Abstract 292: Identification of new components of the mTOR signaling pathway in pancreatic cancer cells by a genome-wide RNAi screen

Aim. Pancreatic cancer is one of the most quickly fatal cancers around the world. Burgeoning researches have begun to prove that mitochondria play a crucial role in cancer treatment. Mitofusin2 (Mfn2) plays an indispensable role in mitochondrial fusion and adjusting function. However, the role and underlying mechanisms of Mfn2 on cell autophagy of pancreatic cancer is still unclear. Our aim was to explore the effect of Mfn2 on multiple biological functions involving cell autophagy in pancreatic cancer. Methods. Pancreatic cancer cell line, Aspc-1, was treated with Ad-Mfn2 overexpression. Western blotting, caspase-3 activity measurement, and CCK-8 and reactive oxygen species (ROS) assay were used to examine the effects of Mfn2 on pancreatic cancer autophagy, apoptosis, cell proliferation, oxidative stress, and PI3K/Akt/mTOR signaling. The expression of tissue Mfn2 was detected by immunohistochemical staining. Survival analysis of Mfn2 was evaluated by OncoLnc. Results. Mfn2 improved the expression of LC3-II and Bax and downregulated the expression of P62 and Bcl-2 in pancreatic cancer cells. Meanwhile, Mfn2 also significantly inhibited the expression of p-PI3K, p-Akt, and p-mTOR proteins in pancreatic cancer cells. In addition, Mfn2 inhibited pancreatic cancer cell proliferation and ROS production. Assessment of Kaplan-Meier curves showed that Mfn2− pancreatic cancer has a worse prognosis than Mfn2+ pancreatic cancer has. Conclusions. Our finding suggests that Mfn2 induces cell autophagy of pancreatic cancer through inhibiting the PI3K/Akt/mTOR signaling pathway. Meanwhile, Mfn2 also influences multiple biological functions of pancreatic cancer cells. Mfn2 may act as a therapeutic target in pancreatic cancer treatment.

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Kaempferol induces ROS-dependent apoptosis in pancreatic cancer cells via TGM2-mediated Akt/mTOR signaling

BMC Cancer ◽

10.1186/s12885-021-08158-z ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Fengjiao Wang ◽

Lai Wang ◽

Chao Qu ◽

Lianyu Chen ◽

Yawen Geng ◽

...

Keyword(s):

Pancreatic Cancer ◽

Cancer Cells ◽

Signaling Pathway ◽

Colony Formation ◽

Mtor Signaling ◽

Mrna Levels ◽

Apoptotic Signaling ◽

Pancreatic Cancer Cells ◽

Public Data

Abstract Background Kaempferol, a natural flavonoid, exhibits anticancer properties by scavenging reactive oxygen species (ROS). However, increasing evidence has demonstrated that, under certain conditions, kaempferol can inhibit tumor growth by upregulating ROS levels. In this study, we aimed to investigate whether kaempferol effectively suppresses pancreatic cancer through upregulation of ROS, and to explore the underlying molecular mechanism. Methods PANC-1 and Mia PaCa-2 cells were exposed to different concentrations of kaempferol. Cell proliferation and colony formation were evaluated by CCK-8 and colony formation assays. Flow cytometry was performed to assess the ROS levels and cell apoptosis. The mRNA sequencing and KEGG enrichment analysis were performed to identify differentially expressed genes and to reveal significantly enriched signaling pathways in response to kaempferol treatment. Based on biological analysis, we hypothesized that tissue transglutaminase (TGM2) gene was an essential target for kaempferol to induce ROS-related apoptosis in pancreatic cancer. TGM2 was overexpressed by lentivirus vector to verify the effect of TGM2 on the ROS-associated apoptotic signaling pathway. Western blot and qRT-PCR were used to determine the protein and mRNA levels, respectively. The prognostic value of TGM2 was analyzed by Gene Expression Profiling Interactive Analysis (GEPIA) tools based on public data from the TCGA database. Results Kaempferol effectively suppressed pancreatic cancer in vitro and in vivo. Kaempferol promoted apoptosis in vitro by increasing ROS generation, which was involved in Akt/mTOR signaling. TGM2 levels were significantly increased in PDAC tissues compared with normal tissues, and high TGM2 expression was positively correlated with poor prognosis in pancreatic cancer patients. Decreased TGM2 mRNA and protein levels were observed in the cells after treatment with kaempferol. Additionally, TGM2 overexpression downregulated ROS production and inhibited the abovementioned apoptotic signaling pathway. Conclusions Kaempferol induces ROS-dependent apoptosis in pancreatic cancer cells via TGM2-mediated Akt/mTOR signaling, and TGM2 may represent a promising prognostic biomarker for pancreatic cancer.

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