Securin Expression Research Articles

Clinical significance of securin expression in solid cancers: A PRISMA-compliant meta-analysis of published studies and bioinformatics analysis based on TCGA dataset.

Background:Numerous studies have investigated the clinical significance of securin expression in solid cancers; however, the results have been inconsistent. Hence, we performed a meta-analysis of published studies to assess the clinical value of securin expression in patients with solid cancers.Methods:The Chinese National Knowledge Infrastructure, Web of Science, PubMed, and EMDASE databases were searched for eligible studies (from inception up to April 2021). Bioinformatics analysis based on The Cancer Genome Atlas dataset was also performed to evaluate the prognostic value of securin expression.Results:A total of 25 articles with 26 studies were included in the meta-analysis. The results of the meta-analysis implied that high securin expression was positively correlated with unfavorable overall survival (OS) (hazard ratio = 1.52, 95% CI, 1.33–1.73; P < .001) and lymph node metastasis (odd ratio = 2.96, 95% CI, 2.26–3.86; P < .001). Consistently, our bioinformatics analysis showed that increased securin expression was associated with worse OS and shorter disease-free survival in cancer patients.Conclusion:Our study indicated that securin overexpression was positively associated with metastasis and inversely related to the prognosis of patients with solid cancers. However, additional high-quality studies should be conducted to validate these findings.

Impaired Cdc20 signaling promotes senescence in normal cells and apoptosis in non–small cell lung cancer cells

Cellular senescence is a form of irreversible growth arrest that cancer cells evade. The cell division cycle protein 20 homolog (Cdc20) is a positive regulator of cell division, but how its dysregulation may relate to senescence is unclear. Here, we find that Cdc20 mRNA and protein expression are downregulated in stress-induced premature senescent lung fibroblasts in a p53-dependent manner. Either Cdc20 downregulation or inhibition of anaphase-promoting complex/cyclosome (APC/C) is sufficient to induce premature senescence in lung fibroblasts, while APC/C activation inhibits stress-induced premature senescence. Mechanistically, we show both Cdc20 downregulation and APC/C inhibition induce premature senescence through glycogen synthase kinase (GSK)-3β–mediated phosphorylation and downregulation of securin expression. Interestingly, we determined Cdc20 expression is upregulated in human lung adenocarcinoma. We find that downregulation of Cdc20 in non–small cell lung cancer (NSCLC) cells is sufficient to inhibit cell proliferation and growth in soft agar and to promote apoptosis, but not senescence, in a manner dependent on downregulation of securin following GSK-3β-mediated securin phosphorylation. Similarly, we demonstrate securin expression is downregulated and cell viability is inhibited in NSCLC cells following inhibition of APC/C. Furthermore, we show chemotherapeutic drugs downregulate both Cdc20 and securin protein expression in NSCLC cells. Either Cdc20 downregulation by siRNA or APC/C inhibition sensitize, while securin overexpression inhibits, chemotherapeutic drug-induced NSCLC cell death. Together, our findings provide evidence that Cdc20/APC/C/securin-dependent signaling is a key regulator of cell survival, and its disruption promotes premature senescence in normal lung cells and induces apoptosis in lung cancer cells that have bypassed the senescence barrier.

Securin overexpression correlates with the activated Rb/E2F1 pathway and histone H3 epigenetic modifications in raw areca nut-induced carcinogenesis in mice

BackgroundRaw areca nut (RAN) consumption induces oral, esophageal and gastric cancers, which are significantly associated with the overexpression of pituitary tumor transforming gene 1/securin and chromosomal instability (CIN). An association of Securin/PTTG1 upregulation and gastric cancer in human was also demonstrated earlier. Since the molecular mechanism underlying securin upregulation remains unclear, this study intended to investigate the association of securin upregulation with the Rb-E2F1 circuit and epigenetic histone (H3) modification patterns both globally and in the promoter region of the securin gene.MethodsSix groups of mice were used, and in the treated group, each mouse consumed 1 mg of RAN extract with lime per day ad libitum in the drinking water for 60 days, after which the dose was increased by 1 mg every 60 days. Histopathological evaluation of stomach tissues was performed and securin expression was analysed by immunoblotting as well as by immunohistochemistry. ChIP-qPCR assays were performed to evaluate the recruitment of different histone modifications in the core promoter region of securin gene as well as its upstream and downstream regions.ResultsAll mice developed gastric cancer with securin overexpression after 300 days of feeding. Immunohistochemistry data revealed hyperphosphorylation of Rb and upregulation of E2F1 in the RAN-treated samples. Increased trimethylation of H3 lysine 4 and acetylation of H3 lysine 9 and 18 both globally and in the promoter region of the securin gene were observed by increasing the levels of lysine-N-methyltransferase 2A, lysine-acetyltransferase, EP-300 and PCAF after RAN treatment. ChIP-qPCR data revealed that the quantity of DNA fragments retrieved from the immunoprecipitated samples was maximum in the -83 to -192 region than further upstream and the downstream of the promoter for H3K4Me3, H3K9ac, H3K18ac and H3K9me3.ConclusionsRAN-mediated pRb-inactivation induced securin upregulation, a putative E2F1 target, by inducing misregulation in chromatin remodeling in its promoter region, which led to transcriptional activation and subsequent development of chromosomal instability. Therefore, present results have led to the hypothesis that RAN-induced changes in the epigenetic landscape, securin overexpression and subsequent elevation of chromosomal instability is probably byproducts of inactivation of the pRb pathway.

P250 - Long-term outcome of patients with luminal A breast cancer surrogate subtype according to chromosomal instability measured by securin expression

P250 - Long-term outcome of patients with luminal A breast cancer surrogate subtype according to chromosomal instability measured by securin expression

Abstract 3332: Targeting cancer stem cells in ovarian cancer

Abstract Ovarian cancer is a disease commonly complicated by the presence of ascites in the abdominal cavity which represents a major clinical problem. Currently, the treatment for ovarian cancer entails cytoreductive surgery followed by chemotherapy, mainly cisplatin or carboplatin combined with paclitaxel. Although this regimen is initially effective in a high percentage of cases, unfortunately within few months of initial treatment, tumor relapse occurs because of platinum-resistance. This is attributed mainly due to the presence of cancer stem cells (CSCs) present in ascites which are chemo-resistant and responsible for recurrence of cancer. In our preliminary studies, we show for the first time that withaferin A (WFA), a bioactive compound isolated from the plant Withania somnifera targets putative CSCs. Treatment of nude mice bearing orthotopic ovarian tumors with WFA resulted in a 70% to 80% reduction in tumor growth, complete inhibition of metastasis, and a significant elimination of the cells expressing CSCs markers - CD44, CD24, CD34, CD117, ALDH1 and Oct4 and down regulation of Notch1 and its downstream signaling genes (Hes1 and Hey1) reported to play crucial role for self-renewal and maintenance of CSCs. In addition, WFA also resulted in a significant inhibition of securin expression an “oncogene” important in ovarian tumorigenesis. In contrast, treatment of mice with CIS alone had the opposite effects, causing an increase in cells expressing CSC markers and Notch1 signaling pathway. However, combining of WFA with CIS showed enhanced effects on suppression of securin as well as elimination of CSCs. This may explain the development of platinum-resistance and recurrence of cancer in patients treated with first line chemotherapy. Based on this information, we hypothesize that a combination of WFA with CIS should target ovarian cancer cells as well as cancer stem cells by reducing securin and CSCs thereby reducing CIS resistance and recurrence of ovarian cancer. In our study, we used cells from ascites from patients with recurrent ovarian cancer and determine the effect of WFA alone and in combination with CIS on tumorigenic functions of ascites cells and CSCs from ascites in vitro and in vivo, and defined the molecular mechanisms associated with self-renewal, maintenance and recurrence of cancer in relation to expression of securin. Because the two agents act synergistically, this combination may minimize side effects as well as induction of cisplatin resistance and recurrence of cancer. In addition, this study will justify the initiation of phase I/phase II clinical trials to assess potential toxicity and efficacy of WFA/CIS combination in advanced/recurrent ovarian cancer patients. Citation Format: Sham S. Kakar, Mariusz Z. Ratajczak. Targeting cancer stem cells in ovarian cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3332.

Does securin expression have significance in prognostication of oral tongue cancer? A pilot study.

The proliferation marker, securin, is involved in the progression of many carcinomas. However, its expression in oral tongue squamous cell carcinoma (OTSCC) has not been previously studied. We examined securin expression by immunohistochemistry in OTSCC. A total of 93 cases treated for OTSCC were included in this study. Expression of securin in OTSCC was studied by immunohistochemistry of tissue microarrays (52 cases) and routine tumor sections (41 cases). Securin overexpression is significantly associated with higher tumor grade (P=0.03). Overexpression of securin was observed more frequently in advanced stages of OTSCC than in earlier stages but the difference was not statistically significant. These findings suggest that overexpression of securin in OTSCC may be important during progression of this cancer. No significant association was found between securin expression and the prognosis of OTSCC.

Prognostic implications of securin expression and sub-cellular localization in human breast cancer.

Securin belongs to a class of cell cycle regulators that prevent metaphase-to-anaphase transition until sister chromatid separation is complete. Evidence is accumulating that securin has a prognostic impact on a variety of malignancies but, thus far, the role and regulation of securin expression and its sub-cellular localization have not been systematically addressed in breast cancer. In total 470 breast cancer specimens with follow-up data for up to 22years were included. Immunohistochemical staining and immunofluorescence double-staining were performed for securin and its regulating proteins PTTG1IP, CDC20 and BUBR1. Prognostic associations were evaluated between the expression patterns of these proteins and established prognosticators of invasive breast cancer and patient survival. We found that a high fraction of securin expressing cancer cells predicted an unfavorable clinical outcome of the breast cancer patients (p < 0.001). Also in multivariate analyses, the fraction of securin expressing cancer cells served as an independent prognosticator of a poor survival (p < 0.0001). We also found that the sub-cellular localization of securin exhibited prognostic power, since cytoplasmic securin expression in the cancer cells appeared to be associated with aggressive breast cancer subtypes and high breast cancer-associated mortality rates (p = 0.003). Through immunofluorescence double-staining, we found that PTTG1IP, CDC20 and BUBR1 exhibited distinct patterns of co-expression with securin, suggesting a regulatory role in the metaphase-to-anaphase transition in human breast cancer cells. We also noted that a subgroup of triple-negative breast carcinomas exhibited deviant expression patterns for the proteins studied. Our data indicate that securin expression may serve as a strong and independent prognosticator of breast cancer outcome and that a cytoplasmic localization of the protein may provide additional prognostic information, particularly in the biologically and clinically challenging subgroup of triple-negative breast carcinomas. The sub-cellular localization of securin appears to reflect the expression of PTTG1IP, CDC20 and BUBR1, which may participate in the regulation of securin activity and, ultimately, in the survival of breast cancer patients.

Expression and clinical significance of the securin in colorectal cancer

Purpose: Securin is a regulatory protein, which plays a central role in chromosome stability and control of the metaphase-anaphase transition and anaphase onset. Securin blocks separase/extra spindle pole bodies homolog 1 function, preventing the proteolysis of the subsequent dissociation of the chromosome. Securin is expressed at low level in most tissues, but many patient suffering epithelial neoplasms are over-expressed. The aim our study was to evaluate whether securin affects tumorigenesis and prognosis in patients of colorectal cancer. Methods: To clarify the roles of securin in colorectal tumorigenesis, its expression was examined by immunohistochemistry on a tissue microarray with its comparison with clinicopathologic parameters and prognosis survivals of the colorectal carcinomas. Results: Securin was overexpressedin 272 (76.2%) of 357 colorectal carcinomas. Overexpression of securin was correlated with gender (P=0.060), pathologic T stage (P=0.006) and tumor node metastasis stage (P=0.002), but securin overexpression was not correlated with lymphovascular invasions. Securin overexpression was not correlated with 5-year survival rate by Kaplan-Miere survival model. Conclusion: Securin expression was correlated with T stage and TNM (tumor node and metastasis) stage in colorectal cancer. Our study showed a possible role for securin in colorectal tumorigenesis. These findings indicate that securin has a function of tumorigenesis with tumor enlargement, not of lymphovasculogenesis. Keywords: Carcinogenesis, Chromosomal instability, Colorectal neoplasms, Pituitary tumor-transforming gene protein

Cdc20 and securin overexpression predict short-term breast cancer survival.

Background:Cdc20 is an essential component of cell division and responsible for anaphase initiation regulated by securin degradation. Cdc20 function is strongly regulated by the spindle assembly checkpoint to ensure the timely separation of sister chromatids and integrity of the genome. We present the first results on Cdc20 in a large clinical breast cancer material.Methods:The study was based on 445 breast cancer patients with up to 20 years of follow-up (mean 10.0 years). DNA content was determined by image cytometry on cell imprints, and Cdc20 and securin immunohistochemistry on tissue microarrays of breast cancer tissue.Results:In our results, high Cdc20 and securin expression was associated with aneuploid DNA content. In prognostic analyses, high Cdc20 immunoexpression alone and in combination with high securin immunoexpression indicated aggressive course of disease and up to 6.8-fold (P<0.001) risk of breast cancer death. Particularly, high Cdc20 and securin immunoexpression identified a patient subgroup with extremely short, on average 2.4 years, breast cancer survival and triple-negative breast cancer (TNBC) subtype.Conclusions:We report for the first time the association of high Cdc20 and securin immunoexpression with extremely poor outcome of breast cancer patients. Our experience indicates that Cdc20 and securin are promising candidates for clinical applications in breast cancer prognostication, especially in the challenging prognostic decisions of TNBC.

Downregulation of Securin by the variant RNF213 R4810K (rs112735431, G>A) reduces angiogenic activity of induced pluripotent stem cell-derived vascular endothelial cells from moyamoya patients

Moyamoya disease (MMD) is a cerebrovascular disease characterized by occlusive lesions in the circle of Willis. The RNF213 R4810K polymorphism increases susceptibility to MMD. Induced pluripotent stem cells (iPSCs) were established from unaffected fibroblast donors with wild-type RNF213 alleles, and from carriers/patients with one or two RNF213 R4810K alleles. Angiogenic activities of iPSC-derived vascular endothelial cells (iPSECs) from patients and carriers were lower (49.0±19.4%) than from wild-type subjects (p<0.01). Gene expression profiles in iPSECs showed that Securin was down-regulated (p<0.01) in carriers and patients. Overexpression of RNF213 R4810K downregulated Securin, inhibited angiogenic activity (36.0±16.9%) and proliferation of humanumbilical vein endothelial cells (HUVECs) while overexpression of RNF213 wild type did not. Securin expression was downregulated using RNA interference techniques, which reduced the level of tube formation in iPSECs and HUVECs without inhibition of proliferation. RNF213 R4810K reduced angiogenic activities of iPSECs from patients with MMD, suggesting that it is a promising in vitro model for MMD.

Low cdc27 and high securin expression predict short survival for breast cancer patients

Cell cycle regulators cdc27 and securin participate in control of the mitotic checkpoint and survey the mitotic spindle to maintain chromosomal integrity. This is achieved by their functions in metaphase-anaphase transition, DNA damage repair, enhancement of mitotic arrest and apoptosis. We report on the roles of cdc27 and securin in aneuploidy and prognosis of breast cancer. The study comprises 429 breast cancer patients with up to 22years of follow-up. DNA content was determined by image cytometry, and immunopositivity for cdc27 and securin was based on tissue microarrays. An inverse association between cdc27 and securin expression was observed in both image cytometric and immunohistochemical analyses. Low cdc27 and high securin expression identified patients with significant difference in disease outcome. Cdc27 and securin immunoexpression identified patients at risk of early cancer death within five years from diagnosis. In multivariate analysis, the combination of cdc27 and securin immunohistochemistry was the strongest predictor of cancer death after lymph node status. We demonstrate, for the first time in human breast cancer, the prognostic value of cdc27 and securin immunohistochemistry. Cdc27 and securin appear promising biomarkers for applications in predicting disease progression, prognostication of individual patients and potential in anti-mitotic drug development.

Evidence of securin-mediated resistance to gefitinib-induced apoptosis in human cancer cells

Gefitinib, a tyrosine kinase inhibitor of the epidermal growth factor receptor (EGFR), has been used to treat numerous cancers; however, evidence has shown that cancer cells can become resistant to gefitinib during therapy. Here, we report a human proto-oncogene, securin, which displays resistance to death in cancer cells. Gefitinib treatment decreases securin levels at the protein level by inducing protein instability but did not affect on the securin gene expression. Treatment with gefitinib induced cytotoxicity in various human cancer cell types, including RKO (colon cancer), A549 (lung cancer), BFTC905 (bladder cancer), MCF7 (breast cancer) and A375 (skin cancer). BFTC905 and A549 cells expressed relatively high levels of the phosphorylated and total EGFR proteins; however, A375, MCF7 and RKO cells did not markedly express these proteins. Moreover, following treatment with gefitinib, the securin-wild type cancer cells were more resistant to apoptotic induction than the securin-null cancer cells. Surprisingly, both the securin-wild type and securin-null cancer cells expressed the EGFR protein at similar levels. Treatment with gefitinib induced mitochondrial dysfunction, cytochrome c release, caspase-3 activation and poly (ADP-ribose) polymerase protein cleavage, indicating that apoptosis occurred in these cancer cells. The transfection of a GPF–securin expression vector increased both the proliferation rates and resistance to gefitinib-induced death in these cancer cells. Taken together, these findings demonstrate that the presence of securin promotes resistance to gefitinib-induced apoptosis via an EGFR-independent pathway in human cancer cells.

Strain Specific Spontaneous Activation During Mouse Oocyte Maturation.

Objective To examine whether spontaneous oocyte activation is determined by genetic differences and interacts with culture environment. Design Experimental study. Setting Temple University School of Medicine. Animal(s) C57BL/6, DBA/2, C3H/HeJ, and A/J strains, along with reciprocal F1 hybrid female mice (5–6 weeks). Intervention(s) Immature oocytes from different mouse strains collected and cultured in different maturation conditions, including different serum, serum replacement, bovine serum albumin (BSA), and follicle-stimulation hormone (FSH). Main Outcome Measure(s) The emission of first polar body, pronucleus formation, meiotic arrest, spontaneous activation, and expression of maturation regulators. Result(s) Oocytes from C57BL/6 mice display a high rate of delayed first meiotic division and spontaneous activation after the first meiotic division with in vitro maturation (IVM), and the second meiotic division with in vivo maturation (VVM) after superovulation. Spontaneous activation with IVM is sensitive to culture environment. Oocytes that spontaneously activated during the first meiotic division with IVM have unusual replicated sister chromatid pairs with slight connections at centromeres at first mitosis, whereas oocytes that activated in vivo display haploidization from the second meiotic division. Spontaneous activation is also seen in F1 hybrid oocytes, indicating a dominant trait from C57BL/6. Delayed meiosis was associated with reduced cyclin B and securin expression. Conclusion(s) Both mouse strain and culture environment have a statistically significant effect on the incidence of meiotic defects and spontaneous activation. Reduced expression of meiotic regulators may underlie this effect.

Securin predicts aneuploidy and survival in breast cancer

Securin is known to participate in maintaining chromosomal integrity during the cell cycle through regulation of metaphase-anaphase transition, DNA damage repair, and apoptosis. The aim of this study was to investigate the role of securin in aneuploidy and prognosis in human breast cancer. The study was based on 603 breast cancer patients with up to 20 years of follow-up. DNA content was determined by image cytometry on cell imprints, and securin immunohistochemistry was performed on tissue microarrays of breast cancer tissue. We show, for the first time in human breast cancer, that high-level securin expression predicts abnormal DNA content, with up to 9.8-fold odds for aneuploid DNA content (P = 0.0007). Securin also shows strong independent prognostic value for disease-specific survival, with a significant difference in survival time between patients with low-level and high-level securin expression. The main result of the present study is the association of aneuploidy and securin expression. According to our results, securin immunohistochemistry is also a potential new prognosticator for treatment decisions concerning breast cancer patients.

Securin identifies a subgroup of patients with poor outcome in rectal cancer treated with long-course (chemo)radiotherapy

Background. Securin is an oncogene with functions in cell proliferation, tumour initiation and progression. Its prognostic value in rectal cancer is somewhat unknown. Accordingly, we studied securin expression together with Ki-67 in rectal cancer in relation to preoperative (chemo)radiotherapy (RT) and disease outcome. Material and methods. Biopsies (n = 65 for securin; n = 57 for Ki-67) and operative specimens (n = 207) from 211 patients treated with short-course RT (n = 87), long-course RT (n = 54) or surgery only (n = 70) were studied with immunohistochemistry (IHC) for securin and Ki-67 expression. In the long-course RT group, 45 patients received chemotherapy (5-fluorouracil or capecitabine) concomitantly with RT. The results of IHC were related to clinicopathological variables, disease outcome and tumour regression grade (TRG) after long-course RT. Results. Both markers showed significant reduction after RT (p < 0.001). No differences in expression was seen in the long-course RT group between the patients with or without concomitant chemotherapy (p = 0.23 for securin; p = 0.31 for Ki-67). Low Ki-67 expression, but not that of securin, in operative specimens was significantly related to excellent TRG (p = 0.02 for Ki-67; p = 0.21 for securin). In univariate survival analysis, excellent TRG predicted longer disease-specific survival (DSS; p = 0.03). In multivariate Cox analysis, high securin expression after long-course (chemo)RT was an independent predictor of shorter DSS (p = 0.036) together with patient age (p = 0.043) and disease recurrence (local or distant; p = 0.009), whereas no similar appearance was seen in other treatment groups. Conclusion. Securin expression in rectal cancer is significantly reduced after RT. High securin expression and poor TRG after long-course (chemo)RT are indicators of unfavourable disease outcome.

Overexpression of Securin in Human Transitional Cell Carcinoma Specimens

Objective Securin, the product of PTTG (pituitary tumor transforming gene), is overexpressed in several tumors, and plays important roles in cancer progression and invasion. In our previous report, securin expression was observed in transitional cell carcinoma (TCC; the most common pathological pattern of bladder cancer) cell lines, including BFTC905, T24, and TSGH8301. However, the existence of securin in human bladder cancer specimens has not been established. Materials and Methods Commercial bladder cancer tissue arrays (BL208 & BLC661) were used. Slides of paraffin-fixed human bladder tissues included all grades of TCC (18, 22 and 29 tissue samples for grades I, II, and III, respectively), 21 superficial and 41 invasive TCC specimens, and 11 normal urothelial tissue samples. The intensities of securin immunostaining were graded as background, mild, and strong (scored as 0, 1, and 2, respectively), and scores from the nucleus and cytosol were analyzed separately. Results We have demonstrated, for the first time, the expression of securin in bladder tissues. Securin was overexpressed in the cytosol and nucleus of all TCC samples compared to normal urothelium, but only cytosolic localization revealed statistical significance. There were no differences in securin immunoreactivity among the different grades of TCC. Significant over-expression of cytosolic but not nuclear securin was found in both superficial and invasive TCC samples compared to normal urothelium. No difference in immunoreactive staining for nuclear and cytosolic securin between superficial and invasive TCC was noted. Conclusion Significant enhanced expression of cytosolic securin protein was found in human bladder cancer specimens, suggesting that the level of tissue securin may be a potential biomarker for the diagnosis of bladder cancer. Studies that investigate the relationship between securin expression and the outcomes of bladder cancer patients could be conducted in the future.

Change of structural maintenance of chromosome (SMC)1, SMC3, Separase and Securin expression in BEAS-2B malignant transformation cell induced by coal tar pitch smoke extracts

to study the role of structural maintenance of chromosome (SMC)1, SMC3, Separase and Securin in tumorgenesis that contact with coal tar pitch. the BEAS-2B cells was induced by coal tar pitch smoke extracts to form malignant transformation cell model in vitro. The gene expression levels of mRNA were assessed by real-time quantitative RT-PCR, and the protein expression variation were determined by cell culture overslip of immunohistochemical methods. in malignant transformation cells, the mRNA and the protein expression level of SMC1 gene was not statistically significantly different compared with the BEAS-2B group and DMSO group (P > 0.05); SMC3 and Separase was increased and Securin was decreased (P < 0.05), while the difference between other two control groups was not significant (P > 0.05). the up expression level of SMC3 and Separase and the down expression level of Securin are involved in the process that evolves into malignant transformation in bronchial epithelial cells BEAS-2B induced by coal tar pitch smoke extracts.

TrkB antibody elicits cytotoxicity and suppresses migration/invasion of transitional cell carcinoma cells

BDNF (brain-derived neurotrophic factor) and its receptor TrkB (tropomyosin receptor kinase B) play important roles in the progression of cancer, including transitional cell carcinoma (TCC) cells reported in our previous investigation. In this study, we used a specific TrkB antibody (Ab) to evaluate its effects on survival, proliferation and migration/invasion in three TCC cell lines (BFTC905, T24 and TSGH8301) in vitro. The TrkB Ab at 1 and 3 microg/ml, but not the TrkA or TrkC Abs, significantly elicited cytotoxicity in TCC cells. The TrkB Ab at 3 microg/ml also induced apoptosis of TCC cells, which may result from up-regulation of phospho-p38 plus down-regulation of survivin and securin expression. The TrkB Ab at 0.5 microg/ml, which did not show cytotoxicity, suppressed migration of TCC cells and invasion of BFTC905 cells, possibly mediated through increased E-cadherin, decreased BDNF-stimulated phospho-PLCgamma1 and reduced MMP-9 activity. These results indicate that TrkB blockade may be a new strategy for TCC therapy.

Lestaurtinib is Cytotoxic to Oxaliplatin-resistant Transitional Cell Carcinoma Cell Line T24 In Vitro

Objective Patients with bladder cancer have responded poorly to oxaliplatin therapy in clinical trials. Blockade of receptor tyrosine kinases is considered a good strategy in cancer therapy. Our previous studies have demonstrated the crucial roles of brain-derived neurotrophic factor and its receptor tropomyosin receptor kinase B (TrkB) in transitional cell carcinoma (TCC). The aim of this study was to examine the cytotoxic effects of lestaurtinib, a new pan-Trk inhibitor, and oxaliplatin on bladder cancer cell lines. Materials and Methods BFTC905 and T24 TCC cell lines were used for investigation in vitro. The effects of oxaliplatin and/or lestaurtinib on cell viability, apoptosis, and expression of survivin and securin were assessed. MTT assay was used for cytotoxic evaluation. DNA fragments were detected in both the culture medium and cytoplasm to differentiate the types of cell death (apoptosis vs. necrosis). Western blots were used to analyze the expression of survivin and securin after oxaliplatin and/or lestaurtinib treatment. Results Oxaliplatin at 3 μg/mL elicited cytotoxicity on BFTC905 but not T24 cells 48 hours after treatment. The addition of 1 or 3 μM lestaurtinib to oxaliplatin did not exert additive cytotoxic effects on BFTC905 cells. Although oxaliplatin at 3 μg/mL had no effect on T24 cells, the addition of 1 or 3 μM lestaurtinib demonstrated concentration-dependent inhibitory effects. Apoptosis of T24 cells was observed after treatment with lestaurtinib alone and lestaurtinib plus oxaliplatin. Furthermore, in T24 cells, the expression of survivin was inhibited by a combination of lestaurtinib and oxaliplatin, while securin expression was inhibited by lestaurtinib alone and lestaurtinib with oxaliplatin. Conclusion Lestaurtinib may be a potential new drug for the targeted therapy of oxaliplatin-resistant TCC. Further in vivo studies are needed.

Opposite expression of securin and γ‐H2AX regulates baicalein‐induced cancer cell death

Securin and γ-H2AX have been shown to regulate cell survival and genomic stability. However, it is still unknown how the expression and regulation of these proteins is altered following treatment with baicalein, a natural flavonoid extracted from the Scutellaria baicalensis root. In the present study, we investigate the possible roles of securin and γ-H2AX in baicalein-induced cancer cell death. Baicalein reduced cell viability in a variety of human cancer cell lines, including bladder, cervical, colon, and lung cancer cells. Interestingly, baicalein treatment (40-80 µM for 24 h) markedly inhibited securin expression, while the levels of γ-H2AX were elevated. Abnormal spindle formation and chromosomal segregation were induced by baicalein. Furthermore, wild type HCT116 cancer cells had a higher incidence of cytotoxicity and apoptosis than securin-null HCT116 cells following treatment with baicalein. In contrast, baicalein increased the levels of γ-H2AX to a similar extent in both cell types. Transfection with H2AX siRNA further increased baicalein-induced cell death. Additionally, blockade of the AKT pathway by treatment with wortmannin or AKT shRNA lowered the levels of γ-H2AX and enhanced cytotoxicity in baicalein-treated cells. Taken together, our findings suggest that the opposing effects of baicalein on securin and γ-H2AX levels may be involved in the regulation of cell viability and genomic stability by this compound.