Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cancer cells may frequently develop cross-resistance to structurally dissimilar chemotherapeutic agents. However, the molecular mechanisms for sensitivity and resistance of tumor cells towards chemotherapy are still partially understood. Antineoplasic drugs have been shown to induce apoptosis in chemosensitive leukemias and solid tumors. In this work, cross-resistance among vincristine (VCR), doxorubicin (DOX) and other antineoplasic agents commonly used in the treatment of leukemia such as etoposide (VP-16), methotrexate (MTX), cyclophosphamide (CTX), dexamethasone (DEX), cytarabine (Ara-C) and L-asparaginase on vincristine resistant (LBR-V160), doxorubicin resistant (LBR-D160) and sensitive (LBR-) murine leukemic T cell lines, was determined. The effect of antineoplasic agents was assayed by tritiated thymidine incorporation. Our results showed that VCR exhibited cross-resistance with DOX, VP-16, DEX and MTX, while DOX demonstrated cross-resistance with VCR, VP-16 and MTX. Ara-C failed to present cross-resistance with any cell line. Apoptosis induced by the above drugs on the same cell lines was analyzed by acridine orange and ethidium bromide staining, DNA hypoploidy (flow cytometry) and oligonucleosomal fragmentation of nuclear DNA showing that therapeutic concentrations of these chemotherapeutic agents induced apoptosis in the LBR- cell line. Our results demonstrated that, except for DEX, none of the drugs presenting cross-resistance were able to induce cell death on LBR-V 160 or LBR-D 160 cell lines.
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PMID:Correlation between decreased apoptosis and multidrug resistance (MDR) in murine leukemic T cell lines. 1169 8

AIM:To construct Hsp90 antisense RNA eukaryotic expression vector, transfect it into SGC7901 and SGC7901/VCR of MDR-type human gastric cancer cell lines, HCC7402 of human hepatic cancer and Ec109 of human esophageal cancer cell lines, and to study the cell cycle distribution of the gene transected cells and their response to chemotherapeutic drugs.METHODS:A 1.03kb cDNA sequence of Hsp90beta was obtained from the primary plasmid phHSP90 by EcoR I and BamH I nuclease digestion and was cloned to the EcoR I and BamH I site of the pcDNA by T4DNA ligase and an antisense orientation of Hsp90beta expression vector was constructed. The constructs were transfected with lipofectamine and positive clones were selected with G418. The expression of RNA was determined with dot blotting and RNase protection assay, and the expression of Hsp90 protein determined with western blot. Cell cycle distribution of the transfectants was analyzed with flow cytometry, and the drug sensitivity of the transfectants to Adriamycin (ADR), vincrinstine (VCR), mitomycin (MMC) and cyclophosphamide (CTX) with MTT and intracellular drug concentration of the transfectants was determined with flow cytometry.RESULTS:In EcoR I and BamH I restriction analysis, the size and the direction of the cloned sequence of Hsp90beta remained what had been designed and the gene constructs were named pcDNA-Hsp90.AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 cell clones all expressed Hsp90 anti-sense RNA. The expression of Hsp90 was down-regulated in AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 cell clones. Cell cycle distribution was changed differently. In AH-SGC7901/VCR and AH-Ec109 cells, G(1) phase cells were increased; S phase and G(2) phase cells were decreased as compared with their parental cell lines. In AH-SGC7901 cell, G(1)phase cells were decreased, G(2) phase cells increased and S phase cells were not changed, and in AH-HCC7402 cells G(1), S and G(2) phase cells remained unchanged as compared with their parental cell lines. The sensitivity of AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 to chemotherapeutic drugs, the sensitivity of AH-SGC7901/VCR to ADR, VCR, MMC and CTX the sensitivity of AH-HCC7402 to ADR and VCR, and the sensitivity of Ec109 to ADR, VCR and CTX all increased as compared with their parental cell lines. The mean fluorescence intensity of ADR in AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 was also significantly elevated (P < 0.05).CONCLUSION: Down-regulation of Hsp90 could change cell cycle distribution and increase the drug sensitivity of tumor cells.
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PMID:Down-regulation of Hsp90 could change cell cycle distribution and increase drug sensitivity of tumor cells. 1181 30

Hyperthermia is a powerful tool for enhancing the effect of many chemical drugs on killing cells, but too many times of hyperthermia could decrease the effect and increase the ability of tumor cell against chemical drugs. Heat stress protein 70(HSP70) mRNA of K562 cell was analyzed by RT-PCR, and the chemosensitivity of K562 cell was tested by MTT method before and after heat-exposure. The results showed that HSP70 mRNA increased greatly after K562 cells exposed to 40 degrees C for 30 min and then it went to the top after 120 min heat-exposure. The sensitivity of K562 cell to adriamycin (ADM) and cyclophosphamide (CTX) in a usual dosage (1/250 of one dosage in clinical use) was in middle degree before exposed to heat, and the sensitivity dramatically went down after K562 cell being heat-stressed. The sensitivity of heat-stressed tumor cells to chemotherapeutic drugs was decreased, which may come from the increased expression of stress proteins in cells.
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PMID:[Preheating decrease the sensitivity of K562 cell to chemotherapeutic drugs]. 1193 9

We report the results of a dose-intense chemotherapy regimen designed to rapidly induce remissions in patients with advanced multiple myeloma (MM). Patients received VAD for 3-6 cycles depending on response kinetics. This was followed by three sequential cycles of cyclophosphamide (CTX) at 3 g/m2 every 15 days with G-CSF support. 71% of these patients had stage IIIa, 23% had renal failure. The median age was 58, median beta-2 microglobulin 4.6 and median albumin was 3.5, indicating poor prognosis. Of 35 patients, 66% achieved a complete response (CR) (SWOG). Six patients (18%) had a partial response. Fifty percent of the patients with renal failure recovered their kidney function. High-dose CTX contributed to tumor-mass reduction particularly in patients presenting with high-tumor burden. Tumor-mass reduction following three pulses of dexamethasone (4 days each) is significantly higher than with one pulse (p < 0.005). While high beta-2 microglobulin and LDH levels (p < 0.05) were associated with poor outcome, patients who responded faster to chemotherapy had a longer survival (p = 0.005). We conclude that this regimen is safe and effective. A rapid response may be useful in selecting patients who may benefit from further high dose chemotherapy and stem cell support.
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PMID:Impact of early response to sequential high-dose chemotherapy on outcome of patients with advanced myeloma and poor prognostic features. 1200 66

A number of recent preclinical studies have sparked interest in the concept of exploiting conventional chemotherapeutic drugs as antiangiogenics. Such antiangiogenic activity is achieved or optimized by metronomic-dosing protocols in which the drug is given at comparatively low doses using a frequent schedule of administration (e.g., once to three times per week) with no breaks, particularly when combined with an endothelial cell-specific antiangiogenic drug. The use of p.o. chemotherapeutic drugs is particularly suitable for this type of treatment strategy. We tested one such drug, cyclophosphamide (CTX), in a protocol wherein the drug was administered to mice at low doses, of approximately 10-40 mg/kg on a daily basis through the drinking water. CTX is typically given p.o. to patients, but it has almost always been injected when treating preclinical mouse tumor models. We found p.o. CTX to be a safe and convenient treatment with significant antitumor efficacy. Growth delays were observed for human orthotopic breast or ectopic colon cancer xenografts in nude or SCID mice. Established PC3 human prostate tumor xenografts could be induced to almost fully regress, remaining virtually nonpalpable for > or =2 months of continuous therapy, after which tumors began to grow progressively. These re-emergent tumors were not found to be drug resistant when tested in new hosts, using the same treatment protocol. Regression of spontaneously arising, late-stage pancreatic islet cell carcinomas in Rip Tag transgenic mice was also observed. The effects of continuous p.o. CTX treatment were enhanced significantly in an orthotopic, metastatic breast cancer xenograft model when used in combination with an antivascular endothelial growth factor receptor-2 blocking antibody. Maximum tolerated dose levels established for other mouse strains proved highly toxic to SCID mice, whereas daily p.o. low-dose regimens of CTX were well tolerated. Taken together, the results demonstrate the feasibility of delivering CTX in a p.o. metronomic chemotherapy regimen, which proved safe, reasonably efficacious, and potentially applicable to chronic treatment. Such a regimen may be particularly well suited for integration with antiangiogenic drugs.
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PMID:Antitumor effects in mice of low-dose (metronomic) cyclophosphamide administered continuously through the drinking water. 1201 44

Waldenstrom's macroglobulinemia (WM) is an uncommon lymphoproliferative disease which remains incurable with current treatment protocols. We have previously established a permanent WM cell line, WSU-WM, which grows as a xenograft in severe combined immune deficient (SCID) mice. In this study, we investigated the antitumor effects of Rituximab (RTX), Cyclophosphamide (CTX), Dexamethasone (DEX) [RCD]-Regimen in vivo WSU-WM SCID xenograft and in a patient with WM. For the pre-clinical efficacy study, WSU-WM-bearing SCID mice were randomly assigned to receive RTX (150 mg/kg/inj, i.v., QDX5), CTX (90 mg/kg/inj, s.c. QDX5) as single agents or diluent. The combination group received RTX at 150 mg/kg/inj, QDX5; CTX at 150 mg/kg/inj, QODX3 and DEX at 1.0 mg/kg/inj, i.v., QDX5. Tumor growth inhibition (T/C), tumor growth delay (T - C), and log10 kill (net) for RTX and CTX were 24.5%, 37 days, 5.52 and 88%, 0.0 days, 0.0log10 kill, respectively. No cures were observed with either agent; however, all mice (6/6, with bilateral tumors) were cured when treated with RCD-regimen. A 57-year-old patient with relapsed WM was treated with the RCD-regimen and showed an excellent partial remission for seven months. The patient tolerated the treatment very well, the hemoglobin improved dramatically, platelets remained stable, the IgM level normalized and there was only minimal involvement of bone marrow. Based on these results, the RCD regimen is effective against WM and its activity should be further evaluated in clinical trials.
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PMID:Rituximab, Cyclophosphamide, Dexamethasone (RCD) regimen induces cure in WSU-WM xenograft model and a partial remission in previously treated Waldenstrom's macroglobulinemia patient. 1244 11

Abalone polysaccharide (AP) was extracted from Haliotis discushannai Ino. The combined effects of AP and CTX against tumor-bearing mice were investigated. The results showed that AP could markedly promote the inhibition effects of CTX on S180 and HepA tumor, enhance protection against leukocytopenia, decrease of spleen and thymus weight and hemolysin in serum, and bone marrow supression induced by CTX.
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PMID:[Synergy and attenuation of cyclophosphamidum (CTX) activities by abalone polysaccharide]. 1257 6

To explore the antitumor activities of KRN7000 in a NS-1 myeloma-bearing mice and the underlying mechanisms, cytotoxic activities of the spleen cells treated with KRN7000 in vivo and in vitro were examined with Yac-1 (a NK-sensitive cell line) and NS-1 (a NK-insensitive cell line) as the targeted cells. The life span of NS-1 myeloma-bearing mice was observed after treating with KRN7000 and combined with cyclophosphamide (CTX). Furthermore, toxicities of KRN7000 administration on liver and kidney were evaluated. The results showed that KRN7000 enhanced NK cytotoxic activities of spleen cells. Around 20% of NS-1-bearing mice survived after KRN7000 administration and the survival rate reached up to 80% of NS-1-bearing mice when KRN7000 was used in combination with CTX at a dose of 100 mg/kg (P < 0.005). KRN7000, at a dose of 100 micro g/kg, had no toxic effects on liver and kidney. These findings suggest that KRN7000 might be a promosing agent in tumor immunotherapy.
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PMID:[Antitumor Activities of KRN7000 in NS-1 Myeloma-Bearing Mice] 1257 76

Ifosfamide (IF) and cyclophosphamide (CTX) are chemotherapeutic agents frequently used in the treatment of human malignancies. These drugs can exhibit a bimodal mechanism of antitumor action with cytotoxic and immunomodulatory effects when associated with adoptive immunotherapy. In human peripheral blood lymphocytes, IF irreversibly inhibits the proliferative response to interleukin-2 in a dose-dependent manner and may also induce the phosphorylation of HSP27 by depleting glutathione. CTX promotes discrete cytokine profiles upregulating the expansion of Th1 cells, and this may be important to increase cellular immune response. The data presented in this report indicate that treatment regimens of CTX and IF may be used according to the tumor immunogenicity.
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PMID:Ifosfamide and cyclophosphamide: effects on immunosurveillance. 1458 42

Immunotherapy could be combined with conventional chemotherapeutic modalities aimed at reducing tumor burden. Such combination therapy may be most useful when "metronomic" doses of antineoplastic drugs are used, thereby potentially avoiding some of the immunosuppressive effects of these drugs. Recent studies have shown that some conventional antineoplastic drugs can be exploited for antiangiogenic capacities, a strategy that requires drugs to be administered at regular intervals. We therefore investigated whether such metronomic therapy with the alkylating agent cyclophosphamide (CTX) could be effectively combined with immunotherapy eliciting tumor-reactive CTLs. An immunization protocol using injection of recombinant DNA followed by injection of recombinant modified vaccinia virus Ankara strain was used to initiate a specific CTL response in mice capable of providing resistance to challenge with the murine melanoma B16.F10. Combining this immunotherapeutic regime with metronomic delivery of CTX resulted in antitumor activity that was dramatically enhanced over either treatment administered alone and was also significantly greater than combining immunotherapy with CTX administered by a maximum tolerated dose regime. Whereas both metronomic and maximum tolerated dose delivery of CTX did cause deletion of proliferating tumor-specific CTLs in the blood, this deletion occurred with slower kinetics with the metronomic schedule. Further analysis showed that metronomic CTX treatment did not delete cells with low expression of CD43, a "memory" phenotype, and that these cells maintained potent restimulatory capacity. The combination of immunotherapy and metronomic CTX therapy may be well suited to clinical management of cancer.
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PMID:Synergistic effect of metronomic dosing of cyclophosphamide combined with specific antitumor immunotherapy in a murine melanoma model. 1467 3


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