Effects Of Carbon Dioxide Pneumoperitoneum On The Activity Of ERK_1/2 And PI3K/Akt Signal Transduction Pathways Of Human Cervical Carcinoma Cell Line CaSki

Objective: To study the effects of CO₂ pneumoperitoneum on the core protein expressions of the ERK_1/2 and PI3K/Akt signal transduction pathways and the growth of human cervical carcinoma cell line CaSki in vitro by blocking above signal transduction pathways, for elucidating CO₂ pneumoperitoneum promoting mechanism on tumor growth and probing into a new method of weakening its promoting effect.Methods: 1.experimentation grouping: control group, CO₂ pneumoperitoneum group(CaSki cells were exposed to CO₂ pneumoperitoneum at 14mmHg for 2h), experimental group1–3(CaSki cells were exposed to CO₂ pneumoperitoneum at 14mmHg for 2h by being pre-disposed in 25,50 or 100μmol/l final concentrations of PD98059 which was a specific inhibitor of the ERK_1/2 signal transduction pathway), experimental groupⅠ–Ⅲ(CaSki cells were exposed to CO₂ pneumoperitoneum at 14mmHg for 2h by being pre-disposed in 20,40 or 60μmol/l final concentrations of LY294002 which was a specific inhibitor of the PI3K/Akt signal transduction pathway). 2. The expression of p-ERK protein in control group and CO₂ pneumoperitoneum group was detected by immunocytochemistry method. 3. The expression of p-ERK, ERK, p-Akt or Akt proteins was detected by Western blotting. 4. The effect of CO₂ pneumoperitoneum on the growth of human cervical carcinoma cell line CaSki was determined by spectrophotometer assay(MTT) and cell growth curves were made at the same time.Results:1. The results detected by immunocytochemistry showed that p-ERK protein mainly expressed at cytoplasm, slightly at the cell nucleus and its perimeter. The p-ERK protein was significantly expressed at not only cytoplasm but also cell nucleus after exposure to CO₂ pneumoperitoneum.2.The change of p-ERK and ERK protein expression: The expression of p-ERK and ERK was significantly higher in CO₂ pneumoperitoneum group than that in control group(P<0.05). The expression of p-ERK was significantly higher in experimental group 1, 2(The terminal concentrations of PD98059 correspondingly was 25 and 50μmol/l) compared to the control group(P<0.05). There was no significantly difference in the expression of p-ERK between experimental group 1 (The terminal concentrations of PD98059 was 100μmol/l) and the control group. The expression of ERK was significantly higher in experimental group 1–3 than that in control group (P<0.05). There was no significantly difference in the expression of ERK between CO₂ pneumoperitoneum group and each experimental group 1–3(P >0.05).3.The change of p-Akt and Akt protein expression: The expression of p-Akt and Akt was significantly higher in CO₂ pneumoperitoneum group than that in control group(P < 0.05). The expression of p-Akt was significantly higher in experimental groupâ… (The terminal concentration of LY294002 was 20μmol/l)in comparison with control group(P<0.05). There was no significantly difference in the expression of p-Akt between experimental groupâ…¡,â…¢(The terminal concentrations of LY294002 correspondingly was 40, 60μmol/l)and the control group(P >0.05). The expression of Akt was significantly higher in experimental groupⅠ–Ⅲin comparison with the control group(P<0.05). There was no significantly difference in the expression of Akt between CO₂ pneumoperitoneum group and each experimental groupⅠ–Ⅲ(P >0.05).4. The comparison of cell growth curves among groups: There was no significant difference of the absorbance values from the first day to the second day among groups(P >0.05). From the third day to the fifth day after exposure, the absorbance values in CO₂ pneumoperitoneum group were always significantly higher than those in the control group at different time ponint(P<0.05). Except for experimental group 1 and the control group, there was no significant difference of the absorbance values among all groups. Conclusions: The CO₂ pneumoperitoneum may contribute to increasing the growth of human cervical carcinoma cells in vitro and upregulating the activity of ERK_1/2 and PI3K/Akt signal transduction pathways. Upregulated activity of ERK_1/2 but not PI3K/Akt signal transduction pathways took part in promoting cell growth, which may be one reason for the promoting effect of CO₂ pneumoperitoneum on malignant growth. Specially blocking the ERK_1/2 signal transduction pathways may be a new method of weakening CO₂ pneumoperitoneum promoting effect on human cervical carcinoma cell.