p21WAF1/CIP1 is more effective than p53 in growth suppression of mouse renal carcinoma cell line Renca in vitro and in vivo

Prognostic markers in renal cell carcinoma: A focus on the 'mammalian target of rapamycin' pathway

Objectives

Increased knowledge about the molecular pathways involved in tumorigenesis has led to the discovery of new prognostic molecular markers and development of novel targeted therapies for renal cell carcinoma (RCC). In this review we describe the prognostic markers of RCC and highlight the areas of recent discovery with a focus on the mammalian target of rapamycin (mTOR) pathway.

Methods

We reviewed previous reports, using PubMed with the search terms ‘renal cell carcinoma’, ‘molecular markers’, ‘prognosis’, ‘outcomes’ and ‘mammalian target of rapamycin pathway’ published in the last two decades. We created a library of 100 references and focused on presenting the recent advances in the field.

Results

Growing evidence suggests that mTOR deregulation is associated with many types of human cancer, including RCC. Consequently, temsirolimus and everolimus, which target mTOR, are approved for treating advanced RCC. There is a demand to integrate clinical, pathological and molecular markers into accurate prognostic models to provide patients with the most personalised cancer care possible.

Conclusions

The mTOR pathway is highly implicated in RCC tumorigenesis and progression, and its constituents might represent a promising prognostic tool and target for treating RCC. Combining newly discovered molecular markers with classic clinicopathological prognostics might potentially improve the management of RCC.

Adenovirally mediated p53 overexpression diversely influence the cell cycle of HEp-2 and CAL 27 cell lines upon cisplatin and methotrexate treatment

PURPOSE

p53 gene plays a crucial role in the response to therapy. Since it is inactivated in the majority of human cancers, it is strongly believed that the p53 mutations confer resistance to therapeutics. In this paper we analyzed the influence of two mechanistically diverse antitumor agents--cisplatin and methotrexate on the proliferation and cell cycle of two head and neck squamous cancer cell lines HEp-2 (wild type p53 gene, but HPV 18/E6-inactivated protein) and CAL 27 (mutated p53 gene), along with the influence of adenovirally mediated p53 overexpression in modulation of cisplatin and methoterexate effects, whereby subtoxic vector/compound concentrations were employed.

METHODS

p53 gene was introduced into tumor cells using adenoviral vector (AdCMV-p53). The cell cycle perturbations were measured by two parameter flow cytometry. The expression of p53, p21(WAF1/CIP1) and cyclin B1 proteins was examined using immunocytochemistry and western blot methods.

RESULTS

In CAL 27 cells overexpression of p53 completely abrogated high S phase content observed in methotrexate-treated cells into a G1 and slight G2 arrest, while it sustained G2 arrest of the cells treated with cisplatin, along with the reduction of DNA synthesis and cyclin B1 expression. On the other hand, in HEp-2 cell line p53 overexpression slightly slowed down the progression through S phase in cells treated with methotrexate, decreased the cyclin B1 expression only after 24 h, and failed to sustain the G2 arrest after treatment with cisplatin alone. Instead, it increased the population of S phase cells that were not actively synthesizing DNA, sustained cyclin B1 expression and allowed the G2 cells to progress through mitosis.

CONCLUSIONS

This study demonstrates that adenovirally mediated p53 overexpression at sub-cytotoxic levels enhanced the activity of low doses of cisplatin and methotrexate in HEp-2 and CAL 27 cells through changes in the cell cycle. However, the mechanisms of these effects differ depending on the genetic context and on the chemotherapeutics' modality of action.

Diagnostic and prognostic molecular markers in renal cell carcinoma

PURPOSE

We reviewed the contemporary literature on molecular biomarkers in renal cell carcinoma and their prognostic significance.

MATERIALS AND METHODS

Articles published during 1981 to 2007 in English on renal cell carcinoma were surveyed using the MEDLINE/PubMed database. The subject headings included were genetics, biomarkers, prognosis and risk models of renal cell carcinoma. We present a synthesis of currently known renal cell carcinoma biomarkers at various stages of development and their clinical significance, and prognostic nomograms incorporating biomarkers.

RESULTS

The beneficiary role of biomarkers in renal cell carcinoma is challenged by the relatively low prevalence of the disease. Even if a biomarker for renal cell carcinoma had 100% sensitivity and 99.4% specificity, the positive predictive value of the marker in men older than 65 years would be only 10%. Several biomarkers are being investigated in renal cell carcinoma, of which many relate to pathogenic molecular changes that are currently therapeutic targets. Carbonic anhydrase IX is a von Hippel-Lindau mediated enzyme that is expressed in most renal cell carcinoma cases. High (greater than 85%) expression of this marker indicates favorable prognosis and may predict the response to interleukin-2 therapy. B7-H1 expression in renal cell carcinoma cells/lymphocytes may indicate worse survival, possibly through impaired host antitumor immunity. Prognostic nomograms incorporating clinical variables and molecular markers to refine the prediction of treatment outcomes are in active development and await prospective clinical validation.

CONCLUSIONS

Several renal cell carcinoma molecular markers appear promising to refine the prognosis and prediction of localized, advanced or metastatic renal cell carcinoma. Currently carbonic anhydrase IX is the best studied and promising marker. Prospective, multicenter clinical validation aimed at the practical clinical usefulness of renal cell carcinoma biomarkers is warranted.

Electrogene therapy with p53 of murine sarcomas alone or combined with electrochemotherapy using cisplatin

The aim of our study was to evaluate feasibility and therapeutic potential of electrogene therapy with p53 alone or combined with electrochemotherapy using cisplatin on two murine sarcomas with different p53 status. Antitumor effectiveness of three consecutive electrogene treatments with p53 was more effective in wild-type LPB tumors than mutated SA-1 tumors, resulting in 21.4% of tumor cures in LPB tumors and 12.5% in SA-1 tumors. Pretreatment of tumors with electrogene therapy with p53 enhanced chemosensitivity of both tumor models treated by electrochemotherapy with cisplatin. After only one application of this treatment combination in the LPB tumor model, specific tumor growth delay was prolonged in the combined treatment group compared to electrogene therapy with p53 or electrochemotherapy with cisplatin alone, whereas in SA-1 tumors this treatment combination resulted in 31.6% of cured animals. Results of our study show that electrogene therapy with p53 alone or combined with electrochemotherapy is feasible and effective treatment of tumors. The combination of electrogene therapy and electrochemotherapy after only one application resulted in complete regression of tumors.

Rebamipide inhibits gastric cancer cell growth

Rebamipide is an antiulcer drug used in Japan, Korea, China, Philippines, and other Asian countries for treatment of gastritis and peptic ulcer. Its effect on gastric cancer cell growth and its regulatory mechanisms remain unknown. We examined whether rebamipide affects human gastric cancer cell proliferation and activation of Smad signaling pathway. Gastric cancer (AGS) cells were treated with either (a) medium (control), (b) medium-containing rebamipide (0.5-2 mg/mL), or (c) PD98059+rebamipide. We determined cell proliferation, expression of p21, phosphorylation of ERK2, JNK p38, and Smad2/3, formation of Smad2/3-Smad4 complex, and nuclear translocation of Smad2/3. Rebamipide treatment inhibited AGS cell proliferation and increased p21, Smad2/3 phosphorylation, and Smad2/3-Smad4 complex formation. Rebamipide induced phosphorylation of ERK2 but not JNK or p38. Inactivation of ERK2 by PD98059 partly attenuated rebamipide-induced p21 expression. These data demonstrate that rebamipide activates Smad signaling pathway and suppresses human gastric cancer cell growth. Inactivation of ERK2 partly inhibited rebamipide-induced p21 expression, indicating a crosstalk between ERK and Smad signaling pathways.

Biochemical and molecular markers in renal cell carcinoma: an update and future prospects

Cancer is a big problem in the developed world as well as in developing countries. Renal cell carcinoma (RCC) accounts for approximately 3% of adult malignancies and 90-95% of neoplasms arising from the kidney. RCC is more common in men than in women (2:1), and it most often occurs in patients between the ages of 50-70 years. In all cancers the cancerous cells release particular kind of proteins (called tumour markers) and blood tests are used to detect the presence of these markers. These tumour markers nowadays are an area of interest for oncologists who search for a possible solution in the detection and treatment of RCC. Different kinds of biochemical and molecular markers such as ferritin, MN/CA9, apoptotic index, p53, IL-2, gamma-enolase, CD44, CD95, chromosome instability and loss of heterozygosity have been tested in RCC, but so far no marker fulfils one or the other criteria to be considered as an ideal marker for RCC. This review gives basic and updated information about the different kinds of biomarkers studied in RCC and about the role implementation of genomics and proteomics in RCC.