• Journal of Life Science
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• v.26 no.7
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• pp.826-834
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• 2016

The present investigation was undertaken to examine the effectiveness of the combination treatment of an Hsp90 inhibitor and a SIRT1 inhibitor on suppressing the growth of chemo-resistant human cancer cells. We showed that inhibition of SIRT1 effectively potentiated the cytotoxicity of 17-allylamino-17-demethoxygeldanamycin (17-AAG) and reversed Hsp90 inhibitor resistance in multidrug-resistant (MDR) human ovarian HeyA8-MDR cells. Amurensin G, a potent natural SIRT1 inhibitor, enhanced Hsp90 inhibitor-mediated abrogation of the Hsp90 chaperone function and accelerated degradation of mutated p53 (mut p53), an Hsp90 client protein, by up-regulation of ubiquitin ligase CHIP. Knock-down of CHIP significantly attenuated amurensin G-induced mut p53 degradation. Down-regulation of mut p53 reduced the expression of heat shock factor1 (HSF1)/heat shock proteins (Hsps), a major cause of Hsp90 inhibitor resistance, which led to sensitization of the MDR cells to the Hsp90 inhibitor by the SIRT1 inhibitor. Amurensin G potentiated cytotoxicity of the Hsp90 inhibitor in HeyA8-MDR cells through suppression of 17-AAG-induced Hsp70 and Hsp27 induction via down-regulation of mut p53/HSF1, and it caused activation of PARP and inhibition of Bcl-2. Our data suggests that SIRT1 inhibitors could be used to sensitize MDR cells to Hsp90 inhibitors, possibly through suppression of the mut p53/HSF1-dependent pathway, and a novel mut p53-directed action of SIRT1 inhibition could effectively prevent mut p53 accumulation in MDR cells.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.1
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• pp.75-84
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• 2014

Aberrant DNA methylation of tumor suppressor genes has been reported in all major types of leukemia with potential involvement in the inactivation of regulatory cell cycle and apoptosis genes. However, most of the previous reports did not show the extent of concurrent methylation of multiple genes in the four leukemia types. Here, we analyzed six key genes (p14, p15, p16, p53, DAPK and TMS1) for DNA methylation using methylation specific PCR to analyze peripheral blood of 78 leukemia patients (24 CML, 25 CLL, 12 AML, and 17 ALL) and 24 healthy volunteers. In CML, methylation was detected for p15 (11%), p16 (9%), p53 (23%) and DAPK (23%), in CLL, p14 (25%), p15 (19%), p16 (12%), p53 (17%) and DAPK (36%), in AML, p14 (8%), p15 (45%), p53 (9%) and DAPK (17%) and in ALL, p15 (14%), p16 (8%), and p53 (8%). This study highlighted an essential role of DAPK methylation in chronic leukemia in contrast to p15 methylation in the acute cases, whereas TMS1 hypermethylation was absent in all cases. Furthermore, hypermethylation of multiple genes per patient was observed, with obvious selectiveness in the 9p21 chromosomal region genes (p14, p15 and p16). Interestingly, methylation of p15 increased the risk of methylation in p53, and vice versa, by five folds (p=0.03) indicating possible synergistic epigenetic disruption of different phases of the cell cycle or between the cell cycle and apoptosis. The investigation of multiple relationships between methylated genes might shed light on tumor specific inactivation of the cell cycle and apoptotic pathways.

• Tuberculosis and Respiratory Diseases
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• v.46 no.4
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• pp.523-532
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• 1999

Background: With the development of the molecular biological methods, studies of the early diagnosis of lung cancer and the detection in the preneoplastic state by using genetic probes in the high risk groups are widely investigated. In lung cancer, squamous cell carcinoma is considered to progress from the normal bronchial mucosa to the preneoplastic state, and finally to the invasive carcinoma. In this study, we investigated the expression of p53 and c-erbB2 in the normal bronchi and the cancer tissues in patients with squamous cell lung cancer to evaluate the possibility of using these immunohistochemical markers as the diagnostic and prognostic parameters of patients with squamous cell lung cancer. Method: The normal and cancerous bronchial tissues of 25 patients with squamous cell carcinoma of the lung, surgically resected from May 1995 to November 1996, were immunohistochemically stained with the monoclonal antibodies to p53(DAKO-p53) and c-erbB2(phamingen 15821A) respectively. We compared the expression status of these markers between the normal bronchial mucosa and the tumor tissue, and also investigated the relationship between the expression status of these markers in tumor tissues and the pathological stage, and the survival time. Results: The pathological stage was as follows; stage I, II were found in 5 patients respectively, stage IIIA was in 8 patients, stage IIIB was in 4 patients, and stage IV was in 3 patients. The expression rate of p53 in the squamous cell lung cancer was 48%, and it was not expressed in the normal bronchial mucosa. The expression status was increased as the pathological stage advanced(p=0.0091 by test of trend). But there were no relationship between the expression of p53 and the median survival time. C-erbB2 did not yield a significantly meaningful result. Conclusion: p53 was not found in the normal bronchial mucosa, but it was expressed in 48% of the tumor tissue. And the expression rate increased as the pathological stage advanced. So it would be helpful to apply the immunochistochemical stain with p53 in the bronchial biopsy specimen in the early diagnosis trial or staging of squamous cell lung cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.8
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• pp.3415-3418
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• 2014

Background: AKAP12 inhibits oncogenic proliferation, invasion, chemotaxis and neovascularization. Bcl-2 and p53 are two important apoptotic markers that play roles in apoptotic processes. It has been found that AKAP12 blocks the cell cycle and induces apoptosis in fibrosarcoma cells. In our study we assessed the relationship of AKAP12 with apoptotic markers, Bcl-2 and p53. Materials and Methods: Our study included 45 cases that were histopathologically diagnosed with colorectal carcinoma from the tissue samples acquired by surgical resection. AKAP 12, Bcl-2, and p53 expression was examined by immunohistochemistry. Results: A total of 45 colorectal adenocarcinoma patients - 17 (37.8%) females and 28 (62.2%) males - were included in this study. AKAP12 expression was found to be negative in 8 patients (17.8%), and positive in 37 patients (82.2%). Bcl-2 was found positive in 6 patients (13.3%) and p53 in 29 patients (55.6%). AKAP12 expression had no significant relation with Bcl-2 and p53 expression (p:0.939, p:0.079, respectively). Conclusions: Although various studies have pointed to apoptotic activity of AKAP12, the literature is limited regarding relations with p53 or Bcl-2 expression. In the present study, we found no relation in colorectal carcinomas.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.10
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• pp.4169-4172
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• 2015

Background: Oral carcinoma (OC) remains as one of the most difficult malignancies to cure. Hesa-A is an Iranian herbal-marine compound that has shown promising anti-tumor properties on various human cancer cells, although the mechanisms of action remain to be addressed. This study was conducted to evaluate the effect of two doses of Hesa-A on mRNA expression of p53 as a main prognosticator of OC. Materials and Methods: 60 rats were randomly divided into 5 groups of 12 animals each. Rats in carcinoma groups received 0, 250 and 500 mg/kg body weight of Hesa-A three times a day. The two other groups considered as treated and untreated healthy groups. At the end of experiment, animals were sacrificed and tongue tissues subjected to H and E staining and real time PCR. Results: Our results indicated that compared to healthy group, p53 over expressed ~ 40% in untreated carcinoma group. After treatment with 250mg/kg and 500mg/kg body weights of Hesa-A, p53 level dropped by 53.4% and 13.6 %, respectively, compared to untreated carcinoma group (p<0.05, p<0.0001). Moreover, there was a significant relation between p53 mRNA content and observed pathological changes in studied groups (p<0.05). Conclusions: These data provide insights into the mechanism(s) by which Hesa-A improves clinical outcome of oral carcinoma by modulation of p53 expression.

• BMB Reports
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• v.41 no.10
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• pp.745-750
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• 2008

Selenium, an essential trace element possessing anti-carcinogenic properties, can induce apoptosis in cancer cells. We have previously shown that sodium selenite can induce apoptosis by activating the mitochondrial apoptosis pathway in NB4 cells. However, the detailed mechanism remains unclear. Presently, we demonstrate that p53 contributes to apoptosis by directing signaling at the mitochondria. Immunofluorescent and Western blot procedures revealed selenite-induced p53 translocation to mitochondria. Inhibition of p53 blocked accumulation of reactive oxygen species (ROS) and loss of mitochondrial membrane potential, suggesting that mitochondrial p53 acts as an upstream signal of ROS and activates the mitochondrial apoptosis pathway. Selenite also disrupted cellular calcium ion homeostasis in a ROS-dependent manner and increased mitochondrial calcium ion concentration. p38 kinase mediated phosphorylation and mitochondrial translocation of p53. Taken together, these results indicate that p53 involves selenite-induced NB4 cell apoptosis by translocation to mitochondria and activation mitochondrial apoptosis pathway in a transcription-independent manner.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.338-351
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• 2003

UV radiation is the most dangerous stress factor among permanent environmental impacts on human skin. Consequences of UV exposure are aberrant tissue architecture, alterations in skin cells including functional changes. Nowadays new kinds of outdoor leisure-time activities and changing environmental conditions make the question of sun protection more important than ever. It is necessary to recognize that self-confident consumers do not consider to change their way of life, they demand modern solutions on the basis of new scientific developments. In the past one fundamental principle of cosmetics was the use of physical and organic filter systems against damaging UV-rays. Today new research results demonstrate that natural protecting cell mechanisms can be activated. Suitable biological actives strongly support the protection function not from the surface but from the inside of the cell. A soy seed preparation (SSP) was proven to stimulate natural skin protective functions. The major functions are an increased energy level and the prevention of DNA damage. These functions can I be defined as biological UV protection. The tumor suppressor protein p53 plays a key role in the regulation of DNA repair. p53 must be transferred into the phosphorylated form to work as transcription factor for genes which are regulating the cell cycle or organizing DNA repair. A pretreatment with SSP increases the phosphorylation rate of p53 of chronically UV-irradiated human keratinocytes significantly. According to the same test procedure SSP induces a dramatic increase in the expression of the tumor suppressor protein p14$^{ARF}$ that is supporting the p53 activity by blocking the antagonist of p53, the oncoprotein Mdm2. Mdm2, a ubiquitin E3-ligase, downregulates p53 and at the same time it prevents phosphorylation of p53. The positive influence of the tumor suppressor proteins explains the stimulation of DNA repair and prevention of sunburn cell formation by SSP, which was proven in cell culture experiments. In vivo the increased skin tolerance against UV irradiation by SSP could be confirmed too. We have assumed, that an increased repair potential provides full cell functionality.y.

• Tuberculosis and Respiratory Diseases
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• v.50 no.1
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• pp.67-75
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• 2001

Background : Two tumor suppressor genes, p53 and p16, which have different roles in controlling the cell cycle and inducing apoptosis, are frequently inactivated during carcinogenesis including lung cancer. Single tumor suppressor gene therapies using either with p53 or p16 have been studied extensively. However, there is a paucity of reports regarding a combined gene therapy using these two genes. Methods : The combined effect of p53 and p16 gene transfer by the adenoviral vector on the growth of lung cancer cell lines and its interactive mechanism was investigated. Results : An isobologram showed that the co-transduction of p53 and p16 exhibited a synergistic growth in hibitory effect on NCI H358 and an additive effect on NCI H23. Cell cycle analysis demonstrated the induction of a synergistic G1/S arrest by a combined p53 and p16 transfer. This synergistic interaction was again confirmed in a soft agar confirmed in a soft agar clonogenic assay. Conclusion : These observations suggest the potential of a p53 and p16 combination gene therapy as another potent strategy in cancer gene therapy.

• Molecules and Cells
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• v.45 no.10
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• pp.718-728
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• 2022

Splicing factor B subunit 4 (SF3B4), a component of the U2-pre-mRNA spliceosomal complex, contributes to tumorigenesis in several types of tumors. However, the oncogenic potential of SF3B4 in lung cancer has not yet been determined. The in vivo expression profiles of SF3B4 in non-small cell lung cancer (NSCLC) from publicly available data revealed a significant increase in SF3B4 expression in tumor tissues compared to that in normal tissues. The impact of SF3B4 deletion on the growth of NSCLC cells was determined using a siRNA strategy in A549 lung adenocarcinoma cells. SF3B4 silencing resulted in marked retardation of the A549 cell proliferation, accompanied by the accumulation of cells at the G0/G1 phase and increased expression of p27, p21, and p53. Double knockdown of SF3B4 and p53 resulted in the restoration of p21 expression and partial recovery of cell proliferation, indicating that the p53/p21 axis is involved, at least in part, in the SF3B4-mediated regulation of A549 cell proliferation. We also provided ubiquitination factor E4B (UBE4B) is essential for p53 accumulation after SF3B4 depletion based on followings. First, co-immunoprecipitation showed that SF3B4 interacts with UBE4B. Furthermore, UBE4B levels were decreased by SF3B4 depletion. UBE4B depletion, in turn, reproduced the outcome of SF3B4 depletion, including reduction of polyubiquitinated p53 levels, subsequent induction of p53/p21 and p27, and proliferation retardation. Collectively, our findings indicate the important role of SF3B4 in the regulation of A549 cell proliferation through the UBE4B/p53/p21 axis and p27, implicating the therapeutic strategies for NSCLC targeting SF3B4 and UBE4B.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.24
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• pp.10653-10658
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• 2015

Background: A very high incidence of lung cancer is observed in Mizoram and Manipur, North East India. We conducted a population based case control study to establish associations of p53 codon 72 polymorphisms and interactions with environmental factors for this high incidence. Material and Methods: A total of 272 lung cancer cases and 544 controls matched for age (${\pm}5years$), sex and ethnicity were collected and p53 codon 72 polymorphism genotypes were analyzed using a polymerase chain based restriction fragment length polymorphism assay. We used conditional multiple logistic regression analysis to calculate adjusted odds ratios and 95% confidence intervals after adjusting for confounding factors. Results: p53 Pro/Pro genotype was significantly associated with increased risk of lung cancer in the study population (adjusted OR=2.14, CI=1.35-3.38, p=0.001). Interactions of the p53 Pro/Pro genotype with exposure to wood smoke (adjusted OR=3.60, CI=1.85-6.98, p<0.001) and cooking oil fumes (adjusted OR=3.27, CI=1.55-6.87, p=0.002), betel quid chewing (adjusted OR=3.85, CI=1.96-7.55, p<0.001), tobacco smoking (adjusted OR=4.42, CI=2.27-8.63, p<0.001) and alcohol consumption (adjusted OR=3.31, CI=1.10-10.03, p=0.034) were significant regarding the increased risk of lung cancer in the study population. Conclusions: The present study provided preliminary evidence that a p53 codon 72 polymorphism may effect lung cancer risk in the study population, interacting synergistically with environmental factors.