Of particular relevance to cancer chemotherapy are the transporters P-glycoprotein (Pgp) encoded by multidrug resistance 1 gene, multidrug resistance protein (MRP), and breast cancer resistance protein (BCRP).
Interestingly, the treatment of anticancer drugs to the cells overexpressing E2F1, EZH2, and SUZ12 induced the expression of CD44, KLF4, OCT4, and ABCG2 known as cancer stem cell (CSC)-related genes.
The ATP - binding cassette (ABC) family G2 (ABCG2) transporters are known to produce multidrug resistance (MDR) in cancer, thereby limiting the clinical response to chemotherapy.
Lapatinib can modulate the function of ATP-binding cassette (ABC) transporters (ABCB1 and ABCG2), which are the major mechanism responsible for multidrug resistance (MDR) in cancer.
Taken together, our findings indicate that CCTA-1523 is a potent, selective and reversible modulator of ABCG2 that may offer therapeutic promise for multidrug- resistant malignancies.
However, of the various mechanisms that are involved in conferring resistance, upregulation of drug efflux ATP-binding cassette (ABC) transporters, such as P-glycoprotein (ABCB1), multidrug resistance protein 1 (ABCC1) and ABCG2, has become a major obstacle to cancer chemotherapy and seriously affects the clinical outcome.
Finally, the inhibition of Hh/Gli by CK2α siRNA led to a reduction of a cancer stem cell-like side population that shows higher ABCG2 expression level.
Their specific expression in diverse biological contexts cause different phenotypes: (1) multidrug resistance (MDR) and thus failure of cancer chemotherapy, (2) avoidance of accumulation of carcinogens and prevention of carcinogenesis in healthy tissues, (3) absorption, distribution, metabolization and excretion (ADME) of pharmacological drugs in human patients, (4) protection from environmental toxins in aquatic organisms (multi-xenobiotic resistance, MXR).
Our study demonstrates that PCI29732 inhibits the function of ABCG2 by competitively binding to the ATP-binding site of ABCG2 and enhances the anti-tumor efficacy of substrate chemotherapeutic agents, This findings encourages the development of combinational chemotherapy for the treatment of ABCG2- overexpressing cancer patients.
Upregulation of transcriptional regulation of redox sensing factor Nrf2 leads to the overexpression of drug efflux proteins such as ABCG2 in cancer stem cells and thus results in cancer treatment failure and cancer relapse.
Furthermore, the role of BCRP in light of cancer treatments and the implications for novel therapeutic interventions that take into account renal function are discussed.
While multidrug resistance (MDR) in cancer is well established, little is known about the cellular pathways regulating the expression and trafficking of the MDR efflux transporter like BCRP (ABCG2).
As of now, various CSC functions and marker genes have been identified due to the heterogeneity of cancer, such as aldehyde dehydrogenase (ALDH), the second member of the ABC transporter G-subfamily (ABCG2), activated leukocyte cell adhesion molecule (ALCAM) and CD133.
Resistant cells expressed higher levels of genes coding for cancer stem cell markers (JARID1B, CD271 and Fibronectin) as well as genes involved in drug resistance (ABCG2), cell invasion and promotion of metastasis (MMP-1 and MMP-2).
The side population (SP) analysis has been used to detect the stem-like cancer cell populations based on their high expression of ABCG2 that exports Hoechst-33342 and certain cytotoxic drugs from the cells.