p53 and its isoforms in DNA double-stranded break repair / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

DNA double-stranded break (DSB) is one of the most catastrophic damages of genotoxic insult. Inappropriate repair of DNA DSBs results in the loss of genetic information, mutation, and the generation of harmful genomic rearrangements, which predisposes an organism to immunodeficiency, neurological damage, and cancer. The tumor repressor p53 plays a key role in DNA damage response, and has been found to be mutated in 50% of human cancer. p53, p63, and p73 are three members of the p53 gene family. Recent discoveries have shown that human p53 gene encodes at least 12 isoforms. Different p53 members and isoforms play various roles in orchestrating DNA damage response to maintain genomic integrity. This review briefly explores the functions of p53 and its isoforms in DNA DSB repair.

MicroRNA-mRNA functional pairs for cisplatin resistance in ovarian cancer cells / 癌症

Ovarian cancer is the leading cause of death in women worldwide. Cisplatin is the core of first-line chemotherapy for patients with advanced ovarian cancer. Many patients eventually become resistant to cisplatin, diminishing its therapeutic effect. MicroRNAs (miRNAs) have critical functions in diverse biological processes. Using miRNA profiling and polymerase chain reaction validation, we identified a panel of differentially expressed miRNAs and their potential targets in cisplatin-resistant SKOV3/DDP ovarian cancer cells relative to cisplatin-sensitive SKOV3 parental cells. More specifically, our results revealed significant changes in the expression of 13 of 663 miRNAs analyzed, including 11 that were up-regulated and 2 that were down-regulated in SKOV3/DDP cells with or without cisplatin treatment compared with SKOV3 cells with or without cisplatin treatment. miRNA array and mRNA array data were further analyzed using Ingenuity Pathway Analysis software. Bioinformatics analysis suggests that the genes ANKRD17, SMC1A, SUMO1, GTF2H1, and TP73, which are involved in DNA damage signaling pathways, are potential targets of miRNAs in promoting cisplatin resistance. This study highlights candidate miRNA-mRNA interactions that may contribute to cisplatin resistance in ovarian cancer.

Relationship between mRNA expression and promoter methylation status of p73 gene in peripheral blood among children with Wilms' tumor / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the mRNA expression and promoter methylation status of p73 gene in the peripheral blood of children with Wilms' tumor (WT), and their relationship.</p><p><b>METHODS</b>Forty-five children with WT were selected as the case group, and 15 sex- and age- matched children (without malignancies) who visited the hospital for physical examination or other reasons were selected as the control group. Peripheral blood was collected from both groups. Real-time quantitative PCR and methylation-specific PCR were used to determine the mRNA expression level and promoter methylation status of p73 gene. Their relationship with clinicopathological features and the effect of promoter methylation on mRNA expression of p73 gene were analyzed in the case group.</p><p><b>RESULTS</b>The relative quantity (RQ) of p73 mRNA in the case group was significantly higher than in the control group (3.2 ± 0.9 vs 1.6 ± 1.1; P<0.01). The positive rate of p73 gene promoter methylation in the case group was significantly lower than in the control group (20% vs 73%; P<0.01). In the case group, the RQ of p73 mRNA was significantly higher in children with methylated p73 gene promoter than in those with unmethylated p73 gene promoter (P<0.01). In children with methylated p73 gene promoter, the RQ of p73 mRNA was significantly higher in the case group than in the control group (P<0.01). In children with unmethylated p73 gene promoter, there was no significant difference in RQ of p73 mRNA between the case and control groups (P=0.810).</p><p><b>CONCLUSIONS</b>Aberrant promoter methylation of p73 gene in peripheral blood is one of the gene expression regulations in children with WT, and it is related to the onset and development of WT. The p73 gene may play a role as oncogene in WT patients with p73 gene promoter methylation and mRNA overexpression is associated with promoter methylation status of p73 gene.</p>

Expression and promotor methylation of p73 gene in ovarian epithelial tumors / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the expression and promoter methylation status of p73 gene in ovarian epithelial tumors and their clinicopathological correlations.</p><p><b>METHODS</b>Tissue microarrays (TMA) consisting of 68 ovarian cancers, 37 ovarian borderline tumors and 21 ovarian benign tumors were constructed. p73 expression was detected by immunohistochemistry (EnVision method). Fresh-frozen tissue samples from 13 cases of ovarian carcinomas and 5 cases of borderline tumors were evaluated for the presence of p73 promoter methylation using bisulfite sequencing.</p><p><b>RESULTS</b>Overall, 92.6% (63/68) ovarian carcinomas expressed p73, with a mean value of 32% (percentage of p73 positive cells in the tumor). The mean value of p73 expression rate (40%) in serous carcinoma (26/26) was higher than those of other cancer types (P = 0.006). The mean value of p73 expression rate (40%) in type II ovarian carcinoma was significantly higher than that in type I ovarian carcinoma (24%, P = 0.010). The expression of p73 was not associated with FIGO stage and histological grade (both P > 0.05). The mean values of p73 expression in ovarian borderline tumor (30/37) and benign tumor (12/21) were 16% and 15%, respectively. Of the two groups, the mean value of p73 expression rate in serous type was higher than that in mucous type (P = 0.003, P = 0.026). Ovarian carcinomas had a higher level of p73 expression than borderline tumors and benign tumors (both P < 0.05), while that between ovarian borderline tumors and benign tumors had no statistical difference (P > 0.05). Among serous tumors (49/53), the mean value of p73 expression in the carcinoma group (26/26) was significantly higher than those in the borderline tumor group (12/14) and benign tumor group (11/13; P = 0.024 and P = 0.002, respectively), while that between borderline tumor group and benign tumor group had no statistical difference (P = 0.428). Among mucous tumors (15/27), the mean value of p73 expression in carcinoma group (6/7) was higher than that in benign tumor group (1/8; P = 0.032). No statistical difference of p73 expression was seen between the carcinoma group and ovarian borderline tumor group (8/12) and between the borderline tumor group and benign tumor group (P = 0.234, P = 0.201, respectively). p73 promotor methylation was found in 8 of 13 cases of carcinomas but at different methylation levels with a mean value of 8.0%. Two of 5 ovarian borderline tumors showed detectable p73 promotor methylation with a mean value of 9.0%. Compared with the borderline tumors, ovarian carcinomas showed a similar p73 methylation level (P > 0.05). The p73 methylation level in ovarian carcinomas was not associated with histological type, pathogenetic type, histological grade and FIGO stage (all P > 0.05).</p><p><b>CONCLUSIONS</b>Most of ovarian epithelial tumors express p73 protein with mean values higher in ovarian carcinomas than those in the borderline and benign tumors. Ovarian serous carcinomas have the highest expression level of p73. A simple linear correlation does not exist between the promoter methylation and protein expression of p73.</p>

Study of aberrant p73 promoter methylation in patients with myelodysplastic syndrome / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the methylation status of p73 gene promoter in patients with myelodysplastic syndrome (MDS) and explore its significance with clinical prognosis.</p><p><b>METHODS</b>Methylation of p73 promoter was detected in bone marrow cells from 135 MDS patients and 13 healthy controls by methylation-specific PCR (MSP). The results of MSP were confirmed by bisulfite sequencing. The expression of p73 mRNA was detected by real-time quantitative PCR. Primary bone marrow cells from MDS patients were treated with decitabine, the changes of p73 methylation status and p73 mRNA expression were measured. The role of p73 methylation in the prognosis of MDS and the correlated clinical data were explored.</p><p><b>RESULTS</b>p73 hypermethylation was present in 37.04% of MDS cases and patients with high risk MDS (RAEB-1 and RAEB-2) exhibited a significantly higher frequency of p73 methylation than that of low risk MDS (58.8% vs 29.7%, P = 0.002). The expression of p73 mRNA in the methylated group was decreased compared to that of the unmethylated group (P = 0.032). Decitabine treatment decreased the level of p73 methylation and increased the level of p73 transcripts. Patients with p73 methylation progressed rapidly to AML (P < 0.001) and had shorter survival (P = 0.002) than those who did not have p73 methylation. In the multivariate Cox regression model, BM blast and p73 methylation status emerged as independent prognostic factor for overall survival and leukemia free survival.</p><p><b>CONCLUSION</b>p73 gene methylation is common in patients with MDS and may indicate poor prognosis. p73 may be a therapeutic target in MDS.</p>

p73 polymorphisms and clinicopathologic characteristics in breast cancer / 中南大学学报(医学版)

OBJECTIVE@#To evaluate the correlations between p73 G4C14-A4T14 polymorphisms and clinicopathologic characteristics of patients with breast cancer.@*METHODS@#A total of 170 patients with breast cancer were genotyped for p73 G4C14-A4T14 polymorphisms by Sequenom MassArray® iPLEX GOLD System. The correlations between polymorphisms and the age of patients with breast cancer, or tumor size were analyzed by t-test;the correlations between polymorphisms and clinicopathologic characteristics in patients with breast cancer were analyzed by Χ(2) test; and the relation between polymorphisms and the efficacy of chemotherapy for breast cancer was assessed by logistic regression.@*RESULTS@#There was negative correlation between p73 polymorphisms and ser veral clinicopathological characteristics, including age, tumor size, menopausal status, TNM classification, pathological type, axillary lymph node metastasis, estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, and p53(P>0.05). The frequency of GC/GC genotype in patients with "triple negative" breast cancer (estrogen receptor -negative, progesterone receptornegative, and human epidermal growth factor receptor 2-negative) was higher than that of patients with non-triple negative breast cancer (78.9% vs 57.6%, Χ(2)=5.741, P=0.017). P73 polymorphism was negatively correlated with chemosensitivity for anthracycline-based chemotherapy (P>0.05).@*CONCLUSION@#P73 G4C14-A4T14 polymorphisms are positively correlated with triple negative breast cancer, and the patients with breast cancer who carry GC/GC genotype may have bad prognosis.

Down-regulation of p73 correlates with high histological grade in Japanese with breast carcinomas / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>p73, a homologue of p53, has been located at chromosome 1p36-33, a region of frequently observed loss of heterozygosity in breast cancers. The objective of the present study was to investigate the function of p73 in Japanese with breast cancers.</p><p><b>METHODS</b>Sixty Japanese patients with breast cancer were assessed by polymerase chain reaction single strand confirmation polymorphism analysis and direct sequencing to detect the p73 allele. p73 mRNA levels were also determined in 40 out of 60 patients by reverse-transcriptional polymerase chain reaction.</p><p><b>RESULTS</b>We analyzed the entire open reading frame of the p73 gene by polymerase chain reaction single strand confirmation polymorphism and sequencing, and failed to identify any mutations of p73 in the encoding regions detected. Loss of heterozygosity of p73 was infrequent and only found in 9% of breast carcinomas. We revealed a few polymorphisms with a frequency of 13% - 29%, which had been reported previously. Down-regulation of p73 mRNA expression was observed in tumor tissues in comparison to the normal breast tissues. A significant inverse correlation was found between p73 transcripts and high histological grade, suggesting that down-regulated p73 expression could be related to poor prognosis in those patients.</p><p><b>CONCLUSION</b>Our results suggest that p73 may serve as a tumor suppressor gene and its expression plays a role in tumorigenesis in Japanese patients with breast cancer.</p>

Clinical significance of the expression of p53, p63 and p73 in nasal and paranasal sinus carcinoma / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To study the clinical significance of the expression of p53, p63 and p73 protein and the correlation of p53 and p63 in nasal and paranasal sinus carcinoma (NPSC).@*METHOD@#The immunohistochemical technique was used to detect the expression of p53, p63 and p73 in 67 cases of NPSC, para-cancer tissues and non-cancer tissues.@*RESULT@#The positive rate of p53 and p63 protein in NPSC was significantly higher than that in park cancer tissues and non-cancer tissues (P0.05).@*CONCLUSION@#There are positive correlation between p53 and p63 protein in NPSC, and they may play an important role in the tumorgenesis of NPSC. The p73 may not be associated with tumorgenesis of NPSC.

Association of the responsiveness of advanced non-small cell lung cancer to platinum-based chemotherapy with p53 and p73 polymorphisms / 中华肿瘤杂志

<p><b>OBJECTIVE</b>It has been proposed that genetic polymorphisms in apoptosis-related genes might be associated with sensitivity of cancer cells to platinum-based chemotherapy. This study examined the relationship between p53 and p73 genetic polymorphisms and the response to platinum-based chemotherapy in patients with advanced non-small cell lung cancer (NSCLC).</p><p><b>METHODS</b>A total of 165 patients with advanced NSCLC treated with platinum-based chemotherapy were genotyped for the p53 codon 72 Pro-->Arg and p73 exon 2 G4C14-->A4T14 polymorphisms using PCR-RFLP and ARMS-PCR assays. Clinical response to the chemotherapy was obtained after 2 to 3 cycles. The adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using unconditional logistic regression model. All statistical tests were two-sided.</p><p><b>RESULTS</b>The p53 Pro allele carriers had higher response rate than non-carriers (OR = 2.46; 95% CI = 1.11 - 5.45). A higher response rate was also observed for the p73 G4C14/A4T14 or A4T14/A4T14 genotype, compared with the G4C14/G4C14 genotype (OR = 2.22; 95% CI = 1.14 - 4.30). When these two polymorphisms were combined to be analyzed, it was found that the response rate in those carrying the wild-type genotypes at both genes was only 7.7%, whereas the response rates in patients carrying 1, 2, or more than 2 variant alleles of p53 and p73 were 34.8%, 42.2% and 40.7%, respectively.</p><p><b>CONCLUSION</b>Those results suggest that p53 and p73 polymorphisms may be associated with clinical responsiveness to platinum-based chemotherapy in advanced NSCLC.</p>

Hypermethylation of Ras association domain family protein 1A, hypermethylated in cancer 1 and p73 genes in hepatocellular carcinoma / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the status of promoter hypermethylation of Ras association domain family protein 1A (RASSF1A), hypermethylated in cancer 1 (HIC1) and p73 genes in hepatocellular carcinoma (HCC) and to explore the correlation with clinicopathological features.</p><p><b>METHODS</b>Forty cases of HCC and their corresponding non-tumor liver tissues, other 2 cases of healthy donor livers were detected using methylation specific polymorphism chain reaction (MSP) method.</p><p><b>RESULTS</b>The frequency of promoter hypermethylation of RASSF1A showed 90.0% and 72.5% in tumor and corresponding non-tumor tissues respectively, and there was significant difference between them (P < 0.05). The frequency of promoter hypermethylation of HIC1 showed 77.5% and 70.0% in tumor and corresponding non-tumor tissues respectively. The frequency of hypermethylation of HIC1 in non-tumor liver tissues showed significant correlation between younger and older patients. The frequency of promoter hypermethylation of p73 showed 5.0% in tumor tissues. However, none of hypermethylation of the gene was detected in corresponding non-tumor liver tissues. There was none of hypermethylation of the three genes showed in two cases of healthy donor livers.</p><p><b>CONCLUSION</b>Promoter hypermethylation of RASSF1A and HIC1 genes are common event in HCC and play an important role in the pathogenesis and may be used to develop novel diagnostic and therapeutic approaches for HCC in the future.</p>

Association of two genetic polymorphisms in the 5'untranslated region of exon 2 of the p73 gene and risk of lung cancer / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the relationship between two potential functional polymorphisms in exon 2 of the p73 gene and the susceptibility of lung cancer.</p><p><b>METHODS</b>Genotypes were determined by polymerase chain reaction-single stand conformation polymorphism (PCR-SSCP) method in 425 histologically-confirmed lung cancer cases and 588 cancer-free controls, frequency-matched by age and sex.</p><p><b>RESULTS</b>The two polymorphisms were in complete linkage disequilibrium and the frequencies of variant p73 AT haplotype (A4T14) were less commonly seen in the cases (0.225) than in the controls (0.287) (P = 0.0018). Compared with the p73 GC/GC homozygotes, both the AT/AT variant homozygotes and GC/AT heterozygotes were associated with a significantly decreased risk [adjusted odds ratio (OR) = 0.45, 95% confidence interval (CI) = 0.26 - 0.80 and OR = 0.70, 95% CI = 0.53-0.92, respectively].</p><p><b>CONCLUSION</b>These results suggested that this p73 dinucleotide polymorphism might have had a role to play in the susceptibility of lung cancer.</p>

The expression of p73 and c-fos protein in hemangioma and its significance / 中华整形外科杂志

<p><b>OBJECTIVE</b>To investigate the expression of p73 and c-fos protein and its significance in the development of children hemangioma.</p><p><b>METHODS</b>The quantitative expressions of p73 and c-fos protein in hemangioma and normal skin were detected by immunohistochemistry.</p><p><b>RESULTS</b>The expressions of p73 and c-fos protein were strong in proliferative hemangioma while they were very weak in involutional hemangioma and normal skin. There were significant differences between the proliferative and involutional hemangioma or the normal skin in the expressions of p73 and c-fos (P < 0.01). No statistical significances of p73 or c-fos P73 expressions were observed between involutional hemangioma and normal skin (P > 0.05).</p><p><b>CONCLUSIONS</b>P73 and c-fos may play an important role in the development and involution of skin hemangioma.</p>

Expresión de p73 en relación con factores clínicos, patológicos y biológicos en tumores colorrectales / p73 expression in relation to factors clinical, pathological and biological colorectal tumors

Background: The p73 can inhibit cell growth and induce apoptosis, indicating that p73 is a p53-like tumour suppressor. However, studies have shown that either loss of heterozygosity (LOH) or mutation of p73 is not a common genetic event in tumour development. Material, methods and results: Western blotting was used for confirming the specificity of the p73 antibody. p73 expression was evaluated by using immunohistochemistry in 58 normal colorectal mucosa samples, 221 primary cancers and 58 lymph node metastases. PCR-restriction fragment length polymorphism was used for determining LOH in 52 primary tumours. The results showed that the frequency and the intensity of p73 immunostaining were markedly increased from normal tissue to primary tumour and to metastasis (p < 0.05). p73 overexpression predicted a worse prognosis outcome (p = 0.03), even after adjustment for patient's sex, age, tumour stage, growth pattern, and differentiation (p = 0.01). There was no LOH in primary tumours. Conclusion: The expression of p73 protein was up-regulated during the development from the normal mucosa to primary and to metastatic tumours. Furthermore, the overexpression of p73 was a predictor of poor prognosis in colorectal cancer patients. However, LOH of the gene was not an important factor in colorectal cancer development.

Antecedentes: La p73 puede inhibir el crecimiento celular e inducir apoptosis, lo cual indica que es un supresor de tumores, del tipo de p53. Sin embargo, los estudios demostraron que la pérdida de la heterocigotia (loss of heterozygosity, LOH) o la mutación de p73 no es un evento genético común en el desarrollo tumoral. Material, métodos y resultados: Para confirmar la especificidad del anticuerpo p73 se utilizó inmunotransferencia. Mediante inmunohistoquímica se evaluó la expresión de p73 en 58 muestras de mucosa colorrectal normal, en 221 muestras de cánceres primarios y en 58 muestras de ganglios linfáticos metastásicos. Se usó reacción en cadena de polimerasa y estudio de longitud de fragmentos de restricción para determinar LOH en 52 tumores primarios. Los resultados mostraron que la frecuencia y la intensidad de fijación de p73 aumentaron significativamente desde la evolución de tejido normal a tumores primarios y a metástasis (p < 0.05). La expresión exagerada de p73 predijo un pronóstico más desfavorable (p = 0.03) aun después del ajuste por sexo, edad, estadio tumoral, patrón de crecimiento y diferenciación (p = 0.01). No hubo LOH en tumores primarios. Conclusión: La expresión de la proteína p73 estuvo aumentada durante el pasaje de mucosa normal a tumores primarios y a metástasis. Más aun, la mayor expresión de p73 fue un factor predictivo de pronóstico desfavorable en pacientes con cáncer colorrectal. Sin embargo, la LOH del gen no fue un factor importante en la aparición de cáncer colorrectal.

Study on abnormal expression of the p73 gene in childhood acute lymphoblastic leukemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the relationship between p73 gene and the development and progression of childhood acute lymphoblastic leukemia (ALL).</p><p><b>METHODS</b>The levels of p73 transcripts in 61 ALL cell lines and 53 childhood ALL patients were assayed using reverse transcriptase-polymerase chain reaction (RT-PCR), and their relationship with the clinicopathological characteristics was analyzed. Besides, the methylation status of p73 exon 1 was analysed by restriction-enzyme related PCR, methylation-specific PCR and bisulfite genomic sequencing in the 61 ALL cell lines.</p><p><b>RESULTS</b>Of the 61 ALL cell lines, 42 showed expression of p73 mRNA, with a negative rate of 31.1%, and of the 53 primary childhood ALL samples, 39 showed expression of p73 mRNA, with a negative rate of 26.4%. Loss of p73 expression was significantly associated with the reduced disease free survival and overall survival of the patients. 39.3% (24/61) of the ALL cell lines showed hypermethylation of p73 exon 1, while normal lymphocytes and most cell lines expressed p73 mRNA were not hypermethylated.</p><p><b>CONCLUSION</b>There was a higher negative expression rate of p73 mRNA in childhood ALL. The main mechanism of the loss expression would be the hypermethylation of p73 gene. p73 gene inactivation might play an important role in the pathogenesis of ALL. Examination of p73 mRNA might have clinical significance in predicting prognosis of childhood ALL.</p>

p73 gene expression in apoptotic process of acute myeloid leukemia cell line U937 induced by methotrexate / 中国实验血液学杂志

The purpose of this investigation was to study the variation of p73 gene expression in the apoptotic process of acute myeloid leukemia (AML) cell line U937 induced by methotrexate (MTX). Morphological changes of apoptotic cells were observed with microscopy and Wright's + Giemsa staining. DNA ladder and cell cycle were examined by agarose gel electrophoresis and flow cytometry respectively. Using semi-quantitive reverse transcription-polymerase chain reaction (RT-PCR), the expression of p73 mRNA was examined. Results showed that MTX could induce U937 cell apoptosis effectively. Condensed nuclei, fragmentation of chromosome and DNA ladder were seen after 6 hour following treatment of MTX 5 micro mol/L. Sub-G(1) peak and S + G(2)/M arrest were also determined by FCM, but the quantity of p73 expression was generally constant. In conclusion, U937 cell apoptosis induced by MTX did not change p73 mRNA level.