P-糖蛋白(P-gp)与抗癌药物耐药性简述

目前癌症每年导致全球约700万人的死亡,并且这一数字在2030年将增至1700万。大多数病例的死亡是由于抗癌药物耐药性而导致的化疗失败。抗癌药物的耐药性主要分为2种:固有型药物耐药性及获得型药物耐药性。固有型药物耐药性是指患者对于化疗初期就不敏感,而获得型药物耐药则是在治疗过程中发生的耐受性。药物耐药的发生机制主要有多药耐药(MDR)转运体过表达,肿瘤干细胞靶蛋白功能或表达的改变,凋亡信号通路的改变,对药物传递的物理屏障等等。文章将对膜转运体中的多药耐药转运体P-糖蛋白作简要概述。

芳(杂)环并氮杂(氢化)吖啶的合成及其反应机理研究

以1 苄基 3,5 哌啶二酮1为起始原料,通过与邻氨基苯甲醛缩合得3 氮杂吖啶酮2,继续与靛红进行Pfitzing反应给出喹啉并氮杂吖啶3;二酮与α 萘胺和对氯苯甲醛的缩合反应,合成了10 氮杂 7 对氯苯基 六氢苯并[C]吖啶酮4,再经脱氢反应生成10 氮杂 7 对氯苯基 四氢苯并[C]吖啶酮5,并讨论了部分化合物形成的反应机理.所合成的新化合物的结构经红外光谱、核磁共振光谱和元素分析予以证实.

Establishment of a mdr1 Multidrug Resistant Model of Orthotopic Transplantation of Liver Carcinoma on Nude Mice

To develop a new method of inducing mdrl multidrug resistance by establishinga nude mice model of orthotopic transplantation of liver carcinoma by sporadic abdominalchemotherapy at intervals. Methods: Hepatocellular carcinoma HepG2 cell was cultured and injectedsubcutaneously to form the tumor-supplying mice. The tumor bits from the tumor-supplying mice wereimplanted under the envelope of the mice liver and induced by abdominal chemotherapy withPharmorubicin. Physical examination, ultrasonography, spiral CT and operative inspection were usedto examine tumor progression. RT-PCR and immunohistochemistry were adopted to detect the expressionof mdr1-mRNA and its encoded protein P-gp protein (P-gp). Results: There was no operative dead, therate of implanting tumor successfully was 88% (22/25), the rate of implanting secondly successfullywas 100% (3/3), and the rate of inducing successfully was 80% (16/20). The expression of mdrl-mRNAand the P-gp in the inducing group was 23 folds and 13 folds in the control group respectively.Conclusion: We have established an in vivo model of mdr using nude mice transplanted with orthotopicliver neoplasm coupled to chemotherapy.

The status of Chinese medicine in reversing multi-drug resistance of hepatocellular carcinoma

Multi-drug resistance(MDR) is a major obstacle in the chemotherapy of hepatocellular carcinoma.Comparing with western reversal agents,traditional Chinese medicine have advantages of low cost,hypotoxicity,wide safety range,broad-spectrum and multi-targets,etc.Therefore,traditional Chinese medicine may be expected to open up a new path to reverse MDR of liver cancer.Studies about applying traditional Chinese medicine to reverse MDR in hepatocellular carcinoma are outlined below.

Why bortezomib cannot go with ‘green'?

Eat more‘green’or eat‘five a day’is one of the most important healthy lifestyle behaviours in the 21 century.Aiming to fight cancer effectively,more than half patients use vitamins or herbs concurrently with conventional anticancer treatment.Flavonoids or polyphenols existing in vegetables,fruits and green tea are common plant pigments with antioxidant properties and considered acting as cancer preventing or anti-cancer agents.Recently it was found that some flavonoids and vitamin C in diet or supplements have antagonistic effect with the anti-cancer drug bortezomib.Bortezomib is a specific inhibitor for proteasome and is currently used for treatment of relapsed and refractory multiple myeloma.Despite its successful rates in treating multiple myeloma and other solid tumors,it is unable to kill leukemic cells in the blood.It was recently revealed that some flavonoids and vitamin C present in green leaves and green teas in the blood can neutralize bortezomib by directly interaction between two chemicals.Here we summarize why dietary flavonoids should be avoided in patients who take bortezomib as chemotherapeutic drug.

Impact of MTT based tumor chemosensitivity assay in vitro

Objective： The aim of the study was to evaluate the impact of the chemosensitivity assay in vitro and establish a standard process of measuring the anti-cancer drug sensitivity with MTT assay. Methods： Some influencing factors of MTT assay in studying the sensitivity of human peripheral blood mononuclear cells （PBMC） to anti-cancer drugs were observed, including red blood cells, platelets, three different kinds of DMSO and different concentrations of MTT. Meanwhile the stability of tumor drug-coated plate was monitored. Results： The red blood cells and platelets may affect the results at a certain range of concentration. Analytical pure DMSO, both imported and domestic reagents showed the same color with MI3-, and the A values of the reaction were dependent on MTT dose. The stability of the freeze-drying drug-coated plates was superior to non freeze-drying ones. Conclusion： To make clear and definite all kinds of influencing factors might contribute to a kind of standard MTT assay for drug sensitivity test in vitro.

Blockage of IGF-1R signaling sensitizes urinary bladder cancer cells to mitomycin-mediated cytotoxicity

A major problem which is poorly understood in the management of bladder cancer is low sensitivity to chemotherapy and high recurrence after transurethral resection. Insulin-like growth factor 1 receptor (IGF-1R) signaling plays a very important role in progression, invasion and metastasis of bladder cancer cells. In this study, we investigated whether IGF-1R was involved in the growth stimulating activity and drug resistance of bladder cancer cells. The results showed: The mRNAs of IGF-1, IGF-2 and IGF-1R were strongly expressed in serum-free cultured T24 cell line, whereas normal urothelial cells did not express these factors/receptors or only in trace levels; T24 cell responded far better to growth stimulation by IGF-1 than did normal urothelial cells; blockage of IGF1R by antisense oligodeoxynucleotide (ODN) significantly inhibited the growth of T24 cell and enhanced sensitivity and apoptosis of T24 cells to mitomycin (MMC). These results suggested that blockage of IGF-IR signaling might potentially contribute to the treatment of bladder cancer cells which are insensitive to chemotherapy.

The feasibility of antitumor drugs chemosensitivity testing by flow cytometry

Objective: To investigate the feasibility of chemosensitivity testing of antitumor drugs by flow cytometry in clinical applications so as to provide experimental and theoretical basis for the establishment of a novel antitumor drugs sensitivity testing and the screening of particular antitumor drugs. Methods: Detect the apoptosis rate of 12 cases of Molt-4 cell line, 57 cases of fresh clinical gastrointestinal tumor cells by Sub-G1 and Annexin V assay of flow cytometry under the effects of antitumor drugs at different times and the outcomes were compared with the ones of the MTT (3-(4,5-dimethylthiazolyl-2) -2,5-diphenyltetrazolium bromide) assay. Results: The lethality of drugs on Molt-4 cell, clinical gastrointestinal tumor cells had a positive correlation with the acting time of antidrugs by employing Annexin V, Sub-G1 and MTT assay. Drug-incurring maximum lethality of Annexin V assay was higher than MTT colorimetric assay, that of Sub-G1 was lower than MTT assay, the virtual times of Annexin V and Sub-G1 assay were obviously earlier than that of MTT colorimetric assay. Conclusion: Annexin V and Sub-G1 assay of flow cytometry can be taken as potent protocols testing anti-tumor drug chemosensitivity. Annexin V assay is featured by more sensitive, concise, reliable compared with the classical chemosensitivity testing assay of MTT colorimetric assay and it possesses clinical applied value.

CUMULATIVE RESULTS OF CHEMOSENSITIVITY TEST USING MTT ASSAY IN DOUBLE-LAYER AGAROSE

Objective To investigate cumulative results of chemosensitivity test using 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyl （MTT） assay in double-layer agarose. Methods A total of 2 491 patients with different kinds of cancers were enrolled in the study, in which 18 kinds of different anticancer drugs were used. A computer soft was used to get charts. ResultsThe total evaluability rate was 82.7% （2 060/2 491）. Among all agents, the efficiency rates of 5-Fu, MMC, DDP, BLM and CBP were higher than the efficiency rates of others. The response rate range of different cancer in vitro sensitivity by using MTT assay in double layer agarose were from 9.2% （biliary duct） to 37.5% （malignant lymphoma）. For colon and rectum cancer, 5-Fu, DDP, MMC and BLM were more sensitive than other anti-tumor agents. For breast carcinomas, ACTD and DDP were more sensitive. For gastric cancer, 5-Fu, DDP and BLM were more sensitive. For leukemia, VM-26 and HHRT were more sensitive. ACM was more sensitive to kidney and MXT and BLM were more sensitive to pancreas cancer. For Lung cancer, DDP and EPI were more sensitive. Mean true positive rate, mean true negative rate, mean sensitivity, mean specificity and mean accuracy were 44% , 92% , 72% , 77% , and 76% , respectively. Conclusion Chemosensitivity tesing using the MTT assay in a double layer agarose was a very useful reference to chem- therapy.

Therapeutic resistance in cancer: microRNA regulation of EGFR signaling networks

Receptor tyrosine kinases(RTKs)such as the epidermal growth factor receptor(EGFR)regulate cellular homeostatic processes.EGFR activates downstream signaling cascades that promote tumor cell survival,proliferation and migration.Dysregulation of EGFR signaling as a consequence of overexpression,amplification and mutation of the EGFR gene occurs frequently in several types of cancers and many become dependent on EGFR signaling to maintain their malignant phenotypes.Consequently,concerted efforts have been mounted to develop therapeutic agents and strategies to effectively inhibit EGFR.However,limited therapeutic benefits to cancer patients have been derived from EGFR-targeted therapies.A well-documented obstacle to improved patient survival is the presence of EGFR-inhibitor resistant tumor cell variants within heterogeneous tumor cell masses.Here,we summarize the mechanisms by which tumors resist EGFR-targeted therapies and highlight the emerging role of microRNAs(miRs)as downstream effector molecules utilized by EGFR to promote tumor initiation,progression and that play a role in resistance to EGFR inhibitors.We also examine evidence supporting the utility of miRs as predictors of response to targeted therapies and novel therapeutic agents to circumvent EGFR-inhibitor resistance mechanisms.

The difference between multi-drug resistant cell line H460/Gem and its parental cell NCI-H460

Objective： To discuss the difference between multi-drug resistant cell line H460/Gem and its parental cell NCl-H460 on the basis of establishment of human gemcitabine-resistant cell line H460/Gem so as to elaborate the possible mechanisms of gemcitabine resistance. Methods： Human gemcitabine-resistant non-small cell lung cancer cell line H460/Gem was established by 2/3 clinical serous peak concentration gemcitabine intermittent selection from its parental cell human large cell lung carcinoma cell line NCl-H460 which was sensitive to gemcitabine. During the course of inducement, we had monitored their morphology, checked their resistance indexes and resistant pedigree by MTT method, gathered their growth curves and calculated their doubling time, examined their DNA contents and cell cycles by FCM; at the same time, we had measured its expressions of P53, EGFR, c-erb-B-2, PTEN, PCNA, c-myc, VEGF, MDR-1, Bcl-2, nm23, MMP-9, TIMP-1, CD44v6 proteins via immunocytochemistry staining, RRM1 and ERCC1 mRNA by real-time fluorescent quantitative-PCR. Results： The resistance index of H460/Gem＇ cells （the deputy of cells in the process of inducement） to gemcitabine was 1.201, and the cell line also exhibited cross-resistance to paclitaxol, fluorouraci, etoposide, cisplatin and oxaliplatin, but kept sensitivity to vinorelbine and taxotere. The doubling time of H460/Gem＇ cells was longer and figures in G0-G1 phase was decreased than that of NCl-H460 cells. Compared with NCl-H460 cells, H460/Gem＇ cells had achieved TIMP-1 protein expression emerged, nm23 protein expression enhanced, VEGF and MMP-9 protein expressions reduced, and CD44v6, P53 protein expressions vanished, but expressions of EGFR, c-erb-B-2, PTEN, PCNA, c-myc, MDR-1, Bcl-2 proteins and RRM1, ERCC1 mRNA changed trivially. The resistance index of H460/Gem cells to gemcitabine was 1.644, and the ceil line also exhibited cross-resistance to fluorouraci, cisplatin and oxaliplatin, but kept sensitivity to paclitaxol, vinorelbine, taxotere, and etoposide. The doubling time of H460/Gem cells was longer and figures in G0-G1 phase was decreased than those of NCl-H460 cells. The farther studies indicated that, compared with NCl-H460 cells, the expressions of MDR-1, nm23 and Bcl-2 proteins in H460/Gem cells had been enhanced, c-erb-B-2 protein expression emerged, P53, MMP-9 and VEGR protein expression had been weakened, but the changes of PTEN, PCNA, c-myc, TIMP-1, EGFR, CD44v6 protein, RRM1 mRNA and ERCC1 mRNA expressions were trivial. Furthermore, compared with its parental cells, H460/Gem cells were mixed with giant cells of different sizes that were larger and more irregular. Conclusion： The human gemcitabine-resistant non-small cell lung cancer cell line H460/Gem had achieved multi-drug resistance and great changes of biological characters compared with its parental cells. And these changes possibly participated in the formation of multidrug resistance.

Antitumor drug-induced acute pancreatitis:report of a special case

Drug-induced acute pancreatitis （DAP） is defined as pancreatitis with corresponding clinical manifestations resulted from drug-induced pancreatic secretion dysfunction and pancreatic tissue damage. One case of DAP resulted from chemotherapeutics （Nimustine） was diagnosed and treated our in hospital in 2009. This patient belonged to pancreatitis induced by anticancer drugs, and the toxicity of anticancer drugs acted directly on pancreatic cells, leading to the occurrence of pancreatitis. After treatment, the pancreatitis was effectively treated in this patient, but the final the patient and his family eventually gave up the treatment due to aggravated primary diseases

Effect of Therapeutic Ginger on Genotoxic of Taxol Drug （Anti-Cancer） in Bone Marrow Cell of Male Mice

Medicinal use of spices/herbs has been gradually increased in the developed countries, Zingiber officinale （Ginger） is known to possess potent antioxidant and anti inflammatory properties. Therefore, the aim of this study is to determine the possible anti-mutagenic effect of ginger against the genotoxic effect of anti-cancer drug Taxol 0.6 mg/kg. This study is conducted by using two types of cytogenetic studies in bone marrow cell of mal albino mice Mus musculus （average weight 25-30 g）. The animals were randomly distributed into six groups, each of 14 mi[ce, （GI） was given the solvent, （G2） treatment of the medical dose of Taxol drug, （G3） treatment of ginger, （G4） a pre-treatment of ginger prior to treatment of drug, （G5） a simultaneous treatment of ginger and treatment of drug, （G6） a post-treatment of ginger after treatment drug. The study results show that significant increase in total chromosomal aberrations and significant increase in the number of micronuclei were observed after treatment drug. The significant structural aberrations were in the form of end-to-end associations. The numerical chromosomal aberrations were endomitosis and polyploid. The results showed that the frequencies of chromosomal aberrations and micronuclei in ginger treated group were not significantly different from control. Simultaneous treatment of ginger was found to be effective in reducing the genotoxic effects induced by drug Taxol especially in the total number of the chromosomal aberrations and the number of micronuclei.