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Background: More than twenty years after its discovery, the role of the importin beta superfamily member Ran GTP-binding protein (RanBP) 17 is still ill defined. Previously, we observed notable RanBP17 RNA expression levels in head and neck squamous cell carcinoma (HNSCC) cell lines with disruptive TP53 mutations.Methods: We deployed HNSCC cell lines as well as cell lines from other tumor entities such as HCT116, MDA-MB-231 and H460, which were derived from colon, breast and lung cancers respectively. RNAi was used to evaluate the effect of RanBP17 on cell proliferation. FACS analysis was used for cell sorting according to their respective cell cycle phase and for BrdU assays. Immunocytochemistry was deployed for colocalization studies of RanBP17 with Nucleolin and SC35 (nuclear speckles) domains. TCGA analysis was performed for prognostic assessment and correlation analysis of RanBP17 in HNSCC patients.Results: RNAi knockdown of RanBP17, significantly reduced cell proliferation in HNSCC cell lines. This effect was also seen in the HNSCC unrelated cell lines HCT116 and MDA-MB-231. Similarly, inhibiting cell proliferation with cisplatin reduced RanBP17 in keratinocytes but lead to induction in tumor cell lines. A similar observation was made in tumor cell lines after treatment with the EGFR kinase inhibitor AG1478. In addition to previous reports, showing colocalization of RanBP17 with SC35 domains, we observed colocalization of RanBP17 to nuclear bodies that are distinct from nucleoli and SC35 domains. Interestingly, for HPV positive but not HPV negative HNSCC, TCGA data base analysis revealed a strong positive correlation of RanBP17 RNA with patient survival and CDKN2A.Conclusions: Our data point to a role of RanBP17 in proliferation of HNSCC and other epithelial cells. Furthermore, RanBP17 could potentially serve as a novel prognostic marker for HNSCC patients. However, we noted a major discrepancy between RanBP17 RNA and protein expression levels with the used antibodies. These observations could be explained by the presence of additional RanBP17 splice isoforms and more so of non-coding circular RanBP17 RNA species. These aspects need to be addressed in more detail by future studies. [ABSTRACT FROM AUTHOR]

Background: High expression levels of Inhibitors of Apoptosis Proteins (IAPs) have been correlated with poor cancer prognosis and block the cell death pathway by interfering with caspase activation. SMAC-mimetics are small-molecule inhibitors of IAPs that mimic the endogenous SMAC and promote the induction of cell death by neutralizing IAPs.Methods: In this study, anti-tumour activity of new SMAC-mimetics Birinapant and AT-406 is evaluated against colorectal adenocarcinoma cells and IAP cross-talk with either oncogenic BRAF or BCL-2, or with the TRAIL are further exploited towards rational combined protocols.Results: It is shown that pre-treatment of SMAC-mimetics followed by their combined treatment with BRAF inhibitors can decrease cell viability, migration and can very efficiently sensitize colorectal tumour cells to apoptosis. Moreover, co-treatment of TRAIL with SMAC-mimetics can efficiently sensitize resistant tumour cells to apoptosis synergistically, as shown by median effect analysis. Finally, Birinapant and AT-406 can synergise with BCL-2 inhibitor ABT-199 to reduce viability of adenocarcinoma cells with high BCL-2 expression.Conclusions: Proposed synergistic rational anticancer combined protocols of IAP antagonists Birinapant and AT-406 in 2D and 3D cultures can be later further exploited in vivo, from precision tumour biology to precision medical oncology. [ABSTRACT FROM AUTHOR]

Background: Class III ß-tubulin, Sox2, and Survivin play important roles in tumor survival and proliferation. However, the association of these three factors with clinicopathological characteristics, chemoresistance, and survival in patients with ovarian cancer remains controversial. Methods: We investigated the predictive value and correlation among the expression levels of Class III ß-tubulin, Sox2, and Survivin in 110 patients with stage III ovarian epithelial cancer, including 58 patients who received taxane-based chemotherapy and 52 patients who received non-taxane-based chemotherapy. Expression of these three factors was immunohistochemically examined in 110 ovarian tumor tissues obtained from patients before chemotherapy. Results: The positive expression rates for Class III ß-tubulin, Sox2, and Survivin in ovarian tumor tissues were 59.09 %, 61.82 % and 52.73 %, respectively. The expression of nuclear Survivin and Class III ß-tubulin was consistent with that of Sox2 (p = 0.005 and 0.020, respectively). Positive expression of Class III ß-tubulin, Sox2, and nuclear Survivin was significantly associated with chemoresistance to taxane-based chemotherapy (p = 0.006, 0.007, and 0.009, respectively), but not to non-taxane-based chemotherapy. Additionally, overexpression of Class III ß-tubulin, Sox2, and nuclear Survivin predicted poor progression-free survival in patients receiving taxane-based chemotherapy (p = 0.032, 0.005, and 0.004, respectively). Conclusions: These findings suggest that overexpression of Class III ß-tubulin, Sox2, and nuclear Survivin might be predictive of taxane resistance and poor progression-free survival in patients with stage III ovarian epithelial cancer. Expression of these three factors may show positive correlations in these patients. [ABSTRACT FROM AUTHOR]

Background: Class III β-tubulin, Sox2, and Survivin play important roles in tumor survival and proliferation. However, the association of these three factors with clinicopathological characteristics, chemoresistance, and survival in patients with ovarian cancer remains controversial. Methods: We investigated the predictive value and correlation among the expression levels of Class III β-tubulin, Sox2, and Survivin in 110 patients with stage III ovarian epithelial cancer, including 58 patients who received taxane-based chemotherapy and 52 patients who received non-taxane-based chemotherapy. Expression of these three factors was immunohistochemically examined in 110 ovarian tumor tissues obtained from patients before chemotherapy. Results: The positive expression rates for Class III β-tubulin, Sox2, and Survivin in ovarian tumor tissues were 59.09 %, 61.82 % and 52.73 %, respectively. The expression of nuclear Survivin and Class III β-tubulin was consistent with that of Sox2 (p = 0.005 and 0.020, respectively). Positive expression of Class III β-tubulin, Sox2, and nuclear Survivin was significantly associated with chemoresistance to taxane-based chemotherapy (p = 0.006, 0.007, and 0.009, respectively), but not to non-taxane-based chemotherapy. Additionally, overexpression of Class III β-tubulin, Sox2, and nuclear Survivin predicted poor progression-free survival in patients receiving taxane-based chemotherapy (p = 0.032, 0.005, and 0.004, respectively). Conclusions: These findings suggest that overexpression of Class III β-tubulin, Sox2, and nuclear Survivin might be predictive of taxane resistance and poor progression-free survival in patients with stage III ovarian epithelial cancer. Expression of these three factors may show positive correlations in these patients. [ABSTRACT FROM AUTHOR]

Background: Pancreatic ductal adenocarcinoma (PDAC) is highly resistant to conventional chemotherapy, in part due to the overexpression of inhibitors of apoptosis proteins (IAPs). Smac is an endogenous IAP-antagonist, which renders synthetic Smac mimetics attractive anticancer agents. We evaluated the benefits of combining a Smac mimetic, JP1201 (JP), with conventional chemotherapy agents used for PDAC management. Methods: Cell viability assays and protein expression analysis were performed using WST-1 reagent and Western blotting, respectively. Apoptosis was detected by annexin V/propidium iodide staining. In vivo tumor growth and survival studies were performed in murine PDAC xenografts. Results: JP and gemcitabine (Gem) inhibited PDAC cell proliferation with additive effects in combination. The percentage of early apoptotic cells in controls, JP, Gem and JP + Gem was 17%, 26%, 26% and 38%, respectively. JP-induced apoptosis was accompanied by PARP-1 cleavage. Similar additive anti-proliferative effects were seen for combinations of JP with doxorubicin (Dox) and docetaxel (DT). The JP + Gem combination caused a 30% decrease in tumor size in vivo compared to controls. Median animal survival was improved significantly in mice treated with JP + Gem (38 d) compared to controls (22 d), JP (28 d) or Gem (32 d) (p = 0.01). Animal survival was also improved with JP + DT treatment (32 d) compared to controls (16 d), JP (21 d) or DT alone (27 d). Conclusions: These results warrant further exploration of strategies that promote chemotherapy-induced apoptosis of tumors and highlight the potential of Smac mimetics in clinical PDAC therapy. [ABSTRACT FROM AUTHOR]

Background: It has been shown that IAPs, in particular XIAP, survivin and c-IAP1, are overexpressed in several malignancies. In the present study we investigate the expression of c-IAP1, c-IAP2, XIAP and survivin and its isoforms in cervical cancer. Methods: We used semiquantitative RT-PCR assays to analyze 41 cancer and 6 normal tissues. The study included 8 stage I cases; 16 stage II; 17 stageIII; and a control group of 6 samples of normal cervical squamous epithelial tissue. Results: c-IAP2 and XIAP mRNA levels were similar among the samples, cervical tumors had lower c-IAP1 mRNA levels. Unexpectedly, a clear positive association was found between low levels of XIAP and disease relapse. A log-rank test showed a significant inverse association (p = 0.02) between XIAP expression and tumor aggressiveness, as indicated by disease relapse rates. There were no statistically significant differences in the presence or expression levels of c-IAP1 and c-IAP2 among any of the clinical variables studied. Survivin and its isoforms were undetectable in normal cervical tissues, in contrast with the clear upregulation observed in cancer samples. We found no association between survivin expression and age, clinical stage, histology or menopausal state. Nevertheless, we found that adenocarcinoma tumors expressed higher levels of survivin 2B and DeltaEx3 (p = 0.001 and p = 0.04 respectively, by Kruskal-Wallis). A multivariate Cox's partial likelihood-based analysis showed that only FIGO stage was an independent predictor of outcome. Conclusion: There are no differences in the expression of c-IAP2 and XIAP between normal vs. cancer samples, but XIAP expression correlate in cervical cancer with relapse of this disease in the patients. Otherwise, c-IAP1 was downregulated in the cervical cancer samples. The expression of survivin was upregulated in the patients with cervical cancer. We have found that adenocarcinoma presented higher levels of survivin isoforms 2B and DeltaEx3. [ABSTRACT FROM AUTHOR]