Modulation of P-Glycoprotein activity is a strategy aimed at overcoming chemoresistance in cancer cells. Chemoresistance is a significant obstacle to successful cancer therapy, as it limits the efficacy of many anticancer agents. P-Glycoprotein, an ATP-binding cassette transporter, is one of the major factors contributing to multidrug resistance in cancer cells. Modulating its activity, either through pharmacological inhibitors or molecular targeting, has been shown to sensitize cancer cells to anticancer agents and improve the effectiveness of cancer therapy. ABCB1 and ABCG2 are two major P-Glycoprotein isoforms that have been targeted for modulation in cancer treatment. Moreover, the tumor microenvironment has been shown to play a critical role in regulating P-Glycoprotein expression and activity, and targeting this aspect of the tumor microenvironment may also improve cancer therapy outcomes. Overall, Modulation of P-Glycoprotein activity represents a promising approach for overcoming drug resistance and improving cancer therapy efficacy.

P-Glycoprotein is an efflux pump that transports drugs out of cancer cells, thereby reducing their intracellular concentrations and preventing their cytotoxic effects. Modulating P-Glycoprotein activity can be achieved through different mechanisms, such as inhibiting its function or decreasing its expression at the transcriptional or post-transcriptional level. Several pharmacological inhibitors of P-Glycoprotein have been developed, including verapamil, cyclosporine A, and tariquidar, among others. However, their clinical use has been limited due to their toxicity and off-target effects. Alternatively, molecular targeting of P-Glycoprotein using RNA interference or small molecule inhibitors that selectively bind to P-Glycoprotein may provide a more specific and safer approach.

Moreover, recent studies have highlighted the role of P-Glycoprotein in regulating the immune response in the tumor microenvironment, suggesting that modulating its activity may also impact the efficacy of immunotherapy. Furthermore, the role of P-Glycoprotein in cancer stem cells has also been investigated, as these cells are often responsible for chemoresistance and tumor recurrence. Therefore, targeting P-Glycoprotein in cancer stem cells may represent an additional approach to overcome drug resistance.

Chemoresistance is the resistance of tumor cells to broad spectrum of chemotherapeutic agents and

is one of the major obstacles in the treatment of human cancers .

This phenomenon of occurrence of multiple drug resistance/MDR is described by the cross resistance

to many drugs, which are unrelated, and whose structures and/or mechanisms of action may be

completely different. MDR often appears during cancer chemotherapy or during recurrence after

chemotherapy . The cancer cells can acquire resistance through

several mechanisms, which include overexpression of ABC transporters, enhanced DNA

damage response, aldehyde dehydrogenase (ALDH) activity, activation of key signaling pathways and

B- cell lymphoma-2 (BCL2) related chemoresistance .

There are 48 ATP binding cassette superfamily proteins reported in human beings. These

proteins are usually expressed in the cellular membranes and serve to transport the

materials.