MULTI TARGET DIRECTED LIGANDS (MTDLs) AS POTENTIAL THERAPIES FOR BLADDER CANCER

Abstract

Bladder cancer is the predominant type of cancer affecting males. It is also a malignancy that targets females as well. Recent studies implicated a sub-population of tumor cells with stem cell properties in imparting resistance to chemotherapy and radiation. Henceforth, it is critical to distinguish and explicitly target those cancer stem cells. Significantly, multiple inflammatory cascades are involved in the pathogenesis of proliferative disorders, namely the Arachidonic acid (AA) pathway involving cyclooxygenase-2 (COX-2) and 15-lipoxygenase (15-LOX). They assume a multitude of functions ranging from metabolic impairment leading to adipose tissue inflammation, to pro- and anti- tumorigenic effects making them viable targets for interference with tumor growth. However, such an intervention is often complicated by the uniqueness and often mutual regulatory effects of COX-2 and 15-LOX on different cellular targets mainly the Peroxisome Proliferator-Activated Receptor (PPARγ).

Hypothesis & Aim Treating bladder cancer as a multifaceted disorder requires the regulation of more than one target. We hypothesize that the simultaneous targeting of COX-2, 15-LOX and PPARγ by MTDLs will be effective in suppressing human bladder cancer cell growth.

Methods Two Human bladder cancer cell lines (RT4 & T24) will be treated with different concentrations of MTDL inhibitors of COX-2 & 15-LOX with or without PPARγ partial agonist activity. MTT and Trypan blue exclusion assays will be used to assess the anti-proliferative effect of these compounds in vitro. In addition, the ability of these drugs to inhibit cell migration will be tested using the wound-healing migration assay. Moreover, the 3D sphere-formation assay will be used to investigate their impact on the cancer stem/progenitor cells population in both cell lines. Molecular studies will also be performed to assess the potential mechanism involved.

Results Treatment with MTDLs namely Pd3 was shown to decrease RT4 & T24 cell proliferation and migration as well as inhibit sphere-formation ability in a dose-dependent manner. Moreover, Pd3 was able to inhibit Monocyte differentiation into macrophages which, occurs during inflammation thus, is effective in targeting inflammation induced cancer. Molecular studies showed that the dual target drug was able to target inflammatory pathways involved in the pathogenesis of cancer. This is the first study to assess the effect of double- and triple-target drugs on human bladder cancer cells in vitro and possibly demonstrate their potential therapeutic value.