Clinical values of Ku80 upregulation in superficial esophageal squamous cell carcinoma

LSD1 regulates the FOXF2-mediated Wnt/β-catenin signaling pathway by interacting with Ku80 to promote colon cancer progression

Lysine-specific demethylase 1 (LSD1) is widely involved in the proliferation, invasion, and metastasis of cancers. However, it is uncertain whether LSD1 plays a role in facilitating colon cancer progression. Here, we have clarified the molecular mechanism by which LSD1 interacts with X-ray repair cross complementing protein 5 (Ku80) to promote colon cancer progression by directly targeting forehead protein transcription factor 2 (FOXF2). First, the interacting proteins of LSD1 were identified by immunoprecipitation and mass spectrometry. The expression of Ku80 and FOXF2 in colon cancer was detected using immunohistochemistry, real-time quantitative transcription polymerase chain reaction, and western blot. Next, the proliferation, invasion, and metastasis of colon cancer in vitro and in vivo were detected by methyl thiazolyl tetrazolium, 5-ethynyl-20-deoxyuridine, colony formation, wound healing, and nude mice xenograft model assays, respectively. Chromatin immunoprecipitation (ChIP) and ChIP-PCR were performed to investigate the molecular mechanism of LSD1 and Ku80 in colon cancer. Our results indicated that Ku80 expression was positively correlated with the invasion and migration of colon cancer cells, and negatively correlated with FOXF2 expression. More importantly, the high expression of Ku80 and the low expression of FOXF2 were particularly associated with driving the progression of colon cancer. Ku80 knockdown and LSD1 silencing inhibited the proliferation, migration, and invasion of colon cancer in vitro and in vivo. Mechanically, LSD1 interacts with Ku80 and also binds directly to the 687-887-bp portion of the FOXF2 promoter region. The upregulated methylation level of H3K4me2 in the FOXF2 promoter region facilitated the transcriptional activation of FOXF2, and downregulated protein expression associated with the Wnt/β-catenin signaling pathway. In conclusion, our study suggests that LSD1 regulates the FOXF2-mediated Wnt/β-catenin signaling pathway by interacting with Ku80, promoting the malignant biological properties of colon cancer, highlighting the binding of LSD1 and Ku80 as a useful anti-cancer target for colon cancer.

Interception of Signaling Circuits of Esophageal Adenocarcinoma Cells by Resveratrol Reveals Molecular and Immunomodulatory Signatures

Simple Summary

Adenocarcinoma of the esophagus has been on the rise lately. Increase in mortality due to a paucity of efficacious drugs for this cancer prompted us to discover molecular signatures to combat this malady. To this end, we chose resveratrol—a polyphenol and studied its impact on three esophageal adenocarcinoma cell lines (OE33, OE19 and FLO-1) by multilevel profiling. Here, we show the impact of resveratrol on the viability of the three cell systems studied, at the cellular, molecular level and by proteomic analysis. Impact on programmed cell death pathway resulting in an increase in apoptotic and caspase-positive cells were observed. Decrease in Bcl2. levels and impact on reactive oxygen species (ROS) was also observed. Moreover, proteomic profiling highlighted pivotal differentially regulated signaling molecules. Notably, the downregulation of Ku80 by resveratrol could be harnessed for chemo-radiation therapy to prevent DNA break repair after radiation therapy. Additionally, protein profiling has shed light on molecular and immune-modulatory signatures with implications for discovering novel treatments such as chemo-immunotherapy.

Abstract

Deregulation of signaling pathways due to mutations sets the cell on a path to neoplasia. Therefore, recent reports of increased mutations observed in esophageal tissue reflects the enhanced risk of tumor formation. In fact, adenocarcinoma of the esophagus has been on the rise lately. Increase in mortality due to a paucity of efficacious drugs for this cancer prompted us to discover molecular signatures to combat this malady. To this end, we chose resveratrol—a polyphenol with anticancer property—and studied its impact on three esophageal adenocarcinoma cell lines (OE33, OE19 and FLO-1) by multilevel profiling. Here, we show the impact of resveratrol on the viability of the three adenocarcinoma esophageal cell systems studied, at the cellular level. Furthermore, an analysis at the molecular level revealed that the action was through the programmed cell death pathway, resulting in an increase in apoptotic and caspase-positive cells. The impact on reactive oxygen species (ROS) and a decrease in Bcl2 levels were also observed. Moreover, proteomic profiling highlighted pivotal differentially regulated signaling molecules. The phenotypic effect observed in resveratrol-treated esophageal cells could be due to the stoichiometry per se of the fold changes observed in entities of key signaling pathways. Notably, the downregulation of Ku80 and other pivotal entities by resveratrol could be harnessed for chemo-radiation therapy to prevent DNA break repair after radiation therapy. Additionally, multilevel profiling has shed light on molecular and immune-modulatory signatures with implications for discovering novel treatments, including chemo-immunotherapy, for esophageal adenocarcinomas which are known to be aggressive cancers.

Deficiency of Ku Induces Host Cell Exploitation in Human Cancer Cells

Cancer metastasis is the major cause of death from cancer (Massague and Obenauf, 2016; Steeg, 2016). The extensive genetic heterogeneity and cellular plasticity of metastatic tumors set a prime barrier for the current cancer treatment protocols (Boumahdi and de Sauvage, 2020). In addition, acquired therapy resistance has become an insurmountable obstacle that abolishes the beneficial effects of numerous anti-cancer regimens (De Angelis et al., 2019; Boumahdi and de Sauvage, 2020). Here we report that deficiency of Ku leads to the exploitation of host cells in human cancer cell line models. We found that, upon conditional deletion of XRCC6 that codes for Ku70, HCT116 human colorectal cancer cells gain a parasitic lifestyle that is characterized by the continuous cycle of host cell exploitation. We also found that DAOY cells, a human medulloblastoma cell line, innately lack nuclear Ku70/Ku86 proteins and utilize the host-cell invasion/exit mechanism for maintenance of their survival, similarly to the Ku70 conditionally-null HCT116 cells. Our study demonstrates that a functional loss of Ku protein promotes an adaptive, opportunistic switch to a parasitic lifestyle in human cancer cells, providing evidence for a previously unknown mechanism of cell survival in response to severe genomic stress. We anticipate that our study will bring a new perspective for understanding the mechanisms of cancer cell evolution, leading to a shift in the current concepts of cancer therapy protocols directed to the prevention of cancer metastasis and therapy resistance.

Identification of a Ten-Gene Signature of DNA Damage Response Pathways with Prognostic Value in Esophageal Squamous Cell Carcinoma

Molecular prognostic signatures are critical for treatment decision-making in esophageal squamous cell cancer (ESCC), but the robustness of these signatures is limited. The aberrant DNA damage response (DDR) pathway may lead to the accumulation of mutations and thus accelerate tumor progression in ESCC. Given this, we applied the LASSO Cox regression to the transcriptomic data of DDR genes, and a prognostic DDR-related gene expression signature (DRGS) consisting of ten genes was constructed, including PARP3, POLB, XRCC5, MLH1, DMC1, GTF2H3, PER1, SMC5, TCEA1, and HERC2. The DRGS was independently associated with overall survival in both training and validation cohorts. The DRGS achieved higher accuracy than six previously reported multigene signatures for the prediction of prognosis in comparable cohorts. Furtherly, a nomogram incorporating DRGS and clinicopathological features showed improved predicting performance. Taken together, the DRGS was identified as a novel, robust, and effective prognostic indicator, which may refine the scheme of risk stratification and management in ESCC patients.