Cancer Science & Research


Characteristics of Redox-Metabolism in Patients with Metastatic Colorectal Cancer: Clinical Significance

Burlaka AP, Gafurov MR, Burlaka AA, Ganusevich II.

Colorectal cancer (CRC) is a heterogeneous disease with a high mortality rate, poor prognosis, high percentage of relapses and metastases. Search for the reliable indicators of CRC development and progression is still necessary for the improvement of long-term results of treatment. Objective of this work was to investigate generation rate of superoxide radicals (SR), nitric oxide (NO) levels, matrix metalloproteinase (MMP) activity, lactofferin (Lf) content, amount of “free” iron, Ki-67 expression levels in tissue of tumors in patients with metastasis of II-III stages (T2-4N0-2M0-1G2-3).

Tumor tissue samples from 51 CRC patients diagnosed with metastatic CRC (mCRC) were investigated. 28 patients had stage II disease (T2-4N0M0G2-3) while 23 – stage III (T2-4N1-2M0-1G2-3). In 100% of cases, tumors of the histological type were verified as intestinal adenocarcinomas of different degrees of differentiation (G2-G3). Levels of Lf, “free” iron were determined by conventional X-band electron paramagnetic resonance (EPR) at T = 77 K. SR generation rate and NO levels in mCRC tissues were determined by spin-trapping EPR (TEMPO-H and diethyldithiocarbamate, Fe-DETC; Sigma, USA). The activity of matrix metalloproteinases MMP-2 and -9 was determined by the method of zymography in a polyacrylamide gel. The determination of the Ki-67 expression level was performed by immunofluorescence.

It is shown that for tumors of patients with regional lesions of the lymph nodes (category N1-2), SR generation rate is 2.8 times higher than those in tumors of patients without regional metastases (category N0). In G3-tumors the SR generation rate is 1.7 times higher as compared to G2-tumors (p <0.05). An inverse correlation is found between the SR generation rate and the level of differentiation (r = -0.61; p <0.05). The activity of MMP-2 and MMP-9 correlates with the SR generation rate and NO level (r = 0.44 ÷ 0.53, p <0.05). A direct correlation was found between the level of Lf in mCRC tissue and the stage of the disease (r = 0.42), the level of “free” iron (r = 0.61) and the inverse correlation with the degree of differentiation of tumors (r = -0.57; p <0.05) was established.

The determined tumor redox metabolism parameters in patients with mCRC can be used to predict the course of the disease.

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