Melanoma-associated antigen A1 (MAGEA1) and BORIS (also known as CTCFL) are members of the cancer testis antigen (CTA) family. Their functions and expression-regulation mechanisms are not fully understood. In this study, we reveal new functions and regulatory mechanisms of MAGEA1 and BORIS in breast cancer cells, which we investigated in parental and genetically manipulated breast cancer cells via gene overexpression or siRNA-mediated downregulation. We identified the interaction between MAGEA1 and CTCF, which is required for the binding of MAGEA1 to the BORIS promoter and is critical for the recruitment of DNMT3a. A protein complex containing MAGEA1, CTCF and DNMT3a was formed before or after conjunction with the BORIS promoter. The binding of this complex to the BORIS promoter accounts for the hypermethylation and repression of BORIS expression, which results in cell death in the breast cancer cell lines tested. Multiple approaches were employed, including co-immunoprecipitation, glutathione S-transferase pull-down assay, co-localization and cell death analyses using annexin V-FITC/propidium iodide double-staining and caspase 3 activation assays, chromatin immunoprecipitation and bisulfite sequencing PCR assays for methylation. Our results have implications for the development of strategies in CTA-based immune therapeutics.
Most older patients with esophageal cancer cannot complete the standard concurrent chemoradiotherapy (CCRT). An effective and tolerable chemoradiotherapy regimen for older patients is needed.
Objective
To evaluate the efficacy and toxic effects of CCRT with S-1 vs radiotherapy (RT) alone in older patients with esophageal cancer.
Design, Setting, and Participants
A randomized, open-label, phase 3 clinical trial was conducted at 23 Chinese centers between June 1, 2016, and August 31, 2018. The study enrolled 298 patients aged 70 to 85 years. Eligible participants had histologically confirmed esophageal cancer, stage IB to IVB disease based on the 6th edition of the American Joint Committee on Cancer (stage IVB: only metastasis to the supraclavicular/celiac lymph nodes) and an Eastern Cooperative Oncology Group performance status of 0 to 1. Data analysis was performed from August 1, 2020, to March 10, 2021.
Interventions
Patients were stratified according to age (<80 vs ≥80 years) and tumor length (<5 vs ≥5 cm) and randomly assigned (1:1) to receive either CCRT with S-1 or RT alone.
Main Outcomes and Measures
The primary end point was the 2-year overall survival rate using intention-to-treat analysis.
Results
Of the 298 patients enrolled, 180 (60.4%) were men. The median age was 77 (interquartile range, 74-79) years in the CCRT group and 77 (interquartile range, 74-80) years in the RT alone group. A total of 151 patients (50.7%) had stage III or IV disease. The CCRT group had a significantly higher complete response rate than the RT group (41.6% vs 26.8%;P = .007). Surviving patients had a median follow-up of 33.9 months (interquartile range: 28.5-38.2 months), and the CCRT group had a significantly higher 2-year overall survival rate (53.2% vs 35.8%; hazard ratio, 0.63; 95% CI, 0.47-0.85;P = .002). There were no significant differences in the incidence of grade 3 or higher toxic effects between the CCRT and RT groups except that grade 3 or higher leukopenia occurred in more patients in the CCRT group (9.5% vs 2.7%;P = .01). Treatment-related deaths were observed in 3 patients (2.0%) in the CCRT group and 4 patients (2.7%) in the RT group.
Conclusions and Relevance
In this phase 3 randomized clinical trial, CCRT with S-1 was tolerable and provided significant benefits over RT alone in older patients with esophageal cancer.
Inverse electron demand Diels–Alder reactions have gained comprehensive attraction in recent years. Accordingly, the synthetic approaches for one of the coupling partners, namely s-tetrazine, have been extensively investigated. Generally, the main synthetic method of s-tetrazine relied on the condensation of two nitriles to give the corresponding symmetric/asymmetric tetrazines with moderate to excellent yields. However, the practical synthesis route and commercial/synthetic availability of the feedstock nitriles are still elusive. It is therefore probably worth summarizing the existing methods and typical biological applications that have been demonstrated in recent years. In brief, this overview will be split into three parts. First, we will summarize the typical approaches toward the synthesis of s-tetrazines till now. Then, we will provide the representative bio-orthogonal reactions by the combination of s-tetrazines with unsaturated compounds under physiological conditions. Eventually, we will propose a direction for the practical and efficient synthesis of s-tetrazine.
Chemotherapy is one of major interventions against cancer. However, the therapeutic outcome is commonly unsatisfactory and more agents are required. Natural compounds provide a large pool of candidates for drug development. Periplogenin, levistolide A and scutellarin are chemically defined compounds derived from different herbs that have been used in China for treating cancer for long. In the present study, we investigated their anti-cancer effects in vitro and in vivo using HCT116 colon cancer cells as an experimental model. Both periplogenein and lesvitolide A inhibited cancer cell viability in a dose- and time-dependent manner, and caused apoptosis via ROS and ER stress pathways. They showed combinational effects in the induction of apoptosis, when used in combination with 5-fluorouracil or oxaliplatin. Scutellarin neither affect the cell viability nor triggered apoptosis of the cancer cell. However, it sensitized the cancer cells to apoptosis induced by 5-fluorouracil. In nude mice, periplogenein and lesvitolide A inhibited the cancer cell growth substantially when used alone. They also showed combinational growth inhibition effects when used in combination with 5-fluorouracil. In contract, scutellarin did not sensitize the cancer cells to the growth inhibitory effect of 5-fluorouacial or oxaliplatin. In conclusion, our results showed that periplogenein and lesvitolide A inhibited the colon cancer cell growth in vitro and in vivo, when used alone or in combination with clinical drugs, suggesting that they are candidates for colon cancer chemotherapeutic development.
Abstract We report here a chemically synthetic method to introduce a PinB‐modified thymidine into well‐defined DNA first. The modification was designed to disturb the T−A base‐pairing, thus regulate the DNA activity for PCR amplification. By treatment with small molecules, i. e., reactive oxygen species, the DNA polymerase activity was successfully restored. Due to tight temporal regulation and cell‐membrane permeability, our approach could lead to application potential in live cell.
In living organisms, RNA regulates gene expression, cell migration, differentiation, and cell death. 5-Methylcytosine is a post-transcriptional RNA modification in a wide range of RNA species, including messenger RNAs. The addition of m5C to RNA cytosines is enabled by the NSUN enzyme family, a critical RNA methyltransferase. In this study, natural lysines modified with special groups were synthesized. Through two rounds of positive screening and one round of negative screening, we evaluated and identified the MbPylRS-tRNACUA unnatural lysine substitution system, which specifically recognizes lysine with a defined group. Moreover, non-natural lysine substitution at C271 of NSUN2 active site and the subsequent fluorescent labeling was realized through the click reaction. Then, the function of the NSUN2 mutant and its upregulated CDK1 gene as well as its effect on cell proliferation were evaluated. Efficient labeling and regulation of NSUN2 was achieved, laying the basis for further studies on the function and regulatory mechanism of upregulated genes.
ABSTRACT RNA plays a critical role in gene expression regulation, cell migration, differentiation, cell death in living organism. 5-Methylcytosine is a post transcriptional RNA modification identified across wide ranges of RNA species including message RNAs. It is reported the addition of m 5 C to RNA cytosines is enabled by use of NSUN family enzyme, NSUN2 is identified as a critical RNA methyltransferase for adding m 5 C to mRNA. We demonstrated here that natural lysines modified with special groups were synthesized via chemical synthesis. Through two rounds of positive screening and one round of negative screening, MbPylRS-tRNAcua unnatural lysine substitution system which can specifically recognize lysine with defined group was evaluated and identified. Non-natural lysine substitution at C271 of NSUN2 active site and subsequently fluorescent labeling was realized via so-called click reaction. The function of NSUN2 mutant and its upregulated CDK1 gene and its effect on cell proliferation were also evaluated.
Hexavalent chromium is classified as one of the group one carcinogens in 2012 by the IARC. Accumulated evidence indicates that centrosome amplification is sufficient to initiation tumorigenesis. Since chromium can cause centrosome amplification, it is logical to suspect that chromium causes tumorigenesis via centrosome amplification. The present study investigated the molecular mechanisms underlying chromium-elicited centrosome amplification using non-cancerous lung cells as an experimental model. We found that hexavalent chromium K2Cr2O7 was sub-toxic the cells at the concentration of 0.5 µM or below. At the sub-toxic concentrations, it induced centrosome amplification significantly. Treatment of the cells by chromium increased the intracellular level of reactive oxygen species (ROS), activated ATF-6, and increased the protein level of PLK4. Antioxidant N-acetylcysteine was able to inhibit the chromium-triggered ROS, ATF-6 activation, increment in PLK expression and centrosome amplification. Knockdown of ATF-6 inhibited the production of AFT6 active fragment, the PLK4 expression and centrosome amplification by chromium, without affecting the chromium-produced ROS. Knockdown of PLK4 inhibited the centrosome amplification, but did not modify the ROS production and AFT6 activation. In conclusion, our results suggest that the hexavalent chromium evokes centrosome amplification via ROS-ATF-6-PLK4 signaling pathways. Understanding the molecular mechanisms underlying the chromium-induced centrosome amplification is helpful for the assessment of centrosome amplification in the chromium-caused tumorigenesis.
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