TDK conference 2011

Mammary tumours are among the most common neoplastic process in female dogs. The purpose of our research is to detect some important proteins at the level of the RNA in malignant tumours, in healthy mammary gland, and some other tumours. Based on literature data we can say that the tendency of metatstatic breast cancer is heavily influenced by the tested proteins, and the confirmation of their persence insures the possibility of targeted anti-cancer treatment. The researched proteins were the following: MDR-1, MRP-1, ABCGC-2, VEGF, COX-1, COX-2.

MDR-1, MRP-1 and ABCGC-2 are multiresistence proteins. Due to their broad substrate specificity they play a major role in the accessibility of biological regulation of drugs. Besides their physiological role they have a great importance in the development of resistence against the cytotoxic medications in tumour cells. Their prognostic value is already known in tumours of different origin, as they pump the chemotherapy drugs out of the cells, so that they reduce the efficiency of anti-tumour therapy.

COX-1, COX-2, and VEGF proteins are heavily expressed in several tumour tissues. The COX isoenzymes reduce the development of apoptosis, thus facilitating uncontrolled tumour growth. They also reduce the sensitivity of the cells agains the growth-inhibiting signal transduction mechanisms, and they help the invasivity and the metastatic propansivity of the tumour cells. VEGF induces the creation of new blood vessels, stimulates the production of collagenase and other „degrading” enzymes, thereby accelerating the access of cancer cells into a blood vessel, and stimulates tumour cell growth.

We collected our samples in the Veterinary Haematology and Oncology Centre. In case of dogs suffering in tumour, we took samples from the mammary gland that showed neoplastic mutation and from the healthy one, also. We removed the mammary glands of dogs having tumour by surgical way. We isolated the nucleic acids using TRIZOLŸ reagent, then we assigned the relative expression of mRNA level of the proteins using RT-qPCR.

Based on the samples already processed we can say that the mRNA level of multidrog resistence proteins was higher in mammary glands showing neoplastic mutation than in healthy ones. It seems that the amount of proteins, according to their role in tumour cells, already increases as a consequence of malignant transformation. The amount of COX-1, COX-2 and VEGF proteins is typifying the definite tumour. Beyond the clinicopathological parameters, the definition of the quantity of these proteins can be helpful in cognition of the special characteristics of tumours and in planning the convenient treatment.

This work was supported by the NCB