Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0699790 (colon cancer)
 28,837 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of somatostatin analogue RC-160 on the growth of hepatic metastases of colon cancer was investigated in rats using magnetic resonance imaging. Experimental liver metastatic tumors were established in syngeneic BDIX rats after intrasplenic injection of DHD/K12 colon adenocarcinoma cells. Each rat with implanted liver tumors received s.c. injections of somatostatin analogue RC-160 (50 micrograms/kg) or the vehicle (control) twice a day for 4 weeks, starting 3 weeks after tumor inoculation. During the treatment with RC-160, the growth of liver tumors was studied quantitatively by measuring liver tumor volumes in vivo with magnetic resonance imaging at intervals of 7 days. Chronic administration of RC-160 inhibited the growth of hepatic metastases of colon cancer in rats. Significant inhibition of liver tumor growth in RC-160-treated rats was observed throughout the treatment. The final liver tumor volume in the treated rats was decreased by 56.1% as compared to the controls. The treatment with RC-160 reduced the percentage increase in liver tumor volume from 1575 +/- 674% (mean +/- SEM) for the control to 1034 +/- 727% in the treated group. The tumor volume doubling time in treated rats was 3.7 days longer than the controls. The liver tumor growth delay time was 15.1 days. At the end of the treatment, the incidence of ascites and the weights of tumorous livers were also decreased by RC-160 treatment. Administration of RC-160 prolonged the median survival time by 13 days in treated rats. In cell cultures, significant inhibitory effects of somatostatin-14 and RC-160 on the growth of DHD/K12 colon cancer cells were determined by MTT assay and [3H]-thymidine incorporation assay, indicating direct effects of these peptides on the growth of colon cancer cells in vitro. These data suggest that administration of RC-160 could inhibit the growth of colon cancer and their hepatic metastases in rats. Somatostatin analogue RC-160 might be considered as a potential new agent for the treatment of patients with hepatic metastases of colorectal cancers.
 ...
PMID:Inhibitory effect of somatostatin analogue RC-160 on the growth of hepatic metastases of colon cancer in rats: a study with magnetic resonance imaging. 135 23

Precise estimation of the volume and growth rate of hepatic metastases would represent an important step forward not only in clinical oncology but also for the evaluation of experimental treatments in animal models. In the present study, an original method of volumetry of hepatic metastatic tumors in vivo has been tested in rats using magnetic resonance imaging (MRI). Three different hepatic tumor models mimicking liver metastases were established in syngeneic BDIX rats by injection of DHD/K12 rat colon cancer cells either directly under the liver capsule or via the portal system. The liver tumor volumes were estimated in vivo by using MR imaging of the liver and summing the individual tumor volumes in the sequential MR liver sections. The values of the tumor volumes measured by MRI were compared with those determined by a classical method of water displacement in vitro after killing the animals and excising the tumors. At 3 weeks after tumor implantation, liver tumors as small as 1 mm in diameter could be detected by MRI. The difference between the tumor volumes estimated by MRI in vivo and those measured by water displacement in vitro was 9% for single liver tumors and 16% for multiple liver tumors. Close correlation between the values of the tumor volumes measured by MRI and those determined by water displacement was observed in solitary liver tumors (r = 0.985, p less than 0.01) as well as in multiple liver tumors (r = 0.985, p less than 0.01), indicating the high accuracy of MRI volumetry for liver tumors. Estimation of the liver tumor volumes by MRI in the same animals at successive time intervals made it possible to construct tumor growth curves and to calculate tumor growth parameters. These data suggest that MRI volumetry represents an effective means of evaluating the efficacy of experimental treatments in small animals and may have potentially important applications in clinical patients.
 ...
PMID:Quantitative study of the growth of experimental hepatic tumors in rats by using magnetic resonance imaging. 160 27

The effect of somatostatin analogue RC-160 on the growth of DHD/K12 rat colon cancer has been investigated in vivo as well as in vitro. Twenty syngeneic BDIX rats with s.c. implanted tumors were divided randomly into 2 groups. The rats from each group received a daily s.c. injection of either RC-160 (100 micrograms/kg/day) or injection vehicle as control for 37 days starting from the day of tumor inoculation. Tumor volumes were measured every 3-4 days. At the end of the treatment, the mean tumor volume was 504.5 +/- 97.0 mm3 in the control group and 177.8 +/- 60.5 mm3 in the RC-160 treated group (p less than 0.01). The tumor volume doubling time was calculated to be 11 days in the control group and 13.5 days in the RC-160 group, respectively. The tumor growth delay time was 18 days. Using bromodeoxyuridine labelling in vivo, the mean labelling index in the tumors was decreased by 35% (p less than 0.01) after RC-160 treatment. Total protein and total DNA contents in the tumors were decreased by 70.1% (p less than 0.05) and 68.7% (p less than 0.05), respectively. The data indicate that somatostatin analogue RC-160 inhibits the growth of DHD/K12 colon cancer in vivo. In 2 studies in vitro, DHD/K12 cells were cultured for 72 hr with RC-160 and natural somatostatin-14 (S-S-14) at concentrations ranging from 62.5 ng/ml to 2,000 ng/ml. Tumor-cell growth was measured spectrophotometrically by the crystal violet staining assay. No direct effect on tumor cell growth in vitro was observed with either RC-160 or S-S-14, possibly because of the loss of somatostatin receptors in previous passages of the DHD/K12 cell line.
 ...
PMID:Somatostatin analogue RC-160 inhibits the growth of transplanted colon cancer in rats. 167 6

Quinine, the widely used antimalaria agent, was found to increase the cytotoxicity of epideoxorubicin (epiDXR) in resistant DHD/K12 rat colon cancer cells in vitro. Quinine appeared as slightly less effective than quinidine or verapamil for anthracycline potentiation but its weaker cardiotoxicity could counterbalance this disadvantage in vivo. Serum from six patients treated by conventional doses of quinine (25-30 mg kg-1 day-1) was demonstrated to enhance the accumulation of epiDXR in DHD/K12 cells as judged by fluorescence microscopy and HPLC assay (1.6 to 6-fold compared with control serum). In this patients quinine concentrations in serum ranged from 4.4 to 10.1 micrograms ml-1. Our results suggest that quinine could be safely used as anthracycline resistance modifier in clinical practice.
 ...
PMID:Potential usefulness of quinine to circumvent the anthracycline resistance in clinical practice. 220 48

Two colon cancer cell lines, HT-29 (human) and DHD/K12/TRb (rat), were grown as monolayer cultures to various confluence degrees. The cytotoxic efficacies of doxorubicin and 4'-deoxydoxorubicin, evaluated by a survival assay, and the nuclear drug concentrations, measured by microspectrofluorometry, were shown to progressively decrease with the augmentation of confluence. This confluence dependent resistance (CDR) to anthracyclines was demonstrated independent of the multidrug resistance drug efflux mechanism. The cellular uptake of three compounds (sodium [51Cr]chromate, D-[14C]alanine, L-[14C]glucose) known to passively diffuse across the cell membrane as anthracyclines do was also reduced in confluent cells. After trypsin cell detachment, the kinetics of reversion of the sodium [51Cr]chromate uptake decrease and that of CDR were similar. Therefore, CDR may be attributed to a reduction of anthracycline cell intake due to a general alteration of passive diffusion across the cell membrane. However, CDR is only partly explained by this phenomenon since a reduced sensitivity of confluent cells was observed compared with nonconfluent cells for a similar amount of drug in their nuclei. CDR could explain the high resistance to anthracyclines of some solid tumors, such as colon tumors, in which cancer cells are tightly aggregated.
 ...
PMID:Mechanisms of resistance of confluent human and rat colon cancer cells to anthracyclines: alteration of drug passive diffusion. 220 25

We demonstrated previously that amiodarone is able to circumvent in vitro the inherent resistance to anthracyclines of the DHD/K12 rat colon cancer cell line. We have now determined in the rat the amiodarone seric concentrations required to enhance the in vitro cytotoxicity of 4'-deoxydoxorubicin (deoDX) against DHD/K12 cells. A maximal deoDX potentiation was obtained in vitro when anthracycline was diluted in the serum of rats receiving at least 75 mg/kg of intravenous amiodarone resulting in seric concentrations of more than 40 micrograms/ml. In patients treated with amiodarone, the mean serum concentrations were 0.9 +/- 0.1 microgram/ml after an one month's oral administration of 200 mg/day, 2.2 +/- 1.0 micrograms/ml after a 24 hr continuous infusion of 300 to 900 mg/day and 5.4 +/- 1.1 micrograms/ml after a brief 3 hrs infusion of 450 mg amiodarone. Such amiodarone concentrations in human serum are much lower than those necessary to produce a significant anthracycline potentiation. In rats receiving amiodarone at a maximal tolerated dose (100 mg/kg) minutes before the injection of 10 mg/kg doxorubicin (DX), we observed an increased accumulation of the anthracycline in the liver and kidney compared to rats receiving DX alone. The DX content was not modified by amiodarone in the other organs studied (heart, lung, spleen and pancreas). An amiodarone pretreatment accelerated the death of rats receiving 5 or 10 mg/kg DX did not provoke lethality for a lower dose of 2.5 mg/kg DX. The very high doses required and the risk of increased toxicity seem to preclude the use of amiodarone for the modulation of anthracycline resistance in cancer patients.
 ...
PMID:Serum concentrations of amiodarone required for an in vivo modulation of anthracycline resistance. 262 17

A simple model for liver metastasis from colon cancer resulted from the intraportal injection of 2 x 10(7) highly tumorigenic DHD/K12/PROb cells into syngeneic BDIX rats. Early detection and development of cancer invasion were studied by conventional microscopy and immunoenzymatic staining using a specific monoclonal antibody. Metastases developed either from isolated cancer cells early disseminated in sinusoid network or from intraportal microthrombi. An intense immune reaction developed until day 15 after injection but decreased and disappeared at the latest stages of evolution.
 ...
PMID:Use of a specific monoclonal antibody for studying the liver metastatic invasion of a rat colon cancer. 297 48

Liver metastases were produced in syngeneic BD IX rats by intraportal injection of colon cancer cell aggregates. The cells originated from the DHD/K12 cell line, derived from a 1,2-dimethylhydrazine (CAS: 540-73-8)-induced colon adenocarcinoma in BD IX rats. The animals received either cyclosporine A (CSA) or the excipients alone (control) through daily gastric intubation during 6 weeks. Multiple and very large hepatic metastases were observed early in 100% of the CSA-treated rats. The mean tumor volume was approximately 2,000 times higher in the CSA-treated group than in the controls (P less than .01). Survival time in the CSA-treated group was shortened (P less than .01) by generalized metastatic disease. Easy production of metastasis from colon cancer in 100% of the animals and precise estimation of tumor volume may prove useful for future therapeutic studies of secondary hepatic disease.
 ...
PMID:Quantitative study of liver metastases from colon cancer in rats after treatment with cyclosporine A. 345 15

In a rat colon carcinoma model (DHD/K 12-PROb), two varieties of cells were selected after in vivo passaging: PROb h2, representing a liver-specific variant and PROb Mp1, representing a lung metastatic variant and producing liver and lung metastases after intracecal injection (one out of four). The study of the adhesion and the growth of cells in vitro for contact hepatocytes and/or endothelial cells gave the following results: (1) except for PROb Mp1, tumor cell growth was independent of the cell support; (2) adhesion of PROb Mp1 to endothelial cells was lower between 30 and 120 min, whereas adhesion of PROb h2 to hepatocytes was greater and durable after 60 min (P < or = 0.05). These results suggest that the formation of liver metastases in a dynamic process and that tumor cells have a great ability to adhere to hepatocytes. Improved by serial passaging in vivo, our intracecal model might be useful for studying many aspects of the pathogenesis of colon cancer metastasis, while concurrent in vitro studies of the adhesion and growth ability of cells might be a useful indicator for assessing the in vivo behavior.
 ...
PMID:Experimental model of liver metastases: adhesion and growth of cells on contact with endothelial or hepatocyte cell monolayer cultures. 820 39

In vivo labelling with bromodeoxyuridine (BrdU) was compared with 3H-thymidine (3HTdR) labelling for the study of cell proliferation in normal colon epithelium and in colon cancer tissue. Twenty-four BDIX rats with implanted subcutaneous tumors of DHD/K12 colon cancer cells were subdivided into 3 groups. Each rat received an intraperitoneal injection of either 5-bromo-2'deoxyuridine (50 mg/kg), or 3H-thymidine (1mCi/kg) or both precursors (double labelling). Immunoperoxidase staining with a monoclonal antibody to BrdU, or autoradiography were used. In the colonic crypts, similar patterns of spatial distributions of the labelled colonic epithelial cells were observed after each kind of labelling. The mean labelling indices (LI) by BrdU and by 3HTdR were similar in the normal colon as well as in the implanted tumors. The validity of BrdU labelling in vivo was further investigated by using BrdU+3HTdR double labelling technique. In the colonic crypts, the total BrdU labelled colonic epithelial cells were 11.85%, whereas the total 3HTdR labelled cells were 11.99% (p > 0.05). In the implanted tumors of colon cancer, the total BrdU and 3HTdR labelled cells accounted for 19.40% and 20.10% respectively of the colon cancer cells (p > 0.05). There was a close correlation between BrdU LI and 3HTdR LI in colonic epithelial cells (r = 0.99, p < 0.0001) as well as in colon cancer cells (r = 0.97, p < 0.001). There data indicate that the labelling index of BrdU is equivalent to that of 3HTdR not only in normal colonic epithelium but also in colon cancer. BrdU may thus be used for measuring proliferation parameters in cancer tissues.
 ...
PMID:Comparison of the classical autoradiographic and the immunohistochemical methods with BrdU for measuring proliferation parameters in colon cancer. 831 5


1 2 3 Next >>