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)

Betel quid (BQ) chewing has been a well-documented cause of oral epithelial lesions (OEL). Evolution from early hyperplastic lesions to the late or carcinomatous stage has been recognized. The pathobiological and molecular mechanism, however, remains to be elucidated. In this study, a total of 232 samples obtained from 153 cases of BQ-related OEL were retrospectively evaluated for the expression of p53 and bcl-2 in comparison with 26 cases of BQ-unrelated lesions (n = 29). The possible role of human papillomavirus (HPV) was also investigated. These BQ-related OELs included verrucous hyperplasia (VIH, n = 57, 24.6%), epithelial dysplasia (n = 23, 9.9%), verrucous carcinoma (VC, n = 5, 2.1%) and squamous cell carcinoma (SCC, n = 106, 45.7%). Fifty-four cases (35.3%) had multiple lesions. In comparison with the BQ-unrelated OELs, the characteristics of BQ-related OELs were a younger age, male predilection and multicentricity. In contrast to the tongue in BQ-unrelated OELs, the most common site for all types of BQ-related lesions was the buccal mucosa. Immunohistochemical studies of BQ-related lesions showed p53 staining in 30% of dysplasia and 38% of SCC, but a consistent absence in VH and VC. The cases with p53-positive SCC had a higher recurrence rate than p53-negative ones. Bcl-2 expression was negligible for all types of lesions. HPV-6/11 was detectable in 10% of dysplasia and 13% of SCC, but in neither VH nor VC. HPV-16/18, however, was consistently negative for all types of lesions. Our data suggest that p53, but not bcl-2, may play a role in tumor progression of BQ-related OELs, and that VH and VC are distinct and closely related histological lesions. The consistent absence of the malignant-type HPV in all BQ-related lesions suggests that HPV plays an insignificant role in the tumorigenesis of BQ-related oral cancers, although a cooperative role may exist between the benign-type HPV and BQ chewing.
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PMID:Pathological features of betel quid-related oral epithelial lesions in taiwan with special emphasis on the tumor progression and human papillomavirus association. 1241 91

Calpain, also named CAPN (for calcium-activated neutral protease), is a ubiquitous intracellular cytoplasmic non-lysosomal cysteine endopeptidase that requires calcium ions to exert its activity. Two major isoenzymes are known- micro -calpain (CAPN1) and m-calpain (CAPN2)-requiring micromolar and millimolar calcium concentrations for activation, respectively. Many known substrates of the different calpain isoenzymes, such as the transcription factors c-Fos and c-Jun, the tumour suppressor protein p53, protein kinase C, pp60src, or the adhesion molecule integrin, have been implicated in the pathogenesis of various malignancies including squamous (SCC) and basal (BCC) cell carcinomas of human skin, suggesting an important role of the calpain isoenzymes in malignant diseases. We have analysed the expression of CAP1 and CAPN2 protein and mRNA expression in BCCs and SCCs of human skin. Interestingly, CAPN1 immunoreactivity (streptavidin-peroxidase technique) was markedly reduced in BCCs compared to normal human skin or SCCs, while in contrast CAPN1 mRNA levels (determined by real-time PCR) were markedly elevated in BCCs and SCCs compared to normal human skin. No differences were found analysing CAPN2 protein and mRNA expression in normal human skin, BCCs and SCCs. In conclusion, we have demonstrated for the first time alterations in calpain mRNA expression and protein content in malignant skin tumours that may be of importance for the tumorigenesis and growth characteristics of BCCs and SCCs. However, our results do not allow conclusions on the function of CAPN1 and CAPN2 in BCCs and SCCs. It is not known if the CAPN genes in BCCs or SCCs exhibit functionally inactivating mutations or whether decreased CAPN1 protein expression in BCCs and elevated CAPN1 mRNA in BCCs and SCCs reflect a feedback loop coupled with increased degradation or proteolysis of CAPN1 protein.
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PMID:Different expression patterns of calpain isozymes 1 and 2 (CAPN1 and 2) in squamous cell carcinomas (SCC) and basal cell carcinomas (BCC) of human skin. 1263 42

In order to analyse the radiosensitivity of tumours and to evaluate the possibility of improving the treatment results with regard to genetic alterations, we examined 33 patients with advanced head and neck tumours after 66-70 Gy irradiation. Between 1998 and 2001, 33 patients with advanced head and neck squamous cell carcinoma (HN-SCC) were observed. They received 66-70 Gy to the primary tumour site and pathological lymph nodes. One month later, physical examination and CT were performed to verify the effect of radiotherapy, and the patients were followed until their death. The histological grading and Ki-67, cyclin D1, p53 and bcl-2 status were examined from the aspect of their potential prognostic value in all patients. The average survival was 13 months; 25% of the patients survived for at least 20 months. Seventy-two percent of the patients demonstrated Ki-67 positivity, 69% p53 positivity and 40% cyclin D1 positivity; there were only 12% bcl-2-positive cases. A significant correlation was not found between the tumour response or the duration of survival and the Ki-67, p53 or cyclin D1 positivity. Only bcl-2-positive cases exhibited significantly better outcome. These parameters indicate the proliferating (Ki-67 and cyclin D1) and apoptotic (p53 and bcl-2) activities of advanced HN-SCC cells. Our results proved that they proliferate rapidly and have impaired repair or apoptotic functions. The heterogeneity of our results did not allow us to conclude that the above parameters are of clinically reliable prognostic value, but the obviously high kinetic activity of HN-SCC underlines the potential efficacy and need for accelerated irradiation in these cases.
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PMID:Ki-67, cyclin D1, p53 and bcl-2 expression in advanced head and neck cancer. 1265 98

Previous studies have shown early region 1A (E1A) gene to inhibit the proliferation of tumour cells with wild-type, but not mutant, p53. E1A has also been shown to downregulate c-erb-B-2/neu expression, resulting in inhibition of growth in c-erb-B-2/neu overexpressing tumour cells. In this study, we have investigated the effect of E1A expression on four head and neck squamous cell carcinoma (HNSCC) cell lines that do not overexpress c-erb-B-2/neu. Cell cycle and Western blot analysis show E1A-mediated induction of apoptosis in all cell lines examined. This induction of apoptosis was independent of the p53 status as it occurred in the cell lines with wild-type, mutated or deleted p53. However, there was no evidence of E1A-induced apoptosis in a p53(+ve) normal human fibroblast cell line, 1BR3. Analysis of apoptosis in the SCC cell lines demonstrated E1A-mediated downregulation of EGFR, which was overexpressed in each of these cell lines. Overexpression of an exogenously introduced EGFR, under the control of an E1A-insensitive heterologous promoter, blocked E1A induction of apoptosis in these cells. Therefore, E1A-mediated downregulation of EGFR expression appears to be the cause, rather than a consequence of E1A-induced apoptosis in these SCC cell lines. Previous studies have shown downregulation of EGFR expression by PML. Interestingly, E1A expression in the HNSCC cells altered the pattern of PML distribution and induced the level of PML protein, thus suggesting that E1A-mediated downregulation of EGFR may occur via direct or indirect interactions with PML. These findings demonstrate a novel pathway by which E1A can induce apoptosis and identify EGFR as a potential target for the development of therapeutic strategies against epithelial malignancies, the majority of which have abnormal EGFR expression.
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PMID:E1A-mediated suppression of EGFR expression and induction of apoptosis in head and neck squamous carcinoma cell lines. 1267 2

This study was designed to: (a) evaluate the induction of hyper-radiation sensitivity (HRS), a phenomenon observed at low doses of radiation (<1 Gy); (b) compare the potentiating effects of single dose radiation (2 Gy) versus the effect of low-dose fractionated radiation (LDFRT; <1 Gy) on Paclitaxel; and (c) understand the molecular mechanism of LDFRT-mediated chemo-potentiating effects, in wild-type p53 SCC-61 and p53 mutant SQ-20B head and neck squamous cell carcinoma cell lines. Both cell lines exhibited the HRS phenomenon at low radiation doses. Compared with SCC-61 cells, SQ-20B cells were resistant to radiation and Paclitaxel alone. A significant enhancement of radiation sensitization by Paclitaxel (0.5 or 1 nM) was observed in both cell lines. Chemo-potentiation of Paclitaxel by single 2-Gy radiation was observed in SCC-61 cells but not in SQ-20B cells. However, LDFRT (0.5 Gy in four fractions) significantly chemo-potentiated the effect of Paclitaxel in both cell lines. The cell cycle regulator p53 and its target genes p21(waf1/cip1) and BAX were induced in SCC-61 cells treated with 2 Gy, Paclitaxel, or in combination, but not in SQ-20B cells. These treatments elevated the antiapoptotic BCL-2 protein in SQ-20B cells but not in SCC-61 cells. Interestingly, LDFRT treatment in both cell lines with or without Paclitaxel down-regulated nuclear factor kappa B activity and BCL-2 protein expression and simultaneously up-regulated BAX protein. These findings strongly suggest that LDFRT (at these doses, HRS phenomenon is observed) can be used in combination with Paclitaxel to overcome the antiapoptotic effects of BCL-2 and nuclear factor kappa B.
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PMID:Low-dose fractionated radiation potentiates the effects of Paclitaxel in wild-type and mutant p53 head and neck tumor cell lines. 1268 32

We performed methylation specific PCR to explore the mechanism of inactivation of tumor suppressor genes P15, P16, P53 and VHL in 48 oral SCC. The frequencies of aberrant methylation on the promoter of the P15, the P16, the P53 and the VHL genes were 0.27 (13/48), 0.42 (20/48), 0.04 (2/48) and none, respectively. Altogether, over 50% of the samples showed the CpG-island methylation modification in at least one of the three tumor suppressor genes, indicating that the frequent inactivation of these genes may be an important step during oral cancer development, and the methylation inactivation of P15 or P16 may occur at pre-cancerous stage.
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PMID:Epigenetic changes of tumor suppressor genes, P15, P16, VHL and P53 in oral cancer. 1268 40

Cutaneous squamous cell carcinoma is typically characterized by the over-expression of the tumour suppressor protein p53. Considerable evidence suggests that immune competence is important in the control of cutaneous SCC. We discuss the immunobiology of p53 and its relevance to cutaneous SCC, including the potential interaction with human papillomavirus.
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PMID:The role of p53 in the immunobiology of cutaneous squamous cell carcinoma. 1278 Jun 82

Actinic keratoses are defined as proliferation of cytologically atypical keratinocytes in the zone of epidermal-dermal junction in photodamaged skin. In the northern hemisphere the prevalence of actinic keratoses ranges depending on different epidemiological studies from 11% to 25% for people aged 40 or older. The main cause of actinic keratoses is exposure to UVB radiation in sunlight UVB radiation induces mutations in the telomerase gene and in the tumor suppressor gene P53, which can also be detected in invasive squamous cell carcinoma. The only histological parameter to distinguish between actinic keratoses and SCC is the level of invasiveness. The risk for actinic keratoses to develop into SCC is about 16% over lo years. For this reason and because of the high prevalence of actinic keratoses, it has been suggested to replace the term,, actinic keratosis K with intraepidermal squamous cell carcinoma' to better characterize the lesion. In the following review recent aspects of pathogenesis and therapy of actinic keratoses are discussed.
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PMID:[Actinic keratoses]. 1285 53

There are over 1 million cases of skin cancer diagnosed yearly in the United States. The majority of these are nonmelanoma (NMSCs) and are associated with chronic exposure to ultraviolet light (UV). Actinic keratosis (AK) has been identified as a precursor for SCC, but not for BCC. AKs are far more common than SCC, making them excellent targets for chemoprevention. Cancer chemoprevention can prevent or delay the occurrence of cancer in high-risk populations using dietary or chemical interventions. We have developed strategies that have rational mechanisms of action and demonstrate activity in preclinical models of skin cancer. Promising agents proceed to phase I-III trials in subjects at high risk of skin cancer. UV light induces molecular signaling pathways and results in specific genetic alterations (i.e., mutation of p53) that are likely critical to skin cancer development. UVB-induced changes serve as a basis for the development of novel agents. Targets include inhibition of polyamine or prostaglandin synthesis, specific retinoid receptors, and components of the Ras and MAP kinase signaling pathways. Agents under study include: epigallocatechin gallate (EGCG), a green tea catechin with antioxidant and sunscreen activity, as well as UVB signal transduction blocking activity; perillyl alcohol, a monoterpene derived from citrus peel that inhibits Ras farnesylation; difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase and polyamines; retinoids that target retinoid X receptors and AP-1 activity; and nonsteroidal anti-inflammatory agents that inhibit cylooxygenase and prostaglandin synthesis. We performed a series of Phase I-II trials in subjects with multiple AK. For example, a phase II randomized trial of topical DFMO reduced AK number, suppressed polyamines, and reduced p53 protein. Our goal is to develop agents for use in combination and/or incorporation into sunscreens to improve chemoprevention efficacy and reduce skin cancer incidence.
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PMID:Skin cancer chemoprevention: strategies to save our skin. 1290 51

Measurements of genomic instability, or identification of genes responsible for instability, may potentially be used as molecular markers to predict disease course and response to therapy. Other possible applications include use of genomic instability measurements, or genes, as tools to screen for primary or recurrent disease. Methodologies for detection of genetic mutations in saliva, blood, and sputum have already been described[61,62]. Brennan et al [63] have described a molecular technique for analyzing histopathologically negative margins and lymph nodes for the presence of p53 gene mutation. This study showed that a positive molecular margin significantly predicted disease recurrence. The recognition that HNSCC is a genetically heterogeneous disease represents a major step toward developing an understanding of its underlying genetic basis. To develop an insight into this genetically heterogeneous disease, investigators must not only focus their efforts on specific head and neck disease sites. Laser-capture microdissection represents a powerful tool for isolating very specific cell populations from tumors [64]. Leethanakul et al[65] performed laser-capture microdissection on oral cavity SCC to construct stage-specific cDNA libraries. Sequencing of 96 clones from each of the six libraries constructed suggested the existence of 132 novel genes, which may play a role in the pathogenesis of HNSCC. The current literature suggests that many individuals diagnosed withHNSCC are genetically predisposed to developing malignancy because of some inherent deficiency of their capacity to maintain their genome in the presence of environmental stressors. Head and neck cancers are highly heterogeneous tumors and exhibit a wide variety of forms of genomic instability. Thus, genomic instability may be viewed as a fundamental force driving head and neck tumorigenesis and evolution. Future study of the specific genetic mechanisms that underlie genomic instability in the HNSCCpatient population is needed. It is only through study of this fundamental force that drives the development of these tumors that clinicians may gain the insight required to develop new diagnostic and therapeutic modalities to benefit the HNSCC patient population as a whole.
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PMID:The role of genomic instability in the pathogenesis of squamous cell carcinoma of the head and neck. 1506 58


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