Abstract
We utilized the presence of hepatic receptors for galactose-terminal glycoproteins to achieve specific rescue of differentiated hepatocytes from methotrexate toxicity. This was accomplished by administration of a conjugate formed by covalent coupling of the methotrexate antagonist, folinic acid (leucovorin), to galactose-terminating (desialylated) bovine fetuin. Two cultured hepatocyte-derived cell lines were chosen to test rescue from methotrexate toxicity: Hep G2 cells are capable of receptor-mediated endocytosis of galactose-terminating glycoproteins; PLC/PRF/5 cells are not. In the presence of methotrexate alone, both cells lines were reduced in number to 20% of control populations by day 5. Growth rates of both lines returned to normal when free folinic acid was added to the medium containing methotrexate. When asialofetuin-folinic acid conjugate was given to both cell lines in the presence of methotrexate, Hep G2 cells doubled their numbers by day 4 and reached control (without methotrexate) populations by day 8. However, PLC/PRF/5 cells failed to respond to administered asialofetuin-folinic acid conjugate under identical conditions, and the growth curve was the same as that for cells which received methotrexate alone. Conjugates of asialofetuin bound to folic acid (folate derivative requiring dihydrofolate reductase activity for conversion to an active metabolite) and fetuin (non-galactose-terminal glycoprotein) linked to folinic acid also were made for control studies. These conjugates failed to rescue either cell line.
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Selected References
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- Aden D. P., Fogel A., Plotkin S., Damjanov I., Knowles B. B. Controlled synthesis of HBsAg in a differentiated human liver carcinoma-derived cell line. Nature. 1979 Dec 6;282(5739):615–616. doi: 10.1038/282615a0. [DOI] [PubMed] [Google Scholar]
- BOYSE E. A., OLD L. J., CHOUROULINKOV I. CYTOTOXIC TEST FOR DEMONSTRATION OF MOUSE ANTIBODY. Methods Med Res. 1964;10:39–47. [PubMed] [Google Scholar]
- BURCHENAL J. H. The clinical management of leukemias. Cancer Res. 1954 Oct;14(9):615–624. [PubMed] [Google Scholar]
- BURKITT D., HUTT M. S., WRIGHT D. H. THE AFRICAN LYMPHOMA: PRELIMINARY OBSERVATIONS ON RESPONSE TO THERAPY. Cancer. 1965 Apr;18:399–410. doi: 10.1002/1097-0142(196504)18:4<399::aid-cncr2820180402>3.0.co;2-g. [DOI] [PubMed] [Google Scholar]
- Beyer E. C., Zweig S. E., Barondes S. H. Two lactose binding lectins from chicken tissues. Purified lectin from intestine is different from those in liver and muscle. J Biol Chem. 1980 May 10;255(9):4236–4239. [PubMed] [Google Scholar]
- Cawley D. B., Simpson D. L., Herschman H. R. Asialoglycoprotein receptor mediates the toxic effects of an asialofetuin-diphtheria toxin fragment A conjugate on cultured rat hepatocytes. Proc Natl Acad Sci U S A. 1981 Jun;78(6):3383–3387. doi: 10.1073/pnas.78.6.3383. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Falkson G. Therapeutic approaches to hepatoma. Cancer Treat Rev. 1975 Mar;2(1):73–76. doi: 10.1016/s0305-7372(75)80016-8. [DOI] [PubMed] [Google Scholar]
- GREENWOOD F. C., HUNTER W. M., GLOVER J. S. THE PREPARATION OF I-131-LABELLED HUMAN GROWTH HORMONE OF HIGH SPECIFIC RADIOACTIVITY. Biochem J. 1963 Oct;89:114–123. doi: 10.1042/bj0890114. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gregoriadis G., Morell A. G., Sternlieb I., Scheinberg I. H. Catabolism of desialylated ceruloplasmin in the liver. J Biol Chem. 1970 Nov 10;245(21):5833–5837. [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- ROSS G. T., GOLDSTEIN D. P., HERTZ R., LIPSETT M. B., ODELL W. D. SEQUENTIAL USE OF METHOTREXATE AND ACTINOMYCIN D IN THE TREATMENT OF METASTATIC CHORIOCARCINOMA AND RELATED TROPHOBLASTIC DISEASES IN WOMEN. Am J Obstet Gynecol. 1965 Sep 15;93:223–229. doi: 10.1016/0002-9378(65)90661-7. [DOI] [PubMed] [Google Scholar]
- Regoeczi E., Chindemi P. A., Hatton M. W., Berry L. R. Galactose-specific elimination of human asialotransferrin by the bone marrow in the rabbit. Arch Biochem Biophys. 1980 Nov;205(1):76–84. doi: 10.1016/0003-9861(80)90085-5. [DOI] [PubMed] [Google Scholar]
- SPIRO R. G. Studies on the monosaccharide sequence of the serum glycoprotein fetuin. J Biol Chem. 1962 Mar;237:646–652. [PubMed] [Google Scholar]
- Schwartz A. L., Fridovich S. E., Knowles B. B., Lodish H. F. Characterization of the asialoglycoprotein receptor in a continuous hepatoma line. J Biol Chem. 1981 Sep 10;256(17):8878–8881. [PubMed] [Google Scholar]
- WARREN L. The thiobarbituric acid assay of sialic acids. J Biol Chem. 1959 Aug;234(8):1971–1975. [PubMed] [Google Scholar]
