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Human Colorectal Carcinoma: Patterns of Sensitivity to Chemotherapeutic Agents in the Human Tumor Stem Cell Assay
ONCOLOGY AND CHEMOTHERAPY
presentation. This fact is important since the treatment of these 2 tumors differs considerably. Nerve tissue contains 2 enolase forms: neuron specific enolase found in nerve cells and nonneuronal enolase present in glial cells. Neuron specific enolase usually appears to be restricted to cells of neuronal origin. Relative neuron specific enolase activities were measured in a series of biopsies from neuroblastoma and Wilms tumor cases. The highest relative neuron specific enolase activities were found in neuroblastoma (28 to 62.5 per cent of the total enolase activity), while Wilms tumors contained only 1. 7 to 4.5 per cent. To be sure neuron specific enolase is not found in most tumors, other tumors having been analyzed. Neuron specific enolase was found to be elevated only in patients with pheochromocytomas and with the Zollinger-Ellison syndrome. This fact indicates that neuron specific enolase is restricted to tumor cells of neuronal origin. Thus, this assay has promise in helping to separate poorly differentiated Wilms and neuroblastoma cases. H.M.S. 1 figure, 3 tables, 9 references
Kinetic Properties Of Thymidine Kinase From the Cytosol of a Rat Colon Adenocarcinoma
E. P. KOWAL AND G. MARKUS, Department of Biochemistry, Roswell Park Division of the Graduate School of the State University of New York at Buffalo, and the Department of Experimental Biology, Roswell Park Memorial Institute, Buffalo, New York J. Med., 13: 97-120, 1982 The purpose of this investigation was to measure the kinetics of thymidine kinase using concentrations of magnesium adenosine triphosphate and so forth, calculated on the basis of experimentally determined dissociation constants for these complexes, and using these data to determine the type of kinetic mechanism and the order of substrate addition for the cytosol enzyme. These authors present analysis of the kinetics of thymidine kinase (EC 2.7.1.7.5) from the cytosol of a rat colon adenocarcinoma, which was purified partially by affinity chromatography. The initial velocity was analyzed as a function of the concentrations of thymidine and magnesium adenosine triphosphate complex, while the latter concentration was calculated using the association constant for the complex that was determined experimentally under the approximate reaction conditions for the kinase. Normal Michaelis-Menten kinetics were observed, except for substrate inhibition at high magnesium adenosine triphosphate concentrations. The Km for thymidine was 2.5 µ,M. and that for magnesium adenosine triphosphate was 7.3 µ,M. An intersecting pattern of straight lines was observed for the Lineweaver-Burk plot for each substrate in the presence of different constant concentrations of the other, indicating a sequential mechanism. Product inhibition studies revealed that a random addition sequential mechanism was the case. It also was found by kinetic analysis that free adenosine triphosphate followed by magnesium++ ion could add to the enzyme in place of magnesium adenosine triphosphate in the kinetic mechanism. Binding of magnesium++ ion first, followed by adenosine triphosphate did not occur. An inhibitor of thymidine kinase (magnesium-dTTP) converted the normally straight Lineweaver-Burk plot for magnesium adenosine triphosphate to concave upward, indicating a sigmoidal saturation curve. The inhibition curve for this inhibitor at saturating concentrations of substrates also was sigmoidal. Such data are consistent
445
with the hypothesis that magnesium-dTTP is an allosteric inhibitor of thymidine kinase. E.D. W. 8 figures, 39 references
Human Colorectal Carcinoma: Patterns of Sensitivity to Chemotherapeutic Agents in the Human Tumor Stem Cell Assay M. V. AGREZ, J. S. KOVACH, R. V. BEART, JR., J. RUBIN, C. G. MoERTEL AND M. M. LIEBER, Departments of General Surgery (Colorectal Surgery), Oncology, and Urology, Mayo Clinic, Rochester, Minnesota J. Surg. Oncol., 20: 187-191 (July) 1982 Approximately 50 per cent of the patients who undergo surgical resection of carcinoma of the colon or rectum die of the disease within 5 years of the diagnosis. There is obvious need for adjuvant chemotherapy. However, no form of effective cytotoxic chemotherapy is available for colorectal carcinoma at this time. Search for new chemotherapeutic agent(s) can be facilitated by the use of human tumor stem cell assay, which provides a method for studying the drug sensitivity characteristics of the individual neoplasms in vitro on the basis of the extent of inhibition of colony formation by the tumor cells. Several reports have suggested a direct relationship between in vitro drug sensitivity of tumor cells by human tumor stem cell assay and the in vitro responsiveness of the tumor to drug therapy. The authors report the results of their study on the patterns of sensitivity of colorectal carcinoma to chemotherapeutic agents using human tumor stem cell assay. The human tumor stem cell assay was used to study the sensitivity characteristics of 103 primary and metastatic colorectal carcinomas. Bacterial and/ or fungal contamination made 34 cultures (33 per cent) inevaluable. Of the 69 evaluable cultures only 18 (26 per cent) showed typical colony formation in the culture medium. The ability of the tumor cells to form colonies had no relationship with the clinicopathologic stage of the neoplasm, the histologic grade of the tumor, the technique used to disperse the solid tumor into single cells or cell viability before culturing. The chemotherapeutic sensitivity tests were conducted only on 18 tumors that formed colonies. The majority of those tumors were resistant to the chemotherapeutic agents. However, some of them were sensitive to multiple drugs. The authors conclude that for the treatment of colorectal carcinoma the use of the human tumor stem cell assay may enable one to select chemotherapeutic agent(s) more rationally. Human tumor stem cell assays also may help in the search for newer cytotoxic drugs. N.S.D. 3 tables, 13 references
Serum Lactate Dehydrogenase Isoenzyme 1 in Patients With Advanced Testicular Cancer F. LIU, H. A. FRITSCHE, J.M. TRUJILLO AND M. L. SAMUELS, Departments of Laboratory Medicine and Medicine, The University of Texas, M.D. Anderson Hospital and Tumor Institute, Houston, Texas Amer. J. Clin. Path., 78: 178-183 (Aug.) 1982 Abnormal levels of serum lactic dehydrogenase-1 activity were observed in 81 per cent (34 of 42) of the patients with stage III germ cell tumors of the testis. The frequency of lactic dehydrogenase-1 elevation correlated well with the extent of the disease and response to therapy. Lactic dehydrogenase-1
presentation. This fact is important since the treatment of these 2 tumors differs considerably. Nerve tissue contains 2 enolase forms: neuron specific enolase found in nerve cells and nonneuronal enolase present in glial cells. Neuron specific enolase usually appears to be restricted to cells of neuronal origin. Relative neuron specific enolase activities were measured in a series of biopsies from neuroblastoma and Wilms tumor cases. The highest relative neuron specific enolase activities were found in neuroblastoma (28 to 62.5 per cent of the total enolase activity), while Wilms tumors contained only 1. 7 to 4.5 per cent. To be sure neuron specific enolase is not found in most tumors, other tumors having been analyzed. Neuron specific enolase was found to be elevated only in patients with pheochromocytomas and with the Zollinger-Ellison syndrome. This fact indicates that neuron specific enolase is restricted to tumor cells of neuronal origin. Thus, this assay has promise in helping to separate poorly differentiated Wilms and neuroblastoma cases. H.M.S. 1 figure, 3 tables, 9 references
Kinetic Properties Of Thymidine Kinase From the Cytosol of a Rat Colon Adenocarcinoma
E. P. KOWAL AND G. MARKUS, Department of Biochemistry, Roswell Park Division of the Graduate School of the State University of New York at Buffalo, and the Department of Experimental Biology, Roswell Park Memorial Institute, Buffalo, New York J. Med., 13: 97-120, 1982 The purpose of this investigation was to measure the kinetics of thymidine kinase using concentrations of magnesium adenosine triphosphate and so forth, calculated on the basis of experimentally determined dissociation constants for these complexes, and using these data to determine the type of kinetic mechanism and the order of substrate addition for the cytosol enzyme. These authors present analysis of the kinetics of thymidine kinase (EC 2.7.1.7.5) from the cytosol of a rat colon adenocarcinoma, which was purified partially by affinity chromatography. The initial velocity was analyzed as a function of the concentrations of thymidine and magnesium adenosine triphosphate complex, while the latter concentration was calculated using the association constant for the complex that was determined experimentally under the approximate reaction conditions for the kinase. Normal Michaelis-Menten kinetics were observed, except for substrate inhibition at high magnesium adenosine triphosphate concentrations. The Km for thymidine was 2.5 µ,M. and that for magnesium adenosine triphosphate was 7.3 µ,M. An intersecting pattern of straight lines was observed for the Lineweaver-Burk plot for each substrate in the presence of different constant concentrations of the other, indicating a sequential mechanism. Product inhibition studies revealed that a random addition sequential mechanism was the case. It also was found by kinetic analysis that free adenosine triphosphate followed by magnesium++ ion could add to the enzyme in place of magnesium adenosine triphosphate in the kinetic mechanism. Binding of magnesium++ ion first, followed by adenosine triphosphate did not occur. An inhibitor of thymidine kinase (magnesium-dTTP) converted the normally straight Lineweaver-Burk plot for magnesium adenosine triphosphate to concave upward, indicating a sigmoidal saturation curve. The inhibition curve for this inhibitor at saturating concentrations of substrates also was sigmoidal. Such data are consistent
445
with the hypothesis that magnesium-dTTP is an allosteric inhibitor of thymidine kinase. E.D. W. 8 figures, 39 references
Human Colorectal Carcinoma: Patterns of Sensitivity to Chemotherapeutic Agents in the Human Tumor Stem Cell Assay M. V. AGREZ, J. S. KOVACH, R. V. BEART, JR., J. RUBIN, C. G. MoERTEL AND M. M. LIEBER, Departments of General Surgery (Colorectal Surgery), Oncology, and Urology, Mayo Clinic, Rochester, Minnesota J. Surg. Oncol., 20: 187-191 (July) 1982 Approximately 50 per cent of the patients who undergo surgical resection of carcinoma of the colon or rectum die of the disease within 5 years of the diagnosis. There is obvious need for adjuvant chemotherapy. However, no form of effective cytotoxic chemotherapy is available for colorectal carcinoma at this time. Search for new chemotherapeutic agent(s) can be facilitated by the use of human tumor stem cell assay, which provides a method for studying the drug sensitivity characteristics of the individual neoplasms in vitro on the basis of the extent of inhibition of colony formation by the tumor cells. Several reports have suggested a direct relationship between in vitro drug sensitivity of tumor cells by human tumor stem cell assay and the in vitro responsiveness of the tumor to drug therapy. The authors report the results of their study on the patterns of sensitivity of colorectal carcinoma to chemotherapeutic agents using human tumor stem cell assay. The human tumor stem cell assay was used to study the sensitivity characteristics of 103 primary and metastatic colorectal carcinomas. Bacterial and/ or fungal contamination made 34 cultures (33 per cent) inevaluable. Of the 69 evaluable cultures only 18 (26 per cent) showed typical colony formation in the culture medium. The ability of the tumor cells to form colonies had no relationship with the clinicopathologic stage of the neoplasm, the histologic grade of the tumor, the technique used to disperse the solid tumor into single cells or cell viability before culturing. The chemotherapeutic sensitivity tests were conducted only on 18 tumors that formed colonies. The majority of those tumors were resistant to the chemotherapeutic agents. However, some of them were sensitive to multiple drugs. The authors conclude that for the treatment of colorectal carcinoma the use of the human tumor stem cell assay may enable one to select chemotherapeutic agent(s) more rationally. Human tumor stem cell assays also may help in the search for newer cytotoxic drugs. N.S.D. 3 tables, 13 references
Serum Lactate Dehydrogenase Isoenzyme 1 in Patients With Advanced Testicular Cancer F. LIU, H. A. FRITSCHE, J.M. TRUJILLO AND M. L. SAMUELS, Departments of Laboratory Medicine and Medicine, The University of Texas, M.D. Anderson Hospital and Tumor Institute, Houston, Texas Amer. J. Clin. Path., 78: 178-183 (Aug.) 1982 Abnormal levels of serum lactic dehydrogenase-1 activity were observed in 81 per cent (34 of 42) of the patients with stage III germ cell tumors of the testis. The frequency of lactic dehydrogenase-1 elevation correlated well with the extent of the disease and response to therapy. Lactic dehydrogenase-1