Due to the importance of arginase enzyme in different malignant disorders, the purpose ofthe present study was to determine and compare the arginase activity in cancerous cells andtheir normal and benign counterparts. The tissue arginase activity level was evaluated in 30females with breast cancer, in 6 females with benign breast disease and in 9 healthy controlsubjects. The arginase activity levels were significantly increased in malignant breast tissues incomparison to healthy ones, while the difference did not reach the level of significance incomparison to benign breast diseased tissues. Patients with advanced stage showedinsignificantly higher arginase activity compared to those with early stage. In addition,estrogen receptor negative tumors showed insignificant higher arginase activ6ity levelscompared to estrogen receptor positive tumors. Moreover, tissues of premenopausal patientsshowed lower activity levels of arginase compared with those of postmenopausalones.Meanwhile, patients with bad prognosis revealed insignificantly higher activity levels ofarginase compared to those with good prognosis. It could be concluded that tissue arginaseactivity seems to be involved in the biological behaviour of breast cancer and its determinationin cancerous tissues could predict its outcome.

Recent developments in the literature have demonstrated that curcumin exhibit antioxidant properties supporting its anti-inflammatory, chemopreventive and antitumoral activities against aggressive and recurrent cancers. Despite the valuable findings of curcumin against different cancer cells, the clinical use of curcumin in cancer treatment is limited due to its extremely low aqueous solubility and instability, which lead to poor in vivo bioavailability and limited therapeutic effects. We therefore focused in the present study to evaluate the anti-tumor potential of curcumin analogues on the human breast carcinoma cell lines MDA-MB-231 and MCF-7, as well as their effects on non-tumorigenic normal breast epithelial cells (MCF-10). The IC₅₀ values of curcumin analogue J1 in these cancer cell lines were determined to be 5 ng/ml and 10 ng/ml, in MDA-MB-231 and MCF-7 cells respectively. Interestingly, at these concentrations, the J1 did not affect the viability of non-tumorigenic normal breast epithelial cells MCF-10. Furthermore, we found that J1 strongly induced growth arrest of these cancer cells by modulating the mitochondrial membrane potentials without significant effect on normal MCF-10 cells using JC-1 staining and flow cytometry analysis. Using annexin-V/PI double staining assay followed by flow cytometry analysis, we found that J1 robustly enhanced the induction of apoptosis by increasing the activity of caspases in MDA-MB-231 and MCF-7 cancer cells. In addition, treatment of breast cancer cells with J1 revealed that, in contrast to the expression of cyclin B1, this curcumin analogue vigorously decreased the expression of cyclin A, CDK2 and cyclin E and subsequently sensitized tumor cells to cell cycle arrest. Most importantly, the phosphorylation of AKT, mTOR and PKC-theta in J1-treated cancer cells was markedly decreased and hence affecting the survival of these cancer cells. Most interestingly, J1-treated cancer cells exhibited a significant inhibition in the activation of RhoA followed by reduction in actin polymerization and cytoskeletal rearrangement in response to CXCL12. Our data reveal the therapeutic potential of the curcumin analogue J1 and the underlying mechanisms to fight breast cancer cells.