Expression Of Multidrug Resistance Gene Research Articles

Abstract 4557: Overexpressed CPAP promotes cancer stemness and enhances chemo-resistance in HCC

Abstract Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and is highly resistant to chemotherapy and targeted therapy. It was reported that HCC cancer stem cells (CSCs) are involved in chemo-drug resistance by regulating multidrug resistance (MDR) gene expression, such as ABC transporters. Our previous reports indicated that CPAP, a centrosomal protein, can promote HCC progression by up-regulating NF-κB and STAT3 transcriptional activities. Here, we demonstrated that overexpressed CPAP can increase cancer stemness features and CSCs-derived sorafenib resistance in HCC by up-regulating the transcriptional activities of NF-κB and β-catenin. Importantly, CPAP stably expressed HCC spheroids are significantly resistance to sorafenib in vitro and in vivo. Our results suggested that CD24 and ABCG2 are two potential downstream effectors in CPAP overexpressed HCC. CPAP can transcriptionally up-regulate CD24 and ABCG2 expression via Wnt/β-catenin and NF-κB signaling pathways, respectively; high CPAP/ABCG2/CD24 expression levels are negatively correlated with disease-specific survival rates in HCC patients. Combined treatment with sorafenib and Wnt/β-catenin pathway inhibitor PRI-724 significantly inhibited CPAP-overexpressing Hep3B spheroids-derived tumor growth in a xenograft mouse model. Our study highlights the oncogenic role of CPAP in promoting CSCs-induced sorafenib resistance in HCC and provides insights into potential therapeutic strategies. Citation Format: Liang-Yi Hung. Overexpressed CPAP promotes cancer stemness and enhances chemo-resistance in HCC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4557.

MYB alternative promoter activity is increased in adenoid cystic carcinoma metastases and is associated with a specific gene expression signature

ObjectiveAdenoid cystic carcinoma (ACC) is a head and neck cancer with a poor long-term prognosis that shows frequent local recurrences and distant metastases. The tumors are characterized by MYB oncogene activation and are notoriously unresponsive to systemic therapies. The biological underpinnings behind therapy resistance of disseminated ACC are largely unknown. Here, we have studied the molecular and clinical significance of MYB alternative promoter (TSS2) usage in ACC metastases. Materials and methodsMYB TSS2 activity was investigated in primary tumors and metastases from 26 ACC patients using RNA-sequencing and quantitative real-time PCR analysis. Differences in global gene expression between MYB TSS2 high and low cases were studied, and pathway analyses were performed. ResultsMYB TSS2 activity was significantly higher in ACC metastases than in primary tumors (median activity 15.1 vs 3.0, P = 0.0003). MYB TSS2 high ACC metastases showed a specific gene expression signature, including increased expression of multi-drug resistance genes and canonical MYB target genes, and suppression of the p53 and NOTCH pathways. ConclusionsCollectively, our findings indicate that elevated MYB TSS2 activity is associated with metastases, potential drug resistance, and augmented MYB-driven gene expression in ACC. Our study advocates the need for new therapies that specifically target MYB and drug resistance mechanisms in disseminated ACC.

Brain-Decellularized ECM-Based 3D Myeloid Sarcoma Platform: Mimicking Adaptive Phenotypic Alterations in the Brain.

Leukemia circulates in the bloodstream and induces various symptoms and complications. Occasionally, these cells accumulate in non-marrow tissues, forming a tumor-like myeloid sarcoma (MS). When the blast-stage leukemia cells invade the brain parenchyma, intracranial MS occurs, leading to a challenging prognosis owing to the limited penetration of cytostatic drugs into the brain and the development of drug resistance. The scarcity of tissue samples from MS makes understanding the phenotypic changes occurring in leukemia cells within the brain environment challenging, thereby hindering development of effective treatment strategies for intracranial MS. This study presents a novel 3D in vitro model mimicking intracranial MS, employing a hydrogel scaffold derived from the brain-decellularized extracellular matrix in which suspended leukemia cells are embedded, simulating the formation of tumor masses in the brain parenchyma. This model reveals marked phenotypic changes in leukemia cells, including altered survival, proliferation, differentiation, and cell cycle regulation. Notably, proportion of dormant leukemia stem cells increases and expression of multidrug resistance genes is upregulated, leading to imatinib resistance, mirroring the pathological features of in vivo MS tissue. Furthermore, suppression of ferroptosis is identified as an important characteristic of intracranial MS, providing valuable insights for the development of targeted therapeutic strategies.

SEW2871 reduces seizures via the sphingosine 1-phosphate receptor-1 pathway in the pentylenetetrazol and phenobarbitone kindling model of drug-refractory epilepsy.

Epilepsy is a prevalent neurological disorder characterized by neuronal hypersynchronous discharge in the brain, leading to central nervous system (CNS) dysfunction. Despite the availability of anti-epileptic drugs (AEDs), resistance to AEDs is the greatest challenge in treating epilepsy. The role of sphingosine-1-phosphate-receptor 1 (S1PR1) in drug-resistant epilepsy is unexplored. This study investigated the effects of SEW2871, a potent S1PR1 agonist, on a phenobarbitone (PHB)-resistant pentylenetetrazol (PTZ)-kindled Wistar rat model. We measured the messenger ribonucleic acid (mRNA) expression of multi-drug resistance 1 (MDR1) and multi-drug resistance protein 5 (MRP5) as indicators for drug resistance. Rats received PHB + PTZ for 62 days to develop a drug-resistant epilepsy model. From day 48, SEW2871 (0.25, 0.5, 0.75 mg/kg, intraperitoneally [i.p.]) was administered for 14 days. Seizure scoring, behaviour, oxidative markers like reduced glutathione, catalase, superoxide dismutase, inflammatory markers like interleukin 1 beta tumour necrosis factor alpha, interferon gamma and mRNA expression (MDR1 and MRP5) were assessed, and histopathological assessments were conducted. SEW2871 demonstrated dose-dependent improvements in seizure scoring and neurobehavioral parameters with a reduction in oxidative and inflammation-induced neuronal damage. The S1PR1 agonist also downregulated MDR1 and MRP5 gene expression and significantly decreased the number of dark-stained pyknotic nuclei and increased cell density with neuronal rearrangement in the rat brain hippocampus. These findings suggest that SEW2871 might ameliorate epileptic symptoms by modulating drug resistance through downregulation of MDR1 and MRP5 gene expression.

The role of basic leucine zipper transcription factor E4BP4 in cancer: a review and update.

Mutations in the genes of tumor cells and the disorder of immune microenvironment are the main factors of tumor development. The sensitivity of tumor cells to chemotherapy drugs affect the treatment of tumor. Nuclear transcription factor E4BP4 is dysregulated in a variety of malignant tumors. It can suppress the transcription of NFKBIA, RASSF8, SOSTDC1, FOXO-induced genes (TRAIL, FAS, GADD45a and GADD45b) and Hepcidin, up-regulate RCAN1-1 and PRNP, activate mTOR and p38 in cancer cells. Also, E4BP4 can regulate tumor immune microenvironment. TGFb1/Smad3/E4BP4/ IFNγ axis in NK cells plays an important role in antitumor immunotherapy. Over expression of E4BP4 inhibited the development of Th17 cells by directly binding to the RORγt promoter. Moreover, recent studies have shown that E4BP4 inhibited the expression of multidrug resistance genes. In this review, we summarize the molecular mechanism of E4BP4 in cancer cellular process, the effects of E4BP4 in cancer immunotherapy and antitumor drug resistance, to provide theoretical basis for tumor treatment strategies targeting E4BP4.

Isolation and characterizations of multidrug-resistant human cancer cells by a biodegradable nano-sensor

Multidrug resistance (MDR) remains a significant challenge in cancer therapy, with inherent and acquired resistance distinct. While conventional drug selection processes enable the isolation of cancer cells with acquired multidrug resistance, identifying cancer cells with inherent drug resistance remains challenging. Herein, we proposed a molecular beacon (MB)-based strategy to identify and isolate the inherent MDR cancer cells. A lipid/PLGA core-shell nanoparticulate system (DNCP) was designed to deliver MB for intracellular MDR1 mRNA imaging. DNCP-MB – possess a surface potential of −8 mV and a size of 150 nm – demonstrated effective delivery of MB, remarkable selectivity towards the selected intracellular mRNA targets, and low cytotoxicity. Following DNCP transfection, fluorescence-activated cell sorting (FACS) was employed to differentiate MCF-7 cells into two distinct sub-populations: the Top 10 cells with a high level of MDR gene expression and the Bottom 10 cells with a low level of MDR gene expression, which represent inherent drug-resistant and non-drug-resistant cells, respectively. Intriguingly, we observed a positive correlation between elevated MDR1 mRNA expression and increased migration, enhanced proliferation rate, and tighter spheroid formation. Moreover, we conducted RNA sequencing analysis on the Top 10, Bottom 10, and MCF-7/ADR cells. The findings revealed a notable disparity in the gene ontology enrichment analysis of differentially expressed genes between the Top 10 and Bottom 10 cells when compared to the Bottom 10 and MCF-7/ADR cells. This novel approach provides a promising avenue for isolating inherent drug-resistant cells and holds significant potential in unraveling the mechanisms underlying inherent drug resistance.

Food wastes as a potential hotspot of antibiotic resistance: synergistic expression of multidrug resistance and ESBL genes confer antibiotic resistance to microbial communities.

This study investigated antibiotic resistance (ABR) and extended-spectrum ß-lactamases (ESBL) patterns in bacterial isolates collected from the dairy, hotel, meat, and canteen food waste samples. A total of 144 bacterial strains were collected and screened for resistance against 9 standard antibiotics belonging to three generations and ESBL production. The ABR profile of the bacterial isolates was observed against all four major antibiotic groups (aminoglycosides, β-lactams, quinolone, and others), where resistance against cefotaxime (> 70%) and methicillin (> 50%) was high. Though the ABR pattern of strains from dairy waste (> 50%) was high against first-generation antibiotics, the strains from meat waste (> 50%) showed considerable resistance against second- and third-generation antibiotics. ESBL-producing isolates were screened (> 60%, n = 144) through primary identification tests (combined disk test and double disk synergy tests) and further confirmed through Hexa G-minus 23 and 24 and MIC E-stripe following CLSI guidelines. Genes conferring ESBL resistance blaCTX-M, blaSHV, blaOXA, blaTEM, blaKPC genes and multidrug resistance (MDR) mexF gene were detected in the selected isolates with ABR and ESBL traits. Isolates with multidrug ABR and ESBL phenotype were further genotypically identified through 16s rRNA gene sequencing. The synergy of ABR was detected through the co-expression of ESBL and MDR in isolates with a high occurrence of ABR and ESBL. The results demonstrate the significance of food waste as a natural reservoir of ABR and ESBL-producing pathogens, highlighting the importance of resistance monitoring and its interventions.

The Influence of MDR1 Expression Regulated by miR-138 through TRPS1 Signaling Pathway on Multidrug Resistance of Osteosarcoma and Formation of Bacterial Infection Biofilm.

This study was to investigate the effect of microribonucleic acid (mi-RNA) on the resistance of human multidrug resistance gene 1 (MDR1) to osteosarcoma through the Trico-nasal finger syndrome 1 (TRPS1) pathway, as well as the effect of mi-RNA on biofilm formation. For this purpose, firstly, the expression of MDR1 and TRPS1 in osteosarcoma cells was detected by quantitative polymerase chain reaction (qPCR) technology. Moreover, the clinical paraffin sections of osteosarcoma cells were collected to explore the correlation between MDR1 and TRPS1. Then, both the MG-38 cells expressing and not expressing miR-138 were expanded. Afterward, a plasmid with a full-length clone of the TRPS1 antibody was applied to transfect the cells. Besides, Q-OCR was employed to detect the expression of TRPS1 and MDR1, and the expression of TRPS1 protein and P-glycoprotein (P-gp) was detected by Western blot (WB). The MTT method was adopted to detect the changes in the median lethal dose of doxorubicin and cisplatin in cells from each group. The well plate was used to establish an in vitro bacterial infection biofilm model, and the above two transfected cells were added during the model establishment process. Moreover, the formation of biofilm in the two groups was observed. The result of the paraffin biopsy was 33% (25/75) of mi-RNA, the positive rate of TRPS1 was 18.6%, and the Pearson correlation coefficient of the two was 0.477. Under mi-RNA interference, the TRPS1 and MDR1 of the three system cells were sharply reduced, and the trend of changes between the two was the same. The tolerance of the mi-RNA interference group to doxorubicin, cisplatin, paclitaxel and 5-fluorouracil decreased steeply, and the median lethal dose dropped, while the non-mi-RNA interference group showed the opposite trend. In addition, the number of colonies in the interference group was less sharp than that of the control group and the non-mi-RNA interference group. The conclusion was that mi-RNA could control the expression of MDR1 through the TRPS1 pathway, thus affecting the multi-drug resistance of osteosarcoma and also influencing the formation of bacterial biofilms.

Modulation of Doxorubicin Induced Expression of Multidrug Resistance Gene in Breast Cancer cells by Astaxanthin

Modulation of Doxorubicin Induced Expression of Multidrug Resistance Gene in Breast Cancer cells by Astaxanthin

Artemisinin alters disposition regularities of enrofloxacin and its metabolite ciprofloxacin in channel catfish (Ictalurus punetaus) following combined oral administration

The aim of this investigation was to explore the effect of artemisinin (ART) on pharmacokinetic (PK) and tissue distribution characteristics of enrofloxacin (ENR) and ciprofloxacin (CIP) in channel catfish following combined and single medicine. The channel catfish in ENR group were treated with ENR, and the fish in ENR-ART group were orally co-administrated with ENR and ART. ENR and CIP concentrations in channel catfish were determined using ultra performance liquid chromatography, and PK parameters for ENR and CIP were calculated by WinNonlin software. Moreover, the multi-drug resistance 1 (MDR1) gene expression and cytochrome P-450 3A (CYP 3A) enzyme activities in channel catfish liver were measured. The results showed that lower ENR and CIP levels were observed in ENR-ART group than that in ENR group, and similar regularities in PK parameters were also found that Cmax, AUC and MRT values in ENR group were all greater than those in ENR-ART group. Furthermore, higher MDR1 gene expression and CYP 3A enzyme activities in channel catfish liver were observed in ENR-ART group than those in ENR group. The present investigation indicates that ART can reduce the ENR concentrations, accelerate the excretion of ENR and decrease the antibacterial efficacy of ENR in channel catfish.

Polymolecular botanical drug of Orthosiphon stamineus extract (C5OSEW5050ESA) as a complementary therapy to overcome gemcitabine resistance in pancreatic cancer cells.

Gemcitabine remains the cornerstone of pancreatic cancer treatment, despite exhibiting a modest effect on patient survival due to the development of drug resistance. Nuvastatic™ polymolecular botanical drug Orthosiphon stamineus (O.stamineus) is a folklore Asian herbal medicine that is used for the treatment of a variety of ailments. However, little is known about the mechanism of actions of the Nuvastatic™ polymolecular botanical drug of O.stamineus as a complementary therapy in resistant pancreatic cancer. It is postulated that the proprietary O.stamineus extract formulation (ID: C5EOSEW5050ESA) in Nuvastatic™ may sensitise resistant pancreatic cancer cells to gemcitabine. This study was conducted to assess the cytotoxic activity and synergistic effects of C5EOSEW5050ESA in gemcitabine-resistant pancreatic cancer cells. The effects of C5EOSEW5050ESA treatment on cell viability, multidrug-resistant genes, epithelial-mesenchymal transition, cellular senescence, cell death, and Notch signalling pathway were evaluated in gemcitabine-resistant Panc-1cells. C5EOSEW5050ESA sensitised gemcitabine resistant cells towards C5EOSEW5050ESA-gemcitabine combination treatment by reducing the expression of multidrug-resistant genes and epithelial-mesenchymal transition markers in gemcitabine-resistant cells compared to the control group, possibly through the inhibition of Notch signalling. This study provides valuable insight into using C5EOSEW5050ESA as a potential complementary treatment for resistant pancreatic cancer.

Comparison of effects of aminosalicylic acid, glucocorticoids and immunosuppressive agents on the expression of multidrug-resistant genes in ulcerative colitis

To compare the effects of aminosalicylic acid, glucocorticoids and immunosuppressants on the expression levels of multidrug resistance genes in patients with ulcerative colitis (UC), with the aim of providing a theoretical and therapeutic basis for the diagnosis, treatment, and prevention of UC. Fresh colonic mucosal tissues or postoperative pathological biopsies from 148 UC patients were collected, and the distribution sites and morphology of P-glycoprotein (P-gp) were detected using immunohistochemical staining. RT-PCR was used to quantify the expression levels of multidrug resistance gene (MDR1) mRNA before and after the corresponding treatment, and the effects of aminosalicylic acid, glucocorticoids and immunosuppressive drugs on P-gp were compared. In addition, the effects of the three drugs on MDR1 mRNA were analyzed. Administration of 5-aminosalicylic acid (5-ASA) drugs did not correlate with MDR1 expression in UC, whereas administration of glucocorticoids and immunosuppressive drugs was positively correlated with MDR1 expression profile. The expression levels of MDR1 mRNA and its product P-gp were significantly upregulated in patients who did not respond to glucocorticoids and immunosuppressive drugs. 5-ASA had no effect on the expression levels of MDR1 and its product P-gp in patients with a confirmed diagnosis of UC. However, the use of glucocorticoids and immunosuppressants can increase the expression level of MDR1.

Multidimensional Quantitative Measurement of Cancer Chemoresistance through Differential ZIF-8 Nanoparticle Cellular Retention.

Chemoresistance of cancer cells is conventionally quantified by half-maximal inhibitory concentration (IC50) or multidrug resistance gene 1 (MDR1) values, but these metrics can only reflect the overall drug resistance level of a cancer cell line. Meanwhile, the multidimensional evaluation of both the heterogeneity in a cell line and the drug resistance degree of each cell still presents a daunting challenge. We report here that the cellular heterogeneity, cellular cross contamination, and the proportion of chemoresistant cancer cells can be visualized via flow cytometry through the differential cellular retention of fluorescent ZIF-8 nanoparticles. In addition, we show that the degree of drug resistance exhibited by each cell subpopulation can be quantified by differing fluorescence of the drug-resistant and drug-sensitive cells in the corresponding flow cytometry profile, and the quantified metric S is highly consistent with the MDR1 expression results. Importantly, this novel strategy is applicable to various cancer cell lines, thus demonstrating a universal diagnosis platform for multidimensional, quantitative, and highly efficient diagnosis of cancer chemoresistance.

Comparison of EMT-Related and Multi-Drug Resistant Gene Expression, Extracellular Matrix Production, and Drug Sensitivity in NSCLC Spheroids Generated by Scaffold-Free and Scaffold-Based Methods.

Multicellular 3D tumor models are becoming a powerful tool for testing of novel drug products and personalized anticancer therapy. Tumor spheroids, a commonly used 3D multicellular tumor model, more closely reproduce the tumor microenvironment than conventional 2D cell cultures. It should be noted that spheroids can be produced using different techniques, which can be subdivided into scaffold-free (SF) and scaffold-based (SB) methods. However, it remains unclear, to what extent spheroid properties depend on the method of their generation. In this study, we aimed to carry out a head-to-head comparison of drug sensitivity and molecular expression profile in SF and SB spheroids along with a monolayer (2D) cell culture. Here, we produced non-small cell lung cancer (NSCLC) spheroids based on human lung adenocarcinoma cell line A549. Drug sensitivity analysis of the tested cell cultures to five different chemotherapeutics resulted in IC50 (A549-SB) > IC50 (A549-SF) > IC50 (A549-2D) trend. It was found that SF and SB A549 spheroids displayed elevated expression levels of epithelial-to-mesenchymal transition (EMT) markers and proteins associated with drug resistance compared with the monolayer A549 cell culture. Enhanced drug resistance of A549-SB spheroids can be a result of larger diameters and elevated deposition of extracellular matrix (ECM) that impairs drug penetration into spheroids. Thus, the choice of the spheroid production method can influence the properties of the generated 3D cell culture and their drug resistance. This fact should be considered for correct interpretation of drug testing results.

Delphinidin induces autophagic flux blockage and apoptosis by inhibiting both multidrug resistance gene 1 and DEAD-box helicase 17 expressions in liver cancer cells.

To investigate the function and regulatory mechanisms of delphinidin in the treatment of hepatocellular carcinoma. HepG2 and HuH-7 cells were treated with different concentrations of delphinidin. Cell viability was analysed by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The cell autophagy and autophagic flux were analysed by LC3b-green fluorescent protein (GFP)-Adv and LC3b-GFP-monomeric red fluorescent protein-Adv transfected HepG2 and HuH-7 cells, respectively. Cell apoptosis was analysed by Hoechst33342 staining, terminal deoxynucleotidyl transferase dUTP nick end labeling staining and DNA laddering. Cell autophagy, apoptosis and survival related protein expressions were detected by Western blotting. After treatment with different concentrations of delphinidin, the cell survival rate was significantly decreased. Delphinidin could block the autophagic flux, resulting in a significant increase in autophagosomes, and led to an increase in cell apoptosis. The combined application of delphinidin and cisplatin could promote the antitumour effect and reduce the dose of cisplatin in tumour cells. Further mechanism studies reveal that delphinidin could inhibit the multidrug resistance gene 1 (MDR1) and the tumour-promoting transcription cofactor DEAD-box helicase 17 (DDX17) expression in tumour cells. Overexpression of DDX17 could reverse delphinidin's antitumor function in tumour cells. Delphinidin has a strong anti-tumour effect by inducing tumour cell autophagic flux blockage and apoptosis by inhibiting of both MDR1 and DDX17 expression.

Curcumin-loaded nanoparticles reversed radiotherapy-triggered enhancement of MDR1 expression of CNE-2 cells in nasopharyngeal carcinoma

This study explored the effect of nanoparticle-encapsulating curcumin on strongly expressed multidrug resistance gene 1 (MDR1) in a human low-differentiated nasopharyngeal carcinoma cell line (CNE-2). The curcumin/chitosan-deoxycholic acid nanoparticles were prepared, and cells received different treatments: radiotherapy, empty carrier, curcumin and curcumin-loaded nanoparticles, followed by analysis of cell survival using the clonogenic assay, apoptosis, MDR1 and miR-593 level. Cell survival fractions in the curcumin group and curcumin-loaded nanoparticles group were reduced significantly. Moreover, we observed a reduced cell survival fraction in the curcumin-loaded nanoparticles group (p < 0.05). Remarkably, higher apoptosis rates were observed in cells receiving curcumin or curcumin-loaded nanoparticles treatments compared with radiotherapy. Moreover, the curcumin-loaded nanoparticle treatment enhanced apoptosis (p<0.05). Furthermore, a decreased MDR1 level was denoted in curcumin group and curcumin-loaded nanoparticles group and a further reduced MDR1 expression in nanoparticles group (p < 0.05). A higher miR-593 expression was observed in the curcumin group and curcumin-loaded nanoparticles group with a relative higher level in nanoparticles group (p<0.05). MDR1 expression in inhibitor group was significantly strengthened (p<0.05). Curcumin that is encapsulated in nanoparticles exhibited a stronger radio sensitizing effect. Its combination with radiotherapy can effectively inhibit NPC tumor growth, and suppress MDR1 expression while enhancing miR-593. After retarding the miR-593, the MDR1 expression was intensified. The radio sensitizing effect of curcumin-loaded nanoparticles was regulated by miR-593 but not triggered by MDR1. The curcumin-loaded nanoparticles mediated enhanced expression of miR-593, which in turn inhibited the transcription and translation of MDR1 gene, thereby reducing the radio resistance of NPC and restraining the growth of NPC more effectively.

Nkx2.8 promotes chemosensitivity in bladder urothelial carcinoma via transcriptional repression of MDR1

Multidrug resistance gene 1 (MDR1), a key factor contributing to drug insensitivity, has been associated with treatment failure and poor prognoses in various cancers, including bladder urothelial carcinoma (UC). Here we show that positive Nkx2.8 expression was associated with better prognosis of UC patients received chemotherapy. Patients with positive Nkx2.8 expression had promising prognosis from adjuvant chemotherapy. Enforced expression of Nkx2.8 promotes drug sensitivity of UC cells. Mechanistic investigations showed that Nkx2.8 negatively regulated expression of MDR1 by binds directly to the MDR1 promoter and transcriptionally represses MDR1 expression. P-gp inhibitor reversed chemosensitivity inhibition by Nkx2.8 scilencing. In clinical UC specimens, expression of Nkx2.8 inversely correlated with P-gp expression, and UC patients with Nkx2.8 positivity and low P-gp expression displayed the best prognosis. Our findings uncovered a new mechanism of chemosensitivity in UC cells and proposing Nkx2.8-MDR1 axis as a novel candidate target for therapeutic intervention of UC.

RCCS Bioreactor-Based Modeled Microgravity Affects Gastric Cancer Cells and Improves the Chemotherapeutic Effect

(1) Background: The main purpose of the study was to determine whether altered gravity might alter cell viability, improve drug delivery and modulate the expression of drug resistance-related genes. (2) Methods: This study investigated the intracellular mechanisms activated by microgravity in human resistant and sensitive gastric cancer cells (EPG85-257 RDB) and (EPG85-257 P). We used a rotary cell culture system (RCCS) developed by NASA to expose cells to altered gravity. The antitumor potential of microgravity was simulated by the RCCS bioreactor, and its effectiveness was evaluated in sensitive cell lines compared to chemotherapy-resistant cells concerning drug-sensitive cancer cells. Microgravity with chemotherapy was estimated by the viability assay, cytoskeleton imaging, MDR (multidrug resistance) gene expression analysis, MTCO-1 (mitochondrially encoded cytochrome C oxidase I), and 8-OHdG immunocytochemical analysis. (3) Results: We found that altered gravity combined with doxorubicin was cytotoxic to cancer cells. Cells following simulated microgravity revealed decreased expression of genes related to drug resistance and increased DNA/RNA damage marker expression. Cytoskeleton evaluation demonstrated significant reorganization of F-actin fibers after exposure to changed gravity conditions. (4) Conclusions: Intracellular alterations caused by simulated microgravity can increase gastric cancer cells’ sensitivity to chemotherapy. We have obtained satisfactory results showing the correlation between altered gravity and MDR phenomena which seems promising in future therapeutic applications.

Synergistic combination of PMBA and 5-fluorouracil (5-FU) in targeting mutant KRAS in 2D and 3D colorectal cancer cells

β-Boswellic acid (β-BA), a potent NF-kB signaling pathway inhibitor, has shown synergistic anti-cancerous activity (NCT03149081, NCT00243022 and NCT02977936) in various clinical trials as complementary therapies. The study has been conducted to investigate the effect and efficacy of 2-pyridin-4-yl methylene β-boswellic acid (PMBA) and 5-Flourouracil (5-FU) in combination therapy for the treatment of KRAS mutant colon cancer. Analysis of isobologram showed synergistic combination index (CI > 1) of PMBA and 5-FU against the HCT-116G13D and SW-620G12V cell lines. The growth-inhibiting PMBA also caused apoptosis mediating effects with dose-dependent increase in caspase-3 activity, while inhibiting the formation of colonies in combination with 5-FU. As evident, PMBA affected colorectal 3D CSC properties including the ability to self-renew along with the expression of multi-drug resistance genes, viz., ABCB1, ABCC1 and ALDH1A1, ALDH1A2, ALDH1A3, ALDH3A1, and CSC markers like CD44, CD166, EPCAM, OCT-4, SOX-2, and NANOG compared with those in 2D model explaining the expression pattern of oncogenic KRASG13D, G12V mutation. When examined for plasma level of PMBA (20 mg) and PMBA+5-FU (20 + 40 mg), a time-dependent increase in the level of the drug (5-FU) was detected, indicating its absorption and bioavailability with excellent half-life of the PMBA for both routes of administration (IV and Oral), thereby indicating a new adjuvant therapy for KRAS mutant colon cancer.

Casein Kinase-1-Alpha Inhibitor (D4476) Sensitizes Microsatellite Instable Colorectal Cancer Cells to 5-Fluorouracil via Authophagy Flux Inhibition

Adjuvant chemotherapy with 5-fluorouracil (5-FU) does not improve survival of patients suffering from a form of colorectal cancer (CRC) characterized by high level of microsatellite instability (MSI-H). Given the importance of autophagy and multi-drug-resistant (MDR) proteins in chemotherapy resistance, as well as the role of casein kinase 1-alpha (CK1α) in the regulation of autophagy, we tested the combined effect of 5-FU and CK1α inhibitor (D4476) on HCT116 cells as a model of MSI-H colorectal cancer. To achieve this goal, the gene expression of Beclin1 and MDR genes, ABCG2 and ABCC3 were analyzed using quantitative real-time polymerase chain reaction. We used immunoblotting to measure autophagy flux (LC3, p62) and flow cytometry to detect apoptosis. Our findings showed that combination treatment with 5-FU and D4476 inhibited autophagy flux. Moreover, 5-FU and D4476 combination therapy induced G2, S and G1 phase arrests and it depleted mRNA of both cell proliferation-related genes and MDR-related genes (ABCG2, cyclin D1 and c-myc). Hence, our data indicates that targeting of CK1α may increase the sensitivity of HCT116 cells to 5-FU. To our knowledge, this is the first description of sensitization of CRC cells to 5-FU chemotherapy by CK1α inhibitor.Graphic abstract