Four-drug combination chemotherapy in advanced lung cancer: methotrexate, doxorubicin, cyclophosphamide and CCNU

TAp63 plays compensatory roles in p53-deficient cancer cells under genotoxic stress

p53, p63, and p73 belong to the p53 family of proteins, which mediate development, differentiation, and various other cellular responses. p53 is involved in many anti-cancer mechanisms, such as cell cycle regulation, apoptosis, and the maintenance of genomic integrity. The p63 gene is controlled by two promoters that direct the expression of two isoforms, one with and one without transactivating properties, known as TAp63 and ΔNp63. In this study, p53-deficient cells (Hep3B and PC-3) and p53-expressing cells (A549 and HepG2) were treated with doxorubicin to examine the possible roles of TAp63 in these cells under genotoxic stress; TAp63 expression was induced in p53-deficient cell lines, but not in p53-expressing cell lines. The ectopic expression of p53 in p53-deficient cells (Hep3B) reduced TAp63 promoter activity, and knockdown of TAp63 attenuated doxorubicin-induced cell growth arrest by promoting cell cycle progression, leading to an increase in the percentage of G(2)/M cells. Moreover, knockdown of TAp63 increased cell sensitivity to doxorubicin-induced genomic damage. Our results suggest that TAp63 may play a compensatory role in cell cycle regulation and DNA damage repair in p53-deficient cancer cells.

Transcriptional activity of TAp63 promoter is regulated by c-jun

The transcription factor p63 belongs to the p53 protein family and plays an important role in epithelial development. Recent studies showed that p63 is over-expressed in some human squamous cell carcinomas of the head and neck, suggesting a role in carcinogenesis. The p63 gene contains two promoters and alternative promoter usage generates two groups of proteins with (TAp63) or without (ΔNp63) the transactivation domain. Although the roles of TAp63 in epithelial development have been described in numerous recent studies, the regulation of its expression has not been elucidated. In this study, we showed that the transcriptional activity of the TAp63 promoter and TAp63 protein level were both up-regulated by an increased c-jun activity in Hep3B human hepatocellular carcinoma cell. Moreover, the elevated TAp63 expression was coincided with an increased binding of c-jun to the TAp63 promoter. Point mutation of the sp1 binding site within the TAp63 promoter region attenuated the effect of c-jun on TAp63 expression. Knockdown of TAp63 expression by shRNA led to increased proliferation of Hep3B cell compared to that of the mock cell, suggesting a growth suppressive effect of TAp63.

Chemotherapy in advanced non-small cell lung cancer

Chemotherapy in advanced non-small cell lung cancer (NSCLC) has been evaluated with response rate, survival and quality of life as criteria. The data were collected from 142 phase II and III trials. The three main conclusions are: (1) multivariate landmark analyses show that a response to chemotherapy has an independent significant value for prognosis, and all studies of chemotherapy vs. best supportive care show some survival benefit in favour of chemotherapy; (2) NSCLC patients are a heterogeneous group with a large variation of known and unknown prognostic factors, such as the treatment centre, for both response and survival; and (3) retrospective analysis of the data show that response rate and survival are significantly correlated at response rate over 30% and in limited disease patients. The following recommendations are made: (1) new drugs should be compared in randomised phase II trials with a standard active drug; (2) randomised phase III trials of single agents or best supportive care vs. combination chemotherapy should be repeated in a well-defined subgroup of patients with a high performance score and limited tumour load; and (3) the palliative effect of chemotherapy in randomised trials in patients with symptoms should be investigated with relief of symptoms and quality of life as endpoints.

CAMP chemotherapy for metastatic non-oat cell bronchogenic carcinoma. A 7-year experience (1975-1981) with 160 patients

Between January 1975 and December 1981, 160 patients with metastatic non-oat cell bronchogenic carcinoma (MNOBC) were treated with cyclophosphamide, doxorubicin, methotrexate, and procarbazine (CAMP), or with a CAMP-like regimen. Forty-two (26%) of these patients demonstrated an objective response to the chemotherapy with a median survival of 61 weeks. Thirty-nine (24%) patients had stable disease (SD) with a median survival of 45 weeks. Seventy-nine patients (49.4%) were nonresponders with a median survival of 15 weeks. There was a significant difference in survival times between the responders and the SD patients, and between the responders and SD patients and the nonresponders. Responses were seen in 11% of the patients with squamous cell carcinoma and in 37% of the patients with adenocarcinoma. There was a significant difference in the response and SD categories in favor of adenocarcinoma over squamous cell carcinoma. Once a response was achieved, the median survival of the patients with adenocarcinoma was not significantly longer than that of the patients with squamous cell carcinoma.