Current status of methods to assess cancer drug resistance

Overcoming Chemotherapy Resistance in Metastatic Cancer: A Comprehensive Review

The management of metastatic cancer is complicated by chemotherapy resistance. This manuscript provides a comprehensive academic review of strategies to overcome chemotherapy resistance in metastatic cancer. The manuscript presents background information on chemotherapy resistance in metastatic cancer cells, highlighting its clinical significance and the current challenges associated with using chemotherapy to treat metastatic cancer. The manuscript delves into the molecular mechanisms underlying chemotherapy resistance in subsequent sections. It discusses the genetic alterations, mutations, and epigenetic modifications that contribute to the development of resistance. Additionally, the role of altered drug metabolism and efflux mechanisms, as well as the activation of survival pathways and evasion of cell death, are explored in detail. The strategies to overcome chemotherapy resistance are thoroughly examined, covering various approaches that have shown promise. These include combination therapy approaches, targeted therapies, immunotherapeutic strategies, and the repurposing of existing drugs. Each strategy is discussed in terms of its rationale and potential effectiveness. Strategies for early detection and monitoring of chemotherapy drug resistance, rational drug design vis-a-vis personalized medicine approaches, the role of predictive biomarkers in guiding treatment decisions, and the importance of lifestyle modifications and supportive therapies in improving treatment outcomes are discussed. Lastly, the manuscript outlines the clinical implications of the discussed strategies. It provides insights into ongoing clinical trials and emerging therapies that address chemotherapy resistance in metastatic cancer cells. The manuscript also explores the challenges and opportunities in translating laboratory findings into clinical practice and identifies potential future directions and novel therapeutic avenues. This comprehensive review provides a detailed analysis of strategies to overcome chemotherapy resistance in metastatic cancer. It emphasizes the importance of understanding the molecular mechanisms underlying resistance and presents a range of approaches for addressing this critical issue in treating metastatic cancer.

A Review: Genetic Mutations as a Key to Unlocking Drug Resistance in Cervical Cancer

Cervical cancer is the fourth most common cancer in women. Advanced stage and metastatic disease are often associated with poor clinical outcomes. This substantiates the absolute necessity for high-throughput diagnostic and treatment platforms that are patient and tumour specific. Cervical cancer treatment constitutes multimodal intervention. Systemic treatments such as chemotherapy and/or focal radiotherapy are typically applied as neoadjuvant and/or adjuvant strategies. Cisplatin constitutes an integral part of standard cervical cancer treatment approaches. However, despite initial patient response, de novo or delayed/acquired treatment resistance is often reported, and toxicity is of concern. Chemotherapy resistance is associated with major alterations in genomic, metabolomic, epigenetic and proteomic landscapes. This results in imbalanced homeostasis associated with pro-oncogenic and proliferative survival, anti-apoptotic benefits, and enhanced DNA damage repair processes. Although significant developments in cancer diagnoses and treatment have been made over the last two decades, drug resistance remains a major obstacle to overcome.

Empowering the Battle: Bioenhancers as Allies Against Cancer Drug Resistance

BACKGROUND

Drug resistance has been a great hindrance in the path of counteracting diseases like cancer and is driven by drugs misuse and overuse. In terms of cancer, resistance has been developed due to cellular changes, altered growth activation pathways, increased expression of efflux proteins, and changes in the local physiology of cancer (blood supply, tissue hydrodynamics, increased mutation rate/epigenetics, tumor cell heterogeneity). One of the approaches to address these challenges is the use of bioenhancers, which can overcome drug resistance, thereby improving bioavailability (BA).

CONCLUSION

Bioenhancers when combined with drugs can elicit pharmacological activity. They are generally combined with therapeutic agents at low doses, which increase the BA or therapeutic activity of active pharmaceutical ingredient (API). This review sheds light on the synthesis and classification of bio-enhancers. It also discusses different applications of bio-enhancers like piperine, ginger, quercetin, curcumin, etc. in the treatment of cancer. The review also presents some of the recent advancements in terms of nanocarriers for delivering API combined with bioenhancers.

A multiparametric fluorescent visualization approach for detecting drug resistance in living cancer cells

Drug resistance is a worldwide health care crisis which impedes disease treatment and increases financial burden, especially for its multifactorial nature and high complexity. Herein, we developed a multiparametric approach to visualize and detect drug resistance in living cancer cells, through the combination of DNA-templated covalent protein labeling strategy and fluorescent resonance energy transfer technique. Gefitinib resistance in non-small cell lung cancer caused by mesenchymal-epidermal transition factor (Met) overexpression and hyperactivation was investigated as a proof-of-concept. Unlike the traditional single-factor investigation, the proposed approach evaluated the contribution of three important parameters towards the resistance, including the changes of Met expression level, the homodimerization of Met with itself and the heterodimerization of Met with epidermal growth factor receptor (EGFR). A multiple regression model based on these three parameters was tentatively established for evaluation of the resistance level of laboratory-developed resistant cells and evaluation of the resistance level of patient-derived cells. Such an approach facilitates a quick identification of a drug resistance, to evaluate not only the resistance level but also the resistance mechanism.

Cancer Chemoresistance; Recent Challenges and Future Considerations

Cancer remains one of the serious health hazards and major causes of human mortality across the world. Despite the development of many typical antineoplastic drugs and introduction of novel targeted agents, chemoresistance constitutes a major challenge in the effective therapeutic management of cancer. Drug inactivation, efflux of anticancer agents, modification of target sites, enhanced repair of DNA damage, apoptosis failure and induction of epithelial-mesenchymal transition are the principal mechanisms of cancer chemoresistance. Moreover, epigenetics, cell signaling, tumor heterogeneity, stem cells, microRNAs, endoplasmic reticulum, tumor microenvironment and exosomes have also been implicated in the multifaceted phenomenon of anticancer drug resistance. The tendency of resistance is either intrinsically possessed or subsequently acquired by cancerous cells. From clinical oncology standpoint, therapeutic failure and tumor progression are the most probable consequences of cancer chemoresistance. Combination therapy can help to overcome the issue of drug resistance, and therefore, the development of such treatment regimens is recommended for counteracting the emergence and dissemination of cancer chemoresistance. This chapter outlines the current knowledge on underlying mechanisms, contributory biological factors and likely consequences of cancer chemoresistance. Besides, prognostic biomarkers, diagnostic methods and potential approaches to overcome the emergence of antineoplastic drug resistance have also been described.

Heparin and Heparin-Based Drug Delivery Systems: Pleiotropic Molecular Effects at Multiple Drug Resistance of Osteosarcoma and Immune Cells

One of the main problems of modern health care is the growing number of oncological diseases both in the elderly and young population. Inadequately effective chemotherapy, which remains the main method of cancer control, is largely associated with the emergence of multidrug resistance in tumor cells. The search for new solutions to overcome the resistance of malignant cells to pharmacological agents is being actively pursued. Another serious problem is immunosuppression caused both by the tumor cells themselves and by antitumor drugs. Of great interest in this context is heparin, a biomolecule belonging to the class of glycosaminoglycans and possessing a broad spectrum of biological activity, including immunomodulatory and antitumor properties. In the context of the rapid development of the new field of “osteoimmunology,” which focuses on the collaboration of bone and immune cells, heparin and delivery systems based on it may be of intriguing importance for the oncotherapy of malignant bone tumors. Osteosarcoma is a rare but highly aggressive, chemoresistant malignant tumor that affects young adults and is characterized by constant recurrence and metastasis. This review describes the direct and immune-mediated regulatory effects of heparin and drug delivery systems based on it on the molecular mechanisms of (multiple) drug resistance in (onco) pathological conditions of bone tissue, especially osteosarcoma.

Capillary microsampling-based single-cell metabolomics by mass spectrometry and its applications in medicine and drug discovery

Characterization of cellular metabolic states is a technical challenge in biomedicine. Cellular heterogeneity caused by inherent diversity in expression of metabolic enzymes or due to sensitivity of metabolic reactions to perturbations, necessitates single cell analysis of metabolism. Heterogeneity is typically seen in cancer and thus, single-cell metabolomics is expectedly useful in studying cancer progression, metastasis, and variations in cancer drug response. However, low sample volumes and analyte concentrations limit detection of critically important metabolites. Capillary microsampling-based mass spectrometry approaches are emerging as a promising solution for achieving single-cell omics. Herein, we focus on the recent advances in capillary microsampling-based mass spectrometry techniques for single-cell metabolomics. We discuss recent technical developments and applications to cancer medicine and drug discovery.

Advancements, Challenges, and Future Directions in Tackling Glioblastoma Resistance to Small Kinase Inhibitors

Simple Summary

Drug resistance is a major issue in brain tumor therapy. Despite novel promising therapeutic approaches, glioblastoma (GBM) remains refractory in showing beneficial responses to anticancer agents, as demonstrated by the failure in clinical trials of small kinase inhibitors. One of the reasons may lie in the development of different types of drug resistance mechanisms derived from the intrinsic heterogeneous nature of GBM. Obtaining insights into these mechanisms could improve the management of the clinical intervention and monitoring. Such insights could be achieved with the improvement of preclinical in vitro models for studying drug resistance.

Abstract

Despite clinical intervention, glioblastoma (GBM) remains the deadliest brain tumor in adults. Its incurability is partly related to the establishment of drug resistance, both to standard and novel treatments. In fact, even though small kinase inhibitors have changed the standard clinical practice for several solid cancers, in GBM, they did not fulfill this promise. Drug resistance is thought to arise from the heterogeneity of GBM, which leads the development of several different mechanisms. A better understanding of the evolution and characteristics of drug resistance is of utmost importance to improve the current clinical practice. Therefore, the development of clinically relevant preclinical in vitro models which allow careful dissection of these processes is crucial to gain insights that can be translated to improved therapeutic approaches. In this review, we first discuss the heterogeneity of GBM, which is reflected in the development of several resistance mechanisms. In particular, we address the potential role of drug resistance mechanisms in the failure of small kinase inhibitors in clinical trials. Finally, we discuss strategies to overcome therapy resistance, particularly focusing on the importance of developing in vitro models, and the possible approaches that could be applied to the clinic to manage drug resistance.

Osteosarcoma from the unknown to the use of exosomes as a versatile and dynamic therapeutic approach

The most common primary malignant tumor of bone in children is osteosarcoma (OS). Nowadays, the prognosis and the introduction of chemotherapy in OS have improved survival rates of patients. Nevertheless, the results are still unsatisfactory, especially, in patients with recurrent disease or metastatic. OS chemotherapy has two main challenges related to treatment toxicity and multiple drug resistance. In this way, nanotechnology has developed nanosystems capable of releasing the drug directly at the OS cells and decreasing the drug's toxicity. Exosomes (Exo), a cell-derived nano-sized and a phospholipid vehicle, have been recognized as important drug delivery systems in several cancers. They are involved in a variety of biological processes and are an important mediator of long-distance intercellular communication. Exo can reduce inflammation and show low toxicity in healthy cells. Furthermore, the incorporation of specific proteins or peptides on the Exo surface improves their targeting capability in several clinical applications. Due to their unique structure and relevant characteristics, Exo is a promising nanocarrier for OS treatment. This review intends to describe the properties that turn Exo into an efficient, as well as safe nanovesicle for drug delivery and treatment of OS.

Battling Chemoresistance in Cancer: Root Causes and Strategies to Uproot Them

With nearly 10 million deaths, cancer is the leading cause of mortality worldwide. Along with major key parameters that control cancer treatment management, such as diagnosis, resistance to the classical and new chemotherapeutic reagents continues to be a significant problem. Intrinsic or acquired chemoresistance leads to cancer recurrence in many cases that eventually causes failure in the successful treatment and death of cancer patients. Various determinants, including tumor heterogeneity and tumor microenvironment, could cause chemoresistance through a diverse range of mechanisms. In this review, we summarize the key determinants and the underlying mechanisms by which chemoresistance appears. We then describe which strategies have been implemented and studied to combat such a lethal phenomenon in the management of cancer treatment, with emphasis on the need to improve the early diagnosis of cancer complemented by combination therapy.

Hsa-miR-107 regulates chemosensitivity and inhibits tumor growth in hepatocellular carcinoma cells

Hepatocellular carcinoma is a common type of liver cancer. Resistance to chemotherapeutic agents is a major problem in cancer therapy. MicroRNAs have been reported in cancer development and tumor growth; however, the relationship between chemoresistance and hepatocellular carcinoma needs to be fully investigated. Here, we treated hepatocellular carcinoma cell line (HA22T) with a histone deacetylase inhibitor to establish hepatocellular carcinoma-resistant cells (HDACi-R) and investigated the molecular mechanisms of chemoresistance in HCC cells. Although histone deacetylase inhibitor could not enhance cell death in HDACi-R but upregulation of miR-107 decreased cell viability both in parental cells and resistance cells, decreased the expression of cofilin-1, enhanced ROS-induced cell apoptosis, and dose-dependently sensitized HDACi-R to HDACi. Further, miR-107 upregulation resulted in tumor cell disorganization in both HA22T and HDACi-R in a mice xenograft model. Our findings demonstrated that miR-107 downregulation leads to hepatocellular carcinoma cell resistance in HDACi via a cofilin-1-dependent molecular mechanism and ROS accumulation.

Penile Cancer-Derived Cells Molecularly Characterized as Models to Guide Targeted Therapies

Penile cancer (PeCa) is a common disease in poor and developing countries, showing high morbidity rates. Despite the recent progress in understanding the molecular events involved in PeCa, the lack of well-characterized in vitro models precludes new advances in anticancer drug development. Here we describe the establishment of five human primary penile cancer-derived cell cultures, including two epithelial and three cancer-associated fibroblast (CAF) cells. Using high-throughput genomic approaches, we found that the epithelial PeCa derived- cells recapitulate the molecular alterations of their primary tumors and present the same deregulated signaling pathways. The differentially expressed genes and proteins identified are components of key oncogenic pathways, including EGFR and PI3K/AKT/mTOR. We showed that epithelial PeCa derived cells presented a good response to cisplatin, a common therapeutic approach used in PeCa patients. The growth of a PeCa-derived cell overexpressing EGFR was inhibited by EGFR inhibitors (cetuximab, gefitinib, and erlotinib). We also identified CAF signature markers in three PeCa-derived cells with fibroblast-like morphology, indicating that those cells are suitable models for PeCa microenvironment studies. We thus demonstrate the utility of PeCa cell models to dissect mechanisms that promote penile carcinogenesis, which are useful models to evaluate therapeutic approaches for the disease.

Targeting Molecular Mechanisms Underlying Treatment Efficacy and Resistance in Osteosarcoma: A Review of Current and Future Strategies

Osteosarcoma is the most common primary malignant bone tumour in children and adolescents. Due to micrometastatic spread, radical surgery alone rarely results in cure. Introduction of combination chemotherapy in the 1970s, however, dramatically increased overall survival rates from 20% to approximately 70%. Unfortunately, large clinical trials aiming to intensify treatment in the past decades have failed to achieve higher cure rates. In this review, we revisit how the heterogenous nature of osteosarcoma as well as acquired and intrinsic resistance to chemotherapy can account for stagnation in therapy improvement. We summarise current osteosarcoma treatment strategies focusing on molecular determinants of treatment susceptibility and resistance. Understanding therapy susceptibility and resistance provides a basis for rational therapy betterment for both identifying patients that might be cured with less toxic interventions and targeting resistance mechanisms to sensitise resistant osteosarcoma to conventional therapies.

Impedance-based drug-resistance characterization of colon cancer cells through real-time cell culture monitoring

Interest in impedance-based cellular assays is rising due to their remarkable advantages, including label-free, low cost, non-invasive, non-destructive, quantitative and real-time monitoring. In order to test their potential in cancer treatment decision and early detection of chemoresistance, we devised a new custom-made impedance measuring system based on electric cell-substrate impedance sensing (ECIS), optimized for long term impedance measurements. This device was employed in a proof of concept cell culture impedance analysis for the characterization of chemo-resistant colon cancer cells. Doxorubicin-resistant HT-29 cells were used for this purpose and monitored for 140 h. Analysis of impedance-based curves reveal different trends from chemo-sensitive and chemo-resistant cells. An impedance-based cytoxicity assay with different concentrations of doxorubicin was also performed using ECIS. The obtained results confirm the feasibility of ECIS in the study of drug resistance and show promises for studies of time-dependent factors related to physiological and behavioral changes in cells during resistance acquisition. The methodology presented herein, allows the continuous monitoring of cells under normal culture conditions as well as upon drug exposure. The ECIS device used, sets the basis for high-throughput early detection of resistance to drugs, administered in the clinical practice to cancer patients, and for the screening of new drugs in vitro, on patient-derived cells.

Monitoring of drug resistance towards reducing the toxicity of pharmaceutical compounds: Past, present and future

Drug resistance is worldwide health care crisis which decrease drug efficacy and developing toxicities. Effective resistance detection techniques could alleviate treatment cost and mortality associated with this crisis. In this review, the conventional and modern analysis methods for monitoring of drug resistance are presented. Also, various types of emerging rapid and sensitive techniques including electrochemical, electrical, optical and nano-based methods for the screening of drug resistance were discussed. Applications of various methods for the sensitive and rapid detection of drug resistance are investigated. The review outlines existing key issues in the determination which must be overcome before any of these techniques becomes a feasible method for the rapid detection of drug resistance. In this review, the roles of nanomaterials on development of novel methods for the monitoring of drug resistance were presented. Also, limitations and challenges of conventional and modern methods were discussed.

Towards early monitoring of chemotherapy-induced drug resistance based on single cell metabolomics: Combining single-probe mass spectrometry with machine learning

Despite the presence of methods evaluating drug resistance during chemotherapies, techniques, which allow for monitoring the degree of drug resistance in early chemotherapeutic stage from single cells in their native microenvironment, are still absent. Herein, we report an analytical approach that combines single cell mass spectrometry (SCMS) based metabolomics with machine learning (ML) models to address the existing challenges. Metabolomic profiles of live cancer cells (HCT-116) with different levels (i.e., no, low, and high) of chemotherapy-induced drug resistance were measured using the Single-probe SCMS technique. A series of ML models, including random forest (RF), artificial neural network (ANN), and penalized logistic regression (LR), were constructed to predict the degrees of drug resistance of individual cells. A systematic comparison of performance was conducted among multiple models, and the method validation was carried out experimentally. Our results indicate that these ML models, especially the RF model constructed on the obtained SCMS datasets, can rapidly and accurately predict different degrees of drug resistance of live single cells. With such rapid and reliable assessment of drug resistance demonstrated at the single cell level, our method can be potentially employed to evaluate chemotherapeutic efficacy in the clinic.

A ketogenic diet combined with melatonin overcomes cisplatin and vincristine drug resistance in breast carcinoma syngraft

OBJECTIVES

Chemotherapy is one of the major treatments of cancer. However, the emergence of resistance to chemotherapeutic agents is still a major obstacle in the successful management of resistant tumors. Therefore, development of new mechanisms to overcome drug resistance is essential and may be further developed into effective therapies that can flip the switch from drug resistance to susceptibility. The aim of this study was to evaluate a combination consisting of a ketogenic diet and melatonin to determine whether it would inhibit cisplatin- and vincristine-resistant breast cancer.

METHODS

In the in vitro part of the study, drug-resistant cell lines were treated with melatonin and real-time polymerase chain reaction was used to measure levels of gene expression involved in apoptosis and resistance. On the protein level, the activity of caspase-3 and the level of vascular endothelin growth factor protein were determined. In the in vivo part, tumor-bearing mice received one of the following treatments: ketogenic diet, melatonin, combination of melatonin and ketogenic diet, vehicle, or chemotherapy.

RESULTS

Successful inhibition of resistant cell lines was achieved by melatonin. This inhibition was mediated by induction of apoptosis, inhibition of angiogenesis, and downregulation of resistance genes. A synergistic anticancer effect was observed between melatonin and the ketogenic diet against resistant breast tumors inoculated in mice with a cure rate of 70%.

CONCLUSIONS

The combination of melatonin and a ketogenic diet represents a promising option to overcome drug resistance in cancer chemotherapy. However, further testing on the protein level using flow cytometry is important to better understand the mechanisms of action.

Identification of pharmacodynamic biomarkers and common molecular mechanisms of response to genotoxic agents in cancer cell lines

PURPOSE

Genotoxic agents (GAs) including cisplatin, doxorubicin, gemcitabine, and topotecan are often used in cancer treatment. However, the response to GAs is variable among patients and predictive biomarkers are inadequate to select patients for treatment. Accurate and rapid pharmacodynamics measures of response can, thus, be useful for monitoring therapy and improve clinical outcomes.

METHODS

This study focuses on integrating a database of genome-wide response to treatment (The NCI Transcriptional Pharmacodynamics Workbench) with a database of baseline gene expression (GSE32474) for the NCI-60 cell lines to identify mechanisms of response and pharmacodynamic (PD) biomarkers.

RESULTS AND CONCLUSIONS

Our analysis suggests that GA-induced endoplasmic reticulum (ER) stress may signal for GA-induced cell death. Reducing the uptake of GA, activating DNA repair, and blocking ER-stress induction cooperate to prevent GA-induced cell death in the GA-resistant cells. ATF3, DDIT3, CARS, and PPP1R15A appear as possible candidate PD biomarkers for monitoring the progress of GA treatment. Further validation studies on the proposed intrinsic drug-resistant mechanism and candidate genes are needed using in vivo data from either patient-derived xenograft models or clinical chemotherapy trials.

Disruption of mitochondrial homeostasis with artemisinin unravels anti-angiogenesis effects via auto-paracrine mechanisms

Rationale: Tumor angiogenesis promotes tumor development, progression, growth, and metastasis. Metronomic chemotherapy involves the frequent administration of low-dose chemotherapeutic agents to block angiogenic activity and reduce side effects.

Methods: MDA-MB-231 cells were treated with various concentrations of artemisinin (ART) and vinorelbine (NVB) and the cytotoxic effects of ART/NVB were determined using the CCK-8 assay. Mitochondrial reactive oxygen species (ROS) levels, mitochondrial membrane potential (∆Ψm) and mass were assessed using MitoSOX, TMRE and MitoTracker green staining. Western blot analysis was used to quantify the expression of autophagy-related proteins. Herein, by using bioinformatics analysis and experimental verification, we identified CREB as a master in MDA-MB-231 cells.

Results: We found that artemisinin (ART), which exhibits anti-angiogenic and anti-cancer effects via mitochondrial regulation, synergized with vinorelbine (NVB) to inhibit MDA-MB-231 cell proliferation. ART and NVB cooperated to regulate mitochondrial biogenesis. CREB acted as a crucial regulator of PGC1α and VEGF, which played critical roles in NVB-dependent growth factor depletion. Moreover, CREB suppression significantly reversed mitochondrial dysfunction following ART/NVB co-treatment. In addition, combination treatment with ART and NVB significantly suppressed tumor growth in a nude mouse xenograft model, with downregulated CREB and PGC1α expression levels observed in tumor biopsies, in agreement with our in vitro and ex vivo data.

Conclusions: These findings support the hypothesis that ART affects cancer and endothelial cells by targeting the auto-paracrine effects of VEGF to suppress mitochondrial biogenesis, angiogenesis, and migration between cancer cells and endothelial cells.

Chemotherapy Resistance in Advanced Ovarian Cancer Patients

Ovarian cancer is the seventh most common gynaecologic malignancy seen in women. Majority of the patients with ovarian cancer are diagnosed at the advanced stage making prognosis poor. The standard management of advanced ovarian cancer includes tumour debulking surgery followed by chemotherapy. Various types of chemotherapeutic regimens have been used to treat advanced ovarian cancer, but the most promising and the currently used standard first-line treatment is carboplatin and paclitaxel. Despite improved clinical response and survival to this combination of chemotherapy, numerous patients either undergo relapse or succumb to the disease as a result of chemotherapy resistance. To understand this phenomenon at a cellular level, various macromolecules such as DNA, messenger RNA and proteins have been developed as biomarkers for chemotherapy response. This review comprehensively summarizes the problem that pertains to chemotherapy resistance in advanced ovarian cancer and provides a good overview of the various biomarkers that have been developed in this field.

Lidocine potentiates the cytotoxicity of 5-fluorouracil to choriocarcinoma cells by downregulating ABC transport proteins expression

Choriocarcinoma is a gestational trophoblastic cancer, which often occurs in the first 3 months of pregnancy. 5-Fluorouracil (5-Fu) is the widely used chemotherapeutic drug for choriocarcinoma but limited by drug resistance. Lidocaine, an aminamide-type anesthetic, shows potential anticancer and chemosensitization effects in recent years. Herein, we tested the possible chemosensitization activity of lidocaine on the cytotoxicity of 5-Fu in choriocarcinoma cells. Viabilities and apoptosis of choriocarcinoma JEG-3 and JAR cells after lidocaine and/or 5-Fu treatment were detected using Cell Counting Kit-8 assay, annexin V-FITC/PI (fluorescein isothiocyanate/propidium iodide) staining and Western blot analysis, respectively. Quantitative reverse transcription polymerase chain reaction was done to measure breast cancer resistance protein (ABCG2) messenger RNA level. Western blot analysis was carried out to detect ABCG2, P-glycoprotein (P-gp), MRP1, and MRP2 protein levels. pEX-ABCG2 was transfected to elevate ABCG2 level. Then, the influence of ABCG2 on lidocaine + 5-Fu-caused cell viability loss, apoptosis, and inactivation of PI3K/AKT pathway were analyzed. We found that lidocaine in low concentration had no significant cytotoxicity to JEG-3 and JAR cells, but stimulated cell apoptosis in high concentration. Moreover, lidocaine potentiated the cytotoxicity of 5-Fu to JEG-3 and JAR cells through decreasing viability and increasing apoptosis. Lidocaine treatment reduced the ABCG2, P-gp, MRP1, and MRP2 protein levels in cells. Overexpression of ABCG2 reversed the synergistic effects of lidocaine + 5-Fu on JEG-3 and JAR cell viability and apoptosis, as well as PI3K/AKT pathway. Our research verified that lidocaine potentiated the cytotoxicity of 5-Fu to choriocarcinoma cells by downregulating ATP-binding cassette (ABC) transport proteins expression.

Selected Aspects of Chemoresistance Mechanisms in Colorectal Carcinoma-A Focus on Epithelial-to-Mesenchymal Transition, Autophagy, and Apoptosis

Chemoresistance has been found in all malignant tumors including colorectal carcinoma (CRC). Nowadays chemoresistance is understood as a major reason for therapy failure, with consequent tumor growth and spreading leading ultimately to the patient's premature death. The chemotherapy-related resistance of malignant colonocytes may be manifested in diverse mechanisms that may exist both prior to the onset of the therapy or after it. The ultimate function of this chemoresistance is to ensure the survival of malignant cells through continuing adaptation within an organism, therefore, the nature and spectrum of cell-survival strategies in CRC represent a highly significant target of scientific inquiry. Among these survival strategies employed by CRC cells, three unique but significantly linked phenomena stand out-epithelial-to-mesenchymal transition (EMT), autophagy, and cell death. In this mini-review, current knowledge concerning all three mechanisms including their emergence, timeline, regulation, and mutual relationships will be presented and discussed.

Towards rapid prediction of drug-resistant cancer cell phenotypes: single cell mass spectrometry combined with machine learning

Combined single cell mass spectrometry and machine learning methods is demonstrated for the first time to achieve rapid and reliable prediction of the phenotype of unknown single cells based on their metabolomic profiles, with experimental validation. This approach can be potentially applied towards prediction of drug-resistant phenotypes prior to chemotherapy.

Distinctive behaviour of live biopsy-derived carcinoma cells unveiled using coherence-controlled holographic microscopy

Head and neck squamous cell carcinoma is one of the most aggressive tumours and is typically diagnosed too late. Late diagnosis requires an urgent decision on an effective therapy. An individualized test of chemosensitivity should quickly indicate the suitability of chemotherapy and radiotherapy. No ex vivo chemosensitivity assessment developed thus far has become a part of general clinical practice. Therefore, we attempted to explore the new technique of coherence-controlled holographic microscopy to investigate the motility and growth of live cells from a head and neck squamous cell carcinoma biopsy. We expected to reveal behavioural patterns characteristic for malignant cells that can be used to imrove future predictive evaluation of chemotherapy. We managed to cultivate primary SACR2 carcinoma cells from head and neck squamous cell carcinoma biopsy verified through histopathology. The cells grew as a cohesive sheet of suspected carcinoma origin, and western blots showed positivity for the tumour marker p63 confirming cancerous origin. Unlike the roundish colonies of the established FaDu carcinoma cell line, the SACR2 cells formed irregularly shaped colonies, eliciting the impression of the collective invasion of carcinoma cells. Time-lapse recordings of the cohesive sheet activity revealed the rapid migration and high plasticity of these epithelial-like cells. Individual cells frequently abandoned the swiftly migrating crowd by moving aside and crawling faster. The increasing mass of fast migrating epithelial-like cells before and after mitosis confirmed the continuation of the cell cycle. In immunofluorescence, analogously shaped cells expressed the p63 tumour marker, considered proof of their origin from a carcinoma. These behavioural traits indicate the feasible identification of carcinoma cells in culture according to the proposed concept of the carcinoma cell dynamic phenotype. If further developed, this approach could later serve in a new functional online analysis of reactions of carcinoma cells to therapy. Such efforts conform to current trends in precision medicine.

Therapeutic potential of CAR-T cell-derived exosomes: a cell-free modality for targeted cancer therapy

Chimeric antigen receptor (CAR)-based T-cell adoptive immunotherapy is a distinctively promising therapy for cancer. The engineering of CARs into T cells provides T cells with tumor-targeting capabilities and intensifies their cytotoxic activity through stimulated cell expansion and enhanced cytokine production. As a novel and potent therapeutic modality, there exists some uncontrollable processes which are the potential sources of adverse events. As an extension of this impactful modality, CAR-T cell-derived exosomes may substitute CAR-T cells to act as ultimate attackers, thereby overcoming some limitations. Exosomes retain most characteristics of parent cells and play an essential role in intercellular communications via transmitting their cargo to recipient cells. The application of CAR-T cell-derived exosomes will make this cell-based therapy more clinically controllable as it also provides a cell-free platform to diversify anticancer mediators, which responds effectively to the complexity and volatility of cancer. It is believed that the appropriate application of both cellular and exosomal platforms will make this effective treatment more practicable.

Electroneutral composite polymersomes self-assembled by amphiphilic polyphosphazenes for effective miR-200c in vivo delivery to inhibit drug resistant lung cancer

MiR-200c has been confirmed to display remarkable effects on proliferation inhibition and apoptosis induction of certain cancer cells, but the main challenge for its successful translation into the clinic remains its effective delivery to the action site in vivo. In this study, a novel composite polyphosphazene vesicle system composed of amphiphilic [NP(PEG)0.3(EAB)1.7]n (PEEP) and weakly cationic [NP(PEG)0.5(DPA)1.5]n (PEDP) was prepared via a very simple dialysis method. The loading of miR-200c was accomplished with high efficiency by taking advantage of the combination effect of physical encapsulation and electrostatic interaction between vectors and miR-200c. The resultant miR-200c-loaded PEEP-PEDP polymersome (Nano-ED-200c) displayed suitable particle size, electric neutrality, excellent Ribonuclease stability and hemocompatibility. We also evaluated its subsequent miR-200c function in paclitaxel resistance human lung cancer (A549/T) cells in culture and tumor xenografts in nude mice. The results showed that Nano-ED-200c could achieve a higher miR-200c level and the enhanced antitumor efficacy with 68% tumor inhibition ratio at a very low dose of 1.0 mg/kg than PEEP nanoparticle, PEDP nanoparticle, even than Lipo2000. All these evidences indicated that this miR-200c delivery via polyphosphazene vesicles could act as a potential new therapeutic option for paclitaxel resistant human lung cancer.

EGFR inhibition evokes innate drug resistance in lung cancer cells by preventing Akt activity and thus inactivating Ets-1 function

Nonsmall cell lung cancer (NSCLC) is the leading cause of cancer death worldwide. About 14% of NSCLCs harbor mutations in epidermal growth factor receptor (EGFR). Despite remarkable progress in treatment with tyrosine kinase inhibitors (TKIs), only 5% of patients achieve tumor reduction >90%. The limited primary responses are attributed partly to drug resistance inherent in the tumor cells before therapy begins. Recent reports showed that activation of receptor tyrosine kinases (RTKs) is an important determinant of this innate drug resistance. In contrast, we demonstrate that EGFR inhibition promotes innate drug resistance despite blockade of RTK activity in NSCLC cells. EGFR TKIs decrease both the mitogen-activated protein kinase (MAPK) and Akt protein kinase pathways for a short time, after which the Ras/MAPK pathway becomes reactivated. Akt inhibition selectively blocks the transcriptional activation of Ets-1, which inhibits its target gene, dual specificity phosphatase 6 (DUSP6), a negative regulator specific for ERK1/2. As a result, ERK1/2 is activated. Furthermore, elevated c-Src stimulates Ras GTP-loading and activates Raf and MEK kinases. These observations suggest that not only ERK1/2 but also Akt activity is essential to maintain Ets-1 in an active state. Therefore, despite high levels of ERK1/2, Ets-1 target genes including DUSP6 and cyclins D1, D3, and E2 remain suppressed by Akt inhibition. Reduction of DUSP6 in combination with elevated c-Src renews activation of the Ras/MAPK pathway, which enhances cell survival by accelerating Bim protein turnover. Thus, EGFR TKIs evoke innate drug resistance by preventing Akt activity and inactivating Ets-1 function in NSCLC cells.

MicroC(3): an ex vivo microfluidic cis-coculture assay to test chemosensitivity and resistance of patient multiple myeloma cells

Chemosensitivity and resistance assays (CSRAs) aim to direct therapies based upon ex vivo responses of patient tumor cells to chemotherapeutic drugs. However, successful CSRAs are yet to be developed. Here, we exposed primary CD138(+) multiple myeloma (MM) cells to bortezomib, a clinical proteasome inhibitor, in microfluidic-cis-coculture (MicroC(3)) incorporating the patient's own CD138(-) tumor-companion mononuclear cells to integrate some of the patients' own tumor microenvironment components in the CSRA design. Statistical clustering techniques segregated MicroC(3) responses into two groups which correctly identified all seventeen patients as either clinically responsive or non-responsive to bortezomib-containing therapies. In contrast, when the same patient MM samples were analyzed in the absence of the CD138(-) cells (monoculture), the tumor cell responses did not segregate into clinical response clusters. Thus, MicroC(3) identified bortezomib-therapy MM patient responses making it a viable CSRA candidate toward enabling personalized therapy.

The effect of intrinsic and acquired resistances on chemotherapy effectiveness

Although chemotherapy is one of the most common treatments for cancer, it can be only partially successful. Drug resistance is the main cause of the failure of chemotherapy. In this work, we present a mathematical model to study the impact of both intrinsic (preexisting) and acquired (induced by the drugs) resistances on chemotherapy effectiveness. Our simulations show that intrinsic resistance could be as dangerous as acquired resistance. In particular, our simulations suggest that tumors composed by even a small fraction of intrinsically resistant cells may lead to an unsuccessful therapy very quickly. Our results emphasize the importance of monitoring both intrinsic and acquired resistances during treatment in order to succeed and the importance of doing more experimental and genetic research in order to develop a pretreatment clinical test to avoid intrinsic resistance.

BMS-536924, an ATP-competitive IGF-1R/IR inhibitor, decreases viability and migration of temozolomide-resistant glioma cells in vitro and suppresses tumor growth in vivo

Glioma is the most common type of primary brain tumor. Despite the combination of surgery, chemotherapy, and radiotherapy, the median survival duration of patients with malignant glioma is still very short. Temozolomide (TMZ) is the primary and most promising therapeutic drug for glioma; however, it is easy to develop acquired resistance during treatment. Activation of receptor tyrosine kinases (RTKs) has been identified to be involved in the acquisition of resistance toward many anticancer drugs. So inhibition of RTKs might be a promising therapeutic strategy for overcoming or attenuating acquired drug resistance. Here, we have investigated the anticancer activities of BMS-536924, an ATP-competitive IGF-1R/IR inhibitor in glioma, especially TMZ-resistant glioma, both in vitro and in vivo. We found that BMS-536924 could effectively reduce viability of both TMZ-sensitive and -resistant glioma cells. BMS-536924 induced dramatic apoptosis in TMZ-resistant cells, and it also dramatically inhibited migration of TMZ-resistant cells. Importantly, BMS-536924 significantly suppressed glioma tumor growth in vivo. This is the first report on anticancer activity of BMS-536924 in glioma. BMS-536924 is a promising compound in the therapy of glioma, especially of TMZ-resistant glioma, which might shed new light on glioma therapy.

Nonclinical reproductive and developmental safety evaluation of the MAGE-A3 Cancer Immunotherapeutic, a therapeutic vaccine for cancer treatment

We assessed potential toxic effects of the MAGE-A3 Cancer Immunotherapeutic on female fertility and embryo-fetal, pre- and post-natal development in rats and on male fertility in rats and monkeys. Three groups of 48 female (Study 1) or 22 male (Study 2) CD rats received 5 or 3 injections of 100μL of saline, AS15 immunostimulant, or MAGE-A3 Cancer Immunotherapeutic (MAGE-A3 recombinant protein combined with AS15) at various timepoints pre- or post-mating. Male Cynomolgus monkeys (Study 3) received 8 injections of 500μL of saline (n=2) or the MAGE-A3 Cancer Immunotherapeutic (n=6) every 2 weeks. Rats were sacrificed on gestation day 20 or lactation day 25 (Study 1) or 9 weeks after first injection (Study 2) and monkeys, 3 days or 8 weeks after last injection. Injections were well tolerated. Female rat mating performance or fertility, pre- and post-natal survival, offspring development up to 25 days of age, and male mating performance (rats) or fertility parameters (rats and monkeys) were unaffected.

A short update on cancer chemoresistance

Chemotherapeutic interventions in cancer patients are limited by the appearance of chemoresistance. For instance, advanced lung and ovarian cancer patients relapse invariably after few cycles of platinum-based chemotherapy. Disseminated tumors are characterized by genetic instability/heterogeneity, thus containing or generating a repertoire of resistant subpopulations. At the cellular level, altered drug uptake, efflux, and metabolization, as well as modifications of drug targets, increased repair, and decreased cell death complement the limited perfusion and adverse hypoxic/acidic extracellular conditions at the tumor level in retaining cancer cell viability. Similarly, targeted therapy is rendered ineffective by mutations of the specific target protein within a few months or years of administration. Assessment of the expression profiles of resistant tumor cells revealed extensive changes in numerous pathways affecting hundreds of genes. Therefore, reversal of drug resistance will require individual profiles of drug resistance mediators and the combination of several specific drugs, targeting critical components to provide new therapeutic options.

The ability of hyaluronan fragments to reverse the resistance of C6 rat glioma cell line to temozolomide and carmustine

Aim of the study

Hyaluronan (HA) is an extracellular matrix (ECM) polymer that may contribute to the emergence of anti-cancer drug resistance. Attempts to reverse drug resistance using small hyaluronan oligomers (oHA) are being made. The initial reports suggest that the oHA fraction may effectively reverse anti-cancer drug resistance in glioma models. However, the reversal effects of oHA of defined molecular length on glioma cells have not been investigated yet. In this study, we examined HA fragments containing 2 disaccharide units (oHA-2), 5 disaccharide units (oHA-5), and 68 kDa hyaluronan polymer (HA-68k) as agents possibly reversing the resistance of a C6 rat glioma cell line to temozolomide (TMZ) and carmustine (BCNU).

Material and methods

A 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) viability assay was used to assess the cytotoxicity of TMZ and BCNU in the presence or absence of the hyaluronan fragments. By comparing viability of the cells, the reversal effects of HA fragments on TMZ and BCNU resistance in C6 glioma cells were assessed.

Results

We found statistically significant decreases in the viability of cells in the presence of TMZ+oHA-5 as compared to TMZ alone (51.2 ±4.5 vs. 74.2 ±5.8, p = 0.0031), BCNU+o-HA5 as compared to BCNU alone (49.3 ±4.4 vs. 65.6 ±5.7, p = 0.0119), and BCNU+HA-68k as compared to BCNU alone (55.2 ±2.3 vs. 65.6 ±5.7, p = 0.0496).

Conclusions

Conclusions: Hyaluronan oligomers of 5 disaccharide units (oHA-5) significantly reversed the resistance of C6 cells to TMZ and BCNU. The results are only preliminary and a more thorough follow-up investigation is required to assess their actual role.

Could a revision of the current guidelines for cancer drug use improve the quality of cancer treatment?

Clinical practice guidelines are indispensable for such a variable disease as malignant solid tumors, with the complex possibilities of drug treatment. The current guidelines may be criticized on several points, however. First, there is a lack of information on the outcome of treatment, such as the expected success and failure rates. Treating not only drug responders but also nonresponders, that is, patients with drug resistance, must result in failures. There is no mention of the possibility of excluding the drug nonresponders, identifiable by special laboratory tests and no consideration is given to the different side effects of the recommended drug regimens. Nor are there any instructions concerning tumor cases for which anticancer drug treatment is futile. In such cases, early palliative care may lead to significant improvements in both life quality and life expectancy. Not least, there is no transparency concerning the preparation of the guidelines: persons cannot be identified who could give a statement of conflicts of interest, and responsibility is assumed only by anonymous medical associations. A revision of the current guidelines could considerably improve cancer treatment.

Mechanisms and insights into drug resistance in cancer

Cancer drug resistance continues to be a major impediment in medical oncology. Clinically, resistance can arise prior to or as a result of cancer therapy. In this review, we discuss different mechanisms adapted by cancerous cells to resist treatment, including alteration in drug transport and metabolism, mutation and amplification of drug targets, as well as genetic rewiring which can lead to impaired apoptosis. Tumor heterogeneity may also contribute to resistance, where small subpopulations of cells may acquire or stochastically already possess some of the features enabling them to emerge under selective drug pressure. Making the problem even more challenging, some of these resistance pathways lead to multidrug resistance, generating an even more difficult clinical problem to overcome. We provide examples of these mechanisms and some insights into how understanding these processes can influence the next generation of cancer therapies.

Drug Resistance Mechanisms in Non-Small Cell Lung Carcinoma

Lung cancer is the most commonly diagnosed cancer in the world. “Driver” and “passenger” mutations identified in lung cancer indicate that genetics play a major role in the development of the disease, progression, metastasis and response to therapy. Survival rates for lung cancer treatment have remained stagnant at ~15% over the past 40 years in patients with disseminated disease despite advances in surgical techniques, radiotherapy and chemotherapy. Resistance to therapy; either intrinsic or acquired has been a major hindrance to treatment leading to great interest in studies seeking to understand and overcome resistance. Genetic information gained from molecular analyses has been critical in identifying druggable targets and tumor profiles that may be predictors of therapeutic response and mediators of resistance. Mutated or overexpressed epidermal growth factor receptor (EGFR) and translocations in the echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) genes (EML4-ALK) are examples of genetic aberrations resulting in targeted therapies for both localized and metastatic disease. Positive clinical responses have been noted in patients harboring these genetic mutations when treated with targeted therapies compared to patients lacking these mutations. Resistance is nonetheless a major factor contributing to the failure of targeted agents and standard cytotoxic agents. In this review, we examine molecular mechanisms that are potential drivers of resistance in non-small cell lung carcinoma, the most frequently diagnosed form of lung cancer. The mechanisms addressed include resistance to molecular targeted therapies as well as conventional chemotherapeutics through the activity of multidrug resistance proteins.

Mesenchymal stem cell-mediated cancer therapy: A dual-targeted strategy of personalized medicine

Cancer remains one of the leading causes of mortality and morbidity throughout the world. To a significant extent, current conventional cancer therapies are symptomatic and passive in nature. The major obstacle to the development of effective cancer therapy is believed to be the absence of sufficient specificity. Since the discovery of the tumor-oriented homing capacity of mesenchymal stem cells (MSCs), the application of specific anticancer gene-engineered MSCs has held great potential for cancer therapies. The dual-targeted strategy is based on MSCs' capacity of tumor-directed migration and incorporation and in situ expression of tumor-specific anticancer genes. With the aim of translating bench work into meaningful clinical applications, we describe the tumor tropism of MSCs and their use as therapeutic vehicles, the dual-targeted anticancer potential of engineered MSCs and a putative personalized strategy with anticancer gene-engineered MSCs.

Translational imaging endpoints to predict treatment response to novel targeted anticancer agents

Response Evaluation Criteria in Solid Tumors (RECIST) and World Health Organization (WHO) Criteria have been traditionally used for the evaluation of therapeutic response to chemotherapeutic treatment regimens. They determine anatomic criteria for patients response to anti-cancer therapy based on morphological measurements of each target lesion. While this assessment is justified for cytotoxic (chemotherapeutic) drugs, it is now recognized that morphological imaging protocols are poorly suited to the evaluation of the efficacy of novel signal transduction inhibitors (STIs) which exhibit cytostatic rather than cytotoxic properties. New imaging technologies are now designed to evaluate, in a functional manner, modifications in tumor metabolic activity, cellularity, and vascularization before a reduction in tumor volume can be detected. Introduction of physiological imaging end-points, derived from dynamic contrast-enhanced (DCE) imaging protocols--including magnetic resonance imaging (MRI), computed tomography (CT) and ultrasound (US)--allow for early assessment of disruption in tumor perfusion and permeability for targeted anti-angiogenic agents. Diffusion-weighted MRI (DWI) provides another physiological imaging end-point since tumor necrosis and cellularity are seen early in response to anti-angiogenic treatment. Changes in glucose and phospholipid turnover, based on metabolic MRI and positron emission tomography (PET), provide reliable markers for therapeutic response to novel receptor-targeting agents. Finally, novel molecular imaging techniques of protein and gene expression have been developed in animal models followed by a successful human application for gene therapy-based protocols.

Molecular targeted approaches for treatment of pancreatic cancer

Human pancreatic cancer remains a highly malignant disease with almost similar incidence and mortality despite extensive research. Many targeted therapies are under development. However, clinical investigation showed that single targeted therapies and most combined therapies were not able to improve the prognosis of this disease, even though some of these therapies had excellent anti-tumor effects in pre-clinical models. Cross-talk between cell proliferation signaling pathways may be an important phenomenon in pancreatic cancer, which may result in cancer cell survival even though some pathways are blocked by targeted therapy. Pancreatic cancer may possess different characteristics and targets in different stages of pathogenesis, maintenance and metastasis. Sensitivity to therapy may also vary for cancer cells at different stages. The unique pancreatic cancer structure with abundant stroma creates a tumor microenvironment with hypoxia and low blood perfusion rate, which prevents drug delivery to cancer cells. In this review, the most commonly investigated targeted therapies in pancreatic cancer treatment are discussed. However, how to combine these targeted therapies and/or combine them with chemotherapy to improve the survival rate of pancreatic cancer is still a challenge. Genomic and proteomic studies using pancreatic cancer samples obtained from either biopsy or surgery are recommended to individualize tumor characters and to perform drug sensitivity study in order to design a tailored therapy with minimal side effects. These studies may help to further investigate tumor pathogenesis, maintenance and metastasis to create cellular expression profiles at different stages. Integration of the information obtained needs to be performed from multiple levels and dimensions in order to develop a successful targeted therapy.