Research progress on lung cancer stem cells in epidermal growth factor receptor–tyrosine kinase inhibitor targeted therapy resistance in lung adenocarcinoma

Lung cancer is the leading cause of cancer-related deaths globally.In recent years,with the widespread use of genetic testing,epidermal growth factor receptor–tyrosine kinase inhibitor(EGFR-TKI)–targeted drugs have been efficacious to patients with lung adenocarcinoma exhibiting EGFR mutations.However,resistance to treatment is inevitable and eventually leads to tumor progression,recurrence,and reduction in the overall treatment efficacy.Lung cancer stem cells play a crucial role in the development of resistance toward EGFR-TKI–targeted therapy for lung adenocarcinoma.Lung cancer stem cells possess self-renewal,multilineage differentiation,and unlimited proliferation capabilities,which efficiently contribute to tumor formation and ultimately lead to tumor recurrence andmetastasis.In this study,we evaluated the origin,markers,stemness index,relevant classic studies,resistance mechanisms,related signaling pathways,and strategies for reversing lung cancer stem cell resistance to EGFR-TKIs to provide new insights on delaying or reducing resistance and to improve the treatment efficacy of patients with EGFR-mutated lung adenocarcinoma in the future.

Mesenchymal stem cells-based drug delivery systems for diabetic foot ulcer:A review

The complication of diabetes,which is known as diabetic foot ulcer(DFU),is a significant concern due to its association with high rates of disability and mortality.It not only severely affects patients’quality of life,but also imposes a substantial burden on the healthcare system.In spite of efforts made in clinical practice,treating DFU remains a challenging task.While mesenchymal stem cell(MSC)therapy has been extensively studied in treating DFU,the current efficacy of DFU healing using this method is still inadequate.However,in recent years,several MSCs-based drug delivery systems have emerged,which have shown to increase the efficacy of MSC therapy,especially in treating DFU.This review summarized the application of diverse MSCs-based drug delivery systems in treating DFU and suggested potential prospects for the future research.

Human bone marrow mesenchymal stem cell-derived exosomes loaded with gemcitabine inhibit pancreatic cancer cell proliferation by enhancing apoptosis

BACKGROUND Pancreatic cancer remains one of the most lethal malignancies,and has limited effective treatment.Gemcitabine(GEM),a chemotherapeutic agent,is commonly used for clinical treatment of pancreatic cancer,but it has characteristics of low drug delivery efficiency and significant side effects.The study tested the hypothesis that human bone marrow mesenchymal stem cell(MSC)-derived exosomes loaded with GEM(Exo-GEM)would have a higher cytotoxicity against human pancreatic cancer cells by enhancing their apoptosis.AIM To investigate the cytotoxicity of MSC-derived Exo-GEM against pancreatic cancer cells in vitro.METHODS Exosomes were isolated from MSCs and characterized by transmission electron microscopy and nanoparticle tracking analysis.Exo-GEM through electroporation,sonication,or incubation,and the loading efficiency was evaluated.The cytotoxicity of Exo-GEM or GEM alone against human pancreatic cancer Panc-1 and MiaPaca-2 cells was assessed by MTT and flow cytometry assays.RESULTS The isolated exosomes had an average size of 76.7 nm.The encapsulation efficacy and loading efficiency of GEM by electroporation and sonication were similar and significantly better than incubation.The cytotoxicity of Exo-GEM against pancreatic cancer cells was stronger than free GEM and treatment with 0.02μM Exo-GEM significantly reduced the viability of both Panc-1 and MiaPaca-2 cells.Moreover,Exo-GEM enhanced the frequency of GEMinduced apoptosis in both cell lines.CONCLUSION Human bone marrow MSC-derived Exo-GEM have a potent cytotoxicity against human pancreatic cancer cells by enhancing their apoptosis,offering a promising drug delivery system for improving therapeutic outcomes.

Charcoal Nanoparticles as a Delivery System for Doxorubicin and Sorafenib in Treatment of Hepatocellular Carcinoma

Background: Hepatocellular carcinoma (HCC) is the most common type of liver cancer and one of the leading causes of cancer-related death worldwide. Advanced HCC displays strong resistance to chemotherapy, and traditional chemotherapy drugs do not achieve satisfactory therapeutic efficacy. The delivery of therapeutic compounds to the target site is a major challenge in the treatment of many diseases. Objective: This study aims to evaluate activated charcoal nanoparticles as a drug delivery system for anticancer agents (Sorafenib and Doxorubicin) in Hepatocellular Cancer Stem Cells. Method: The percent efficiency of entrapment (% EE) of the doxorubicin and sorafenib entrapped onto the activated charcoal was obtained by determining the free doxorubicin and sorafenib concentration in the supernatant-prepared solutions. Then the characterizations of nanoparticles were formed by determination of the particle size distribution, zeta potential, and polydispersity index (PDI). The anticancer activity of activated Charcoal, Doxorubicin-ACNP, sorafenib-ACNP, free doxorubicin, and free sorafenib solutions was measured based on cell viability percentage in HepG2 cell lines (ATCC-CCL 75). In vitro RBC’s toxicity of Doxorubicin/sorafenib loaded charcoal was estimated by hemolysis percentage. Results: The synthesized Doxorubicin-ACNP and Sorafenib-ACNP were evaluated and their physiochemical properties were also examined. Essentially, the percent Efficiency of Entrapment (EE %) was found to be 87.5% and 82.66% for Doxorubicin-ACNP and Sorafenib-ACNP, respectively. The loading capacity was 34.78% and 24.31% for Doxorubicin-ACNP and Sorafenib-ACNP. Using the Dynamic Light scattering [DLS] for the determination of the hydrodynamic size and surface zeta potential, a narrow sample size distribution was obtained of (18, 68, and 190 nm for charcoal, 105, 255, and 712 nm for doxorubicin, and 91, 295, and 955 nm for sorafenib), respectively. A surface charge of −13.2, −15.6 and −17 was obtained for charcoal, doxorubicin/charcoal, and sorafenib/charcoal nanoparticles. The cytotoxic activity of Doxorubicin-ACNP and Sorafenib-ACNP was evaluated in-vitro against HepG2 cell lines and it was observed that Drug loaded ACNP improved anticancer activity when compared to Doxorubicin or Sorafenib alone. Moreover, testing the toxicity potential of DOX-ACNP and Sorafenib-ACNP showed a significant reduction in the hemolysis of red blood cells when compared to Doxorubicin and Sorafenib alone. Conclusion: In conclusion, it is notable to state that this study is regarded as the first to investigate the use of Activated charcoal for the loading of Doxorubicin and Sorafenib for further use in the arena of hepatocellular carcinoma. Doxorubicin-ACNP and Sorafenib-ACNP showed noteworthy anticancer activity along with a reduced potential of RBCs hemolysis rendering it as an efficacious carrier with a low toxicity potential.

Research Progress of Breast Cancer Stem Cell Stemness and Breast Cancer Recurrence

Currently, breast cancer is the most common malignant tumour in Chinese women with a high incidence rate, and recurrence and metastasis are the main reasons affecting survival. Breast Cancer Stem Cells (BCSCs) are stem cells capable of continuous regeneration in vivo with strong self-renewal ability and multidirectional differentiation potential, which are highly tumourigenic and insensitive to radiotherapy and chemotherapy, and are highly susceptible to breast cancer recurrence. Therefore, exploring the stemness of BCSCs and their mechanism associated with recurrence is important for developing new therapeutic strategies, improving therapeutic efficacy, and improving patient prognosis.

Advances of nanotechnology applied to cancer stem cells

Cancer stem cells(CSCs)are a small proportion of the cells that exist in cancer tissues.They are considered to be the culprit of tumor genesis,development,drug resistance,metastasis and recurrence because of their self-renewal,proliferation,and differentiation potential.The elimination of CSCs is thus the key to cure cancer,and targeting CSCs provides a new method for tumor treatment.Due to the advantages of controlled sustained release,targeting and high biocompatibility,a variety of nanomaterials are used in the diagnosis and treatments targeting CSCs and promote the recognition and removal of tumor cells and CSCs.This article mainly reviews the research progress of nanotechnology in sorting CSCs and nanodrug delivery systems targeting CSCs.Furthermore,we identify the problems and future research directions of nanotechnology in CSC therapy.We hope that this review will provide guidance for the design of nanotechnology as a drug carrier so that it can be used in clinic for cancer therapy as soon as possible.

Hepatic cancer stem cells and drug resistance: Relevance in targeted therapies for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of most common malignancies in the world. Systemic treatments for HCC, particularly for advanced stages, are limited by the drug resistance phenomenon which ultimately leads to therapy failure. Recent studies have indicated an association between drug resistance and the existence of the cancer stem cells (CSCs) as tumor initiating cells. The CSCs are resistant to conventional chemotherapies and might be related to the mechanisms of the ATP Binding Cassette (ABC) transporters and alterations in the CSCs signaling pathways. Therefore, to contribute to the development of new HCC treatments, further information on the characterization of CSCs, the modulation of the ABC transporters expression and function and the signaling pathway involved in the self renewal, initiation and maintenance of the cancer are required. The combination of transporters modulators/inhibitors with molecular targeted therapies may be a potent strategy to block the tumoral progression. This review summarizes the association of CSCs, drug resistance, ABC transporters activities and changes in signaling pathways as a guide for future molecular therapy for HCC.

Persistence of side population cells with high drug efflux capacity in pancreatic cancer

AIM: To investigate the persistence of side population (SP) cells in pancreatic cancer and their role and mechanism in the drug resistance. METHODS: The presentation of side population cells in pancreatic cancer cell line PANC-1 and its proportion change when cultured with Gemcitabine, was detected by Hoechst 33342 staining and FACS analysis. The expression of ABCB1 and ABCG2 was detected by real- time PCR in either SP cells or non-SP cells. RESULTS: SP cells do exist in PANC-1, with a median of 3.3% and a range of 2.1-8.7%. After cultured with Gemcitabine for 3 d, the proportion of SP cells increased significantly (3.8% ± 1.9%, 10.7% ± 3.7%, t = 4.616, P = 0.001 < 0.05). ABCB1 and ABCG2 expressed at higher concentrations in SP as compared with non-SP cells (ABCB1: 1.15 ± 0.72, 5.82 ± 1.16, t = 10.839, P = 0.000 < 0.05; ABCG2: 1.16 ± 0.75, 5.48 ± 0.94, t = 11.305, P = 0.000 < 0.05), which may contribute to the efflux of fluorescent staining and drug resistance. CONCLUSION: SP cells with inherently high resistance to chemotherapeutic agents do exist in pancreatic cancers, which may be candidate cancer stem cells contributing to the relapse of the tumor.

Induced pluripotent stem cells for therapy personalization in pediatric patients:Focus on drug-induced adverse events

Adverse drug reactions(ADRs)are major clinical problems,particularly in special populations such as pediatric patients.Indeed,ADRs may be caused by a plethora of different drugs leading,in some cases,to hospitalization,disability or even death.In addition,pediatric patients may respond differently to drugs with respect to adults and may be prone to developing different kinds of ADRs,leading,in some cases,to more severe consequences.To improve the comprehension,and thus the prevention,of ADRs,the set-up of sensitive and personalized assays is urgently needed.Important progress is represented by the possibility of setting up groundbreaking patient-specific assays.This goal has been powerfully achieved using induced pluripotent stem cells(iPSCs).Due to their genetic and physiological species-specific differences and their ability to be differentiated ideally into all tissues of the human body,this model may be accurate in predicting drug toxicity,especially when this toxicity is related to individual genetic differences.This review is an up-to-date summary of the employment of iPSCs as a model to study ADRs,with particular attention to drugs used in the pediatric field.We especially focused on the intestinal,hepatic,pancreatic,renal,cardiac,and neuronal levels,also discussing progress in organoids creation.The latter are three-dimensional in vitro culture systems derived from pluripotent or adult stem cells simulating the architecture and functionality of native organs such as the intestine,liver,pancreas,kidney,heart,and brain.Based on the existing knowledge,these models are powerful and promising tools in multiple clinical applications including toxicity screening,disease modeling,personalized and regenerative medicine.

Neural stem cells isolated from amyloid precursor proteinmutated mice for drug discovery

AIM: To develop an in vitro model based on neural stem cells derived from transgenic animals, to be used in the study of pathological mechanisms of Alzheimer's disease and for testing new molecules.METHODS: Neural stem cells(NSCs) were isolated from the subventricular zone of Wild type(Wt) and Tg2576 mice. Primary and secondary neurosphere generation was studied, analysing population doubling and the cell yield per animal. Secondary neurospheres were dissociated and plated on MCM Gel Cultrex 2D and after 6 d in vitro(DIVs) in mitogen withdrawal conditions,spontaneous differentiation was studied using specific neural markers(MAP2 and TuJ-1 for neurons, GFAP forastroglial cells and CNPase for oligodendrocytes). Gene expression pathways were analysed in secondary neurospheres, using the QIAGEN PCR array for neurogenesis, comparing the Tg2576 derived cell expression with the Wt cells. Proteins encoded by the altered genes were clustered using STRING web software.RESULTS: As revealed by 6E10 positive staining, all Tg2576 derived cells retain the expression of the human transgenic Amyloid Precursor Protein. Tg2576 derived primary neurospheres show a decrease in population doubling. Morphological analysis of differentiated NSCs reveals a decrease in MAP2- and an increase in GFAP-positive cells in Tg2576 derived cells. Analysing the branching of TuJ-1 positive cells, a clear decrease in neurite number and length is observed in Tg2576 cells.The gene expression neurogenesis pathway revealed11 altered genes in Tg2576 NSCs compared to Wt.CONCLUSION: Tg2576 NSCs represent an appropriate AD in vitro model resembling some cellular alterations observed in vivo, both as stem and differentiated cells.

Targeting cancer stem cells in drug discovery: Current state and future perspectives

In recent decades,cancer stem cells(CSCs)have been increasingly identified in many malignancies.CSC-related signaling pathways and their functions provide new strategies for treating cancer.The aberrant activation of related signaling pathways(e.g.,Wnt,Notch,and Hedgehog pathways)has been linked to multiple types of malignant tumors,which makes these pathways attractive targets for cancer therapy.CSCs display many characteristic features,such as self-renewal,differentiation,high tumorigenicity,and drug resistance.Therefore,there is an urgent need to develop new therapeutic strategies to target these pathways to control stem cell replication,survival,and differentiation.Notable crosstalk occurs among different signaling pathways and potentially leads to compensatory escape.Therefore,multitarget inhibitors will be one of the main methods to overcome the drug resistance of CSCs.Many small molecule inhibitors of components of signaling pathways in CSCs have entered clinical trials,and some inhibitors,such as vismodegib,sonidegib,and glasdegib,have been approved.Tumor cells are susceptible to sonidegib and vismodegib resistance due to mutations in the Smo protein.The signal transducers and activators of transcription 3(STAT3)inhibitor BBI608 is being evaluated in a phase III trial for a variety of cancers.Structural derivatives of BBI608 are the main focus of STAT3 inhibitor development,which is another strategy for CSC therapy.In addition to the potential pharmacological inhibitors targeting CSCrelated signaling pathways,other methods of targeting CSCs are available,such as nano-drug delivery systems,mitochondrion targeting,autophagy,hyperthermia,immunotherapy,and CSC microenvironment targeting.In addition,we summarize the latest advances in the clinical development of agents targeting CSC-related signaling pathways and other methods of targeting CSCs.

Mesenchymal stem cells-derived extracellular vesicles as‘natural’drug delivery system for tissue regeneration

Mesenchymal stem cells(MSCs)have abilities to mediate tissue protection through mechanisms of antiapoptosis,anti-oxidative stress and anti-fibrosis as well as tissue regeneration through mechanisms of cell proliferation,differentiation and angiogenesis.These effects by MSCs are mediated by a variety of factors,including growth factors,cytokines and extracellular vesicles(EVs).Among these factors,EVs,containing proteins,mRNA and microRNAs(miRNA),may carry their contents into distant tissues with high stability.Therefore,the treatment with MSC-derived EVs may be promising as‘natural’drug delivery systems(DDS).Especially,the treatment of MSCderived EVs with the manipulation of specific miRNAs expression has been reported to be beneficial under a variety of diseases and tissue injuries.The overexpression of specific miRNAs in the EVs might be through pre-loading method using the gene editing system by plasmid vector or post-loading method to load miRNA mimics into EVs by electroporation or calcium chloride-mediated transfection.Despite current several challenges for clinical use,it should open the next era of regenerative medicine for a variety of diseases.In this article,we highlight the therapeutic potential of MSC-derived EVs as‘natural’DDS and current challenges.

Therapies targeting cancer stem cells: Current trends and future challenges

Traditional therapies against cancer, chemo- and radiotherapy, have multiple limitations that lead to treatment failure and cancer recurrence. These limitations are related to systemic and local toxicity, while treatment failure and cancer relapse are due to drug resistance and self-renewal, properties of a small population of tumor cells called cancer stem cells(CSCs). These cells are involved in cancer initiation, maintenance, metastasis and recurrence. Therefore, in order to develop efficient treatments that can induce a longlasting clinical response preventing tumor relapse it is important to develop drugs that can specifically target and eliminate CSCs. Recent identification of surface markers and understanding of molecular feature associated with CSC phenotype helped with the design of effective treatments. In this review we discuss targeting surface biomarkers, signaling pathways that regulate CSCs self-renewal and differentiation, drug-efflux pumps involved in apoptosis resistance, microenvironmental signals that sustain CSCs growth, manipulation of mi RNA expression, and induction of CSCs apoptosis and differentiation, with specific aim to hamper CSCs regeneration and cancer relapse. Some of these agents are under evaluation in preclinical and clinical studies, most of them for using in combination with traditional therapies. The combined therapy using conventional anticancer drugs with CSCs-targeting agents, may offer a promising strategy for management and eradication of different types of cancers.

Gastric cancer stem cells in gastric carcinogenesis,progression,prevention and treatment

In recent decades,the study of the mechanism of tumorigenesis has brought much progress to cancer treatment.However,cancer stem cell(CSC)theory has changed previous views of tumors,and has provided a new method for treatment of cancer.The discovery of CSCs and their characteristics have contributed to understanding the molecular mechanism of tumor genesis and development,resulting in a new effective strategy for cancer treatment.Gastric CSCs(GCSCs)are the basis for the onset of gastric cancer.They may be derived from gastric stem cells in gastric tissues,or bone marrow mesenchymal stem cells.As with other stem cells,GCSCs highly express drug-resistance genes such as aldehyde dehydrogenase and multidrug resistance,which are resistant to chemotherapy and thus form the basis of drug resistance.Many specific molecular markers such as CD44 and CD133 have been used for identification and isolation of GCSCs,diagnosis and grading of gastric cancer,and research on GCSC-targeted therapy for gastric cancer.Therefore,discussion of the recent development and advancements in GCSCs will be helpful for providing novel insight into gastric cancer treatment.

Circulating cancer stem cells:the importance to select

It has been demonstrated that even localized tumors withottt chnically apparent metastasis give rise to circulating tumor cells （CTCs）. A growing number of technically diverse platforms are being developed for detecting/isolating CTCs in the circulating blood. Despite the technical challenges of isolating rare CTCs from blood, recent studies have already shown the predictive value of CTCs enumeration. Thus, it is becoming increasingly accepted that CTC numbers are linked to patients＇ outcome and may also be used to monitor treatment response and disease relapse, respectively. Further CTCs provide a non-invasive source for tumor material, ＇liquid biopsy＇, which is particularly important for patients, where no biopsy material can be obtained or where serial biopsies of the tumor, e.g., following treatment, are practically impossible. On the other hand the molecular and biological characterization of CTCs has still remained at a rather experimental stage. Future studies are necessary to define CTC heterogeneity to establish the crucial role of circulating cancer stem cells for driving metastasis, which represent a distinct subpopulation of CTCs that bear metastasis-initiating capabilities based on their sternness properties and invasiveness and thus are critical for the patients＇ clinical outcome. As compared to non-tumorigenic/metastatic bulk CTCs, circulating cancer stem cells may not only be capable of evading from the primary tumor, but also escape from immune surveillance, survive in the circulating blood and subsequently form metastases in distant organs. Thus, circulating cancer stem cells represent a subset of exclusively tumorigenic cancer stem cells characterized by their invasive characteristics and are potential therapeutic targets for preventing disease progression. To date, only a few original reports and reviews have been published focusing on circulating cancer stem cells. This review discusses the potential importance of isolating and characterizing these circulating cancer stem cells, but also highlights current technological limitations.

Human embryonic stem cell-derived mesenchymal stem cells improved premature ovarian failure

BACKGROUND Premature ovarian failure(POF)affects many adult women less than 40 years of age and leads to infertility.According to previous reports,various tissue-specific stem cells can restore ovarian function and folliculogenesis in mice with chemotherapy-induced POF.Human embryonic stem cells(ES)provide an alternative source for mesenchymal stem cells(MSCs)because of their similarities in phenotype and immunomodulatory and anti-inflammatory characteristics.Embryonic stem cell-derived mesenchymal stem cells(ES-MSCs)are attractive candidates for regenerative medicine because of their high proliferation and lack of barriers for harvesting tissue-specific MSCs.However,possible therapeutic effects and underlying mechanisms of transplanted ES-MSCs on cyclophosphamide and busulfan-induced mouse ovarian damage have not been evaluated.AIM To evaluate ES-MSCs vs bone marrow-derived mesenchymal stem cells(BMMSCs)in restoring ovarian function in a mouse model of chemotherapy-induced premature ovarian failure.METHODS Female mice received intraperitoneal injections of different doses of cyclophosphamide and busulfan to induce POF.Either human ES-MSCs or BMMSCs were transplanted into these mice.Ten days after the mice were injected with cyclophosphamide and busulfan and 4 wk after transplantation of the ESMSCs and/or BM-MSCs,we evaluated body weight,estrous cyclicity,folliclestimulating hormone and estradiol hormone concentrations and follicle count were used to evaluate the POF model and cell transplantation.Moreover,terminal deoxynucleotidyl transferase mediated 2-deoxyuridine 5-triphosphate nick end labeling,real-time PCR,Western blot analysis and immunohistochemistry and mating was used to evaluate cell transplantation.Enzyme-linked immunosorbent assay was used to analyze vascular endothelial growth factor,insulin-like growth factor 2 and hepatocyte growth factor levels in ES-MSC condition medium in order to investigate the mechanisms that underlie their function.RESULTS The human ES-MSCs significantly restored hormone secretion,survival rate and reproductive function in POF mice,which was similar to the results obtained with BM-MSCs.Gene expression analysis and the terminal deoxynucleotidyl transferase mediated 2-deoxyuridine 5-triphosphate nick end labeling assay results indicated that the ES-MSCs and/or BM-MSCs reduced apoptosis in the follicles.Notably,the transplanted mice generated new offspring.The results of different analyses showed increases in antiapoptotic and trophic proteins and genes.CONCLUSION These results suggested that transplantation of human ES-MSCs were similar to BM-MSCs in that they could restore the structure of the injured ovarian tissue and its function in chemotherapy-induced damaged POF mice and rescue fertility.The possible mechanisms of human ES-MSC were related to promotion of follicular development,ovarian secretion,fertility via a paracrine effect and ovarian cell survival.

Thinking outside the liver: Induced pluripotent stem cells for hepatic applications

The discovery of induced pluripotent stem cells (iPSCs) unraveled a mystery in stem cell research, after identification of four re-programming factors for generating pluripotent stem cells without the need of embryos. This breakthrough in generating iPSCs from somatic cells has overcome the ethical issues and immune rejection involved in the use of human embryonic stem cells. Hence, iPSCs form a great potential source for developing disease models, drug toxicity screening and cell-based therapies. These cells have the potential to differentiate into desired cell types, including hepatocytes, under in vitro as well as under in vivo conditions given the proper microenvironment. iPSC-derived hepatocytes could be useful as an unlimited source, which can be utilized in disease modeling, drug toxicity testing and producing autologous cell therapies that would avoid immune rejection and enable correction of gene defects prior to cell transplantation. In this review, we discuss the induction methods, role of reprogramming factors, and characterization of iPSCs, along with hepatocyte differentiation from iPSCs and potential applications. Further, we discuss the location and detection of liver stem cells and their role in liver regeneration. Although tumor formation and genetic mutations are a cause of concern, iPSCs still form a promising source for clinical applications.

Emerging role of microRNAs in cancer stem cells:Implications in cancer therapy

A small subset of cancer cells that act as tumor initiating cells or cancer stem cells(CSCs) maintain self-renewal and growth promoting capabilities of cancer and are responsible for drug/treatment resistance,tumor recurrence and metastasis. Due to their potential clinical importance,many researchers have put their efforts over decades to unravel the molecular mechanisms that regulate CSCs functions. Micro RNAs(mi RNAs) which are 21-23 nucleotide long,endogenous noncoding RNAs,regulate gene expression through gene silencing at post-transcriptional level by binding to the 3'-untranslated regions or the open reading frames of target genes,thereby result in target mR NA degradation or its translational repression and serve important role in several cellular,physiological and developmental processes. Aberrant mi RNAs expression and their implication in CSCs regulation by controlling asymmetric cell division,drug/treatment resistance and metastasis make mi RNAs a tool of great therapeutic potential against cancer. Recent advancements on the biological complexities of CSCs,modulation in CSCs properties by mi RNA network and development of mi RNA based treatment strategies specifically targeting the CSCs as an attractive therapeutic targets for clinical application are being critically analysed.

STAT3 mediates resistance of CD44^+CD24^(-/low) breast cancer stem cells to tamoxifen in vitro

We sought to determine whether STAT3 mediated tamoxifen resistance of breast cancer stem cells in vitro.The capacities for mammosphere formation and STAT3 expression of CD44＋CD24-/low MCF-7 and MCF-7 were observed.The CD44＋CD24-/low subpopulation ratio and its sensitivity to adriamycin were analyzed in MCF-7 and TAM resistant（TAM-R） cells.Cell cycle,apoptosis,STAT3 and phospho-STAT3 changes were observed af-ter treatment with tamoxifen.Small interference RNA-mediated knockdown of STAT3 in TAM-R cells was also performed.CD44＋CD24-/low MCF-7 showed higher capacities for mammosphere formation and STAT3 expression than total MCF-7.The CD44＋CD24-/low subpopulation was also upregulated in TAM-R cells with less sensitivity to adriamycin than MCF-7.Cell cycle changes,anti-apoptotic effects and STAT3 changes were also found.Mean-while,the knock-down of STAT3 in TAM-R resulted in an increase in sensitivity to tamoxifen.It is concluded that STAT3 plays an essential role in breast cancer stem cells,which correlated with tamoxifen resistance.

Therapeutic opportunities and challenges of induced pluripotent stem cells-derived motor neurons for treatment of amyotrophic lateral sclerosis and motor neuron disease

Amyotrophic lateral sclerosis（ALS） and motor neuron diseases（MNDs） are progressive neurodegenerative diseases that affect nerve cells in the brain affecting upper and lower motor neurons（UMNs/LMNs）, brain stem and spinal cord. The clinical phenotype is characterized by loss of motor neurons（MNs）, muscular weakness and atrophy eventually leading to paralysis and death due to respiratory failure within 3–5 years after disease onset. No effective treatment or cure is currently available that halts or reverses ALS and MND except FDA approved drug riluzole that only modestly slows the progression of ALS in some patients. Recent advances in human derived induced pluripotent stem cells have made it possible for the first time to obtain substantial amounts of human cells to recapitulate in vitro “disease in dish” and test some of the underlying pathogenetic mechanisms involved in ALS and MNDs. In this review, I discussed the opportunities and challenges of induced pluropotent stem cells-derived motor neurons for treatment of ALS and MND patients with special emphasis on their implications in finding a cure for ALS and MNDs.