Fusobacterium nucleatum promotes esophageal squamous cell carcinoma progression and chemoresistance by enhancing the secretion of chemotherapy-induced senescence-associated secretory phenotype via activation of DNA damage response pathway.

Senescence frequently occurs in cancer cells in response to chemotherapy (called therapy-induced senescence). Senescent cells can exert paracrine effects through the senescence-associated secretory phenotype (SASP) promoting cancer recurrence and chemoresistance. The altered gut microbiota has been closely associated with cancer progression through the direct interaction with cancer cells. However, little is known about the relationship between the gut microbiota and therapy-induced senescent cells. This study aimed to explore the impact of the gut microbiota on therapy-induced senescent cells and the SASP. We found that esophageal squamous cell carcinoma (ESCC) cells were induced into senescence following platinum-based chemotherapy, accompanied by the secretion of a robust SASP. Furthermore, senescent ESCC cells exerted a tumor-promoting effect through the SASP both in vitro and in vivo. Through 16S rRNA gene sequencing and fluorescence in situ hybridization, we identified that Fusobacterium nucleatum (F. nucleatum) was abundant in human ESCC cancerous tissues and correlated with poor prognosis in ESCC patients. Notably, F. nucleatum further promoted the secretion of the SASP by senescent ESCC cells. Compared with the conditioned medium from senescent ESCC cells, the conditioned medium from F. nucleatum-treated senescent ESCC cells accelerated tumor growth in xenograft models, enhanced migration and invasion abilities, and potentiated chemoresistance both in vitro and in vivo. Mechanistically, F. nucleatum invaded and survived in senescent ESCC cells and induced an increase in DNA damage to further activate the DNA damage response pathway, thus enhancing the SASP. Altogether, these findings reveal for the first time that F. nucleatum promotes the secretion of chemotherapy-induced SASP to drive ESCC progression and chemoresistance, which supports F. nucleatum as a potential target for ESCC therapy.

Targeting mitochondrial transcription factor A sensitizes pancreatic cancer cell to gemcitabine.

BACKGROUND: The survival of pancreatic cancer cells, particularly cancer stem cells which are responsible for tumor relapse, depends on mitochondrial function. Mitochondrial transcription factor A (TFAM) is critical for the regulation of mitochondrial DNA and thus mitochondrial function. However, the possible involvement of TFAM in pancreatic cancer is unknown. METHODS: Human samples were obtained from pancreatic cancers and their adjacent tissues; human pancreatic cell lines were cultured in RPMI1640 medium. TFAM expressions in pancreatic tissues and cultured cells were determined using immunohistochemistry, ELISA, and reverse transcription polymerase chain reaction (RT-PCR). The effect of TFAM on cell growth, migration, colony formation and apoptosis were evaluated. Mitochondrial biogenesis in pancreatic cancer and normal cells were examined. RESULTS: The majority of pancreatic cancer tissues exhibited higher TFAM expression compared to the adjacent counterparts. Consistently, TFAM mRNA and protein levels were higher in pancreatic cancer cell lines than in immortalized normal pancreatic epithelial cells. There was no difference on TFAM level between gemcitabine-sensitive and resistant pancreatic cancer cells. Functional analysis demonstrated that TFAM overexpression activated pancreatic normal and tumor cells whereas TFAM inhibition effectively inhibited the growth of pancreatic cancer cells. TFAM inhibition enhanced gemcitabine's cytotoxicity and suppressed growth, anchorage-independent colony formation and survival of gemcitabine-resistant pancreatic cancer cells. Mechanistic studies showed that TFAM inhibition resulted in remarkable mitochondrial dysfunction and energy crisis followed by oxidative stress. The basal mitochondrial biogenesis level correlated well with TFAM level in pancreatic cancer cells. CONCLUSIONS: TFAM played essential roles in pancreatic cancer via regulating mitochondrial functions which highlighted the therapeutic value of inhibiting TFAM to overcome gemcitabine resistance.

Clinical characteristics of patients with 2019 coronavirus disease in a non-Wuhan area of Hubei Province, China: a retrospective study.

BACKGROUND: Since December 2019, the 2019 coronavirus disease (COVID-19) has expanded to cause a worldwide outbreak that more than 600,000 people infected and tens of thousands died. To date, the clinical characteristics of COVID-19 patients in the non-Wuhan areas of Hubei Province in China have not been described. METHODS: We retrospectively analyzed the clinical characteristics and treatment progress of 91 patients diagnosed with COVID-19 in Jingzhou Central Hospital. RESULTS: Of the 91 patients diagnosed with COVID-19, 30 cases (33.0%) were severe and two patients (2.2%) died. The severe disease group tended to be older (50.5 vs. 42.0 years; p = 0.049) and have more chronic disease (40% vs. 14.8%; p = 0.009) relative to mild disease group. Only 73.6% of the patients were quantitative polymerase chain reaction (qPCR)-positive on their first tests, while typical chest computed tomography images were obtained for each patient. The most common complaints were cough (n = 75; 82.4%), fever (n = 59; 64.8%), fatigue (n = 35; 38.5%), and diarrhea (n = 14; 15.4%). Non-respiratory injury was identified by elevated levels of aspartate aminotransferase (n = 18; 19.8%), creatinine (n = 5; 5.5%), and creatine kinase (n = 14; 15.4%) in laboratory tests. Twenty-eight cases (30.8%) suffered non-respiratory injury, including 50% of the critically ill patients and 21.3% of the mild patients. CONCLUSIONS: Overall, the mortality rate of patients in Jingzhou was lower than that of Wuhan. Importantly, we found liver, kidney, digestive tract, and heart injuries in COVID-19 cases besides respiratory problems. Combining chest computed tomography images with the qPCR analysis of throat swab samples can improve the accuracy of COVID-19 diagnosis.