Serum levels of surfactant protein D are increased in mice with lung tumors.
Most murine lung tumors are composed of differentiated epithelial cells. We have reported previously that surfactant protein (SP)-D is expressed in urethane-induced tumors. Serum levels of SP-D are increased in patients with interstitial lung disease and acute respiratory distress syndrome and in rats with acute lung injury but have not been measured in mice. In this study, we sought to determine whether SP-D could be detected in murine serum and discovered that it was increased in mice bearing lung tumors. Serum SP-D concentration was 5.0 +/- 0.2 ng/ml in normal C57BL/6 mice, essentially absent in SP-D nulls, and 63.6 +/- 9.0 ng/ml in SP-D-overexpressing mice. SP-D in serum was verified by immunoblotting. Serum SP-D was increased in mice bearing tumors induced by three different protocols, and the SP-D level correlated with tumor volume. However, in mice with a single adenoma or a few adenomas, SP-D levels were usually within the normal range. SP-D was expressed by the tumor cells, and there was also a field effect whereby type II cells near the tumor expressed more SP-D than type II cells in the remainder of the lung. Serum SP-D was also increased by lung inflammation. In airway inflammation induced by aerosolized ovalbumin in sensitized BALB/c mice, the serum levels were elevated after challenge. In conclusion, serum SP-D concentration is increased in mice bearing lung tumors and generally reflects the tumor burden but is also elevated during lung inflammation.
Zhang
Feijie
F
National Jewish Medical and Research Center, Denver, Colorado 80206, USA.
Pao
William
W
Umphress
Sarah M
SM
Jakowlew
Sonia B
SB
Meyer
Amy M
AM
Dwyer-Nield
Lori D
LD
Nielsen
Larry D
LD
Takeda
Katsuyuki
K
Gelfand
Erwin W
EW
Fisher
James H
JH
Zhang
Lening
L
Malkinson
Alvin M
AM
Mason
Robert J
RJ
D000230:Adenocarcinoma / Q000097:blood* / Q000139:chemically induced / Q000235:genetics; D000818:Animals; D002273:Carcinogens; D017353:Gene Deletion; D015972:Gene Expression Regulation, Neoplastic; D011905:Genes, ras / Q000235:genetics; D008175:Lung Neoplasms / Q000097:blood* / Q000139:chemically induced / Q000235:genetics; D008297:Male; D051379:Mice; D008805:Mice, Inbred A; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008822:Mice, Transgenic; D010047:Ovalbumin / Q000276:immunology / Q000494:pharmacology; D037663:Pulmonary Surfactant-Associated Protein D / Q000097:blood* / Q000276:immunology; D051381:Rats; D016212:Transforming Growth Factor beta / Q000172:deficiency / Q000235:genetics; D014520:Urethane
D002273:Carcinogens; D037663:Pulmonary Surfactant-Associated Protein D; D016212:Transforming Growth Factor beta; D014520:Urethane; D010047:Ovalbumin