Reversal effect of FW-04-806, a macrolide dilactone compound, on multidrug resistance mediated by ABCB1 and ABCG2 in vitro and in vivo

Phenylspirodrimane with Moderate Reversal Effect of Multidrug Resistance Isolated from the Deep-Sea Fungus Stachybotrys sp. 3A00409

Two new phenylspirodrimanes, stachybotrins K and L (1 and 2), together with eight known analogues (3-10), were isolated from deep-sea-derived Stachybotrys sp. MCCC 3A00409. Their structures were determined by extensive NMR data and mass spectroscopic analysis. Absolute configurations of new compounds were determined through a comparison of their circular dichroism (CD) spectra with other reported compounds. The possible reversal effects of all compounds were assayed in the resistant cancer cell lines. Stachybotrysin B (8) can reverse multidrug resistance (MDR) in ABCB1-overexpression cells (KBv200, Hela/VCR) at the non-cytotoxic concentration. Doxorubicin accumulation assay and molecular-docking analysis reveal that the mechanism of its reversal MDR effect may be related to the increase in the intracellular concentration of substrate anticancer drugs.

Screening Multidrug Resistance Reversal Agents in Traditional Chinese Medicines by Efflux Kinetics of D-Luciferin in MCF-7/DOXFluc Cells

In this study, we established a simple and rapid in vitro method for screening multidrug resistance (MDR) reversal agents in traditional Chinese medicines (TCMs), which could better correspond to the MDR reversing effect in vivo. Here, D-luciferin, a substrate for the enzyme firefly luciferase and also a substrate for ATP-binding cassette transporters (ABC transporters), was used as the probe to detect its efflux kinetics caused by ABC transporters. First, we established a stable doxorubicin (DOX)-resistant cell line (MCF-7/DOX^Fluc) that overexpressed luciferase. Then, some kinds of TCMs were chosen for the MDR reversal agents to measure its effect on inhibiting the D-luciferin outflow from MCF-7/DOX^Fluc, and the ideal reversal agent with the least D-luciferin efflux from MCF-7/DOX^Fluc was selected to further investigate its effect combined with DOX on MCF-7/DOX^Fluc tumor-bearing mice. The results indicated that quercetin (Qu) could remarkably increase the retention of D-luciferin in MCF-7/DOX^Fluc in vitro and in vivo. Also, the combination of Qu and DOX could exceedingly inhibit the tumor growth, which proved the feasibility of this in vitro screening method. The study proposed a feasible method for mass screening of MDR agents from TCMs in vitro.

Computational binding affinity and molecular dynamic characterization of annonaceous acetogenins at nucleotide binding domain (NBD) of multi-drug resistance ATP-binding cassette sub-family B member 1 (ABCB1)

Multi drug resistance (MDR) in tumor might be caused leading to the overexpression of transporters, such as ATP-binding cassette sub-family B member 1 (ABCB1). A combination of non-toxic and potent ABC inhibitors along with conventional anti-cancer drugs is needed to reverse MDR in tumors. A variety of phytochemicals have been previously shown to reverse MDR. Annonaceous acetogenins (AAs) with C₃₅/C₃₇ long-chain fatty acids were reported for their anti-tumor activity, however, their effect on reversing MDR is not yet investigated. We aimed to investigate some selective AAs against the B1 subtype of ABC transporter using computational studies. Various modules of Maestro software were utilized for our in-silico analysis. Few well-characterized AAs were screened for their drug-likeness properties and tested for binding affinity at ATP and drug binding sites of ABCB1 through molecular docking. The stability of the ligand-protein complex (lowest docking score) was then determined by a molecular dynamic (MD) simulation study. Out of 24 AAs, Annonacin A (-8.10 kcal/mol) and Annohexocin (-10.49 kcal/mol) docked with a greater binding affinity at the ATP binding site than the first-generation inhibitor of ABCB1 (Verapamil: -3.86 kcal/mol). MD simulation of Annonacin A: ABCB1 complex for 100 ns also indicated that Annonacin A would stably bind to the ATP binding site. We report that Annonacin A binds at a greater affinity with ABCB1 and might act as a potential drug lead to reverse MDR in tumor cells. Communicated by Ramaswamy H. Sarma.

Adagrasib, a KRAS G12C inhibitor, reverses the multidrug resistance mediated by ABCB1 in vitro and in vivo

Background

Multidrug resistance (MDR) is a complex phenomenon that frequently leads to chemotherapy failure during cancer treatment. The overexpression of ATP-binding cassette (ABC) transporters represents the major mechanism contributing to MDR. To date, no effective MDR modulator has been applied in clinic. Adagrasib (MRTX849), a specific inhibitor targeting KRAS G12C mutant, is currently under investigation in clinical trials for the treatment of non-small cell lung cancer (NSCLC). This study focused on investigating the circumvention of MDR by MRTX849.

Methods

The cytotoxicity and MDR reversal effect of MRTX849 were assessed by MTT assay. Drug accumulation and drug efflux were evaluated by flow cytometry. The MDR reversal by MRTX849 in vivo was investigated in two ABCB1-overexpressing tumor xenograft models in nude mice. The interaction between MRTX849 and ABCB1 substrate binding sites was studied by the [125I]-IAAP-photoaffinity labeling assay. The vanadate-sensitive ATPase assay was performed to identify whether MRTX849 would change ABCB1 ATPase activity. The effect of MRTX849 on expression of ABCB1 and PI3K/AKT signaling molecules was examined by flow cytometry, Western blot and Quantitative Real-time PCR analyses.

Results

MRTX849 was shown to enhance the anticancer efficacy of ABCB1 substrate drugs in the transporter-overexpressing cells both in vitro and in vivo. The MDR reversal effect was specific against ABCB1 because no similar effect was observed in the parental sensitive cells or in ABCG2-mediated MDR cells. Mechanistically, MRTX849 increased the cellular accumulation of ABCB1 substrates including doxorubicin (Dox) and rhodamine 123 (Rho123) in ABCB1-overexpressing MDR cells by suppressing ABCB1 efflux activity. Additionally, MRTX849 stimulated ABCB1 ATPase activity and competed with [125I]-IAAP for photolabeling of ABCB1 in a concentration-dependent manner. However, MRTX849 did not alter ABCB1 expression or phosphorylation of AKT/ERK at the effective MDR reversal drug concentrations.

Conclusions

In summary, MRTX849 was found to overcome ABCB1-mediated MDR both in vitro and in vivo by specifically attenuating ABCB1 efflux activity in drug-resistant cancer cells. Further studies are warranted to translate the combination of MRTX849 and conventional chemotherapy to clinical application for circumvention of MDR.

Discovery of new pyrimidopyrrolizine/indolizine-based derivatives as P-glycoprotein inhibitors: Design, synthesis, cytotoxicity, and MDR reversal activities

Targeting P-glycoprotein (P-gp, ABCB1 transporter), which plays an essential role in multi-drug resistance (MDR) in cancers, with new cytotoxic agents is a promising strategy in cancer chemotherapy. In the current study, we report the synthesis of thirteen novel pyrimidopyrrolizine, pyrimidoindolizine, and diazepinopyrrolizine derivatives. The new compounds exhibited cytotoxic activities against MCF7, A2780 and HT29 cancer cell lines (IC₅₀ = 0.02-19.58 μM) and MRC5 (IC₅₀ = 0.17-20.57 μM). The six most active compounds (23b, 24a,b and, 31c-e) were evaluated for their MDR reversal activities in MCF7/ADR cells. Mechanistic study using real-time PCR revealed the ability of compound 31c to inhibit P-gp. In addition, compound 31c increased the accumulation of Rho123 inside MCF7/ADR cells in a dose-dependent manner compared to verapamil. Compound 31c arrested the cell cycle of MCF7 cells at the G₁ phase. Compound 31c also caused a significant dose-dependent increase of early and late apoptotic events. Molecular docking analysis revealed a high binding affinity for compound 31c toward P-gp. Like zosuquidar, compound 31c displayed one hydrogen bond and several hydrophobic interactions with amino acids in P-gp. These results indicated that compound 31c represents a potential anticancer candidate with MDR reversal activity.

Sterols and triterpenoids from Ganoderma lucidum and their reversal activities of tumor multidrug resistance

Two sterols and seven triterpenoids were isolated and identified from Ganoderma lucidum by silica gel column chromatography, preparative high-performance liquid chromatography and spectra analysis. Then, the multidrug resistance reversal activities of these compounds were assessed using MTT assay. Among these compounds, ganoderol B (3), ganoderone A (4), ganodermanondiol (6) and ganoderiol F (8) were shown to reverse the resistance of human oral epidermoid carcinoma cell line KBv200 to doxorubicin, and the reversal folds were 6.59, 4.70, 4.01 and 7.09, respectively. Ganoderiol F could increase the intracellular accumulation of doxorubicin in KBv200 cells through inhibiting P-glycoprotein transport function. Further mechanistic investigation found that ganoderiol F did not alter P-glycoprotein expression. In conclusion, ganoderiol F has potent effect in reversing P-glycoprotein mediated tumor multidrug resistance. Potential reversal agents against multidrug resistance in tumor may be found in triterpenoids from Ganoderma lucidum.

Assessment of azithromycin as an anticancer agent for treatment of imatinib sensitive and resistant CML cells

INTRODUCTION

Chronic Myeloid Leukemia (CML) is a hematological disease which is characterized by the presence of BCR-ABL fusion protein. Imatinib (IMA), a tyrosine kinase inhibitor of BCR-ABL, is used as a frontline treatment.Although IMA aids in killing a majority of leukemia cells, it may not kill CML stem cells which are the primary roots of disease and therapy resistance. Recently, antimicrobial drugs have been gaining attention because of their selective targeting of cancer cells. Therefore, we now ask if combinational therapy of IMA with a targeted antimicrobial drug Azithromycin (AZT) can enhance the treatment efficiency in IMA resistant CML.

METHODS

K562S (IMA sensitive) and K562R (IMA resistant) cells were treated with increasing concentrations of AZT to determine its effects on cell proliferation and apoptosis. Cell viability, apoptosis, caspase3/7 activity and P-glycoprotein (Pgp) function were investigated with spectrophotometric MTT assay and flow cytometric Annexin V staining, caspase 3/7 activity, and Rhodamine123 staining assays respectively. The expression levels of pro-apoptotic (BAX, BAD and BIM), anti- apoptotic (BCL-XL and BCL-2) and drug transporter (MDR-1 and MRP-1) genes were assessed with qRT-PCR.

RESULTS

AZT treatment alone inhibited cell viability, induced apoptosis and enhanced caspase 3/7 activity in both K562S and high MDR-1 (Pgp) expressing K562R cells. Moreover, combination of AZT/IMA suppressed cell viability, induced apoptosis and caspase3/7 activity more effectively and significantly compared to K562R cells treated with only IMA or AZT. Furthermore, AZT and AZT/IMA combination decreased Pgp function in K562R cells in comparison with their controls. Based on qRT-PCR data, single AZT and combined AZT/IMA treatment also induced BAX/BCL-2 ratio significantly in both K562S and K562R cells.

CONCLUSION

Single AZT and AZT/IMA combinational treatment can be proposed as a promising and effective treatment strategy for CML. One of the mechanisms underlying the potent anticancer effect of combined AZT/IMA could be its ability to inhibit Pgp function and increase intracellular accumulation of IMA which leads to the induction of apoptosis in K562R cells.

Restoring Treatment Response in Colorectal Cancer Cells by Targeting MACC1-Dependent ABCB1 Expression in Combination Therapy

Treatment failure of solid cancers, represented by the development of drug resistance in the primary tumor or later outgrowth of drug resistant metastases, is the major cause of death for cancer patients. It represents an urgent clinical need for predictive biomarkers which indicate the success or failure of standard treatment regimens. Besides treatment prediction, interfering with cellular processes associated with drug resistance might improve treatment response by applying combination therapies. Metastasis-associated in colon cancer (MACC) 1 was identified in our group as a prognostic biomarker in human colorectal cancer, and has been established as key player, prognostic, and predictive biomarker for tumor progression and metastasis in a variety of solid cancers. Besides increased cell proliferation and motility, subsequently contributing to growth and metastatic spread of the primary tumor, MACC1 has also been shown to dysregulate apoptosis and is contributing to treatment resistance. Here we report the MACC1 dependent treatment resistance of colorectal cancer (CRC) cells to standard therapeutics like doxorubicin by upregulating ATP-binding cassette subfamily B member 1 (ABCB1) protein. Overexpression of MACC1 in CRC cells increased both its presence on the ABCB1 promoter and its transcriptional activity, resulting in elevated ABCB1 expression and thus treatment resistance to standard therapeutics. In contrast, depleting MACC1 increased intracellular drug concentrations, leading to better treatment response. We already identified the first MACC1 transcriptional inhibitors, such as lovastatin, by high-throughput screening of clinically approved small molecule drugs. These compounds inhibited cell motility in vitro but also restricted metastasis development in xenograft mouse models by reducing MACC1 expression. Here we report, that treating high MACC1 expressing CRC cells with a combination of statins and standard therapeutics increased the rate of cytotoxicity and resulted in higher treatment response.