Identification of the metabolic alterations associated with the multidrug resistant phenotype in cancer and their intercellular transfer mediated by extracellular vesicles

Isoquinolinequinone N-oxides with diverging mechanisms of action induce collateral sensitivity against multidrug resistant cancer cells

Multidrug resistance (MDR) is a major challenge in cancer research. Collateral sensitizers, compounds that exploit the enhanced defense mechanisms of MDR cells as weaknesses, are a proposed strategy to overcome MDR. Our previous work reported the synthesis of two novel Isoquinolinequinone (IQQ) N-oxides that induce collateral sensitivity in MDR ABCB1-overexpressing non-small cell lung cancer (NSCLC) and colorectal cancer cells. Herein, we aimed to investigate underlying mechanisms of antitumor and collateral sensitivity activity of these compounds. We evaluated their effect on cancer cell viability, proliferation, cell cycle profile, and studied their cytotoxicity in non-tumorigenic cells. Their antitumor effect was further studied using NSCLC and colorectal cancer MDR spheroids. To understand underlying collateral sensitivity mechanisms, we assessed the effect on rhodamine-123 accumulation, ROS production, GSH/GSSG balance and expression of key proteins associated with metabolism and redox balance. Both compounds reduced the viability of MDR cells, as 2D cultures or as spheroids, without decreasing the growth of a human nontumorigenic cell line, and increased rhodamine-123 accumulation in MDR NCI-H460/R cells. Moreover, RK2 increased ROS, disrupted GSH balance, and altered expression of proteins associated with oxidative stress protection, particularly in NCI-H460/R cells. The collateral sensitivity effect of RK3 could not be attributed to redox balance disruption, but increased IDH1 expression following treatment suggests a potential metabolic shift in MDR cells. These findings highlight RK2 and RK3 as promising candidates for next stages of drug development. Their distinct mechanisms of action could lead to therapeutic solutions for MDR-related cancers, specifically linked to ABCB1 overexpression.

LB-100 Enhances Drugs Efficacy Through Inhibition of P-Glycoprotein Expression in Multidrug-Resistant Glioblastoma and Non-Small Cell Lung Carcinoma Cellular Models

Background/Objectives: This study explores the potential of LB-100 (a protein phosphatase 2A-PP2A inhibitor) combined with adavosertib (a WEE1 kinase inhibitor) and doxorubicin (DOX), to overcome multidrug resistance (MDR) in cancer cells and enhance treatment efficacy. Methods: We evaluated LB-100 combinations with adavosertib and DOX in patient-derived glioblastoma and non-small cell lung carcinoma cells (NSCLCs) using a real-time cell analyzer. Effectiveness was also assessed through immunofluorescence assay, and interactions were analyzed via SynergyFinder+. We also examined P-glycoprotein (P-gp) expression and drug resistance genes' expression in MDR glioblastoma and NSCLCs after LB-100 treatment, as well as LB-100 sensitizing effect on DOX and DOX accumulation. Results: LB-100 significantly boosts the effectiveness of adavosertib and DOX after multiple applications. It also enhances these drugs' cytotoxicity in a single application without acting synergistically. Additionally, LB-100 reduces P-gp expression in MDR glioblastoma and NSCLCs, sensitizing them to DOX and increasing its accumulation. Conclusions: LB-100 enhances the effectiveness of drugs against MDR cancer cells, presenting a promising strategy to overcome drug resistance in glioblastoma and NSCLCs through P-gp modulation.

Exercise-induced extracellular vesicles in reprogramming energy metabolism in cancer

Cancer is caused by complex interactions between genetic, environmental, and lifestyle factors, making prevention strategies, including exercise, a promising avenue for intervention. Physical activity is associated with reduced cancer incidence and progression and systemic anti-cancer effects, including improved tumor suppression and prolonged survival in preclinical models. Exercise impacts the body's nutrient balance and stimulates the release of several exercise-induced factors into circulation. The mechanisms of how exercise modulates cancer energy metabolism and the tumor microenvironment through systemic effects mediated, in part, by extracellular vesicles (EVs) are still unknown. By transferring bioactive cargo such as miRNAs, proteins and metabolites, exercise-induced EVs may influence cancer cells by altering glycolysis and oxidative phosphorylation, potentially shifting metabolic plasticity - a hallmark of cancer. This short review explores the roles of EVs in cancer as mediators to reprogram cellular energy metabolism through exchanging information inside the tumor microenvironment, influencing immune cells, fibroblast and distant cells. Considering this knowledge, further functional studies into exercise-induced EVs and cellular energy production pathways could inform more specific exercise interventions to enhance cancer therapy and improve patient outcomes.

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.

Evaluation of the effect of GSK-3β on liver cancer based on the PI3K/AKT pathway

The PI3K/AKT/GSK-3β signaling pathway plays a pivotal role in numerous physiological and pathological processes, including cell proliferation, apoptosis, differentiation, and metabolic regulation. Aberrant activation of the PI3K/AKT pathway is intricately linked to development of tumor. GSK-3β, belonging to the serine/threonine protein kinase family, is crucial in the pathogenesis of liver cancer. As a key rate-limiting enzyme in the glucose metabolism pathway, GSK-3β significantly impacts the growth, proliferation, metastasis, and apoptosis of liver cancer cells. It is also implicated in chemotherapy resistance. Elevated expression of GSK-3β diminishes the sensitivity of liver cancer cells to chemotherapeutic agents, thereby playing a substantial role in the development of drug resistance. Consequently, targeting of GSK-3β, particularly within the PI3K/AKT signaling pathway, is regarded as a promising therapeutic strategy for liver cancer. The precise identification and subsequent modulation of this pathway represent a substantial potential for innovative clinical interventions in the management of liver cancer.

Multidrug-Resistant Profiles in Non-Small Cell Lung Carcinoma Patient-Derived Cells: Implications for Personalized Approaches with Tyrosine Kinase Inhibitors

The impact of tyrosine kinase inhibitors (TKIs) on multidrug resistance (MDR) in non-small cell lung carcinoma (NSCLC) is a critical aspect of cancer therapy. While TKIs effectively target specific signaling pathways of cancer cells, they can also act as substrates for ABC transporters, potentially triggering MDR. The aim of our study was to evaluate the response of 17 patient-derived NSCLC cultures to 10 commonly prescribed TKIs and to correlate these responses with patient mutational profiles. Using an ex vivo immunofluorescence assay, we analyzed the expression of the MDR markers ABCB1, ABCC1, and ABCG2, and correlated these data with the genetic profiles of patients for a functional diagnostic approach. NSCLC cultures responded differently to TKIs, with erlotinib showing good efficacy regardless of mutation burden or EGFR status. However, the modulation of MDR mechanisms by erlotinib, such as increased ABCG2 expression, highlights the challenges associated with erlotinib treatment. Other TKIs showed limited efficacy, highlighting the variability of response in NSCLC. Genetic alterations in signaling pathways associated with drug resistance and sensitivity, including TP53 mutations, likely contributed to the variable responses to TKIs. The relationships between ABC transporter expression, gene alterations, and response to TKIs did not show consistent patterns. Our results suggest that in addition to mutational status, performing functional sensitivity screening is critical for identifying appropriate treatment strategies with TKIs. These results underscore the importance of considering drug sensitivity, off-target effects, MDR risks, and patient-specific genetic profiles when optimizing NSCLC treatment and highlight the potential for personalized approaches, especially in early stages.

Chemosensitizing effect of pentoxifylline in sensitive and multidrug-resistant non-small cell lung cancer cells

Aim: Multidrug resistance (MDR) is frequent in non-small cell lung cancer (NSCLC) patients, which can be due to its fibrotic stroma. This work explores the combination of pentoxifylline, an anti-fibrotic and chitinase 3-like-1 (CHI3L1) inhibitor drug, with conventional chemotherapy to improve NSCLC treatment. Methods: The effect of pentoxifylline in the expression levels of P-glycoprotein (P-gp), CHI3L1 and its main downstream proteins, as well as on cell death, cell cycle profile, and P-gp activity was studied in two pairs of sensitive and MDR counterpart NSCLC cell lines (NCI-H460/NCI-H460/R and A549/A549-CDR2). Association studies between CHI3L1 gene expression and NSCLC patients' survival were performed using The Cancer Genome Atlas (TCGA) analysis. The sensitizing effect of pentoxifylline to different drug regimens was evaluated in both sensitive and MDR NSCLC cell lines. The cytotoxicity of the drug combinations was assessed in MCF10A non-tumorigenic cells. Results: Pentoxifylline slightly decreased the expression levels of CHI3L1, β-catenin and signal transducer and activator of transcription 3 (STAT3), and caused a significant increase in the G1 phase of the cell cycle in both pairs of NSCLC cell lines. A significant increase in the % of cell death was observed in the sensitive NCI-H460 cell line. TCGA analysis revealed that high levels of CHI3L1 are associated with low overall survival (OS) in NSCLC patients treated with vinorelbine. Moreover, pentoxifylline sensitized both pairs of sensitive and MDR NSCLC cell lines to the different drug regimens, without causing significant toxicity to non-tumorigenic cells. Conclusion: This study suggests the possibility of combining pentoxifylline with chemotherapy to increase NSCLC therapeutic response, even in cases of MDR.

Utilizing non-coding RNA-mediated regulation of ATP binding cassette (ABC) transporters to overcome multidrug resistance to cancer chemotherapy

Multidrug resistance (MDR) is one of the primary factors that produces treatment failure in patients receiving cancer chemotherapy. MDR is a complex multifactorial phenomenon, characterized by a decrease or abrogation of the efficacy of a wide spectrum of anticancer drugs that are structurally and mechanistically distinct. The overexpression of the ATP-binding cassette (ABC) transporters, notably ABCG2 and ABCB1, are one of the primary mediators of MDR in cancer cells, which promotes the efflux of certain chemotherapeutic drugs from cancer cells, thereby decreasing or abolishing their therapeutic efficacy. A number of studies have suggested that non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), play a pivotal role in mediating the upregulation of ABC transporters in certain MDR cancer cells. This review will provide updated information about the induction of ABC transporters due to the aberrant regulation of ncRNAs in cancer cells. We will also discuss the measurement and biological profile of circulating ncRNAs in various body fluids as potential biomarkers for predicting the response of cancer patients to chemotherapy. Sequence variations, such as alternative polyadenylation of mRNA and single nucleotide polymorphism (SNPs) at miRNA target sites, which may indicate the interaction of miRNA-mediated gene regulation with genetic variations to modulate the MDR phenotype, will be reviewed. Finally, we will highlight novel strategies that could be used to modulate ncRNAs and circumvent ABC transporter-mediated MDR.

Inhibition of multidrug-resistant MCF-7 breast cancer cells with combinations of clinical drugs and resin glycosides from Operculina hamiltonii

The jalap roots, Operculina hamiltonii D.F. Austin & Staples (Convolvulaceae), are extensively commercialized as a depurative and laxative remedy in traditional medicine of the north and northeast regions of Brazil. The purification by recycling HPLC and structure elucidation of three new acyl sugars or resin glycosides are described here from a commercial product made of powdered roots. Three macrocyclic structures of a tetrasaccharide of (11S)-hydroxyhexadecanoic acid, operculinic acid C (1), the undescribed hamiltonins II and III (3 and 4), in addition to the known batatinoside III (5), presented a diastereoisomeric relationship as one residue of n-dodecanoic acid esterified the oligosaccharide core on a different position in each compound. Furthermore, hamiltonin IV (6) was characterized as an ester-type homodimer of acylated operculinic acid C with the same substitution pattern identified in hamiltonins II (3) and III (4) for each of the dimer subunits. All the isolated resin glycosides did not display any intrinsic cytotoxicity (IC50 > 25 μM). However, a combination of the individual isolated compounds 3-6 (1-50 μM) demonstrated an enhancement of cytotoxic effects with sublethal doses of vinblastine and podophyllotoxin (0.003 μM) in multidrug-resistant breast carcinoma epithelial cells (MCF-7/Vin).

Role of exosomes in transferring chemoresistance through modulation of cancer glycolytic cell metabolism

Chemoresistance constitute a major obstacle in cancer treatment, leading to limited options and decreased patient survival. Recent studies have revealed a novel mechanism of chemoresistance acquisition: the transfer of information via exosomes, small vesicles secreted by various cells. Exosomes play a crucial role in intercellular communication by carrying proteins, nucleic acids, and metabolites, influencing cancer cell behavior and response to treatment. One crucial mechanism of resistance is cancer metabolic reprogramming, which involves alterations in the cellular metabolic pathways to support the survival and proliferation of drug-resistant cancer cells. This metabolic reprogramming often includes increased glycolysis, providing cancer cells with the necessary energy and building blocks to evade the effects of chemotherapy. Notably, exosomes have been found to transport glycolytic enzymes, as identified in proteomic profiling, leading to the reprogramming of metabolic pathways, facilitating altered glucose metabolism and increased lactate production. As a result, they profoundly impact the tumor microenvironment, promoting tumor progression, survival, immune evasion, and drug resistance.Understanding the complexities of such exosome-mediated cell-to-cell communication might open new therapeutic avenues and facilitate biomarker development in managing cancers characterized by aggressive glycolytic features. Moreover, given the intricate nature of metabolic abnormalities combining future exosome-based-targeted therapies with existing treatments like chemotherapy, immunotherapy, and targeted therapies holds promise for achieving synergistic effects to overcome resistance and improve cancer treatment outcomes.

The role of Extracellular Vesicles in glycolytic and lipid metabolic reprogramming of cancer cells: Consequences for drug resistance

In order to adapt to a higher proliferative rate and an increased demand for energy sources, cancer cells rewire their metabolic pathways, a process currently recognized as a hallmark of cancer. Even though the metabolism of glucose is perhaps the most discussed metabolic shift in cancer, lipid metabolic alterations have been recently recognized as relevant players in the growth and proliferation of cancer cells. Importantly, some of these metabolic alterations are reported to induce a drug resistant phenotype in cancer cells. The acquisition of drug resistance traits severely hinders cancer treatment, being currently considered one of the major challenges of the oncological field. Evidence suggests that Extracellular Vesicles (EVs), which play a crucial role in intercellular communication, may act as facilitators of tumour progression, survival and drug resistance by modulating several aspects involved in the metabolism of cancer cells. This review aims to gather and discuss relevant data regarding metabolic reprograming in cancer, particularly involving the glycolytic and lipid alterations, focusing on its influence on drug resistance and highlighting the relevance of EVs as intercellular mediators of this process.

Fibroblasts in pancreatic cancer: molecular and clinical perspectives

Pancreatic stellate cells (PSCs) and cancer-associated fibroblasts (CAFs) are highly abundant cells in the pancreatic tumor microenvironment (TME) that modulate desmoplasia. The formation of a dense stroma leads to immunosuppression and therapy resistance that are major causes of treatment failure in pancreatic ductal adenocarcinoma (PDAC). Recent evidence suggests that several subpopulations of CAFs in the TME can interconvert, explaining the dual roles (antitumorigenic and protumorigenic) of CAFs in PDAC and the contradictory results of CAF-targeted therapies in clinical trials. This highlights the need to clarify CAF heterogeneity and their interactions with PDAC cells. This review focuses on the communication between activated PSCs/CAFs and PDAC cells, as well as on the mechanisms underlying this crosstalk. CAF-focused therapies and emerging biomarkers are also outlined.

Nanocarriers overcoming biological barriers induced by multidrug resistance of chemotherapeutics in 2D and 3D cancer models

Multidrug resistance (MDR) is currently a big challenge in cancer therapy and limits its success in several patients. Tumors use the MDR mechanisms to colonize the host and reduce the efficacy of chemotherapeutics that are injected as single agents or combinations. MDR mechanisms are responsible for inactivation of drugs and formbiological barriers in cancer like the drug efflux pumps, aberrant extracellular matrix, hypoxic areas, altered cell death mechanisms, etc. Nanocarriers have some potential to overcome these barriers and improve the efficacy of chemotherapeutics. In fact, they are versatile and can deliver natural and synthetic biomolecules, as well as RNAi/DNAi, thus providing a controlled release of drugs and a synergistic effect in tumor tissues. Biocompatible and safe multifunctional biopolymers, with or without specific targeting molecules, modify the surface and interface properties of nanocarriers. These modifications affect the interaction of nanocarriers with cellular models as well as the selection of suitable models for in vitro experiments. MDR cancer cells, and particularly their 2D and 3D models, in combination with anatomical and physiological structures of tumor tissues, can boost the design and preparation of nanomedicines for anticancer therapy. 2D and 3D cancer cell cultures are suitable models to study the interaction, internalization, and efficacy of nanocarriers, the mechanisms of MDR in cancer cells and tissues, and they are used to tailor a personalized medicine and improve the efficacy of anticancer treatment in patients. The description of molecular mechanisms and physio-pathological pathways of these models further allow the design of nanomedicine that can efficiently overcome biological barriers involved in MDR and test the activity of nanocarriers in 2D and 3D models of MDR cancer cells.

Detection of Measurable Residual Disease Biomarkers in Extracellular Vesicles from Liquid Biopsies of Multiple Myeloma Patients-A Proof of Concept

Monitoring measurable residual disease (MRD) is crucial to assess treatment response in Multiple Myeloma (MM). Detection of MRD in peripheral blood (PB) by exploring Extracellular Vesicles (EVs), and their cargo, would allow frequent and minimally invasive monitoring of MM. This work aims to detect biomarkers of MRD in EVs isolated from MM patient samples at diagnosis and remission and compare the MRD-associated content between BM and PB EVs. EVs were isolated by size-exclusion chromatography, concentrated by ultrafiltration, and characterized according to their size and concentration, morphology, protein concentration, and the presence of EV-associated protein markers. EVs from healthy blood donors were used as controls. It was possible to isolate EVs from PB and BM carrying MM markers. Diagnostic samples had different levels of MM markers between PB and BM paired samples, but no differences between PB and BM were found at remission. EVs concentration was lower in the PB of healthy controls than of patients, and MM markers were mostly not detected in EVs from controls. This study pinpoints the potential of PB EVs from MM remission patients as a source of MM biomarkers and as a non-invasive approach for monitoring MRD.

Establishing and characterizing a novel doxorubicin-resistant acute myeloid leukaemia cell line

Drug resistance is a major setback in cancer treatment, thus models to study its mechanisms are needed. Our work aimed to establish and characterize a resistant cell line from a sensitive acute myeloid leukaemia (AML) cell line - HL60 - by treating the sensitive cells with increasing concentrations of doxorubicin. We confirmed (cell viability assays) that the established subline, HL60-CDR, was resistant to doxorubicin for at least 30 days without drug treatment. The HL60-CDR cells were also resistant to three other drugs (cisplatin, etoposide and daunorubicin), exhibiting a multidrug resistant (MDR) profile. We verified (Western Blotting) that the MDR cells do not express drug efflux pumps, nor present altered expression of apoptotic proteins, when compared with the parental cell line. HL60-CDR cells presented alterations in the cell cycle profile, and in the expression levels of proteins involved in DNA repair mechanisms and drug metabolism, when compared with their drug sensitive counterpart. Proteomic analysis revealed that HL60-CDR cells presented an upregulation of proteins involved in oncogenic pathways, such as TSC2, PDPK1, Annexin A2, among others. Overall, we established an AML MDR subline - HL60-CDR - which presents several resistance mechanisms, providing an in vitro model to test new compounds to circumvent MDR in AML.

Detachment of Hexokinase II From Mitochondria Promotes Collateral Sensitivity in Multidrug Resistant Chronic Myeloid Leukemia Cells

Chronic Myeloid Leukemia is a neoplastic disease characterized by the abnormal expansion of hematopoietic cells with compromised functions. Leukemic cells often display a multidrug resistance phenotype, enabling them to evade a number of structurally unrelated cytotoxic compounds. One of those mechanisms relies on the high expression of efflux transporters, such as the ABC proteins, whose activity depends on the hydrolysis of ATP to reduce intracellular drug accumulation. In the present work, we employed a well-known erythroleukemia cell line, K562, and a multidrug resistant derivative cell, FEPS, to evaluate how hexokinase II, a key regulator for the rate-limiting step glycolysis, contributes to the establishment of the multidrug resistance phenotype. We found that multidrug resistant cells primarily resort to glycolysis to generate ATP. Clotrimazole reduced the expression of mitochondrial hexokinase II, which destabilized bioenergetic parameters such as reactive oxygen species production, ATP, and glutathione levels on multidrug resistant cells. This impaired the activity of ABCC1, leading to increased drug accumulation and cell death. In summary, we propose that decoupling of hexokinase II from the mitochondria emerges as a promising strategy to generate collateral sensitivity and aid in the management of chronic myeloid leukemia in chemotherapy-refractory patients.

"Cells-to-cDNA on Chip": Phenotypic Assessment and Gene Expression Analysis from Live Cells in Nanoliter Volumes Using Droplet Microarrays

In vitro cell-based experiments are particularly important in fundamental biological research. Microscopy-based readouts to identify cellular changes in response to various stimuli are a popular choice, but gene expression analysis is essential to delineate the underlying molecular dynamics in cells. However, cell-based experiments often suffer from interexperimental variation, especially while using different readout methods. Therefore, establishment of platforms that allow for cell screening, along with parallel investigations of morphological features, as well as gene expression levels, is crucial. The droplet microarray (DMA) platform enables cell screening in hundreds of nanoliter droplets. In this study, a "Cells-to-cDNA on Chip" method is developed enabling on-chip mRNA isolation from live cells and conversion to cDNA in individual droplets of 200 nL. This novel method works efficiently to obtain cDNA from different cell numbers, down to single cell per droplet. This is the first established miniaturized on-chip strategy that enables the entire course of cell screening, phenotypic microscopy-based assessments along with mRNA isolation and its conversion to cDNA for gene expression analysis by real-time PCR on an open DMA platform. The principle demonstrated in this study sets a beginning for myriad of possible applications to obtain detailed information about the molecular dynamics in cultured cells.

Single cell mass spectrometry studies reveal metabolomic features and potential mechanisms of drug-resistant cancer cell lines

Irinotecan (Iri) is a key drug to treat metastatic colorectal cancer, but its clinical activity is often limited by de novo and acquired drug resistance. Studying the underlying mechanisms of drug resistance is necessary for developing novel therapeutic strategies. In this study, we used both regular and irinotecan-resistant (Iri-resistant) colorectal cell lines as models, and performed single cell mass spectrometry (SCMS) metabolomics studies combined with analyses from cytotoxicity assay, western blot, flow cytometry, quantitative real-time polymerase chain reaction (qPCR), and reactive oxygen species (ROS). Our SCMS results indicate that Iri-resistant cancer cells possess higher levels of unsaturated lipids compared with the regular cancer cells. In addition, multiple protein biomarkers and their corresponding mRNAs of colon cancer stem cells are overexpressed in Iri-resistance cells. Particularly, stearoyl-CoA desaturase 1 (SCD1) is upregulated with the development of drug resistance in Iri-resistant cells, whereas inhibiting the activity of SCD1 efficiently increase their sensitivity to Iri treatment. In addition, we demonstrated that SCD1 directly regulates the expression of ALDH1A1, which contributes to the cancer stemness and ROS level in Iri-resistant cell lines.

The Role of Extracellular Vesicles in Metabolic Reprogramming of the Tumor Microenvironment

The tumor microenvironment (TME) includes a network of cancerous and non-cancerous cells, together with associated blood vessels, the extracellular matrix, and signaling molecules. The TME contributes to cancer progression during various phases of tumorigenesis, and interactions that take place within the TME have become targets of focus in cancer therapy development. Extracellular vesicles (EVs) are known to be conveyors of genetic material, proteins, and lipids within the TME. One of the hallmarks of cancer is its ability to reprogram metabolism to sustain cell growth and proliferation in a stringent environment. In this review, we provide an overview of TME EV involvement in the metabolic reprogramming of cancer and stromal cells, which favors cancer progression by enhancing angiogenesis, proliferation, metastasis, treatment resistance, and immunoevasion. Targeting the communication mechanisms and systems utilized by TME-EVs is opening a new frontier in cancer therapy.

Pioneer Role of Extracellular Vesicles as Modulators of Cancer Initiation in Progression, Drug Therapy, and Vaccine Prospects

Cancer is one of the leading diseases, causing deaths worldwide. Nearly 10 million deaths were reported in 2020 due to cancer alone. Several factors are involved in cancer progressions, such as lifestyle and genetic characteristics. According to a recent report, extracellular vesicles (EVs) are involved in cancer initiation, progression, and therapy failure. EVs can play a major role in intracellular communication, the maintenance of tissue homeostasis, and pathogenesis in several types of diseases. In a healthy person, EVs carry different cargoes, such as miRNA, lncRNA etc., to help other body functions. On the other hand, the same EV in a tumor microenvironment carries cargoes such as miRNA, lncRNA, etc., to initiate or help cancer progression at various stages. These stages may include the proliferation of cells and escape from apoptosis, angiogenesis, cell invasion, and metastasis, reprogramming energy metabolism, evasion of the immune response, and transfer of mutations. Tumor-derived EVs manipulate by altering normal functions of the body and affect the epigenetics of normal cells by limiting the genetic makeup through transferring mutations, histone modifications, etc. Tumor-derived EVs also pose therapy resistance through transferring drug efflux pumps and posing multiple drug resistances. Such EVs can also help as biomarkers for different cancer types and stages, which ultimately help with cancer diagnosis at early stages. In this review, we will shed light on EVs' role in performing normal functions of the body and their position in different hallmarks of cancer, in altering the genetics of a normal cell in a tumor microenvironment, and their role in therapy resistance, as well as the importance of EVs as diagnostic tools.

Different Ability of Multidrug-Resistant and -Sensitive Counterpart Cells to Release and Capture Extracellular Vesicles

Cancer multidrug resistance (MDR) is one of the main challenges for cancer treatment efficacy. MDR is a phenomenon by which tumor cells become resistant to several unrelated drugs. Some studies have previously described the important role of extracellular vesicles (EVs) in the dissemination of a MDR phenotype. EVs’ cargo may include different players of MDR, such as microRNAS and drug-efflux pumps, which may be transferred from donor MDR cells to recipient drug-sensitive counterparts. The present work aimed to: (i) compare the ability of drug-sensitive and their MDR counterpart cells to release and capture EVs and (ii) study and relate those differences with possible distinct fate of the endocytic pathway in these counterpart cells. Our results showed that MDR cells released more EVs than their drug-sensitive counterparts and also that the drug-sensitive cells captured more EVs than their MDR counterparts. This difference in the release and capture of EVs may be associated with differences in the endocytic pathway between drug-sensitive and MDR cells. Importantly, manipulation of the recycling pathway influenced the response of drug-sensitive cells to doxorubicin treatment.

Characterising Alzheimer's disease through integrative NMR- and LC-MS-based metabolomics

Background

Alzheimer's Disease (AD) is a complex and multifactorial disease and novel approaches are needed to illuminate the underlying pathology. Metabolites comprise the end-product of genes, transcripts, and protein regulations and might reflect disease pathogenesis. Blood is a common biofluid used in metabolomics; however, since extracellular vesicles (EVs) hold cell-specific biological material and can cross the blood-brain barrier, their utilization as biological material warrants further investigation. We aimed to investigate blood- and EV-derived metabolites to add insigts to the pathological mechanisms of AD.

Methods

Blood samples were collected from 10 AD and 10 Mild Cognitive Impairment (MCI) patients, and 10 healthy controls. EVs were enriched from plasma using 100,000×g, 1 h, 4 °C with a wash. Metabolites from serum and EVs were measured using liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) spectroscopy. Multivariate and univariate analyses were employed to identify altered metabolites in cognitively impaired individuals.

Results

While no significant EV-derived metabolites were found differentiating patients from healthy individuals, six serum metabolites were found important; valine (p = 0.001, fold change, FC = 0.8), histidine (p = 0.001, FC = 0.9), allopurinol riboside (p = 0.002, FC = 0.2), inosine (p = 0.002, FC = 0.3), 4-pyridoxic acid (p = 0.006, FC = 1.6), and guanosine (p = 0.004, FC = 0.3). Pathway analysis revealed branched-chain amino acids, purine and histidine metabolisms to be downregulated, and vitamin B6 metabolism upregulated in patients compared to controls.

Conclusion

Using a combination of LC-MS and NMR methodologies we identified several altered mechanisms possibly related to AD pathology. EVs require additional optimization prior to their possible utilization as a biological material for AD-related metabolomics studies.

Cell-Secreted Vesicles: Novel Opportunities in Cancer Diagnosis, Monitoring and Treatment

Extracellular vesicles (EVs) are important mediators of intercellular communication playing a pivotal role in the regulation of physiological and pathological processes, including cancer. In particular, there is significant evidence suggesting that tumor-derived EVs exert an immunosuppressive activity during cancer progression, as well as stimulate tumor cell migration, angiogenesis, invasion and metastasis. The use of EVs as a liquid biopsy is currently a fast-growing area of research in medicine, with the potential to provide a step-change in the diagnosis and treatment of cancer, allowing the prediction of both therapy response and prognosis. EVs could be useful not only as biomarkers but also as drug delivery systems, and may represent a target for anticancer therapy. In this review, we attempted to summarize the current knowledge about the techniques used for the isolation of EVs and their roles in cancer biology, as liquid biopsy biomarkers and as therapeutic tools and targets.

Global analysis of a cancer model with drug resistance due to Lamarckian induction and microvesicle transfer

Development of resistance to chemotherapy in cancer patients strongly effects the outcome of the treatment. Due to chemotherapeutic agents, resistance can emerge by Darwinian evolution. Besides this, acquired drug resistance may arise via changes in gene expression. A recent discovery in cancer research uncovered a third possibility, indicating that this phenotype conversion can occur through the transfer of microvesicles from resistant to sensitive cells, a mechanism resembling the spread of an infectious agent. We present a model describing the evolution of sensitive and resistant tumour cells considering Darwinian selection, Lamarckian induction and microvesicle transfer. We identify three threshold parameters which determine the existence and stability of the three possible equilibria. Using a simple Dulac function, we give a complete description of the dynamics of the model depending on the three threshold parameters. We also establish an agent based model as a spatial version of the ODE model and compare the outputs of the two models. We find that although the ODE model does not provide spatial information about the structure of the tumour, it is capable to determine the outcome in terms of tumour size and distribution of cell types. We demonstrate the possible effects of increasing drug concentration, and characterize the possible bifurcation sequences. Our results show that the presence of microvesicle transfer cannot ruin a therapy that otherwise leads to extinction, however it may doom a partially successful therapy to failure.

Exploiting the metabolic energy demands of drug efflux pumps provides a strategy to overcome multidrug resistance in cancer

BACKGROUND

P-glycoprotein (P-gp) is a prevalent resistance mediator and it requires considerable cellular energy to ensure ATP dependent efflux of anticancer drugs. The glycolytic pathway generates the majority of catabolic energy in cancer cells; however, the high rates of P-gp activity places added strain on its inherently limited capacity to generate ATP. This is particularly relevant for compounds such as verapamil that are believed to trap P-gp in a futile transport process that requires continuing ATP consumption. Ultimately, this leads to cell death and the hypersensitivity of resistant cells to verapamil is termed collateral sensitivity.

RESULTS

We show that the addition of verapamil to resistant cells produces a prominent reduction in ATP levels that supports the idea of disrupted energy homeostasis. Even in the absence of verapamil, P-gp expressing cells display near maximal rates of glycolysis and oxidative phosphorylation, which prevents an adequate response to the demand for ATP to sustain transport activity. Moreover, the near perpetually maximal rate of oxidative phosphorylation in the presence of verapamil resulted in elevated levels of reactive oxygen species that affect cell survival and underscore collateral sensitivity.

CONCLUSIONS

Our results demonstrate that the strained metabolic profiles of P-gp expressing resistant cancer cells can be overwhelmed by additional ATP demands.

GENERAL SIGNIFICANCE

Consequently, collateral sensitising drugs may overcome the resistant phenotype by exploiting, rather than inhibiting, the energy demanding activity of pumps such as P-gp.

Visualizing Extracellular Vesicles and Their Function in 3D Tumor Microenvironment Models

Extracellular vesicles (EVs) are cell-derived nanostructures that mediate intercellular communication by delivering complex signals in normal tissues and cancer. The cellular coordination required for tumor development and maintenance is mediated, in part, through EV transport of molecular cargo to resident and distant cells. Most studies on EV-mediated signaling have been performed in two-dimensional (2D) monolayer cell cultures, largely because of their simplicity and high-throughput screening capacity. Three-dimensional (3D) cell cultures can be used to study cell-to-cell and cell-to-matrix interactions, enabling the study of EV-mediated cellular communication. 3D cultures may best model the role of EVs in formation of the tumor microenvironment (TME) and cancer cell-stromal interactions that sustain tumor growth. In this review, we discuss EV biology in 3D culture correlates of the TME. This includes EV communication between cell types of the TME, differences in EV biogenesis and signaling associated with differing scaffold choices and in scaffold-free 3D cultures and cultivation of the premetastatic niche. An understanding of EV biogenesis and signaling within a 3D TME will improve culture correlates of oncogenesis, enable molecular control of the TME and aid development of drug delivery tools based on EV-mediated signaling.

The effects and mechanisms of aloe-emodin on reversing adriamycin-induced resistance of MCF-7/ADR cells

Multidrug resistance (MDR) is one of the major obstacles for clinical effective chemotherapy. In this study, the effects and possible mechanisms of aloe-emodin (AE) were investigated on reversing the adriamycin (ADR)-induced resistance of MCF-7/ADR cells. AE could significantly reverse the ADR resistance in MCF-7/ADR cells. The combination of AE (20 μM) and ADR had no effect on the P-glycoprotein (P-gp) level, but notably promoted the accumulation of ADR in drug-resistant cells. The efflux function of P-gp required ATP, but AE reduced the intracellular ATP level. AE played a reversal role might through inhibiting the efflux function of P-gp. The research result of energy metabolism pathways indicated that combination of AE and ADR could inhibit glycolysis, tricarboxylic acid (TCA) cycle, glutamine metabolism, and related amino acid synthesis pathways. Moreover, we found AE not only reversed ADR-induced resistant but also induced autophagy as a defense mechanism. In addition, the combination of AE and ADR arrested G2/M cell cycle and induced apoptosis through DNA damage, ROS generation, caspase-3 activation. Our study indicated that AE could be a potential reversal agent to resensitize ADR resistant in tumor chemotherapy and inhibiting autophagy might be an effective strategy to further enhance the reversal activity of AE.

Chitinase 3-like-1 and fibronectin in the cargo of extracellular vesicles shed by human macrophages influence pancreatic cancer cellular response to gemcitabine

Tumour-associated macrophages have been implicated in pancreatic ductal adenocarcinoma (PDAC) therapy response and Extracellular vesicles (EVs) shed by macrophages might have a role in this process. Here, we demonstrated that large EVs released by anti-inflammatory human macrophages decreased PDAC cellular sensitivity to gemcitabine. Using proteomic analysis, chitinase 3-like-1 (CHI3L1) and fibronectin (FN1) were identified as two of the most abundant proteins in the cargo of macrophages-derived EVs. Overexpression of CHI3L1 and FN1, using recombinant human proteins, induced PDAC cellular resistance to gemcitabine through ERK (extracellular-signal-regulated kinase) activation. Inhibition of CHI3L1 and FN1 by pentoxifylline and pirfenidone, respectively, partially reverted gemcitabine resistance. In PDAC patient samples, CHI3L1 and FN1 were expressed in the stroma, associated with the high presence of macrophages. The Cancer Genome Atlas analysis revealed an association between CHI3L1 and FN1 gene expression, overall survival of PDAC patients, gemcitabine response, and macrophage infiltration. Altogether, our data identifies CHI3L1 and FN1 as potential targets for pharmacological inhibition in PDAC. Further pre-clinical in vivo work is warranted to study the possibility of repurposing pentoxifylline and pirfenidone as adjuvant therapies for PDAC treatment.

miRNAs mediated drug resistance in hematological malignancies

Despite improvements in the therapeutic approaches for hematological malignancies in the last decades, refractory disease still occurs, and cancer drug resistance still remains a major hurdle in the clinical management of these cancer patients. The investigation of this problem has been extensive and different mechanism and molecules have been associated with drug resistance. MicroRNAs (miRNAs) have been described as having an important action in the emergence of cancer, including hematological tumors, and as being major players in their progression, aggressiveness and response to treatments. Moreover, miRNAs have been strongly associated with cancer drug resistance and with the modulation of the sensitivity of cancer cells to a wide array of anticancer drugs. Furthermore, this role has also been reported for miRNAs packaged into extracellular vesicles (EVs-miRNAs), which in turn have been described as essential for the horizontal transfer of drug resistance to sensitive cells. Several studies have been suggesting the use of miRNAs as biomarkers for drug response and clinical outcome prediction, as well as promising therapeutic tools in hematological diseases. Indeed, the combination of miRNA-based therapeutic tools with conventional drugs contributes to overcome drug resistance. This review addresses the role of miRNAs in the pathogenesis of hematological malignances, namely multiple myeloma, leukemias and lymphomas, highlighting their important action (either in their cell-free circulating form or within circulating EVs) in drug resistance and their potential clinical applications.

The "Vesicular Intelligence" Strategy of Blood Cancers

Blood cancers are a heterogeneous group of disorders including leukemia, multiple myeloma, and lymphoma. They may derive from the clonal evolution of the hemopoietic stem cell compartment or from the transformation of progenitors with immune potential. Extracellular vesicles (EVs) are membrane-bound nanovesicles which are released by cells into body fluids with a role in intercellular communication in physiology and pathology, including cancer. EV cargos are enriched in nucleic acids, proteins, and lipids, and these molecules can be delivered to target cells to influence their biological properties and modify surrounding or distant targets. In this review, we will describe the “smart strategy” on how blood cancer-derived EVs modulate tumor cell development and maintenance. Moreover, we will also depict the function of microenvironment-derived EVs in blood cancers and discuss how the interplay between tumor and microenvironment affects blood cancer cell growth and spreading, immune response, angiogenesis, thrombogenicity, and drug resistance. The potential of EVs as non-invasive biomarkers will be also discussed. Lastly, we discuss the clinical application viewpoint of EVs in blood cancers. Overall, blood cancers apply a ‘vesicular intelligence’ strategy to spread signals over their microenvironment, promoting the development and/or maintenance of the malignant clone.

A distinct metabolic response characterizes sensitivity to EZH2 inhibition in multiple myeloma

Multiple myeloma (MM) is a heterogeneous haematological disease that remains clinically challenging. Increased activity of the epigenetic silencer EZH2 is a common feature in patients with poor prognosis. Previous findings have demonstrated that metabolic profiles can be sensitive markers for response to treatment in cancer. While EZH2 inhibition (EZH2i) has proven efficient in inducing cell death in a number of human MM cell lines, we hereby identified a subset of cell lines that despite a global loss of H3K27me3, remains viable after EZH2i. By coupling liquid chromatography-mass spectrometry with gene and miRNA expression profiling, we found that sensitivity to EZH2i correlated with distinct metabolic signatures resulting from a dysregulation of genes involved in methionine cycling. Specifically, EZH2i resulted in a miRNA-mediated downregulation of methionine cycling-associated genes in responsive cells. This induced metabolite accumulation and DNA damage, leading to G2 arrest and apoptosis. Altogether, we unveiled that sensitivity to EZH2i in human MM cell lines is associated with a specific metabolic and gene expression profile post-treatment.

Extracellular vesicles (EVs): What we know of the mesmerizing roles of these tiny vesicles in hematological malignancies?

Cancer is a complex disease in which a bidirectional collaboration between malignant cells and surrounding microenvironment creates an appropriate platform which ultimately facilitates the progression of the disease. The discovery of extracellular vesicles (EVs) was a turning point in the modern era of cancer biology, as their importance in human malignancies has set the stage to widen research interest in the field of cell-to-cell communication. The implication in short- and long-distance interaction via horizontally transfer of cellular components, ranging from non-coding RNAs to functional proteins, as well as stimulating target cells receptors by the means of ligands anchored on their membrane endows these "tiny vesicles with giant impacts" with incredible potential to re-educate normal tissues, and thus, to re-shape the surrounding niche. In this review, we highlight the pathogenic roles of EVs in human cancers, with an extensive focus on the recent advances in hematological malignancies.

Novel standardized method for extracellular flux analysis of oxidative and glycolytic metabolism in peripheral blood mononuclear cells

Analyzing metabolism of peripheral blood mononuclear cells (PBMCs) provides key opportunities to study the pathophysiology of several diseases, such as type 2 diabetes, obesity and cancer. Extracellular flux (XF) assays provide dynamic metabolic analysis of living cells that can capture ex vivo cellular metabolic responses to biological stressors. To obtain reliable data from PBMCs from individuals, novel methods are needed that allow for standardization and take into account the non-adherent and highly dynamic nature of PBMCs. We developed a novel method for extracellular flux analysis of PBMCs, where we combined brightfield imaging with metabolic flux analysis and data integration in R. Multiple buffy coat donors were used to demonstrate assay linearity with low levels of variation. Our method allowed for accurate and precise estimation of XF assay parameters by reducing the standard score and standard score interquartile range of PBMC basal oxygen consumption rate and glycolytic rate. We applied our method to freshly isolated PBMCs from sixteen healthy subjects and demonstrated that our method reduced the coefficient of variation in group mean basal oxygen consumption rate and basal glycolytic rate, thereby decreasing the variation between PBMC donors. Our novel brightfield image procedure is a robust, sensitive and practical normalization method to reliably measure, compare and extrapolate XF assay data using PBMCs, thereby increasing the relevance for PBMCs as marker tissue in future clinical and biological studies, and enabling the use of primary blood cells instead of immortalized cell lines for immunometabolic experiments.

Analysis of urinary exosomal metabolites identifies cardiovascular risk signatures with added value to urine analysis

BACKGROUND

Subclinical atherosclerosis may result in fatal cardiovascular (CV) events, but the underlying mechanisms and molecular players leading to disease are not entirely understood. Thus, novel approaches capable of identifying the factors involved in pathological progression and providing a better understanding of the subjacent mechanisms are needed. Extracellular vesicles (EVs) have been shown to have numerous biological functions, and their metabolome has recently generated interest as a source of novel biomarkers. The metabolic content of the exosomes has been so far unexplored in cardiovascular disease (CVD), and here, we developed an analytical strategy aimed at probing urinary exosomal metabolite content and its association to CV risk.

RESULTS

Direct analysis of the exosomes without metabolite extraction was evaluated by high-resolution magic angle spinning (¹H HR-MAS). Other two methodologies for the analysis of exosomal metabolites by ¹H NMR were set up, based on methanol or organic solvents sequential extraction. The three methods were compared in terms of the number of detected signals and signal to noise ratio (S/N). The methanol method was applied to identify altered metabolites in the urinary exosomes of subjects with programmed coronary artery by-pass grafting (CABG) versus a control group. Target mass spectrometry (MS) was also performed for differential analysis. The clinical performance of exosomal metabolites of interest in CVD was investigated, and the added value of the exosomes compared to urine analysis was evaluated. Based on S/N ratio, simplicity, reproducibility, and quality of the spectrum, the methanol method was chosen for the study in CVD. A cardiometabolic signature composed by 4-aminohippuric acid, N-1-methylnicotinamide, and citric acid was identified in urinary exosomes. Directly in urine, 4-aminohippuric acid and citric acid do not show variation between groups and changes in N-1-methylnicotinamide are less pronounced, proving the added value of exosomes.

CONCLUSIONS

We set up a novel methodology to analyze metabolic alterations in urinary exosomes and identified a cardiometabolic signature in these microvesicles. This study constitutes the first evidence of a role for the exosomal metabolism in CVD and demonstrates the possibility to evaluate the urinary exosomal metabolic content by NMR and MS.

Multifaceted activity of polyciclic MDR revertant agents in drug-resistant leukemic cells: Role of the spacer

A small library of derivatives carrying a polycyclic scaffold recently identified by us as a new privileged structure in medicinal chemistry was designed and synthesized, aiming at obtaining potent MDR reverting agents also endowed with antitumor properties. In particular, as a follow-up of our previous studies, attention was focused on the role of the spacer connecting the polycyclic core with a properly selected nitrogen-containing group. A relevant increase in reverting potency was observed, going from the previously employed but-2-ynyl- to a pent-3-ynylamino moiety, as in compounds 3d and 3e, while the introduction of a triazole ring proved to differently impact on the activity of the compounds. The docking results supported the data obtained by biological tests, showing, for the most active compounds, the ability to establish specific bonds with P-glycoprotein. Moreover, a multifaceted anticancer profile and dual in vitro activity was observed for all compounds, showing both revertant and antitumor effects on leukemic cells. In this respect, 3c emerged as a "triple-target" agent, endowed with a relevant reverting potency, a considerable antiproliferative activity and a collateral sensitivity profile.

PI3K/AKT pathway as a key link modulates the multidrug resistance of cancers

Multidrug resistance (MDR) is the dominant challenge in the failure of chemotherapy in cancers. Phosphatidylinositol 3-kinase (PI3K) is a lipid kinase that spreads intracellular signal cascades and regulates a variety of cellular processes. PI3Ks are considered significant causes of chemoresistance in cancer therapy. Protein kinase B (AKT) is also a significant downstream effecter of PI3K signaling, and it modulates several pathways, including inhibition of apoptosis, stimulation of cell growth, and modulation of cellular metabolism. This review highlights the aberrant activation of PI3K/AKT as a key link that modulates MDR. We summarize the regulation of numerous major targets correlated with the PI3K/AKT pathway, which is further related to MDR, including the expression of apoptosis-related protein, ABC transport and glycogen synthase kinase-3 beta (GSK-3β), synergism with nuclear factor kappa beta (NF-κB) and mammalian target of rapamycin (mTOR), and the regulation of glycolysis.

Mitochondrial spare respiratory capacity: Mechanisms, regulation, and significance in non-transformed and cancer cells

Mitochondrial metabolism must constantly adapt to stress conditions in order to maintain bioenergetic levels related to cellular functions. This absence of proper adaptation can be seen in a wide array of conditions, including cancer. Metabolic adaptation calls on mitochondrial function and draws on the mitochondrial reserve to meet increasing needs. Among mitochondrial respiratory parameters, the spare respiratory capacity (SRC) represents a particularly robust functional parameter to evaluate mitochondrial reserve. We provide an overview of potential SRC mechanisms and regulation with a focus on its particular significance in cancer cells.

Tumor microenvironment and epithelial mesenchymal transition as targets to overcome tumor multidrug resistance

It is well established that multifactorial drug resistance hinders successful cancer treatment. Tumor cell interactions with the tumor microenvironment (TME) are crucial in epithelial-mesenchymal transition (EMT) and multidrug resistance (MDR). TME-induced factors secreted by cancer cells and cancer-associated fibroblasts (CAFs) create an inflammatory microenvironment by recruiting immune cells. CD11b+/Gr-1+ myeloid-derived suppressor cells (MDSCs) and inflammatory tumor associated macrophages (TAMs) are main immune cell types which further enhance chronic inflammation. Chronic inflammation nurtures tumor-initiating/cancer stem-like cells (CSCs), induces both EMT and MDR leading to tumor relapses. Pro-thrombotic microenvironment created by inflammatory cytokines and chemokines from TAMs, MDSCs and CAFs is also involved in EMT and MDR. MDSCs are the most common mediators of immunosuppression and are also involved in resistance to targeted therapies, e.g. BRAF inhibitors and oncolytic viruses-based therapies. Expansion of both cancer and stroma cells causes hypoxia by hypoxia-inducible transcription factors (e.g. HIF-1α) resulting in drug resistance. TME factors induce the expression of transcriptional EMT factors, MDR and metabolic adaptation of cancer cells. Promoters of several ATP-binding cassette (ABC) transporter genes contain binding sites for canonical EMT transcription factors, e.g. ZEB, TWIST and SNAIL. Changes in glycolysis, oxidative phosphorylation and autophagy during EMT also promote MDR. Conclusively, EMT signaling simultaneously increases MDR. Owing to the multifactorial nature of MDR, targeting one mechanism seems to be non-sufficient to overcome resistance. Targeting inflammatory processes by immune modulatory compounds such as mTOR inhibitors, demethylating agents, low-dosed histone deacetylase inhibitors may decrease MDR. Targeting EMT and metabolic adaptation by small molecular inhibitors might also reverse MDR. In this review, we summarize evidence for TME components as causative factors of EMT and anticancer drug resistance.

The Role of Extracellular Vesicles in the Hallmarks of Cancer and Drug Resistance

Extracellular vesicles (EVs) mediate intercellular signaling and communication, allowing the intercellular exchange of proteins, lipids, and genetic material. Their recognized role in the maintenance of the physiological balance and homeostasis seems to be severely disturbed throughout the carcinogenesis process. Indeed, the modus operandi of cancer implies the highjack of the EV signaling network to support tumor progression in many (if not all) human tumor malignancies. We have reviewed the current evidence for the role of EVs in affecting cancer hallmark traits by: (i) promoting cell proliferation and escape from apoptosis, (ii) sustaining angiogenesis, (iii) contributing to cancer cell invasion and metastasis, (iv) reprogramming energy metabolism, (v) transferring mutations, and (vi) modulating the tumor microenvironment (TME) by evading immune response and promoting inflammation. Special emphasis was given to the role of EVs in the transfer of drug resistant traits and to the EV cargo responsible for this transfer, both between cancer cells or between the microenvironment and tumor cells. Finally, we reviewed evidence for the increased release of EVs by drug resistant cells. A timely and comprehensive understanding of how tumor EVs facilitate tumor initiation, progression, metastasis and drug resistance is instrumental for the development of innovative EV-based therapeutic approaches for cancer.

Optical Redox Imaging of Lonidamine Treatment Response of Melanoma Cells and Xenografts

PURPOSE

Fluorescence of co-enzyme reduced nicotinamide adenine dinucleotide (NADH) and oxidized flavoproteins (Fp) provides a sensitive measure of the mitochondrial redox state and cellular metabolism. By imaging NADH and Fp, we investigated the utility of optical redox imaging (ORI) to monitor cellular metabolism and detect early metabolic response to cancer drugs.

PROCEDURES

We performed ORI of human melanoma DB-1 cells in culture and DB-1 mouse xenografts to detect the redox response to lonidamine (LND) treatment.

RESULTS

For cultured cells, LND treatment for 45 min significantly lowered NADH levels with no significant change in Fp, resulting in a significant increase in the Fp redox ratio (Fp/(NADH+Fp)); 3-h prolonged treatment led to a decrease in NADH and an increase in Fp and a more oxidized redox state compared to control. Significant decrease in the mitochondrial redox capacity of LND-treated cells was observed for the first time. For xenografts, 45-min LND treatment resulted in a significant reduction of NADH content, no significant changes in Fp content, and a trend of increase in the Fp redox ratio. Intratumor redox heterogeneity was observed in both control and LND-treated groups.

CONCLUSION

Our results support the utility of ORI for evaluating cellular metabolism and monitoring early metabolic response to cancer drugs.

miRNa signature in small extracellular vesicles and their association with platinum resistance and cancer recurrence in ovarian cancer

Carboplatin, administered as a single drug or in combination with paclitaxel, is the standard chemotherapy treatment for patients with ovarian cancer (OVCA). Recent evidence suggests that miRNAs associated with small extracellular vesicles (sEVs) participate in the development of chemoresistance. We studied the effect of carboplatin in a heterogeneity population of OVCA cells and their derived sEVs to identify mechanisms associated with chemoresistance. sEVs were quantified using an engineered superparamagnetic material, gold-loaded ferric oxide nanotubes and a screen-printed electrode. miR-21-3p, miR-21-5p, and miR-891-5p are enriched in sEVs, and they contribute to carboplatin resistance in OVCA. Using a quantitative MS/MS, miR-21-5p activates glycolysis and increases the expression of ATP-binding cassette family and a detoxification enzyme. miR-21-3p and miR-891-5p increase the expression of proteins involved in DNA repair mechanisms. Interestingly, the levels of miR-891-5p within sEVs are significantly higher in patients at risk of ovarian cancer relapse. Identification of miRNAs in sEVs also provides the opportunity to track them in biological fluids to potentially determine patient response to chemotherapy.

Deep Sequencing Analysis Reveals Distinctive Non-Coding RNAs When Comparing Tumor Multidrug-Resistant Cells and Extracellular Vesicles with Drug-Sensitive Counterparts

Multidrug resistance (MDR) is one of the main limitations of cancer treatment. The overexpression of drug-efflux pumps, such as P-glycoprotein (P-gp), is a major cause of MDR. Importantly, different studies have shown that extracellular vesicles (EVs) participate in the communication between MDR cells and drug-sensitive counterparts, promoting dissemination of the MDR phenotype. In the present work, we aimed to identify RNA species present in MDR cells and in EVs released by those cells, which may be associated with the MDR phenotype. The RNA content from two pairs (leukemia and lung cancer) of MDR (P-gp overexpressing) cells and their drug-sensitive counterparts, as well as from their EVs, was analyzed by deep sequencing. Our results showed distinctive transcripts for MDR cells and their EVs, when compared with their drug-sensitive counterparts. Remarkably, two pseudogenes (a novel pseudogene and RNA 5.8S ribosomal pseudogene 2) were found to be increased in EVs released by MDR cells in both leukemia and lung cancer models. Moreover, six miRs (miR-204-5p, miR-139-5p, miR-29c-5p, miR-551b-3p, miR-29b-2-5p, and miR-204-3p) exhibited altered levels in lung cancer MDR cells and their EVs. This study provides insights into the contribution of EVs to MDR.

New uracil analogs as downregulators of ABC transporters in 5-fluorouracil-resistant human leukemia HL-60 cell line

Overexpression of ATP-binding cassette (ABC) transporters causing multidrug resistance (MDR) in cancer cells is one of the major obstacles in cancer chemotherapy. The 5-FU resistant subclone (HL-60/5FU) of the human HL-60 promyelocytic leukemia cell line was selected by the conventional method of continuous exposure of the cells to the drug up to 0.08 mmol/L concentration. HL-60/5FU cells exhibited six-fold enhanced resistance to 5-FU than HL-60 cells. RT-PCR and ELISA assay showed significant overexpression of MDR-related ABC transporters, ABCB1, ABCG2 but especially ABCC1 in the HL-60/5FU as compared with the parental cell line. Three novel synthetic 5-methylidenedihydrouracil analogs, U-236, U-332 and U-359, selected as highly cytotoxic for HL-60 cells in MTT test, showed similar cytotoxicity in the resistant cell line. When co-incubated with 5-FU, these analogs were found to down-regulate the expression of all three transporters. However, the most pronounced effect was caused by U-332 which almost completely abolished ABCC1 expression in the resistant HL-60/5FU cells. Additionally, U-332 inhibited the activity of ATPase, an enzyme which catalyzes hydrolysis of ATP, providing energy to efflux drugs from the cells through the cellular membranes. Taken together, the obtained data suggest that acquired 5-FU resistance in HL-60/5FU cells results from overexpression of ABCC1 and that targeting ABCC1 expression could be a potential approach to re-sensitize resistant leukemia cells to 5-FU. The synthetic uracil analog U-332, which can potently down-regulate ABC transporter expression and therefore disturb drug efflux, can be considered an efficient ABCC1 regulator in cancer cells.

Interplay of Darwinian Selection, Lamarckian Induction and Microvesicle Transfer on Drug Resistance in Cancer

Development of drug resistance in cancer has major implications for patients’ outcome. It is related to processes involved in the decrease of drug efficacy, which are strongly influenced by intratumor heterogeneity and changes in the microenvironment. Heterogeneity arises, to a large extent, from genetic mutations analogously to Darwinian evolution, when selection of tumor cells results from the adaptation to the microenvironment, but could also emerge as a consequence of epigenetic mutations driven by stochastic events. An important exogenous source of alterations is the action of chemotherapeutic agents, which not only affects the signalling pathways but also the interactions among cells. In this work we provide experimental evidence from in vitro assays and put forward a mathematical kinetic transport model to describe the dynamics displayed by a system of non-small-cell lung carcinoma cells (NCI-H460) which, depending on the effect of a chemotherapeutic agent (doxorubicin), exhibits a complex interplay between Darwinian selection, Lamarckian induction and the nonlocal transfer of extracellular microvesicles. The role played by all of these processes to multidrug resistance in cancer is elucidated and quantified.

TNF-α Modulates P-Glycoprotein Expression and Contributes to Cellular Proliferation via Extracellular Vesicles

P-glycoprotein (Pgp/ABCB1) overexpression is associated with multidrug resistance (MDR) phenotype and, consequently, failure in cancer chemotherapy. However, molecules involved in cell death deregulation may also support MDR. Tumor necrosis factor-alpha (TNF-α) is an important cytokine that may trigger either death or tumor growth. Here, we examined the role of cancer cells in self-maintenance and promotion of cellular malignancy through the transport of Pgp and TNF-α molecules by extracellular vesicles (membrane microparticles (MP)). By using a classical MDR model in vitro, we identified a positive correlation between endogenous TNF-α and Pgp, which possibly favored a non-cytotoxic effect of recombinant TNF-α (rTNF-α). We also found a positive feedback involving rTNF-α incubation and TNF-α regulation. On the other hand, rTNF-α induced a reduction in Pgp expression levels and contributed to a reduced Pgp efflux function. Our results also showed that parental and MDR cells spontaneously released MP containing endogenous TNF-α and Pgp. However, these MP were unable to transfer their content to non-cancer recipient cells. Nevertheless, MP released from parental and MDR cells elevated the proliferation index of non-tumor cells. Collectively, our results suggest that Pgp and endogenous TNF-α positively regulate cancer cell malignancy and contribute to changes in normal cell behavior through MP.

Systems biology approaches to investigating the roles of extracellular vesicles in human diseases

Extracellular vesicles (EVs) are membrane-enclosed structures secreted by cells. In the past decade, EVs have attracted substantial attention as carriers of complex intercellular information. They have been implicated in a wide variety of biological processes in health and disease. They are also considered to hold promise for future diagnostics and therapy. EVs are characterized by a previously underappreciated heterogeneity. The heterogeneity and molecular complexity of EVs necessitates high-throughput analytical platforms for detailed analysis. Recently, mass spectrometry, next-generation sequencing and bioinformatics tools have enabled detailed proteomic, transcriptomic, glycomic, lipidomic, metabolomic, and genomic analyses of EVs. Here, we provide an overview of systems biology experiments performed in the field of EVs. Furthermore, we provide examples of how in silico systems biology approaches can be used to identify correlations between genes involved in EV biogenesis and human diseases. Using a knowledge fusion system, we investigated whether certain groups of proteins implicated in the biogenesis/release of EVs were associated with diseases and phenotypes. Furthermore, we investigated whether these proteins were enriched in publicly available transcriptomic datasets using gene set enrichment analysis methods. We found associations between key EV biogenesis proteins and numerous diseases, which further emphasizes the key role of EVs in human health and disease.

Multiomic Profiling of Tyrosine Kinase Inhibitor-Resistant K562 Cells Suggests Metabolic Reprogramming To Promote Cell Survival

Resistance to chemotherapy can occur through a wide variety of mechanisms. Resistance to tyrosine kinase inhibitors (TKIs) often arises from kinase mutations-however, "off-target" resistance occurs but is poorly understood. Previously, we established cell line resistance models for three TKIs used in chronic myeloid leukemia treatment, and found that resistance was not attributed entirely to failure of kinase inhibition. Here, we performed global, integrated proteomic and transcriptomic profiling of these cell lines to describe mechanisms of resistance at the protein and gene expression level. We used whole transcriptome sequencing and SWATH-based data-independent acquisition mass spectrometry (DIA-MS), which does not require isotopic labels and provides quantitative measurements of proteins in a comprehensive, unbiased fashion. The proteomic and transcriptional data were correlated to generate an integrated understanding of the gene expression and protein alterations associated with TKI resistance. We defined mechanisms of resistance and two novel markers, CA1 and alpha-synuclein, that were common to all TKIs tested. Resistance to all of the TKIs was associated with oxidative stress responses, hypoxia signatures, and apparent metabolic reprogramming of the cells. Metabolite profiling and glucose-dependence experiments showed that resistant cells had routed their metabolism through glycolysis (particularly through the pentose phosphate pathway) and exhibited disruptions in mitochondrial metabolism. These experiments are the first to report a global, integrated proteomic, transcriptomic, and metabolic analysis of TKI resistance. These data suggest that although the mechanisms are complex, targeting metabolic pathways along with TKI treatment may overcome pan-TKI resistance.