MicroRNA‐375‐3p enhances chemosensitivity to 5‐fluorouracil by targeting thymidylate synthase in colorectal cancer

Resistance to chemotherapy is a major challenge for the treatment of patients with colorectal cancer (CRC). Previous studies have found that microRNAs (miRNAs) play key roles in drug resistance; however, the role of miRNA‐373‐3p (miR‐375‐3p) in CRC remains unclear. The current study aimed to explore the potential function of miR‐375‐3p in 5‐fluorouracil (5‐FU) resistance. MicroRNA‐375‐3p was found to be widely downregulated in human CRC cell lines and tissues and to promote the sensitivity of CRC cells to 5‐FU by inducing colon cancer cell apoptosis and cycle arrest and by inhibiting cell growth, migration, and invasion in vitro. Thymidylate synthase (TYMS) was found to be a direct target of miR‐375‐3p, and TYMS knockdown exerted similar effects as miR‐375‐3p overexpression on the CRC cellular response to 5‐FU. Lipid‐coated calcium carbonate nanoparticles (NPs) were designed to cotransport 5‐FU and miR‐375‐3p into cells efficiently and rapidly and to release the drugs in a weakly acidic tumor microenvironment. The therapeutic effect of combined miR‐375 + 5‐FU/NPs was significantly higher than that of the individual treatments in mouse s.c. xenografts derived from HCT116 cells. Our results suggest that restoring miR‐375‐3p levels could be a future novel therapeutic strategy to enhance chemosensitivity to 5‐FU.     

The effect of hydrolytic enzymes on the acetylcholine sensitivity of the skeletal muscle cell membrane

Isometric tension developed by rat soleus and extensor digitorum longus (EDL) muscles in response to acetylcholine (Ach) applied in vitro was recorded. Tension of contractures elicited in response to Ach increased after muscles had been incubated with phospholipase C, pepsin, or soluble fractions prepared from muscle homogenate.Using intracellular microelectrodes, resting membrane potential (RMP) and depolarisation in response to Ach added to the bathing medium were recorded in endplate-free regions of the muscle fibres. No significant change in RMP was observed in muscles incubated with soluble muscle fraction or phospholipase C, but depolarisation in response to Ach or carbachol was significantly increased. The time course for the increase in depolarisation and the contracture response to Ach was similar.When all available receptors were blocked with -bungarotoxin prior to incubation so that no response to Ach could be elicited, with subsequent incubation in muscle soluble fraction or phospholipase C, both contractures and depolarisation in response to Ach returned. These results support the hypothesis that receptors, not previously available to interact with Ach or -bungarotoxin were revealed following incubation.     

eIF3S10在肺癌组织中的表达及与化疗反应的关系

目的:研究eIF3S10在肺癌中的表达及其与化疗反应的关系,探讨其在肺癌预后中的作用。方法:收集在湖南省肿瘤医院治疗的31例支气管纤维镜检肺癌组织和20例肺良性病变组织及10例肺癌边缘正常组织的石蜡组织切片。采用免疫组织化学技术检测eIF3S10蛋白在肺癌组织、肺良性病变组织和正常肺组织中的表达,并分析eIF3S10表达水平与患者化疗敏感性的关系。结果:肺正常组织和肺良性病变组织中eIF3S10阳性率分别为30%和15%,而肺癌组织中eIF3S10的阳性率达61%。eIF3S10表达水平与化疗敏感性存在一定相关性。结论:肺癌组织中有eIF3S10过表达,而肿瘤组织eIF3S10表达过高可能提示患者对化疗反应敏感。     

人恶性肿瘤培养细胞抗癌基因P53功能状态与肿瘤化疗敏感性的关系

目的：探讨人恶性肿瘤培养细胞抗癌基因P53功能状态与化疗敏感性的关系。方法：采用用大肠癌、肺癌、食管癌、多发性骨髓瘤、白血病5种人体肿瘤培养细胞共20株,经P53功能检测方法确认P53功能状态,用MTT法检测P53不同功能状态下,各种肿瘤细胞对化疗药VP－16的敏感性及差异。结果：以VP－16的IC50值计算,P53功能正常的肿瘤细胞株大多比同类肿瘤P53功能丧失的细胞株高58倍,显示出较高的化疗敏感性。结论：人体多种恶性肿瘤培养细胞P53功能状态直接影响其化疗敏感性。     

ATP生物发光法与MTT法检测卵巢癌体外化疗敏感性的比较

目的比较ATh法与MTT（四唑蓝）法对卵巢癌细胞体外化疗敏感性的预测价值。方法分别以ATP法和MTF法检测5种化疗药物对卵巢癌3AO细胞株的抑制作用。结果（1）ATP法与MTT法相关性良好（r＝0．9031）。（2）ATP法更加灵敏、稳定。ATP法在80个细胞时即可测出发光强度的改变;而MTT法细胞数达300时才能测出OD值变化。试验所需细胞浓度,ATP法与MTT法分别为1×104－5×104个／ml和1×106-5×106个／ml,ATP法比MTT法低得多。结论ATP法作为检测卵巢癌细胞体外化疗敏感性的手段优于MTT法。     

Heterogeneity ofin vitro chemosensitivity in perioperative breast cancer cells to mitoxantroneversus doxorubicin evaluated by a microplate ATP bioluminescence assay

Summary Apart from clinical trials, mitoxantrone (MX) is rarely used in breast cancer (BC) due to the anticipated anthracycline cross-resistance. We have examined this drug versus doxorubicin (DOX) using data obtained fromin vitro microplate ATP tumor chemosensitivity assays (ATP-TCA) of BC cells which were derived from 55 chemotherapy-naive patients at time of primary surgery. Both drugs were tested at 6 different concentrations ranging from 6.25% to 200% peak plasma concentrationin vivo (PPC). Differences between DOX and MX observed for mean IC₅₀, IC₉₀, and a sensitivity index (SI) were not statistically significant.In vitro response rates were 44% for DOX and 52% for MX. 34 of 52 eligible assays (65%) showed comparable activity of both drugs whereas a lack of cross-resistance was observed in the remaining 18 (35%) tumors as indicated by differences for SI. Cumulative concentration-response plots of tumors respondingin vitro with a 50 percent or 90 percent tumor cell inhibition showed a strong dose-dependence for both DOX and MX at concentrations which normally can be achieved within clinical tumors (i.e. 6.25%-50% PPC). At higher concentrations, however, cytotoxicity of DOX and MX could not be improved by furtherin vitro dose escalation. Moreover, a substantial proportion of BC specimens (DOX: 48.1%; MX: 40.4%) did not experience a 90 tumor cell inhibition at 200% PPC. In conclusion,in vitro results obtained by ATP-TCA indicate that there is no cross-resistance between MX and DOX in a substantial proportion of BC patients. This may be clinically useful and suggests that combinations including MX should be tested in patients clinically resistant to DOX containing regimens. Since both drugs produced sigmoidal concentration-response curves, dose escalation beyond a certain point may not produce increased sensitivity.     

MTT药敏试验在老年急性白血病化疗中的应用

目的 探讨老年急性白血病治疗个体化化疗方案。方法 从21例老年急性白血病患者的外周血或骨髓中分离出白血病细胞进行体外原代培养，用MTT法检测柔红霉素、高三尖杉酯碱、阿克拉霉素、米托蒽醌、阿糖胞苷、足叶乙苷、鬼臼噻吩甙、羟基喜树碱、甲氨喋呤等九种单药药敏试验，并参照药敏试验制定化疗方案，进行化疗。结果 21例患者中有一种或一种以上药物敏感者16例占76.2％，九种药物均耐药者5例占23.8％。16例接受药敏指导下化疗，6例完全缓解(CR)，CR率37.5％，4例部分缓解(PR)，PR率25％，有效率62.5％。总符合率81.3％，阳性符合率84.6％，阴性符合率66.％。结论 MTT药敏试验对于老年急性白血病选择个体化的化疗方案有指导意义。     

肿瘤体外药敏试验及其与临床用药之间的关系

目的：研究肿瘤体外药敏试验(MTT法)与临床用药之间的关系。方法：将210例5种肿瘤标本(85例卵巢癌、30例宫颈癌、26例胃癌、41例结直肠癌、28例乳腺癌)的体外药敏试验(MTT法)结果进行分析：比较同一药品对同一种肿瘤标本不同病例的抑制率差异，计算每一种肿瘤标本相对于每一种药物的抑制率的平均值，筛选出平均抑制率较大的药物，与临床上常用于该肿瘤的药物进行比较。结果：肿瘤体外药敏存在明显个体差异，其抑制率差异可达0～60％以上，而其平均抑制率结果与临床用药经验比较符合，体外试验较敏感同时临床较常用的药物主要有卵巢癌：用紫杉醇(Taxol)、顺铂(DDP)等；宫颈癌：用DDP、表柔比星(e-ADM)、丝裂霉素(MMC)等；胃癌：用DDP、氟尿嘧啶(5-FU)、博来霉素(BLM)、MMC等；结直肠癌：用DDP、MMC、BLM、5-FU等；乳腺癌：用e—ADM、多柔比星(ADM)、长春瑞滨(NVB)等。结论：肿瘤体外药敏试验结果可以为临床个体化治疗提供参考。     

MTT法药敏试验应用于晚期乳腺癌

[目的]探讨MTT法体外药敏试验在复发转移性乳腺癌化疗中的价值。[方法]取40例复发转移性乳腺癌患者肿瘤组织，以简易机械法制备细胞悬液，应用MTT法体外药敏试验测定其对10种常用化疗药物的敏感性，并指导临床用药，同时与临床疗效进行相关分析。[结果]MTT法检测复发转移乳腺癌患者药敏试验的成功率为92．5％，敏感性为87．5％，特异性为69．2％。阳性预测值为84.0%,阴法预测值为75％，总的预测准确率为81．1％。[结论]MTT简便快速，可作为临床上指导复发转移乳腺癌个体化化疗的有效方法．     

增殖细胞核抗原与卵巢癌细胞系化学敏感性的关系

目的　探讨增殖细胞核抗原 (PCNA)与上皮性卵巢癌细胞系化学敏感性的关系。方法　使用顺铂作用于A 2 780及AD 60细胞株。在MTT法测定耐药倍数基础上 ,用ABC检测PCNA表达。结果　MTT测定AD 60的耐药倍数为 2 .4。A 2 780PCNA的表达低于AD 60 ,且随药物浓度的递增染色较耐药组明显变浅。A 2 780、AD 60相同药物浓度作用后PCNA的表达有显著差异 (P <0 .0 1) ;同一细胞株不同药物浓度作用后PCNA表达有显著性差异 (P <0 .0 1)。结论　增殖细胞核抗原表达与上皮性卵巢癌细胞对细胞毒性药物的化学敏感性呈负相关。