HCCR-1 is a Novel Prognostic Indicator for Gastric Cancer and Promotes Cell Proliferation

mir-605-3p prevents liver premetastatic niche formation by inhibiting angiogenesis via decreasing exosomal nos3 release in gastric cancer

BACKGROUND

Cancer-induced pre-metastatic niches (PMNs) play a decisive role in promoting metastasis by facilitating angiogenesis in distant sites. Evidence accumulates suggesting that microRNAs (miRNAs) exert significant influence on angiogenesis during PMN formation, yet their specific roles and regulatory mechanisms in gastric cancer (GC) remain underexplored.

METHODS

miR-605-3p was identified through miRNA-seq and validated by qRT-PCR. Its correlation with the clinicopathological characteristics and prognosis was analyzed in GC. Functional assays were performed to examine angiogenesis both in vitro and in vivo. The related molecular mechanisms were elucidated using RNA-seq, immunofluorescence, transmission electron microscopy, nanoparticle tracking analysis, enzyme-linked immunosorbent assay, luciferase reporter assays and bioinformatics analysis.

RESULTS

miR-605-3p was screened as a candidate miRNA that may regulate angiogenesis in GC. Low expression of miR-605-3p is associated with shorter overall survival and disease-free survival in GC. miR-605-3p-mediated GC-secreted exosomes regulate angiogenesis by regulating exosomal nitric oxide synthase 3 (NOS3) derived from GC cells. Mechanistically, miR-605-3p reduced the secretion of exosomes by inhibiting vesicle-associated membrane protein 3 (VAMP3) expression and affects the transport of multivesicular bodies to the GC cell membrane. At the same time, miR-605-3p reduces NOS3 levels in exosomes by inhibiting the expression of intracellular NOS3. Upon uptake of GC cell-derived exosomal NOS3, human umbilical vein endothelial cells exhibited increased nitric oxide levels, which induced angiogenesis, established liver PMN and ultimately promoted the occurrence of liver metastasis. Furthermore, a high level of plasma exosomal NOS3 was clinically associated with metastasis in GC patients.

CONCLUSIONS

miR-605-3p may play a pivotal role in regulating VAMP3-mediated secretion of exosomal NOS3, thereby affecting the formation of GC PMN and thus inhibiting GC metastasis.

ECHDC2 inhibits the proliferation of gastric cancer cells by binding with NEDD4 to degrade MCCC2 and reduce aerobic glycolysis

BACKGROUND

The Enoyl-CoA hydratase/isomerase family plays a crucial role in the metabolism of tumors, being crucial for maintaining the energy balance and biosynthetic needs of cancer cells. However, the enzymes within this family that are pivotal in gastric cancer (GC) remain unclear.

METHODS

We employed bioinformatics techniques to identify key Enoyl-CoA hydratase/isomerase in GC. The expression of ECHDC2 and its clinical significance were validated through tissue microarray analysis. The role of ECHDC2 in GC was further assessed using colony formation assays, CCK8 assay, EDU assay, Glucose and lactic acid assay, and subcutaneous tumor experiments in nude mice. The mechanism of action of ECHDC2 was validated through Western blotting, Co-immunoprecipitation, and immunofluorescence experiments.

RESULTS

Our analysis of multiple datasets indicates that low expression of ECHDC2 in GC is significantly associated with poor prognosis. Overexpression of ECHDC2 notably inhibits aerobic glycolysis and proliferation of GC cells both in vivo and in vitro. Further experiments revealed that overexpression of ECHDC2 suppresses the P38 MAPK pathway by inhibiting the protein level of MCCC2, thereby restraining glycolysis and proliferation in GC cells. Ultimately, it was discovered that ECHDC2 promotes the ubiquitination and subsequent degradation of MCCC2 protein by binding with NEDD4.

CONCLUSIONS

These findings underscore the pivotal role of the ECHDC2 in regulating aerobic glycolysis and proliferation in GC cells, suggesting ECHDC2 as a potential therapeutic target in GC.

LETMD1, a target of KLF4, hinders endothelial inflammation and pyroptosis: A protective mechanism in the pathogenesis of atherosclerosis

Atherosclerosis (AS), a metabolic disorder, is usually caused by chronic inflammation. LETM1 Domain-Containing Protein 1 (LETMD1) is a mitochondrial outer membrane protein required for mitochondrial structure. This study aims to evaluate the functional role of LETMD1 in endothelial pathogenesis of AS. Oxidized low-density lipoprotein (ox-LDL)-induced human umbilical vein endothelial cells (HUVECs) and high-fat diet apolipoprotein E-deficient (ApoE-/-) mice were used to establish in vitro and in vivo models, respectively. Recombinant adenovirus vectors were constructed to investigate the role of LETMD1 in AS. mRNA sequencing was used to explore the effect of LETMD1 overexpression on gene expression in ox-LDL-induced HUVECs. A dual-luciferase reporting assay and chromatin immunoprecipitation (ChIP)-PCR were further conducted to verify the relationship between KLF4 and LETMD1. Results showed that LETMD1 was highly expressed in the aortas of atherosclerotic animals. LETMD1 overexpression reduced the expression of inflammatory factors, pyroptosis, ROS production, and NF-κB activation in ox-LDL-induced HUVECs, whereas LETMD1 knockdown had the opposite impact. LETMD1 overexpression was involved in regulating gene expression in ox-LDL-induced HUVECs. Overexpression of LETMD1 in mice reduced serum lipid levels as well as atherosclerotic lesions in the aortic roots. Furthermore, LETMD1 overexpression suppressed inflammatory reactions, cell pyroptosis, nuclear p65 protein level, cell apoptosis, and ROS generation in the aortas of AS mice. KLF4 (Krüppel-like factor 4) was found to be the transcriptional regulator of LETMD1. In conclusion, LETMD1, a target of KLF4, hinders endothelial inflammation and pyroptosis, which is a mechanism inhibiting the development of atherosclerosis.

Mitochondrial matrix protein LETMD1 maintains thermogenic capacity of brown adipose tissue in male mice

Brown adipose tissue (BAT) has abundant mitochondria with the unique capability of generating heat via uncoupled respiration. Mitochondrial uncoupling protein 1 (UCP1) is activated in BAT during cold stress and dissipates mitochondrial proton motive force generated by the electron transport chain to generate heat. However, other mitochondrial factors required for brown adipocyte respiration and thermogenesis under cold stress are largely unknown. Here, we show LETM1 domain-containing protein 1 (LETMD1) is a BAT-enriched and cold-induced protein required for cold-stimulated respiration and thermogenesis of BAT. Proximity labeling studies reveal that LETMD1 is a mitochondrial matrix protein. Letmd1 knockout male mice display aberrant BAT mitochondria and fail to carry out adaptive thermogenesis under cold stress. Letmd1 knockout BAT is deficient in oxidative phosphorylation (OXPHOS) complex proteins and has impaired mitochondrial respiration. In addition, BAT-specific Letmd1 deficient mice exhibit phenotypes identical to those observed in Letmd1 knockout mice. Collectively, we demonstrate that the BAT-enriched mitochondrial matrix protein LETMD1 plays a tissue-autonomous role that is essential for BAT mitochondrial function and thermogenesis.

Deletion of Letmd1 leads to the disruption of mitochondrial function in brown adipose tissue

Human cervical cancer oncogene (HCCR-1), also named as LETMD1, is an LETM-domain containing outer mitochondrial membrane protein which plays an important role in carcinogenesis. The present study found that the loss of Letmd1 in mice led to severe abnormities, such as brown adipose tissue (BAT) whitening, impaired thermogenesis of both BAT and beige fat, cold intolerance, diet-induced obesity, glucose intolerance and insulin resistance. Mechanically, the deletion of Letmd1 in BAT caused decreased level of both mitochondrial and intracellular Ca²⁺. The reduced intracellular Ca²⁺ could suppress the fission of mitochondria and ultimately lead to the disruption of BAT thermogenesis by regulating mitochondrial structures and functions. This study indicates that LETMD1 played a crucial role in BAT thermogenesis and energy homeostasis through regulating mitochondrial structures and functions, which provides a novel insight into therapeutic target exploration from oncogenes for metabolic disorders.

Identification of gastric cancer with convolutional neural networks: a systematic review

The identification of diseases is inseparable from artificial intelligence. As an important branch of artificial intelligence, convolutional neural networks play an important role in the identification of gastric cancer. We conducted a systematic review to summarize the current applications of convolutional neural networks in the gastric cancer identification. The original articles published in Embase, Cochrane Library, PubMed and Web of Science database were systematically retrieved according to relevant keywords. Data were extracted from published papers. A total of 27 articles were retrieved for the identification of gastric cancer using medical images. Among them, 19 articles were applied in endoscopic images and 8 articles were applied in pathological images. 16 studies explored the performance of gastric cancer detection, 7 studies explored the performance of gastric cancer classification, 2 studies reported the performance of gastric cancer segmentation and 2 studies analyzed the performance of gastric cancer delineating margins. The convolutional neural network structures involved in the research included AlexNet, ResNet, VGG, Inception, DenseNet and Deeplab, etc. The accuracy of studies was 77.3 - 98.7%. Good performances of the systems based on convolutional neural networks have been showed in the identification of gastric cancer. Artificial intelligence is expected to provide more accurate information and efficient judgments for doctors to diagnose diseases in clinical work.