Study on mechanism of interfering with LncRNA expressing to reduce paclitaxel resistance in non-small cell lung cancer cells / 中国药房

OBJECTIVE To study the mechanism of interfering with long non-coding RNA nicotinamide nucleotide transhydrogenase-antisense RNA1 （LncRNA NNT-AS1） expressing to reduce paclitaxel （TAX） resistance in non-small cell lung cancer （NSCLC） cells. METHODS NSCLC TAX-resistant cell line （A549/TAX） was constructed， and the expressions of LncRNA NNT-AS1 in normal， parental， and drug-resistant cells were observed. The targeting relationship of microRNA-582-5p （miR-582- 5p） with LncRNA NNT-AS1 and high mobility group box2 （HMGB2） was verified. A549/TAX cells were cultured in vitro to observe the effects of interfering with LncRNA NNT-AS1 alone or interfering with LncRNA NNT-AS1 and miR-582-5p on the expressions of LncRNA NNT-AS1 and miR-582-5p， the mRNA and protein expressions of HMGB2， cell viability， clone formation and apoptosis. The effects of interfering with LncRNA NNT-AS1 on tumor growth and the expression of miR-582-5p and the mRNA and protein expressions of HMGB2 in tumor tissue were observed in nude mice. RESULTS Compared with normal cells， LncRNA NNT-AS1 was highly expressed in parental and drug-resistant cells （P＜0.05）， showing an increasing trend. It was validated that miR-582-5p had a targeting relationship with LncRNA NNT-AS1 and HMGB2. After interfering with the expression of LncRNA NNT-AS1， the expression of LncRNA NNT-AS1 and the mRNA and protein expressions of HMGB2， cell viability and the number of cloned cells in A549/TAX cell， decreased significantly， while the expression of miR-582-5p and the apoptotic rate increased significantly （P＜0.05）； simultaneously interfering with the expression of miR-582-5p could reverse above changes （P＜ 0.05）. Interfering with the expression of LncRNA NNT-AS1 in tumor cell could significantly reduce tumor volume and tumor weight of nude mice bearing tumors； at the same time， the expression of miR-582-5p was up-regulated significantly and the mRNA and protein expressions of HMGB2 were down-regulated significantly （P＜0.05）. CONCLUSIONS Interfering with the expression of LncRNA NNT-AS1 may alleviate TAX chemotherapy resistance in NSCLC through targeted up-regulation of miR-582-5p and down-regulation of HMGB2.

Advance in the chemotherapy resistance of retinoblastoma / 国际眼科杂志(Guoji Yanke Zazhi)

Retinoblastoma(RB)is the most common intraocular malignant tumor of children. Chemotherapy is a preferred method in RB treatment, which includes intravenous chemotherapy, intra-arterial chemotherapy and intravitreal chemotherapy. However, the occurrence of chemotherapy resistance often leads to the failure of eye-preserving treatment in RB patients. Therefore, exploring the mechanism of the occurrence of chemotherapy resistance and searching for new strategies and combined medicines for RB treatment are of great clinical significance. This article reviews that RB cells obtain chemotherapy resistance through ATP binding cassette protein(ABC transporter), non-coding RNA, epigenetics modification, autophagy, epithelial mesenchymal transformation, extracellular matrix changes and other ways, and the potential therapeutic targets for chemotherapy resistance are also summarized, in the hope of providing some references for further research on chemotherapy resistance of RB.

Roles of lncRNA in the diagnosis and prognosis of triple-negative breast cancer / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Breast cancer is a malignant tumor that seriously endangers women's lives. The prognosis of breast cancer patients differs among molecular types. Compared with other subtypes, triple-negative breast cancer (TNBC) has been a research hotspot in recent years because of its high degree of malignancy, strong invasiveness, rapid progression, easy of recurrence, distant metastasis, poor prognosis, and high mortality. Many studies have found that long non-coding RNA (lncRNA) plays an important role in the occurrence, proliferation, migration, recurrence, chemotherapy resistance, and other characteristics of TNBC. Some lncRNAs are expected to become biomarkers in the diagnosis and prognosis of TNBC, and even new targets for its treatment. Based on a PubMed literature search, this review summarizes the progress in research on lncRNAs in TNBC and discusses their roles in TNBC diagnosis, prognosis, and chemotherapy with the hope of providing help for future research.

Discussion on the Formation and Prevention Strategies of Chemotherapy Resistance of Malignant Tumor Based on “Yin Fire” Theory / 中医杂志

Chemotherapy is currently the main clinical treatment method for malignant tumors， and chemotherapy resistance is the main factor leading to chemotherapy failure and malignant tumor recurrence and metastasis. The cha-racteristics of malignant tumors formation were regarded as similar to the “Yin Fire” theory， manifested that deficiency of original qi as the foundation of malignant tumors， imbalance of original qi and yin fire as the internal cause of malignant tumor progression， and the internal environment of phlegm-blood stasis-toxicity-deficiency caused by yin fire promoted the formation of chemoresistance. In the treatment of chemoresistance of malignant tumors， traditional Chinese medicine should focus on treating disease before its onset by tonifying the spleen and strengthening the middle， nou-rishing the original qi， and reinforcing healthy qi and anti-cancer； during the treatment， the clinicians should regulate the qi and detoxify to clear yin fire， and improve the internal environment. Summarily， the strategies were adjusting the balance of internal environment of original qi and yin fire， and conducting a comprehensive treatment during the whole process， to provide new ideas for the treatment of chemoresistance of malignant tumors with traditional Chinese medicine.

Research progress of circular RNA in drug resistance of liver cancer / 中国药理学通报

Circular RNAs are novel non-coding RNAs with multiple biological functions, which can participate in biological processes such as the occurrence, development, invasion, and metastasis of liver cancer, as well as drug resistance of liver cancer. This article reviews the roles and mechanisms of circR-NAs in chemotherapy resistance, targeted therapy resistance and immunotherapy resistance in liver cancer, in order to provide new ideas for solving liver cancer resistance.

Mechanism of Chemotherapy Resistance of Hepatocellular Carcinoma and Intervention with Chinese Medicine： A Review / 中国实验方剂学杂志

Multidrug resistance （MDR） has been a main culprit behind the failure of chemotherapy in patients with malignant tumors and a major obstacle to improving the life quality and prolonging the survival of patients. Hepatocellular carcinoma cells， the innate drug-resistant cells， are generally insensitive to radiotherapy and chemotherapy. Moreover， as the early symptoms of hepatocellular carcinoma are atypical， most patients are diagnosed at the advanced stage， with short survival period and high recurrence rate. Thus， the sensitivity to chemotherapy drugs is decreased. This explains how MDR becomes one of the important reasons for the failure of primary hepatocellular carcinoma （PHC） treatment. Therefore， it is an urgent task to search for safe and effective chemosensitizers with little adverse effect in the research on the drug resistance of hepatocellular carcinoma. As Chinese medicine has been widely applied in the treatment of tumors， the mechanisms of compound Chinese medicine prescriptions， Chinese medicine injections， and single Chinese medicinal in reversing chemotherapy resistance in liver cancer have attracted the interest of scholars. According to previous reports， the mechanisms can be summarized as increasing intracellular drug concentration， influencing changes in enzyme activity， inducing apoptosis， reversing abnormalities in cellular signaling pathways， and regulating the tumor microenvironment. Traditional Chinese medicine reduces the chemotherapy resistance of hepatocellular carcinoma cells through multiple targets and multiple pathways， thereby improving the chemotherapy sensitivity of the cancer cells and enhancing the toxicity of chemotherapeutic drugs to hepatocellular carcinoma cells. Therefore， exploring the mechanism of MDR of hepatocellular carcinoma from the perspective of traditional Chinese medicine is important for reversing the MDR and is of great reference value for clinical treatment of hepatocellular carcinoma. However， there are few experimental types and adverse effects available. Thus， the multi-mechanism and multi-target experiments and clinical research should be carried out in the future.

Mechanism of Chinese Herbal Monomers Against Cisplatin-induced Resistance of Ovarian Cancer： A Review / 中国实验方剂学杂志

Because the early symptoms of ovarian cancer are not typical and there is a lack of effective screening methods， most patients are diagnosed at an advanced stage， which seriously endangers the health of modern women. Platinum-based chemotherapy after tumor reduction is the first choice for patients with advanced and recurrent ovarian cancer， but almost all patients with recurrent ovarian cancer will eventually develop platinum resistance. Therefore， the search for natural， safe， and effective chemotherapeutic sensitizers has become an urgent and important topic in the study of ovarian cancer. With the increasingly extensive application of traditional Chinese medicine （TCM） in the treatment of cancer， the research on Chinese herbal monomers is also deepening， and the mechanisms of Chinese herbal monomers in intervening in cisplatin （DDP）-induced resistance of ovarian cancer is becoming increasingly clearer. Based on the research status of Chinese herbal monomers available in many Chinese and English databases， it was found that Chinese herbal monomers were involved in the reversal of DDP-induced resistance of ovarian cancer via many routes， mainly through increasing the intracellular drug concentration， reversing the blocked apoptosis， correcting the abnormal intracellular signaling pathway， enhancing DNA damage and inhibiting DNA repair， regulating intracellular autophagy， and suppressing epithelial mesenchymal transition （EMT）. Chinese herbal monomers weaken the resistance of ovarian cancer to DDP from multiple targets and enhance the toxicity of DDP to ovarian cancer cells in vitro and transplanted tumors in vivo. Therefore， Chinese herbal monomers are expected to become natural sensitizers for ovarian cancer chemotherapy with DDP. However， the current studies on Chinese herbal monomers are still confined to the single experimental type， and their action mechanisms and toxic and side effects remain to be further clarified. The application of Chinese herbal monomers for sensitizing DDP chemotherapy still needs to be verified by multi-target， multi-level experimental studies and large-scale clinical studies in the future.

Recent progress of novel circular RNA regulating chemotherapy resistance in glioma / 中国药房

Glioma is a malignant tumor with extremely high rates of recurrence. Clinically ，with the prolongation of the use of chemotherapy drugs ，the drug resistance of glioma cells to chemotherapy drugs is also increasing ，which eventually leads to poor prognosis and shortens overall survival time of patients. It is well known that the development of drug resistance involves multiple mechanisms，including drug transport metabolism ，apoptosis，DNA damage repair ，autophagy，variation of cancer stem cells and epithelial mesenchymal transition. Abnormal expression of circular RNA （circRNA），a novel RNA molecule with unique stability and tissue specificity ，has been shown by more and more evidence to play a crucial regulatory role in the development of drug resistance in glioma. This paper systematically reviews the mechanism of multiple drug resistance in glioma ，and focuses on the role and molecular mechanism of circRNA regulating temozolomide-resistance in glioma. At the same time ，the potential function of circRNA as a new therapeutic target is prospected ，in order to provide an objective theoretical basis for the development of new therapeutic methods.

Exosomal Circular RNAs Mediates Chemotherapy Resistance in Tumors / 中国生物化学与分子生物学报

As an important member of the non-coding RNA family, circRNA is a kind of single-stranded RNA with a covalently closed loop structure without a polyadenylated acid tail and 5'-3' end, showing high stability, abundance and conservation across species characteristics. Recent studies have shown that circRNA plays an important role in many biological processes, including chemotherapy resistance and malignant progression. Exosomes are small extracellular phospholipid bilayer vesicles with a diameter of30-150 nm that are secreted by living cells. They can be used as carriers to encapsulate and transfer functional molecules. Exosomes are important mediators of communication between tumor cells and stromal cells. They can play a role in the transmission of chemoresistance by transferring circRNA. Aschemotherapy resistance is still a huge obstacle to the prognosis of cancer, the research of exosomalcircRNA-mediated tumor chemotherapy resistance is at the forefront of academic research, which is a blueocean with important significance. In this paper, we summarized the latest research progress in the aspects of exosome delivery of circRNA, the mechanism of exosome sorting non-coding RNA cargo, circRNA-mediated tumor chemotherapy resistance, exosome delivery of circRNA-mediated tumor chemotherapy resistance and its potential clinical application, which may provide a reference for the research of tumor chemotherapy resistance.

Effect of LINC00672 on sensitivity of breast cancer to tamoxifen and its related mechanisms / 中华内分泌外科杂志

Objective:To investigate the effect of long non-coding RNA (LncRNA) LINC00672 on sensitivity of breast cancer to tamoxifen and related mechanisms.Methods:Human breast cancer MCF-7 cells was treated in vitro to establish tamoxifen resistance (resistance group) and corresponding parental cell line (parent group) . The interfered LINC00672 and control cell line were constructed by Crisper-cas9 in resistant cells. (Interference 1 group, interference 2 group and control group) . The expression of LINC00672, Akt and HER2 mRNA was determined by real-time quantitative PCR. The expression levels of total Akt (Akt-pan) , phosphorylation of Akt (p-Akt) and HER2 were detected by Western blot.CCK-8 assay was used to detect cell resistance to tamoxifen.Results:The expressions of LINC00672, Akt and HER2 mRNA in the parental group were (1.000±0.086) , (1.000±0.254) and (1.000±0.208) , and the TAM IC 50 was (1.417±0.153) μmol/L. The expressions of LINC00672, Akt and HER2 mRNA in the resistance group were (4.286±0.593) , (4.175±0.274) and (2.519±0.389) , and the TAM IC 50 was (12.029±1.016) μmol/L. The expressions of LINC00672, Akt and HER2 mRNA in the control group were (1.000±0.093) , (1.000±0.090) and (1.000±0.097) , and the TAM IC 50 was (10.58±0.639) μmol/L. The expressions of LINC00672, Akt and HER2 mRNA in the interference group 1 were (0.331±0.023) , (0.892±0.044) and (0.458±0.077) , and the TAM IC 50 was (6.250±0.836) μmol/L. The expressions of LINC00672, Akt and HER2 mRNA in the interference group 2 were (0.304±0.016) , (0.919±0.050) and (0.416±0.080) , and the TAM IC 50 was (4.764±0.553) μmol/L. As compared with the parental group, the expressions of LINC00672, Akt and HER2 mRNA were significantly up-regulated ( P<0.01) in resistance group, the protein levels of Akt-pan, p-Akt and HER2 was up-regulated. The IC 50 value of tamoxifen was significantly increased in resistance group ( P<0.01) . As compared with the control group, the expression levels of LINC00672 and HER2 mRNA were significantly decreased in the interference group 1 and the interference group 2 ( P<0.01) , the levels of Akt was not significantly changed ( P>0.05) . The protein levels of p-Akt and HER2 were significantly decreased but there was no significant change in the expression of Akt-pan. The IC50 value of tamoxifen was significantly decreased ( P<0.01) . Conclusion:LINC00672 may be involved in the formation of tamoxifen resistance in breast cancer cells, and its underlying mechanism is related to the promotion of HER2/p-Akt pathway.

Role of Tumor Associated Macrophages in Chemotherapy Resistance and Intervention with Traditional Chinese Medicine： A Review / 中国实验方剂学杂志

The tumor incidence goes up with every passing year. Chemotherapy， as one of the main treatment methods， is faced with a major challenge of drug resistance in clinical practice. Tumor-associated macrophages （TAMs） are the key factors inducing chemotherapy resistance of tumors. TAMs are inflammatory cells with the largest number in the tumor microenvironment， which are widely distributed in such epithelial tissues as large intestine and stomach in the immune environment and closely associated with multiple common cancers like breast cancer and colorectal cancer. TAMs can be divided into two phenotypes， with M2-polarized TAMs into the tumor-promoting phenotype that affects the oncogenesis and progression and promotes drug resistance via immune escape， angiogenesis and other ways. At the same time， the frequently utilized chemotherapeutic agents will increase the recruitment of TAMs and trigger the secretion of cytokines， leading to the excessive polarization of macrophages to M2 type， followed by tumor drug resistance. The molecular mechanism of chemotherapy resistance is complex， which is becoming an urgent problem in the field of chemotherapy. Traditional Chinese medicine （TCM） has exhibited unique advantages in resisting tumor drug resistance. It has been proved efficient and safe in improving tumor microenvironment and regulating TAMs by acting on multiple targets via multiple ways， thus adjusting tumor progression and improving drug resistance. Based on related articles published in recent years， this paper reviewed the drug resistance-promoting effect of TAMs via regulating the immune microenvironment and interacting with tumor stem cells and the driving effect of chemotherapeutic agents on drug resistance to figure out the role of TAMs in chemotherapy resistance. Besides， it summarized the mechanisms of TCM in regulating related cytokines， proteins， activity， and the polarization direction of TAMs to expound the effective components of TCM in the intervention of drug resistance. The aim of this paper was to provide reference for further research on the biological mechanism of chemotherapy resistance and its targeted intervention with TCM.

The role of nuclear receptor transcription factor NR2F6 in tumor / 生物工程学报

Nuclear receptor subfamily 2, group F, member 6 (NR2F6) is a member of orphan nuclear receptors, which is expressed in major tissues and organs of the human body, and plays an important role in the regulation of various biological functions and gene expressions. Recent studies have shown that the expression of NR2F6 was up-regulated in a variety of malignant tumors and showed significant correlations with cancer progression. These findings triggered the widespread interest in understanding the relationship between NR2F6 and cancer development and progression. In addition, the latest studies have underscored that NR2F6 was involved in enhancing antitumor immune responses that could serve as a potential target for immune regulation. This review summarizes the biological functions of NR2F6 and its role in tumors, with the aim to provide new insights into effective cancer therapies.

Effect of lncRNA FAL1 on Chemotherapy Resistance of Ovarian Cancer Cells by Regulating MAPK Pathway and Related Mechanism / 肿瘤防治研究

Objective To observe the expression difference of lncRNA FAL1 in ovarian cancer cells and their drug-resistant cell lines, and to explore the effect and mechanism of lncRNA FAL1 down-regulation on cell chemotherapy resistance. Methods The expression levels of fal1 gene in SKOV3 and COC1 cells and their drug-resistant cell lines were detected by qRT-PCR. fal1 siRNA was transfected to downregulate fal1 gene expression. MTT was used to detect cell proliferation. Transwell method was used to detect cell invasion ability. Plate clone formation test was used to detect cell clone ability, and Western blot was used to detect MDR-1, mpr-1, ABCG2 and phosphorylation levels of p38 MAPK, ERK1/2 and JNK. SKOV3/DDP and COC1/DDP cells transfected with FAL1-siRNA were injected subcutaneously into BALB/c nude mice. The volume and mass of subcutaneous transplanted tumors were measured. Results Compared with SKOV3 and COC1 cells, SKOV3/DDP and COC1/DDP cells were less sensitive to DDP, and the expression levels of FAL1 gene increased (P < 0.01). After transfection with FAL1-siRNA, the sensitivity of SKOV3/DDP and COC1/DDP cells to DDP increased (P < 0.01), and the invasion (P < 0.05) and cloning ability (P < 0.01) decreased. The expression levels of MDR-1, MPR-1, ABCG2 (P < 0.01) and the phosphorylation levels of p38 MAPK, ERK1/2 and JNK (P < 0.05) decreased. The volume and mass of subcutaneous transplanted tumors were significantly reduced (P < 0.01). Conclusion Down-regulation of lncRNA FAL1 could significantly reduce the chemotherapy resistance of cisplatin-resistant ovarian cancer cell lines and inhibit the proliferation of drug-resistant cells in vivo. Its mechanism is related to inhibiting the activation of MAPK signaling pathway.

Reviews on TCM in Reversing Chemotherapy Resistance of Osteosarcoma from ABC Transmembrane Protein / 肿瘤防治研究

Osteosarcoma (OS) is the most common primary malignant bone tumor in clinic. It has high mortality and disability rate. Effective neoadjuvant chemotherapy combined with limb salvage surgery can improve the 5-year survival rate of OS patients. Drug resistance or low sensitivity of tumor cells is the most common cause of postoperative local recurrence and metastasis. Therefore, the sensitivity of OS cells to chemotherapy drugs is of great value to the prognosis of the patients. In recent years, traditional Chinese medicine has been widely used because of high efficiency and low toxicity. A large number of studies have confirmed that part of traditional Chinese medicine can reverse the chemotherapy resistance of OS cells by regulating the ABC transmembrane transport protein system. This article gives an overview of its related mechanisms and latest developments.

Regulatory effect and mechanism of miR-9-5p on malignant biological behaviors of breast cancer / 中国肿瘤生物治疗杂志

@#[Abstract] Objective: To explore the role of miR-9-5p in the biological behaviors of breast cancer cells and its possible regulatory mechanism. Methods: online OncomiR database was used to analyze the differential expression of miR-9-5p in breast cancer tissues and normal breast tissues. qPCR was used to detect the miR-9-5p expression in breast cancer cell lines and normal breast cells. Based on target gene prediction software TargetScan, ONECUT2 (one cut homeobox 2) was predicted to be the target gene of miR-9-5p. Dual luciferase reporter system was used to validate the relationship between miR-9-5p and its promising target gene ONECUT2. MDA-231 cells were transfected with miR-9-5p mimic, ONECUT2 siRNAs as well as the corresponding control sequences. The protein and mRNA levels of stemness-associated gene NOTCH1, NANOG and SOX9 (SRY (sex-determing region of Y chromosome) -Box transcription Factor 9) were detected by WB and qPCR. The effect of transfection on proliferation, apoptosis and chemo-resistance of cells was detected by BrdU method, Annexin Ⅴ method and MTS Assay, respectively. The ALDEFLUOR experiment was used to detect the effects of miR-9-5p and its target gene ONECUT2 on tumor stemness. NSG mouse breast cancer chemotherapy model was established, and the in vivo experiments further verified the effect of ONECUT2 on tumor malignant biological behaviors, such as cell stemness and chemo-resistance. Results: miR-9-5p was highly expressed in breast cancer tissues (P=0.007) and breast cancer MDA-231 cell line (P=0.0005), and was positively correlated with the poor prognosis of breast cancer patients (P=0.0016). Compared to control group, miR-9-5p could target and negatively regulate ONECUT2 expression, further increase ALDH+ cell population (P=0.0006), as well as increase the expressions of stemness-associated genes NOTCH1, NANOG and SOX9. Besides, miR-9-5p increased the anti-apoptosis ability (P=0.0003) and chemo-resistance of MDA-231 cells; however, miR-9-5p/ONECUT2 exerted no significant effect on the proliferation ability of MDA-231 cells (P>0.05). Compared with the control group, the volume of xenografts in mice of MDA-231/ONECUT2 group after DTX chemotherapy was significantly lower than that in the control group (P<0.05), and the protein expressions of NOTCH1, SOX9 and the mRNA expression of ABC transporter in the transplanted tumor tissues were significantly reduced (P<0.05 or P<0.01). Conclusions: The highly expressed miR-9-5p in breast cancer induces tumor stemness and anti-apoptotic ability by targeting ONECUT2 and enhances its resistance to chemotherapy.

Transformation of malignant biological behaviors and PD-L1 expression in esophageal squamous cell carcinomaYES-2 cell induced by CDDPresistance / 中国肿瘤生物治疗杂志

@#[Abstract] Objective: To investigate the changes in malignant biological behaviors and expression of programmed cell death-ligand 1 (PD-L1) in esophageal squamous cell carcinoma (ESCC) YES-2 cell line after cis-dichlorodiammine platinum (CDDP) induction (YES-2/CDDP-R). Methods: YES-2 cells were treated with CDDP from low concentration to high concentration (0.25-2.0 μg/ml) with intermittent impact (15-25 days per concentration) to establish ESCC CDDP-resistant cell line YES-2/CDDP-R. The morphological change of YES-2/CDDP-R cells was observed under the inverted microscope. Methyl thiazolyl tetrazolium (MTT) was used to detect cell sensitivity to CDDP. Wound healing assay was used to detect cell migration ability. qPCR and Western blotting were used to detect mRNA and protein expressions of PD-L1. Results: After CDDP gradien ttreatment for9 months,YES-2/CDDP-R cells were successfully established. The morphology of the YES-2/CDDP-R cells showed uneven size, intracellular vacuoles and significantly increased black particles along with the appearance of huge cells. The IC50 of CDDP for YES-2/CDDP-R cells was significantly higher than that for parental cells, indicating decreased sensitivity to CDDP (P<0.05). Compared to theYES-2 cells, the proliferation and migration of YES-2/CDDP-R cells were significantly increased (P<0.05 or P<0.01), and the mRNA and protein expressions of PD-L1 were significantly up-regulated (all P<0.001). Conclusion: YES-2 cells with CDDP resistance (YES-2/CDDP-R) were successfully established. The sensitivity of YES-2/CDDP-R cells to CDDP was significantly reduced while the abilities of cell proliferation and migration were enhanced. The up-regulation of PD-L1 in YES-2/CDDP-R cells suggests that CDDP-resistance could promote immune escape by inducing PD-L1 up-regulation.

Application of single cell sequencing in breast cancer research / 中华内分泌外科杂志

Single cell sequencing developed in recent years,which studies genome and transcriptome at single cell level,is more suitable for solving problems on minor special sample studies,heterogenous population analysis and finding concurrent or mutually exclusive genomic events,compared to bulk sequencing.For breast cancer,which is highly heterogeneous,bulk sequencing data is not enough for solving many clinical problems,and single cell sequencing precisely plays an important role in it.This review,focusing on a minor special cell population in breast cancer (such as cancer stem cells,circulating tumor cells,et al),tumor heterogeneity and clonal evolution,and chemotherapy resistance,summarized application of single cell sequencing in breast cancer research in recent years,and discussed the future research directions.

Mechanism of Aurora-A to promote chemoresistance in nasopharyngeal carcinoma / 中国耳鼻咽喉头颈外科

OBJECTIVE To explore the mechanism of Aurora kinase A (Aurora-A) promoting cancer cell chemotherapy resistance in nasopharyngeal carcinoma. METHODS The expression of Aurora-A in nasopharyngeal carcinoma tissues and adjacent tissues were detected by Western bolt and Q-PCR. The highexpressing Aurora A cell line CNE2 was used to detected the cell apoptosis and the expression of key pathway marker protein after Aurora-A inhibitor VX680 and cisplatin treatment by using Flow cytometry and WB. RESULTS The expression of Aurora-A in nasopharyngeal carcinoma tissues was significantly higher than that in adjacent tissues. Comparing to normal nasopharyngeal cells NP69, Aurora-A was significantly highly expressed in all of nasopharyngeal carcinoma cells and was highest in CNE2. Inhibiton of Aurora-A increased the cell apoptosis and the expression of p-AKT, p21 and Cleaved-Caspase-3 after using cisplatin or the Aurora-A inhibitor VX680 treatment. CONCLUSION The results shown that Aurora-A confer chemoresistance to cisplatin treatment through p-AKT/p21/Cleaved-Caspase-3 pathway.

Hypoxia increases chemotherapy resistance in nasopharyngeal carcinoma via inducing CDK6 deSUMOylation / 中华耳鼻咽喉头颈外科杂志

Objective@#To understand the mechanism of chemotherapy resistance in nasopharyngeal carcinoma under hypoxic conditions through the perspective of protein SUMOylation modification.@*Methods@#Cobalt chloride (CoCl2) was used to establish the hypoxic model of human nasopharyngeal carcinoma CNE1 cells. Then, the cell cycle was detected by flow cytometry, and the expression level of small ubiquitin-related modifier(SUMO) and cyclin-dependent kinase 6 (CDK6) proteins were detected by western blotting. MTT assay was used to determine the median lethal dose (IC50) of cancer cells against cisplatin, and enzyme-linked immunosorbent assay (ELISA) was used to determine lactate dehydrogenase (LDH) level.@*Results@#The cell cycle of CNE1 induced by hypoxia was arrested in G0/G1 phase.The results of Western blot showed that the protein expression level of CDK6 in CNE1 cells was lower than that in the control group (0.83±0.25 vs. 0.43±0.21, t=14.67, P=0.003). The protein level of conjugated SUMO1 was significantly lower than that in the control group (2.69±0.48 vs. 1.38±0.31, t=17.22, P=0.001), while the level of free SUMO1 protein was significantly higher than that in the control group (2.01±0.43 vs. 2.60±0.59, t=15.45, P=0.002).The LC50 of CNE1 cells in the control group was significantly lower than that in the hypoxic group (29.44 μg/ml vs. 97.72 μg/ml, t=12.79, P=0.001). After CNE1 cells received 50 μg/ml cisplatin for 48 h, the LDH content in the supernatant of the control group was significantly higher than that in the hypoxic group ((541.49±64.59) ng/ml vs. (234.67±41.03) ng/ml, t=11.94, P=0.007)). The apoptosis rate of CNE1 cells in the control group was significantly higher than that in the hypoxic group ((76.64±5.37)% vs. (32.84±4.77) ng/ml, t=8.49, P=0.003)).@*Conclusion@#Hypoxia can dissociate the covalent modification of CDK6 and SUMO1, inhibit cell cycle and increase the chemotherapy resistance of nasopharyngeal carcinoma.

Tragomycin A Enhances Chemosensitivity to Cisplatin in Ovarian Cancer Cell Lines by Down-regulating STAT3 / 华中科技大学学报(医学版)

Objective@#Our study aimed to investigate the effect of histone deacetylase inhibitor trichostatin A（TSA）on the cisplatin（CDDP） resistance of ovarian cancer cell lines and its molecular mechanism.@*Methods@#Cisplatin-resistant ovarian cancer cell line C13* and its parental line OV2008 were incubated with TSA（200 nmol/L） or/and CDDP（20 μmol/L），the inhibitory rate of tumor cells was determined by MTT assay. Flow cytometry and Western blotting were used to detect apoptosis of tumor cells. Western blotting was also used to detect STAT3 expression in C13* and OV2008 cells. After down-regulation of STAT3 by transfection of STAT3 siRNA in C13* cells，cisplatin-induced apoptosis was evaluated by flow cytometry.@*Results@#MTT assay showed that the proliferation inhibitory rates of the combination group after 48 or 72 h treatment were significantly higher than those of TSA and CDDP groups. The level of STAT3 protein was much higher in C13* cells than in OV2008 cells. Flow cytometry and Western blotting showed that TSA combined with CDDP significantly enhanced the apoptotic rate of C13* cells. STAT3 expression level was significantly higher in C13* cells than in OV2008. Downregulation of STAT3 can significantly improve CDDP-induced apoptosis of C13* cells. @*Conclusion@#Down-regulation of STAT3 by TSA endows cisplatin-resistant cells C13* with increased sensitivity to cisplatin.