[The efficacy and side effects of rigosertib combined with chemotherapy in KRAS mutant colorectal cancer mice]

Objective: To investigate the effect of rigosertib (RGS) combined with classic chemotherapy drugs including 5-fluorouracil, oxaliplatin, and irinotecan in colorectal cancer. Methods: Explore the synergy effects of RGS and 5-fluorouracil (5-FU), oxaliplatin (OXA), and irinotecan (IRI) on colorectal cancer by subcutaneously transplanted tumor models of mice. The mice were randomly divided into control group, RGS group, 5-FU group, OXA group, IRI group, 5-FU+ RGS group, OXA+ RGS group and IRI+ RGS group. The synergy effects of RGS and OXA on KRAS mutant colorectal cancer cell lines in vitro was detected by CCK-8. Ki-67 immunohistochemistry and TdT-mediated dUTP nick-end labeling (TUNEL) staining were performed on the mouse tumor tissue sections, and the extracted tumor tissue was analyzed by western blot. The blood samples of mice after chemotherapy and RGS treatment were collected, blood routine and liver and kidney function analysis were conducted, and H&E staining on liver sections was performed to observe the side effects of chemotherapy and RGS. Results: The subcutaneously transplanted tumor models were established successfully in all groups. 55 days after administration, the fold change of tumor size of OXA+ RGS group was 37.019±8.634, which is significantly smaller than 77.571±15.387 of RGS group (P=0.029) and 92.500±13.279 of OXA group (P=0.008). Immunohistochemical staining showed that the Ki-67 index of tumor tissue in control group, OXA group, RGS group and OXA+ RGS group were (100.0±16.8)%, (35.6±11.3)%, (54.5±18.1)% and (15.4±3.9)%, respectively. The Ki-67 index of OXA+ RGS group was significantly lower than that in control group (P=0.014), but there was no significant difference compared to OXA group and RGS group (OXA: P=0.549; RGS: P=0.218). TUNEL fluorescence staining showed that the apoptotic level of OXA+ RGS group was 3.878±0.547, which was significantly higher than 1.515±0.442 of OXA group (P=0.005) and 1.966±0.261 of RGS group (P=0.008). Western blot showed that the expressions of apoptosis related proteins such as cleaved-PARP, cleaved-caspase 3 and cleaved-caspase 8 in the tumor tissues of mice in the OXA+ RGS group were higher than those in control group, OXA group and RGS group. After the mice received RGS combined with chemotherapy drugs, there was no significant effect on liver and kidney function indexes, but the combined use of oxaliplatin and RGS significantly reduced the white blood cells [(0.385±0.215)×10(9)/L vs (5.598±0.605)×10(9)/L, P<0.001] and hemoglobin[(56.000±24.000)g/L vs (153.333±2.231)g/L, P=0.001] of the mice. RGS, chemotherapy combined with RGS and chemotherapy alone did not significantly increase the damage to liver cells. Conclusions: The combination of RGS and oxaliplatin has a stronger anti-tumor effect on KRAS mutant colorectal cancer. RGS single agent will not cause significant bone marrow suppression and hepatorenal injury in mice, but its side effects may increase correspondingly after combined with chemotherapy.

[Correlation of serum lipids levels of Alzheimer's disease patients with sex, age and apolipoprotein E gene polymorphism]

Objective: To explore the correlation of serum lipids levels of Alzheimer's disease (AD) patients with sex, age and apolipoprotein E (Apo E) gene polymorphism. Methods: The retrospective study method was used, and 407 AD patients (142 males and 265 females, aged 52-91 years) were selected from Beijing Tiantan Hospital from January 2015 to August 2021 as the research target, and 894 healthy persons (339 males and 555 females, aged 52-94 years) who did body examination were selected as the control group. The AD patients were divided into four age groups according to the age interval of 10 years, including 85 aged 50-59 years, 163 aged 60-69 years, 119 aged 70-79 years, and 40 aged more than 80 years. The serum lipids levels were detected by biochemical analyzer, including triglycerides (TG), cholesterol (CHO), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), apolipoproteinA1(Apo A1) and apolipoprotein B (Apo B). ApoE gene polymorphism were detected by PCR fluorescent probe method. Mann-Whitney U test and Kruskal-Wallis H test were used to compare the serum lipids levels in each group. Results: The levels of serum CHO and LDL-C were 3.30(1.41,4.82) mmol/L and 1.76(1.39,2.78) mmol/L in AD patients, and 4.84(4.24, 5.56) mmol/L and 2.91(2.36, 3.57) mmol/L in control group, and the levels of serum CHO and LDL-C of AD patients were significantly lower than control group (Z=-15.172,Z=-14.583, P<0.001, P<0.001). The levels of serum HDL-C and Apo B were 1.84(1.30, 3.88) mmol/L and 1.17(0.85, 1.57) g/L in AD patients, and 1.39(1.18, 1.64) mmol/L and 0.93(0.81, 1.09) g/L in control group, and the levels of serum HDL-C and Apo-B of AD patients were significantly higher than control group (Z=-12.249, Z=-9.706, P<0.001, P<0.001). There was no significant difference in TG and Apo A1 between 2 groups (Z=-1.577, Z=-0.408, P=0.115, P=0.683). The levels of TG, CHO, LDL-C in female AD patients were significantly higher than male patients (Z=-2.737, Z=-3.963, Z=-4.417, P=0.006, P<0.001, P<0.001). There were significant differences in TG, CHO, HDL-C, LDL-C, Apo A1 and Apo B among AD patients of all age groups (Z=11.263, Z=10.060, Z=40.246, Z=10.451, Z=24.315, Z=19.922, P=0.010, P=0.018, P<0.001, P=0.015, P<0.001, P<0.001). The serum CHO and LDL-C levels were positively correlated with age (r_s=0.160, r_s=0.174, P=0.001, P<0.001), and HDL-C, Apo A1 and Apo B levels were negatively correlated with age (r_s=-0.312, r_s=-0.272, r_s=-0.146, P<0.001, P<0.001, P=0.003), and there was no correlation between TG level and age in AD patients (r_s=0.086, P=0.082). There were 3 cases (3.33%) of E2, 43 cases of E3 (47.78%) and 44 cases of E4 (48.89%) in AD patients, and 22 cases (12.72%) of E2, 117 cases of E3 (67.63%) and 34 cases of E4 (19.65%) in control group. There was significant difference in Apo E genotype distribution between AD patients and control group (χ²=26.381, P<0.001). Apo E4 was the most common genotype in AD patients, and the proportion was 48.89%. Except for Apo A1(Z=7.821, P=0.020), there was no significant difference in TG, CHO, HDL-C, LDL-C and Apo B levels among all patients with different genotypes (Z=3.732, Z=1.677, Z=1.455, Z=1.619, Z=2.202, P=0.155, P=0.432, P=0.483, P=0.445, P=0.333). Conclusion: The levels of CHO and LDL-C decreased while the levels of HDL-C and Apo B increased in AD patients. The dyslipidemia in AD patients might be correlated with age, but not sex and Apo E genotypes.

Effects of vitamin E and selenium supplementation on esophageal adenocarcinogenesis in a surgical model with rats

Two well-known antioxidative nutrients, vitamin E and selenium, were used in this study to investigate possible inhibitory action against the formation of esophageal adenocarcinoma (EAC) in rats. In this model, carcinogenesis is believed to be driven by oxidative stress. Male Sprague-Dawley rats (8 weeks old) were divided into four groups and received esophagoduodenal anastomosis (EDA) surgery plus iron supplementation (12 mg/kg/week). Vitamin E and selenium were supplemented in the diet in the forms of alpha-tocopheryl acetate (750 IU/kg) and sodium selenate (1.7 mg Se/kg), which were 10 times the regular amounts in the basic AIN93M diet. At 40 weeks after surgery, all the EDA groups had lower body weights than the non-operated control group. Iron nutrition (hemoglobin, total serum iron and transferrin saturation) was normal as a result of iron supplementation after EDA. Vitamin E supplementation maintained the normal plasma level of alpha-tocopherol in EDA rats, but not those of gamma-tocopherol and retinol. Selenium supplementation increased the serum and liver selenium contents of the EDA rats. Histopathological analysis showed that selenium supplementation increased the incidence of EAC and the tumor volume. The selenium level in the tumor is higher than that in the duodenum of the same animal. Vitamin E supplementation, however, inhibited carcinogenesis, especially in the selenium-supplemented group. We believe that vitamin E exerts its effect through its antioxidative properties, and a high dose of inorganic selenium may promote carcinogenesis by enhancing oxidative stress.

Oxidative damage in an esophageal adenocarcinoma model with rats

Oxidative damage has long been related to carcinogenesis in human cancers and animal cancer models. Recently a rat esophageal adenocarcinoma (EAC) model was established in our laboratory by using esophagoduodenal anastomosis (EDA) plus iron supplementation. Our previous study suggested that iron supplementation enhanced inflammation and the production of reactive nitrogen species in the esophageal epithelium, which could contribute to esophageal adenocarcinogenesis. Here we further characterized oxidative damage in this model. We were particularly interested in how excess iron was deposited in the esophagus, and which cells were targeted by oxidative damage. Male Sprague-Dawley rats received iron supplementation (50 mg Fe/kg/month, i.p.) starting 4 weeks after EDA. The animals were killed at 11, 30 or 35 weeks after surgery. EAC appeared as early as week 11 after surgery, and increased over time, up to 60% at 35 weeks after surgery. All EACs were well-differentiated mucinous adenocarcinoma at the squamocolumnar junction. Iron deposition was found at the squamocolumnar junction and in the area with esophagitis. Esophageal iron overload could result from transient increase of blood iron after i.p. injection, and the overexpression of transferrin receptor in the premalignant columnar-lined esophagus (CLE) cells. Oxidative damage to DNA (8-hydroxy-2'-deoxyguanosine), protein (carbonyl content) and lipid (thiobarbituric acid reactive substance) in the esophagus was significantly higher than that of the non-operated control. CLE cells were believed to be the target cells of oxidative damage because they overexpressed heme oxygenase 1 and metallothionein, both known to be responsive to oxidative damage. We propose that oxidative damage plays an important role in the formation of EAC in the EDA model, and a similar situation may occur in humans with gastroesophageal reflux and iron over-nutrition.