Friend or foe: the role of microRNA in chemotherapy resistance

Non-coding RNAs in leukemia drug resistance: new perspectives on molecular mechanisms and signaling pathways

Like almost all cancer types, timely diagnosis is needed for leukemias to be effectively cured. Drug efflux, attenuated drug uptake, altered drug metabolism, and epigenetic alterations are just several of the key mechanisms by which drug resistance develops. All of these mechanisms are orchestrated by up- and downregulators, in which non-coding RNAs (ncRNAs) do not encode specific proteins in most cases; albeit, some of them have been found to exhibit the potential for protein-coding. Notwithstanding, ncRNAs are chiefly known for their contribution to the regulation of physiological processes, as well as the pathological ones, such as cell proliferation, apoptosis, and immune responses. Specifically, in the case of leukemia chemo-resistance, ncRNAs have been recognized to be responsible for modulating the initiation and progression of drug resistance. Herein, we comprehensively reviewed the role of ncRNAs, specifically its effect on molecular mechanisms and signaling pathways, in the development of leukemia drug resistance.

Transfection of Unmodified MicroRNA Using Monolayer-Coated Au Nanoparticles as Gene-Delivery Vehicles

This article describes a monolayer-coated gold nanoparticle-based transfection system for the delivery of microRNA (miRNA) into human osteosarcoma (HOS) cells. Two distinct ammonium-terminated adsorbates were used in this study, which provided a platform for ionic bonding of the miRNA onto gold nanoparticles (AuNPs). The custom-designed monolayer-coated gold nanoparticles were characterized by dynamic light scattering, gel mobility shift assay, transmission electron microscopy, ultraviolet-visible spectrometry, zeta potential, and X-ray photoelectron spectroscopy. The miRNA-loaded gold nanoparticles were transfected, and the level of intracellular miRNA delivered and taken up by cells was measured by Taqman qPCR. The overall analysis indicated a successful delivery of miRNA into the HOS cells at an ∼11,000-fold increase compared to nontreated cells.

Ugonin P inhibits lung cancer motility by suppressing DPP-4 expression via promoting the synthesis of miR-130b-5p

Lung cancer is the leading cause of cancer-related death worldwide, and the survival rate of metastatic lung cancer is exceedingly low. Helminthostatchys Zeylanica (H. Zeylanica) is a Chinese herbal medicine renowned for its anti-inflammatory, immunomodulatory, and anti-cancer activities in various cellular and animal studies. The current study evaluated the effects of H. Zeylanica derivatives on lung cancer cells. We determined that dipeptidyl peptidase-4 (DPP-4) expression levels were higher in lung cancer tissues than in normal tissues. We also determined that DPP-4 expression levels were higher in the metastatic stage and strongly correlated with lung cancer survival rates. An H. Zeylanica derivative (ugonin P) was shown to inhibit DPP-4 mRNA and protein expression in two lung cancer cell lines in a dose-dependent manner. Ugonin P was shown to decrease migration and invasion activities in lung cancer cells while promoting the synthesis of miR-130b-5p, which was found to negatively regulate DPP-4 protein expression and cell motility in lung cancer. We determined that ugonin P suppresses the DPP-4-dependent migration and invasion of lung cancer cells by downregulating the RAF/MEK/ERK signalling pathway and enhancing the expression of miR-130b-5p. This study provides compelling evidence that ugonin P could be used to develop novel therapeutic agents for the treatment of lung cancer.

A comprehension of signaling pathways and drug resistance; an insight into the correlation between microRNAs and cancer

Despite the development of numerous therapies, cancer remains an incurable disease due to various factors, including drug resistance produced by cancer cells. MicroRNAs (miRNAs) regulate different target genes involved in biological and pathological processes, including cancer, through post-transcriptional mechanisms. The development of drug resistance in cancer treatment is a significant barrier because it decreases drug uptake, cellular transport, and changes in proteins involved in cell proliferation, survival, and apoptotic pathways. Numerous studies have found a connection between miRNAs and the development of drug resistance in cancer cells. This paper provides a broad overview of how miRNAs regulate signaling pathways and influence treatment resistance in different cancers.

Formulation and evaluation of a two-stage targeted liposome coated with hyaluronic acid for improving lung cancer chemotherapy and overcoming multidrug resistance

Multidrug resistance (MDR) has emerged as a prominent challenge contributing to the ineffectiveness of chemotherapy in treating non-small cell lung cancer (NSCLC) patients. Currently, mitochondria of cancer cells are identified as a promising target for overcoming MDR due to their crucial role in intrinsic apoptosis pathway and energy supply centers. Here, a two-stage targeted liposome (HA/TT LP/PTX) was successfully developed via a two-step process: PTX-loaded cationic liposome (TT LP/PTX) were formulated by lipid film hydration & ultrasound technique, followed by further coating with natural anionic polysaccharide hyaluronic acid (HA). TT, an amphipathic polymer conjugate of triphenylphosphine (TPP)-tocopheryl polyethylene glycol succinate (TPGS), was used to modify the liposomes for mitochondrial targeting. The average particle size, zeta potential and encapsulation efficiency (EE%) of HA/TT LP/PTX were found to be 153 nm, -30.3 mV and 92.1% based on the optimal prescription of HA/TT LP/PTX. Compared to cationic liposome, HA-coated liposomes showed improved stability and safety, including biological stability in serum, cytocompatibility, and lower hemolysis percentage. In drug-resistant A549/T cells, HA was shown to improve the cellular uptake of PTX through CD44 receptor-mediated endocytosis and subsequent degradation by hyaluronidase (HAase) in endosomes. Following this, the exposure of TT polymer facilitated the accumulation of PTX within the mitochondria. As a result, the function of mitochondria in A549/T cells was disturbed, leading to an increased ROS level, decreased ATP level, dissipated MMP, and increased G2/M phase arrest. This resulted in a higher apoptotic rate and stronger anticancer efficacy.

Next-generation nanomaterials: advancing ocular anti-inflammatory drug therapy

Ophthalmic inflammatory diseases, including conjunctivitis, keratitis, uveitis, scleritis, and related conditions, pose considerable challenges to effective management and treatment. This review article investigates the potential of advanced nanomaterials in revolutionizing ocular anti-inflammatory drug interventions. By conducting an exhaustive analysis of recent advancements and assessing the potential benefits and limitations, this review aims to identify promising avenues for future research and clinical applications. The review commences with a detailed exploration of various nanomaterial categories, such as liposomes, dendrimers, nanoparticles (NPs), and hydrogels, emphasizing their unique properties and capabilities for accurate drug delivery. Subsequently, we explore the etiology and pathophysiology of ophthalmic inflammatory disorders, highlighting the urgent necessity for innovative therapeutic strategies and examining recent preclinical and clinical investigations employing nanomaterial-based drug delivery systems. We discuss the advantages of these cutting-edge systems, such as biocompatibility, bioavailability, controlled release, and targeted delivery, alongside potential challenges, which encompass immunogenicity, toxicity, and regulatory hurdles. Furthermore, we emphasize the significance of interdisciplinary collaborations among material scientists, pharmacologists, and clinicians in expediting the translation of these breakthroughs from laboratory environments to clinical practice. In summary, this review accentuates the remarkable potential of advanced nanomaterials in redefining ocular anti-inflammatory drug therapy. We fervently support continued research and development in this rapidly evolving field to overcome existing barriers and improve patient outcomes for ophthalmic inflammatory disorders.

Breast cancer: miRNAs monitoring chemoresistance and systemic therapy

With a high mortality rate that accounts for millions of cancer-related deaths each year, breast cancer is the second most common malignancy in women. Chemotherapy has significant potential in the prevention and spreading of breast cancer; however, drug resistance often hinders therapy in breast cancer patients. The identification and the use of novel molecular biomarkers, which can predict response to chemotherapy, might lead to tailoring breast cancer treatment. In this context, accumulating research has reported microRNAs (miRNAs) as potential biomarkers for early cancer detection, and are conducive to designing a more specific treatment plan by helping analyze drug resistance and sensitivity in breast cancer treatment. In this review, miRNAs are discussed in two alternative ways-as tumor suppressors to be used in miRNA replacement therapy to reduce oncogenesis and as oncomirs to lessen the translation of the target miRNA. Different miRNAs like miR-638, miR-17, miR-20b, miR-342, miR-484, miR-21, miR-24, miR-27, miR-23 and miR-200 are involved in the regulation of chemoresistance through diverse genetic targets. For instance, tumor-suppressing miRNAs like miR-342, miR-16, miR-214, and miR-128 and tumor-promoting miRNAs like miR101 and miR-106-25 cluster regulate the cell cycle, apoptosis, epithelial to mesenchymal transition and other pathways to impart breast cancer drug resistance. Hence, in this review, we have discussed the significance of miRNA biomarkers that could assist in providing novel therapeutic targets to overcome potential chemotherapy resistance to systemic therapy and further facilitate the design of tailored therapy for enhanced efficacy against breast cancer.

A comprehensive survey into the role of exosomes in pancreatic cancer; from the origin of cancer to the progress and possibility of diagnosis and treatment

Pancreatic cancer is the fourth most common malignant tumor in the world, which has a high mortality rate due to high invasiveness, early metastases, lack of specific symptoms, and high invasiveness. Recent studies have shown that exosomes can be essential sources of biomarkers in pancreatic cancer. Over the past ten years, exosomes have been implicated in multiple trials to prevent the growth and metastasis of many cancers, including pancreatic cancer. Exosomes also play essential roles in immune evasion, invasion, metastasis, proliferation, apoptosis, drug resistance, and cancer stemness. Exosomes help cells communicate by carrying proteins and genetic material, such as non-coding RNAs, including mRNAs and microRNAs. This review examines the biological significance of exosomes in pancreatic cancer and their functions in tumor invasion, metastasis, treatment resistance, proliferation, stemness, and immune evasion. We also emphasize recent advances in our understanding of the main functions of exosomes in diagnosing and treating pancreatic cancer.

PRMT3-mediated arginine methylation of IGF2BP1 promotes oxaliplatin resistance in liver cancer

Although oxaliplatin-based chemotherapy has been effective in the treatment of hepatocellular carcinoma (HCC), primary or acquired resistance to oxaliplatin remains a major challenge in the clinic. Through functional screening using CRISPR/Cas9 activation library, transcriptomic profiling of clinical samples, and functional validation in vitro and in vivo, we identify PRMT3 as a key driver of oxaliplatin resistance. Mechanistically, PRMT3-mediated oxaliplatin-resistance is in part dependent on the methylation of IGF2BP1 at R452, which is critical for the function of IGF2BP1 in stabilizing the mRNA of HEG1, an effector of PRMT3-IGF2BP1 axis. Also, PRMT3 overexpression may serve as a biomarker for oxaliplatin resistance in HCC patients. Collectively, our study defines the PRTM3-IGF2BP1-HEG1 axis as important regulators and therapeutic targets in oxaliplatin-resistance and suggests the potential to use PRMT3 expression level in pretreatment biopsy as a biomarker for oxaliplatin-resistance in HCC patients.

Exosomes: A potential tool for immunotherapy of ovarian cancer

Ovarian cancer is a malignant tumor of the female reproductive system, with a very poor prognosis and high mortality rates. Chemotherapy and radiotherapy are the most common treatments for ovarian cancer, with unsatisfactory results. Exosomes are a subpopulation of extracellular vesicles, which have a diameter of approximately 30-100 nm and are secreted by many different types of cells in various body fluids. Exosomes are highly stable and are effective carriers of immunotherapeutic drugs. Recent studies have shown that exosomes are involved in various cellular responses in the tumor microenvironment, influencing the development and therapeutic efficacy of ovarian cancer, and exhibiting dual roles in inhibiting and promoting tumor development. Exosomes also contain a variety of genes related to ovarian cancer immunotherapy that could be potential biomarkers for ovarian cancer diagnosis and prognosis. Undoubtedly, exosomes have great therapeutic potential in the field of ovarian cancer immunotherapy. However, translation of this idea to the clinic has not occurred. Therefore, it is important to understand how exosomes could be used in ovarian cancer immunotherapy to regulate tumor progression. In this review, we summarize the biomarkers of exosomes in different body fluids related to immunotherapy in ovarian cancer and the potential mechanisms by which exosomes influence immunotherapeutic response. We also discuss the prospects for clinical application of exosome-based immunotherapy in ovarian cancer.

Gut Microbiota-MicroRNA Interactions in Intestinal Homeostasis and Cancer Development

Pre-clinical models and clinical studies highlight the significant impact of the host-microbiota relationship on cancer development and treatment, supporting the emerging trend for a microbiota-based approach in clinical oncology. Importantly, the presence of polymorphic microbes is considered one of the hallmarks of cancer. The epigenetic regulation of gene expression by microRNAs affects crucial biological processes, including proliferation, differentiation, metabolism, and cell death. Recent evidence has documented the existence of bidirectional gut microbiota-microRNA interactions that play a critical role in intestinal homeostasis. Importantly, alterations in microRNA-modulated gene expression are known to be associated with inflammatory responses and dysbiosis in gastrointestinal disorders. In this review, we summarize the current findings about miRNA expression in the intestine and focus on specific gut microbiota-miRNA interactions linked to intestinal homeostasis, the immune system, and cancer development. We discuss the potential clinical utility of fecal miRNA profiling as a diagnostic and prognostic tool in colorectal cancer, and demonstrate how the emerging trend of gut microbiota modulation, together with the use of personalized microRNA therapeutics, might bring improvements in outcomes for patients with gastrointestinal cancer in the era of precision medicine.

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.

Diagnostic and prognostic potential clustered miRNAs in bladder cancer

At specific genomic loci, miRNAs are in clusters and their association with copy number variations (CNVs) may exhibit abnormal expression in several cancers. Hence, the current study aims to understand the expression of miRNA clusters residing within CNVs and the regulation of their target genes in bladder cancer. To achieve this, we used extensive bioinformatics resources and performed an integrated analysis of recurrent CNVs, clustered miRNA expression, gene expression, and drug–gene interaction datasets. The study identified nine upregulated miRNA clusters that are residing on CNV gain regions and three miRNA clusters (hsa-mir-200c/mir-141, hsa-mir-216a/mir-217, and hsa-mir-15b/mir-16-2) are correlated with patient survival. These clustered miRNAs targeted 89 genes that were downregulated in bladder cancer. Moreover, network and gene enrichment analysis displayed 10 hub genes (CCND2, ETS1, FGF2, FN1, JAK2, JUN, KDR, NOTCH1, PTEN, and ZEB1) which have significant potential for diagnosis and prognosis of bladder cancer patients. Interestingly, hsa-mir-200c/mir-141 and hsa-mir-15b/mir-16-2 cluster candidates showed significant differences in their expression in stage-specific manner during cancer progression. Downregulation of NOTCH1 by hsa-mir-200c/mir-141 may also sensitize tumors to methotrexate thus suggesting potential chemotherapeutic options for bladder cancer subjects. To overcome some computational challenges and reduce the complexity in multistep big data analysis, we developed an automated pipeline called CmiRClustFinder v1.0 (https://github.com/msls-bioinfo/CmiRClustFinder_v1.0), which can perform integrated data analysis of 35 TCGA cancer types.

Novel application of rhein and its prodrug diacerein for reversing cancer-related multidrug resistance through the dual inhibition of P-glycoprotein efflux and STAT3-mediated P-glycoprotein expression

Multidrug resistance (MDR) is a multifactorial issue in cancer treatment. Drug efflux transporters, particularly P-glycoprotein (P-gp), are major contributors to such resistance. In the present study, we evaluated the P-gp-inhibiting and MDR-reversing effects of two compounds, namely rhein, an anthraquinone, and diacerein, the acetylated prodrug of rhein. ABCB1/Flp-In-293 was used as a model for investigating the related molecular mechanisms, and the multi-drug-resistant cancer cell line KB/VIN was used as a platform for evaluating the reversal of MDR0. The results indicated that at a concentration of 2.5 μM, both diacerein and rhein significantly inhibited P-gp efflux function. They also downregulated P-gp expression by interacting with the signal transducer and activator of transcription 3. Further investigation of the inhibitory mechanism of these compounds revealed that both stimulated P-gp ATPase activity dose dependently and engaged in the noncompetitive inhibition of rhodamine 123 efflux. Furthermore, rhein was revealed to be a potent reverser of MDR in cancer, and the combination of 30 μM rhein and 1000 nM vincristine exerted a strong synergistic effect, achieving a high combination index (CI) of 0.092. Diacerein demonstrated potential applications as a selective cytotoxic agent against multi-drug-resistant cancer cells at a concentration of > 18.92 μM and as a mild MDR reverser at doses of < 10 μM. In conclusion, diacerein and rhein are potential candidates for P-gp inhibition and MDR reversal in cancer cells.

Research Progress and Prospects of Autophagy in the Mechanism of Multidrug Resistance in Tumors

Although the treatment of cancer has made great strides in clinical practice, its high morbidity and fatality rates remain a major threat to human health. Multidrug resistance (MDR) often appears in the process of tumor treatment, leading to tumor refractory and aggravating the risk of tumor recurrence. Therefore, antitumor MDR plays a key role in tumor chemotherapy. Autophagy is an important process for the turnover of intracellular materials, which is commonly seen in the treatment of sensitive and multidrug-resistant tumors, and it can play different roles in various types of MDR tumor cells and tissues. Autophagy plays a dual regulatory role in MDR tumors. On the one hand, autophagy can promote the formation of MDR in tumor cells, weaken the killing effect of chemotherapy drugs on tumor cells, and play a protective role in tumor survival. On the other hand, autophagy production in the cellular environment can kill MDR tumor cells, reverse tumor resistance and enhance the efficiency of chemotherapy drugs. Therefore, the regulation of autophagy to overcome MDR has become increasingly significant in tumor chemotherapy. In this article, we discussed and summarized the research progress of autophagy in MDR tumors, mainly involving the different characteristics of autophagy in MDR cancer cells.

Effects of Chemotherapy for Metastatic Colorectal Cancer on the TGF-β Signaling and Related miRNAs hsa-miR-17-5p, hsa-miR-21-5p and hsa-miR-93-5p

Metastatic colorectal cancer (mCRC) patients are treated with standard chemotherapeutic drugs in the form of FOLFOX and FOLFIRI regimens. There are no reliable markers that could predict response to chemotherapy for mCRC. TGF-β signaling which interacts with microRNA (miRNA) network has important roles in tumor progression and chemotherapy resistance, thus the interplay between TGF-β signaling and miRNAs could be crucial for treatment response. The aim of this study was to analyze the effect of chemotherapy for mCRC on TGF-β signaling and related miRNAs. Hsa-miR-17-5p, hsa-miR-21-5p and hsa-miR-93-5p were selected out of 316 miRNAs with multiple targets within the TGF-β signaling by in silico analysis. SW620 cells were treated with chemotherapeutic drugs for mCRC for 1, 3 and 6 days and expression of selected miRNAs, PAI-1, CDH1 and VIM was measured. Expression of TGF-β signaling-related hsa-miR-17-5p, hsa-miR-21-5p and hsa-miR-93-5p was time-dependently altered in SW620 cells treated with chemotherapeutics for mCRC. The expression of hsa-miR-93-5p remained downregulated after 6 days under combined treatments FOX and FIRI as well as the hsa-miR-17-5p expression under FIRI. Chemotherapy regimens for mCRC increased expression of a major TGF-β signaling target gene PAI-1, independently of the selected miRNAs expression. These treatments also increased the expression of epithelial-mesenchymal transition (EMT) markers CDH1 and VIM on day 3 resulting in decrease of mesenchymal-like characteristics. However, their expression returned close to basal level on day 6. In conclusion, after initial response to chemotherapeutic drugs SW620 cells start to return close to the basal mesenchymal state while the long-term downregulated expression pattern of hsa-miR-93-5p and hsa-miR-17-5p makes them candidates worth testing as biomarkers for monitoring combined chemotherapeutic treatments therapy response in mCRC patients.

Combination therapy with miR-34a and doxorubicin synergistically induced apoptosis in T-cell acute lymphoblastic leukemia cell line

MicroRNAs are identified to take actively part in the development of different cancers. Reduced expression of tumor suppressor miRNAs leads to cancer cell development, so restoring the expression of these miRNAs can be an appropriate treatment option for cancer. Due to the heterogeneity of cancer cells, single-drug therapy often results in drug resistance. Therefore, the combination of chemotherapy with miRNA can be a powerful strategy for cancer treatment. In the current investigation, miR-34a mimic, and negative control were purchased and transfected using jetPEI reagents. Then the synergic effects of miR-34a in combination with doxorubicin were investigated on cell death of acute T-cell lymphoblastic leukemia Jurkat cell line, as well as the expression of some genes including Caspase-3, Bcl-2, and p53 which are involved in apoptosis. Our outcomes showed that this combination remarkably reduced the expression of the Bcl-2 gene, the target gene of miR-34a. According to the results of the MTT assay, the survival rate was significantly decreased compared to the untreated cells. Results of the flow cytometry assay and DAPI staining demonstrated an increased apoptosis rate of Jurkat cells in combination therapy. Moreover, cell cycle arrest was observed at the G2/M phase in cells that were treated with miR-34a/doxorubicin. Most importantly, we showed that the transfection of the Jurkat cells with miR-34a increased the sensitivity of these cells to doxorubicin. Furthermore, the combination of miR-34a and doxorubicin drug effectively increased apoptosis of treated cells. Therefore, this method can be used as an impressive treatment for T-ALL.

Ferroptosis: At the Crossroad of Gemcitabine Resistance and Tumorigenesis in Pancreatic Cancer

The overall five-year survival rate of pancreatic cancer has hardly changed in the past few decades (less than 10%) because of resistance to all known therapies, including chemotherapeutic drugs. In the past few decades, gemcitabine has been at the forefront of treatment for pancreatic ductal adenocarcinoma, but more strategies to combat drug resistance need to be explored. One promising possibility is ferroptosis, a form of a nonapoptotic cell death that depends on intracellular iron and occurs through the accumulation of lipid reactive oxygen species, which are significant in drug resistance. In this article, we reviewed gemcitabine-resistance mechanisms; assessed the relationship among ferroptosis, tumorigenesis and gemcitabine resistance, and explored a new treatment method for pancreatic cancer.

MicroRNA Expression Profiles and Breast Cancer Chemotherapy

Breast cancer is the most common malignancy diagnosed in women. Traditionally, radical surgical resection was the cornerstone of breast cancer management, with limited exceptions. In recent times, our enhanced appreciation of the biomolecular characteristics of breast cancer has transformed the treatment paradigm to include prescription of chemotherapeutical agents, radiotherapies, targeted therapies, as well as more refined surgical approaches. While treatments with such modalities have enhanced clinico-oncological outcomes for breast cancer patients, the efforts of oncological and translational research have concentrated on the identification of novel biomarkers which may successfully inform prognosis and response to therapies, improve current therapeutic strategies, and enhance prognostication. Mi(cro)RNAs are small, non-coding molecules which are known to play regulatory roles in governing gene expression and cellular activity. Measurement of miRNA expression profiles have been illustrated to inform the response to therapies, such as conventional chemotherapy, and are currently undergoing assessment as means of enhancing treatment strategies with these cytotoxic agents. Herein, this review outlines how chemotherapy prescription has revolutionised breast cancer treatment and illustrates the novel role of miRNAs as biomarkers capable of enhancing current therapeutic strategies using chemotherapy in patients being treated with curative intent for breast cancer.

EVs delivery of miR-1915-3p improves the chemotherapeutic efficacy of oxaliplatin in colorectal cancer

PURPOSE

Oxaliplatin is a crucial component of the combinatorial chemotherapeutic standard of care for advanced colorectal cancer (CRC). Unfortunately, a serious barrier to effective oxaliplatin treatment is drug resistance due to epithelial-mesenchymal transitioning (EMT). Interestingly, stable oxaliplatin-resistant CRC cell lines show differential expression of miR-1915-3p; thus, this microRNA may represent a potential modifier of oxaliplatin resistance in CRC cells.

METHODS

miR-1915-3p was over-expressed in oxaliplatin-resistant CRC cells and a non-tumorigenic intestinal cell line (FHC) via lentiviral transduction. Extracellular vesicles (EVs) were purified from transduced FHC cells and co-incubated with CRC cells. Expression levels of miR-1915-3p and other RNA species were assessed by RT-qPCR, while protein expression levels were assessed by Western blotting. The effects of miR-1915-3p on CRC viability were evaluated by proliferation, apoptosis assays, and Transwell assays. Effects of miR-1915-3p over-expression on in vivo oxaliplatin sensitivity was tested via murine xenograft models.

RESULTS

miRNA-1915-3p decreased EMT marker expression in oxaliplatin-resistant CRC cell lines and in vivo. FHC cells were able to produce and secrete miR-1915-3p-containing EVs, which we employed to mediate miR-1915-3p delivery to oxaliplatin-resistant CRC cells and increase their oxaliplatin sensitivity in vivo and in vitro. Mechanistically, miR-1915-3p overexpression downregulated the EMT-promoting oncogenes 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) and ubiquitin carboxyl-terminal hydrolase 2 (USP2) as well as upregulated E-cadherin (a cell adhesion mediator). miR-1915-3p's effects on chemosensitivity and EMT were mediated by its regulation of PFKFB3 and USP2.

CONCLUSION

Exosomal delivery of miR-1915-3p can improve the chemotherapeutic efficacy of oxaliplatin in CRC cells by suppressing the EMT-promoting oncogenes PFKFB3 and USP2.

α-naphthoflavone-derived cytochrome P450 (CYP)1B1 degraders specific for sensitizing CYP1B1-mediated drug resistance to prostate cancer DU145: Structure activity relationship

We previously discovered extrahepatic cytochrome P450 1B1 (CYP1B1) degraders able to overcome drug resistance toward docetaxel using a PROTACs technology, however, the underexplored structure activity relationships and poor water solubility posed a major hurdle in the development of CYP1B1 degraders. Herein, continuous efforts are made to develop more promising α-naphthoflavone (ANF)-derived chimeras for degrading CYP1B1. Guided by the strongest ANF-derived CYP1B1 degrader 3a we ever reported, 17 ANF analogues are designed and synthesized to evaluate the CYP1B1 degradation and resultant resistance reversal. In degrading CYP1B1 and sensitizing drug resistance, 4d with a 1, 5-cis triazole coupling mode at (C3') of B ring of ANF exhibited the similar potency as 3a carrying a 1, 4-trans triazole fragment at (C4') of B ring, but more obvious selectivity of 4d toward CYP1B1 over CYP1A2 is observed. When an oxygen was inserted into the linker of 4d, 4f demonstrated better water solubility, a more potent ability in degrading CYP1B1 and reversing drug resistance, and a promising selectivity. Collectively, a substitution position, an alkyne-azide cyclization and a liker type significantly affect the ability of ANF-thalidomide conjugates in eliminating drug resistance of CYP1B1-expressing DU145 (DU145/CY) cells to docetaxel via targeted CYP1B1 degradation.

MicroRNA Therapeutics in Cancer: Current Advances and Challenges

Simple Summary

Cancer is a complex disease associated with deregulation of numerous genes. In addition, redundant cellular pathways limit efficiency of monotarget drugs in cancer therapy. MicroRNAs are a class of gene expression regulators, which often function by targeting multiple genes. This feature makes them a double-edged sword (a) as attractive targets for anti-tumor therapy and concomitantly (b) as risky targets due to their potential side effects on healthy tissues. As for conventional antitumor drugs, nanocarriers have been developed to circumvent the problems associated with miRNA delivery to tumors. In this review, we highlight studies that have established the pre-clinical proof-of concept of miRNAs as relevant therapeutic targets in oncology. Particular attention was brought to new strategies based on nanovectorization of miRNAs as well as to the perspectives for their applications.

Abstract

The discovery of microRNAs (miRNAs) in 1993 has challenged the dogma of gene expression regulation. MiRNAs affect most of cellular processes from metabolism, through cell proliferation and differentiation, to cell death. In cancer, deregulated miRNA expression leads to tumor development and progression by promoting acquisition of cancer hallmark traits. The multi-target action of miRNAs, which enable regulation of entire signaling networks, makes them attractive tools for the development of anti-cancer therapies. Hence, supplementing downregulated miRNA by synthetic oligonucleotides or silencing overexpressed miRNAs through artificial antagonists became a common strategy in cancer research. However, the ultimate success of miRNA therapeutics will depend on solving pharmacokinetic and targeted delivery issues. The development of a number of nanocarrier-based platforms holds significant promises to enhance the cell specific controlled delivery and safety profile of miRNA-based therapies. In this review, we provide among the most comprehensive assessments to date of promising nanomedicine platforms that have been tested preclinically, pertaining to the treatment of selected solid tumors including lung, liver, breast, and glioblastoma tumors as well as endocrine malignancies. The future challenges and potential applications in clinical oncology are discussed.

Immunogenic Cell Death: A Step Ahead of Autophagy in Cancer Therapy

Immunogenic cell death (ICD) plays a major role in providing long lasting protective antitumor immunity by the chronic exposure of damage associated molecular patterns (DAMPs) in the tumor microenvironment (TME). DAMPs are essential for attracting immunogenic cells to the TME, maturation of DCs, and proper presentation of tumor antigens to the T cells so they can kill more cancer cells. Thus for the proper release of DAMPs, a controlled mechanism of cell death is necessary. Drug induced tumor cell killing occurs by apoptosis, wherein autophagy may act as a shield protecting the tumor cells and sometimes providing multi-drug resistance to chemotherapeutics. However, autophagy is required for the release of ATP as it remains one of the key DAMPs for the induction of ICD. In this review, we discuss the intricate balance between autophagy and apoptosis and the various strategies that we can apply to make these immunologically silent processes immunogenic. There are several steps of autophagy and apoptosis that can be regulated to generate an immune response. The genes involved in the processes can be regulated by drugs or inhibitors to amplify the effects of ICD and therefore serve as potential therapeutic targets.

The Effect of Gemcitabine on Cell Cycle Arrest and microRNA Signatures in Pancreatic Cancer Cells

BACKGROUND/AIM

Gemcitabine, an inhibitor of DNA synthesis, is the gold standard chemotherapeutic agent for pancreatic ductal adenocarcinoma (PDAC). MicroRNAs (miRNAs) play critical roles in cancers, including PDAC. However, less is known about the effect of gemcitabine on PDAC cells and miRNA expression in PDAC. We evaluated the effect of gemcitabine on the cell cycle of PDAC cells in vitro and in vivo and on the miRNA expression profile.

MATERIALS AND METHODS

Effects of gemcitabine on PK-1 and PK-9 cell growth were evaluated using a cell counting kit-8 assay. Xenografted mouse models were used to assess gemcitabine effects in vivo.

RESULTS

Gemcitabine inhibited the proliferation and tumour growth of PK-1 cells, and induced S phase cell cycle arrest. Numerous miRNAs were altered upon gemcitabine treatment of PK-1 cells and xenograft models.

CONCLUSION

Altered miRNAs may serve as potential therapeutic targets for improving the efficacy of gemcitabine in PDAC.

ncDRMarker: a computational method for identifying non-coding RNA signatures of drug resistance based on heterogeneous network

Background

Drug resistance is the primary cause of failure in the treatment of cancer. Identifying signatures of chemoresistance will help to overcome this problem. Current drug resistance studies focus on protein-coding genes and ignore non-coding RNAs (ncRNAs), rendering it a challenging task to systematically identify ncRNAs involved in drug resistance.

Methods

In this study, protein-protein, miRNA-target gene, miRNA-lncRNA interactions were integrated to construct a mRNA-miRNA-lncRNA network. Then, the random walk with restart (RWR) method was extended to the network for identifying ncRNA signatures of drug resistance. The leave-one-out cross validation (LOOCV) and receiver operating characteristic curve (ROC) were used to estimate the performance of ncDRMarker. Wilcoxon rank-sum test was used to validate the identified ncRNAs in NCI-60 cancer cell lines. KEGG pathway enrichment analysis was implemented to characterize the biological function of some identified ncRNAs.

Results

We performed this method on ten common clinical chemotherapy drugs and analyzed the results in detail. The region beneath the ROC was up to 0.881–0.951, which did not change significantly in the incomplete network, indicating the high performance and robustness of the method. Further, we confirmed the role of the identified ncRNAs in drug resistance, i.e., miR-92a-3p, a candidate chemoresistance ncRNA of tamoxifen and paclitaxel, can significantly classify cancer cell lines into sensitive or resistant to tamoxifen (or paclitaxel). We also dissected the mRNA-miRNA-lncRNA composite network and found that some hub ncRNAs, such as miR-124-3p, were involved in resistance of multiple drugs and engaged in many significant cancer-related pathways. Lastly, we have provided a ncDRMarker platform for users to identify candidate ncRNAs of drug resistance, which is available at http://bio-bigdata.hrbmu.edu.cn/ncDRMarker/index.

Conclusions

Our findings suggest that ncDRMarker is an effective computational technique for prioritizing candidate ncRNAs of drug resistance. Additionally, the identified ncRNAs could be targeted to overcome drug resistance and help realize individualized treatment.

Evaluation of miR-34a Effect on CCND1 mRNA Level and Sensitization of Breast Cancer Cell Lines to Paclitaxel

Background

A growing body of literature has revealed the effective role of miR-34a, as a tumor suppressor and regulator of expression of multiple targets in tumorigenesis and cancer progression. This study aimed at evaluating the potential effects of miR-34a alone or in combination with paclitaxel on breast cancer cells.

Methods

After miR-34a transduction by lentiviral vectors in two MCF-7 and MDA-MB-231 cell lines of breast cancer, effects of the elevated expression of miR-34a in the cell viability and the cell proliferation were determined using MTT assay in treated and untreated cells with paclitaxel. The mRNA level of the CCND1 (Cyclin D1)gene was then measured in the two cell lines using the qRT-PCR assay. Finally, the influence of miR-34a and paclitaxel on apoptosis and cell cycle progression were examined by flow cytometry.

Results

The CCND1 mRNA expression levels were significantly down-regulated by overexpressed lentiviral miR-34a in MCF-7 and MDA-MB-231 cells. Combined treatment by miR-34a and paclitaxel reduced the cell viability and proliferation compared to single-drug treatment. In addition, the cell cycle arrest appeared at two phases by the combination of miR-34a and paclitaxel in MDA-MB-231 cells.

Conclusion

Our results suggest that miR34a, in combination with paclitaxel, has a potential for decreasing the cell viability and proliferation. Moreover, it can reduce the expression of CCND1 mRNA independent of the paclitaxel effect.

microRNA -378a-3p Restrains the Proliferation of Retinoblastoma Cells but Promotes Apoptosis of Retinoblastoma Cells via Inhibition of FOXG1

Purpose

More recently, literature has emerged providing findings about the novelty of microRNAs (miR)-targeted therapeutics in the treatment of retinoblastoma (RB). The prime objective of this study was to identify the potential role of miR-378a-3p and its regulation in RB cells via forkhead box G1 (FOXG1).

Methods

The expression of miR-378a-3p and FOXG1 in the clinical RB tissues was determined using RNA quantitation and Western blot assays. The interaction between miR-378a-3p and FOXG1 was identified using dual luciferase reporter gene assay. The potential effects of miR-378a-3p on the RB cell biological processes were evaluated by conducting gain- and loss-of-function studies of miR-378a-3p and FOXG1, followed by cell viability, cell cycle progression, and apoptosis measurements. Furthermore, experiments were performed in nude mice to assess its effects on tumor formation.

Results

miR-378a-3p was poorly expressed, whereas FOXG1 was highly expressed in RB tissues and cells. miR-378a-3p bound to the FOXG1 3′ untranslated region and negatively modulated its expression. The overexpression of miR-378a-3p was found to decrease RB cell viability and to promote cell apoptosis in vitro, whereas overexpressed FOXG1 reversed the regulatory effects of miR-378a-3p on RB cellular behaviors. In nude mice, the restoration of miR-378a-3p by miR-378a-3p agomir was shown to play a role in the reduction of tumor volume and size relative to nude mice injected with negative control-agomir.

Conclusions

Our findings identified that increased miR-378a-3p exerted an inhibitory effect on RB cell proliferation by targeting FOXG1, suggesting the role of miR-378a-3p as a novel therapeutic target for RB.

MicroRNAs: As Critical Regulators of Tumor- Associated Macrophages

Emerging shreds of evidence suggest that tumor-associated macrophages (TAMs) modulate various hallmarks of cancer during tumor progression. Tumor microenvironment (TME) prime TAMs to execute important roles in cancer development and progression, including angiogenesis, matrix metalloproteinases (MMPs) secretion, and extracellular matrix (ECM) disruption. MicroRNAs (miRNAs) are critical epigenetic regulators, which modulate various functions in diverse types of cells, including macrophages associated with TME. In this review article, we provide an update on miRNAs regulating differentiation, maturation, activation, polarization, and recruitment of macrophages in the TME. Furthermore, extracellular miRNAs are secreted from cancerous cells, which control macrophages phenotypic plasticity to support tumor growth. In return, TAMs also secrete various miRNAs that regulate tumor growth. Herein, we also describe the recent updates on the molecular connection between tumor cells and macrophages. A better understanding of the interaction between miRNAs and TAMs will provide new pharmacological targets to combat cancer.

PTEN in osteosarcoma: Recent advances and the therapeutic potential

Osteosarcoma is the most common primary malignant bone tumor, predominantly occurring in children and adolescents. Despite treated with surgery and neoadjuvant chemotherapy, osteosarcoma has a high potential of local recurrence and lung metastasis. Overall survival rates for osteosarcoma have plateaued in the past four decades, therefore, identification of novel targets and development of more effective treatment strategies are urgent. Phosphatase and tensin homolog (PTEN) is a tumor suppressor gene that negatively regulates the phosphatidylinositol 3-kinase (PI3K)/ protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) pathway. Over half of clinical osteosarcoma samples presented loss or low expression of PTEN, which usually indicated an advanced stage of tumor and a poor prognosis. The expression of PTEN is regulated by epigenetic silence, transcription regulation, post-translational modifications, and protein interactions in osteosarcoma. Therefore, explicating regulations to restore the anti-tumor function of PTEN might provide novel targeted therapies for osteosarcoma. Preclinical evidence suggested directly targeting the altered PTEN in osteosarcoma was promising. Current clinical application of PTEN related therapies in osteosarcoma are PI3K/mTOR inhibitors, and these drugs have shown the favorable efficacy in patients with advanced osteosarcoma.

MicroRNA200a enhances antitumor effects in combination with doxorubicin in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is often treated with doxorubicin. MicroRNAs have been shown to have important regulatory roles in cancer and serve as a target in chemoresistance. In this study, we investigated the effects of specific microRNA-200a (miR-200a) on HCC tumor cell growth and effect of doxorubicin-mediated cytotoxicity. Our results show miR-200a is downregulated in human HCC and HCC tumor cell lines. Increasing miR-200a expression inhibited HCC growth and synergized with the antitumor effects of doxorubicin. Inhibiting endogenous miR-200a promoted tumor growth and chemotherapeutic resistance. Increasing miR-200a expression inhibited tumor metabolism (ATP production, mitochondrial respiration, glycolysis), while inhibition of endogenous miR-200a reversed these effects. MiR-200a expression also increased autophagy and synergized with doxorubicin-mediated cytotoxicity. This study identifies a novel role of miR-200a in potentiating doxorubicin-mediated therapeutic effects in HCC.

Exosomal miR-200c suppresses chemoresistance of docetaxel in tongue squamous cell carcinoma by suppressing TUBB3 and PPP2R1B

BACKGROUND

Chemoresistance is the main challenge for treating tongue squamous cell carcinoma (TSCC). MiR-200c is an important regulator of chemoresistance. Exosomes are a promising molecule-delivery system for cancer treatment. Thus, this study aimed to investigate the role of miR-200c in chemoresistance of TSCC and whether exosomes could effectively deliver miR-200c to chemo-resistant cells and regulate cellular activities.

RESULTS

The results showed that the downregulation of miR-200c increased resistance to DTX, migration, and invasion and decreased apoptosis, which was reversed by the overexpression of miR-200c. The NTECs-derived exosomes transported miR-200c to HSC-3DR, increasing the sensitivity to DTX in vitro and in vivo. Also, epithelial-to-mesenchymal transition (EMT) and DNA damage responses were involved in DTX resistance. Furthermore, miR-200c regulated DTX resistance by targeting TUBB3 and PPP2R1B.

CONCLUSION

Exosome-mediated miR-200c delivery may be an effective and promising strategy to treat chemoresistance in TSCC.

METHODS

Docetaxel (DTX) resistant HSC-3 cells (HSC-3DR) were transfected with miR-200c lentivirus and cocultured with exosomes derived from normal tongue epithelial cells (NTECs) that were overexpressed with miR-200c. The roles of miR-200c and exosomal miR-200c in vitro and in vivo were determined by RNA-Seq, qRT-PCR, western blots, transmission electron microscopy, and flow cytometry, fluorescence, CCK8, Transwell, and wound healing assays.

Caffeic Acid Attenuates Multi-Drug Resistance in Cancer Cells by Inhibiting Efflux Function of Human P-glycoprotein

: Multidrug resistance (MDR) is a complicated ever-changing problem in cancer treatment, and P-glycoprotein (P-gp), a drug efflux pump, is regarded as the major cause. In the way of developing P-gp inhibitors, natural products such as phenolic acids have gotten a lot of attention recently. The aim of the present study was to investigate the modulating effects and mechanisms of caffeic acid on human P-gp, as well as the attenuating ability on cancer MDR. Calcein-AM, rhodamine123, and doxorubicin were used to analyze the interaction between caffeic acid and P-gp, and the ATPase activity of P-gp was evaluated as well. Resistance reversing effects were revealed by SRB and cell cycle assay. The results indicated that caffeic acid uncompetitively inhibited rhodamine123 efflux and competitively inhibited doxorubicin efflux. In terms of P-gp ATPase activity, caffeic acid exhibited stimulation in both basal and verapamil-stimulated activity. The combination of chemo drugs and caffeic acid resulted in decreased IC₅₀ in ABCB1/Flp-In^TM-293 and KB/VIN, indicating that the resistance was reversed. Results of molecular docking suggested that caffeic acid bound to P-gp through GLU74 and TRY117 residues. The present study demonstrated that caffeic acid is a promising candidate for P-gp inhibition and cancer MDR attenuation.

Intercellular Crosstalk Via Extracellular Vesicles in Tumor Milieu as Emerging Therapies for Cancer Progression

:

Increasing evidence has suggested that extracellular vesicles (EV) mediated bidirectional transfer of functional molecules (such as proteins, different types of RNA, and lipids) between cancer cells and tumor stromal cells (immune cells, endothelial cells, fibroblasts, stem cells) and strongly contributed to the reinforcement of cancer progression. Thus, intercellular EV-mediated signaling in tumor microenvironment (TME) is essential in the modulation of all processes that support and promote tumor development like immune suppression, angiogenesis, invasion and metastasis, and resistance of tumor cells to anticancer treatments.

:

Besides EV potential to revolutionize our understanding of the cancer cell-stromal cells crosstalk in TME, their ability to selectively transfer different cargos to recipient cells has created excitement in the field of tumortargeted delivery of specific molecules for anticancer treatments. Therefore, in tight connection with previous findings, this review brought insight into the dual role of EV in modulation of TME. Thus, on one side EV create a favorable phenotype of tumor stromal cells for tumor progression; however, as a future new class of anticancer drug delivery systems EV could re-educate the TME to overcome main supportive processes for malignancy progression.

Aberrant Expression of the miR-181b/miR-222 after Hematopoietic Stem Cell Transplantation in Patients with Acute Myeloid Leukemia

Recently, dysregulated expression of various micro RNAs has been reported in hematologic malignancies, especially AML disease which affects normal hematopoiesis in these patients and thereby contribute to clinical outcome of AML patients, associated with either poor or favorable prognosis. Herein, we evaluated the expression of miR-181b and miR-222 in acute myeloid leukemia patients and correlation with response to therapy after hematopoietic stem cell transplantation. Eighty newly diagnosed AML patients and 80 healthy controls were recruited. The expression of miR-181b and miR-222 was evaluated by real-time SYBR Green PCR method. miR-181b gene expression was significantly increased (4.7 fold) whereas miR-222 was decreased (18.3 fold) in AML patients compared to controls (P = 0.03 and P < 0.001, respectively). Both miR-181b and miR-222 were not associated with response to treatment (P > 0.05). Also, miR-181b and miR-222 were not differentially expressed in AML patients with M3 compared to non-M3 FAB subtypes (P > 0.05). miR-181b and miR-222 are aberrantly expressed in AML patients and their baseline level is not associated with response to treatment.

microRNA-10b confers cisplatin resistance by activating AKT/mTOR/P70S6K signaling via targeting PPARγ in esophageal cancer

It is well known that the acquisition of chemoresistance is a major obstacle for the effective treatment of human cancers. It is reported that microRNAs (miRNAs) are implicated in chemotherapy resistance of various malignancies. miR-10b was previously proved as an oncogene in multiple malignancies, including esophageal cancer. However, its biological significance in regulating cisplatin (DDP) resistance in esophageal cancer is still elusive. Here, we observed that miR-10b expression was upregulated and peroxisome proliferator-activated receptor-γ (PPARγ) expression was downregulated in esophageal cancer tumor tissues and cells. PPARγ was proved as a functional target of miR-10b. Moreover, suppression of miR-10b enhanced the chemosensitivity of esophageal cancer cells to DDP in vitro and in vivo. In addition, PPARγ-mediated DDP sensitivity was weakened by miR-10b overexpression. Furthermore, miR-10b-activated AKT/mTOR/p70S6K signaling pathway through targeting PPARγ. Inactivation of AKT/mTOR/p70S6K by AKT inhibitor (GSK690693) attenuated miR-10b-induced DDP resistance in esophageal cancer cells. Taken together these observation, miRNA-10b-mediated PPARγ inhibition enhanced DDP resistance by activating the AKT/mTOR/P70S6K signaling in esophageal cancer, suggesting a potential target to improve therapeutic response of patients with esophageal cancer to DDP.

MicroRNAs as possible indicators of drug sensitivity in breast cancer cell lines

MicroRNAs (miRNAs) regulate gene expression post-transcriptionally. In this way they might influence whether a cell is sensitive or resistant to a certain drug. So far, only a limited number of relatively small scale studies comprising few cell lines and/or drugs have been performed. To obtain a broader view on miRNAs and their association with drug response, we investigated the expression levels of 411 miRNAs in relation to drug sensitivity in 36 breast cancer cell lines. For this purpose IC₅₀ values of a drug screen involving 34 drugs were associated with miRNA expression data of the same breast cancer cell lines. Since molecular subtype of the breast cancer cell lines is considered a confounding factor in drug association studies, multivariate analysis taking subtype into account was performed on significant miRNA-drug associations which retained 13 associations. These associations consisted of 11 different miRNAs and eight different drugs (among which Paclitaxel, Docetaxel and Veliparib). The taxanes, Paclitaxel and Docetaxel, were the only drugs having miRNAs in common: hsa-miR-187-5p and hsa-miR-106a-3p indicative of drug resistance while Paclitaxel sensitivity alone associated with hsa-miR-556-5p. Tivantinib was associated with hsa-let-7d-5p and hsa-miR-18a-5p for sensitivity and hsa-miR-637 for resistance. Drug sensitivity was associated with hsa-let-7a-5p for Bortezomib, hsa-miR-135a-3p for JNJ-707 and hsa-miR-185-3p for Panobinostat. Drug resistance was associated with hsa-miR-182-5p for Veliparib and hsa-miR-629-5p for Tipifarnib. Pathway analysis for significant miRNAs was performed to reveal biological roles, aiding to find a potential mechanistic link for the observed associations with drug response. By doing so hsa-miR-187-5p was linked to the cell cycle G2-M checkpoint in line with this checkpoint being the target of taxanes. In conclusion, our study shows that miRNAs could potentially serve as biomarkers for intrinsic drug resistance and that pathway analyses can provide additional information in this context.

Cancer drug resistance: A fleet to conquer

Cancer is a disease that claims millions of lives each year across the world. Despite advancement in technologies and therapeutics for treating the disease, these modes are often found to turn ineffective during the course of treatment. The resistance against drugs in cancer patients stems from multiple factors, which constitute genetic heterogeneity like gene mutations, tumor microenvironment, exosomes, miRNAs, high rate of drug efflux from cells, and so on. This review attempts to collate all such known and reported factors that influence cancer drug resistance and may help researchers with information that might be useful in developing better therapeutics in near future to enable better management of several cancers across the world.

Exosome-transmitted miR-128-3p increase chemosensitivity of oxaliplatin-resistant colorectal cancer

Background

Oxaliplatin resistance is a major challenge for treatment of advanced colorectal cancer (CRC). Both acquisition of epithelial-mesenchymal transition (EMT) and suppressed drug accumulation in cancer cells contributes to development of oxaliplatin resistance. Aberrant expression of small noncoding RNA, miR-128-3p, has been shown to be a key regulator in tumorigenesis and cancer development. However, its roles in the progression of CRC and oxaliplatin-resistance are largely unknown.

Methods

Oxaliplatin-resistant CRC and normal intestinal FHC cells were transfected with a miR-128-3p expression lentivirus. After transfection, FHC-derived exosomes were isolated and co-cultured with CRC cells. miR-128-3p expression in resistant CRC cells, FHC cells, and exosomes was quantified by quantitative real-time PCR (RT-qPCR). The mRNA and protein levels of miR-128-3p target genes in resistant CRC cells were quantified by RT-qPCR and western blot, respectively. The effects of miR-128-3p on CRC cell viability, apoptosis, EMT, motility and drug efflux were evaluated by CCK8, flow cytometry, Transwell and wound healing assays, immunofluorescence, and atomic absorption spectrophotometry. Xenograft models were used to determine whether miR-128-3p loaded exosomes can re-sensitize CRC cells to oxaliplatin in vivo.

Results

In our established stable oxaliplatin-resistant CRC cell lines, in vitro and vivo studies revealed miR-128-3p suppressed EMT and increased intracellular oxaliplatin accumulation. Importantly, our results indicated that lower miR-128-3p expression was associated with poor oxaliplatin response in advanced human CRC patients. Moreover, data showed that miR-128-3p-transfected FHC cells effectively packaged miR-128-3p into secreted exosomes and mediated miR-128-3p delivery to oxaliplatin-resistant cells, improving oxaliplatin response in CRC cells both in vitro and in vivo. In addition, miR-128-3p overexpression up-regulated E-cadherin levels and inhibited oxaliplatin-induced EMT by suppressing Bmi1 expression in resistant cells. Meanwhile, it also decreased oxaliplatin efflux through suppressed expression of the drug transporter MRP5.

Conclusion

Our results demonstrate that miR-128-3p delivery via exosomes represents a novel strategy enhancing chemosensitivity in CRC through negative regulation of Bmi1 and MRP5. Moreover, miR-128-3p may be a promising diagnostic and prognostic marker for oxaliplatin-based chemotherapy.

Electronic supplementary material

The online version of this article (10.1186/s12943-019-0981-7) contains supplementary material, which is available to authorized users.

Co-delivery of miR-181a and melphalan by lipid nanoparticles for treatment of seeded retinoblastoma

Melphalan is an efficient chemotherapeutic agent that is currently used to treat retinoblastoma (Rb); however, the inherent risk of immunogenicity and the hazardous integration of this drug in healthy cells is inevitable. MicroRNAs are short non-coding single-stranded RNAs that affect a vast range of biological processes. Previously, we focused on the regulatory role of miR-181a during cancer development and progression. In this manuscript, 171 nm switchable lipid nanoparticles (LNP) co-delivered melphalan and miR-181a with encapsulation efficiencies of 93%. Encapsulation of melphalan in LNP significantly improved its therapeutic efficiency. Gene analysis shows that miR-181a decreases the expression of anti-proliferative gene MAPK1 and anti-apoptotic gene Bcl-2, but significantly increased the expression of pro-apoptotic gene BAX. Our results suggest that the two agents have a complementary effect in reducing the viability of cultured Rb cells (primary and cell line) and decreasing Rb cell counts in an in-vivo xenograft Rb model in rats. Our results suggest that the proposed co-delivery technique significantly increases the therapeutic impact, allows for lower administration of melphalan, and consequently, could minimize the cytotoxic side-effects of this drug.

The role and mechanisms of action of microRNAs in cancer drug resistance

MicroRNAs (miRNAs) are small non-coding RNAs with a length of about 19–25 nt, which can regulate various target genes and are thus involved in the regulation of a variety of biological and pathological processes, including the formation and development of cancer. Drug resistance in cancer chemotherapy is one of the main obstacles to curing this malignant disease. Statistical data indicate that over 90% of the mortality of patients with cancer is related to drug resistance. Drug resistance of cancer chemotherapy can be caused by many mechanisms, such as decreased antitumor drug uptake, modified drug targets, altered cell cycle checkpoints, or increased DNA damage repair, among others. In recent years, many studies have shown that miRNAs are involved in the drug resistance of tumor cells by targeting drug-resistance-related genes or influencing genes related to cell proliferation, cell cycle, and apoptosis. A single miRNA often targets a number of genes, and its regulatory effect is tissue-specific. In this review, we emphasize the miRNAs that are involved in the regulation of drug resistance among different cancers and probe the mechanisms of the deregulated expression of miRNAs. The molecular targets of miRNAs and their underlying signaling pathways are also explored comprehensively. A holistic understanding of the functions of miRNAs in drug resistance will help us develop better strategies to regulate them efficiently and will finally pave the way toward better translation of miRNAs into clinics, developing them into a promising approach in cancer therapy.

Bazedoxifene as a novel GP130 inhibitor for Colon Cancer therapy

Background

Interleukin-11 (IL-11), a dominant IL-6 family cytokine, is involved in tumorigenesis, tumor progression and differentiation in colon cancer cells. IL-11 signaling has been recently identified as a potential therapeutic target in colon cancer. Bazedoxifene, a third- generation selective estrogen modulator approved by the Food and Drug Administration (FDA), is a novel inhibitor of IL-11/GP130 signaling discovered by docking modeling.

Methods

In this study, the inhibition efficacy of bazedoxifene in colon cancer cells and its potential mechanism were investigated in vitro and in vivo by using MTT cell viability assay, BrdU cell proliferation assay, colony formation assay, wound-healing/cell migration assay, immunofluorescence, western blot assay and the mouse xenograft tumor model.

Results

Bazedoxifene inhibits phosphorylation of signal transducer and activator of transcription 3 (p-STAT3) and its nuclear translocation induced by IL-11 in colon cancer cells. It also inhibits p-STAT3 induced by IL-6 and IL-11 but not by OSM or STAT1 phosphorylation induced by INF-γ in human colon cancer cells. In addition, bazedoxifene can significantly inhibit phosphorylation of AKT and STAT3 downstream targets. Furthermore, bazedoxifene alone or together with oxaliplatin can significantly induce apoptosis, inhibit cell viability, cell colony formation and cell migration in colon cancer cells. Knock-down of IL-11R can reduce the sensitivity of colon cancer cells to bazedoxifene. IL-11 can reduce the efficacy of oxaliplatin-mediated inhibition of cell viability. Consistent with in vitro findings, bazedoxifene alone also attenuated HCT-15 xenograft tumor burden and reduced p-STAT3, p-AKT and p-ERK in vivo. Its combination with oxaliplatin attenuated DLD-1 xenograft tumor burden and reduced p-STAT3 in vivo.

Conclusions

Taken together, these results support bazedoxifene as a novel and effective therapeutic agent targeting IL-11/GP130 signaling for human colorectal cancer therapy.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1072-8) contains supplementary material, which is available to authorized users.

Hyaluronic acid-modified cationic nanoparticles overcome enzyme CYP1B1-mediated breast cancer multidrug resistance

Aim: Enzyme CYP1B1 (CYP1B1) is usually overexpressed in multidrug resistance (MDR) breast cancer cells, which could metabolically inactivate docetaxel (DTX). Materials & methods: The cationic core–shell nanoparticles (hyaluronic acid/polyethyleneimine nanoparticles [HA/PEI NPs]) modified with hyaluronic acid (HA) were developed and coloaded with DTX and α-napthtoflavone (ANF, a CYP1B1 inhibitor) to overcome MDR in breast cancer induced by CYP1B1. Physicochemical characterization, MDR reversing effect in vitro and pharmacokinetics in vivo of HA/PEI NPs were evaluated. Results: The HA/PEI NPs exhibited spherical morphology with size of (193.6 ± 3.1) nm. The HA/PEI NPs could reverse MDR effectively by downregulating the expression of CYP1B1. The HA/PEI NPs improved the bioavailability of DTX. Conclusion: The HA/PEI NPs might be a promising strategy to overcome CYP1B1-mediated breast cancer MDR.

Dendrimers Show Promise for siRNA and microRNA Therapeutics

The lack of an appropriate intracellular delivery system for therapeutic nucleic acids (TNAs) is a major problem in molecular biology, biotechnology, and medicine. A relatively new class of highly symmetrical hyperbranched polymers, called dendrimers, shows promise for transporting small TNAs into both cells and target tissues. Dendrimers have intrinsic advantages for this purpose: their physico-chemical and biological properties can be controlled during synthesis, and they are able to transport large numbers of TNA molecules that can specifically suppress the expression of single or multiple targeted genes. Numerous chemical modifications of dendrimers extend the biocompatibility of synthetic materials and allow targeted vectors to be designed for particular therapeutic purposes. This review summarizes the latest experimental data and trends in the medical application of various types of dendrimers and dendrimer-based nanoconstructions as delivery systems for short small interfering RNAs (siRNAs) and microRNAs at the cell and organism levels. It provides an overview of the structural features of dendrimers, indicating their advantages over other types of TNA transporters.

MiR-150-3p targets SP1 and suppresses the growth of glioma cells

Glioma has been considered as one of the most prevalent and common malignancy of the nervous system; however, the underlying mechanisms that are responsible for the occurrence and development of glioma still remain largely unknown. Amounting evidence highlights the critical regulatory function of miRNAs in carcinogenesis. Here, we showed that the expression of miR-150-3p was significantly decreased in glioma tissues and cell lines. Suppressed expression of miR-150-3p was associated with the lymph node metastasis of the glioma patients. Overexpression of miR-150-3p significantly inhibited the proliferation of glioma cells. Molecular study uncovered that the transcription factor specificity protein 1 (SP1) was identified as one of the targets of miR-150-3p Highly expressed miR-150-3p in glioma cells significantly decreased both the mRNA and protein levels of SP1. Consistently, the abundance of phosphatase and tension homolog deleted on chromosome ten (PTEN), a negative downstream target of SP1, was increased with the ectopic miR-150-3p Collectively, these results suggested that miR-150-3p suppressed the growth of glioma cells partially via regulating SP1 and possibly PTEN.

Negative Regulation of PTEN by MicroRNA-221 and Its Association with Drug Resistance and Cellular Senescence in Lung Cancer Cells

Objective

Chemotherapy is the routine method for treating many cancers, but long-term treatment may result in developing resistance to the drugs. The aim of this study was to identify whether noncoding RNAs play a role in drug resistance and how they affect drug resistance.

Materials and Methods

The expression levels of miR-221 in different lung cancer cell lines H226, H1299, and A549 were measured. H1299 and A549 cell lines were transfected to overexpress and downexpress miR-221, and cell viability and cell senescence were determined. The PTEN/Akt pathway was then examined by real-time polymerase chain reaction and Western blot analysis.

Results

MiR-221 together with proteins MDR1 and ABCG2 was upregulated in Cisplatin-resistant A549 lung cancer cells. Anti-miR-221 inhibits proliferation and induces senescence in lung cancer cells. PTEN/Akt pathway axis was identified as a target of drug resistance induced by miR-221.

Conclusion

Our results revealed that miR-221 is an important regulator for chemotherapy sensitivity and showed miR-221 as a potential target for drug sensitization.

PiwiRNA-651 as marker of treatment response and survival in classical Hodgkin lymphoma

PiwiRNAs, small non-coding RNAs processed by Piwi proteins, are involved in maintaining genome stability in germline cells. Recently, piwiRNA expression has been identified in some tumors. We have examined the potential reactivation of the Piwi/piwiRNA pathway in classical Hodgkin lymphoma (cHL). We found that Piwi proteins and three selected piwiRNAs, including piR-651, were expressed in cHL patients and cell lines, indicating that the Piwi/piwiRNA pathway is active in cHL. Interestingly, low levels of piR-651 were associated with lack of complete response to first-line treatment, as well as shorter disease-free and overall survival in a cohort of 94 cHL patients. At diagnosis, piR-651 was underexpressed in cHL serum samples compared to healthy controls, while after complete remission, piR-651 levels increased to levels similar to healthy controls. This is the first evidence that piwiRNAs are active in tumor and serum samples and impact prognosis in cHL.

Towards Comprehension of the ABCB1/P-Glycoprotein Role in Chronic Myeloid Leukemia

Abstract: The introduction of imatinib (IM), a BCR-ABL1 tyrosine kinase inhibitor (TKI), has represented a significant advance in the first-line treatment of chronic myeloid leukemia (CML). However, approximately 30% of patients need to discontinue IM due to resistance or intolerance to this drug. Both resistance and intolerance have also been observed in treatment with the second-generation TKIs-dasatinib, nilotinib, and bosutinib-and the third-generation TKI-ponatinib. The mechanisms of resistance to TKIs may be BCR-ABL1-dependent and/or BCR-ABL1-independent. Although the role of efflux pump P-glycoprotein (Pgp), codified by the ABCB1 gene, is unquestionable in drug resistance of many neoplasms, a longstanding question exists about whether Pgp has a firm implication in TKI resistance in the clinical scenario. The goal of this review is to offer an overview of ABCB1/Pgp expression/activity/polymorphisms in CML. Understanding how interactions, associations, or cooperation between Pgp and other molecules-such as inhibitor apoptosis proteins, microRNAs, or microvesicles-impact IM resistance risk may be critical in evaluating the response to TKIs in CML patients. In addition, new non-TKI compounds may be necessary in order to overcome the resistance mediated by Pgp in CML.

WBSCR22 confers oxaliplatin resistance in human colorectal cancer

Human WBSCR22 gene is involved in tumor metastasis, cell growth and invasion, however, its role in chemosensitivity to antitumor agents remains unknown. In this study, we analyzed the TCGA cohort and found the expression of WBSCR22 was significantly elevated in human colorectal cancer (CRC) tissue. WBSCR22 could be served as an independent risk predictor for overall survival (OS), and up-regulated WBSCR22 could predict unfavorable OS for CRC patients. Knockdown of WBSCR22 significantly sensitized CRC cells to oxaliplatin in vitro and in vivo, while overexpression of WBSCR22 led to cellular resistance to oxaliplatin treatment. Although WBSCR22 knockdown did not change cell cycle, it increased the oxaliplatin-induced cellular apoptosis. WBSCR22 knockdown augmented the oxaliplatin-induced intracellular reactive oxygen species (ROS) production and ROS-induced 8-oxoguanine (8-oxoG) oxidative lesion accumulation, likely sensitizing oxaliplatin treatment. These results demonstrate that WBSCR22 is involved in CRC resistance to oxaliplatin, suggesting WBSCR22 may represent a novel oxaliplatin resistance biomarker as well as a potentail target for CRC therapeutics.

MicroRNA-212/ABCG2-axis contributes to development of imatinib-resistance in leukemic cells

BCR-ABL-independent resistance against tyrosine kinase inhibitor is an emerging problem in therapy of chronic myeloid leukemia. Such drug resistance can be linked to dysregulation of ATP-binding cassette (ABC)-transporters leading to increased tyrosine kinase inhibitor efflux, potentially caused by changes in microRNA expression or DNA-methylation. In an in vitro-imatinib-resistance model using K-562 cells, microRNA-212 was found to be dysregulated and inversely correlated to ABC-transporter ABCG2 expression, targeting its 3'-UTR. However, the functional impact on drug sensitivity remained unknown. Therefore, we performed transfection experiments using microRNA-mimics and -inhibitors and investigated their effect on imatinib-susceptibility in sensitive and resistant leukemic cell lines. Under imatinib-treatment, miR-212 inhibition led to enhanced cell viability (p = 0.01), reduced apoptosis (p = 0.01) and cytotoxicity (p = 0.03). These effects were limited to treatment-naïve cells and were not observed in cells, which were resistant to various imatinib-concentrations (0.1 μM to 2 μM). Further analysis in treatment-naïve cells revealed that miR-212 inhibition resulted in ABCG2 upregulation and increased ABCG2-dependent efflux. Furthermore, we observed miR-212 promoter hypermethylation in 0.5 and 2 μM IM-resistant sublines, whereas ABCG2 methylation status was not altered. Taken together, the miR-212/ABCG2-axis influences imatinib-susceptibility contributing to development of imatinib-resistance. Our data reveal new insights into mechanisms initiating imatinib-resistance in leukemic cells.