The effect on MİP2 and KC release of the autocrine factors released by mammary carcinoma cell lines, C3a, UPA AND TSLP.

Purpose:Today, breast cancer is the most common malignancy with it's substantial mortality. Neverthless, there is no approach that prevents or reverses the metastatic spread, which is held responsible for its mortality.On the other hand, the advanced complexity of "cancer" causes necessity for the approaches in the field of molecular mechanisms in targeted and integrated manners.CXC chemokines and their receptors represent a molecular system that has been proven to play an important role in cancer development and progression.In addition, it has been demonstrated that particularly CXCR2 is expressed by various cancer cells and it's activation is crucial for development of metastasis. Therefore, CXCR2 antagonists seem to be promising as anti-cancer therapy and clinical trials are ongoing in that field. It has been demonstrated that KC and MIP2, which are ligands for CXCR2, play substantal roles in tumorigenesis by causing CXCR2 activation.These chemokines have also been found to be involved in metastasis, with released by metastatic mouse breast cancer cell lines in higher levels compared to nonmetastatic ones. Background: Our previous studies have shown that the CXCR2 antagonist SB225002 provides anti-tumorigenic effect while increases the levels of MIP2 and KC released into the tumor microenvironment. That condition revealed that CXCR2 is an autoreceptor for these ligands and indicated that long term use of antagonist may be cause chemoristance . Moreover, MIP2 release had an increasing kinetics time dependently.This suggests that various autocrine factors released by metastatic cells may be one of the mechanisms responsible for possible chemoresistance by increasing the release of CXCR2 ligands.Additionally, in our preliminary study, it is found that 85 released autocrine factors into the conditioned medium by metastatic cells, which significantly differ compared to nonmetastatic cells. In our study, we evaluated three of these proteins which is known with increasing the release of KC and/or MIP2 or activate the intracellular survival pathways, such as the PI3K /Akt that have substantial roles in release of that chemokines, but have not been examined in cancer cells before, by evaluating the effects of their antagonists.These proteins are; Plasminogen Activator, Urokinase (uPA), Complement Component 3a (C3a) and Thymic Stromal-Lymphopoietin (TSLP). Matherial and Methods:Levels of these proteins released by 4T1, 4THM, 4TBM and 4TLM metastatic murine mammary carcinoma and nonmetastatic 67NR cells were determined by ELISA. The effects of these proteins' spesific antagonists on cell proliferation were evaluated with WST-1 kit, on 4THM and 4TBM cells, whose MIP2 release are known as higher and consistent,.Changes in MIP2 and KC levels were measured by ELISA. To evaluate whether the changes in the chemokine release caused by antagonists are consistent with their effects on the PI3K/Akt, Erk1/2 and p38-MAPK pathways, phosphorylated Akt, Erk and p38 levels were determined by immunoblot technique. Results:uPA, C3a and TSLP were measured in all cells at different levels according to cell type. uPa antagonistIPR-803 decreased chemokine release while suppressing the proliferation of metastatic cells, and this effect was corraleted with the inhibition of Akt, Erk and p38 phosphorylation. Moreover, when it was combinated with CXCR2 antagonist SB225002, uPA receptor blockade increased the antiproliferative effect of SB225002 and reversed it's increasing effect on chemokine levels. C3a antagonist SB290157 exhibited restricted suppression on cell proliferation.Moreever, it is demostrated that C3a increases MIP2 levels in the cancer cells on that was examined of MIP2 release caused by C3a for the first time. TSLP was determined at a high levels in all metastatic cells. On the other hand, while TSLPR-Ig suppressed Akt, Erk and p38 phosphorylation, increased the proliferation of 4TBM cells. Also it showed an inconsistent effect on chemokine release. Conclusion:The uPA-uPAR axis appears to be a suitable target in breast cancer in order to prevent "authoresistance", which can be caused by autocrine mechanism in long-term treatment with CXCR2 antagonists, which are promising as adjuvant agents in cancer treatment, in addition to the antitumor effect directly provided by it's antagonism.