Drug Resistance In Cancer Mechanisms And Strategies

MULTI-DRUG RESISTANCE IN CANCER The book details the mechanisms underlying multi-drug cellular resistance and the targets of novel chemotherapeutic agents. Cancer is a major killer all over the world. Even with all the progress made, chemotherapy is still the mainstay of modern cancer treatment. The progression of the cellular defeat of numerous independent anticancer drugs in terms of their chemical structure is a major barrier to successful chemotherapy. Multi-drug resistance (MDR) is a term for the fact that most cancer patients exhibit this phenomenon. According to the numbers, drug resistance carries the blame for 90% of cancer patient deaths. Refractory cancer and tumor recurrence are common outcomes of prolonged chemotherapy. Because of the prevalence of drug-resistance mutations, the difficulty of treating tumors increases and the therapeutic efficacy of drugs decreases. Multi-Drug Resistance in Cancer: Mechanism and Treatment Strategies contains nine chapters that cover topics such as: studying the mechanics of resistance to drugs by autophagy; studies to delineate the role of efflux transporters; expression of drug transporters; resistance to targeted therapies in breast cancer; advances in metallodrug driven combination treatment for cancer; and use of natural agents for the overcoming of cancer drug resistance. The book aims to provide the latest data on the mechanisms of cellular resistance to anticancer agents currently used in clinical treatment. It provides a better understanding of the mechanisms of MDR and targets of novel chemotherapy agents which should guide future research concerning new effective strategies in cancer treatment. Audience This book is written for pharmaceutical and biomedical scientists and researchers at both the bench and in the clinic who are interested in the mechanisms and strategies for overcoming cancer’s multi-drug resistance.

A major objective of this book is to reveal unprecedented opportunities to understand and overcome drug resistance through the clinical assessment of rational therapeutic drug combinations and the use of predictive and prognostic biomarkers to enable patient stratification and tailor treatments. It offers to the readers an updated overview on the possible reasons of failure of new and promising therapeutic opportunities.

Drug resistance in cancer, whereby a portion of cancer cells evades chemotherapy, poses a profound and continuing challenge for the effective treatment of cancer. The principles underlying the biological mechanisms behind this phenomenon are clearly explained in this volume. A deeper understanding of drug resistance requires a quantitative appreciation of the dynamic forces that shape tumor growth, including spontaneous mutation and selection processes. The authors seek to explain and to simplify these complex mechanisms, and to place them in a clinical context. Clearly explained mathematical models are used to illustrate the biological principles and provide an insight into tumor development and the effectiveness and limitations of drug treatment. The volume is suitable for those with a nonmathematical background and aims to enhance the effectiveness of cancer therapy. This is the first book to provide such an integrated account, in a form accessible to both doctor and scientist.

Drug Resistance in Colorectal Cancer: Molecular Mechanisms and Therapeutic Strategies, Volume Eight, summarizes the molecular mechanisms of drug resistance in colorectal cancer, along with the most up-to-date therapeutic strategies available. The book discusses reasons why colorectal tumors become refractory during the progression of the disease, but also explains how drug resistance occurs during chemotherapy. In addition, users will find the current therapeutic strategies used by clinicians in their practice in treating colorectal cancer. The combination of conventional anticancer drugs with chemotherapy-sensitizing agents plays a pivotal role in improving the outcome of colorectal cancer patients, in particular those with drug-resistant cancer cells. From a clinical point-of-view, the content of this book provides clinicians with updated therapeutic strategies for a better choice of drugs for drug-resistant colorectal cancer patients. It will be a valuable source for cancer researchers, oncologists and several members of biomedical field who are dedicated to better treat patients with colorectal cancer. Presents a systemic summary of molecular mechanisms for a quick and in-depth understanding Updates current trends in the field with pioneering information on drug resistance Encompasses both basic and clinical approaches for a better understanding of unsolved problems from a holistic point-of-view

Basic scientific background Breast cancer is one of the most common cancer and the most frequent cause of cancer death among women worldwide. Currently, subtyping breast cancers into hormone receptor (HR) positive, human epidermal growth factor receptor-2 overexpressing (HER2+), and triple negative breast cancer (TNBC) is the basis of diagnosing and treating this disease. The main treatment strategies for breast cancer include surgery, endocrine therapy, molecular targeted therapy, chemotherapy, radiotherapy, immunotherapy and gene therapy. However, resistance of breast cancer cells to chemotherapeutic agents, molecular targeted therapies and immunotherapy may occur either intrinsically or de nova, and is often ultimately responsible for treatment failure. Therefore, drug resistance poses a major challenge to breast cancer treatment. Current developments: Drug resistance in breast cancer is a complex clinical condition originating from a wide range of molecular alterations. The development of endocrine therapy resistance is believed to be associated with many cellular changes, such as ESR1 gene mutations, bypassing estrogen signaling pathway and altered tamoxifen metabolism. Meanwhile, changes in immune response, alternation of drug-binding property and downstream pathways are involved in the mechanisms of drug resistance in HER2+ breast cancer. In addition, resistance to chemotherapeutic agents predominantly arises from increased drug efflux and cross resistance. Current studies suggest that treatment strategies and therapeutics have to be designed specifically to each patient in different clinical situations. The use of modern genomic, proteomic and functional analytical techniques has contributed to identify novel genes and signaling networks involved in breast cancer drug resistance. Moreover, the use of high-throughput techniques in combination with bioinformatics and systems biology approaches has aided the interrogation of clinical samples and allowed the identification of molecular signatures and genotypes that predict responses to certain drugs. Despite much progress has been made in the field of breast cancer drug resistance, such as combination therapy and drug-loaded nanoparticles, the complexity and variability of drug resistance mechanism still inevitably lead to the continuous occurrence of drug resistance. Therefore, with the increasing amounts of anti-breast cancer agents, there are now unprecedented opportunities to understand and overcome drug resistance through further research into mechanisms and corresponding strategies, which will help achieve lasting disease control and bring survival benefits to patients with advanced cancer. Papers of interest: The current Research Topic of Frontiers in Pharmacology focuses on publishing Original Research, Review articles and Case Reports focusing on (a) elucidating mechanisms of drug resistance in breast cancer, target mutations, tumor microenvironment, undiscovered genes and signaling pathways; (b) promising drug delivery systems that can enhance the sensitivity of anti- breast cancer agents to various tumors; (c) strategies that can improve patient care during bio-chemotherapeutic treatments; (d) small molecule compounds that are effective against drug-resistant breast tumors (e) biomarkers of chemotherapy resistance in breast cancer patients and (f) in vitro and in vivo models. Guidelines for article of submission: - Authors must stick to the set guidelines for ethical practices by the Frontiers journals. - The main content of the article must have certain innovation and research significance. - The authors should describe the construction method of drug-resistant cell lines when using them for experiments in the article.

It was estimated that in 2008, 1,437,180 patients would receive a new cancer diagnosisand 565,650individualswould die of cancer (Jemal et al. 2008).Since the vast majority of patients dying of cancer will have had anticancer therapy, both c- ventional chemotherapy and novel targeted therapy, it can be concluded that these patients are dying with drug resistant cancer. The term multidrug resistance is also apt – in that these patients die after having undergone multiple rounds of different and structurally unrelated cancer therapies. However, for some, the concept of m- tidrug resistance is a worn out idea, stemming from disappointment with the drug resistancereversalstrategiesthatwerecarriedoutinthe1990susingpumpinhibitors to block drug resistance mediated by P-glycoprotein, product of the MDR-1 gene. However, if one takes the larger de?nition – multidrug resistance as simultaneous resistance to multiple structurally unrelated anticancer therapies – its existence c- not be denied. The purpose of this book is to explore new concepts related to drug resistance in cancer, including resistance to the new molecularly targeted agents. Perhaps new terminology is needed for resistance that occurs following therapy with the targeted agents: Novel Targeted Agent Resistance (NTR). Alternatively, we can return to the original de?nition of multidrug resistance as simply the res- tance to multipleagents that occurs in the course of normalcancer progression.This resistance is likely to be mediated by many factors.

Over the last 50 years, drug development and clinical trials have resulted in successful complete responses in diseases such as childhood leukemia, testicular cancer and Hodgkin's disease. We are still, however, confronted with over 500,000 cancer-related deaths per year. Clearly, the phenomenon of drug resistance is largely responsible for these failures and continues to be an area of active investigation. Since the last volume in this series, we have learned that the energy-dependent drug efflux protein, p-glycoprotein, encoded by the MDR 1 gene, is a member of a family of structurally related transport polypeptides, thus allowing us to explore the relationship between structure and function. In addition to ongoing well designed clinical trials aimed at reversing MDR mediated drug resistance, the first gene therapy studies with the MDR 1 gene retrovirally transduced into human bone marrow cells are about to be initiated. Although MDR is currently the most understood mechanism of drug resistance, we are uncovering increasing knowledge of alternative molecular and biochemical mechanisms of drug resistance to antimetabolites, cisplatin and alkylating agents and developing new strategies for circumventing such resistance. It is clear that drug resistance is complex, and many mechanisms exist by which cancer cells may overcome the cytotoxicity of our known chemotherapeutic agents. As our understanding of each of these mechanisms expands, well designed models will be necessary to test laboratory hypotheses and determine their relationship to drug resistance in humans. It is this integration of basic science and clinical investigation that will both advance our scientific knowledge and result in the improvement of cancer therapy.