Phospholipid Phosphatase 4 promotes proliferation and tumorigenesis, and activates Ca2+-permeable Cationic Channel in lung carcinoma cells.

BACKGROUND: Phospholipid phosphatase 4 (PPAPDC1A or PLPP4) has been demonstrated to be involved in the malignant process of many cancers. The purpose of this study was to investigate the clinical significance and biological roles of PLPP4 in lung carcinoma. METHODS: PLPP4 expression was examined in 8 paired lung carcinoma tissues by real-time PCR and in 265 lung carcinoma tissues by immunohistochemistry (IHC). Statistical analysis was performed to evaluate the clinical correlation between PLPP4 expression and clinicopathological features and survival in lung carcinoma patients. In vitro and in vivo assays were performed to assess the biological roles of PLPP4 in lung carcinoma. Fluorescence-activated cell sorting, Western blotting and luciferase assays were used to identify the underlying pathway through which PLPP4 silencing mediates biological roles in lung carcinoma. RESULTS: PLPP4 is differentially elevated in lung adenocarcinoma (ADC) and lung squamous cell carcinoma (SQC) tissues. Statistical analysis demonstrated that high expression of PLPP4 significantly and positively correlated with clinicopathological features, including pathological grade, T category and stage, and poor overall and progression-free survival in lung carcinoma patients. Silencing PLPP4 inhibits proliferation and cell cycle progression in vitro and tumorigenesis in vivo in lung carcinoma cells. Our results further reveal that PLPP4 silencing inhibits Ca2+-permeable cationic channel, suggesting that downregulation of PLPP4 inhibits proliferation and tumorigenesis in lung carcinoma cells via reducing the influx of intracellular Ca2+. CONCLUSION: Our results indicate that PLPP4 may hold promise as a novel marker for the diagnosis of lung carcinoma and as a potential therapeutic target to facilitate the development of novel treatment for lung carcinoma.

Prostate tumour overexpressed-1 promotes tumourigenicity in human breast cancer via activation of Wnt/ß-catenin signalling.

Breast cancer is the most common malignancy in females. The presence of cancer stem cells (CSCs) is the main cause of local and distant tumour recurrence and is associated with poor outcome in breast cancer. However, the molecular mechanisms underlying the maintenance of CSCs remain largely unknown. This study demonstrates that prostate tumour overexpressed-1 (PTOV1) enhances the CSC population and augments the tumourigenicity of breast cancer cells both in vitro and in vivo. Moreover, PTOV1 suppresses transcription of Dickkopf-1 (DKK1) by recruiting histone deacetylases and subsequently reducing DKK1 promoter histone acetylation, followed by activation of Wnt/ß-catenin signalling. Restoration of DKK1 expression in PTOV1-overexpressing cells counteracts the effects of PTOV1 on Wnt/ß-catenin activation and the CSC population. Collectively, these results suggest that PTOV1 positively regulates the Wnt/ß-catenin signalling pathway and enhances tumourigenicity in breast cancer; this novel mechanism may represent a therapeutic target for breast cancer. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

C14ORF166 overexpression is associated with pelvic lymph node metastasis and poor prognosis in uterine cervical cancer.

C14ORF166 (chromosome 14 open reading frame 166) is a transcriptional repressor related to the regulation of centrosome architecture. However, the role of C14ORF166 in the development and progression of cancer remains largely unknown. The aim of this study was to investigate the expression and clinicopathological significance of C14ORF166 in cervical cancer. C14ORF166 expression was analyzed using quantitative real-time PCR (RT-PCR) and Western blotting in cervical cancer cell lines and eight paired cervical cancer samples and the adjacent normal tissues. Immunohistochemistry was used to analyze C14ORF166 protein expression in 148 clinicopathologically characterized cervical cancer specimens. Statistical analyses were performed to evaluate the relationship between the expression of C14ORF166 and clinicopathologic features and prognosis. C14ORF166 mRNA and protein expression were significantly upregulated in cervical cancer cell lines and tissue samples (P < 0.05). Immunohistochemical analysis revealed a high expression of C14ORF166 was observed in 39.9 % (59/148) of the cervical cancer specimens; the remaining samples expressed low levels or did not express any detectable C14ORF166. The chi-square test indicated that high-level expression of C14ORF166 was significantly associated with International Federation of Gynecology and Obstetrics (FIGO) stage (P < 0.001), vital status (P = 0.026), tumor size (P = 0.034), serum squamous cell carcinoma antigen level (SCC-Ag; P = 0.035), and pelvic lymph node metastasis (P < 0.001). Patients with highly expressed C14ORF166 showed a tendency to receive postoperative chemotherapy (P = 0.005) and postoperative radiation (P = 0.008). Furthermore, high C14ORF166 expression was associated with poorer overall survival compared to low C14ORF166 expression, and C14ORF166 was a significant prognostic factor in univariate and multivariate analysis (P < 0.05). High C14ORF166 expression had prognostic value for poor outcome in cervical cancer. C14ORF166 may represent a biomarker of pelvic lymph node metastasis and enable the identification of high-risk patients along with selection of appropriate treatment strategies.

Overexpression of chromosome 14 open reading frame 166 correlates with disease progression and poorer prognosis in human NPC.

Chromosome 14 open reading frame 166 (c14orf166) contributes to regulation of centrosome architecture, transcription initiation, and RNA elongation and processing. However, the role of c14orf166 in human cancer remains unclear. This study aimed to investigate the expression and clinicopathological significance of c14orf166 in nasopharyngeal carcinoma (NPC). Real-time PCR and Western blotting analyses were employed to examine c14orf166 expression in immortalized primary nasopharyngeal epithelial cells (NP69), six NPC cell lines, three paired tumor samples and the adjacent noncancerous tissues from the same patients, and three additional tumor samples. Immunohistochemistry was performed to examine c14orf166 protein expression in archived paraffin-embedded tumor samples from 109 patients with clinicopathologically confirmed NPC. The association of c14orf166 expression with clinicopathological features and survival outcomes was assessed. C14orf166 messenger RNA and protein expression were upregulated in NPC cell lines and human tumor tissues compared to NP69 cells and noncancerous tissue samples, respectively. Immunohistochemical analyses revealed 104/109 (95.4 %) of the NPC tissue samples expressed c14orf166. High expression of c14orf166 (cutoff score >6) was significantly associated with gender (P = 0.016), clinical stage (P = 0.010), T classification (P = 0.013), N classification (P = 0.029), distant metastasis (P < 0.001), vital status (P = 0.001), and treatment method (P = 0.028; chi-square test). High c14orf166 expression was associated with significantly shorter overall survival (OS) and disease-free survival (DFS) than low c14orf166 expression. Multivariate analysis revealed c14orf166 was an independent prognostic indicator of OS and DFS in all patients (P = 0.046, P = 0.006) and was associated with poor OS and DFS in the subgroups with advanced clinical stage (P = 0.037, P = 0.001), lymph node metastasis (P = 0.001, P < 0.001), and T3-T4 disease (P = 0.005, P = 0.001), respectively. C14orf166 is overexpressed and may represent a novel prognostic factor in NPC.

Transducin ß-like 1 X-linked receptor 1 suppresses cisplatin sensitivity in nasopharyngeal carcinoma via activation of NF-κB pathway.

BACKGROUND: Transducin ß-like 1 X-linked receptor 1 (TBL1XR1) is an important transcriptional cofactor involved in the regulation of many signaling pathways, and is associated with carcinogenesis and tumor progression. However, the precise role of TBL1XR1 in these processes is not well understood. METHODS: We detected the expression of TBL1XR1 protein and mRNA in nasopharyngeal carcinoma (NPC) cell lines and biopsies by western blotting, real-time PCR and immunohistochemical staining (IHC). Overexpression of TBL1XR1 in NPC enhanced chemoresistance to cisplatin using two NPC cell lines in vitro and in vivo. RESULTS: TBL1XR1 was upregulated in NPC cell lines and clinical samples. The expression of TBL1XR1 was correlated with several clinicopathological factors including clinical stage, T classification, N classification and patient survival. Univariate and multivariate analysis revealed that TBL1XR1 was an independent prognostic factor for patient survival. In vitro and in vivo studies demonstrated that TBL1XR1 high expression induced resistance to cisplatin-induced apoptosis in NPC cells. Furthermore, we found that TBL1XR1 activated the NF-κB pathway and promoted transcription of genes downstream of NF-κB, especially anti-apoptotic genes. CONCLUSIONS: Upregulation of TBL1XR1 induces NPC cells resistance to cisplatin by activating the NF-κB pathway, and correlates with poor overall survival of NPC patients. TBL1XR1 has a pivotal role in NPC and could be a valuable prognostic factor as well as a novel biomarker for tailoring appropriate therapeutic regimes.

Overexpression of prostate tumor overexpressed 1 correlates with tumor progression and predicts poor prognosis in breast cancer.

BACKGROUND: Prostate tumor overexpressed 1 (PTOV1) was demonstrated to play an important role in cancer progression and was correlated with unfavorable clinical outcome. However, the clinical role of PTOV1 in cancer remains largely unknown. This study aimed to investigate the expression and clinicopathological significance of PTOV1 in breast cancer. METHODS: The mRNA and protein expression levels of PTOV1 were analyzed in 12 breast cancer cell lines and eight paired breast cancer tumors by semi-quantitative real time-PCR and western blotting, respectively. Immunohistochemistry was performed to assess PTOV1 protein expression in 169 paraffin-embedded, archived breast cancer samples. Survival analysis and Cox regression analysis were performed to investigate the clinicopathological significance of PTOV1 expression. RESULTS: Our data revealed that PTOV1 was frequently overexpressed in breast cancer cell lines compared to normal human breast epithelial cells and in primary breast cancer samples compared to adjacent noncancerous breast tissues, at both the mRNA and protein levels. Moreover, high expression of PTOV1 in breast cancer is strongly associated with clinicopathological characteristics and estrogen receptor expression status (P = 0.003). Breast cancer patients with higher PTOV1 expression had substantially shorter survival times than patients with lower PTOV1 expression (P < 0.001). Univariate and multivariate analysis revealed that PTOV1 might be an independent prognostic factor for breast cancer patients (P = 0.005). CONCLUSIONS: Our study showed that PTOV1 is upregulated in breast cancer cell lines and clinical samples, and its expression was positively associated with progression and aggressiveness of breast cancer, suggesting that PTOV1 could serve as an independent prognostic marker.

Downregulation of the circadian rhythm regulator HLF promotes multiple-organ distant metastases in non-small cell lung cancer through PPAR/NF-κb signaling.

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death due to its early recurrence and widespread metastatic potential. Accumulating studies have reported that dysregulation of circadian rhythms-associated regulators is implicated in the recurrence and metastasis of NSCLC. Therefore, identification of metastasis-associated circadian rhythm genes is clinically necessary. Here we report that the circadian gene hepatic leukemia factor (HLF), which was dramatically reduced in early-relapsed NSCLC tissues, was significantly correlated with early progression and distant metastasis in NSCLC patients. Upregulating HLF inhibited, while silencing HLF promoted lung colonization, as well as metastasis of NSCLC cells to bone, liver and brain in vivo. Importantly, downexpression of HLF promoted anaerobic metabolism to support anchorage-independent growth of NSCLC cells under low nutritional condition by activating NF-κB/p65 signaling through disrupting translocation of PPARα and PPARγ. Further investigations revealed that both genetic deletion and methylation contribute to downexpression of HLF in NSCLC tissues. In conclusion, our results shed light on a plausible mechanism by which HLF inhibits distant metastasis in NSCLC, suggesting that HLF may serve as a novel target for clinical intervention in NSCLC.

miR-892b Silencing Activates NF-κB and Promotes Aggressiveness in Breast Cancer.

The strength and duration of NF-κB signaling is tightly controlled at multiple levels under physiologic conditions, but the mechanism underlying constitutive activation of the NF-κB pathway in cancer remains unclear. In this study, we investigated miRNA-mediated regulation of the NF-κB cascade in breast cancer. We report that miR-892b expression was significantly downregulated in human breast cancer specimens and correlated with poor patient survival. Overexpression of miR-892b in breast cancer cells significantly decreased tumor growth, metastatic capacity, and the ability to induce angiogenesis, whereas miR-892b depletion enhanced these properties, in vitro and in vivo. Furthermore, we demonstrate that miR-892b attenuated NF-κB signaling by directly targeting and suppressing multiple mediators of NF-κB, including TRAF2, TAK1, and TAB3, and thus, miR-892b silencing in breast cancer cells sustains NF-κB activity. Moreover, miR-892b downregulation was attributed to aberrant hypermethylation of its promoter. Taken together, our results provide insight into a new mechanism by which NF-κB signaling becomes constitutively activated in breast cancer and suggest a tumor-suppressive role for miR-829b, prompting further investigation into miRNA mimics for cancer therapy.

Prostate Tumor Overexpressed 1 (PTOV1) Is a Novel Prognostic Marker for Nasopharyngeal Carcinoma Progression and Poor Survival Outcomes.

BACKGROUND: Prostate tumor overexpressed 1 (PTOV1) has been reported to contribute to increased cancer proliferation. However, the clinical significance of PTOV1 in the development and progression of nasopharyngeal carcinoma (NPC) is unclear. Our study aimed to investigate the expression pattern of PTOV1 in NPC and its correlation with clinicopathological features of patients. METHODS: Western blotting and real-time PCR were conducted to examine PTOV1 expression levels in NPC cell lines and biopsy tissues compared with normal controls. Immunohistochemistry (IHC) was performed to analyze PTOV1 protein expression in paraffin-embedded tissues from 123 patients. Statistical analyses were applied to evaluate the clinical significance of PTOV1 expression. RESULTS: PTOV1 mRNA and protein levels were upregulated in NPC cell lines and clinical samples. IHC analyses showed that PTOV1 was highly expressed in 68 (55.3%) of 123 NPC specimens. Statistical analysis revealed that PTOV1 expression was significantly correlated with clinical stage (P < 0.001), T classification (P = 0.042) and N classification (P = 0.001). Patients with a higher PTOV1 expression had shorter overall survival compared with those with a lower PTOV1 expression level, especially in lower N stage patients. Multivariate analyses suggested that PTOV1 expression was an independent prognostic marker for survival in NPC patients. CONCLUSIONS: Our data demonstrated that PTOV1 overexpression is associated with poor survival outcomes of NPC patients, especially in N0-1 patients. Hence, PTOV1 may help to detect early lymph node metastasis of NPC patients and serve as an independent prognostic biomarker for human NPC.

MiR-1207 overexpression promotes cancer stem cell-like traits in ovarian cancer by activating the Wnt/ß-catenin signaling pathway.

Wnt/ß-catenin signaling pathway is strictly controlled by multiple negative regulators. However, how tumor cells override the negative regulatory effects to maintain constitutive activation of Wnt/ß-catenin signaling, which is commonly observed in various cancers, remains puzzling. In current study, we reported that overexpression of miR-1207 in ovarian cancer activated Wnt/ß-catenin signaling by directly targeting and suppressing secreted Frizzled-related protein 1 (SFRP1), AXIN2 and inhibitor of ß-catenin and TCF-4 (ICAT), which are vital negative regulators of the Wnt/ß-catenin pathway. We found that the expression of miR-1207 was ubiquitously upregulated in both ovarian cancer tissues and cells, which inversely correlated with patient overall survival. Furthermore, overexpression of miR-1207 enhanced, while silencing miR-1207 reduced, stem cell-like traits of ovarian cancer cells in vitro and in vivo, including tumor sphere formation capability and proportion of SP+ and CD133+ cells. Importantly, upregulating miR-1207 promoted, while silencing miR-1207 inhibited, the tumorigenicity of ovarian cancer cells. Hence, our results suggest that miR-1207 plays a vital role in promoting the cancer stem cell-like phenotype in ovarian cancer and might represent a potential target for anti-ovarian cancer therapy.

miR-93 promotes cell proliferation in gliomas through activation of PI3K/Akt signaling pathway.

The PI3K/Akt signaling pathway is frequently activated in various human cancer types and plays essential roles in development and progression of cancers. Multiple regulators, such as phosphatase and tensin homolog (PTEN) and PH domain leucine rich repeat protein phosphatases (PHLPP), have also found to be involved in suppression of the PI3K/Akt signaling pathway. However, how suppressive effects mediated by these regulators are concomitantly disrupted in cancers, which display constitutively activated PI3K/Akt signaling, remains puzzling. In the present study, we reported that the expression of miR-93 was markedly upregulated in glioma cell lines and clinical glioma tissues. Statistical analysis revealed that miR-93 levels significantly correlated with clinicopathologic grade and overall survival in gliomas. Furthermore, we found that overexpressing miR-93 promoted, but inhibition of miR-93 reduced, glioma cell proliferation and cell-cycle progression. We demonstrated that miR-93 activated PI3K/Akt signaling through directly suppressing PTEN, PHLPP2 and FOXO3 expression via targeting their 3'UTRs. Therefore, our results suggest that miR-93 might play an important role in glioma progression and uncover a novel mechanism for constitutive PI3K/Akt activation in gliomas.

Downregulated miR-495 [Corrected] Inhibits the G1-S Phase Transition by Targeting Bmi-1 in Breast Cancer.

Bmi-1 (B cell-specific Moloney murine leukemia virus integration site 1) is upregulated in breast cancer and was involved in many malignant progressions of breast cells, including cell proliferation, stem cell pluripotency, and cancer initiation. However, the epigenetic regulatory mechanism of Bmi-1 in breast cancer remains unclear. After analysis of the ArrayExpress dataset GSE45666, we comparatively detected the expression levels of miR-495 in 9 examined breast cancer cell lines, normal breast epithelial cells and 8 pairs of fresh clinical tumor samples. Furthermore, to evaluate the effect of miR-495 on the progression of breast cancer, MCF-7 and MDA-MB-231 were transduced to stably overexpress miR-495. The 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, colony formation assays, 5-Bromo-2-deoxyUridine labeling and immunofluorescence, anchorage-independent growth ability assay, flow cytometry analysis, and luciferase assays were used to test the effect of miR-495 in MCF-7 and MDA-MB-231 cells in vitro. Xenografted tumor model was also used to evaluate the effect of miR-495 in breast cancer. Herein, we found that miR-495, a predicted regulator of Bmi-1, was frequently downregulated in malignant cells and tissues of breast. Upregulation of miR-495 significantly suppressed breast cancer cell proliferation and tumorigenicity via G1-S arrest. Further analysis revealed that miR-495 targeted Bmi-1 through its 3' untranslated region. Moreover, Bmi-1 could neutralize the suppressive effect of miR-495 on cell proliferation and tumorigenicity of breast cancer in vivo. These data suggested that miR-495 could inhibit the G1-S phase transition that leads to proliferation and tumorigenicity inhibition by targeting and suppressing Bmi-1 in breast cancer.

MicroRNA-500 sustains nuclear factor-κB activation and induces gastric cancer cell proliferation and resistance to apoptosis.

Ubiquitin deconjugation of key signalling molecules by deubiquitinases (DUBs) such as cylindromatosis (CYLD), A20, and OTU deubiquitinase 7B (OTUD7B) has emerged as an important regulatory mechanism in the downregulation of NF-κB signalling and homeostasis. However, how these serial negative regulations are simultaneously disrupted to result in constitutive activation of NF-κB signalling in cancers remains puzzling. Here, we report that the miR-500 directly repressed the expression of CYLD, OTUD7B, and the A20 complex component Tax1-binding protein 1 (TAX1BP1), leading to ubiquitin conjugation of receptor-interacting protein 1 (RIP1) and sustained NF-ĸB activation. Furthermore, we found that miR-500 promoted gastric cancer cell proliferation, survival, and tumorigenicity. Importantly, miR-500 was upregulated in gastric cancer and was highly correlated with malignant progression and poor survival. Hence, we report the uncovering of a novel mechanism for constitutive NF-κB activation, indicating the potentially pivotal role of miR-500 in the progression of gastric cancer.