Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 6 July 2007:
Vol. 317. no. 5834, pp. 121 - 124
DOI: 10.1126/science.1140485
Prev | Table of Contents | Next

Reports

Gender Disparity in Liver Cancer Due to Sex Differences in MyD88-Dependent IL-6 Production

Willscott E. Naugler1,2, Toshiharu Sakurai1, Sunhwa Kim1, Shin Maeda3, KyoungHyun Kim1, Ahmed M. Elsharkawy1,4 and Michael Karin1*

1 Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology and Cancer Center, University of California, San Diego, CA 93093, USA.
2 Department of Medicine, Division of Gastroenterology, University of California, San Diego, CA 93093, USA.
3 Division of Gastroenterology, The Institute for Adult Diseases, Asahi Life Foundation, 1-6-1 Marunouchi, Chiyoda-ku, Tokyo 100-0005, Japan.
4 Liver Research Group, University of Newcastle, Newcastle Upon Tyne NE2 4HH, UK.


Figure 1 Fig. 1. Differential IL-6 production after chemically induced liver injury. (A) Concentration of IL-6 in serum of male and female WT mice after injection of DEN (100 mg per kg of body weight; n =3 mice per time point). (B) IL-6 mRNA levels in livers of male, female, or ovariectomized (OVX; ovariectomy was done 2 weeks before DEN administration) female mice 4 hours after DEN injection. E2 (50 µg/kg)incornoilwas injected intraperitoneally 2 hours before DEN was administered. (C) Male B6 mice (n =3) were injected with ER{alpha}-specific agonist propyl-pyrazole-trisphenol (PPT; 5 µg/kg in corn oil) 2 hours before DEN injection, and serum IL-6 was measured at the indicated times after DEN injection. Results in (A) to (C) are means ± SE. Asterisks indicate a significant (P < 0.05; Student's t test) difference relative to WT male mice. [View Larger Version of this Image (13K GIF file)]
 

Figure 2 Fig. 2. Lower incidence of HCC tumors and longer survival of IL-6–/– mice. (A)Livers of 8-month-old DEN-treated mice. Multiple HCCs are seen only in WT male liver. (B) Incidence of HCC (> 0.5 mm) in WT male (n = 14), WT female (n = 13), IL-6–/– male (n = 14), and IL-6–/– female (n = 15) mice 8 months after DEN (25 mg/kg) injection. Asterisks indicate significant (P < 0.05; Student's t test) differences relative to WT male mice. (C) Survival curves of WT and IL-6–/– mice injected with DEN (25 mg/kg) at 15 days of age (P = 0.0006; log-rank test for significance). [View Larger Version of this Image (41K GIF file)]
 

Figure 3 Fig. 3. Influence of gender and IL-6 on hepatic injury and compensatory proliferation. (A)Male WT or IL-6–/– mice (n = 3) were given DEN (100 mg/kg), and ALT (alanine aminotransferase) in serum was measured. (B) Livers of male WT or IL-6–/– mice (n = 3) were assessed for apoptosis by TUNEL (terminal deoxynucleotidyl transferase– mediated dUTP nick-end labeling) staining after DEN injection. (C) Hepatocyte proliferation in livers of DEN-injected male WT or IL-6–/– mice (n = 3) was assessed by injecting mice with bromodeoxyrudine (BrdU) (1 mg per mouse) 2 hours before the liver was removed. BrdU-positive cells were identified by immunostaining. (D) Serum ALT was measured 48 hours after DEN injection (n = 3 per group). OVX: female mice ovariectomized 2 weeks before DEN administration. E2 (50 µg/kg) in corn oil was injected 2 hours before DEN. Similar studies assessing differences between male and female mice (n = 3) were done for apoptosis (E) and proliferation (F). (G) Six-week-old male B6 mice (n = 3) were given E2 or vehicle (corn oil) 2 hours before DEN injection. Recombinant IL-6 (10 µg) or sham buffer (phosphate-buffered saline) was given subcutaneously at the time of DEN administration. Serum ALT was measured 48 hours later. (H) Male ER{alpha}–/– and ERß–/– mice and littermate heterozygote controls (n = 3) were injected with E2 (50 µg) in corn oil or vehicle 2 hours before DEN injection, and serum ALT was measured 50 hours later. (I)Malemice(n = 3 per point) were injected with PPT (5 mg/kg in corn oil) or vehicle 2 hours before DEN injection, and serum ALT was measured 50 hours later. All results for (A) to (I) are means ± SE, and asterisks indicate P < 0.05 (Student's t test). (J) Cells from livers of male, female, and IL-6–/– mice were lysed at the indicated times after DEN injection. STAT3 and JNK activation, and I{kappa}B{alpha} degradation, were assessed by separating with SDS–polyacrylamide gel electrophoresis and immunoblotting with antibodies to the indicated proteins. Phosphorylation (P) of STAT3 and JNK indicates activation. Phospho-STAT3 and STAT3 were from one gel, as were Phospho-JNK and JNK1/2, and I{kappa}B{alpha} and actin. [View Larger Version of this Image (25K GIF file)]
 

Figure 4 Fig. 4. Requirement of MyD88 for IL-6 production, injury, and hepatocarcinogenesis after DEN treatment. (A)Accumulation of IL-6 mRNA was measured by real-time polymerase chain reaction in KCs from male WT, IKKß–/–, or MyD88–/– mice (n =3 experiments per time point) after incubation with LPS (10 ng/ml) or necrotic debris prepared by cycles of freezethawing of primary hepatocytes. Where indicated, cells were incubated with E2 (10 ng/ml) 30 min before stimulation. (B and C) Male WT and MyD88–/– mice were injected with DEN, and liver IL-6 mRNA (B) or serum ALT (C) was measured. (D and E) Number of HCCs(D) and sizes (E) in livers of WT and MyD88–/– male mice 8 months after DEN (25 mg/kg) administration. Results in (A) to (E) are means ± SE. Asterisks indicate a significant (P <0.05; Student's t test) difference relative to WT males. [View Larger Version of this Image (13K GIF file)]
 

To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)