Linking ABC transporters to the hallmarks of cancer

SNP's use as a potential chemotoxicity stratification tool in breast cancer: from bench to clinic

Breast cancer (BC) remains one of the most prevalent malignancies affecting women worldwide, necessitating ongoing research to improve treatment outcomes and minimize adverse effects associated with chemotherapy. This article explores the role of genetic variations, particularly single nucleotide polymorphisms (SNPs), in influencing the efficacy and toxicity of chemotherapeutic agents used in BC treatment. It highlights the impact of polymorphisms in drug metabolism and transport genes, such as UDP-glucuronosyltransferase 1A1 (UGT1A1), carbonyl reductase 1 (CBR1), and ATP-binding cassette multidrug transporter (ABCB1) on the risk of adverse effects, including cardiotoxicity and hematological toxicities. By identifying specific SNPs associated with drug response and toxicity, this research underscores the potential for personalized medicine approaches to optimize treatment regimens, enhance therapeutic efficacy, and minimize side effects in BC patients. The findings advocate for the integration of genetic screening in clinical practice to improve patient outcomes and tailor chemotherapy based on individual genetic profiles.

Dysregulation of cholesterol homeostasis in cancer pathogenesis

Cholesterol is a unique lipid for all mammalian cells, with important functions in membrane biogenesis and maintenance of proper membrane integrity and fluidity. Therefore, it plays an important role in cellular homeostasis. Dysregulation of cholesterol homeostasis is associated with various diseases in humans, including cardiovascular diseases, inflammatory diseases, neurodegenerative disorders, and cancers. In the tumor microenvironment, intrinsic and extrinsic cellular factors reprogram cholesterol metabolism and consequently promote tumorigenesis. Here, we summarize the current knowledge on molecular mechanisms and functional roles of cholesterol homeostasis and its dysregulation in regard to cancer pathogenesis. We also discuss the interplay of cholesterol metabolism and the ATP-binding cassette (ABC) proteins, highly conserved cellular transmembrane lipid transporters. An emerging role of lipid ABC transporters as potential prognostic tools for cancer progression and invasiveness is emphasized. Targeting both cholesterol metabolism and proteins associated with membrane cholesterol holds promise as a novel therapeutic strategy for cancer treatment.

Inhibition of ABCG2 by SCO-101 Enhances Chemotherapy Efficacy in Cancer

Chemotherapy resistance, particularly multidrug resistance (MDR), remains a significant barrier to effective cancer treatment, leading to high mortality rates. The development of novel therapeutic strategies targeting key molecular mechanisms to counteract drug resistance is thus an urgent clinical need. In this study, we evaluated the potential of the small molecule SCO-101 to restore chemotherapy sensitivity in drug-resistant cancer cells. Using in silico and in vitro models such as molecular docking, cell viability, colony formation, dye efflux, transporter assays and chemotherapy retention, we assessed the impact of SCO-101 on drug retention and response in several drug-resistant cancer cells. SCO-101 was found to inhibit the activity of breast cancer resistance protein (BCRP/ABCG2) and UDP Glucuronosyltransferase Family 1 Member A1 (UGT1A1), two key proteins involved in drug resistance by cellular drug excretion and drug metabolism. Our results demonstrate that inhibition of these proteins by SCO-101 leads to increased intracellular drug accumulation, enhancing the cytotoxic effects of chemotherapy agents. Additionally, we identified a strong correlation between high ABCG2 expression and MDR in non-drug-resistant models, where cells exhibiting elevated ABCG2 levels displayed chemotherapy resistance, which was effectively reversed by SCO-101 co-treatment. These findings highlight the therapeutic potential of SCO-101 in overcoming MDR by inhibiting drug efflux mechanisms and metabolism, thereby enhancing chemotherapy efficacy. SCO-101 is currently undergoing clinical trials as an orally administered drug and is considered a promising strategy for improving cancer treatment outcomes in patients with drug-resistant tumors.

Fecal profiling reveals a common microbial signature for pancreatic cancer in Finnish and Iranian cohorts

BACKGROUND

Pancreatic cancer (PC) presents a significant challenge in oncology because of its late-stage diagnosis and limited treatment options. The inadequacy of current screening methods has prompted investigations into stool-based assays and microbial classifiers as potential early detection markers. The gut microbiota composition of PC patients may be influenced by population differences, thereby impacting the accuracy of disease prediction. However, comprehensive profiling of the PC gut microbiota and analysis of these cofactors remain limited. Therefore, we analyzed the stool microbiota of 33 Finnish and 50 Iranian PC patients along with 35 Finnish and 34 Iranian healthy controls using 16S rRNA gene sequencing. We assessed similarities and differences of PC gut microbiota in both populations while considering sociocultural impacts and generated a statistical model for disease prediction based on microbial classifiers. Our aim was to expand the current understanding of the PC gut microbiota, discuss the impact of population differences, and contribute to the development of early PC diagnosis through microbial biomarkers.

RESULTS

Compared with healthy controls, PC patients presented reduced microbial diversity, with discernible microbial profiles influenced by factors such as ethnicity, demographics, and lifestyle. PC was marked by significantly higher abundances of facultative pathogens including Enterobacteriaceae, Enterococcaceae, and Fusobacteriaceae, and significantly lower abundances of beneficial bacteria. In particular, bacteria belonging to the Clostridia class, such as butyrate-producing Lachnospiraceae, Butyricicoccaceae, and Ruminococcaceae, were depleted. A microbial classifier for the prediction of pancreatic ductal adenocarcinoma (PDAC) was developed in the Iranian cohort and evaluated in the Finnish cohort, where it yielded a respectable AUC of 0.88 (95% CI 0.78, 0.97).

CONCLUSIONS

This study highlights the potential of gut microbes as biomarkers for noninvasive PC screening and the development of targeted therapies, emphasizing the need for further research to validate these findings in diverse populations. A comprehensive understanding of the role of the gut microbiome in PC could significantly enhance early detection efforts and improve patient outcomes.

Advancements of nanoscale drug formulations for combination treatment of colorectal cancer

Combination chemotherapy is widely utilized in treating colorectal cancer (CRC), particularly for patients who are ineligible for surgery or those with metastatic CRC (mCRC). While this therapeutic method has demonstrated efficacy in managing CRC and mCRC, its broader clinical application is limited due to the unique physical properties, mechanisms of action, and pharmacokinetics of different chemotherapeutic drugs. Consequently, achieving satisfactory treatment outcomes proves to be challenging. Nanotechnology has given rise to innovative drug systems that are precise, controllable, and highly efficient in drug delivery. These nanoscale drug delivery systems can integrate the advantageous aspects of various therapeutic modalities, including chemotherapy, gene therapy, and immunotherapy. This review aims to explain the application of nano-drug delivery system in the treatment of colorectal cancer. Through its unique physical/chemical properties and biological functions, it can solve the limitations of traditional therapy and achieve more accurate, efficient and safe treatment. The advantages/disadvantages, physical and chemical characteristics of various drug delivery systems are described in detail, and suggestions on selecting reasonable NDDSs according to different drug combination methods are given to achieve the best therapeutic effect. This review paper presents an exhaustive summary of the diverse range of drugs utilized in chemotherapy, in addition to outlining strategies for effectively integrating chemotherapy with other treatment modalities. Furthermore, it delves into the principle of selecting carriers for various drug combinations.

Spiroindoline quinazolinedione derivatives as inhibitors of P-glycoprotein: potential agents for overcoming multidrug resistance in cancer therapy

Multidrug resistance (MDR) presents a major challenge for effectiveness of chemotherapy. This study investigates the effectiveness of spiroindoline quinazolinediones in reversing MDR mediated by P-glycoprotein (P-gp) overexpression in cancer cells. A series of synthesized hybrid spiro[indoline-3,2'-quinazoline]-2,4'(3'H)-dione derivatives (compounds 5a-5l) were analyzed for their ability to enhance rhodamine 123 (Rhd123) accumulation in the MES-SA/DX5 cell line using flow cytometry. The MTT assay was also employed to evaluate the compounds' effectiveness in reversing drug resistance. Additionally, docking studies and molecular dynamics simulations were conducted to investigate the interaction of these compounds with the P-gp transporter. The Rhd123 accumulation assay in MDR cancer cells revealed that most compounds, in particular 5f, 5g, 5h, 5i, 5j, 5k, and 5l, exhibited significant potential as P-gp inhibitors. Among the tested derivatives, compounds 5g and 5l demonstrated the best effects, and increased Rhd123 accumulation up to 12.9 times compared to untreated cells. Additionally, compounds 5f through 5 l bearing methylbenzyl (5f), benzyl (5g), pentyl (5 ), p-bromobenzyl (5i), p-chlorobenzyl (5j), dichlorobenzyl (5k), and tert-butylbenzyl (5l) substituents on the isatin ring effectively restored sensitivity to doxorubicin at their non-toxic concentrations in resistant MES-SA/DX5 cells. Among these, compound 5l at 5 μM exhibited the highest inhibitory potential, and lowered doxorubicin's IC50 value 10.1 times compared to control. Moreover, in silico investigation identified the potential interactions of test compounds with critical residues of P-gp involved in its efflux function. Our study suggests that the synthesized spiroindoline quinazolinediones may have high potentials as agents capable of reversing MDR in cancer cells.

Metabolomic Characteristics of Aqueous Humor in Wet Age-Related Macular Degeneration and the Impact of Anti-VEGF Treatment

Purpose

To explore the alterations in metabolites of wet age-related macular degeneration (wAMD) by conducting metabolomics in aqueous humor from patients with wAMD and to assess the potential effects of anti-vascular endothelial growth factor (anti-VEGF) on these metabolites.

Methods

Metabolomic analysis was performed on the aqueous humor of 30 patients with wAMD receiving anti-VEGF treatments and 20 controls, via ultra-high performance liquid chromatography tandem mass spectrometry. The aqueous humor samples collected from untreated patients with wAMD were classified as the pre-wAMD group. Accordingly, the samples collected from patients with wAMD receiving one anti-VEGF treatment were designated as the post-wAMD group. Individuals were further classified into responders and nonresponders according to their reaction to the treatment. Principal component analysis, hierarchical cluster analysis, and the Kyoto Encyclopedia of Genes and Genomes annotation and enrichment analysis, were subsequently performed. Machine learning and receiver operating characteristic curve analyses were used to further analyze potential vital metabolites.

Results

Among the 1001 metabolites verified in the aqueous humor, 306 compounds separated patients with pre-wAMD from the control group, whereas 68 metabolites differentiated patients with post-wAMD and patients with pre-wAMD. Enrichment in metabolic pathways was noted in ABC transporters, thiamine metabolism, glycerophospholipid metabolism, mammalian target of rapamycin signaling pathway and tyrosine metabolism, and so on. Machine learning and receiver operating characteristic curves analysis suggested that δ-valerolactam could not only distinguish between patients with wAMD and the control group, but also differentiate between patients with post-wAMD and patients with pre-wAMD. Changes in acylcarnitine were observed in anti-VEGF responders with wAMD.

Conclusions

There were noticeable alterations in the aqueous humor of patients with wAMD involving many metabolites that are associated with ABC transporters, glycerophospholipid metabolism, and the mammalian target of rapamycin signaling pathway. It is possible that δ-valerolactam can be applied as a biomarker in wAMD.

c-MET tyrosine kinase inhibitors reverse drug resistance mediated by the ATP-binding cassette transporter B1 (ABCB1) in cancer cells

This study investigated the potential of MET kinase inhibitors, cabozantinib, crizotinib, and PHA665752, in reversing multidrug resistance (MDR) mediated by ABCB1 in cancer cells. The accumulation of the fluorescent probe, Rhodamine 123, was assessed using flow cytometry and fluorescence microscopy in MDR MES-SA/DX5 and parental cells. The growth inhibitory activity of MET inhibitors as monotherapies and in combination with chemotherapeutic drugs was evaluated by MTT assay. CalcuSyn software was used to analyze the combination index (CI) as an index of drug-drug interaction in combination treatments. Results showed that at concentrations of 5, and 25 μM, c-MET inhibitors significantly increased Rhodamine 123 accumulation in MDR cells, with ratios up to 17.8 compared to control cells, while exhibiting no effect in parental cells. Additionally, the combination of c-MET inhibitors with the chemotherapeutic agent doxorubicin synergistically enhanced cytotoxicity in MDR cells, as evidenced by combination index (CI) values of 0.54 ± 0.08, 0.69 ± 0.1, and 0.85 ± 0.07 for cabozantinib, crizotinib, and PHA665752, respectively. While all three c-MET inhibitors stimulated ABCB1 ATPase activity in different manners at certain concentrations, PHA-665752 suppressed it at high concentration. In silico analysis also suggested that the transmembrane domains (TMD) of ABCB1 transporters could be considered potential target for these agents. Our results suggest that c-MET inhibitors can serve as promising MDR reversal agents in ABCB1-medicated drug-resistant cancer cells.

Therapeutic and diagnostic applications of carbon nanotubes in cancer: recent advances and challenges

Carbon nanotubes (CNTs) are allotropes of carbon, composed of carbon atoms forming a tube-like structure. Their high surface area, chemical stability, and rich electronic polyaromatic structure facilitate their drug-carrying capacity. Therefore, CNTs have been intensively explored for several biomedical applications, including as a potential treatment option for cancer. By incorporating smart fabrication strategies, CNTs can be designed to specifically target cancer cells. This targeted drug delivery approach not only maximizes the therapeutic utility of CNTs but also minimizes any potential side effects of free drug molecules. CNTs can also be utilised for photothermal therapy (PTT) which uses photosensitizers to generate reactive oxygen species (ROS) to kill cancer cells, and in immunotherapeutic applications. Regarding the latter, for example, CNT-based formulations can preferentially target intra-tumoural regulatory T-cells. CNTs also act as efficient antigen presenters. With their capabilities for photoacoustic, fluorescent and Raman imaging, CNTs are excellent diagnostic tools as well. Further, metallic nanoparticles, such as gold or silver nanoparticles, are combined with CNTs to create nanobiosensors to measure biological reactions. This review focuses on current knowledge about the theranostic potential of CNT, challenges associated with their large-scale production, their possible side effects and important parameters to consider when exploring their clinical usage.

The neuroepithelial origin of ovarian carcinomas explained through an epithelial-mesenchymal-ectodermal transition enhanced by cisplatin

Acquired resistance to platinum-derived cytostatics poses major challenges in ovarian carcinoma therapy. In this work, we show a shift in the epithelial-mesenchymal transition (EMT) process towards an "ectodermal" conversion of ovarian carcinoma cells in response to cisplatin treatment, a progression we have termed epithelial-mesenchymal-ectodermal transition (EMET). EMET appears to occur via the classical EMT as judged by a) the downregulation of several epithelial markers and b) upregulation of Vimentin, accompanied by various embryonal transcription factors and, importantly, a plethora of neuronal markers, consistent with ectodermal differentiation. Moreover, we isolated cells from ovarian carcinoma cultures exhibiting a dual neural/stemness signature and multidrug resistance (MDR) phenotype. We also found that the epithelial cells differentiate from these neural/stem populations, indicating that the cell of origin in this tumor must in fact be a neural cell type with stemness features. Notably, some transcription factors like PAX6 and PAX9 were not localized in the nucleoplasm of these cells, hinting at altered nuclear permeability. In addition, the neuronal morphology was rapidly established when commercially available and primary ovarian carcinoma cells were cultured in the form of organoids. Importantly, we also identified a cell type in regular ovarian tissues, which possess similar neural/stemness features as observed in 2D or 3D cultures. The signature of this cell type is amplified in ovarian carcinoma tumors, suggesting a neuroepithelial origin of this tumor type. In conclusion, we propose that ovarian carcinomas harbor a small population of cells with an intrinsic neuronal/stemness/MDR phenotype, serving as the cradle from which ovarian carcinoma evolves.

Unraveling the secrets: Evolution of resistance mediated by membrane proteins

Membrane protein-mediated resistance is a multidisciplinary challenge that spans fields such as medicine, agriculture, and environmental science. Understanding its complexity and devising innovative strategies are crucial for treating diseases like cancer and managing resistant pests in agriculture. This paper explores the dual nature of resistance mechanisms across different organisms: On one hand, animals, bacteria, fungi, plants, and insects exhibit convergent evolution, leading to the development of similar resistance mechanisms. On the other hand, influenced by diverse environmental pressures and structural differences among organisms, they also demonstrate divergent resistance characteristics. Membrane protein-mediated resistance mechanisms are prevalent across animals, bacteria, fungi, plants, and insects, reflecting their shared survival strategies evolved through convergent evolution to address similar survival challenges. However, variations in ecological environments and biological characteristics result in differing responses to resistance. Therefore, examining these differences not only enhances our understanding of adaptive resistance mechanisms but also provides crucial theoretical support and insights for addressing drug resistance and advancing pharmaceutical development.

The BET inhibitor JQ1 suppresses tumor survival by ABCB5-mediated autophagy in uveal melanoma

Uveal melanoma (UM), the most common adult ocular tumor, is aggressive and resistant to treatment, posing threat to patients' lives. The novel, effective therapies and the exploration of chemosensitizer for UM are imperative. The anticancer efficacy was evaluated with and without JQ1 treatment or ABCB5 gene silencing or overexpression. RNA sequencing identified downstream effectors in JQ1-treated cells. Integrated analysis of The Cancer Genome Atlas data (TCGA) and immunohistochemistry (IHC) revealed the oncogenic role of ABCB5. Functional analyses of JQ1 and defective ABCB5 were conducted using flow cytometry, transmission electron microscopy (TEM), IHC and western blot. The effects of JQ1 were validated in a heterotopic tumor model derived from OCM-1 cells. JQ1 inhibited cell proliferation, migration and invasion, induced cell cycle arrest and promoted apoptosis. JQ1 also suppressed the survival of UM in heterotopic tumor model. RNA sequencing indicated that JQ1 down-regulated the expressions of ABCB5 and autophagy-related genes, which was confirmed in vitro and in vivo by western blot. ABCB5, a marker associated with cancer stem cells and chemo-resistance, exhibited heightened expression in UM tissues, linked to immune infiltration. Notably, disrupting ABCB5 expression impeded UM cell proliferation and interfered with autophagy. Moreover, the overexpression of ABCB5 promoted cell proliferation, migration and invasion, and rescued autophagy related gene expression. Of note, JQ1 enhanced the sensitivity of OCM-1 cells to chemotherapy. Thus JQ1 inhibits UM survival via ABCB5-mediated autophagy and enhances chemo-sensitivity, suggesting potential for BET-based approaches in UM clinical management.

ABCG2 Gene Expression in Non-Small Cell Lung Cancer

Background/Objectives: ATP-binding cassette subfamily G member 2 [ABCG2/breast cancer resistance protein (BCRP)] contributes to mechanisms of multidrug resistance (MDR) and is a marker of side population (SP) cells in human cancers. The primary objective of this study was to investigate the impact of ABCG2 gene expression on the non-small cell lung cancer (NSCLC) development, course of cancer disease, and patient prognosis using publicly available data. Obtained results were supplemented with assessment of ABCG2 expression in blood of NSCLC patients. Methods: The dataset of lung cancer was analyzed utilizing the TIMER 2.0, UALCAN, TNMplot, MEXPRESS, cBioPortal, MethSurv, KM Plotter, STRING, and ShinyGO 0.80 databases. Blood samples from 50 patients were assessed using the real-time PCR method. Results: The ABCG2 gene was expressed at a low level in NSCLC, and did not correlate with clinical aggressiveness of lung cancer. Higher ABCG2 expression improved overall survival, but only in LUAD. In addition, CpG sites located on the CpG island affecting the NSCLC patient's prognosis were indicated. In the case of our own laboratory results, the study did not reveal any changes in the ABCG2 expression levels in blood collected from patients at different time points during the diagnostic-therapeutic procedure. In the in silico analysis, most ABCG2 protein interactors were associated with the development of drug resistance. Conclusions: ABCG2 appears to have a particularly significant impact on the survival of patients with lung cancer and on the effect of immunotherapy related to immune cell infiltration. Presented findings may support personalized medicine strategies based on bioinformatics findings.

Targeting TREX1 Induces Innate Immune Response in Drug-Resistant Small-Cell Lung Cancer

Small-cell lung cancer (SCLC) is the most lethal type of lung cancer. Paradoxically, this tumor displays an initial exquisite response to chemotherapy; however, at relapse, the tumor is highly resistant to subsequent available therapies. Here, we report that the expression of three prime repair exonuclease 1 (TREX1) is strongly induced in chemoresistant SCLCs. Assay for transposase-accessible chromatin using sequencing and chromatin immunoprecipitation sequencing revealed a significant increase in chromatin accessibility and transcriptional activity of TREX1 gene locus in chemoresistant SCLCs. Analyses of human SCLC tumors and patient-derived xenografts (PDX) also showed an increase in TREX1 expression in postchemotherapy samples. TREX1 depletion caused the activation of cyclic GMP-AMP synthase stimulator of interferon gene pathway due to cytoplasmic accumulation of damage-associated double-stranded DNA, inducing immunogenicity and enhancing the sensitivity of drug-resistant cells to chemotherapy. These findings suggest TREX1 upregulation may partially contribute to the survival of resistant cells, and its inhibition may represent a promising therapeutic strategy to enhance antitumor immunity and potentiate the efficacy of chemotherapy and/or immunotherapy in chemoresistant SCLCs. Significance: In this study, we show that targeting TREX1 induces an innate immune response and resensitizes SCLC cells to chemotherapy, representing a promising novel target for "immunologically" cold tumors, such as SCLC.

Genetic factors in the pathogenesis of cardio-oncology

In recent years, with advancements in medicine, the survival period of patients with tumours has significantly increased. The adverse effects of tumour treatment on patients, especially cardiac toxicity, have become increasingly prominent. In elderly patients with breast cancer, treatment-related cardiovascular toxicity has surpassed cancer itself as the leading cause of death. Moreover, in recent years, an increasing number of novel antitumour drugs, such as multitargeted agents, antibody‒drug conjugates (ADCs), and immunotherapies, have been applied in clinical practice. The cardiotoxicity induced by these drugs has become more pronounced, leading to a complex and diverse mechanism of cardiac damage. The risks of unintended cardiovascular toxicity are increased by high-dose anthracyclines, immunotherapies, and concurrent radiation, in addition to traditional cardiovascular risk factors such as smoking, hypertension, diabetes, hyperlipidaemia, and obesity. However, these factors do not fully explain why only a subset of individuals experience treatment-related cardiac toxicity, whereas others with similar clinical features do not. Recent studies indicate that genetics play a significant role in susceptibility to the development of cardiovascular toxicity from cancer therapies. These genes are involved in drug metabolism, oxidative damage, cardiac dysfunction, and other processes. Moreover, emerging evidence suggests that epigenetics also plays a role in drug-induced cardiovascular toxicity. We conducted a review focusing on breast cancer as an example to help oncologists and cardiologists better understand the mechanisms and effects of genetic factors on cardiac toxicity. In this review, we specifically address the relationship between genetic alterations and cardiac toxicity, including chemotherapy-related genetic changes, targeted therapy-related genetic changes, and immune therapy-related genetic changes. We also discuss the role of epigenetic factors in cardiac toxicity. We hope that this review will improve the risk stratification of patients and enable therapeutic interventions that mitigate these unintended adverse consequences of life-saving cancer treatments.

The xenobiotic transporter ABCC4/MRP4 promotes epithelial mesenchymal transition in pancreatic cancer

The xenobiotic transporter ABCC4/MRP4 is highly expressed in pancreatic ductal adenocarcinoma (PDAC) and correlates with a more aggressive phenotype and metastatic propensity. Here, we show that ABCC4 promotes epithelial-mesenchymal transition (EMT) in PDAC, a hallmark process involving the acquisition of mesenchymal traits by epithelial cells, enhanced cell motility, and chemoresistance. Modulation of ABCC4 levels in PANC-1 and BxPC-3 cell lines resulted in the dysregulation of genes present in the EMT signature. Bioinformatic analysis on several cohorts including tumor samples, primary patient-derived cultured cells, patient-derived xenografts, and cell lines, revealed a positive correlation between ABCC4 expression and EMT markers. We also characterized the ABCC4 cistrome and identified four candidate clusters in the distal promoter and intron one that showed differential binding of pro-epithelial FOXA1 and pro-mesenchymal GATA2 transcription factors in low ABCC4-expressing HPAF-II and high ABCC4-expressing PANC-1 xenografts. HPAF-II xenografts showed exclusive binding of FOXA1, and PANC-1 xenografts exclusive binding of GATA2, at ABCC4 clusters, consistent with their low and high EMT phenotype respectively. Our results underscore ABCC4/MRP4 as a valuable prognostic marker and a potential therapeutic target to treat PDAC subtypes with prominent EMT features, such as the basal-like/squamous subtype, characterized by worse prognosis and no effective therapies.

P. S, C. E. A, Rajarajan S, Sahoo S, Mohan G, Jaikumar VS, Ramesh RS, B. S. S, Jolly MK, Maliekal TT, Prabhu JS. Elucidating the Role of MicroRNA-18a in Propelling a Hybrid Epithelial-Mesenchymal Phenotype and Driving Malignant Progression in ER-Negative Breast Cancer

Epigenetic alterations that lead to differential expression of microRNAs (miRNAs/miR) are known to regulate tumour cell states, epithelial-mesenchymal transition (EMT) and the progression to metastasis in breast cancer. This study explores the key contribution of miRNA-18a in mediating a hybrid E/M cell state that is pivotal to the malignant transformation and tumour progression in the aggressive ER-negative subtype of breast cancer. The expression status and associated effects of miR-18a were evaluated in patient-derived breast tumour samples in combination with gene expression data from public datasets, and further validated in in vitro and in vivo breast cancer model systems. The clinical relevance of the study findings was corroborated against human breast tumour specimens (n = 446 patients). The down-regulated expression of miR-18a observed in ER-negative tumours was found to drive the enrichment of hybrid epithelial/mesenchymal (E/M) cells with luminal attributes, enhanced traits of migration, stemness, drug-resistance and immunosuppression. Further analysis of the miR-18a targets highlighted possible hypoxia-inducible factor 1-alpha (HIF-1α)-mediated signalling in these tumours. This is a foremost report that validates the dual role of miR-18a in breast cancer that is subtype-specific based on hormone receptor expression. The study also features a novel association of low miR-18a levels and subsequent enrichment of hybrid E/M cells, increased migration and stemness in a subgroup of ER-negative tumours that may be attributed to HIF-1α mediated signalling. The results highlight the possibility of stratifying the ER-negative disease into clinically relevant groups by analysing miRNA signatures.

Nanoparticles for efficient drug delivery and drug resistance in glioma: New perspectives

Gliomas are the most common primary tumors of the central nervous system, with glioblastoma multiforme (GBM) having the highest incidence, and their therapeutic efficacy depends primarily on the extent of surgical resection and the efficacy of postoperative chemotherapy. The role of the intracranial blood-brain barrier and the occurrence of the drug-resistant gene O6-methylguanine-DNA methyltransferase have greatly limited the efficacy of chemotherapeutic agents in patients with GBM and made it difficult to achieve the expected clinical response. In recent years, the rapid development of nanotechnology has brought new hope for the treatment of tumors. Nanoparticles (NPs) have shown great potential in tumor therapy due to their unique properties such as light, heat, electromagnetic effects, and passive targeting. Furthermore, NPs can effectively load chemotherapeutic drugs, significantly reduce the side effects of chemotherapeutic drugs, and improve chemotherapeutic efficacy, showing great potential in the chemotherapy of glioma. In this article, we reviewed the mechanisms of glioma drug resistance, the physicochemical properties of NPs, and recent advances in NPs in glioma chemotherapy resistance. We aimed to provide new perspectives on the clinical treatment of glioma.