Yang Luo

Abstract Background N 6 -methyladenosine (m 6 A) emerges as one of the most important modification of RNA. Bladder cancer is a common cancer type in developed countries, and hundreds of thousands of bladder cancer patients die every year. Materials and methods There are various cells in bladder tumor bulk, and a small population cells defined as tumor initiating cells (TIC) have self-renewal and differentiation capacities. Bladder TICs drive bladder tumorigenesis and metastasis, and their activities are fine regulated. However, the role of N 6 -methyladenosine in bladder TIC self-renewal is unknown. Results Here, we found a decrease of N 6 -methyladenosine in bladder tumors and bladder TICs. N 6 -methyladenosine levels are related to clinical severity and outcome. Mettl14 is lowly expressed in bladder cancer and bladder TICs. Mettl14 knockout promotes the proliferation, self-renewal, metastasis and tumor initiating capacity of bladder TICs, and Mettl14 overexpression exerts an opposite role. Mettl14 and m 6 A modification participate in the RNA stability of Notch1 mRNA. Notch1 m 6 A modification inhibits its RNA stability. Notch1 plays an essential role in bladder tumorigenesis and bladder TIC self-renewal. Conclusion This work reveals a novel role of Mettl14 and N 6 -methyladenosine in bladder tumorigenesis and bladder TICs, adding new layers for bladder TIC regulation and N 6 -methyladenosine function.

Testicular germ cell tumors (TGCTs) are highly prevalent in young men aged 20-40 years and are one of the most common lethal solid tumors in men of this age. Due to the current unclear mechanism of tumor development, there is a lack of effective treatment, and therefore in-depth research of the molecular mechanism of the occurrence and development of TGCT and the search for suitable and effective therapeutic targets and molecular markers are of great significance for achieving effective treatment. METTL3 is a very important methylase, which has been implicated in the progression of many cancers, but the role of METTL3 in TGCT has not been fully elucidated. In this article, we found that METTL3 expression was significantly downregulated in TGCT tissues, and patients with low expression levels had lower overall survival and relapse-free survival rates. After overexpressing METTL3, cell proliferation, invasion, and migration ability significantly increased, while influencing the expression of epithelial-mesenchymal transition (EMT)-related proteins. In addition, we observed that the expression level of METTL3 positively correlated with molecular markers and infiltration level of CD8+ and CD4+ T cells and natural killer cells. In sum, our findings identified that METTL3 can be used as an independent prognostic marker in patients with TGCT. METTL3 participates in the proliferation, migration, and invasion of TGCT cells by regulating the expression of EMT-related genes and may also play a role in activating the tumor immune response in TGCT.

OBJECTIVE: To determine whether lysosome-associated protein transmembrane-4 beta (LAPTM4B) over-expression is associated with the proliferation and invasion in colorectal cancer (CRC). METHODS: Thirty pairs of CRC tissues, containing carcinoma and adjacent tissues, were used for the examination of LAPTM4B mRNA expression by real-time quantitative PCR (qPCR) assays. Then immunohistochemistry was performed to examine LAPTM4B protein expression in 6 pairs of CRC tissues. Over-expression LAPTM4B and low-expression LAPTM4B cell models were constructed with HCT116 CRC cell lines. CCK8 assay was used to detect the proliferation and Transwell assay was used to detect the invasion of the model cells. RESULTS: qPCR and immunohistochemistry results showed that LAPTM4B expression levels in CRC were higher compared to adjacent tissues (all P<0.01). CCK8 and Transwell assays results showed that LAPTM4B promoted proliferation and invasion of HCT116 cell lines model cells (all P<0.01). CONCLUSION: LAPTM4B promotes the proliferation and invasion in CRC patients, and may be used as an important potential marker.

OBJECTIVE: Ribonucleotide reductase subunit M1 (RRM1) is the intracellular target of gemcitabine (GEM). The aim of this study is to explore the relationship between the level of RRM1 expression and the sensitivity to GEM in the esophageal squamous cell carcinoma cell lines. METHODS: Four esophageal squamous cell carcinoma cell lines (Kyse-150, Kyse-450, 9706 and Eca-109) were cultured in vitro. In the same period, RRM1 expression level was measured by RT-PCR and Western blot, and cell sensitivity to GEM was determined by CCK-8 assay. The relation between cell sensitivity and RRM1 expression was further analyzed. Kyse-450 cells were continuously cultured in the medium containing 50 nM GEM. RRM1 expression was measured at different time points to monitor the dynamic changes in the surviving cells. Inhibition of RRM1 expression by RNAi method was applied and the effect on GEM-sensitivity was further examined. RESULTS: The IC(50) of Eca-109, Kyse-150, Kyse-450 and 9706 cells were (0.92 +/- 0.17), (0.48 +/- 0.11), (0.29 +/- 0.06) and (0.02 +/- 0.01) mmol/L, respectively. The expressions of RRM1 protein and mRNA of Eca-109 cell line were the highest detected by Western blot and RT-PCR, followed by Kyse-150 and Kyse-450, and the lowest one was 9706 cell line. When Kyse-450 cells were continuously treated with 50 nmol/L GEM, the level of RRM1 protein was increasing in the surviving cells. RRM1 siRNA could effectively knock down the expression of RRM1 and significantly increase the cell sensitivity to GEM (P = 0.035). CONCLUSION: The level of RRM1 expression correlates with the cell sensitivity to gemcitabine. The cells with a lower level of RRM1 expression are more sensitive to gemcitabine.