A novel TOX3-WDR5-ABCG2 signaling axis regulates the progression of colorectal cancer by accelerating stem-like traits and chemoresistance.

The eradication of cancer stem cells (CSCs) with drug resistance confers the probability of local tumor control after chemotherapy or targeted therapy. As the main drug resistance marker, ABCG2 is also critical for colorectal cancer (CRC) evolution, in particular cancer stem-like traits expansion. Hitherto, the knowledge about the expression regulation of ABCG2, in particular its upstream transcriptional regulatory mechanisms, remains limited in cancer, including CRC. Here, ABCG2 was found to be markedly up-regulated in CRC CSCs (cCSCs) expansion and chemo-resistant CRC tissues and closely associated with CRC recurrence. Mechanistically, TOX3 was identified as a specific transcriptional factor to drive ABCG2 expression and subsequent cCSCs expansion and chemoresistance by binding to -261 to -141 segments of the ABCG2 promoter region. Moreover, we found that TOX3 recruited WDR5 to promote tri-methylation of H3K4 at the ABCG2 promoter in cCSCs, which further confers stem-like traits and chemoresistance to CRC by co-regulating the transcription of ABCG2. In line with this observation, TOX3, WDR5, and ABCG2 showed abnormal activation in chemo-resistant tumor tissues of in situ CRC mouse model and clinical investigation further demonstrated the comprehensive assessment of TOX3, WDR5, and ABCG2 could be a more efficient strategy for survival prediction of CRC patients with recurrence or metastasis. Thus, our study found that TOX3-WDR5/ABCG2 signaling axis plays a critical role in regulating CRC stem-like traits and chemoresistance, and a combination of chemotherapy with WDR5 inhibitors may induce synthetic lethality in ABCG2-deregulated tumors.

Nucleoporin TPR promotes tRNA nuclear export and protein synthesis in lung cancer cells.

The robust proliferation of cancer cells requires vastly elevated levels of protein synthesis, which relies on a steady supply of aminoacylated tRNAs. Delivery of tRNAs to the cytoplasm is a highly regulated process, but the machinery for tRNA nuclear export is not fully elucidated. In this study, using a live cell imaging strategy that visualizes nascent transcripts from a specific tRNA gene in yeast, we identified the nuclear basket proteins Mlp1 and Mlp2, two homologs of the human TPR protein, as regulators of tRNA export. TPR expression is significantly increased in lung cancer tissues and correlated with poor prognosis. Consistently, knockdown of TPR inhibits tRNA nuclear export, protein synthesis and cell growth in lung cancer cell lines. We further show that NXF1, a well-known mRNA nuclear export factor, associates with tRNAs and mediates their transport through nuclear pores. Collectively, our findings uncover a conserved mechanism that regulates nuclear export of tRNAs, which is a limiting step in protein synthesis in eukaryotes.

MED27 plays a tumor-promoting role in breast cancer progression by targeting KLF4.

The mediator complex usually cooperates with transcription factors to be involved in RNA polymerase II-mediated gene transcription. As one component of this complex, MED27 has been reported in our previous studies to promote thyroid cancer and melanoma progression. However, the precise function of MED27 in breast cancer development remains poorly understood. Here, we found that MED27 was more highly expressed in breast cancer samples than in normal tissues, especially in triple-negative breast cancer, and its expression level was elevated with the increase in pathological stage. MED27 knockdown in triple-negative breast cancer cells inhibited cancer cell metastasis and stemness maintenance, which was accompanied by downregulation of the expression of EMT- and stem traits-associated proteins, and vice versa in non-triple-negative breast cancer. Furthermore, MED27 knockdown sensitized breast cancer cells to epirubicin treatment by inducing cellular apoptosis and reducing tumorsphere-forming ability. Based on RNA-seq, we identified KLF4 as the possible downstream target of MED27. KLF4 overexpression reversed the MED27 silencing-mediated arrest of cellular metastasis and stemness maintenance capacity in breast cancer in vitro and in vivo. Mechanistically, MED27 transcriptionally regulated KLF4 by binding to its promoter region at positions -156 to +177. Collectively, our study not only demonstrated the tumor-promoting role of MED27 in breast cancer progression by transcriptionally targeting KLF4, but also suggested the possibility of developing the MED27/KLF4 signaling axis as a potential therapeutic target in breast cancer.

FLI1 regulates radiotherapy resistance in nasopharyngeal carcinoma through TIE1-mediated PI3K/AKT signaling pathway.

BACKGROUND: Radiotherapy resistance is the main cause of treatment failure in nasopharyngeal carcinoma (NPC), which leads to poor prognosis. It is urgent to elucidate the molecular mechanisms underlying radiotherapy resistance. METHODS: RNA-seq analysis was applied to five paired progressive disease (PD) and complete response (CR) NPC tissues. Loss-and gain-of-function assays were used for oncogenic function of FLI1 both in vitro and in vivo. RNA-seq analysis, ChIP assays and dual luciferase reporter assays were performed to explore the interaction between FLI1 and TIE1. Gene expression with clinical information from tissue microarray of NPC were analyzed for associations between FLI1/TIE1 expression and NPC prognosis. RESULTS: FLI1 is a potential radiosensitivity regulator which was dramatically overexpressed in the patients with PD to radiotherapy compared to those with CR. FLI1 induced radiotherapy resistance and enhanced the ability of DNA damage repair in vitro, and promoted radiotherapy resistance in vivo. Mechanistic investigations showed that FLI1 upregulated the transcription of TIE1 by binding to its promoter, thus activated the PI3K/AKT signaling pathway. A decrease in TIE1 expression restored radiosensitivity of NPC cells. Furthermore, NPC patients with high levels of FLI1 and TIE1 were correlated with poor prognosis. CONCLUSION: Our study has revealed that FLI1 regulates radiotherapy resistance of NPC through TIE1-mediated PI3K/AKT signaling pathway, suggesting that targeting the FLI1/TIE1 signaling pathway could be a potential therapeutic strategy to enhance the efficacy of radiotherapy in NPC.

Sample-Specific Perturbation of Gene Interactions Identifies Pancreatic Cancer Subtypes.

Pancreatic cancer is a highly fatal disease and an increasing common cause of cancer mortality. Mounting evidence now indicates that molecular heterogeneity in pancreatic cancer significantly impacts its clinical features. However, the dynamic nature of gene expression pattern makes it difficult to rely solely on gene expression alterations to estimate disease status. By contrast, biological networks tend to be more stable over time under different situations. In this study, we used a gene interaction network from a new point of view to explore the subtypes of pancreatic cancer based on individual-specific edge perturbations calculated by relative gene expression value. Our study shows that pancreatic cancer patients from the TCGA database could be separated into four subtypes based on gene interaction perturbations at the individual level. The new network-based subtypes of pancreatic cancer exhibited substantial heterogeneity in many aspects, including prognosis, phenotypic traits, genetic mutations, the abundance of infiltrating immune cell, and predictive therapeutic efficacy (chemosensitivity and immunotherapy efficacy). The new network-based subtypes were closely related to previous reported molecular subtypes of pancreatic cancer. This work helps us to better understand the heterogeneity and mechanisms of pancreatic cancer from a network perspective.

LINC00460 promotes pancreatic cancer progression by sponging miR-491-5p.

BACKGROUND: A growing body of studies have suggested that LINC00460 is instrumental in tumorigenesis and tumour progression. Nonetheless, the biological function and mechanisms of LINC00460 in pancreatic ductal adenocarcinoma (PDAC) remain vague. METHODS: Analysis based on public databases and a quantitative reverse transcription-polymerase chain reaction were performed to screen for differentially expressed lncRNAs in PDAC and to detect LINC00460 expression in PDAC cell lines and clinical samples. The survival of patients in the up-regulated and down-regulated LINC00460 expression groups was compared by using the Kaplan-Meier method. In addition, the potential biological functions of LINC00460 in PDAC were explored by cell counting kit-8, colony formation, flow cytometry and transwell assays. Furthermore, bioinformatics analysis, luciferase reporter assays and rescue experiments were applied to demonstrate the mechanism by which LINC00460 could directly bind to and inhibit miR-491-5p. RESULTS: LINC00460 is up-regulated in PDAC and correlates with adverse survival outcomes. The results of functional tests verified that LINC00460 knockdown inhibited both cell proliferation and cell migration. Additionally, knockdown led to G0/G1 cell cycle blockage and enhanced cell apoptosis. Mechanistic investigations revealed that LINC00460 directly binds to and attenuates the tumour suppressor miR-491-5p, thus accelerating PDAC progression. CONCLUSIONS: This research showed that LINC00460 is overexpressed in PDAC and correlates with adverse clinical outcomes. Additionally, LINC00460 promotes the aggressiveness of PDAC by targeting miR-491-5p. Thus, LINC00460 may serve as diagnostic biomarker of PDAC and a new target for PDAC therapy.

Synergistic Antitumor Effect of BKM120 with Prima-1Met Via Inhibiting PI3K/AKT/mTOR and CPSF4/hTERT Signaling and Reactivating Mutant P53.

BACKGROUND/AIMS: PI3KCA and mutant p53 are associated with tumorigenesis and the development of cancers. NVP-BKM120, a selective pan-PI3K inhibitor, exerts the antitumor activity by suppressing the PI3K signaling pathway. Prima-1Met, a low molecular weight compound, can rescue the gain-of-function of mutant p53 by restoring its transcriptional function. In this study, we investigated whether PI3K inhibition combined with mutant p53 reactivation could enhance the antitumor effect in thyroid cancer cells. METHODS: The effects of BKM120 and Prima-1Met on the proliferation, apoptosis, migration and invasion of thyroid cancer cells were measured by MTT, colony formation, flow cytometry, wound-healing and transwell assays, respectively. Thyroid differentiation was assessed by detecting the expression levels of specific markers using RT-PCR and Western blot. The in vivo antitumor efficacy was analyzed in a mouse xenograft model. RESULTS: The combinational treatment of BKM120 and Prima-1Met significantly enhanced the inhibitions of cell viability, colony formation, migration and invasion, and the induction of apoptosis in thyroid cell lines, and synergistically suppressed tumor xenograft growth by inhibiting the PI3K/Akt/mTOR and EMT signaling pathways, up-regulating p53 targeted genes, and triggering the release of cytochrome c. Moreover, the combination of BKM120 and Prima-1Met suppressed the stemlike traits of thyroid cancer cells and promoted their differentiation by upregulating the expression of thyroid-specific differentiation markers and repressing the expression of cancer stem cell markers. Furthermore, the mechanism study demonstrated that the combinational treatment synergistically abrogated the binding of CPSF4 at the promoter of hTERT and thus suppressed hTERT expression. Consistently, overexpression of hTERT rescued the inhibitions of cell viability, invasion and stem-like traits mediated by the combination of BKM120 and Prima-1Met. CONCLUSION: Our results showed that the combination of BKM120 with Prima-1Met synergistically suppressed the growth of thyroid cancer cells and tumor xenografts via inhibiting PI3K/Akt/mTOR and CPSF4/hTERT signaling and reactivating mutant p53.

RBFOX3 Regulates the Chemosensitivity of Cancer Cells to 5-Fluorouracil via the PI3K/AKT, EMT and Cytochrome-C/Caspase Pathways.

BACKGROUND/AIMS: RBFOX3, an RNA-binding fox protein, plays an important role in the differentiation of neuronal development, but its role in the chemosensitivity of hepatocellular carcinoma (HCC) to 5-FU is unknown. METHODS: In this study, we examined the biological functions of RBFOX3 and its effect on the chemosensitivity of HCC cells to 5-FU in vitro and in a mouse xenograft model. RESULTS: RBFOX3 was found to have elevated expression in HCC cell lines and tissue samples, and its knockdown inhibited HCC cell proliferation. Moreover, knockdown of RBFOX3 improved the inhibitory effect of 5-fluorouracil (5-FU) on cell proliferation, migration and invasion, and enhanced the apoptosis induced by 5-FU. However, overexpression of RBFOX3 reduced the inhibitory effect of 5-fluorouracil (5-FU) on cell proliferation, migration and invasion, and decreased the apoptosis induced by 5-FU. We further elucidated that RBFOX3 knockdown synergized with 5-FU to inhibit the growth and invasion of HCC cells through PI3K/AKT and epithelial-mesenchymal transition (EMT) signaling, and promote apoptosis by activating the cytochrome-c/caspase signaling pathway. Finally, we validated that RBFOX3 regulated 5-FU-mediated cytotoxicity in HCC in mouse xenograft models. CONCLUSIONS: The findings from this study indicate that RBFOX3 regulates the chemosensitivity of HCC to 5-FU in vitro and in vivo. Therefore, targeting RBFOX3 may improve the inhibition of HCC growth and progression by 5-FU, and provide a novel potential therapeutic strategy for HCC.

Activator Protein-2ß Promotes Tumor Growth and Predicts Poor Prognosis in Breast Cancer.

BACKGROUND/AIMS: Activator protein-2 (AP-2) transcription factors have been proved to be essential in maintaining cellular homeostasis and regulating the transformation from normal growth to neoplasia. However, the role of AP-2ß, a key member of AP-2 family, in breast cancer is rarely reported. METHODS: The effect of AP-2 on cell growth, migration and invasion in breast cancer cells were measured by MTT, colony formation, wound-healing and transwell assays, respectively. The expression levels of AP-2ß and other specific markers in breast cancer cell lines and tissue microarrays from the patients were detected using RT-PCR, Western blot and immunohistochemical staining. The regulation of AP-2ß on tumor growth in vivo was analyzed in a mouse xenograft model. RESULTS: We demonstrated the tumor-promoting function of AP-2ß in breast cancer. AP-2ß was found to be highly expressed in breast cancer cell lines and tumor tissues of breast cancer patients. The shRNA-mediated silencing of AP-2ß led to the dramatic inhibition of cell proliferation, colony formation ability, migration and invasiveness in breast cancer cells accompanied by the down-regulated expression of some key proteins involved in cancer progression, including p75, MMP-2, MMP-9, C-Jun, p-ERK and STAT3. Overexpression of AP-2ß markedly up-regulated the levels of these proteins. Consistent with the in vitro study, the silencing or overexpression of AP-2ß blocked or promoted tumor growth in the mice with xenografts of breast cancers. Notably, the high AP-2ß expression levels was correlated with poor prognosis and advanced malignancy in patients with breast cancer. CONCLUSIONS: Our study demonstrates that AP-2ß promotes tumor growth and predicts poor prognosis, and may represent a potential therapeutic target for breast cancer.

Downregulation of NMI promotes tumor growth and predicts poor prognosis in human lung adenocarcinomas.

BACKGROUND: N-myc (and STAT) interactor (NMI) plays vital roles in tumor growth, progression, and metastasis. In this study, we identified NMI as a potential tumor suppressor in lung cancer and explored its molecular mechanism involved in lung cancer progression. METHODS: Human lung cancer cell lines and a mouse xenograft model was used to study the effect of NMI on tumor growth. The expression of NMI, COX-2 and relevant signaling proteins were examined by Western blot. Tissue microarray immunohistochemical analysis was performed to assess the correlation between NMI and COX-2 expression in lung cancer patients. RESULTS: NMI was highly expressed in normal lung cells and tissues, but lowly expressed in lung cancer cells and tissues. Overexpression of NMI induced apoptosis, suppressed lung cancer cell growth and migration, which were mediated by up-regulation of the cleaved caspase-3/9 and down-regulation of phosphorylated PI3K/AKT, MMP2/MMP9, ß-cadherin, and COX-2/PGE2. In contrast, knockdown of NMI promoted lung cancer cell colony formation and migration, which were correlated with the increased expression of phosphorylated PI3K/AKT, MMP2/MMP9, ß-cadherin and COX-2/PGE2. Further study showed that NMI suppressed COX-2 expression through inhibition of the p50/p65 NF-κB acetylation mediated by p300. The xenograft lung cancer mouse models also confirmed the NMI-mediated suppression of tumor growth by inhibiting COX-2 signaling. Moreover, tissue microarray immunohistochemical analysis of lung adenocarcinomas also demonstrated a negative correlation between NMI and COX-2 expression. Kaplan-Meier analysis indicated that the patients with high level of NMI had a significantly better prognosis. CONCLUSIONS: Our study showed that NMI suppressed tumor growth by inhibiting PI3K/AKT, MMP2/MMP9, COX-2/PGE2 signaling pathways and p300-mediated NF-κB acetylation, and predicted a favorable prognosis in human lung adenocarcinomas, suggesting that NMI was a potential tumor suppressor in lung cancer.

ß-Catenin Cooperates with CREB Binding Protein to Promote the Growth of Tumor Cells.

BACKGROUND/AIMS: ß-catenin is an integral component of the canonical Wnt signaling pathway, and its mutations are an autosomal recessive cause of colorectal cancer (CRC), medulloblastoma (MDB), and ovarian cancer. Nevertheless, little is known about its function in lung cancers. METHODS: We first knocked down ß-catenin by siRNA to investigate its effects on lung cancer cell proliferation, migration and apoptosis. Then we verified the interaction between ß-catenin and CREB binding protein (CBP) by immunofluoresence and co-immunoprecipition assays. Finally, the expression of ß-catenin and CBP in human lung adenocarcinoma specimens were analyzed by immunohistochemistry assay. RESULTS: ß-catenin knockdown inhibited cell proliferation, promoted apoptosis and suppressed cell migration in A549 and H460 cells accompanied by the decreased expression of Myc, PCNA, VEGF, CD44, MMP-9, MMP-13 and activated bax/caspase-3 pathway. Furthermore, co-immunoprecipition and immunofluoresence analyses revealed that CBP interacted with ß-catenin and contributed to ß-catenin-mediated lung cancer cell growth. Abolishment of their interaction by the Wnt/ß-catenin inhibitor ICG-001 remarkably suppressed cell proliferation. Immunohistochemistry assay of tissue microarrays from patients with lung cancer indicated that both CBP and ß-catenin were highly expressed in tumor tissues and predicted poor prognosis in lung adenocarcinoma patients. CONCLUSIONS: Our study has provided new evidence for the role of ß-catenin in promoting the growth of lung cancer cells through cooperation with CBP, and suggested that dual targeting of ß-catenin and CBP could be a potential therapeutic strategy in lung cancer treatment.

CDC5L Promotes hTERT Expression and Colorectal Tumor Growth.

BACKGROUND/AIMS: Colorectal cancer (CRC) is the third leading cause of cancer-related death worldwide because the survival rate remains low. Cell division cycle 5-like (CDC5L) is highly expressed in some cancer cells, but the mechanism requires clarification. Human telomerase reverse transcriptase (hTERT) plays important roles in CRC. METHODS: This study aimed to identify a link between CDC5L and hTERT and to determine their effects on the signaling pathways, migration and prognosis of CRC cells. We first treated LoVo cells with biotin-labeled hTERT and identified CDC5L. Then, pulldown and ChIP assays were used to verify whether CDC5L was a promoter of hTERT. The roles of CDC5L and hTERT in cell growth and migration were studied using siRNA in vivo and in vitro. 130 human CRC specimens were analyzed using immunohistochemistry. Western blot and wound scratch analyses were used to determine the signaling pathway for CDC5L-mediated activation of CRC growth and migration. RESULTS: We identified CDC5L as a new hTERT promoter-binding protein. Clinically, CDC5L and hTERT expression levels were key factors in the prognosis of CRC patients. CDC5L knockdown inhibited tumor growth by down-regulating hTERT expression, and CDC5L was shown to be a transcriptional activator of hTERT in a luciferase reporter assay. CONCLUSION: Altogether, the above results demonstrated that CDC5L was positively correlated with hTERT as a key promoter of CRC cells. To some extent, our findings suggest that CDC5L may serve as a novel therapeutic target for human colorectal cancer.

S100A6 promotes cell proliferation in human nasopharyngeal carcinoma via the p38/MAPK signaling pathway.

An elevated level of S100A6 is associated with poor outcomes of many tumor types, but, how S100A6 contributes to nasopharyngeal carcinoma (NPC) progression remains unknown. Here, we investigated the expression and prognostic significance of S100A6 in NPC and explored the molecular mechanisms under-lying the role of S100A6 in NPC development. The results showed that S100A6 was markedly up-regulated in NPC tissues and cell lines compared to paired peritumoral normal tissues and a normal nasopharyngeal epithelial cell line, respectively. In tissues from 92 NPC patients, high S100A6 expression was associated with advanced N stage, locoregional failure and disease progression and was predictive of poor locoregional recurrence-free survival (LRRFS, P = 0.001) and progression-free survival (PFS, P = 0.001). Multivariate analysis showed that S100A6 is an independent prognostic factor for LRRFS and PFS. Silencing S100A6 using siRNA or shRNA significantly suppressed NPC cell proliferation, colony formation and p38/mitogen-activated protein kinase (MAPK) activity in vitro and inhibited tumor growth in a xenograft mouse model of NPC. In contrast, overexpressing S100A6 via plasmid transfection resulted in increased NPC cell proliferation and p38/MAPK activation. S100A6-induced proliferation was abolished by a p38 inhibitor. In summary, S100A6 may be a new prognostic marker of NPC and may promote NPC development via the activation of p38/MAPK signaling pathways. These findings suggest S100A6/p38/MAPK signaling as a potential therapeutic target for NPC. © 2016 Wiley Periodicals, Inc.

Aggressive Hydration With Lactated Ringer Solution in Prevention of Postendoscopic Retrograde Cholangiopancreatography Pancreatitis: A Meta-analysis of Randomized Controlled Trials.

BACKGROUND: Pancreatitis is the most common complication of endoscopic retrograde cholangiopancreatography (ERCP). The results of previous studies evaluating aggressive hydration with lactated Ringer solution for reducing the incidence of post-ERCP pancreatitis (PEP) are inconsistent. AIM: We performed a meta-analysis to determine whether aggressive hydration with lactated Ringer solution reduced PEP. METHODS: Randomized controlled trials (RCTs) comparing aggressive hydration with standard hydration with the same lactated Ringer solution for prophylaxis of PEP were searched in PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and CINAHL databases. ClinicalTrial.gov and International Standard Randomised Controlled Trial Number registry were also searched for unpublished studies. A meta-analysis was conducted in accordance with the Cochrane Handbook for Systemic Reviews of Intervention. RESULTS: A total of 7 RCTs with 1047 participants were included into this meta-analysis. Meta-analysis showed that aggressive hydration reduced the incidence of PEP as compared with standard hydration [odds ratio (OR), 0.47; 95% confidence interval (CI), 0.30-0.72; P=0.0006]. Aggressive hydration also reduced the incidence of post-ERCP hyperamylasemia as compared with standard hydration (OR, 0.38; 95% CI, 0.25-0.59; P<0.00001). No difference of adverse effects was found between aggressive hydration and standard hydration (OR, 0.48; 95% CI, 0.15-1.57; P=0.23). Sensitivity analyses showed that neither alternative effect measures nor statistical models regarding heterogeneity affected the conclusions of this meta-analysis. Sensitivity analyses also showed that omitting 1 study from analysis did not change the conclusion of this meta-analysis. CONCLUSIONS: On the basis of this meta-analysis of RCTs, aggressive hydration with lactated Ringer solution is an effective and safe therapy for prophylaxis of PEP.

Melatonin synergizes the chemotherapeutic effect of 5-fluorouracil in colon cancer by suppressing PI3K/AKT and NF-κB/iNOS signaling pathways.

5-Fluorouracil (5-FU) is one of the most commonly used chemotherapeutic agents in colon cancer treatment, but has a narrow therapeutic index limited by its toxicity. Melatonin exerts antitumor activity in various cancers, but it has never been combined with 5-FU as an anticolon cancer treatment to improve the chemotherapeutic effect of 5-FU. In this study, we assessed such combinational use in colon cancer and investigated whether melatonin could synergize the antitumor effect of 5-FU. We found that melatonin significantly enhanced the 5-FU-mediated inhibition of cell proliferation, colony formation, cell migration and invasion in colon cancer cells. We also found that melatonin synergized with 5-FU to promote the activation of the caspase/PARP-dependent apoptosis pathway and induce cell cycle arrest. Further mechanism study demonstrated that melatonin synergized the antitumor effect of 5-FU by targeting the PI3K/AKT and NF-κB/inducible nitric oxide synthase (iNOS) signaling. Melatonin in combination with 5-FU markedly suppressed the phosphorylation of PI3K, AKT, IKKα, IκBα, and p65 proteins, promoted the translocation of NF-κB p50/p65 from the nuclei to cytoplasm, abrogated their binding to the iNOS promoter, and thereby enhanced the inhibition of iNOS signaling. In addition, pretreatment with a PI3K- or iNOS-specific inhibitor synergized the antitumor effects of 5-FU and melatonin. Finally, we verified in a xenograft mouse model that melatonin and 5-FU exerted synergistic antitumor effect by inhibiting the AKT and iNOS signaling pathways. Collectively, our study demonstrated that melatonin synergized the chemotherapeutic effect of 5-FU in colon cancer through simultaneous suppression of multiple signaling pathways.

Bufalin Inhibits hTERT Expression and Colorectal Cancer Cell Growth by Targeting CPSF4.

BACKGROUND/AIMS: Bufalin can induce apoptosis in certain human cancer cell lines, but bufalin has not yet been thoroughly evaluated in colorectal cancer cells. Cleavage and polyadenylation specific factor 4 (CPSF4) and human telomerase reverse transcriptase (hTERT) play important roles in colorectal cancer growth. The aim of this study was to investigate the roles and interactions of bufalin, CPSF4 and hTERT and the effects of bufalin in human colorectal cancer. METHODS: We treated LoVo and SW620 cells with bufalin to investigate the effect of bufalin on proliferation, apoptosis and migration. We verified the relationship between CPSF4 and hTERT using pulldown assays, luciferase reporter assays and chromatin immunoprecipitation (ChIP) assays. RESULTS: Bufalin inhibited the proliferation and migration of and induced apoptosis in LoVo and SW620 cells. We identified CPSF4 as an hTERT promoter-binding protein in colorectal cancer cells. CONCLUSION: Our study identified bufalin as a potential small molecule inhibitor for cancer therapy.

Melatonin overcomes gemcitabine resistance in pancreatic ductal adenocarcinoma by abrogating nuclear factor-κB activation.

Constitutive activation and gemcitabine induction of nuclear factor-κB (NF-κB) contribute to the aggressive behavior and chemotherapeutic resistance of pancreatic ductal adenocarcinoma (PDAC). Thus, targeting the NF-κB pathway has proven an insurmountable challenge for PDAC therapy. In this study, we investigated whether the inhibition of NF-κB signaling pathway by melatonin might lead to tumor suppression and overcome gemcitabine resistance in pancreatic tumors. Our results showed that melatonin inhibited activities of NF-κB by suppressing IκBα phosphorylation and decreased the expression of NF-κB response genes in MiaPaCa-2, AsPc-1, Panc-28 cells and gemcitabine resistance MiaPaCa-2/GR cells. Moreover, melatonin not only inhibited cell proliferation and invasion in a receptor-independent manner, but also enhanced gemcitabine cytotoxicity at pharmacologic concentrations in these PDAC cells. In vivo, the mice treated with both agents experienced a larger reduction in tumor burden than the single drug-treated groups in an orthotopic xenograft mouse model. Taken together, these results indicate that melatonin inhibits proliferation and invasion of PDAC cells and overcomes gemcitabine resistance of pancreatic tumors through NF-κB inhibition. Our findings therefore provide novel preclinical knowledge about melatonin inhibition of NF-κB in PDAC and suggest that melatonin should be investigated clinically, alone or in combination with gemcitabine for PDAC treatment.

Down-regulation of prostate stem cell antigen (PSCA) by Slug promotes metastasis in nasopharyngeal carcinoma.

Distant metastasis and local recurrence are still the major causes for failure of treatment in patients with nasopharyngeal carcinoma (NPC), making it urgent to further elicit the molecular mechanisms of NPC metastasis. Using a gene microarray including transcription factors and known markers for cancer stem cells, prostate stem cell antigen (PSCA) was found to be significantly down-regulated in metastatic NPC in lymph node, compared to its primary tumour, and in NPC cell lines with high metastatic ability compared to those with low metastatic ability. NPC patients with low PSCA expression had a consistently poor metastasis-free survival (p = 0.003). Knockdown and overexpression of PSCA respectively enhanced and impaired the migration and invasion in vitro and the lung metastasis in vivo of NPC cells. Mechanistically, the enhancement of NPC metastasis by knocking down PSCA probably involved epithelial-mesenchymal transition (EMT), by up-regulating N-cadherin and ZEB1/2 and by activating RhoA. The down-regulation of PSCA in NPC cells resulted directly from the binding of Slug to the PSCA promoter. PSCA may be a potential diagnostic marker and therapeutic target for patients with NPC.

Multicenter randomized phase 2 clinical trial of a recombinant human endostatin adenovirus in patients with advanced head and neck carcinoma.

A randomized, open-label, phase 2, multicenter clinical trial was conducted to evaluate the efficacy and safety of the addition of a recombinant human endostatin adenovirus (E10A) to cisplatin and paclitaxel in patients with advanced head and neck squamous cell carcinoma or nasopharyngeal carcinoma. Patients with locally advanced or metastatic head and neck squamous cell carcinoma or nasopharyngeal carcinoma not suitable for operation or radiotherapy were randomly assigned to receive E10A plus chemotherapy every 3 weeks for a maximum of six cycles or to receive chemotherapy only. One hundred and thirty-six eligible patients were randomly assigned. The addition of E10A did not significantly improve the objective response rate (29.9 versus 39.7%, P = 0.154). However, patients who received endostatin had longer progression-free survival (7.03 versus 3.60 months, P = 0.006; hazard ratio: 0.55). The combination of E10A with chemotherapy benefited prior chemotherapy-treated patients and those who received three to four treatment cycles (6.50 versus 3.43 months, P = 0.003; 8.27 versus 4.27 months, P = 0.018; respectively). The overall disease control rate significantly increased from 80.6% in the control group to 92.6% in the test group (P = 0.034). Except for fever, no adverse events were associated with the E10A treatment. In summary, E10A plus chemotherapy is a safe and effective therapeutic approach in patients with advanced head and neck squamous cell carcinoma or nasopharyngeal carcinoma.