Effects of carbon dioxide and nitrogen on adhesive growth and expressions of E-cadherin and VEGF of human colon cancer cell CCL-228

Low intraoperative end-tidal carbon dioxide levels are associated with improved recurrence-free survival after elective colorectal cancer surgery

STUDY OBJECTIVE

Higher levels of carbon dioxide (CO2) increase the invasive abilities of colon cancer cells in vitro. Studies assessing target values for end-tidal CO2 concentrations (EtCO2) to improve surgical outcome after colorectal cancer surgery are lacking. Therefore, we evaluated whether intraoperative EtCO2 was associated with differences in recurrence-free survival after elective colorectal cancer (CRC) surgery.

DESIGN

Single center, retrospective analysis.

SETTING

Anesthesia records, surgical databases and hospital information system of a tertiary university hospital.

PATIENTS

We analyzed 528 patients undergoing elective resection of colorectal cancer at Heidelberg University Hospital between 2009 and 2018.

INTERVENTIONS

None.

MEASUREMENTS

Intraoperative mean EtCO2 values were calculated. The study cohort was equally stratified into low-and high-EtCO2 groups. The primary endpoint measure was recurrence-free survival until last known follow-up. Groups were compared using Kaplan-Meier analysis. Cox-regression analysis was used to control for covariates. Sepsis, reoperations, surgical site infections and cardiovascular events during hospital stay, and overall survival were secondary outcomes.

MAIN RESULTS

Mean EtCO2 was 33.8 mmHg ±1.2 in the low- EtCO2 group vs. 37.3 mmHg ±1.6 in the high-EtCO2 group. Median follow-up was 3.8 (Q1-Q3, 2.5-5.1) years. Recurrence-free survival was higher in the low-EtCO2 group (log-rank-test: p = .024). After correction for confounding factors, lower EtCO2 was associated with increased recurrence-free survival (HR = 1.138, 95%-CI:1.015-1.276, p = .027); the hazard for the primary outcome decreased by 12.1% per 1 mmHg decrease in mean EtCO2. 1-year and 5-year survival was also higher in the low-EtCO2 group. We did not find differences in the other secondary endpoints.

CONCLUSIONS

Lower intraoperative EtCO2 target values in CRC surgery might benefit oncological outcome and should be evaluated in confirmative studies.

Effect of carbon dioxide pneumoperitoneum on human renal cell carcinoma proliferation and metastasis in an orthotropic xenograft nude mouse model

INTRODUCTION

This study aimed to explore the effect of carbon dioxide (CO2) pneumoperitoneum on tumor proliferation and metastasis in an orthotropic xenograft nude mice model of human renal cell carcinoma (RCC) and evaluate the safety of CO2 pneumoperitoneum laparoscopy for treating RCC.

MATERIAL AND METHODS

RCC 786-0 cells were injected to establish an orthotropic xenograft model. Fifty nude mice were given orthotropic inoculations and randomized to five groups: group A (control); group B (CO2 pneumoperitoneum for 2 h); group C (CO2 pneumoperitoneum for 4 h); group D (CO2 pneumoperitoneum for 4 h and 24 h after waking); group E (CO2 pneumoperitoneum for 4 h and 48 h after waking). The proliferation status was observed in RCC specimens by immunohistochemical staining for Ki67. The protein levels of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) were examined by western blotting.

RESULTS

All groups showed similar Ki67-positive staining in RCC samples (p > 0.05). The relative expression of HIF-1α and VEGF gradually increased in both group B and group C, as compared with group A, but only the difference between group C and group A reached statistical significance (p < 0.05). The protein levels of HIF-1α and VEGF decreased in both group D and group E, as compared with group B and group C; however, the differences between group D, group E, and group A did not reach statistical significance (p > 0.05).

CONCLUSIONS

In an orthotropic xenograft nude mice model of RCC, CO2 pneumoperitoneum has no effect on expression of the cellular proliferation marker Ki67. However, CO2 pneumoperitoneum rapidly induces transient expression of HIF-1α and VEGF. Thus, CO2 pneumoperitoneum laparoscopy may be a safe method for treating RCC.

Higher CO2-insufflation pressure inhibits the expression of adhesion molecules and the invasion potential of colon cancer cells

AIM: To investigate the influence of CO₂-insufflation pressure on adhesion, invasion and metastatic potential of colon cancer cells based on adhesion molecules expression.

METHODS: With an in vitro artificial pneumoperitoneum model, SW1116 human colon carcinoma cells were exposed to CO₂-insufflation in 5 different pressure groups: 6 mmHg, 9 mmHg, 12 mmHg, 15 mmHg and control group, respectively for 1 h. Expression of E-cadherin, ICAM-1, CD44 and E-selectin was measured at 0, 12, 24, 48 and 72 h after CO₂-insufflation using flow cytometry. The adhesion and invasion capacity of SW1116 cells before and after exposure to CO₂-insufflation was detected by cell adhesion/invasion assay in vitro. Each group of cells was injected intraperitoneally into 16 BALB/C mice. The number of visible abdominal cavity tumor nodules, visceral metastases and survival of the mice were recorded in each group.

RESULTS: The expression of E-cadherin, ICAM-1, CD44 and E-selectin in SW1116 cells were changed significantly following exposure to CO₂ insufflation at different pressures (P < 0.05). The expression of E-cadherin, CD44 and ICAM-1 decreased with increasing CO₂-insufflation pressure. The adhesive/invasive cells also decreased gradually with increasing pressure as determined by the adhesion/invasion assay. In animal experiments, the number of abdominal cavity tumor nodules in the 15 mmHg group was also significantly lower than that in the 6 mmHg group (29.7 ± 9.91 vs 41.7 ± 14.90, P = 0.046). However, the survival in each group was not statistically different.

CONCLUSION: CO₂-insufflation induced a temporary change in the adhesion and invasion capacity of cancer cells in vitro. Higher CO₂-insufflation pressure inhibited adhesion, invasion and metastatic potential in vitro and in vivo, which was associated with reduced expression of adhesion molecules.

Is carbon dioxide insufflation safe for laparoscopic surgery? A model to assess the effects of carbon dioxide on transitional-cell carcinoma growth, apoptosis, and necrosis

PURPOSE

To study the effects of carbon dioxide insufflation pressure and concentration on the adhesion, growth, apoptosis, and necrosis of transitional-cell carcinoma (TCC).

MATERIALS AND METHODS

Adhesion and growth of the AY-27 rat TCC cell line was measured after CO2 insufflation in vitro at different pressures ranging from 0 to 15 mm Hg and after incubation in CO2-air mixtures at 5%, 10%, and 15% CO2 by volume.

RESULTS

Tumor adhesion decreased significantly after CO2 insufflation. For all insufflation pressures, there was an increase in cell growth, apoptosis, and necrosis for the first 24 hours followed by a steady decline. High concentrations of CO2 (>5%) inhibited cell growth for only the first 48 hours. The effects of CO2 pneumoperitoneum on tumor-cell adhesion, growth inhibition, apoptosis, and necrosis were more prominent at high CO2 pressure (> or =15 mm Hg) and concentration (>5% CO2). However, insufflation pressure had a greater inhibitory effect on tumor growth than did CO2 concentration. High insufflation pressures and CO2 concentrations significantly decreased extracellular pH.

CONCLUSION

The short-term effect of CO2 on TCC growth and apoptosis is complex. Overall, CO2 has a toxic effect on TCC and inhibits cell adhesion and growth. High CO2 concentrations (>5%) and high insufflation pressures (> or =15 mm Hg) are most effective in decreasing tumor-cell adhesion and growth.

Effects of pneumoperitoneal gases and pressures on transitional cell carcinoma adhesion, growth, apoptosis and necrosis: an in vitro study

PURPOSE

We studied the effects of insufflation gas and pressure on the adhesion, growth, apoptosis and necrosis of transitional cell carcinoma (TCC) in an in vitro model.

MATERIALS AND METHODS

Tumor adhesion and cell growth of AY-27 rat TCC was measured after 3-hour incubation with CO2, N2 and He insufflation at different pressures (0, 10 and 15 mm Hg) in vitro. The effects of these gases on the rate of tumor cell apoptosis and necrosis were compared.

RESULTS

In vitro the tumor adhesion rate was lowest with CO2 and highest with N2. Higher gas pressures resulted in decreased adhesion rates for CO2 and He but increased adhesion rates for N2. N2 enhanced tumor cell proliferation at all pressures studied. He and CO2 resulted in an initial increase in cell proliferation in the first 24 hours, followed by a decrease in tumor growth. Extracellular medium turned acidic in CO2 (pH 6.27 to 6.39) but basic in N2 and He (pH 8.39 to 8.84). At all insufflation pressures studied apoptosis and necrosis rates were increased in the first 24 hours, followed by a decrease for CO2 and N2. He resulted in increasing apoptosis and necrosis throughout the study period.

CONCLUSIONS

The type of gas and insufflation pressure affects cell adhesion and tumor growth. There was a significant increase in tumor adhesion and proliferation with N2 insufflation compared with CO2 and He at 0 to 15 mm Hg pressures. CO2 demonstrated the greatest decrease in TCC adhesion and proliferation at 15 mm Hg pressure. Apoptosis and necrosis were highest for He compared with the other gases.

Effects of tumor suppressor gene NGX6 on growth of human colon cancer cell line HT-29

AIM: NGX6 is a novel tumor suppressor gene candidate, and the expression of NGX6 decreased in colon cancer specimen, which suggested that the down-regulation of NGX6 was closely related to tumorigenesis of colon cancer. This study was designed to explore effects of NGX6 on the cytobiological characteristics of human colon cancer cell line HT-29 and to elucidate the role of NGX6 in the colon cancer.

METHODS: The mammal expression vector of pcDNA3.1(+)/NGX6 was transfected into human colon cancer cell line HT-29 cells by liposome.The integration of the exogenous vector DNA and the expression of NGX6 were detected by dot blot and RT-PCR. Finally, the cytobiological characteristics of positive clone were analyzed by growth curves of cells, MTT, soft agar assay, FCM and xenograft.

RESULTS: pcDNA3.1(+)/NGX6/HT-29 cells grew slower than pcDNA3.1(+)/HT-29 and HT-29 cells (P < 0.05), and the PDT of pcDNA3.1(+)/NGX6/HT-29 cell was 34.5 hours, which was significantly longer than that of pcDNA3.1(+)/HT-29 cells (27.1 h) and HT-29 cells (23.0 h). FCM data showed that the overexpression of NGX6 blocked the progression of G1→S phase in cell cycle, and it also presented decreased clonogenicity in soft agar assay and tumor formation in nude mice.

CONCLUSION: The re-expression of NGX6 can reverse the malignant phenotype of human colon cancer cell line HT-29. Therefore, NGX6 gene may be a good candidate of tumor suppressor gene associated with colon cancer.