High P2X6 receptor expression in human bladder cancer predicts good survival prognosis.

As alterations in purinergic signaling have been observed in bladder diseases, we aimed to assess the potential prognostic role of purinergic receptors in bladder cancer in a translational approach based on clinical databases and in vitro data. The prognostic role of purinergic receptors in the survival of patients with bladder cancer and the expression profile of the altered P2 receptors in normal and in tumor samples were determined using The Cancer Genome Atlas databank. In T24 and RT4 human bladder cancer cell lines, the P2 purinergic receptors were characterized by RT-PCR and RT-qPCR analysis including radiotherapy exposure as treatment. The cell number and the cumulative population doubling were also assessed. The expression profile of P2X6 receptor in the cancer pathological stage and in the nodal metastasis status was in agreement with Kaplan-Meier analysis, indicating that high expression of this receptor was related to an increased survival rate in patients with bladder cancer. Of all the P2 receptors expressed on T24 cell line, P2X6 presented high expression after radiotherapy, while it was not altered in RT4 cells. In addition, irradiation promoted a decrease of T24 cell number, but did not change the cell number of RT4 after the same time and radiation dose. Along 7 days after irradiation exposure, both cells regrew. However, while P2X6 receptor was downregulated in T24 cells, it was upregulated in RT4 cells. Our findings indicated that high P2X6 receptor expression induced by radiation in T24 cell line may predict a good survival prognostic factor.

AMP hydrolysis reduction in blood plasma of breast cancer elderly patients after different treatments.

Adenine nucleotides are important signaling molecules that mediate biological functions in many conditions, including cancer. The enzymes CD39 and CD73 produce adenosine in the extracellular milieu that has a very important role in tumor development. This study aimed to evaluate nucleotide hydrolysis in the plasma blood of breast cancer elderly patients. In this prospective cohort study, we investigated the ectonucleotidases activity in breast cancer elderly patients, at the moment of diagnosis and after treatment. Control group consisted of elderly women without cancer diagnostic. The nucleotide hydrolysis assay was performed by the malachite green method and used ATP, ADP, or AMP as substrates. Paired t test or Wilcoxon rank-sum test was used. Our data showed that breast cancer patients presented high levels of ATP and AMP hydrolyses when compared to control group at the moment of diagnosis. When analyzing the differences between the samples at the time of diagnostic and 6 months after treatment, we observed a significant reduction on CD73 activity after all treatments used: surgery, chemotherapy, radiotherapy, or hormone therapy. The results with APCP, a specific CD73 inhibitor, showed that the AMP hydrolysis was inhibited in all conditions evaluated. We observed a diminished ADPase activity in the patients without metastasis when compared to metastatic breast cancer patients. The results showed that AMP hydrolysis was reduced in the blood plasma of breast cancer elderly patients after different treatments. This study strengthens the potential role of CD73 enzyme as a biomarker for breast cancer treatment response.

Hydrolysis of ATP, ADP, and AMP is increased in blood plasma of prostate cancer patients.

Prostate cancer is among the major malignancies that affect men around the world. Adenine nucleotides are important signaling molecules that mediate innumerous biological functions in pathophysiological conditions, including cancer. These molecules are degraded by several ectoenzymes named ectonucleotidases that produce adenosine in the extracellular medium. Some of these ecto-enzymes can be found in soluble in the blood stream. Thus, the present study aimed to evaluate the hydrolysis of adenine nucleotides (ATP, ADP, and AMP) in the plasma blood of patients with prostate cancer. Peripheral blood samples were collected, and questionnaires were filled based on the clinical data of the medical records. The nucleotide hydrolysis was performed by Malachite Green method using ATP, ADP, and AMP as substrates. Plasma from prostate cancer patients presented an elevated hydrolysis of all nucleotides evaluated when compared to healthy individuals. NTPDase inhibitor (ARL67156) and the alkaline phosphatase inhibitor (levamisole) did not alter ATP hydrolysis. However, AMP hydrolysis was reduced by the CD73 inhibitor, APCP, and by levamisole, suggesting the action of a soluble form of CD73 and alkaline phosphatase. On microvesicles, it was observed that there was a low expression and activity of CD39 and almost absent of CD73. The correlation of ATP, ADP, and AMP hydrolysis with clinic pathological data demonstrated that patients who received radiotherapy showed a higher AMP hydrolysis than those who did not, and patients with lower clinical stage (CS-IIA) presented an elevated ATP hydrolysis when compared to those with more advanced clinical stages (CS-IIB and CS-III). Patients of all clinical stages presented an elevated AMPase activity. Therefore, we can suggest that the nucleotide hydrolysis might be attributed to soluble ecto-enzymes present in the plasma, which, in a coordinate manner, produce adenosine in the blood stream, favoring prostate cancer progression.