Elevated physiologic tumor pressure promotes proliferation and chemosensitivity in human osteosarcoma.
OBJECTIVE
This study investigates the effect of constitutively raised interstitial fluid pressure on osteosarcoma physiology and chemosensitivity.


METHODS
We did pressure and blood flow assessments at the time of open biopsy in patients with the diagnosis of high-grade osteosarcoma and correlated this to survival and chemotherapy-associated tumor necrosis. Osteosarcoma cell lines were then evaluated for proliferative and therapeutic indices in a replicated high-pressure environment.


RESULTS
Sixteen osteosarcomas in vivo were assessed and exhibited elevated interstitial fluid pressures (mean 35.2 +/- SD, 18.6 mmHg). This was not associated with significantly impeded blood flow as measured by a Doppler probe at a single site (P < 0.12). Nonetheless, greater chemotherapy-associated necrosis and associated longer survival were seen in tumors with higher interstitial fluid pressures (P < 0.05). In vitro, cells undergo significant physiologic changes under pressure. Osteosarcoma cell lines grown in a novel hydrostatically pressurized system had variable cell line-specific growth proportional to the level of pressure. They were more proliferative as indicated by cell cycle analysis with more cells in S phase after 48 hours of pressurization (P < 0.01). There was a significant elevation in the cell cycle-related transcription factors E2F-1 (P < 0.03) and E2F-4 (P < 0.002). These changes were associated with increased chemosensitivity. Cells tested under pressure showed an increased sensitivity to cisplatin (P < 0.00006) and doxorubicin (P < 0.03) reminiscent of the increased chemotherapy-associated necrosis seen in tumors with higher interstitial fluid pressure in the clinical study.


CONCLUSIONS
The results of this study suggest that cells in the in vivo pressurized environment are at a higher state of regenerative activity than is demonstrable in conventional cell culture systems. Variations in tumor interstitial fluid pressure have the potential to alter chemotherapeutic effects.
Nathan
Saminathan S
SS
Orthopaedic Surgery Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, 1275A York Avenue, New York, NY 10021, USA.
DiResta
Gene R
GR
Casas-Ganem
Jorge E
JE
Hoang
Bang H
BH
Sowers
Rebecca
R
Yang
Rui
R
Huvos
Andrew G
AG
Gorlick
Richard
R
Healey
John H
JH
D000293:Adolescent; D000328:Adult; D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology; D001274:Atmospheric Pressure; D001783:Blood Flow Velocity; D001859:Bone Neoplasms / Q000378:metabolism / Q000473:pathology; D049109:Cell Proliferation; D002648:Child; D002945:Cisplatin / Q000494:pharmacology; D004317:Doxorubicin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm; D045604:Extracellular Fluid / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D012516:Osteosarcoma / Q000378:metabolism* / Q000473:pathology*; D016196:S Phase / Q000187:drug effects / Q000502:physiology; D015996:Survival Rate; D014407:Tumor Cells, Cultured
D000903:Antibiotics, Antineoplastic; D000970:Antineoplastic Agents; D004317:Doxorubicin; D002945:Cisplatin