Glutamine provides carbon and nitrogen to support the proliferation of cancer cells. However, the precise reason why cancer cells are particularly dependent on glutamine remains unclear. In this study, we report that glutamine modulates the tumor suppressor F-box and WD repeat domain-containing 7 (FBW7) to promote cancer cell proliferation and survival. Specifically, lysine 604 (K604) in the sixth of the 7 substrate-recruiting WD repeats of FBW7 undergoes glutaminylation (Gln-K604) by glutaminyl tRNA synthetase. Gln-K604 inhibits SCFFBW7-mediated degradation of c-Myc and Mcl-1, enhances glutamine utilization, and stimulates nucleotide and DNA biosynthesis through the activation of c-Myc. Additionally, Gln-K604 promotes resistance to apoptosis by activating Mcl-1. In contrast, SIRT1 deglutaminylates Gln-K604, thereby reversing its effects. Cancer cells lacking Gln-K604 exhibit overexpression of c-Myc and Mcl-1 and display resistance to chemotherapy-induced apoptosis. Silencing both c-MYC and MCL-1 in these cells sensitizes them to chemotherapy. These findings indicate that the glutamine-mediated signal via Gln-K604 is a key driver of cancer progression and suggest potential strategies for targeted cancer therapies based on varying Gln-K604 status.
Glutamine/metabolism* ; Myeloid Cell Leukemia Sequence 1 Protein/genetics* ; Humans ; Proto-Oncogene Proteins c-myc/genetics* ; Cell Proliferation ; Signal Transduction ; Neoplasms/pathology* ; F-Box-WD Repeat-Containing Protein 7/genetics* ; Cell Survival ; Cell Line, Tumor ; Apoptosis

Objectives: To investigate the prevalence and associated risk factors of tinnitus in Sichuan and Chongqing. Methods: We designed a tinnitus epidemiological questionnaire. The multi-stage stratified cluster random sampling methods was applied to obtain study subjects in six areas (Nanchong, Jiangjin, Fengdu, Yunyang, Suining and Ya'an), which were selected for epidemiological investigation. Home visit completion of epidemiological questionnaires was conducted. The trained investigators guided the respondents to fill in the tinnitus epidemiological questionnaires, and the epidemiological status of six areas on prevalence and risk factor was investigated. SPSS 22.0 software was used for statistical analysis. Results: Sampling population were 10 289, in which 9 273 were valid questionnaires. There were 4 281 males and 4 992 females, with an average age of 47.3 years, among which 34.83% (3 230/9 273) had tinnitus. 3.99% (370/9 273) were diagnosed with bothersome tinnitus. In a multivariable logistic regression mod, the following factors were associated with onsetting of tinnitus: sleep disorder [Odds Ratio(OR)=3.74] and noise exposure(OR=1.99). The risk of disease was lowest in the age of 30-40 years old, while the risk of disease was higher for people under 30 and over 40. In another multivariable logistic regression mode, the following factors were associated with having bothersome tinnitus: older people were more likely to suffer from tinnitus, sleep disorders (OR=4.68) and noise exposure (OR=1.56). Conclusions: The prevalence of tinnitus in Sichuan and Chongqing is about 34.83%, but most of the tinnitus is short-lived and has low loudness, which will not affect the patients. Only a small number of patients with tinnitus (3.99%) persist and affect their health and need treatment. The occurrence and exacerbation of tinnitus may be related to sleep, age, and noise exposure.
Adult ; Aged ; Female ; Humans ; Logistic Models ; Male ; Middle Aged ; Prevalence ; Risk Factors ; Surveys and Questionnaires ; Tinnitus/epidemiology*