Resistance of tumor interstitial pressure to the penetration of intraperitoneally delivered antibodies into metastatic ovarian tumors.
OBJECTIVE
Despite evidence that regional chemotherapy improves the treatment of metastatic peritoneal ovarian carcinoma, monoclonal antibodies have not shown significant success in i.p. delivery. The present study was designed to address the hypothesis that convective penetration of macromolecular antineoplastic agents depends on a positive pressure difference between the i.p. therapeutic solution and the tumor.


METHODS
Nude rats with human ovarian xenografts implanted in the abdominal wall were used in experiments to facilitate in vivo measurement of tumor pressure and the treatment of the tumor with i.p. solutions at high pressures. Penetration of (125)I-labeled trastuzumab was measured with quantitative autoradiography.


RESULTS
Tumor pressure profiles showed peak pressures of 32 mm Hg with mean pressures (+/- SD, mm Hg) in 12 SKOV3 tumors of 9.7 +/- 8.3 and in 15 OVCAR3 tumors of 12.5 +/- 7.0. I.p. therapeutic dwells at 6 to 8 mm Hg (maximum feasible pressure) showed significantly less penetration of trastuzumab than in adjacent normal muscle. To establish a driving force for convection into the tumor, various maneuvers were attempted to reduce tumor pressure, including treatment with taxanes or prostaglandin E(1), elimination of tumor circulation, and removal of the tumor capsule. Tumor decapsulation decreased the pressure to zero but did not enhance the penetration of antibody. Binding to specific trastuzumab receptors on each tumor was shown to be not a significant barrier to antibody penetration.


CONCLUSIONS
The results only partially support our hypothesis and imply that the microenvironment of the tumor is in itself a major barrier to delivery of charged macromolecules.
Flessner
Michael F
MF
Department of Medicine, University of Mississippi Medical Center, Jackson, Mississippi 39216, USA. Mflessner@medicine.umsmed.edu
Choi
Jaewah
J
Credit
Kimberly
K
Deverkadra
Ravi
R
Henderson
Karla
K
D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D001775:Blood Circulation / Q000187:drug effects; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D007274:Injections, Intraperitoneal; D007457:Iodine Radioisotopes; D009362:Neoplasm Metastasis; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D010537:Peritoneum / Q000378:metabolism; D011312:Pressure; D051381:Rats; D011923:Rats, Nude; D000068878:Trastuzumab; D023041:Xenograft Model Antitumor Assays / Q000379:methods
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D007457:Iodine Radioisotopes; D000068878:Trastuzumab