Multidrug-resistant Cells Research Articles

Endogenous Magnetic Lipid Droplet-Mediated Cascade-Targeted Sonodynamic Therapy as an Approach to Reversing Breast Cancer Multidrug Resistance.

Multidrug resistance (MDR) has emerged as a major barrier to effective breast cancer treatment, contributing to high rates of chemotherapy failure and disease recurrence. There is thus a pressing need to overcome MDR and to facilitate the efficient and precise treatment of breast cancer in a targeted manner. In this study, endogenous functional lipid droplets (IR780@LDs-Fe3O4/OA) were developed and used to effectively overcome the limited diffusion distance of reactive oxygen species owing to their amenability to cascade-targeted delivery, thereby facilitating precise and effective sonodynamic therapy (SDT) for MDR breast cancer. Initially, IR780@LDs-Fe3O4/OA was efficiently enriched within tumor sites in a static magnetic field, achieving the visualization of tumor treatment. Subsequently, the cascade-targeted SDT combined with the Fenton effect induced lysosome membrane permeabilization and relieved lysosomal sequestration, thus elevating drug concentration at the target site. This treatment approach also suppressed ATP production, thereby inhibiting P-glycoprotein-mediated chemotherapeutic drug efflux. This cascade-targeted SDT strategy significantly increased the sensitivity of MDR cells to doxorubicin, increasing the IC50 value of doxorubicin by approximately 10-fold. Moreover, the cascade-targeted SDT also altered the gene expression profiles of MDR cells and suppressed the expression of MDR-related genes. In light of these promising results, the combination of cascade-targeted SDT and conventional chemotherapy holds great clinical promise as an effective treatment modality with excellent biocompatibility that can improve MDR breast cancer patient outcomes.

BETULINIC ACID ACTS IN SYNERGISM WITH IMATINIB MESYLATE TRIGGERING APOPTOSIS IN MDR LEUKEMIA CELLS.

Chronic myeloid leukemia (CML) is a myeloproliferative disease, characterized by the presence of the oncogene BCR-ABL. Imatinib mesylate (IMA) is the first line treatment for CML, and some treatment resistance has been reported. Natural products are rich sources of bioactive compounds with biological effects, opening a possibility to alter cell susceptibility to drugs such as imatinib. Herein, we evaluated the interference of betulinic acid and ursolic acid in glycoprotein P (P-gp) activity and the possible synergistic effect when associated with IMA by the Chou-Talalay method. Ursolic acid presented an IC50 of 14,0µM and 19,6 µM for K562 and Lucena 1, respectively, whilst betulinic acid presented an IC50 of 8.6 μM and 12.5μM, for these cell lines. Evaluation of the combination of terpenoids and imatinib mesylate revealed that ursolic acid or betulinic acid acts in synergism with IMA, as indicated by the combination indexes (CI<1). Analysis of annexin V labelling demonstrated that combination of IMA with betulinic acid enhances the inhibition on cell proliferation via apoptosis pathway, with caspases 3/7 activation after 24 hours of treatment, and inhibition of the STAT5/Survivin pathway, decreasing cell viability. The combination of natural products and IMA on a multidrug-resistant leukemia cell line is a promising strategy for CML treatment.

Vesicle-Transported Multidrug Resistance as a Possible Therapeutic Target of Natural Compounds.

A key role of extracellular vesicles (EVs) is mediating both cell-cell and cell-stroma communication in pathological/physiological conditions. EVs from resistant tumor cells can transport different molecules like P-glycoprotein (P-gp), acting as a shuttle between donor and recipient cells, resulting in a phenotypic change. The aim of our work was to isolate, characterize, and inhibit the release of EVs in two multidrug resistance (MDR) cancer models: MCF-7R (breast cancer cell line) and HL-60R (acute myeloid leukemia cell line). The existence of P-gp in EVs from MDR cells was confirmed by Western blotting assays. The characterization of EVs was carried out by evaluating the size using NTA and the presence of specific markers such as CD63, Hsp70 and Syntenin. The ability of HL-60R and MCF-7R to perform horizontal transfer of P-gp via EVs to sensitive cells was assessed using three different methods. The acquisition of resistance and its inhibition in recipient cells was confirmed by MTS 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay. Our data showed that cell lines (MDR) release P-gp-loaded EVs, unlike sensitive cells. The acquisition of resistance determined by the incorporation of P-gp into the membrane of sensitive cells was confirmed by the reduced cytotoxic activity of doxorubicin. Natural compounds such as curcumin, lupeol, and heptacosane can block vesicular transfer and restore the sensitivity of HL-60 and MCF-7 cells. Our study demonstrates that natural inhibitors able to reverse this mechanism may represent a new therapeutic strategy to limit the propagation of the resistant phenotype.

Epertinib counteracts multidrug resistance in cancer cells by antagonizing the drug efflux function of ABCB1 and ABCG2

A significant hurdle in cancer treatment arises from multidrug resistance (MDR), often due to overexpression of ATP-binding cassette (ABC) transporters like ABCB1 and/or ABCG2 in cancer cells. These transporters actively diminish the efficacy of cytotoxic drugs by facilitating ATP hydrolysis-dependent drug efflux and reducing intracellular drug accumulation in cancer cells. Addressing multidrug-resistant cancers poses a significant challenge due to the lack of approved treatments, prompting the exploration of alternative avenues like drug repurposing (also referred to as drug repositioning) of molecularly targeted agents to reverse MDR-mediated by ABCB1 and/or ABCG2 in multidrug-resistant cancer cells. Epertinib, a potent inhibitor of EGFR and HER2 currently in clinical trials for solid tumors, was investigated for its potential to resensitize ABCB1- and ABCG2-overexpressing multidrug-resistant cancer cells to chemotherapeutic agents. Our findings reveal that at sub-toxic, submicromolar concentrations, epertinib restores the sensitivity of multidrug-resistant cancer cells to cytotoxic drugs in a concentration-dependent manner. The results demonstrate that epertinib enhances drug-induced apoptosis in these cancer cells by impeding the drug-efflux function of ABCB1 and ABCG2 without altering their expression. ATPase activity and molecular docking were employed to reveal potential interaction sites between epertinib and the drug-binding pockets of ABCB1 and ABCG2. In summary, our study demonstrates an additional pharmacological capability of epertinib against the activity of ABCB1 and ABCG2. These findings suggest that incorporating epertinib into combination therapy could be advantageous for a specific patient subset with tumors exhibiting high levels of ABCB1 or ABCG2, warranting further exploration.

Sensitization of Multidrug Resistant Cancer Cells to Doxorubicin Using Ebselen by Disturbing Cellular Redox Status.

Multidrug resistance (MDR) poses a significant problem in cancer treatment, often causing adverse effects during chemotherapy. Ebselen (Ebs), a synthetic organoselenium compound, affects cellular redox status in cancer cells. In the study, we observed that Ebs disrupted cellular redox balance and sensitized drug-resistant cells to doxorubicin (DOX) treatment. The combination of Ebs and DOX led to increased intracellular reactive oxygen species (ROS) levels and lipid peroxidation while decreasing the activity of thioredoxin reductase (TrxR) and cellular antioxidants in drug-resistant cells. Furthermore, this combination treatment demonstrated notable chemosensitizing effects by reducing cell viability and proliferation in MDR cells compared to DOX treatment alone. Additionally, the combination of Ebs and DOX induced DNA fragmentation and exhibited G2/M phase cell cycle arrest. Immunofluorescent analysis revealed that the Ebs and DOX combination upregulated the expression of p53 and p21, which activated the mitochondrial-dependent apoptotic pathway. The combination treatment also enhanced the upregulation of proapoptotic markers such as Bax, Caspase-3, -9, and cytochrome C, while downregulating the expression of the antiapoptotic marker Bcl-2. Therefore, the current discoveries suggest that Ebs could be employed as a drug candidate for reversing MDR in cancer cells by regulating cellular redox homeostasis.

Highly Cytotoxic Cryptophycin Derivatives with Modification in Unit D for Conjugation.

Cytotoxic payloads for drug conjugates suitable for directed tumor therapy need to be highly potent and require a functional group for conjugation with the homing device (antibody, peptide, or small molecule). Cryptophycins are cyclodepsipeptides that stand out from the realm of natural products due to their extraordinarily high cytotoxicity. However, the installation of a suitable conjugation handle without compromising the toxicity is highly challenging. The unit D, natively 2-hydroxyisocaproic acid (leucic acid), was envisaged as a promising attachment site based on structural information from X-ray analysis. A versatile, scalable and efficient synthetic route towards conjugable cryptophycins with modification in unit D was developed and an array of new cryptophycin analogues was synthesized. Several derivatives, especially those containing lipophilic groups with low steric demand such as alkylated amino groups, exhibit low picomolar cytotoxicity often combined with efficacy against multidrug-resistant tumor cells. The newly established cryptophycin analogues comprise a broad range of relevant functional groups used as conjugation handles, among them amino, hydroxy, carboxy, as well as sulfur-containing derivatives. X-ray crystallographic analysis of a tubulin-bound cryptophycin together with quantitative structure activity relationship manifested rationales for the synthesis of most potent cryptophycin derivatives and further confirmed the suitability of modifications in unit D.

Developing a Rhodium(III) Complex to Reprogram the Tumor Immune and Metabolic Microenvironments: Overcoming Multidrug Resistance and Metastasis in Non-Small Cell Lung Cancer.

To effectively inhibit the growth and metastasis of non-small cell lung cancer (NSCLC) and overcome its multidrug resistance (MDR), we designed and synthesized a series of rhodium (Rh, III) 2-benzoylpyridine thiosemicarbazone complexes. Through studying their structure-activity relationships, we identified the Rh(III) complex (Rh4) with excellent cytotoxicity against multidrug-resistant lung cancer cells (A549/ADR cells). Additionally, we successfully constructed an apoferritin (AFt) nanoparticle (NP) delivery system (AFt-Rh4 NPs). Importantly, AFt-Rh4 NPs not only exhibited excellent antitumor and antimetastatic capabilities against multidrug-resistant NSCLC in vivo but also demonstrated enhanced targeting ability and reduced systemic toxicity and adverse effects. Furthermore, we confirmed and elucidated the mechanisms by which Rh4/AFt-Rh4 NPs inhibit tumor metastasis and reverse MDR in NSCLC. This was achieved by reprogramming the immune and metabolic tumor microenvironments through induction of immunogenic cell death and inhibition of dual-energy metabolism.

MiR-133 promotes the multidrug resistance of acute myeloid leukemia cells (HL-60/ADR) to daunorubicin.

This study aimed to explore the role and molecular mechanism of miR-133 in multidrug resistance in acute myeloid leukemia (AML) and provide a new theoretical basis for the treatment and prognosis of AML patients. We performed experiments at the cellular level. RT‒qPCR and Western blotting were used to detect gene and protein expression; cell viability was measured with CCK-8 assays; apoptosis was detected via flow cytometry; and a dual-luciferase reporter gene assay was used to verify the binding between miR-133 and CXCL12. In this study, we found that miR-133 was upregulated in HL-60/ADR multidrug-resistant cells. Functionally, the inhibition of miR-133 alleviated the resistance of HL-60/ADR cells to daunorubicin (DNR). After inhibiting miR-133 in HL-60/ADR cells treated with DNR, the expression of the intracellular drug resistance-related proteins MRP562 and P-gp was inhibited, cell proliferation decreased, and apoptosis increased. Mechanistically, the NF-κB signaling pathway regulates the expression of miR-133 in HL-60/ADR cells, and the targeting of CXCL12 by miR-133 enhances the resistance of HL-60/ADR cells to DNR. In conclusion, the NF-κB signaling pathway regulates the expression of miR-133, and inhibiting miR-133 expression can target CXCL12 to increase the sensitivity of HL-60/ADR cells to DNR.

A New Class of Gold(I) NHC Complexes with Proapoptotic and Resensitizing Properties towards Multidrug Resistant Leukemia Cells Overexpressing BCL-2.

From previous studies, it is evident that metal-organic gold(I) complexes have antiproliferative activities. The aim of this study is not only to find new anticancer agents but also to overcome existing cytostatic resistance in cancer cells. The synthesis and medicinal evaluation of two cationic 1,3-disubstituted gold(I) bis-tetrazolylidene complexes 1 and 2 are reported. To determine apoptosis-inducing properties of the complexes, DNA fragmentation was measured using propidium iodide staining followed by flow cytometry. Gold(I) complex 1 targets explicitly malignant cells, effectively inhibiting their growth and selectively inducing apoptosis without signs of necrosis. Even in cells resistant to common treatments such as doxorubicin, it overcomes multidrug resistance and sensitizes existing drug-resistant cells to common cytostatic drugs. It is assumed that gold(I) complex 1 involves the mitochondrial pathway in apoptosis and targets members of the BCL-2 family, enhancing its potential as a therapeutic agent in cancer treatment.

Curcumin-Dichloroacetate Hybrid Molecule as an Antitumor Oral Drug against Multidrug-Resistant Advanced Bladder Cancers.

Tumor cells produce excessive reactive oxygen species (ROS) but cannot detoxify ROS if they are due to an external agent. An agent that produces toxic levels of ROS, specifically in tumor cells, could be an effective anticancer drug. CMC-2 is a molecular hybrid of the bioactive polyphenol curcumin conjugated to dichloroacetate (DCA) via a glycine bridge. The CMC-2 was tested for its cytotoxic antitumor activities and killed both naïve and multidrug-resistant (MDR) bladder cancer (BCa) cells with equal potency (<1.0 µM); CMC-2 was about 10-15 folds more potent than curcumin or DCA. Growth of human BCa xenograft in mice was reduced by >50% by oral gavage of 50 mg/kg of CMC-2 without recognizable systemic toxicity. Doses that used curcumin or DCA showed minimum antitumor effects. In vitro, the toxicity of CMC-2 in both naïve and MDR cells depended on increased intracellular ROS in tumor cells but not in normal cells at comparable doses. Increased ROS caused the permeabilization of mitochondria and induced apoptosis. Further, adding N-Acetyl cysteine (NAC), a hydroxyl radical scavenger, abolished excessive ROS production and CMC-2's cytotoxicity. The lack of systemic toxicity, equal potency against chemotherapy -naïve and resistant tumors, and oral bioavailability establish the potential of CMC-2 as a potent drug against bladder cancers.

Genetically engineered CD276-anchoring biomimetic nanovesicles target senescent escaped tumor cells to overcome chemoresistant and immunosuppressive breast cancer

Chemotherapy-induced cellular senescence leads to an increased proportion of cancer stem cells (CSCs) in breast cancer (BC), contributing to recurrence and metastasis, while effective means to clear them are currently lacking. Herein, we aim to develop new approaches for selectively killing senescent-escape CSCs. High CD276 (95.60%) expression in multidrug-resistant BC cells, facilitates immune evasion by low-immunogenic senescent escape CSCs. CALD1, upregulated in ADR-resistant BC, promoting senescent-escape of CSCs with an anti-apoptosis state and upregulating CD276, PD-L1 to promote chemoresistance and immune escape. We have developed a controlled-released thermosensitive hydrogel containing pH- responsive anti-CD276 scFV engineered biomimetic nanovesicles to overcome BC in primary, recurrent, metastatic and abscopal humanized mice models. Nanovesicles coated anti-CD276 scFV selectively fuses with cell membrane of senescent-escape CSCs, then sequentially delivers siCALD1 and ADR due to pH-responsive MnP shell. siCALD1 together with ADR effectively induce apoptosis of CSCs, decrease expression of CD276 and PD-L1, and upregulate MHC I combined with Mn2+ to overcome chemoresistance and promote CD8+T cells infiltration. This combined therapeutic approach reveals insights into immune surveillance evasion by senescent-escape CSCs, offering a promising strategy to immunotherapy effectiveness in cancer therapy.

A Review of the Efficacy of Nanomaterial-Based Natural Photosensitizers to Overcome Multidrug Resistance in Cancer.

Natural photosensitizers (PS) are compounds derived from nature, with photodynamic properties. Natural PSs have a similar action to that of commercial PSs, where cancer cell death occurs by necrosis, apoptosis, and autophagy through ROS generation. Natural PSs have garnered great interest over the last few decades because of their high biocompatibility and good photoactivity. Specific wavelengths could cause phytochemicals to produce harmful ROS for photodynamic therapy (PDT). However, natural PSs have some shortcomings, such as reduced solubility and lower uptake, making them less appropriate for PDT. Nanotechnology offers an opportunity to develop suitable carriers for various natural PSs for PDT applications. Various nanoparticles have been developed to improve the outcome with enhanced solubility, optical adsorption, and tumor targeting. Multidrug resistance (MDR) is a phenomenon in which tumor cells develop resistance to a wide range of structurally and functionally unrelated drugs. Over the last decade, several researchers have extensively studied the effect of natural PS-based photodynamic treatment (PDT) on MDR cells. Though the outcomes of clinical trials for natural PSs were inconclusive, significant advancement is still required before PSs can be used as a PDT agent for treating MDR tumors. This review addresses the increasing literature on MDR tumor progression and the efficacy of PDT, emphasizing the importance of developing new nano-based natural PSs in the fight against MDR that have the required features for an MDR tumor photosensitizing regimen.

Safe, simple and multifunctional hydroxyapatite nanoparticles for efficient overcoming of tumor multidrug resistance

Multidrug resistance (MDR) of cancer is the most common obstacle to chemotherapy. Many complex multifunctional nanoparticles have been developed for combination of two or more therapeutics to overcome MDR. Unlike these sophisticated nanoparticles, hydroxyapatite nanoparticles (HAPNs) were found to be able to inhibit cell proliferation of various human cancer cells. Herein, with different MDR cells and chemotherapeutic drugs, we tested whether HAPNs can be widely applied in fighting cancer drug resistance. Rod-shaped HAPNs were synthesized by the aqueous precipitation and then successfully loaded with paclitaxel (PTX) and doxorubicin (DOX) by physical adsorption to obtain pH-responsive drug-loaded nanoparticles, PHAPNs and DHAPNs, respectively. Plain HAPNs exhibited selective cytotoxicity to drug-resistant breast cancer cells MCF-7/ADR, lung cancer cells H69AR and A549/PTX, while spared normal human liver cells L-02. HAPN treatment led to an increase in the apoptosis ratio, a decrease in cell viability and a sustained increase in intracellular calcium ion level in MDR cells. Furthermore, HAPNs facilitated the delivery and accumulation of both drugs, thereby improving the DOX-induced DNA damage in H69AR cells, as well as the acetylation of α-tubulin and cell cycle arrest led by PTX in MCF-7/ADR and A549/PTX cells. Drug-loaded HAPNs greatly enhanced mitochondrial damage, inhibited ATP synthesis and efflux pump activity, and triggered both the intrinsic and extrinsic apoptosis induced by HAPNs or drugs alone. HAPNs acted synergistically with DOX and PTX, resulting in a >6-fold reduction in the IC50 compared with free drugs for these MDR cells. Notably, PHAPNs successfully suppressed the tumor growth in A549/PTX xenograft mice and exhibited excellent biocompatibility in vivo. These findings demonstrated that HAPNs may be widely utilized to reverse the resistance of various drug-resistant cells, providing a simple but practical approach to overcome MDR of cancer.

Discovery of Potent Isoquinolinequinone N-Oxides to Overcome Cancer Multidrug Resistance.

Multidrug resistance (MDR) of human tumors has resulted in an immediate need to develop appropriate new drugs. This work outlines the development of 20 potent IQQ N-oxide derivatives in two isomeric families, both exhibiting nanomolar GI50 against human tumor cell lines. Preliminary NCI-60 tumor screening sees the C(6) isomers achieve a mean GI50 > 2 times lower than the corresponding C(7) isomers. MDR evaluation of nine selected compounds reveals that each presents lower GI50 concentrations in two MDR tumor cell lines. Four of the series display nanomolar GI50 values against MDR cells, having selectivity ratios up to 2.7 versus the sensitive (parental) cells. The most potent compound 25 inhibits the activity of drug efflux pumps in MDR cells, causes significant ROS accumulation, and potently inhibits cell proliferation, causing alterations in the cell cycle profile. Our findings are confirmed by 3D spheroid models, providing new candidates for studies against MDR cancers.

Sorcin in Cancer Development and Chemotherapeutic Drug Resistance.

SOluble Resistance-related Calcium-binding proteIN (sorcin) earned its name due to its co-amplification with ABCB1 in multidrug-resistant cells. Initially thought to be an accidental consequence of this co-amplification, recent research indicates that sorcin plays a more active role as an oncoprotein, significantly impacting multidrug resistance (MDR). Sorcin is a highly expressed calcium-binding protein, often overproduced in human tumors and multidrug-resistant cancers, and is a promising novel MDR marker. In tumors, sorcin levels inversely correlate with both patient response to chemotherapy and overall prognosis. Multidrug-resistant cell lines consistently exhibit higher sorcin expression compared to their parental counterparts. Furthermore, sorcin overexpression via gene transfection enhances drug resistance to various chemotherapeutic drugs across numerous cancer lines. Conversely, silencing sorcin expression reverses drug resistance in many cell lines. Sorcin participates in several mechanisms of MDR, including drug efflux, drug sequestering, cell death inhibition, gene amplification, epithelial-to-mesenchymal transition, angiogenesis, and metastasis. The present review focuses on the structure and function of sorcin, on sorcin's role in cancer and drug resistance, and on the approaches aimed at targeting sorcin.

Solanine Inhibits Proliferation and Angiogenesis and Induces Apoptosis through Modulation of EGFR Signaling in KB-ChR-8-5 Multidrug-Resistant Oral Cancer Cells.

Background: The most important factors contributing to multi-drug resistance in oral cancer include overexpression of the EGFR protein and the downstream malignancy regulators that are associated with it. This study investigates the impact of solanine on inflammation, proliferation, and angiogenesis inhibition in multidrug-resistant oral cancer KB-Chr-8-5 cells through inhibition of the EGFR/PI3K/Akt/NF-κB signaling pathway. Methods: Cell viability was assessed using an MTT assay to evaluate cytotoxic effects. Production of reactive oxygen species (ROS), mitochondrial membrane potential (ΔΨM), and AO/EtBr staining were analyzed to assess apoptosis and mitochondrial dysfunction. Western blotting was employed to examine protein expression related to angiogenesis, apoptosis, and signaling pathways. Experiments were conducted in triplicate. Results: Solanine treatment at concentrations of 10, 20, and 30 μM significantly increased ROS production, which is indicative of its antioxidant properties. This increase was associated with decreased mitochondrial membrane potential (ΔΨM) with p < 0.05, suggesting mitochondrial dysfunction. Inhibition of EGFR led to reduced activity of PI3K, Akt, and NF-κB, resulting in decreased expression of iNOS, IL-6, Cyclin D1, PCNA, VEGF, Mcl-1, and HIF-1α and increased levels of the apoptotic proteins Bax, caspase-9, and caspase-3. These changes collectively inhibited the growth of multidrug-resistant (MDR) cancer cells. Conclusions: Solanine acts as a potent disruptor of cellular processes by inhibiting the EGFR-mediated PI3K/Akt/NF-κB signaling pathway. These results suggest that solanine holds promise as a potential preventive or therapeutic agent against multidrug-resistant cancers.

Synthesis and Systematic Investigation of Lepidiline A and Its Gold(I), Silver(I), and Copper(I) Complexes Using In Vitro Cancer Models and Multipotent Stem Cells.

The imidazole alkaloid lepidiline A from the root of Lepidium meyenii has a moderate to low in vitro anticancer effect. Our aim was to extend cytotoxicity investigations against a panel of cancer cells, including multidrug-resistant cancer cells, and multipotent stem cells. Lepidiline A is a N-heterocyclic carbene precursor, therefore a suitable ligand source for metal complexes. Thus, we synthesized lepidiline A and its copper(I), gold(I), and silver(I) complexes and tested them against ovarian, gastrointestinal, breast, and uterine cancer cells and bone marrow-derived and adipose-derived mesenchymal stem cells. Lepidiline A and its copper complex demonstrated moderate cytotoxicity, while silver and gold complexes exhibited significantly enhanced and consistent cytotoxicity against both cancer and stem cell lines. ABCB1 in the multidrug-resistant uterine sarcoma line conferred significant resistance against lepidiline A and the copper-lepidiline A complex, but not against the silver and gold complexes. Our results indicate that only the copper complex induced a significant and universal increase in the production of reactive oxygen species within cells. In summary, binding of metal ions to lepidiline A results in enhanced cytotoxicity with the nature of the metal ion playing a critical role in determining its properties.

Dual Inhibitors of P-gp and Carbonic Anhydrase XII (hCA XII) against Tumor Multidrug Resistance with Piperazine Scaffold.

A new series of piperazine derivatives were synthesized and studied with the aim of obtaining dual inhibitors of P-glycoprotein (P-gp) and carbonic anhydrase XII (hCA XII) to synergistically overcome the P-gp-mediated multidrug resistance (MDR) in cancer cells expressing the two proteins, P-gp and hCA XII. Indeed, these hybrid compounds contain both P-gp and hCA XII binding groups on the two nitrogen atoms of the heterocyclic ring. All compounds showed good inhibitory activity on each protein (P-gp and hCA XII) studied individually, and many of them showed a synergistic effect in the resistant HT29/DOX and A549/DOX cell lines which overexpress both the target proteins. In particular, compound 33 displayed the best activity by enhancing the cytotoxicity and intracellular accumulation of doxorubicin in HT29/DOX and A549/DOX cells, thus resulting as promising P-gp-mediated MDR reverser with a synergistic mechanism. Furthermore, compounds 13, 27 and 32 induced collateral sensitivity (CS) in MDR cells, as they were more cytotoxic in resistant cells than in the sensitive ones; their CS mechanisms were extensively investigated.

Sponge-derived alkaloid AP-7 as a sensitizer to cisplatin in the treatment of multidrug-resistant NSCLC via Chk1-dependent mechanisms.

Multidrug resistance is a substantial obstacle in treating non-small cell lung cancer (NSCLC) with therapies like cisplatin (DDP)-based adjuvant chemotherapy and EGFR-tyrosine kinase inhibitors (TKIs). Aaptamine-7 (AP-7), a benzonaphthyridine alkaloid extracted from Aaptos aaptos sponge, has been shown to exhibit a broad spectrum of anti-tumor activity. However, the anti-cancer activity of AP-7 in combination with DDP and its molecular mechanisms in multidrug-resistant NSCLC are not yet clear. Our research indicates that AP-7 bolsters the growth inhibition activity of DDP on multidrug-resistant NSCLC cells. AP-7 notably disrupts DDP-induced cell cycle arrest and amplifies DDP-induced DNA damage effects in these cells. Furthermore, the combination of AP-7 and DDP downregulates Chk1 activation, interrupts the DNA damage repair-dependent Chk1/CDK1 pathway, and helps to overcome drug resistance and boost apoptosis in multidrug-resistant NSCLC cells and a gefitinib-resistant xenograft mice model. In summary, AP-7 appears to enhance DDP-induced DNA damage by impeding the Chk1 signaling pathway in multidrug-resistant NSCLC, thereby augmenting growth inhibition, both in vitro and in vivo. These results indicate the potential use of AP-7 as a DDP sensitizer in the treatment of multidrug-resistant NSCLC.

Establishment and characterization of a novel multidrug-resistant pancreatic ductal adenocarcinoma cell line, PDAC-X1

Drug resistance remains a significant challenge in the treatment of pancreatic cancer. The development of drug-resistant cell lines is crucial to understanding the underlying mechanisms of resistance and developing novel drugs to improve clinical outcomes. Here, a novel pancreatic cancer cell line, PDAC-X1, derived from Chinese patients has been established. PDAC-X1 was characterized by the immune phenotype, biology, genetics, molecular characteristics, and tumorigenicity. In vitro analysis revealed that PDAC-X1 cells exhibited epithelial morphology and cell markers (CK7 and CK19), expressed cancer-associated markers (E-cadherin, Vimentin, Ki-67, CEA, CA19-9), and produced pancreatic cancer-like organs in suspension culture. In vivo analysis showed that PDAC-X1 cells maintained tumorigenicity with a 100% tumor formation rate. This cell line exhibited a complex karyotype, dominated by subtriploid karyotypes. In addition, PDAC-X1 cells exhibited intrinsic multidrug resistance to multiple drugs, including gemcitabine, paclitaxel, 5-fluorouracil, and oxaliplatin. In conclusion, the PDAC-X1 cell line has been established and characterized, representing a useful and valuable preclinical model to study the underlying mechanisms of drug resistance and develop novel drug therapeutics to improve patient outcomes.