Determination of cytosolic citrulline and nitrate as indicators of nitric oxide in bladder cancer: possible association with basic fibroblast growth factor

Gasotransmitters in the tumor microenvironment: Impacts on cancer chemotherapy (Review)

Nitric oxide, carbon monoxide and hydrogen sulfide are three endogenous gasotransmitters that serve a role in regulating normal and pathological cellular activities. They can stimulate or inhibit cancer cell proliferation and invasion, as well as interfere with cancer cell responses to drug treatments. Understanding the molecular pathways governing the interactions between these gases and the tumor microenvironment can be utilized for the identification of a novel technique to disrupt cancer cell interactions and may contribute to the conception of effective and safe cancer therapy strategies. The present review discusses the effects of these gases in modulating the action of chemotherapies, as well as prospective pharmacological and therapeutic interfering approaches. A deeper knowledge of the mechanisms that underpin the cellular and pharmacological effects, as well as interactions, of each of the three gases could pave the way for therapeutic treatments and translational research.

Can the levels of nitric oxide in the urine, serum and tumor tissue be putative markers for bladder cancer?

AIM

To determine nitric oxide (NO) levels in serum, urine, tumor tissue and non-malignant adjacent tissue in bladder cancer patients compared with those in patients with a non-neoplastic genitourinary disease and to evaluate postoperative serum and urine NO change.

METHODS

Samples was collected in 20 cancer and 41 control patients. Griess reagent was used for NO measurements.

RESULTS

Mean age in the cancer and control groups was 64.2 +/- 9.9 and 63.7 +/- 8.9 years, respectively. Preoperatively, urinary infection incidence was not statistically different between groups. There were no significant differences in serum, urine and tissue NO levels in patients with and without infection in both groups. Hematuria was found to not affect urine NO level in the cancer group. Urine NO level was significantly higher than in controls preoperatively, decreased significantly following operation and remained stable after the third month. High serum NO values decreased at the early postoperative period; however, they re-increased in the long-term. No significant differences were observed in the third month in serum and urine NO levels between the patients with (no. 6) and without (no. 14) residual or relapsing tumor. No statistical difference was observed between NO levels in non-malignant adjacent and control tissues. However, tumor tissue NO level was significantly higher than those in the other two. There were no statistical differences in the first and third month serum and urine NO levels between patients who underwent bacillus Calmette-Guérin instillation therapy postoperatively and the patients who took chemotherapy or no further treatment.

CONCLUSIONS

Both local and generalized host defense mechanisms seem to function in bladder cancer patients. Although further evaluation with a longer observation period and larger numbers of patients is necessary, results suggest that serum and urine NO levels are not putative and useful markers for bladder cancer.

Methylguanine DNA methyl transferase activities, glutathione s transferase and nitric oxide in bladder cancer patients

Tumor formation is a multistep process that can be divided in to the stages of tumor initiation, promotion, and progression. DNA repair protein; MGMT is a key suicide enzyme that repairs the mispairing base methylguanine, which is induced in DNA as a minor lesion. The glutathione S transferases (GSTs) are a family of enzymes that are important to protect against alkylating agents. Nitric oxide, contributes to the regulation of tumor angiogenesis. A substantial body of experimental evidence supports the hypothesis that tumor angiogenesis is fundamental for the growth and metastasis of solid tumors. We measured the activities of GST, MGMT, and levels of NO3-/NO2- in the leukocytes from patients with bladder carcinoma and healthy controls and activities of MGMT in the tissue from patients with bladder carcinoma and adjacent normal tissue in bladder. Both GST and tissue MGMT activites were significantly increased in the patient group. There was no significant difference between controls and patients for MGMT activity in peripheral blood leukocytes (PBL). Nitrate/nitrite levels in PBL, there was no significant difference between controls and patients. Nitrate/nitrite levels were increased in G2-G3 tumors. In conclusion, we determined high concentrations of nitrite in leukocytes are suspected alkylation damage by induction nitrosamine. Increased DNA alkylation damage may lead the stimulation of MGMT and GST.

Angiogenesis in bladder cancer--prognostic marker and target for future therapy

Angiogenesis is the process by which tumours induce a blood supply, crucial for growth and metastasis. Evidence for its role in bladder carcinogenesis, its usefulness as a marker of patient prognosis, and potential anti-angiogenic therapies for future development are discussed in this chapter.