Design, Synthesis and Evaluation of Substituted N-（3-Arylpropyl）-9,10-dihydro-9-oxoacridine-4-carboxamides as Potent MDR Reversal Agents in Cancer

A novel class of molecules with structure N-（3-arylpropyl）-9,10-dihydro-9-oxoacridine-4-carboxamides （20- 29） were designed by generating a pharmacophore for potent MDR reversal activity using phase drug design software. The designed molecules were synthesized by a novel synthesis route and evaluated for their inhibitory effects on the transport activity of P-glycoprotein （P-gp） by standard Hoechst 33342 assay method. Based on the pIC50 values of ten title compounds screened, three compounds exhibited better activity as compared to Verapamil used as standard.

Multidrug Resistance P-glycoprotein Function of Bone Marrow Hematopoietic Cells and the ReversalAgent Effect

The multidrug resistance P-glycoprotein (P-gp) expression and func-tion in hematopoietic stem/progenitor cells were studied to investigate whether the inhibition of hematopoietic cell P-gp function by multidrug resistance reversal agent increases the cytotoxicity of chemotherapy drugs on the hematopoietic cells.The expression of P-gp on the surface of CD cells from healthy human marrow was examined by flow cytometry. The multidrug resistance reversal agent MS-209 was used to measure the effects of MS-209 on the Rhodamin-123 uptaking o fCD hematopoietic cells. By using methylcellulose semi-solid culture, normal human granulocyte-macrophage clonal formation unit (CFU-GM) was cultured. The changes in CFU-GM inhibitory rate caused by daunorubicin were determined in the presence or absence of MS-2O9. The results showed that the P-gp expression rate of bone marrow CDL cells was 13. 3 %. MS-209 obviously increased the Rhodamin-123 uptake of CD positive cells. The mean inhibitory rate of daunorubicin for CFU-GM was 29. 6 %, but it was increased to 43. 3 % in the presence of MS-209 with the difference being significant (P< 0. 05). It was concluded that hematopoietic cells expressed P-gp protein and possessed active function- MS-209could inhibit the membrane efflux pump and increase the cytotoxicity of chemotherapy drugs to the clonal growth of hematopoeitic stem cells, suggesting the side effects of these drugs on the hematopoietic system should be taken into consideration in the clinical use.

The Rational Combination Strategy of Immunomodulatory Latency Reversing Agents and Novel Immunotherapy to Achieve HIV-1 Cure

Human immunodeficiency virus(HIV)-1 infection creates a persistent latent reservoir even after antiretroviral therapy,which is the main barrier to HIV cure.One of the most explored strategies is the use of latent reversal agents(LRAs)to activate HIV latent reservoirs,followed by immunotherapy to remove infected cells.Immunomodulatory LRAs have the dual advantage of activating viral latency and promoting immune cell elimination of HIV-infected cells.The emergence of novel immunotherapies has also enhanced the possibility ofHIV clearance.Here we review the activity and potential mechanisms of immunomodulatory agonists and immunotherapies.The possible combinational strategies to achieve HIV functional cure and the problems encountered using this approach are discussed.

Research Progress on Reversing Multidrug Resistance in Tumors by Using Chinese Medicine

Multidrug resistance （MDR） is a major cause of cancer chemotherapy failure, and it is important to develop suitable reversal agents to overcome MDR. A majority of chemical reversal agents have acceptable reversal effects. However, the toxicity and adverse reactions associated with these agents restricts their clinical use. Chinese medicines （CMs） have lower toxicities and adverse reactions and are associated with multiple components, multiple targets and reduced toxicity. CMs have several advantages and could reverse MDR, decrease drug dosage, enhance patient compliance and increase efficacy. This review summarizes the current progress of CM reversal agents..

MET inhibitor tepotinib antagonizes multidrug resistance mediated by ABCG2 transporter:In vitro and in vivo study

Overexpression of ABCG2 transporter in cancer cells has been linked to the development of multidrug resistance(MDR), an obstacle to cancer therapy. Our recent study uncovered that the MET inhibitor,tepotinib, is a potent reversal agent for ABCB1-mediated MDR. In the present study, we reported for the first time that the MET inhibitor tepotinib can also reverse ABCG2-mediated MDR in vitro and in vivo by directly binding to the drug-binding site of ABCG2 and reversibly inhibiting ABCG2 drug efflux activity, therefore enhancing the cytotoxicity of substrate drugs in drug-resistant cancer cells. Furthermore, the ABCB1/ABCG2 double-transfected cell model and ABCG2 gene knockout cell model demonstrated that tepotinib specifically inhibits the two MDR transporters. In mice bearing drug-resistant tumors, tepotinib increased the intratumoral accumulation of ABCG2 substrate drug topotecan and enhanced its antitumor effect. Therefore, our study provides a new potential of repositioning tepotinib as an ABCG2 inhibitor and combining tepotinib with substrate drugs to antagonize ABCG2-mediated MDR.

Advances in HIV Eradication Strategies

Although the advent of combination antiretroviral therapy can efficiently suppress human immunodeficiency virus(HIV)replication,a complete cure for HIV infection cannot be achieved due to the existence of latent viral reservoirs.In recent years,investigation of HIV cure strategies has become a hot topic in the field.In this article,we review the major barriers to HIV cure,compare the progress and challenges of non-specific and specific latent reversal agents in curing HIV,and discuss possible solutions to the current problems.