[Metformin suppresses hypoxia-inducible factor-1α expression in cancer-associated fibroblasts to block tumor-stromal cross-talk in breast cancer]

OBJECTIVE

To investigate the mechanism of metformin for regulating tumor-stromal cell cross-talk in breast cancer.

METHODS

Tumor associated fibroblasts (CAFs) co-cultured with breast cancer cells were treated with metformin, and the changes in expressions of hypoxia-inducible factor-1α (HIF-1α), p-AMPK, stroma-derived factor-1 (SDF-1) and interleukin-8 (IL-8) in the CAFs were detected using ELISA, RT-qPCR or Western blotting; Transwell assay was used to evaluate the invasiveness of the tumor cells and its changes following treatment with exogenous SDF-1, IL-8 and TGF-β1. The effects of HIF-1α shRNA or overexpression plasmid, AMPK shRNA, and treatment with OG (a proline hydroxylase inhibitor) or 2-OXO (a proline hydroxylase activator) were examined on p-AMPK, HIF-1α, SDF-1 and IL-8 expressions and invasiveness of the CAFs.

RESULTS

Metformin treatment significantly increased the expression levels of p-AMPK, SDF-1 and IL-8 (P<0.05) and decreased HIF-1α expression (P<0.05) without affecting AMPK expression level (P>0.05) in the CAFs. The invasion ability of metformintreated breast cancer cells was significantly decreased (P<0.05). Exogenous SDF-1 and IL-8, HIF-1α overexpression, and OGinduced upregulation of HIF-1α all significantly attenuated the inhibitory effects of metformin on breast cancer cell invasion (P<0.05) and HIF-1α, SDF-1 and IL-8 expressions in CAFs (P<0.05). Transfection with HIF-1α shRNA or treatment with 2-OXO significantly decreased the invasiveness of breast cancer cells (P<0.05). P-AMPK knockdown significantly suppressed the inhibitory effect of metformin on HIF-1α expression in CAFs and on invasion of breast cancer cells (P<0.05). Treatment with TGF-β1 partially decreased the inhibitory effect of metformin on HIF-1α expression in CAFs and invasiveness of the breast cancer cells (P<0.05).

CONCLUSION

Metformin suppresses HIF-1α expression in CAFs to block tumor-stromal cross talk in breast cancer.

[Construction and validation of an in-hospital mortality risk prediction model for patients receiving VA-ECMO: a retrospective multi-center case-control study]

OBJECTIVE

To investigate the risk factors of in-hospital mortality and establish a risk prediction model for patients receiving venoarterial extracorporeal membrane oxygenation (VA-ECMO).

METHODS

We retrospectively collected the data of 302 patients receiving VA-ECMO in ICU of 3 hospitals in Guangdong Province between January, 2015 and January, 2022 using a convenience sampling method. The patients were divided into a derivation cohort (201 cases) and a validation cohort (101 cases). Univariate and multivariate logistic regression analyses were used to analyze the risk factors for in-hospital death of these patients, based on which a risk prediction model was established in the form of a nomogram. The receiver operator characteristic (ROC) curve, calibration curve and clinical decision curve were used to evaluate the discrimination ability, calibration and clinical validity of this model.

RESULTS

The in-hospital mortality risk prediction model was established based the risk factors including hypertension (OR=3.694, 95% CI: 1.582-8.621), continuous renal replacement therapy (OR=9.661, 95%CI: 4.103-22.745), elevated Na2 + level (OR=1.048, 95% CI: 1.003-1.095) and increased hemoglobin level (OR=0.987, 95% CI: 0.977-0.998). In the derivation cohort, the area under the ROC curve (AUC) of this model was 0.829 (95% CI: 0.770-0.889), greater than those of the 4 single factors (all AUC < 0.800), APACHE II Score (AUC=0.777, 95% CI: 0.714-0.840) and the SOFA Score (AUC=0.721, 95% CI: 0.647-0.796). The results of internal validation showed that the AUC of the model was 0.774 (95% CI: 0.679-0.869), and the goodness of fit test showed a good fitting of this model (χ2=4.629, P>0.05).

CONCLUSION

The risk prediction model for in-hospital mortality of patients on VA-ECMO has good differentiation, calibration and clinical effectiveness and outperforms the commonly used disease severity scoring system, and thus can be used for assessing disease severity and prognostic risk level in critically ill patients.

[Sivelestat sodium for treatment of patients with COVID-19-associated acute respiratory distress syndrome in intensive care unit: a single-center retrospective cohort study]

OBJECTIVE

To investigate the effect of sivelestat sodium on survival, oxygenation index, and serum markers for infection in critically ill patients with COVID-19-associated acute respiratory distress syndrome (ARDS).

METHODS

This retrospectively study was performed among the critically ill patients with COVID-19-associated ARDS admitted in the intensive care unit (ICU) at Nanfang Hospital, Southern Medical University. We collected the clinical data of the patients on the first day of ICU admission and on the day of discharge and laboratory tests results of interleukin-6 (IL-6), C-reactive protein (CRP) and procalcitonin (PCT) and oxygenation index on days 1, 3 and 7 following ICU admission. Propensity-score matching was used to match the patients receiving sivelestat sodium to those without the treatment. Cox proportional hazards model and linear regression analysis were used to assess the association of sivelestat sodium treatment with in-hospital mortality and the length of hospital stay.

RESULTS

A total of 199 patients with COVID-19-associated ARDS patients were included for data analysis. After propensity-score matching PSM, 35 patients receiving sivelestat sodium were matched to 70 patients without the treatment. Treatment with of sivelestat sodium was not associated with the reduction of in- hospital mortality (P=0.36), prolonged ICU stay (P=0.39), hospital stay (P=0.68) or improved oxygenation index (P>0.05) of the patients. No significant difference was found in serum CRP or PCT levels between the patients with and without sivelestat sodium treatment, but a significant reduction in IL-6 level was found in sivelestat sodium group (P=0.016).

CONCLUSION

Sivelestat sodium treatment is not correlated with the reduction of mortality or length of hospital stay, but is associated with reduced serum IL-6 level in patients with COVID-19-associated ARDS.