Pan-cancer mutational signature surveys correlated mutational signature with geospatial environmental exposures and viral infections

Background

Cancer has been disproportionally affecting minorities. Genomic-based cancer disparity analyses have been less common than conventional epidemiological studies. In the past decade, mutational signatures have been established as characteristic footprints of endogenous or exogenous carcinogens.

Methods

Integrating datasets of diverse cancer types from The Cancer Genome Atlas and geospatial environmental risks of the registry hospitals from the United States Environmental Protection Agency, we explored mutational signatures from the aspect of racial disparity concerning pollutant exposures. The raw geospatial environmental exposure data were refined to 449 air pollutants archived and modeled from 2007 to 2017 and aggregated to the census county level. Additionally, hepatitis B and C viruses and human papillomavirus infection statuses were incorporated into analyses for skin cancer, cervical cancer, and liver cancer.

Results

Mutation frequencies of key oncogenic genes varied substantially between different races. These differences were further translated into differences in mutational signatures. Survival analysis revealed that the increased pollution level is associated with worse survival. The analysis of the oncogenic virus revealed that aflatoxin, an affirmed carcinogen for liver cancer, was higher in Asian liver cancer patients than in White patients. The aflatoxin mutational signature was exacerbated by hepatitis infection for Asian patients but not for White patients, suggesting a predisposed genetic or genomic disadvantage for Asians concerning aflatoxin.

Conclusions

Environmental pollutant exposures increase a mutational signature level and worsen cancer prognosis, presenting a definite adverse risk factor for cancer patients.

[Study on the relationship between occupational stress and metabolic syndrome in operating room nursing staff of a third-class A hospital]

Objective: To explore the relationship between occupational stress and metabolic syndrome (MS) in operating room nurses. Methods: In July 2019, 179 nurses in the operating room of a third-class A hospital in Shandong Province were selected as the research objects. The self-designed questionnaire was used to investigate the general situation, and "Nurse Job Stressor Scale" was used to investigate the occupational stress level of nursing staff. The height, weight, waist circumference, blood pressure, fasting blood glucose, total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, ischemia-modified albumin, lipoprotein associated phospholipase A2 were measured. The nursing staff were divided into MS group and non-MS group, and the occupational stress levels of the two groups were compared. Chi square test or Fisher test were used to compare the counting data between groups; the measurement data were expressed by Mean±SD, and the comparison between groups was performed with t test. Multiple logistic regression analysis was used to analyze the influencing factors of MS. Results: The overall occupational stress level of nurses in operating room was (450.58±141.77) points, which was significantly lower than the norm score (P<0.05) ; Compared with non-MS group, the overall occupational stress level, work nature, workload and patient related factors in MS group were significantly higher, and the differences were statistically significant (P<0.05) ; The prevalence of abdominal obesity, hypertriglyceridemia, hyperglycemia and hypertension were significantly different among the groups with different occupational stress levels (P<0.05) . After adjusting waist circumference, triglyceride, systolic blood pressure, high density lipoprotein, ischemia modified albumin and lipoprotein associated phospholipase A2, the total score of occupational stress was the risk factor of MS in operating room nurses (P<0.05) . Conclusion: The occupational stress level of nurses in operating room is related to the prevalence of MS.

Myeloid leukemia with high EVI1 expression is sensitive to 5-aza-2'-deoxycytidine by targeting miR-9

PURPOSE

High expression of ecotropic viral integration site 1 (EVI1) has been associated with a poor prognosis in leukemia patients, but the underlying mechanism remains unclear. Aberrant expression of microRNAs plays critical roles in leukemia development. MiR-9 is a putative potential target of EVI1. We have investigated the regulating mechanism of miR-9 by EVI1 in leukemia cells.

METHODS

We first examined the relationship between miR-9 and EVI1 expression levels in nine leukemia cell lines by RT-PCR. Then we forced high expression of EVI1 in UoCM1 and K562 cells to confirm the downregulation of miR-9 by EVI1. Methylation of the miR-9 promoter region was detected by DNA bisulfite sequencing. We treated the EVI1-overexpressing cells with the hypomethylating agent 5-aza-2'-deoxycytidine (5-AZA) to reverse EVI1-induced hypermethylation of miR-9.

RESULTS

EVI1 and miR-9 expression was negative related. Forced expression of EVI1 downregulated miR-9 by inducing hypermethylation of the miR-9 promoter. 5-AZA reversed high EVI1-induced hypermethylation of the miR-9 promoter and restored the expression of miR-9. 5-AZA induced extensive apoptosis and inhibited proliferation through cell cycle arrest in EVI1-overexpressing leukemia cells.

CONCLUSIONS

Our results suggest that EVI1 may be involved in leukemia cell proliferation and apoptosis via the regulation of miR-9 promoter methylation. 5-AZA may represent a promising therapeutic option for EVI1-high leukemia patients.

Downregulation of CDC27 inhibits the proliferation of colorectal cancer cells via the accumulation of p21Cip1/Waf1

Dysregulated cell cycle progression has a critical role in tumorigenesis. Cell division cycle 27 (CDC27) is a core subunit of the anaphase-promoting complex/cyclosome, although the specific role of CDC27 in cancer remains unknown. In our study, we explored the biological and clinical significance of CDC27 in colorectal cancer (CRC) growth and progression and investigated the underlying molecular mechanisms. Results showed that CDC27 expression is significantly correlated with tumor progression and poor patient survival. Functional assays demonstrated that overexpression of CDC27 promoted proliferation in DLD1 cells, whereas knockdown of CDC27 in HCT116 cells inhibited proliferation both in vitro and in vivo. Further mechanistic investigation showed that CDC27 downregulation resulted in G1/S phase transition arrest via the significant accumulation of p21 in HCT116 cells, and the upregulation of CDC27 promoted G1/S phase transition via the attenuation of p21 in DLD1 cells. Furthermore, we also demonstrated that CDC27 regulated inhibitor of DNA binding 1 (ID1) protein expression in DLD1 and HCT116 cells, and rescue assays revealed that CDC27 regulated p21 expression through modulating ID1 expression. Taken together, our results indicate that CDC27 contributes to CRC cell proliferation via the modulation of ID1-mediated p21 regulation, which offers a novel approach to the inhibition of tumor growth. Indeed, these findings provide new perspectives for the future study of CDC27 as a target for CRC treatment.

[High frequency oscillatory ventilation with perfluorocarbon in rabbits with acute lung injury]

OBJECTIVE

To investigate the efficacy of high frequency oscillation with perfluorocarbon (PFC) in rabbits with acute lung injury (ALI).

METHODS

Twenty four rabbits with ALI induced by repeated saline lung lavage were randomly assigned to four groups: conventional mechanical ventilation (CMV) group, CMV + PFC group, high frequency oscillation (HFO) group and HFO + PFC group. All rabbits were ventilated for two hours. Blood gases, respiratory system dynamic compliance (Cdyn) and intrapulmonary shunt fraction (Qs/Qt) were measured and calculated at 30, 60, and 120 min during experiment.

RESULTS

Compared with the CMV, statistically improvements were shown in gas exchange, Cdyn and Qs/Qt at 30 min in the CMV + PFC group [PaO(2) 122 mm Hg +/- 15 mm Hg vs. 692 mm Hg +/- 82 mm Hg, PaCO(2) 29.1 mm Hg +/- 2.7 mm Hg vs. 47.1 mm Hg +/- 2.9 mm Hg, Cdyn (1.35 +/- 0.13) vs (0.97 +/- 0.13) ml.cm H(2)O(-1).kg(-1), Qs/Qt 18.1 +/- 1.1 vs.24.5 +/- 2.9] (P < 0.01 approximately 0.05) and remained stable for two hours. Compared with HFO, HFO + PFC improved oxygenation and ventilation more rapidly than HFO did. At 30 min intervals gas exchange and Qs/Qt were significantly improved (PaO(2) 174.9 +/- 18.5 vs 132.3 +/- 19.4, PaCO(2) 26.1 +/- 2.6 vs 34.9 +/- 4.6, Qs/Qt 17.1 +/- 2.4 vs 19.8 +/- 0.9) (P < 0.05)and remained stable to 60 min. The same differences were seen at 60 min.

CONCLUSION

In rabbits with ALI, CMV + PFC could induce a significant improvement in gas exchange and Cdyn. HFO + PFC leads more rapidmy to reach best gas exchange and Cdyn.

Experimental study of double-lumen, two-stage endotracheal tube during conventional mechanical ventilation in rabbits

OBJECTIVE

To evaluate the effects of a double-lumen, two-stage endotracheal tube on gas exchanges (ventilatory efficiency) during conventional mechanical ventilation, using a ventilator in rabbits.

DESIGN

Prospective, randomized, crossover laboratory animal trial.

SETTING

Research laboratory in the Beijing Children's Hospital.

SUBJECTS

Five adult New Zealand rabbits, weighing 3.2 to 3.7 kg.

INTERVENTIONS

A new type of endotracheal tube-the double-lumen two-stage endotracheal tube-was designed and tested for ventilation efficiency in rabbits with normal and injured lungs. The new tube (size 3.0 mm) was made out of two Portex endotracheal tubes (size 3.0 mm) by adhering two vertical cross-sections at the distal end of the two tubes. The new tube and a conventional endotracheal tube of the same size (inner diameter 3.0 mm) were randomly used in pressure control ventilation. Each trial was maintained for 30 mins.

MEASUREMENTS AND MAIN RESULTS

Effects from the two endotracheal tubes on pulmonary mechanics, hemodynamics, and gas exchange were observed. We measured peak inspiratory pressure, positive end-expiratory pressure (PEEP), intrinsic PEEP, mean airway pressure, and arterial blood and mixed expired gas variables (Pao2, Paco2, pH, and mixed expired gas Pco2). The new endotracheal tube acutely increased CO2 elimination in all animals with normal and injured lungs. Paco2 decreased from 46 +/- 4 to 36 +/- 5 torr (6.1 +/- 0.5 to 4.8 +/- 0.7 kPa; p < .01) in normal lungs and from 48 +/- 5 to 36 +/- 5 (6.4 +/- 0.7 to 4.8 +/- 0.7 kPa; p < .01). Meanwhile, tidal volume fraction decreased from 0.48 +/- 0.07 to 0.35 +/- 0.05 (p < .01) and from 0.56 +/- 0.07 to 0.40 +/- 0.07 (p < .01) in normal and injured lungs, respectively. Intrinsic PEEP of the new tube slightly increased, but there were no significant differences in comparison with the conventional tube.

CONCLUSION

Compared with the conventional endotracheal tube, the new double-lumen, two-stage endotracheal tube reduced Paco2 by decreasing anatomical deadspace in rabbits with normal and injured lungs under pressure control ventilation, thus enhancing ventilatory efficiency and reducing ventilator-induced injury.