Alectinib (CH5424802) antagonizes ABCB1- and ABCG2-mediated multidrug resistance in vitro, in vivo and ex 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.

Foretinib, a c-MET receptor tyrosine kinase inhibitor, tackles multidrug resistance in cancer cells by inhibiting ABCB1 and ABCG2 transporters

BACKGROUND

ABC transporter-mediated multidrug resistance (MDR) remains a major obstacle for cancer pharmacological treatment. Some tyrosine kinase inhibitors (TKIs) have been shown to reverse MDR. The present study was designed to evaluate for the first time whether foretinib, a multitargeted TKI, can circumvent ABCB1 and ABCG2-mediated MDR in treatment-resistant cancer models.

METHODS

Accumulation of fluorescent substrates of ABCB1 and ABCG2 in ABCB1-overexpressing MES-SA/DX5 and ABCG2-overexpressing MCF-7/MX and their parenteral cells was evaluated by flow cytometry. The growth inhibitory activity of single and combination therapy of foretinib and chemotherapeutic drugs on MDR cells was examined by MTT assay. Analysis of combined interaction effects was performed using CalcuSyn software.

RESULTS

It was firstly proved that foretinib increased the intracellular accumulation of rhodamine 123 and mitoxantrone in MES-SA/DX5 and MCF-7/MX cancer cells, with accumulation ratios of 12 and 2.2 at 25 μM concentration, respectively. However, it did not affect the accumulation of fluorescent substrates in the parental cells. Moreover, foretinib synergistically improved the cytotoxic effects of doxorubicin and mitoxantrone. The means of combination index (CI) values at fraction affected (Fa) values of 0.5, 0.75, and 0.9 were 0.64 ± 0.08 and 0.47 ± 0.09, in MES-SA/DX5 and MCF-7/MX cancer cells, respectively. In silico analysis also suggested that the drug-binding domain of ABCB1 and ABCG2 transporters could be considered as potential target for foretinib.

CONCLUSION

Overall, our results suggest that foretinib can target MDR-linked ABCB1 and ABCG2 transporters in clinical cancer therapy.

ATP-Binding Cassette Subfamily G Member 2 in Acute Myeloid Leukemia: A New Molecular Target?

Despite the progress in the knowledge of disease pathogenesis and the identification of many molecular markers as potential targets of new therapies, the cure of acute myeloid leukemia remains challenging. Disease recurrence after an initial response and the development of resistance to old and new therapies account for the poor survival rate and still make allogeneic stem cell transplantation the only curative option. Multidrug resistance (MDR) is a multifactorial phenomenon resulting from host-related characteristics and leukemia factors. Among these, the overexpression of membrane drug transporter proteins belonging to the ABC (ATP-Binding Cassette)-protein superfamily, which diverts drugs from their cellular targets, plays an important role. Moreover, a better understanding of leukemia biology has highlighted that, at least in cancer, ABC protein's role goes beyond simple drug transport and affects many other cell functions. In this paper, we summarized the current knowledge of ABCG2 (formerly Breast Cancer Resistance Protein, BCRP) in acute myeloid leukemia and discuss the potential ways to overcome its efflux function and to revert its ability to confer stemness to leukemia cells, favoring the persistence of leukemia progenitors in the bone marrow niche and justifying relapse also after therapy intensification with allogeneic stem cell transplantation.

Perspectives on drug repurposing to overcome cancer multidrug resistance mediated by ABCB1 and ABCG2

The overexpression of the human ATP-binding cassette (ABC) transporters in cancer cells is a common mechanism involved in developing multidrug resistance (MDR). Unfortunately, there are currently no approved drugs specifically designed to treat multidrug-resistant cancers, making MDR a significant obstacle to successful chemotherapy. Despite over two decades of research, developing transporter-specific inhibitors for clinical use has proven to be a challenging endeavor. As an alternative approach, drug repurposing has gained traction as a more practical method to discover clinically effective modulators of drug transporters. This involves exploring new indications for already-approved drugs, bypassing the lengthy process of developing novel synthetic inhibitors. In this context, we will discuss the mechanisms of ABC drug transporters ABCB1 and ABCG2, their roles in cancer MDR, and the inhibitors that have been evaluated for their potential to reverse MDR mediated by these drug transporters. Our focus will be on providing an up-to-date report on approved drugs tested for their inhibitory activities against these drug efflux pumps. Lastly, we will explore the challenges and prospects of repurposing already approved medications for clinical use to overcome chemoresistance in patients with high tumor expression of ABCB1 and/or ABCG2.

An update on Alectinib: a first line treatment for ALK-positive advanced lung cancer

INTRODUCTION

Alectinib is a second-generation, anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitor (TKI) for the treatment of ALK+ non-small cell lung cancer (NSCLC) and is able to induce significant and durable CNS responses. However, long-term use of alectinib has been clinically reported to cause some serious and even life-threatening adverse events. There are currently no effective interventions for its adverse events, and this undoubtedly leads to delays in patient treatment and limits its long-term clinical use.

AREAS COVERED

Based on the clinical trials conducted so far, we summarize the efficacy and adverse events that occurred, especially those related to cardiovascular disorders, gastrointestinal disorders, hepatobiliary disorders, musculoskeletal and connective tissue disorders, skin and subcutaneous tissue disorders, and respiratory disorders. The factors that may influence alectinib selection are also described. Findings are based on a PubMed literature search of clinical and basic science research papers spanning 1998-2023.

EXPERT OPINION

The significant prolongation of patient survival compared with first-generation ALK inhibitor suggests its potential as a first-line treatment for the NSCLC, but the severe adverse events of alectinib limit its long-term clinical use. Future research should focus on the exact mechanisms of these toxicities, how to alleviate the adverse events caused by alectinib clinically, and the development of next-generation drugs with reduced toxicities.

Lactate drives cellular DNA repair capacity: Role of lactate and related short-chain fatty acids in cervical cancer chemoresistance and viral infection

The characteristic feature of a cancer microenvironment is the presence of a highly elevated concentration of L-lactate in the tumor niche. The lactate-rich environment is also maintained by commensal mucosal microbiota, which has immense potential for affecting cancer cells through its receptoric and epigenetic modes of action. Some of these lactate activities might be associated with the failure of anticancer therapy as a consequence of the drug resistance acquired by cancer cells. Upregulation of cellular DNA repair capacity and enhanced drug efflux are the most important cellular mechanisms that account for ineffective radiotherapy and drug-based therapies. Here, we present the recent scientific knowledge on the role of the HCA1 receptor for lactate and lactate intrinsic activity as an HDAC inhibitor in the development of an anticancer therapy-resistant tumor phenotype, with special focus on cervical cancer cells. In addition, a recent study highlighted the viable role of interactions between mammalian cells and microorganisms in the female reproductive tract and demonstrated an interesting mechanism regulating the efficacy of retroviral transduction through lactate-driven modulation of DNA-PKcs cellular localization. To date, very few studies have focused on the mechanisms of lactate-driven enhancement of DNA repair and upregulation of particular multidrug-resistance proteins in cancer cells with respect to their intracellular regulatory mechanisms triggered by lactate. This review presents the main achievements in the field of lactate impact on cell biology that may promote undesirable alterations in cancer physiology and mitigate retroviral infections.

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.

Lazertinib improves the efficacy of chemotherapeutic drugs in ABCB1 or ABCG2 overexpression cancer cells in vitro, in vivo, and ex vivo

Multidrug resistance (MDR) is the major cause of chemotherapy failure, which is usually caused by the overexpression of ATP-binding cassette (ABC) transporters such as ABCB1 and ABCG2. To date, no MDR modulator has been clinically approved. Here, we found that lazertinib (YH25448; a novel third-generation tyrosine kinase inhibitor [TKI]) could enhance the anticancer efficacy of MDR transporter substrate anticancer drugs in vitro，in vivo, and ex vivo. Mechanistically, lazertinib was shown to inhibit the drug efflux activities of ABCB1 and ABCG2 and thus increase the intracellular accumulation of the transporter substrate anticancer drug. Moreover, lazertinib was found to stimulate the ATPase activity of ABCB1/ABCG2 and inhibit the photolabeling of the transporters by ¹²⁵I-iodoarylazidoprazosin (IAAP). However, lazertinib neither changed the expression or locolization of ABCB1 and ABCG2 nor blocked the signal pathway of Akt or Erk1/2 at a drug concentration effective for MDR reversal. Overall, our results demonstrate that lazertinib effectively reverses ABCB1- or ABCG2-mediated MDR by competitively binding to the ATP-binding site and inhibiting drug efflux function. This is the first report demonstrating the novel combined use of lazertinib and conventional chemotherapeutical drugs to overcome MDR in ABCB1/ABCG2-overexpressing cancer cells.

Mechanistic basis of breast cancer resistance protein inhibition by new indeno[1,2-b]indoles

The ATP-binding cassette transporter ABCG2 mediates the efflux of several chemotherapeutic drugs, contributing to the development of multidrug resistance (MDR) in many cancers. The most promising strategy to overcome ABCG2-mediated MDR is the use of specific inhibitors. Despite many efforts, the identification of new potent and specific ABCG2 inhibitors remains urgent. In this study, a structural optimization of indeno[1,2-b]indole was performed and a new generation of 18 compounds was synthesized and tested as ABCG2 inhibitors. Most compounds showed ABCG2 inhibition with IC₅₀ values below 0.5 µM. The ratio between cytotoxicity (IG₅₀) and ABCG2 inhibition potency (IC₅₀) was used to identify the best inhibitors. In addition, it was observed that some indeno[1,2-b]indole derivatives produced complete inhibition, while others only partially inhibited the transport function of ABCG2. All indeno[1,2-b]indole derivatives are not transported by ABCG2, and even the partial inhibitors are able to fully chemosensitize cancer cells overexpressing ABCG2. The high affinity of these indeno[1,2-b]indole derivatives was confirmed by the strong stimulatory effect on ABCG2 ATPase activity. These compounds did not affect the binding of conformation-sensitive antibody 5D3 binding, but stabilized the protein structure, as revealed by the thermostabilization assay. Finally, a docking study showed the indeno[1,2-b]indole derivatives share the same binding site as the substrate estrone-3-sulfate.

Poziotinib Inhibits the Efflux Activity of the ABCB1 and ABCG2 Transporters and the Expression of the ABCG2 Transporter Protein in Multidrug Resistant Colon Cancer Cells

Simple Summary

Globally, colorectal cancer (CRC) is a leading cause of cancer deaths and chemotherapy, in combination with radiotherapy when appropriate, is used to treat the majority of CRC patients. However, the acquisition or development of drug resistance can decrease, or even abolish, the efficacy of chemotherapy. ATP-binding cassette (ABC) transporters, particularly, the ABCB1 and ABCG2 transporter, are mediators of multidrug resistance (MDR) in certain types of cancer cells. The aim of our in vitro study was to determine if poziotinib can overcome MDR to certain chemotherapeutic drugs in colon cancer cells. Our results indicated that in MDR CRC cell lines, poziotinib inhibits the transport function of the ABCB1 and ABCG2 transporters, increasing the intracellular accumulation of certain anticancer drugs, and thus, their efficacy. Furthermore, poziotinib decreased the expression of the ABCG2 protein. Therefore, if our results can be translated to humans, they suggest that using poziotinib in combination with certain anticancer drugs may be of therapeutic benefit in colorectal cancer patients.

Abstract

Colorectal cancer (CRC) is a leading cause of cancer deaths in the United States. Currently, chemotherapy is a first-line treatment for CRC. However, one major drawback of chemotherapy is the emergence of multidrug resistance (MDR). It has been well-established that the overexpression of the ABCB1 and/or ABCG2 transporters can produce MDR in cancer cells. In this study, we report that in vitro, poziotinib can antagonize both ABCB1- and ABCG2-mediated MDR at 0.1–0.6 μM in the human colon cancer cell lines, SW620/Ad300 and S1-M1-80. Mechanistic studies indicated that poziotinib increases the intracellular accumulation of the ABCB1 transporter substrates, paclitaxel and doxorubicin, and the ABCG2 transporter substrates, mitoxantrone and SN-38, by inhibiting their substrate efflux function. Accumulation assay results suggested that poziotinib binds reversibly to the ABCG2 and ABCB1 transporter. Furthermore, western blot experiments indicated that poziotinib, at 0.6 μM, significantly downregulates the expression of the ABCG2 but not the ABCB1 transporter protein, suggesting that the ABCG2 reversal effect produced by poziotinib is due to transporter downregulation and inhibition of substrate efflux. Poziotinib concentration-dependently stimulated the ATPase activity of both ABCB1 and ABCG2, with EC₅₀ values of 0.02 μM and 0.21 μM, respectively, suggesting that it interacts with the drug-substrate binding site. Molecular docking analysis indicated that poziotinib binds to the ABCB1 (−6.6 kcal/mol) and ABCG2 (−10.1 kcal/mol) drug-substrate binding site. In summary, our novel results show that poziotinib interacts with the ABCB1 and ABCG2 transporter, suggesting that poziotinib may increase the efficacy of certain chemotherapeutic drugs used in treating MDR CRC.

Superior Pyrimidine Derivatives as Selective ABCG2 Inhibitors and Broad-Spectrum ABCB1, ABCC1, and ABCG2 Antagonists

In the search for highly effective modulators addressing ABCG2-mediated MDR, 23 pyrimidines were synthesized and biologically assessed. Seven derivatives with (a) nitrogen- and/or halogen-containing residue(s) had extraordinary potencies against ABCG2 (IC₅₀ < 150 nM). The compounds competitively inhibited ABCG2-mediated Hoechst 33342 transport but were not substrates of ABCG2. The most potent MDR reverser, compound 19, concentration-dependently increased SN-38-mediated cancer cell death at 11 nM (EC₅₀), time-dependently doubled SN-38 toxicity in a period of 7 days at 10 nM, and half-maximally accelerated cell death combined with SN-38 at 17 nM. No induction of ABCG2 was observed. Furthermore, 11 pyrimidines were revealed as triple ABCB1/ABCC1/ABCG2 inhibitors. Five possessed IC₅₀ values below 10 μM against each transporter, classifying them as some of the 50 most potent multitarget ABC transporter inhibitors. The most promising representative, compound 37, reversed ABCB1-, ABCC1-, and ABCG2-mediated MDR, making it one of the three most potent ABC transporter inhibitors and reversers of ABC transporters-mediated MDR.

Sitravatinib, a Tyrosine Kinase Inhibitor, Inhibits the Transport Function of ABCG2 and Restores Sensitivity to Chemotherapy-Resistant Cancer Cells in vitro

Sitravatinib, also called MGCD516 or MG-516, is a broad-spectrum tyrosine kinase inhibitor (TKI) under phase III clinical evaluation. Herein, we explored the activity of sitravatinib toward multidrug resistance (MDR) by emphasizing its inhibitory effect on ATP-binding cassette super-family G member 2 (ABCG2). ABCG2 is a member of ATP-binding cassette (ABC) transporter family and plays a critical role in mediating MDR. Sitravatinb received an outstanding docking score for binding to the human ABCG2 model (PDB code: 6ETI) among thirty screened TKIs. Also, an MTT assay indicated that sitravatinib at 3 μM had the ability to restore the antineoplastic effect of various ABCG2 substrates in both drug-selected and gene-transfected ABCG2-overexpressing cell lines. In further tritium-labeled mitoxantrone transportation study, sitravatinib at 3 μM blocked the efflux function mediated by ABCG2 and as a result, increased the intracellular concentration of anticancer drugs. Interestingly, sitravatinib at 3 μM altered neither protein expression nor subcellular localization of ABCG2. An ATPase assay demonstrated that ATPase activity of ABCG2 was inhibited in a concentration-dependent manner with sitravatinib; thus, the energy source to pump out compounds was interfered. Collectively, the results of this study open new avenues for sitravatinib working as an ABCG2 inhibitor which restores the antineoplastic activity of anticancer drugs known to be ABCG2 substrates.

Rociletinib (CO-1686) enhanced the efficacy of chemotherapeutic agents in ABCG2-overexpressing cancer cells in vitro and in vivo

Overexpression of adenosine triphosphate (ATP)-binding cassette subfamily G member 2 (ABCG2) in cancer cells is known to cause multidrug resistance (MDR), which severely limits the clinical efficacy of chemotherapy. Currently, there is no FDA-approved MDR modulator for clinical use. In this study, rociletinib (CO-1686), a mutant-selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), was found to significantly improve the efficacy of ABCG2 substrate chemotherapeutic agents in the transporter-overexpressing cancer cells in vitro and in MDR tumor xenografts in nude mice, without incurring additional toxicity. Mechanistic studies revealed that in ABCG2-overexpressing cancer cells, rociletinib inhibited ABCG2-mediated drug efflux and increased intracellular accumulation of ABCG2 probe substrates. Moreover, rociletinib, inhibited the ATPase activity, and competed with [¹²⁵I] iodoarylazidoprazosin (IAAP) photolabeling of ABCG2. However, ABCG2 expression at mRNA and protein levels was not altered in the ABCG2-overexpressing cells after treatment with rociletinib. In addition, rociletinib did not inhibit EGFR downstream signaling and phosphorylation of protein kinase B (AKT) and extracellular signal-regulated kinase (ERK). Our results collectively showed that rociletinib reversed ABCG2-mediated MDR by inhibiting ABCG2 efflux function, thus increasing the cellular accumulation of the transporter substrate anticancer drugs. The findings advocated the combination use of rociletinib and other chemotherapeutic drugs in cancer patients with ABCG2-overexpressing MDR tumors.

Pharmacokinetic-Based Drug-Drug Interactions with Anaplastic Lymphoma Kinase Inhibitors: A Review

Anaplastic lymphoma kinase (ALK) inhibitors are important treatment options for non-small-cell lung cancer (NSCLC), associated with ALK gene rearrangement. Patients with ALK gene rearrangement show sensitivity to and benefit clinically from treatment with ALK tyrosine kinase inhibitors (ALK-TKIs). To date, crizotinib, ceritinib, alectinib, brigatinib, lorlatinib, and entrectinib have received approval from the US Food and Drug Administration and/or the European Medicines Agency for use during the treatment of ALK-gene-rearrangement forms of NSCLC. Although the oral route of administration is convenient and results in good compliance among patients, oral administration can be affected by many factors, such as food, intragastric pH, cytochrome P450 enzymes, transporters, and p-glycoprotein. These factors can result in increased risks for serious adverse events or can lead to reduced therapeutic effects of ALK-TKIs. This review characterizes and summarizes the pharmacokinetic parameters and drug–-drug interactions associated with ALK-TKIs to provide specific recommendations for oncologists and clinical pharmacists when prescribing ALK-TKIs.

Repurposing Tyrosine Kinase Inhibitors to Overcome Multidrug Resistance in Cancer: A Focus on Transporters and Lysosomal Sequestration

Tyrosine kinase inhibitors (TKIs) are being increasingly used to treat various malignancies. Although they were designed to target aberrant tyrosine kinases, they are also intimately linked with the mechanisms of multidrug resistance (MDR) in cancer cells. MDR-related solute carrier (SLC) and ATB-binding cassette (ABC) transporters are responsible for TKI uptake and efflux, respectively. However, the role of TKIs appears to be dual because they can act as substrates and/or inhibitors of these transporters. In addition, several TKIs have been identified to be sequestered into lysosomes either due to their physiochemical properties or via ABC transporters expressed on the lysosomal membrane. Since the development of MDR represents a great concern in anticancer treatment, it is important to elucidate the interactions of TKIs with MDR-related transporters as well as to improve the properties that would prevent TKIs from diffusing into lysosomes. These findings not only help to avoid MDR, but also help to define the possible impact of combining TKIs with other anticancer drugs, leading to more efficient therapy and fewer adverse effects in patients.

Ensartinib (X-396) Effectively Modulates Pharmacokinetic Resistance Mediated by ABCB1 and ABCG2 Drug Efflux Transporters and CYP3A4 Biotransformation Enzyme

Ensartinib (X-396) is a promising tyrosine kinase inhibitor currently undergoing advanced clinical evaluation for the treatment of non-small cell lung cancer. In this work, we investigate possible interactions of this promising drug candidate with ATP-binding cassette (ABC) drug efflux transporters and cytochrome P450 biotransformation enzymes (CYPs), which play major roles in multidrug resistance (MDR) and pharmacokinetic drug-drug interactions (DDIs). Accumulation studies showed that ensartinib is a potent inhibitor of ABCB1 and ABCG2 transporters. Additionally, incubation experiments with recombinant CYPs showed that ensartinib significantly inhibits CYP3A4 and CYP2C9. Subsequent molecular docking studies confirmed these findings. Drug combination experiments demonstrated that ensartinib synergistically potentiates the antiproliferative effects of daunorubicin, mitoxantrone, and docetaxel in ABCB1, ABCG2, and CYP3A4-overexpressing cellular models, respectively. Advantageously, ensartinib’s antitumor efficiency was not compromised by the presence of MDR-associated ABC transporters, although it acted as a substrate of ABCB1 in Madin-Darby Canine Kidney II (MDCKII) monolayer transport assays. Finally, we demonstrated that ensartinib had no significant effect on the mRNA-level expression of examined transporters and enzymes in physiological and lung tumor cellular models. In conclusion, ensartinib may perpetrate clinically relevant pharmacokinetic DDIs and modulate ABCB1-, ABCG2-, and CYP3A4-mediated MDR. The in vitro findings presented here will provide a valuable foundation for future in vivo investigations.

Acquired Resistance to Alectinib in ALK-Rearranged Lung Cancer due to ABCC11/MRP8 Overexpression in a Clinically Paired Resistance Model

Alectinib is used as a first-line treatment for anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancer (NSCLC). Whereas other ALK inhibitors have been reported to be involved in resistance to ATP-binding cassette (ABC) transporters, no data are available regarding the association between resistance to alectinib and ABC-transporters. To investigate whether ABC-transporters contribute to alectinib resistance, ABC-transporter expression in alectinib-resistant cell lines derived from a patient with ALK-rearranged NSCLC and from H2228 lung cancer cells was evaluated and compared with that in each parent cell type. ATP-binding cassette subfamily C member 11 (ABCC11) expression was significantly increased in alectinib-resistant cell lines compared with that in alectinib-sensitive lines. ABCC11 inhibition increased sensitivity to alectinib in vitro ABCC11-overexpressing cells were established by transfection of an ABCC11 expression vector into H2228 cells, while control cells were established by transfecting H2228 cells with an empty vector. ABCC11-overexpressing cells exhibited decreased sensitivity to alectinib compared with that of control cells in vitro Moreover, the tumor growth rate following alectinib treatment was higher in ABCC11-overexpressing cells than that in control cells in vivo In addition, the intracellular alectinib concentration following exposure to 100 nmol/L alectinib was significantly lower in the ABCC11-overexpressing cell line compared with that in control cells. This is the first preclinical evidence showing that ABCC11 expression may be involved in acquired resistance to alectinib.

Reversal Effect of ALK Inhibitor NVP-TAE684 on ABCG2-Overexpressing Cancer Cells

Failure of cancer chemotherapy is mostly due to multidrug resistance (MDR). Overcoming MDR mediated by overexpression of ATP binding cassette (ABC) transporters in cancer cells remains a big challenge. In this study, we explore whether NVP-TAE684, a novel ALK inhibitor which has the potential to inhibit the function of ABC transport, could reverse ABC transporter-mediated MDR. MTT assay was carried out to determine cell viability and reversal effect of NVP-TAE684 in parental and drug resistant cells. Drug accumulation and efflux assay was performed to examine the effect of NVP-TAE684 on the cellular accumulation and efflux of chemotherapeutic drugs. The ATPase activity of ABCG2 transporter in the presence or absence of NVP-TAE684 was conducted to determine the impact of NVP-TAE684 on ATP hydrolysis. Western blot analysis and immunofluorescence assay were used to investigate protein molecules related to MDR. In addition, the interaction between NVP-TAE684 and ABCG2 transporter was investigated via in silico analysis. MTT assay showed that NVP-TAE684 significantly decreased MDR caused byABCG2-, but not ABCC1-transporter. Drug accumulation and efflux tests indicated that the effect of NVP-TAE684 in decreasing MDR was due to the inhibition of efflux function of ABCG2 transporter. However, NVP-TAE684 did not alter the expression or change the subcellular localization of ABCG2 protein. Furthermore, ATPase activity analysis indicated that NVP-TAE684 could stimulate ABCG2 ATPase activity. Molecular in silico analysis showed that NVP-TAE684 interacts with the substrate binding sites of the ABCG2 transporter. Taken together, our study indicates that NVP-TAE684 could reduce the resistance of MDR cells to chemotherapeutic agents, which provides a promising strategy to overcome MDR.

Dual Inhibitors as a New Challenge for Cancer Multidrug Resistance Treatment

BACKGROUND

Dual-targeting in cancer treatment by a single drug is an unconventional approach in relation to drug combinations. The rationale for the development of dualtargeting agents is to overcome incomplete efficacy and drug resistance frequently present when applying individual targeting agents. Consequently, -a more favorable outcome of cancer treatment is expected with dual-targeting strategies.

METHODS

We reviewed the literature, concentrating on the association between clinically relevant and/or novel dual inhibitors with the potential to modulate multidrug resistant phenotype of cancer cells, particularly the activity of P-glycoprotein. A balanced analysis of content was performed to emphasize the most important findings and optimize the structure of this review.

RESULTS

Two-hundred and forty-five papers were included in the review. The introductory part was interpreted by 9 papers. Tyrosine kinase inhibitors' role in the inhibition of Pglycoprotein and chemosensitization was illustrated by 87 papers. The contribution of naturalbased compounds in overcoming multidrug resistance was reviewed using 92 papers, while specific dual inhibitors acting against microtubule assembling and/or topoisomerases were described with 55 papers. Eleven papers gave an insight into a novel and less explored approach with hybrid drugs. Their influence on P-glycoprotein and multidrug resistance was also evaluated.

CONCLUSION

These findings bring into focus rational anticancer strategies with dual-targeting agents. Most evaluated synthetic and natural drugs showed a great potential in chemosensitization. Further steps in this direction are needed for the optimization of anticancer treatment.

Apatinib Mesylate in the treatment of advanced progressed lung adenocarcinoma patients with EGFR-TKI resistance -A Multicenter Randomized Trial

Few pieces of evidence have been published on the use of Apatinib Mesylate (AM) against EGFR-TKI resistance in lung adenocarcinoma (LA) patients. Here, we investigate the clinical efficacy and safety of AM in the treatment of advanced progressed epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI) resistant LA patients. We conducted a double-blind, randomized controlled trial in 68 patients admitted to 18 hospitals of Anhui province in China. The efficacy and safety of AM treatment were evaluated in terms of progression-free survival (PFS), objective response rate (ORR), and disease control rate (DCR), as well as related adverse events (AE). A literature knowledge database analysis and a pathway model reconstruction were performed to decipher the relevant mechanism may be involved. Our results showed that, compared to the control group, AM presented improved efficacy in PFS (P = 0.033), ORR (P < 0.001), and DCR (P < 0.001). No significant difference was observed between case and control group in terms of AE, and no drug-related death occurred. Pathway analysis supports that Apatinib can be repurposed for the treatment of LA. Our results suggested that AM could be a potential option for advanced progressed LA patients to combat EGFR-TKI resistance.

[Peripheral blood exosomes from patients with multiple myeloma mediate bortezomib resistance in cultured multiple myeloma cells]

OBJECTIVE

To investigate the role of exosome in mediating bortezomib (Btz) resistance in multiple myeloma cells in vitro and explore the underlying mechanisms.

METHODS

Peripheral blood samples were collected from 15 patients with multiple myeloma with Btz tolerance, and serum exosomes were isolated by ultracentrifugation and identified with electron microscopy, NTA and Western blotting. In vitro cultured multiple myeloma cells were treated with gradient concentrations of Btz to determine the optimal drug concentration for subsequent experiment. The cells were pretreated with different concentrations of exosomes, and their sensitivity to BTZ was assessed using MTS assay. We searched the exosome database Exocarta and used STRING to generate the network map and the protein interaction graph.

RESULTS

The diameters of the vesicles isolated from the peripheral blood of the patients were mostly below 200 nm with a mean particle size of 153 nm and a mode of 140.1 nm. The results of Western blotting showed that the isolated exosomes expressed the marker proteins CD63, Tsg101 and Alix. In cultured multiple myeloma cells, pretreatment with exosomes resulted in a decreased sensitivity of the cells to bortezomib, and longer treatment durations and higher exosome concentrations consistently enhanced the resistance of the cells to the same Btz concentration. Analysis of the Exocarta database identified human serum exosomal proteins ABCB1, ABCB4, PDCD6IP, and EGFR, among which EGFR served as a network node.

CONCLUSIONS

Exosome within a specific concentration range may serve as a signal carrier to mediate the resistance of multiple myeloma cells to Btz. EGFR likely plays a key role to promote exosome-mediated Btz resistance in myeloma cells.

Interactions of Alectinib with Human ATP-Binding Cassette Drug Efflux Transporters and Cytochrome P450 Biotransformation Enzymes: Effect on Pharmacokinetic Multidrug Resistance

Alectinib is a tyrosine kinase inhibitor currently used as a first-line treatment of anaplastic lymphoma kinase-positive metastatic nonsmall cell lung cancer (NSCLC). In the present work, we investigated possible interactions of this novel drug with ATP-binding cassette (ABC) drug efflux transporters and cytochrome P450 (P450) biotransformation enzymes that play significant roles in the phenomenon of multidrug resistance (MDR) of cancer cells as well as in pharmacokinetic drug-drug interactions. Using accumulation studies in Madin-Darby canine kidney subtype 2 (MDCKII) cells alectinib was identified as an inhibitor of ABCB1 and ABCG2 but not of ABCC1. In subsequent drug combination studies, we demonstrated the ability for alectinib to effectively overcome MDR in ABCB1- and ABCG2-overexpressing MDCKII and A431 cells. To describe the pharmacokinetic interaction profile of alectinib in a complete fashion, its possible inhibitory properties toward clinically relevant P450 enzymes (i.e., CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4, or CYP3A5) were evaluated using human P450-expressing insect microsomes, revealing alectinib as a poor interactor. Advantageously for its use in pharmacotherapy, alectinib further exhibited negligible potential to cause any changes in expression of ABCB1, ABCG2, ABCC1, CYP1A2, CYP3A4, and CYP2B6 in intestine, liver, and NSCLC models. Our in vitro observations might serve as a valuable foundation for future in vivo studies that could support the rationale for our conclusions and possibly enable providing more efficient and safer therapy to many oncological patients.

WYE-354 restores Adriamycin sensitivity in multidrug-resistant acute myeloid leukemia cell lines

Multidrug resistance (MDR) is a major reason for the failure of acute myeloid leukemia (AML) therapy. Agents that reverse MDR and sensitize AML cells to chemotherapy are of great clinical significance. The present study developed Adriamycin (Adr)-resistant cell lines, namely K562/Adr200 and K562/Adr500, which exhibited MDR. The upregulation of ATP-binding cassette subfamily B member 1 (ABCB1) was confirmed as the mechanism of resistance by reverse transcription-quantitative polymerase chain reaction and western blot analyses. Subsequently, the role of the mammalian target of rapamycin (mTOR) kinase inhibitor, WYE-354, in sensitizing the K562/Adr200 and K562/Adr500 cell lines to Adr was evaluated. At sub-cytotoxic concentrations, WYE-354 increased Adr cytotoxicity in the K562/Adr200 and K562/Adr500 cells. WYE-354 restored Adr sensitivity in the resistant cells by inhibiting ABCB1-mediated substrate efflux, thereby leading to an accumulation of Adr, an increase in Adr-mediated G2/M cell cycle arrest and the induction of apoptosis. Furthermore, WYE-354 stimulated the ATPase activity of ABCB1, which was consistent with in silico predictions using a human ABCB1 mouse homology model, indicating that WYE-354 is a potent substrate of ABCB1. WYE-354 did not regulate the expression of ABCB1 at the concentrations used in the present study. These findings indicate that WYE-354 may be a competitive inhibitor of ABCB1-mediated efflux and a potential candidate in combination with standard chemotherapy for overcoming MDR. Further clinical investigations are warranted to validate this combination in vivo.

LS. Diverse Targeted Approaches to Battle Multidrug Resistance in Cancer

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The efficacy of successful cancer therapies is frequently hindered by the development of drug resistance in the tumor. The term ‘drug resistance’ is used to illustrate the decreased effectiveness of a drug in curing a disease or alleviating the symptoms of the patient. This phenomenon helps tumors to survive the damage caused by a specific drug or group of drugs. In this context, studying the mechanisms of drug resistance and applying this information to design customized treatment regimens can improve therapeutic efficacy as well as the curative outcome. Over the years, numerous Multidrug Resistance (MDR) mechanisms have been recognized and tremendous effort has been put into developing agents to address them. The integration of data emerging from the elucidation of molecular and biochemical pathways and specific tumor-associated factors has shown tremendous promise within the oncology community for improving patient outcomes. In this review, we provide an overview of the utility of these molecular and biochemical signaling processes as well as tumor-associated factors associated with MDR, for the rational selection of cancer treatment strategies.

A Novel Synthetic Dihydroindeno[1,2-b] Indole Derivative (LS-2-3j) Reverses ABCB1- and ABCG2-Mediated Multidrug Resistance in Cancer Cells

10-oxo-5-(3-(pyrrolidin-1-yl) propyl)-5,10-dihydroindeno [1,2-b] indol-9-yl propionate (LS-2-3j) is a new chemically synthesized indole compound and some related analogues are known to be inhibitors (such as alectinib and Ko143) of ATP-binding cassette (ABC) transporters, especially the ABC transporter subfamily B member 1 (ABCB1) and the ABC transporter subfamily G member 2 (ABCG2). This study aimed to evaluate the multidrug resistance (MDR) reversal effects and associated mechanisms of LS-2-3j in drug-resistant cancer cells. The inhibition of cell proliferation in tested agents was evaluated by the 3-(4,5-dimethylthiazol)-2,5-diphenyltetrazolium bromide (MTT) assay. Accumulation or efflux of chemotherapy drugs was analyzed by flow cytometry. The ATPase activity was measured using an ATPase activity assay kit. The mRNA transcripts and protein expression levels were detected by real-time PCR and Western blot, respectively. In this connection, LS-2-3j significantly enhanced the activity of chemotherapeutic drugs in MDR cells and could significantly increase the intracellular accumulation of doxorubicin (DOX) and mitoxantrone (MITX) by inhibiting the function of the efflux pumps in ABCB1- or ABCG2-overexpressing cells. Furthermore, reduced ATPase activity, mRNA transcription, and protein expression levels of ABCB1 and ABCG2 were observed in a concentration dependent manner in MDR cancer cells.

Olmutinib (HM61713) reversed multidrug resistance by inhibiting the activity of ATP-binding cassette subfamily G member 2 in vitro and in vivo

Overexpressing of ATP-binding cassette (ABC) transporters is the essential cause of multidrug resistance (MDR), which is a significant hurdle to the success of chemotherapy in many cancers. Therefore, inhibiting the activity of ABC transporters may be a logical approach to circumvent MDR. Olmutinib is an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), which has been approved in South Korea for advanced EGFR T790M-positive non-small cell lung cancer (NSCLC). Here, we found that olmutinib significantly increased the sensitivity of chemotherapy drug in ABCG2-overexpressing cells. Furthermore, olmutinib could also increase the retention of doxorubicin (DOX) and rhodamine 123 (Rho 123) in ABC transporter subfamily G member 2 (ABCG2)-overexpressing cells. In addition, olmutinib was found to stimulate ATPase activity and inhibit photolabeling of ABCG2 with [¹²⁵I]-iodoarylazidoprazosin (IAAP). However, olmutinib neither altered ABCG2 expression at protein and mRNA levels nor blocked EGFR, Her-2 downstream signaling of AKT and ERK. Importantly, olmutinib enhanced the efficacy of topotecan on the inhibition of S1-MI-80 cell xenograft growth. All the results suggest that olmutinib reverses ABCG2-mediated MDR by binding to ATP bind site of ABCG2 and increasing intracellular chemotherapeutic drug accumulation. Our findings encouraged to further clinical investigation on combination therapy of olmutinib with conventional chemotherapeutic drugs in ABCG2-overexpressing cancer patients.

Dacomitinib potentiates the efficacy of conventional chemotherapeutic agents via inhibiting the drug efflux function of ABCG2 in vitro and in vivo

BACKGROUND

ATP-binding cassette subfamily G member 2 (ABCG2), a member of the ABC transporter superfamily proteins, mediates multidrug resistance (MDR) by transporting substrate anticancer drugs out of cancer cells and decreasing their intracellular accumulation. MDR is a major hurdle to successful chemotherapy. A logical approach to overcome MDR is to inhibit the transporter. However, no safe and effective MDR inhibitor has been approved in the clinic.

METHODS

The MTT assay was used to evaluate cell cytotoxicity and MDR reversal effect. Drug efflux and intracellular drug accumulation were measured by flow cytometry. The H460/MX20 cell xenograft model was established to evaluate the enhancement of anticancer efficacy of topotecan by dacomitinib in vivo. To ascertain the interaction of dacomitinib with the substrate binding sites of ABCG2, the competition of dacomitinib for photolabeling of ABCG2 with [¹²⁵I]- iodoarylazidoprazosin (IAAP) was performed. Vanadate-sensitive ATPase activity of ABCG2 was measured in the presence of a range of different concentrations of dacomitinib to evaluate the effect of dacomitinib on ATP hydrolysis as the energy source of the transporter. A flow cytometry-based assay and western blotting were employed to study whether dacomitininb could inhibit the expression level of ABCG2. The mRNA expression levels of ABCG2 were analyzed by real-time quantitative RT-PCR. The protein expression level of AKT, ERK and their phosphorylations were detected by Western blotting.

RESULTS

Here, we found that dacomitinib, an irreversible pan-ErbB tyrosine kinase inhibitor (TKI) in phase III clinical trial, could enhance the efficacy of conventional chemotherapeutic agents specifically in ABCG2-overexpressing MDR cancer cells but not in the parental sensitive cells. Dacomitinib was found to significantly increase the accumulation of ABCG2 probe substrates [doxorubicin (DOX),Rhodamine 123 (Rho 123) and Hoechst 33342] by inhibiting the transporter efflux function. Moreover, dacomitinib stimulated ABCG2 ATPase activity and competed with [¹²⁵I]-IAAP photolabeling of ABCG2 in a concentration-dependent manner. However, dacomitinib did not alter ABCG2 expression at protein and mRNA levels or inhibit ErbB downstream signaling of AKT and ERK. Importantly, dacomitinib significantly enhanced the efficacy of topotecan in ABCG2-overexpressing H460/MX20 cell xenografts in nude mice without incurring additional toxicity.

CONCLUSIONS

These results suggest that dacomitinib reverses ABCG2-mediated MDR by inhibiting ABCG2 efflux function and increasing intracellular accumulation of anticancer agents. Our findings advocate further clinical investigation of combinations of dacomitinib and conventional chemotherapy in cancer patients with ABCG2-overexpressing MDR tumors.

Tyrosine kinase inhibitors enhanced the efficacy of conventional chemotherapeutic agent in multidrug resistant cancer cells

Multidrug resistance (MDR) triggered by ATP binding cassette (ABC) transporter such as ABCB1, ABCC1, ABCG2 limited successful cancer chemotherapy. Unfortunately, no commercial available MDR modulator approved by FDA was used in clinic. Tyrosine kinase inhibitors (TKIs) have been administrated to fight against cancer for decades. Almost TKI was used alone in clinic. However, drug combinations acting synergistically to kill cancer cells have become increasingly important in cancer chemotherapy as an approach for the recurrent resistant disease. Here, we summarize the effect of TKIs on enhancing the efficacy of conventional chemotherapeutic drug in ABC transporter-mediated MDR cancer cells, which encourage to further discuss and study in clinic.

Alectinib

Alectinib is an ATP-competitive small molecule and a second-generation inhibitor of ALK. EML4-ALK rearrangement is found in 3-5% of patients with NSCLC. The first-generation inhibitor crizotinib has changed the treatment dramatically, though most of the patients show disease progression within one year. Extra-thoracic progress, i.e., CNS metastases is common. The second-generation inhibitor alectinib has shown significant improvement in PFS and a remarkable prolongation of time to CNS progression. Alectinib has received approval as first-line therapy as well as second-line therapy after crizotinib failure. The toxicity profile is favorable compared to crizotinib and chemotherapy.