Artesunate alleviates 5-fluorouracil-induced intestinal damage by suppressing cellular senescence and enhances its antitumor activity

BACKGROUND

Colorectal cancer (CRC) is one of the most prevalent diagnosed malignancies and one of the leading causes of cancer-related deaths worldwide. 5-Fluorouracil (5-FU) and its combination regimen are commonly used as primary chemotherapeutic agents for advanced CRC. Intestinal mucositis is one of the most frequent side effects of 5-FU. Artesunate (Arte) is derived from the wormwood plant Artemisia annua. Arte is not only effective against malaria but also diabetes, atherosclerosis, inflammation, and other conditions. The mechanism by which 5-FU damages the intestinal tract is unclear, and there is no standard treatment for diarrhea caused by 5-FU. Therefore, it is critical to discover novel and promising therapeutic drugs for 5-FU side effect treatment.

METHODS

The morphology and expression of genes and proteins associated with the aging of HUVECs, HIECs, and intestinal tissues were compared to the those of the control group. The cell lines and tissues were evaluated by SA-β-Gal staining, Western blotting, and RT‒qPCR. HIEC and HCT116 cell viability was assessed in vitro by a CCK-8 assay and in vivo by a subcutaneous tumor mouse assay. Tumor cell proliferation and apoptosis was evaluated by immunohistochemistry.

RESULTS

Here, we report that Arte alleviates the adverse side effects caused by 5-FU in intestinal tissue, and that 5-FU-induced intestinal damage is associated with drug-induced chemical inflammation and an increase in the proportion of senescent cells. Arte decreases the ratio of SA-β-Gal-positive cells and downregulated the expression of aging-related proteins (p53, p16) and aging-related genes (p53, p21). Mechanistically, Arte relieves intestinal injury by inhibiting mTOR expression, which is associated with the regulation of aging. Moreover, Arte suppresses the p38MAPK and NF-κB signaling pathways, which are related to inflammation regulation. In addition, the combined therapy of Arte plus 5-FU significantly decreases cancer cell viability in vitro. Arte and 5-FU synergistically reduce the growth of colorectal cancer (CRC) xenografts in vivo.

CONCLUSIONS

Overall, our findings point to the crucial treatment effect of Arte on inflammation, intestinal cell senescence, and CRC cell proliferation and offer a new option for CRC treatment.

Anti-inflammation and anti-aging mechanisms of mercaptopurine in vivo and in vitro

Skin is the biggest organ of the human body, which easily gets irritated by exposure to the sun. Skin photoaging and acute photodamage are caused by intense UV-B radiation. Therefore, it is imperative to find new compounds to prevent skin damage and aging. Mercaptopurine is an immunologic agent commonly used for treating Acute lymphoblastic leukemia and inflammatory bowel disease. The beneficial effects of mercaptopurine on the skin have not been reported, and its intrinsic mechanism of action is unclear. Therefore, this study was to explore mercaptopurine when exposed to UV-B radiation in HacaT cells and C57BL6 mice aging and damage effects. The model of in vivo UV-B-induced skin damage and skin photoaging was established, and the impact of mercaptopurine on cell and animal skin was studied. The study found that mercaptopurine, on the one hand, inhibits cellular and animal senescence. On the other, it inhibits the expression of mitogen-activated protein kinase (MAPK) and the nuclear factor κB (NF-κB), which are important signaling molecules in the early UV-B reaction signaling pathway. In addition, mercaptopurine downregulates matrix metalloproteinase expression, increases collagen fiber content, and facilitates collagen synthesis. Treatment with mercaptopurine also inhibits the expression of inflammatory factors and reduces inflammatory cell infiltration of the skin. In conclusion, our study elucidates mercaptopurine's anti-photoaging and anti-inflammatory activity in cellular and animal models.

Belinostat (PXD101) resists UVB irradiation-induced cellular senescence and skin photoaging

Belinostat (PXD101), a new histone deacetylase inhibitor, has shown good performance in various cancer treatments and has been approved by the FDA for the treatment of recurrent or refractory peripheral T-cell lymphoma (PTCL) in patients with drugs. PXD101 is considered to have certain anti-allergic and anti-inflammatory properties, but its beneficial effects in UVB-induced skin photoaging have not been reported. In a recent study, HacaT cells and C57BL6 mice were used to study the impact of PXD101 on UVB-induced cellular senescence and skin photoaging and to explore their potential mechanisms of action. Studies have shown that PXD101 inhibits UVB-induced HacaT cell senescence, which appears to be achieved by inhibiting activation of the UVB-induced NF-κB/p65 signaling pathway. At the same time, PXD101 inhibits the expression of MMPs. In addition, PXD101 alleviated skin damage on the dorsal skin of mice, reduced skin aging and inflammation, increased collagen fiber synthesis, and restored UVB-induced epidermal thickening. In short, we believe that PXD101 effectively inhibits cellular senescence and skin photoaging caused by UVB exposure, a potential method for developing clinical prevention and treatment of skin aging.

[A Luciferase-EGFP Reporter System for the Evaluation of DNA Methylation in Mammalian Cells]

DNA methylation is an essential epigenetic modification involved in numerous biological processes. Here, we present a cell-based system pLTR-Luc2P-EGFP for evaluation of DNA methylation in mammalian cells. In this system, the expression of reporter gene luciferase2P (Luc2P)-EGFP is under the control of HIV-1 promoter 5' long terminal repeat (LTR), which contains multiple CpG sites. Once these sites are methylated, the expression of Luc2P-EGFP is turned off, which may be visualized under fluorescence microscopy, with quantification performed in luciferase activity assay. As a proof of principle, pLTR-Luc2P-EGFP was methylated in vitro, and transfected into 293T cells, where the reduction of Luc2P-EGFP expression was confirmed. Premixed reporter DNA samples with the methylation levels varying from 0 to 100% were used for quantitative measurements of DNA methylation. The resulting standard curves indicated the accuracy of luciferase activity exceeding that of the Western blotting against EGFP. The Bland-Altman analysis showed that data from luciferase activity assay were in good agreement with the actual DNA methylation levels. In summary, we have established a reporter system coupled with reliable detection technique capable of efficient quantifying the changes in methylation in mammalian cells. This system may be utilized as a high throughput screening tool for identifying molecules that modulate DNA methylation.

A Luciferase-EGFP Reporter System for the Evaluation of DNA Methylation in Mammalian Cells

DNA methylation is an essential epigenetic modification involved in numerous biological processes. Here, we present a cell-based system pLTR-Luc2P-EGFP for evaluation of DNA methylation in mammalian cells. In this system, the expression of reporter gene luciferase2P (Luc2P)-EGFP is under the control of HIV-1 promoter 5' long terminal repeat (LTR), which contains multiple CpG sites. Once these sites are methylated, the expression of Luc2P-EGFP is turned off, which may be visualized under fluorescence microscopy, with quantification performed in luciferase activity assay. As a proof of principle, pLTR-Luc2P-EGFP was methylated in vitro, and transfected into 293T cells, where the reduction of Luc2P-EGFP expression was confirmed. Premixed reporter DNA samples with the methylation levels varying from 0 to 100% were used for quantitative measurements of DNA methylation. The resulting standard curves indicated the accuracy of luciferase activity exceeding that of the Western blotting against EGFP. The Bland–Altman analysis showed that data from luciferase activity assay were in good agreement with the actual DNA methylation levels. In summary, we have established a reporter system coupled with reliable detection technique capable of efficient quantifying the changes in methylation in mammalian cells. This system may be utilized as a high throughput screening tool for identifying molecules that modulate DNA methylation.

[Epidemiological investigation of a family clustering of COVID-19]

Objective: To investigate the epidemiological characteristics of a family clustering of COVID-19. Methods: Field epidemiological survey was conducted. Results: Case 1 of the long-term residents from Hubei province was the source of infection of this family clustering. There were 6 cases (from case 2 to case 7) infected in the whole incubation period. The incubation period was more than 14 days for 3 of the second-generation cases. Routes of transmission included respiratory droplets (from case 1 transmitted to case 6, from case 1 to her family members) and close contact (from case 1 to other cases in her family). All the age groups were generally susceptible, while elderly were easier to progress to critically ill. Besides respiratory symptoms, there were also gastrointestinal symptoms, of which diarrhea was the most common one. Conclusions: Family clustering had been an important part for COVID-19 cases.

Prostate-specific antigen screening for prostate cancer: benefits for patients with highly aggressive prostate cancer

The PSA screening for 25 years in America is the biggest cohort study in a field of public health.27 We should realize not only the significance of the early diagnosis and treatment of PCa, but also the dramatic decrease in PCaMR from 2002 to 2008. The data from the IARC were especially noteworthy.Moreover, the patients with highly aggressive PCa, who account for more than 30% of all PCa patients, could only be diagnosed earlier by PSA screening. The patients would thus gain the opportunity for earlier treatment and would have a prolonged, higher quality life-span. However, the complications of interventional treatments, including biopsy,radical prostatectomy and/or radiation therapy,will become more avoidable in the near future.According to the supporting evidence for the decrease in PCa mortality in PSA screening, we strongly hope that the USPSTF changes the 'D' recommendation for PSA screening.