Exosome-Transmitted miR-224-5p Promotes Colorectal Cancer Cell Proliferation via Targeting ULK2 in p53-Dependent Manner

Objective To investigate the role and molecular mechanism of exosomal miR-224-5p in colorectal cancer(CRC).Methods The miR-224-5p expression in CRC patient tissues and cell-derived exosomes was measured by laser capture microdissection and qRT-PCR,respectively.Dual-luciferase reporter gene assay was used to determine the target gene of miR-224-5p.The protein expressions of p53 and unc-51 like kinase 2(ULK2)in CRC cells were detected by western blot.Flow cytometry was used to detect cell cycle and apoptosis.Cell proliferation was measured by CCK8 and EdU assay.Results The miR-224-5p expression was upregulated in CRC tissues and increased progressively with the rise of CRC stage.CRC cells secreted extracellular miR-224-5p mainly in an exosome-dependent manner,and then miR-224-5p could be transferred to surrounding tumor cells to regulate cell proliferation in the form of autocrine or paracrine.Moreover,ULK2 was characterized as a direct target of miR-224-5p and was downregulated in CRC tissues.Interestingly,ULK2 inhibited CRC cell proliferation in a p53-dependent manner.Furthermore,exosome-derived miR-224-5p partially reversed the proliferation regulation of ULK2 on CRC cells.Conclusion Our findings demonstrate that exosome-transmitted miR-224-5p promotes p53-dependent cell proliferation by targeting ULK2 in CRC,which may offer promising targets for CRC prevention and therapy.

5-methoxytryptophan induced apoptosis and PI3K/Akt/FoxO3a phosphorylation in colorectal cancer

BACKGROUND Colorectal cancer(CRC)is a highly prevalent malignancy worldwide,and new therapeutic targets urgently need to be found to prolong patient survival.5-methoxytryptophan(5-MTP)is a tryptophan metabolite found in animals and humans.However,the effects of 5-MTP on proliferation and apoptosis of CRC cells are currently unknown.AIM To investigate the effects of 5-MTP on the proliferation,migration,invasion,and apoptosis abilities of CRC cells.Additionally,we seek to explore whether 5-MTP has the potential to be utilized as a drug for the treatment of CRC.METHODS In order to evaluate the effect of 5-MTP on CRC cells,a series of experiments were conducted for evaluation.Colony formation assay and Cell Counting Kit 8 assays were used to investigate the impact of 5-MTP on the proliferation of CRC cell lines.Cell cycle assays were employed to examine the effect of 5-MTP on cellular growth.In addition,we investigated the effects of 5-MTP on apoptosis and reactive oxygen species in HCT-116 cells.To obtain a deeper understanding of how 5-MTP affects CRC,we conducted a study to examine its influence on the PI3K/Akt signaling pathway in CRC cells.RESULTS This article showed that 5-MTP promoted apoptosis and cell cycle arrest and inhibited cell proliferation in CRC cells.In many articles,it has been reported that PI3K/Akt/FoxO3a signaling pathway is one of the most important signaling pathways involved in internal regulating cell proliferation and differentiation. Nevertheless, 5-MTP combined with PI3K/Akt/FoxO3a signaling pathway inhibitors significantly promotedapoptosis and cell cycle arrest and inhibited cell proliferation in CRC cells compared with 5-MTP alone in ourstudy.CONCLUSIONTherefore, there is strong evidence that 5-MTP can be used as an effective medicine for CRC treatment.

Integration of scRNA-Seq and Bulk RNA-Seq to analyze the heterogeneity ofcolorectal cancer immune cells and establish a molecular risk model

Background:Colorectal cancer(CRC)is a highly heterogeneous malignant tumor that significantly impacts clinical diagnosis and treatment.Single-cell RNA sequencing is an innovative method for exploring tumor heterogeneity and understanding its role at cellular and genetic levels.Method:The colorectal cancer Single-cell RNA sequencing data were analysed on the immune.RNA-seq data in bulk form was utilized to assess the major genes of the immune cell subsets linked to CRC.We conducted an analysis of the abundance of immune cells in the microenvironment of CRC,and also performed weighted gene co-expression network analysis.Gene set enrichment analysis helped perform two analytical procedures of subtype groups.Furthermore,Least absolute shrinkage and selection operator regression was employed to analyse and screen for a gene signature.Finally,quantitative PCR Was performed to detect the expression levels of signature genes in CRC.Results:The Single-cell RNA sequencing(GSE146771)dataset was integrated to obtain 9 cell clusters.The Single-sample gene set enrichment analysis showed that the related gene expression of T-cell subsets of different functional statuses could vary greatly between patients with GSE146771.Immune cell analysis of TCGA-CRC indicated an improved overall survival rate for patients with elevated Th2 cell abundance.Five-gene signature(Risk Score=-0.205×CDC25C-0.231×GSTCD-0.010×KPNA2-0.002×KIF15-0.171×ORC1)was developed by weighted correlation network analysis,and lasso Cox regression.Then,the risk prediction efficacy of the signature was validated in four GSE datasets.Furthermore,the expression of five genes was reduced in CRC tissue by quantitative PCR.Conclusion:Five-gene signature based on CRC heterogeneity was developed as a prognosis predictor,which can serve as a potential treatment target.

Leucine-rich repeat-containing G protein-coupled receptor 5 marks different cancer stem cell compartments in human Caco-2 and LoVo colon cancer lines

BACKGROUND Colon cancer cell lines are widely used for research and for the screening of drugs that specifically target the stem cell compartment of colon cancers.It was reported that colon cancer carcinoma specimens contain a subset of leucine-rich repeatcontaining G protein-coupled receptor 5(LGR5)-expressing stem cells,these socalled“tumour-initiating”cells,reminiscent in their properties of the normal intestinal stem cells(ISCs),may explain the apparent heterogeneity of colon cancer cell lines.Also,colon cancer is initiated by aberrant Wnt signaling in ISCs known to express high levels of LGR5.Furthermore,in vivo reports demonstrate the clonal expansion of intestinal adenomas from a single LGR5-expressing cell.AIM To investigate whether colon cancer cell lines contain cancer stem cells and to characterize these putative cancer stem cells.METHODS A portable fluorescent reporter construct based on a conserved fragment of the LGR5 promoter was used to isolate the cell compartments expressing different levels of LGR5 in two widely used colon cancer cell lines(Caco-2 and LoVo).These cells were then characterized according to their proliferation capacity,gene expression signatures of ISC markers,and their tumorigenic properties in vivo and in vitro.RESULTS The data revealed that the LGR5 reporter can be used to identify and isolate a classical intestinal crypt stem cell-like population from the Caco-2,but not from the LoVo,cell lines,in which the cancer stem cell population is more akin to B lymphoma Moloney murine leukemia virus insertion region 1 homolog(+4 crypt)stem cells.This sub-population within Caco-2 cells exhibits an intestinal cancer stem cell gene expression signature and can both self-renew and generate differentiated LGR5 negative progeny.Our data also show that cells expressing high levels of LGR5/enhanced yellow fluorescent protein(EYFP)from this cell line exhibit tumorigenic-like properties in vivo and in vitro.In contrast,cell compartments of LoVo that are expressing high levels of LGR5/EYFP did not show these stem cell-like properties.Thus,cells that exhibit high levels of LGR5/EYFP expression represent the cancer stem cell compartment of Caco-2 colon cancer cells,but not LoVo cells.CONCLUSION Our findings highlight the presence of a spectrum of different ISC-like compartments in different colon cancer cell lines.Their existence is an important consideration for their screening applications and should be taken into account when interpreting drug screening data.We have generated a portable LGR5-reporter that serves as a valuable tool for the identification and isolation of different colon cancer stem cell populations in colon cancer lines.

ABCG5-positivity in tumor buds is an indicator of poor prognosis in node-negative colorectal cancer patients

AIM:To analyze the expression of 8 putative cancer stem cell(CSC) markers within colorectal cancer tumor buds and to determine their prognostic impact in patients with this disease. METHODS:Immunohistochemistry was performed on 101 colorectal cancer resections for CK22(to identify tumor buds) as well as CD133,CD166,CD24,CD44s,CD90,EpCAM,ALDH1,and ABCG5,and their expression within tumor buds was evaluated. RESULTS:CD90,CD44s,and CD133 expression in tumor buds was found in less than 5%of all cases. ALDH1,CD24,CD166 were expressed in 16.5%,16.2%,and 34%cases,respectively,while ABCG5 and EpCAM expression was more frequent and found in 35%and 69%of cases,respectively.Of the 8 markers studied,EpCAM and ABCG5 positivity in tumor buds were significantly associated with poor prognosis(P=0.023,P=0.038,respectively) in multivariable analysis with pT and pN classificationP=0.048;hazard ratio(HR) :2.64;95%CI:1.0-6.9,for EpCAM and P=0.029;HR:2.22;95%CI:1.0-4.5,for ABCG5.Poor survival time was particularly striking for lymph node-negative patients with ABCG5-positive buds(P<0.001) . CONCLUSION:Expression of putative stem cell markers EpCAM and ABCG5 within the tumor buds of colorectal cancer are frequently noted and are associated with poor prognosis.

Role of doublecortin-like kinase 1 and leucine-rich repeat-containing G-protein-coupled receptor 5 in patients with stage Ⅱ/Ⅲ colorectal cancer:Cancer progression and prognosis

BACKGROUND Cancer stem cells(CSCs)are a subpopulation of cancer cells with the potential of self-renewal and differentiation.CSCs play critical roles in tumorigenesis,recurrence,metastasis,radiation tolerance and chemoresistance.AIM To assess the expression patterns and clinical potential of doublecortin-like kinase 1(DCLK1)and leucine-rich repeat-containing G-protein-coupled receptor 5(Lgr5),as prognostic CSC markers of colorectal cancer(CRC).METHODS The expression of DCLK1 and Lgr5 in CRC tissue sections from 92 patients was determined by immunohistochemistry.Each case was evaluated using a combined scoring method based on signal intensity staining(scored 0-3)and the proportion of positively stained cancer cells(scored 0-3).The final staining score was calculated as the intensity score multiplied by the proportion score.Low expression of DCLK1 and Lgr5 was defined as a score of 0-3;high expression of DCLK1 and Lgr5 was defined as a score of≥4.Specimens were categorized as either high or low expression,and the correlation between the expression of DCLK1 or Lgr5 and clinicopathological factors was investigated.RESULTS DCLK1 and Lgr5 expression levels were significantly positively correlated.CRC patients with high DCLK1,Lgr5 and DCLK1/Lgr5 expressions had poorer progression-free survival and overall survival.Moreover,high expression of DCLK1 was an independent prognostic factor for recurrence and overall survival in patients with CRC by multivariate analysis(P=0.026 and P=0.049,respectively).CONCLUSION DCLK1 may be a potential CSC marker for the recurrence and survival of CRC patients.

Predicting Adjuvant Chemotherapy Outcome by Simultaneous Analysis of Thymidylate Synthase Expression and p53 Nuclear Accumulation in Colorectal Cancer

Studies have shown that the tumor suppressor gene p53 may regulate thymidylate synthase (TS) activity in colorectal cancer (CRC) cells, hence attributed to chemo-resistance to 5-flurouracil in CRC. In this study, a total of 299 primary CRC patients who underwent surgery alone or received an adjuvant 5-FU-based chemotherapy were retrospectively studied. TS expression and p53 nuclear accumulation on paraffin embedded primary tumor tissue arrays were immunohistochemically assessed, and their relationship to patient overall survival (OS) and disease free survival (DFS) were analyzed. No correlation was found between TS and p53 expression. p53 nuclear accumulation was significantly correlated with tumor location. In all, multivariate analysis shows that TNM stage is a good indicator of patient survival. TS or p53 is not an independent prognostic or predictive factor in the CRCs. In chemotherapy-treated group, simultaneous analysis of TS and p53 indicates patients in the p53-/TS- or p53+/TS+ group have significant better OS and DFS than the group p53-/TS+ or p53+/TS- (P < 0.01). Thus, our study suggests that simultaneous evaluation of both TS and p53 can help to predict the therapeutic effect of CRCs with 5-FU-based adjuvant chemotherapy.

结肠癌耐药细胞株LoVo/5-Fu中microRNA表达的初步研究

目的建立结肠癌细胞耐药模型LoVo/5-FU并初步筛选可能的耐药相关的microRNA。方法采用5-FU浓度递增法建立人结肠癌细胞耐药模型LoVo/5-FU,观察其生长规律并绘制细胞生长曲线;用MTT法鉴定耐药细胞株耐药性并计算耐药指数(RI);用microRNA芯片技术检测耐药细胞株LoVo/5-FU与其亲本细胞株LoVo中mi-croRNA的表达谱,筛选差异表达的microRNA;用实时荧光定量PCR方法对筛选出的部分差异microRNA在耐药细胞及其亲本细胞中的表达情况进行验证。结果 LoVo/5-FU细胞与LoVo细胞相比,生长缓慢,细胞体积增大,耐药株LoVo/5-FU细胞相对于其亲本LoVo细胞的耐药倍数为8.08。microRNA芯片的结果显示,耐药株LoVo/5-FU细胞与亲本LoVo细胞比较,有10个microRNA表达上调,13个microRNA表达下调;实时荧光定量pcr的结果进一步证实mir-210、mir196a、mir-1281在LoVo/5-FU中显著上调,而let-7f、mir-1228显著下调,其中mir-210在LoVo/5-FU与LoVo中的表达有明显差异。结论 LoVo/5-FU细胞株耐药性稳定,筛选获得的差异miRNA可能通过调控其靶基因而参与人结肠癌细胞对5-Fu的耐药,为进一步研究microRNA在结肠癌耐药机制中的作用奠定基础。

RNA干扰沉默survivin基因提高大肠癌LOVO细胞对5-FU敏感性的研究

目的研究以survivin为靶标的小干扰RNA(siRNA)与化疗药5-氟尿嘧啶(5-FU)联合应用抑制LOVO细胞增殖的作用。方法利用筛选出的有效siRNA干扰survivin基因的靶序列,以脂质体为载体,将survivin siRNA转染至人大肠癌LOVO细胞中,用cell countingkit-8(CCK-8)法染色并计算5-FU及siRNA联用5-FU对LOVO细胞的抑制率。结果单用5-FU处理细胞,其IC50为0.56μg/mL,而加入5pmol siRNA后,其IC50降为0.28μg/mL,siRNA与5-FU联用对LOVO细胞的抑制作用较单用5-FU明显增强(F=28.4,P<0.01);Q值分析表明survivin siRNA与中低浓度的5-FU联用,有较好的协同作用(Q≥1.15)。结论survivin siRNA可显著增强5-FU对LOVO细胞增殖的抑制,提高肿瘤细胞对化疗药物的敏感性,克服耐药性的产生。

Overexpression of CREPT confers colorectal cancer sensitivity to fluorouracil

AIM To investigate expression of cell cycle-related and expression-elevated protein in tumor(CREPT) in colorectal cancer(CRC) and determine its prognostic value in response to 5-fluorouracil(5-FU).METHODS The relative expression of CREPT in CRC tumor samples was determined using immunohistochemistry. The protein content in cell lines was analyzed by immunoblotting. Cell viability was measured with the CCK-8 assay. Cell cycle and apoptosis analyses were performed with flow cytometry.RESULTS CREPT was overexpressed in CRC tissues and correlated with histological grade. Clinicopathological analysis indicated that CREPT was positively related to tumor progression. Exogenous expression of CREPT stimulated cell proliferation and accelerated the cell cycle. More importantly, high expression of CREPT sensitized CRC cells to 5-FU treatment. Furthermore, we demonstrated that 5-FU elicited significant apoptosis in CREPT-positive cells.CONCLUSION Aberrant overexpression of CREPT contributes to tumorigenesis of CRC by promoting cell proliferation and accelerating the cell cycle, and confers sensitivity to 5-FU. CREPT is a potential prognostic biomarker for 5-FU in CRC.

Disparities in colorectal cancer in African-Americans vs Whites: Before and after diagnosis

There are differences between African-American and white patients with colorectal cancer, concerning their characteristics before and after diagnosis. Whites are more likely to adhere to screening guidelines. This is also the case among people with positive family history. Colorectal cancer is more frequent in Blacks. Studies have shown that that since 1985, colon cancer rates have dipped 20% to 25% for Whites, while rates have gone up for African-American men and stayed the same for African-American women. Overall, African-Americans are 38% to 43% more likely to die from colon cancer than are Whites. Furthermore, it seems that there is an African-American predominance in right-sited tumors. African Americans tend to be diagnosed at a later stage, to suffer from better differentiated tumors, and to have worse prognosis when compared with Whites. Moreover, less black patients receive adjuvant chemotherapy for resectable colorectal cancer or radiation therapy for rectal cancer. Caucasians seem to respond better to standard chemotherapy regimens than AfricanAmericans. Concerning toxicity, it appears that patients of African-American descent are more likely to develop 5-FU toxicity than Whites, possibly because of their different dihydropyridine dehydrogenase status. Last but not least, screening surveillance seems to be higher among white than among black long-term colorectal cancer survivors. Socioeconomic and educational status account for most of these differences whereas little evidence exists for a genetic contribution in racial disparity. Understanding the nature of racial differences in colorectal cancer allows tailoring of screening and treatment interventions.

sAPRIL结合肽对LOVO细胞5-FU化疗敏感性的影响

目的增殖诱导配体(APRIL)与结直肠癌细胞对5-氟尿嘧啶(5-FU)的耐药性密切相关。我们前期已利用噬菌体随机肽库技术成功筛选并人工合成与s APRIL有高亲和力的结合肽。本研究旨在探讨s APRIL结合肽对结直肠癌LOVO细胞5-FU化疗敏感性的影响。方法将LOVO细胞分为PBS组、5-FU组、s APRIL结合肽+5-FU组。采用CCK-8法检测细胞增殖、流式细胞仪测定细胞周期及细胞凋亡。结果 5-FU组和s APRIL结合肽+5-FU组增殖抑制率分别为(37.62±7.07)%、(63.05±2.15)%;流式细胞仪检测各组的细胞周期显示5-FU组阻滞在S期,s APRIL结合肽+5-FU组阻滞在G0/G1期和S期,且S期阻滞效应显著强于5-FU组;三组细胞凋亡率分别为(0.21±0.09)%、(12.80±0.30)%、(17.1±0.66)%。结论 s APRIL结合肽能增强结直肠癌LOVO细胞对5-FU的化疗敏感性,有望成为结直肠癌靶向治疗的新型候选制剂。

Gene Expression Changes in Colorectal Cancer during Metronomic Chemotherapy and High-Concentration Drug Administration

5-fluorouracil (5-FU) and oxaliplatin, either alone or in combination, are widely used in chemotherapy for advanced colorectal cancer. Among chemotherapeutic strategies, metronomic chemotherapy has recently demonstrated promising efficacy against otherwise chemoresistant neoplasms. However, data on the efficacy of metronomic applications in cancer stem cells are lacking. This cell population is characterized by resistance to most chemotherapeutic models. In this study, we investigated the efficacy of metronomic chemotherapy and compared it with high-concentration administration of 5-FU and oxaliplatin and their combination in colon adenocarcinoma cells and colon cancer stem cells. We assessed changes in expression levels of specific genes involved in 5-FU and oxaliplatin resistance (thymidylate synthase, DNA (cytosine-5)-methyltransferase 1, dihydrofolate reductase, serine hydroxymethyltransferase, DNA excision repair protein, dihydropyrimidine dehydrogenase) in relation to drug administration schedule using quantitative real-time polymerase chain reaction. We also examined changes in cell viability. Metronomic chemotherapy showed greater efficacy in gene expression levels in colorectal cancer cells, while high, single-concentration administration was more effective in colon cancer stem cells. Regarding cell viability, no significant change was observed between metronomic and single-dose treatments. These results suggest that metronomic chemotherapy may be more effective than high-dose chemotherapy in some patients with colorectal cancer, though high, single-concentration administration may be more effective against cancer stem cells.

Review of 5-FU resistance mechanisms in colorectal cancer:clinical significance of attenuated on-target effects

The emergence of chemoresistant disease during chemotherapy with 5-Fluorouracil-based(5-FU-based)regimens is an important factor in the mortality of metastatic CRC(mCRC).The causes of 5-FU resistance are multifactorial,and besides DNA mismatch repair deficiency(MMR-D),there are no widely accepted criteria for determining which CRC patients are not likely to be responsive to 5-FU-based therapy.Thus,there is a need to systematically understand the mechanistic basis for 5-FU treatment failure and an urgent need to develop new approaches for circumventing the major causes of 5-FU resistance.In this manuscript,we review mechanisms of 5-FU resistance with an emphasis on:(1)altered anabolic metabolism limiting the formation of the primary active metabolite Fluorodeoxyuridylate(5-Fluoro-2'-deoxyuridine-5'-O-monophosphate;FdUMP);(2)elevated expression or activity of the primary enzymatic target thymidylate synthase(TS);and(3)dysregulated programmed cell death as important causes of 5-FU resistance.Importantly,these causes of 5-FU resistance can potentially be overcome through the use of next-generation fluoropyrimidine(FP)polymers(e.g.,CF10)that display reduced dependence on anabolic metabolism and more potent TS inhibitory activity.

穿琥宁对大肠癌HCT-8/5-FU耐药细胞株逆转作用的研究

目的:探讨中药制剂穿琥宁对HCT-8/5-FU多药耐药细胞株的影响。方法:观察0.4,1.2和2.4mg·mL-1穿琥宁作用下的HCT-8/5-FU多药耐药细胞株生长曲线,MTT法检测上述浓度下的细胞抑制率。MTT法、流式细胞仪PI染色法检测穿琥宁与化疗药物5-氟尿嘧啶(5-FU)、顺铂(DDP)和阿霉素(ADM)联合作用下,对HCT-8-5-FU耐药细胞的毒性作用和凋亡率。流式细胞仪罗丹明染色法和PI染色法探讨穿琥宁的作用机制。结果:0.4mg·mL-1穿琥宁生长曲线与正常对照组无明显差别,1.2mg·mL-1穿琥宁对细胞生长有轻度抑制作用,2.4mg·mL-1浓度有一定抑制,但细胞仍可生长。MTT法检测0.4,1.2,2.4mg·mL-1穿琥宁作用下,HCT-8/5-FU耐药细胞株的抑制率分别为7.2%,13.2%,21%。1.2mg·mL-1穿琥宁与5-FU,DDP,AMD联合作用,与这3种化疗药物单独作用比较细胞凋亡率分别为54.2%/26.4%;42.6%/13.6%;30.8%/14.2%,差异显著(P<0.01)。罗丹明染色法提示穿琥宁的作用机制可能与影响P-170的活性有关。但穿琥宁本身并不诱导凋亡,对细胞周期也无影响。结论:低浓度穿琥宁对HCT-8/5-FU细胞无明显抑制作用;与5-FU,ADM,DDP联合作用,可增加上述化疗药物的毒性作用,使肿瘤细胞的凋亡率增高,其机制可能与抑制P-170功能有关。

TNP-470联合5-FU抑制结肠癌生长的实验研究

背景与目的:新生血管生成是肿瘤生长转移的一个重要条件,本研究通过体内外实验观察血管生成抑制剂TNP-470联合5-氟尿嘧啶(5-fluorouracil,5-FU)对结肠癌生长的影响。方法:采用四甲基偶氮唑盐(MTT)法检测TNP-470和5-FU对LOVO细胞的生长抑制效应,用Burgi法分析联合用药效果。建立结肠癌皮下移植瘤模型,观察TNP-470单独或联合5-FU对移植瘤的生长抑制作用,采用免疫组化和图像分析系统定量检测肿瘤组织中血管内皮生长因子(VEGF)的表达,抗Ⅷ因子抗体标记计数肿瘤微血管密度(MVD)。结果:TNP-470和5-FU对体外培养的LOVO细胞的生长具有抑制作用,半数抑制浓度(IC50)分别为55.8ng/ml和4.6ng/ml,Burgi法分析表明两者联合应用具有协同效应,LOVO细胞生长进一步受到抑制。体内实验表明:各治疗组肿瘤的生长明显受到抑制,而联合治疗组抗瘤作用进一步增强。联合治疗组和5-FU组肿瘤组织中VEGF的表达较对照组显著减少,联合治疗组和TNP-470组肿瘤组织中的MVD与对照组比较也显著降低。结论:TNP-470能够抑制LOVO细胞及其皮下移植瘤的生长和新生血管形成,与5-FU联合应用具有协同作用,可提高抗瘤效应。

槲皮素对5-FU诱导的结直肠癌SW480细胞耐药及自噬调控机制研究

目的:探讨槲皮素(Que)调控5-氟尿嘧啶(5-FU)诱导的结直肠癌SW480细胞耐药及自噬的作用及机制。方法:采用浓度递增诱导法建立5-FU耐药细胞株SW480/5-FU,MTT法设置Que高、中、低剂量组(10、20、40μmol/L)和对照组。MTT法检测各组细胞的5-FU耐药性,TUNEL染色法检测细胞凋亡,免疫荧光检测细胞自噬活性,Western blot检测细胞p糖蛋白(Pgp)、多药耐药相关蛋白1(MRP1)、三磷酸腺苷结合转运蛋白G超家族成员2抗体(ABCG2)、LC3Ⅰ、LC3Ⅱ、p62、丝/苏氨酸激酶(AKT)、p-AKT、雷帕霉素靶蛋白(mTOR)和p-mTOR蛋白表达。结果:5-FU抑制SW480/5-FU细胞的半抑制浓度(IC50)明显高于SW480细胞(P<0.05),耐药指数(RI)=13.74。与对照组相比,Que中、高剂量组5-FU抑制SW480/5-FU细胞的IC50明显下降(P<0.05),耐药逆转倍数分别为2.27和4.03。与对照组相比,Que中、高剂量组细胞抑制率、凋亡率和自噬活性明显升高(均P<0.05),蛋白的表达均明显升高(均P<0.05),P-gp、MRP1、ABCG2、p62、p-AKT/AKT和p-mTOR/mTOR蛋白表达明显下降(均P<0.05)。结论:Que可以以剂量依赖性的方式逆转SW480/5-FU细胞的5-FU耐药性,诱导细胞自噬,其作用机制可能与抑制AKT/mTOR的磷酸化有关。

5-FU对SW480细胞Musashi-1基因表达的影响

目的:观察5-氟尿嘧啶(5-FU)对人结直肠癌细胞株SW480的作用与Musashi-1基因表达变化的关系。方法:用MTT法检测不同时间5-FU对SW480细胞增殖的影响,流式细胞术检测侧群(SP)细胞和CD34+CD44+细胞比例,RT-PCR半定量检测Musashi-1基因表达。结果:5-FU作用于SW480细胞24、48、72 h的半数抑制率依次为32.12、16.2和6.8 mg.L-1,SP细胞比例、CD34+CD44+细胞以及Musashi-1 mRNA表达在5-FU作用后均增加。结论:正常肠道干细胞标记物Musashi-1有可能成为结直肠癌干细胞样肿瘤细胞特异性标记,CD34、CD44可能具有类似的潜力。

奥沙利铂对人结肠癌细胞LoVo和SW480/M5作用的实验研究

目的探讨体外实验奥沙利铂对人结肠癌LoVo和SW480/M5细胞的抑制作用及其可能机制。方法 MTT法检测不同剂量奥沙利铂对LoVo和SW480/M5细胞增殖的抑制作用。流式细胞仪检测1/2GI_(50)和GI_(50)浓度奥沙利铂对LoVo和SW480/M5细胞周期和早期凋亡的影响。原子光谱吸收仪检测GI_(50)浓度奥沙利铂作用4、8、24h后LoVo和SW480/M5细胞DNA含铂量。结果奥沙利铂对LoVo和SW480/M5细胞增殖的抑制作用呈量效依赖;其GI_(50)浓度:LoVo细胞为6.5mg/L,SW480/M5细胞为58.0mg/L。自然对数增殖周期,LoVo细胞中G_1期细胞比例高于、G_2期细胞比例低于SW480/M5细胞(P<0.05)。奥沙利铂浓度GI_(50)时,降低肿瘤细胞G_1期比例,升高LoVo细胞S期比例较SW480/M5细胞明显,升高SW480/M5细胞而降低LoVo细胞G_2/M期比例。1/2GI_(50)、GI_(50)奥沙利铂均可诱导两种肿瘤细胞发生早期凋亡,但1/2GI_(50)L-OHP促凋亡作用两种肿瘤细胞间无统计学差异,GI_(50)L-OHP对LoVo细胞的促凋亡作用高于SW480/M5细胞。GI_(50)L-OHP奥沙利铂使两种肿瘤细胞DNA含铂量显著升高,并呈时效依赖。LoVo细胞DNA交联铂原子能力高于SW480/M5细胞。结论奥沙利铂主要通过阻滞细胞于S期或(和)G_2/M期并诱导细胞凋亡而抑制两种肿瘤细胞增殖。LoVo细胞对奥沙利铂敏感性明显高于SW480/M5细胞。

STAT3磷酸化抑制剂隐丹参酮提高5-FU诱导的结直肠癌细胞凋亡

目的探究结直肠癌细胞中利用信号转导蛋白和转录激活因子3(STAT3)磷酸化抑制剂隐丹参酮(CTS)抑制STAT3 705位点磷酸化对5-氟尿嘧啶(5-FU)效果的影响。方法采用Western印迹法检测5株结直肠癌细胞中STAT3的磷酸化水平,挑选磷酸化程度最高的2株细胞进行后续实验研究。采用Western印迹法检测5-FU处理后结直肠癌细胞STAT3磷酸化水平的变化。应用MTT实验评价5-FU与CTS联合处理结直肠癌细胞对细胞活性影响。利用流式细胞仪检测5-FU与CTS联合处理细胞后对细胞凋亡的影响,同时利用Western印迹法检测抗凋亡蛋白Bcl2的变化情况。结果 5-FU能够降低结直肠癌细胞STAT3 705位点磷酸化水平,利用CTS抑制STAT3磷酸化极大的增强了5-FU的作用效果,降低了结直肠癌细胞活性,促进了细胞凋亡。同时进一步机制研究表明CTS与5-FU联合作用降低了Bcl2蛋白水平。结论结直肠癌细胞中,利用STAT3磷酸化抑制剂CTS抑制STAT3磷酸化水平能够明显提高5-FU的作用效果。