Covalent coupling of methotrexate to dextran enhances the penetration of cytotoxicity into a tissue-like matrix

Wenbin Dang, O. Michael Colvin, Henry Brem, W. Mark Saltzman

Research output: Contribution to journalArticle

Abstract

For antitumor agents introduced directly into the intracranial space, the extent of penetration into tissue, and hence the effectiveness of therapy, depends on the rate of drug elimination from the tissue. To test the hypothesis that slowly eliminated agents would penetrate further through tissues, methotrexate (MTX)-dextran conjugates were produced by covalently linking MTX to dextran through a short-lived ester bond (MTX-ester-dextran; t( 1/2 ) ~3 days in buffered saline) and a longer-lived amide bond (MTX-amide- dextran; t(α) > 20 days in buffered saline). The ability of these agents to kill cells and to penetrate through tissue was evaluated using: (a) human brain tumor (H80) cells in a standard format; (b) H80 cells in a novel three- dimensional format that mimics many characteristics of intracranial tumors; and (c) 9L gliosarcoma in the rat brain. Penetration into three-dimensional tissue-like matrices was performed by suspending H80 cells in agarose gets within a hollow fiber that was permeable to MTX but not dextran and injecting MTX or MTX-dextran conjugates into one end of the fiber. The cytotoxicity of MTX-ester-dextran and MTX-amide-dextran against H80 was equivalent to unmodified MTX (50% inhibitory concentration, ~0.01 μg/ml). When released from a biodegradable polyanhydride polymer matrix, MTX and MTX-dextran conjugates retained their ability to inhibit dihydrofolate reductase activity. When MTX or MTX-dextran was diffused into the three-dimensional tumor cell matrix for 10 days, cytotoxic activity penetrated >2 cm for MTX- amide-dextran and ~1 cm for MTX or MTX-ester-dextran; this enhanced penetration correlated with the stability of the MTX-dextran linkage, intracranial polymeric delivery of MTX or MTX-amide-dextran to cats with intracranial 9L gliosarcoma produced modest but significant increases in survival; conjugation of MTX to dextran appeared to shift the dose-response curve to a lower dosage.

Original languageEnglish (US)
Pages (from-to)1729-1735
Number of pages7
JournalCancer Research
Volume54
Issue number7
StatePublished - Apr 1 1994

Fingerprint

Dextrans
Methotrexate
Amides
Esters
Gliosarcoma
Polyanhydrides
Tetrahydrofolate Dehydrogenase

ASJC Scopus subject areas

  • Cancer Research
  • Oncology

Cite this

Covalent coupling of methotrexate to dextran enhances the penetration of cytotoxicity into a tissue-like matrix. / Dang, Wenbin; Colvin, O. Michael; Brem, Henry; Saltzman, W. Mark.

In: Cancer Research, Vol. 54, No. 7, 01.04.1994, p. 1729-1735.

Research output: Contribution to journalArticle

Dang, Wenbin ; Colvin, O. Michael ; Brem, Henry ; Saltzman, W. Mark. / Covalent coupling of methotrexate to dextran enhances the penetration of cytotoxicity into a tissue-like matrix. In: Cancer Research. 1994 ; Vol. 54, No. 7. pp. 1729-1735.
@article{7b92eee2c5904835939d1e4bcb65b236,
title = "Covalent coupling of methotrexate to dextran enhances the penetration of cytotoxicity into a tissue-like matrix",
abstract = "For antitumor agents introduced directly into the intracranial space, the extent of penetration into tissue, and hence the effectiveness of therapy, depends on the rate of drug elimination from the tissue. To test the hypothesis that slowly eliminated agents would penetrate further through tissues, methotrexate (MTX)-dextran conjugates were produced by covalently linking MTX to dextran through a short-lived ester bond (MTX-ester-dextran; t( 1/2 ) ~3 days in buffered saline) and a longer-lived amide bond (MTX-amide- dextran; t(α) > 20 days in buffered saline). The ability of these agents to kill cells and to penetrate through tissue was evaluated using: (a) human brain tumor (H80) cells in a standard format; (b) H80 cells in a novel three- dimensional format that mimics many characteristics of intracranial tumors; and (c) 9L gliosarcoma in the rat brain. Penetration into three-dimensional tissue-like matrices was performed by suspending H80 cells in agarose gets within a hollow fiber that was permeable to MTX but not dextran and injecting MTX or MTX-dextran conjugates into one end of the fiber. The cytotoxicity of MTX-ester-dextran and MTX-amide-dextran against H80 was equivalent to unmodified MTX (50{\%} inhibitory concentration, ~0.01 μg/ml). When released from a biodegradable polyanhydride polymer matrix, MTX and MTX-dextran conjugates retained their ability to inhibit dihydrofolate reductase activity. When MTX or MTX-dextran was diffused into the three-dimensional tumor cell matrix for 10 days, cytotoxic activity penetrated >2 cm for MTX- amide-dextran and ~1 cm for MTX or MTX-ester-dextran; this enhanced penetration correlated with the stability of the MTX-dextran linkage, intracranial polymeric delivery of MTX or MTX-amide-dextran to cats with intracranial 9L gliosarcoma produced modest but significant increases in survival; conjugation of MTX to dextran appeared to shift the dose-response curve to a lower dosage.",
author = "Wenbin Dang and Colvin, {O. Michael} and Henry Brem and Saltzman, {W. Mark}",
year = "1994",
month = "4",
day = "1",
language = "English (US)",
volume = "54",
pages = "1729--1735",
journal = "Journal of Cancer Research",
issn = "0099-7013",
publisher = "American Association for Cancer Research Inc.",
number = "7",

}

TY - JOUR

T1 - Covalent coupling of methotrexate to dextran enhances the penetration of cytotoxicity into a tissue-like matrix

AU - Dang, Wenbin

AU - Colvin, O. Michael

AU - Brem, Henry

AU - Saltzman, W. Mark

PY - 1994/4/1

Y1 - 1994/4/1

N2 - For antitumor agents introduced directly into the intracranial space, the extent of penetration into tissue, and hence the effectiveness of therapy, depends on the rate of drug elimination from the tissue. To test the hypothesis that slowly eliminated agents would penetrate further through tissues, methotrexate (MTX)-dextran conjugates were produced by covalently linking MTX to dextran through a short-lived ester bond (MTX-ester-dextran; t( 1/2 ) ~3 days in buffered saline) and a longer-lived amide bond (MTX-amide- dextran; t(α) > 20 days in buffered saline). The ability of these agents to kill cells and to penetrate through tissue was evaluated using: (a) human brain tumor (H80) cells in a standard format; (b) H80 cells in a novel three- dimensional format that mimics many characteristics of intracranial tumors; and (c) 9L gliosarcoma in the rat brain. Penetration into three-dimensional tissue-like matrices was performed by suspending H80 cells in agarose gets within a hollow fiber that was permeable to MTX but not dextran and injecting MTX or MTX-dextran conjugates into one end of the fiber. The cytotoxicity of MTX-ester-dextran and MTX-amide-dextran against H80 was equivalent to unmodified MTX (50% inhibitory concentration, ~0.01 μg/ml). When released from a biodegradable polyanhydride polymer matrix, MTX and MTX-dextran conjugates retained their ability to inhibit dihydrofolate reductase activity. When MTX or MTX-dextran was diffused into the three-dimensional tumor cell matrix for 10 days, cytotoxic activity penetrated >2 cm for MTX- amide-dextran and ~1 cm for MTX or MTX-ester-dextran; this enhanced penetration correlated with the stability of the MTX-dextran linkage, intracranial polymeric delivery of MTX or MTX-amide-dextran to cats with intracranial 9L gliosarcoma produced modest but significant increases in survival; conjugation of MTX to dextran appeared to shift the dose-response curve to a lower dosage.

AB - For antitumor agents introduced directly into the intracranial space, the extent of penetration into tissue, and hence the effectiveness of therapy, depends on the rate of drug elimination from the tissue. To test the hypothesis that slowly eliminated agents would penetrate further through tissues, methotrexate (MTX)-dextran conjugates were produced by covalently linking MTX to dextran through a short-lived ester bond (MTX-ester-dextran; t( 1/2 ) ~3 days in buffered saline) and a longer-lived amide bond (MTX-amide- dextran; t(α) > 20 days in buffered saline). The ability of these agents to kill cells and to penetrate through tissue was evaluated using: (a) human brain tumor (H80) cells in a standard format; (b) H80 cells in a novel three- dimensional format that mimics many characteristics of intracranial tumors; and (c) 9L gliosarcoma in the rat brain. Penetration into three-dimensional tissue-like matrices was performed by suspending H80 cells in agarose gets within a hollow fiber that was permeable to MTX but not dextran and injecting MTX or MTX-dextran conjugates into one end of the fiber. The cytotoxicity of MTX-ester-dextran and MTX-amide-dextran against H80 was equivalent to unmodified MTX (50% inhibitory concentration, ~0.01 μg/ml). When released from a biodegradable polyanhydride polymer matrix, MTX and MTX-dextran conjugates retained their ability to inhibit dihydrofolate reductase activity. When MTX or MTX-dextran was diffused into the three-dimensional tumor cell matrix for 10 days, cytotoxic activity penetrated >2 cm for MTX- amide-dextran and ~1 cm for MTX or MTX-ester-dextran; this enhanced penetration correlated with the stability of the MTX-dextran linkage, intracranial polymeric delivery of MTX or MTX-amide-dextran to cats with intracranial 9L gliosarcoma produced modest but significant increases in survival; conjugation of MTX to dextran appeared to shift the dose-response curve to a lower dosage.

UR - http://www.scopus.com/inward/record.url?scp=0028281777&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0028281777&partnerID=8YFLogxK

M3 - Article

C2 - 7511049

AN - SCOPUS:0028281777

VL - 54

SP - 1729

EP - 1735

JO - Journal of Cancer Research

JF - Journal of Cancer Research

SN - 0099-7013

IS - 7

ER -