PBK/TOPK inhibitor OTS964 resistance is mediated by ABCB1-dependent transport function in cancer: in vitro and in vivo study

Lansoprazole (LPZ) reverses multidrug resistance (MDR) in cancer through impeding ATP-binding cassette (ABC) transporter-mediated chemotherapeutic drug efflux and lysosomal sequestration

AIMS

Lansoprazole is one of the many proton pump inhibitors (PPIs) that acts more strongly with ABCB1 and ABCG2. The present study is to investigate the potential of lansoprazole on reversal of ABCB1/G2-mediated MDR in cancer, in vitro and in vivo.

METHODS

Reversal studies and combination evaluation were conducted to determine the synergistic anti-MDR effects on lansoprazole. Lysosomal staining was used to determination of lansoprazole on ABCB1-mediated lysosomal sequestration. Substrate accumulation and efflux assays, ATPase activity, and molecular docking were conducted to evaluate lansoprazole on ABCB1/G2 functions. Western blot and immunofluorescence were used to detect lansoprazole on ABCB1/G2 expression and subcellular localization. MDR nude mice models were established to evaluate the effects of lansoprazole on MDR in vivo.

RESULTS

Lansoprazole attenuated ABCB1/G2-mediated MDR and exhibited synergistic effects with substrate drugs in MDR cells. In vivo experiments demonstrated that lansoprazole attenuated ABCB1/G2-mediated MDR and exhibited synergistic effects that augmented the sensitivity of substrate anticancer drugs in ABCB1/G2-mediated settings without obvious toxicity. Lansoprazole impeded lysosomal sequestration mediated by ABCB1, leading to a substantial increase in intracellular accumulation of substrate drugs. The effects of lansoprazole were not attributable to downregulation or alterations in subcellular localization of ABCB1/G2. Lansoprazole promoted the ATPase activity of ABCB1/G2 and competitively bound to the substrate-binding region of ABCB1/G2.

CONCLUSIONS

These findings present novel therapeutic avenues whereby the combination of lansoprazole and chemotherapeutic agents mitigates MDR mediated by ABCB1/G2 overexpression.

Andrographolide reverts multidrug resistance in KBChR 8-5 cells through AKT signaling pathway

Multidrug resistance (MDR) is a major obstacle in cancer chemotherapy. P-glycoprotein (P-gp) one of the ATP-binding cassette (ABC) transporters plays an important role in MDR. In this study, we examined the sensitizing property of andrographolide (Andro) to reverse MDR in the drug-resistant KBChR 8-5 cells. Andro exhibited increased cytotoxicity in a concentration-dependent manner in the P-gp overexpressing KBChR 8-5 cells. Furthermore, Andro showed synergistic interactions with PTX and DOX in this drug-resistant cells. Andro co-administration enhanced PTX- and DOX-induced cytotoxicity and reduced cell proliferation in the MDR cancer cells. Moreover, reactive oxygen species (ROS) were elevated with a decrease in the mitochondrial membrane potential (MMP) during Andro and chemotherapeutic drugs combination treatment in the drug-resistant cells. Furthermore, Andro and PTX-induced cell cycle arrest was observed in the drug-resistant cell. We also noticed that the expression of ABCB1 and AKT were downregulated during Andro (4 µM) treatment. Furthermore, Andro treatment enhanced the expression of caspase 3 and caspase 9 in the combinational groups that support the enhanced apoptotic cell death in drug-resistant cancer cells. Therefore, the results reveal that Andro plays a role in the reversal of P-gp-mediated MDR in KBChR 8-5 cells which might be due to regulating ABCB1/AKT signaling pathway.

Pemigatinib, a selective FGFR inhibitor overcomes ABCB1-mediated multidrug resistance in cancer cells

P: -glycoprotein (P-gp/ABCB1) overexpression is one of the primary causes of multidrug resistance (MDR). Therefore, it is crucial to discover effective pharmaceuticals to combat multidrug resistance mediated by ABCB1. Pemigatinib is a selective the fibroblast growth factor receptor (FGFR) inhibitor that is used to treat a variety of solid tumors, Clinical Trials for Urothelial Carcinoma (NCT02872714) completed its research on Pemigatinib. This study aimed to determine whether Pemigatinib can reverse ABCB1-mediated multidrug resistance, as well as its mechanism of action. Pemigatinib substantially reversed ABCB1-mediated multidrug resistance, as determined by a CCK8 assay, and immunofluorescence experiments revealed that Pemigatinib had no effect on the intracellular localization of ABCB1. Pemigatinib was discovered to increase intracellular drug accumulation, thereby reversing multidrug resistance. In addition, Docking analysis revealed that Pemigatinib and ABCB1 have a high affinity for one another. This study concludes that Pemigatinib is capable of reversing the multidrug resistance mediated by ABCB1, offering ideas and references for the clinical application of Pemigatinib.

TOPK promotes the growth of esophageal cancer in vitro and in vivo by enhancing YB1/eEF1A1 signal pathway

T-LAK-originated protein kinase (TOPK), a dual specificity serine/threonine kinase, is up-regulated and related to poor prognosis in many types of cancers. Y-box binding protein 1 (YB1) is a DNA/RNA binding protein and serves important roles in multiple cellular processes. Here, we reported that TOPK and YB1 were both highly expressed in esophageal cancer (EC) and correlated with poor prognosis. TOPK knockout effectively suppressed EC cell proliferation and these effects were reversible by rescuing YB1 expression. Notably, TOPK phosphorylated YB1 at Thr 89 (T89) and Ser 209 (S209) amino acid residues, then the phosphorylated YB1 bound with the promoter of the eukaryotic translation elongation factor 1 alpha 1 (eEF1A1) to activate its transcription. Consequently, the AKT/mTOR signal pathway was activated by up-regulated eEF1A1 protein. Importantly, TOPK inhibitor HI-TOPK-032 suppressed the EC cell proliferation and tumor growth by TOPK/YB1/eEF1A1 signal pathway in vitro and in vivo. Taken together, our study reveals that TOPK and YB1 are essential for the growth of EC, and TOPK inhibitors may be applied to retard cell proliferation in EC. This study highlights the promising therapeutic potential of TOPK as a target for treatment of EC.

Understanding and targeting resistance mechanisms in cancer

Resistance to cancer therapies has been a commonly observed phenomenon in clinical practice, which is one of the major causes of treatment failure and poor patient survival. The reduced responsiveness of cancer cells is a multifaceted phenomenon that can arise from genetic, epigenetic, and microenvironmental factors. Various mechanisms have been discovered and extensively studied, including drug inactivation, reduced intracellular drug accumulation by reduced uptake or increased efflux, drug target alteration, activation of compensatory pathways for cell survival, regulation of DNA repair and cell death, tumor plasticity, and the regulation from tumor microenvironments (TMEs). To overcome cancer resistance, a variety of strategies have been proposed, which are designed to enhance the effectiveness of cancer treatment or reduce drug resistance. These include identifying biomarkers that can predict drug response and resistance, identifying new targets, developing new targeted drugs, combination therapies targeting multiple signaling pathways, and modulating the TME. The present article focuses on the different mechanisms of drug resistance in cancer and the corresponding tackling approaches with recent updates. Perspectives on polytherapy targeting multiple resistance mechanisms, novel nanoparticle delivery systems, and advanced drug design tools for overcoming resistance are also reviewed.

Unlocking phenotypic plasticity provides novel insights for immunity and personalized therapy in lung adenocarcinoma

Background: Unlocking phenotype plasticity (UPP) has been shown to have an essential role in the mechanism of tumor development and therapeutic response. However, the clinical significance of unlocking phenotypic plasticity in patients with lung adenocarcinoma is unclear. This study aimed to explore the roles of unlocking phenotypic plasticity in immune status, prognosis, and treatment in patients with lung adenocarcinoma (LUAD).

Methods: Differentially expressed genes (DEGs) and clinical information of UPP were selected from the cancer genome atlas (TCGA) database, and the GO, KEGG enrichment analyses were performed. The independent prognostic genes were determined by univariate and multivariate Cox regression, and the UPP signature score was constructed. Patients with LUAD were divided into high- and low-risk groups according to the median of score, and the immunocytes and immune function, the gene mutation, and drug sensitivities between the two groups were analyzed. Finally, the results were validated in the GEO database.

Results: Thirty-nine significantly DEGs were determined. Enrichment analysis showed that UPP-related genes were related to protein polysaccharides and drug resistance. The prognostic results showed that the survival of patients in the high-risk group was poorer than that in the low-risk group (p < 0.001). In the high- and low-risk groups, single nucleotide polymorphism (SNP) and C > T are the most common dissent mutations. The contents of immune cells were significantly different between high- and low-risk groups. And the immune functions were also significantly different, indicating that UPP affects the immunity in LUAD. The results from TCGA were validated in the GEO.

Conclusion: Our research has proposed a new and reliable prognosis indicator to predict the overall survival. Evaluation of the UPP could help the clinician to predict therapeutic responses and make individualized treatment plans in patients with LUAD.