Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The panel of 60 human cancer cell lines (the NCI-60) assembled by the National Cancer Institute for anticancer drug discovery is a widely used resource. We previously sequenced 24 cancer genes in those cell lines. Eleven of the genes were found to be mutated in three or more of the lines. Using a pharmacogenomic approach, we analyzed the relationship between drug activity and mutations in those 11 genes (APC, RB1, KRAS, NRAS, BRAF, PIK3CA, PTEN, STK11, MADH4, TP53, and CDKN2A). That analysis identified an association between mutation in BRAF and the antiproliferative potential of phenothiazine compounds. Phenothiazines have been used as antipsychotics and as adjunct antiemetics during cancer chemotherapy and more recently have been reported to have anticancer properties. However, to date, the anticancer mechanism of action of phenothiazines has not been elucidated. To follow up on the initial pharmacologic observations in the NCI-60 screen, we did pharmacologic experiments on 11 of the NCI-60 cell lines and, prospectively, on an additional 24 lines. The studies provide evidence that BRAF mutation (codon 600) in melanoma as opposed to RAS mutation is predictive of an increase in sensitivity to phenothiazines as determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt assay (Wilcoxon P = 0.007). That pattern of increased sensitivity to phenothiazines based on the presence of codon 600 BRAF mutation may be unique to melanomas, as we do not observe it in a panel of colorectal cancers. The findings reported here have potential implications for the use of phenothiazines in the treatment of V600E BRAF mutant melanoma.
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PMID:In vitro differential sensitivity of melanomas to phenothiazines is based on the presence of codon 600 BRAF mutation. 1852 47

Loss of genomic imprinting is an epigenetic alteration of some cancers involving the absence of parental origin-specific expression of imprinted genes. Loss of genomic imprinting of insulin-like growth factor II is often detected in colorectal cancer. However, the genetic alterations accompanied by colorectal cancer with insulin-like growth factor II loss of genomic imprinting have not been fully determined. Genomic DNA samples were collected from 52 colorectal cancer tissues and analyzed. The loss of insulin-like growth factor II genomic imprinting status was determined by assessing the demethylation of the insulin-like growth factor II differentially methylated region using bisulfite sequencing. The molecular signatures were also examined: genetic mutations of KRAS, BRAF, and PIK3CA; the expression of CTNNB1 and TP53; and microsatellite instability status. Several cases of colorectal cancer with normal insulin-like growth factor II imprinting were located in the distal colon; in contrast, colorectal cancer with loss of genomic imprinting tended to be found in the proximal colon (22.7 versus 56.6%). The PIK3CA gene mutation was highly detected in normal imprinting tumors compared to colorectal cancers with insulin-like growth factor II loss of genomic imprinting (27.3% versus 6.7%). In multivariate analysis of these clinicopathologic and molecular factors of tumors, statistically significant relationships were observed among the proximal location of the tumor (odds ratio, 12.9; 95% confidence interval, 1.52-110.13), PIK3CA genetic mutation (odds ratio, 0.082; 95% confidence interval, 0.01-0.73), and insulin-like growth factor II genomic imprinting status. Our findings indicate that colorectal cancers with demethylation of the insulin-like growth factor II gene are distinct from normal imprinting tumors, both in clinical and genetic features.
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PMID:Genetic alterations in colorectal cancers with demethylation of insulin-like growth factor II. 1861 47

PIK3CA mutations at 9 and 20 exons were studied in a series of 56 selected aggressive breast carcinomas (BC): 27 with Her-2 over-expression and negativity for estrogen receptors (ER) and progesterone receptors (PR), and 29 "triple negative" BC (negative for ER, PR and Her-2). Also, immunohistochemical studies of p53, ki-67, Her-1 (EGFR), pIGF-1R, PTEN, p110alpha, and pAkt were performed. Six mutations in exon 20 PIK3CA were identified among the 27 Her-2 positive BC, whereas only one exon 9 PIK3CA mutation was detected in a triple negative tumor (p = 0.035). Furthermore, PIK3CA mutations were associated with p110alpha over-expression (p = 0.001). Overall survival was shorter in cases with PIK3CA mutations (p = 0.015 in all series; and p = 0.041 for Her-2+ tumors), although multivariate analyses did not show statistical differences. No statistical significance was related with disease-free survival. Exon 20 PIK3CA mutations are relatively frequent in Her-2+ tumors and shorten survival, whereas neither exons 9 and 20 mutations seem related with "triple negative" breast carcinomas.
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PMID:Exon 20 PIK3CA mutations decreases survival in aggressive (HER-2 positive) breast carcinomas. 1867 14

The role of gene mutations in tumourigenesis is well understood, however, the mechanism(s) by which they arise are less clear. Indeed, the common assumption that tumourigenic mutations are the result of DNA replication errors is apparently contradicted by the very low division frequency of the cells from which tumours are thought to arise (i.e. deep stem cells). As a potential solution to this paradox, we tested a model whereby clustered DNA lesion sites (CLS) (where several lesions occur within a few base pairs of each other on opposing strands) could give rise to mutations in quiescent cells. We used statistical analyses to search for sets of dinucleotide sequences (designated target sequences) that are present at and in close proximity to mutation sites in four genes associated with human colorectal tumourigenesis (adenomatosis polyposis coli (APC), v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS), phosphoinositide-3-kinase, catalytic, alpha polypeptide (PIK3CA), and tumour protein p53 (TP53)). The dinucleotides CG, AC-GT, TG, and GC were identified as target sequences in at least three of the genes analysed. Consistent with their designation as target sequences, these dinucleotides have all been identified as high probability sites of oxidative damage formation in in vitro studies. Our results strongly suggest a statistical association between the presence of multiple, clustered target sequences and mutational events. We propose that CLS are a major source of mutations during human tumourigenesis.
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PMID:Clustered DNA lesion sites as a source of mutations during human colorectal tumourigenesis. 1882 8

This article reviews the main molecular alterations involved in endometrial carcinoma. Five molecular features (microsatellite instability, and mutations in the PTEN, k-RAS, PIK3CA and beta-catenin genes) are characteristic of endometrioid carcinomas, whereas non-endometrioid carcinomas show alterations of p53, loss of heterozygosity (LOH) on several chromosomes, as well as other molecular alterations (STK15, p16, E-cadherin and C-erb B2). The review also covers the phenomenon of apoptosis resistance, as well as the results obtained from cDNA array studies, and the perspectives for targeted therapies. A group of practical applications of molecular pathology techniques are also mentioned: diagnosis of hereditary non-polyposis colon cancer syndrome in patients with endometrial carcinoma; evaluation of precursor lesions; prognosis; diagnosis, particularly for synchronous endometrioid carcinomas of the uterus and the ovaries; and targeted therapies.
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PMID:Molecular pathology of endometrial carcinoma: practical aspects from the diagnostic and therapeutic viewpoints. 1897 6

Anaplastic thyroid cancer (ATC) is a rare malignancy. While external beam radiation therapy has improved locoregional control, the median survival of approximately 4 months has not changed in more than half a century due to uncontrolled systemic metastases. The objective of this study was to review the literature in order to identify potential new strategies for treating this highly lethal cancer. PubMed searches were the principal source of articles reviewed. The molecular pathogenesis of ATC includes mutations in BRAF, RAS, catenin (cadherin-associated protein), beta 1, PIK3CA, TP53, AXIN1, PTEN, and APC genes, and chromosomal abnormalities are common. Several microarray studies have identified genes and pathways preferentially affected, and dysregulated microRNA profiles differ from differentiated thyroid cancers. Numerous proteins involving transcription factors, signaling pathways, mitosis, proliferation, cell cycle, apoptosis, adhesion, migration, epigenetics, and protein degradation are affected. A variety of agents have been successful in controlling ATC cell growth both in vitro and in nude mice xenografts. While many of these new compounds are in cancer clinical trials, there are few studies being conducted in ATC. With the recent increased knowledge of the many critical genes and proteins affected in ATC, and the extensive array of targeted therapies being developed for cancer patients, there are new opportunities to design clinical trials based upon tumor molecular profiling and preclinical studies of potentially synergistic combinatorial novel therapies.
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PMID:Anaplastic thyroid cancer: molecular pathogenesis and emerging therapies. 1898 68

PI3K/AKT signalling pathway controls important cellular processes such as the cell proliferation and apoptosis. PIK3CA gene encoding a catalytic subunit of the PI3K is mutated and/or amplified in various neoplasms, including ovarian cancer. We aimed to evaluate PIK3CA alterations and their clinical importance in ovarian cancer patients. Molecular analysis was performed on 117 ovarian carcinomas with the use of qPCR, SSCP and sequencing. In a group of 98 patients with complete clinical data, 62 patients were treated with standard taxane-platinum regimens and 36 patients with platinum-cyclophosphamide regimens. A multivariate analysis was performed by the Cox's and logistic regression models. PIK3CA mutations occurred in 5/117 (4.3%) carcinomas, exclusively in the endometrioid and clear cell types (p = 0.0002); they were also associated with low FIGO stage (p = 0.0003), low tumor grade (p = 0.045) and early patient's age at diagnosis (p = 0.0005). The PIK3CA amplification (predominantly a low-level) was found in 28/117 (24%) ovarian carcinomas. It was more frequent in TP53 mutant tumors (p = 0.012) and tended to associate with high pAKT expression (p = 0.061). The PIK3CA amplification strongly diminished odds of complete remission (OR = 0.25, p = 0.033) and platinum sensitive response (PS, OR = 0.12, p = 0.004) in the taxane-platinum treated patients. The odds of PS were also much lower in all patients with the PIK3CA amplification evaluated together, regardless of the treatment applied (OR = 0.18, p = 0.001). Our results suggest that PIK3CA amplification may be a marker predicting ovarian cancer response to chemotherapy.
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PMID:PIK3CA amplification associates with resistance to chemotherapy in ovarian cancer patients. 1912 16

Transitional cell tumors of the ovary include 2 distinct clinicopathologic categories: Brenner tumors and transitional cell carcinomas (TCCs). Their molecular genetic alterations have not been fully investigated. We have performed a clinicopathologic, immunohistochemical, and molecular genetic analysis of 19 transitional cell tumors including 13 Brenner tumors (5 benign, 7 borderline, and 1 malignant) and 6 TCCs. Immunoreactivity for epidermal growth factor receptor (EGFR), Ras, Cyclin D1, p16, Rb, and p53, as well as fluorescence in situ hybridization analysis for EGFR were assessed in all cases. Screening for mutations in K-Ras, B-Raf, CTNNB1, PIK3CA, and p53 genes was also performed. The mean patient age was 58 years (range, 32 to 85 y). Abdominal enlargement and pain were the usual complaints. Treatment was known in 14 patients: 10 had hysterectomy with bilateral salpingo-oophorectomy, which was accompanied by omentectomy in 7; and 4 had only unilateral or bilateral salpingo-oophorectomy, 1 with omentectomy. Four patients had brachytherapy. Six borderline Brenner tumors were stage IA and 1 stage IIA. The malignant Brenner tumor was stage IA. One TCC was stage IA, one IC, 2 IIIC and the stage was unknown in 2 cases. Follow-up information was available only in 5 of the nonbenign cases. Two patients who had borderline Brenner tumors were alive and well at 3 and 10.9 years. The patient who had a malignant Brenner tumor died of pulmonary thromboembolism shortly postoperatively, and 2 patients with TCCs died of tumor 1.8 and 13 years, postoperatively. Brenner tumors and TCCs differed mainly in the expression of EGFR, p16, and p53. Benign Brenner tumors showed a low immunoexpression for all markers. Borderline Brenner tumors failed to immunoreact for p16, Rb, and p53; and showed weak immunostaining for Cyclin D1, moderate for Ras, and strong for EGFR. The malignant Brenner tumor was also negative for p16, Rb, and p53, and strongly positive for Cyclin D1, Ras, and EGFR. In contrast, TCCs had p53 mutations with p53 and p16 protein overexpression and showed a negative immunoreaction for EGFR, Cyclin D1, and Ras. Our results suggest that Brenner tumors and TCCs follow different tumorigenic pathways, whereas borderline and malignant Brenner tumors are low-grade neoplasms with activation of the PI3K/AKT pathway through EGFR, TCCs are high-grade tumors that have p53 mutations and p16 and p53 protein overexpression.
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PMID:Transitional cell tumors of the ovary: a comparative clinicopathologic, immunohistochemical, and molecular genetic analysis of Brenner tumors and transitional cell carcinomas. 1903 64

The incidence of colorectal carcinoma has increased among patients <40 years of age for unclear reasons. In this study, we describe the clinical, pathologic, and molecular features of colorectal carcinomas that developed in young patients. We compiled a study group of 24 patients <40 years of age with colorectal carcinoma, and 45 patients > or =40 years of age served as controls. Cases were evaluated for clinical risk factors of malignancy and pathologic features predictive of outcome. The tumors were immunohistochemically stained for O6-methylguanine methyltransferase, MLH-1, MSH-2, MSH-6, beta-catenin, chemokine (C-X-C motif) receptor 4, epidermal growth factor receptor, TP53, p16, survivin, and alpha-methylacyl-CoA racemase; assessed for microsatellite instability and mutations in beta-catenin, APC, EGFR, PIK3CA, KRAS, and BRAF; evaluated for micro-RNA expression (miR-21, miR-20a, miR-183, miR-192, miR-145, miR-106a, miR-181b, and miR-203); and examined for evidence of human papillomavirus infection. One study patient each had ulcerative colitis and hereditary nonpolyposis colorectal cancer. Ninety-two percent of tumors from young patients occurred in the distal colon (P=0.006), particularly the rectum (58%, P=0.02), and 75% were stage III or IV. Tumors from young patients showed more frequent lymphovascular (81%, P=0.03) and/or venous (48%, P=0.003) invasion, an infiltrative growth pattern (81%, P=0.03), and alpha-methylacyl-CoA racemase expression (83%, P=0.02) compared with controls. Carcinomas in this group showed significantly increased expression of miR-21, miR-20a, miR-145, miR-181b, and miR-203 (P< or =0.005 for all comparisons with controls). These results indicate that early-onset carcinomas commonly show pathologic features associated with aggressive behavior. Posttranslational regulation of mRNA and subsequent protein expression may be particularly important to the development of colorectal carcinomas in young patients.
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PMID:Clinical, pathologic, and molecular features of early-onset colorectal carcinoma. 1904 96

JC virus has a transforming gene encoding JC virus T-antigen (JCVT). JCVT may inactivate wild-type p53, cause chromosomal instability (CIN), and stabilize beta-catenin. A link between JCVT and CpG island methylator phenotype (CIMP) has been suggested. However, no large-scale study has examined the relations of JCVT with molecular alterations, clinical outcome, or prognosis in colon cancer. We detected JCVT expression (by immunohistochemistry) in 271 (35%) of 766 colorectal cancers. We quantified DNA methylation in eight CIMP-specific promoters (CACNA1G, CDKN2A, CRABP1, IGF2, MLH1, NEUROG1, RUNX3, and SOCS1) and eight other loci (CHFR, HIC1, IGFBP3, MGMT, MINT1, MINT31, p14, WRN) by MethyLight. We examined loss of heterozygosity in 2p, 5q, 17q, and 18q. JCVT was significantly associated with p53 expression (P < .0001), p21 loss (P < .0001), CIN (>/=2 chromosomal segments with LOH; P < .0001), nuclear beta-catenin (P = .006), LINE-1 hypomethylation (P = .002), and inversely with CIMP-high (P = .0005) and microsatellite instability (MSI) (P < .0001), but not with PIK3CA mutation. In multivariate logistic regression analysis, the associations of JCVT with p53 [adjusted odds ratio (OR), 8.45; P < .0001], CIN (adjusted OR, 2.53; P = .003), cyclin D1 (adjusted OR, 1.57; P = .02), LINE-1 hypomethylation (adjusted OR, 1.97 for a 30% decline as a unit; P = .03), BRAF mutation (adjusted OR, 2.20; P = .04), and family history of colorectal cancer (adjusted OR, 0.64; P = .04) remained statistically significant. However, JCVT was no longer significantly associated with CIMP, MSI, beta-catenin, or cyclooxygenase-2 expression in multivariate analysis. JCVT was unrelated with patient survival. In conclusion, JCVT expression in colorectal cancer is independently associated with p53 expression and CIN, which may lead to uncontrolled cell proliferation.
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PMID:JC virus T-antigen in colorectal cancer is associated with p53 expression and chromosomal instability, independent of CpG island methylator phenotype. 1910 35


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