19‐induced AKT phosphorylation; however, CCR7 siRNA suppressed CCL19‐induced AKT phosphorylation, a key regulator of tumor metastasis. In conclusion, all findings demonstrated that CCL19/CCR7 axis regulated EMT progress in breast cancer cells and mediated the tumor cell invasion and migration process via activation of AKT signal pathway. Our results suggested that CCR7 may regard as a therapeutic target for the breast cancer treatment.

Serine/Threonine Kinase 3-Phosphoinositide-Dependent Protein Kinase-1 (PDK1) as a Key Regulator of Cell Migration and Cancer Dissemination

Dissecting the cellular signaling that governs the motility of eukaryotic cells is one of the fundamental tasks of modern cell biology, not only because of the large number of physiological processes in which cell migration is crucial, but even more so because of the pathological ones, in particular tumor invasion and metastasis. Cell migration requires the coordination of at least four major processes: polarization of intracellular signaling, regulation of the actin cytoskeleton and membrane extension, focal adhesion and integrin signaling and contractile forces generation and rear retraction. Among the molecular components involved in the regulation of locomotion, the phosphatidylinositol-3-kinase (PI3K) pathway has been shown to exert fundamental role. A pivotal node of such pathway is represented by the serine/threonine kinase 3-phosphoinositide-dependent protein kinase-1 (PDPK1 or PDK1). PDK1, and the majority of its substrates, belong to the AGC family of kinases (related to cAMP-dependent protein kinase 1, cyclic Guanosine monophosphate-dependent protein kinase and protein kinase C), and control a plethora of cellular processes, downstream either to PI3K or to other pathways, such as RAS GTPase-MAPK (mitogen-activated protein kinase). Interestingly, PDK1 has been demonstrated to be crucial for the regulation of each step of cell migration, by activating several proteins such as protein kinase B/Akt (PKB/Akt), myotonic dystrophy-related CDC42-binding kinases alpha (MRCKα), Rho associated coiled-coil containing protein kinase 1 (ROCK1), phospholipase C gamma 1 (PLCγ1) and β3 integrin. Moreover, PDK1 regulates cancer cell invasion as well, thus representing a possible target to prevent cancer metastasis in human patients. The aim of this review is to summarize the various mechanisms by which PDK1 controls the cell migration process, from cell polarization to actin cytoskeleton and focal adhesion regulation, and finally, to discuss the evidence supporting a role for PDK1 in cancer cell invasion and dissemination.

Long non-coding RNA LINC00152 promotes gallbladder cancer metastasis and epithelial-mesenchymal transition by regulating HIF-1α via miR-138

Long non-coding RNA LINC00152 had been reported as an oncogene in gastric and hepatocellular cancer. In this study, we show that LINC00152 is overexpressed in gallbladder cancer (GBC) tissue samples and cell lines. The high LINC00152 levels correlated negatively with the overall survival time in GBC patients. Functionally, LINC00152 dramatically promoted cell migration, invasion and epithelial-mesenchymal transition (EMT) progression in vitro. In vivo, LINC00152 overexpression significantly promoted tumour peritoneal spreading and metastasis. Mechanistic analyses indicated that LINC00152 functions as a molecular sponge for miR-138, which directly suppresses the expression of hypoxia inducible factor-1α (HIF-1α). We revealed that miR-138 is a suppressor of GBC cell metastasis and EMT progression, and a similar phenomenon was observed in HIF-1α knockdown NOZ cells. Through binding to miR-138, LINC00152 has an oncogenic effect on GBC. Overall, our study suggested that the LINC00152/miR-138/HIF-1α pathway potentiates the progression of GBC, and LINC00152 may be a novel therapeutic target.

PDK1 promotes the inflammatory progress of fibroblast-like synoviocytes by phosphorylating RSK2

This study investigated the role of PDK1 in inflammatory response which is initiated by TNF-α and analyzed the association between PDK1 and RSK2. TNF-α were added into MH7A cells to induce inflammation condition. Through overexpressing or suppressing PDK1 in MH7A cells, the role of PDK1 in cell invasiveness and inflammatory factors was determined. Levels of MMPs protein and inflammatory cytokines were assessed with PDK1 siRNA and TNF-α treatment. Inhibition of RSK2 was used to investigate the function of RSK2 on PDK1-induced inflammation. The phosphorylation of RSK2 was detected when PDK1 was inhibited. Luciferase reporter assay was performed to detect the transcriptional activity of NF-κB. We found highly expressed PDK1 could promote cell invasion and secretion of IL-1β and IL-6 in MH7A cells. Inhibition of RSK2 reduced the PDK1-induced cell invasion and cytokines secretion in MH7A cells. In response to TNF-α, PDK1 could phosphorylate RSK2 and activated RSK2, then promoting the activation of NF-κB. This may be a possible therapeutic option of rheumatoid arthritis.

Correlation of PDK1 expression with clinicopathologic features and prognosis of hepatocellular carcinoma

Objective

To explore the clinical significance of 3-phosphoinositide-dependent protein kinase-1 (PDK1) expression in hepatocellular carcinoma (HCC) and its association with clinicopathologic features and prognosis in HCC patients.

Materials and methods

A total of 128 HCC patients who received radical resection were enrolled from Wenling Maternal and Child Health Care Hospital between May 2005 and December 2008, and tumor and adjacent tissue samples were collected. Expression of PDK1 was detected by immunohistochemistry method. Correlation of PDK1 expression with clinicopathological features and prognosis was determined by Spearman’s correlation analysis. Impact of expression of PDK1 on overall survival and recurrence was determined by Kaplan–Meier analysis.

Results

Immunohistochemistry results showed that PDK1 expression in HCC tissues was significantly higher than that in the corresponding adjacent cancer tissues. Univariate analysis showed that PDK1 messenger RNA expression can predict time to recurrence with diagnostic significance (P=0.001). Univariate analysis showed that alpha-fetoprotein level, tumor number, tumor encapsulation, microvascular invasion, and tumor–node–metastasis stage were also unfavorable prognostic variables for recurrence (P<0.05). Kaplan–Meier analysis showed that overexpression of PDK1 correlates with significantly shorter postoperative overall survival and higher recurrence rates (hazard ratio =2.68; 95% confidence interval: 2.46–4.42, P=0.001) in HCC patients after curative resection.

Conclusion

Our study indicated that PDK1 may serve as a candidate pro-oncogene and a potential prognostic biomarker for HCC.

Short-form Ron is a novel determinant of ovarian cancer initiation and progression

Short-form Ron (sfRon) is an understudied, alternative isoform of the full-length Ron receptor tyrosine kinase. In contrast to Ron, which has been shown to be an important player in many cancers, little is known about the role of sfRon in cancer pathogenesis. Here we report the striking discovery that sfRon expression is required for development of carcinogen-induced malignant ovarian tumors in mice. We also show that sfRon is expressed in several subtypes of human ovarian cancer including high-grade serous carcinomas, which is in contrast to no detectable expression in healthy ovaries. In addition, we report that introduction of sfRon into OVCAR3 cells resulted in epithelial-to-mesenchymal transition, activation of the PI3K and PDK1 pathway, and inhibition of the MAPK pathway. We demonstrated that sfRon confers an aggressive cancer phenotype in vitro characterized by increased proliferation and migration, and decreased adhesion of ovarian cancer cells. Moreover, the in vivo studies show that OVCAR3 tumors expressing sfRon exhibit significantly more robust growth and spreading to the abdominal cavity when compared with the parental sfRon negative OVCAR3 cells. These data suggest that sfRon plays a significant role in ovarian cancer initiation and progression, and may represent a promising therapeutic target for ovarian cancer treatment.

B4GALT3 up-regulation by miR-27a contributes to the oncogenic activity in human cervical cancer cells

β-1,4-Galactosyltransferase III (B4GALT3) is an enzyme responsible for the generation of poly-N-acetyllactosamine and is involved in tumorigenesis. However, B4GALT3-dysregulation and its role in cervical cancer cells are unknown. Herein, we found that B4GALT3 was upregulated in cervical cancer tissues compared to adjacent non-tumor tissues. B4GALT3-overexpression promoted, whereas B4GALT3-knockdown suppressed the cellular migration, invasion and EMT of HeLa and C33A cervical cancer cells. To explore the mechanism of dysregulation, B4GALT3 was predicted to be a target of miR-27a. EGFP and pGL3-promoter reporter assay showed miR-27a binds to B4GALT3 3'UTR region but enhanced its expression. RT-qPCR showed miR-27a was also upregulated and presented positive correlation with B4GALT3-expression in cervical cancer tissues. miR-27a-overexpression promoted, but blocking-miR-27a repressed these malignancies in HeLa and C33A cells. Furthermore, shR-B4GALT3 counteracted the promotion of malignancies induced by miR-27a, suggesting miR-27a upregulates B4GALT3 to enhance tumorigenic activities. In addition, we found that B4GALT3 significantly enhances β1-integrin stability, thus mediating promotion of B4GALT3 on malignancy in cervical cancer cells. Altogether, our findings evidenced that B4GALT3 upregulated by miR-27a contributes to the tumorigenic activities by β1-integrin pathway and might provide potential biomarkers for cervical cancer.

miR-497 inhibits epithelial mesenchymal transition in breast carcinoma by targeting Slug

Epithelial to mesenchymal transition (EMT) is a critical step in the growth and dissemination of malignant diseases, including breast cancer. It is known that microRNAs (miRNAs) play important roles in the regulation of tumor properties in cancers. However, whether miR-497 contributes to EMT in breast cancer cells remains unknown. Our study demonstrated that the expression of miR-497 was significantly decreased in human breast cancer cell lines and breast cancer specimens. In breast cancer cells, EMT was inhibited and promoted by the over-expression as well as depletion of miR-497, respectively. Dual-Luciferase ReporterAassay confirmed that Slug was a direct target of miR-497. The upregulation of miR-497 in breast cancer cells suppressed cell proliferation and induced apoptosis both in vitro and in vivo. Correlation analysis indicated that miR-497 was highly negatively correlated with Slug expression in breast cancer specimens. The knockdown of Slug expression in breast cancer cells significantly suppressed cell proliferation and promoted apoptosis. Our results suggested that the expression of miR-497 is significantly correlated with EMT in breast cancer cells by regulating Slug at the transcriptional as well as translational levels. Therefore, targeting miR-497 may provide a novel strategy for the treatment of breast cancer.