SMAGP a novel biomarker of cervical cancer development and progression

MAVI1, an endoplasmic reticulum-localized microprotein, suppresses antiviral innate immune response by targeting MAVS on mitochondrion

Pattern recognition receptor-mediated innate immunity is critical for host defense against viruses. A growing number of coding and noncoding genes are found to encode microproteins. However, the landscape and functions of microproteins in responsive to virus infection remain uncharacterized. Here, we systematically identified microproteins that are responsive to vesicular stomatitis virus infection. A conserved and endoplasmic reticulum-localized membrane microprotein, MAVI1 (microprotein in antiviral immunity 1), was found to interact with mitochondrion-localized MAVS protein and inhibit MAVS aggregation and type I interferon signaling activation. The importance of MAVI1 was highlighted that viral infection was attenuated and survival rate was increased in Mavi1-knockout mice. A peptide inhibitor targeting the interaction between MAVI1 and MAVS activated the type I interferon signaling to defend viral infection. Our findings uncovered that microproteins play critical roles in regulating antiviral innate immune responses, and targeting microproteins might represent a therapeutic avenue for treating viral infection.

SMAGP regulates doxorubicin sensitivity in triple-negative breast cancer cells via modulating mitochondrial respiration

Doxorubicin-based chemotherapy remains as a major therapeutic approach for patients with triple-negative breast cancer (TNBC). However, insensitivity or resistance to doxorubicin treatment limits the therapeutic efficacy. Mitochondrial respiration plays a critical role in regulating the sensitivity of cancer cells to chemotherapy drugs. Here, we found that small trans-membrane and glycosylated protein (SMAGP) is upregulated in TNBC cells in comparison to normal breast and other subtypes of breast cancer cells. High SMAGP expression is associated with poorer overall survival of TNBC patients. Importantly, loss of SMAGP enhanced the sensitivity of TNBC cells to doxorubicin treatment. Mechanistically, we detected a functional pool of SMAGP in the mitochondria of TNBC cells controlling doxorubicin sensitivity via regulating mitochondrial respiration. Thus, our data suggest that SMAGP acts as a novel regulator of doxorubicin sensitivity in TNBC, identifying SMAGP as a promising therapeutic target for improving the efficacy of doxorubicin-based chemotherapy in TNBC patients.

CD8+ T Cell-Associated Gene Signature Correlates With Prognosis Risk and Immunotherapy Response in Patients With Lung Adenocarcinoma

The presence of infiltrating CD8⁺ T lymphocytes in the tumor microenvironment of lung adenocarcinoma (LUAD) is correlated with improved patient prognosis, but underlying regulatory mechanisms remain unknown. To identify biomarkers to improve early diagnosis and treatment of LUAD, we downloaded 13 immune cell line-associated datasets from the GEO database. We identified CD8⁺ T cell-associated genes via weighted correlation network analysis. We constructed molecular subtypes based on CD8⁺ T cell-associated genes and constructed a multi-gene signature. We identified 252 CD8⁺ T cell-associated genes significantly enriched in immune function-related pathways and two molecular subtypes of LUAD (immune cluster 1 [IC1] and IC2) using our CD8⁺ T cell-associated gene signature. Patients with the IC2 subtype had a higher tumor mutation burden and lower immune infiltration scores, whereas those with the IC1 subtype were more sensitive to immune checkpoint inhibitors. Prioritizing the top candidate genes to construct a 10-gene signature, we validated our model using independent GSE and TCGA datasets to confirm its robustness and stable prognostic ability. Our risk model demonstrated good predictive efficacy using the Imvigor210 immunotherapy dataset. Thus, we established a novel and robust CD8⁺ T cell-associated gene signature, which could help assess prognostic risk and immunotherapy response in LUAD patients.

SMAGP knockdown inhibits the malignant phenotypes of glioblastoma cells by inactivating the PI3K/Akt pathway

Small trans-membrane and glycosylated protein (SMAGP), a novel small trans-membrane glycoprotein, is reported to be upregulated in multiple cancers and involved in tumor development. However, little is known about its role in the development of glioblastoma (GBM). GEPIA database was used to analyze SMAGP expression and evaluate the prognostic value of SMAGP in GBM. GO and KEGG pathway enrichment analyses were used to predict the biological functions and pathways of SMAGP and 948 SMAGP-correlated genes using DAVID database. Cell viability, colony formation ability, apoptosis, and invasion were evaluated by MTT, colony formation assay, flow cytometry analysis, and Transwell invasion assay, respectively. Western blot was applied to detect the expression of SMAGP, matrix metalloproteinase (MMP)-2, and MMP-9 and analyze the changes of phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling. Results showed that SMAGP was upregulated and correlated with poor prognosis in GBM. Functional annotation analysis revealed that SMAGP and 948 SMAGP-correlated genes were primarily associated with cell adhesion and PI3K/Akt pathway. SMAGP interference inhibited cell viability and colony formation ability and promoted apoptosis in GBM cells. Moreover, SMAGP interference inhibited GBM cell invasion and suppressed MMP-2 and MMP-9 expression. Additionally, SMAGP silencing inhibited the PI3K/Akt pathway in GBM cells. Overexpression of Akt abolished the effects of SMAGP knockdown on the malignant phenotypes of GBM cells. In conclusion, SMAGP silencing inhibited the malignant phenotypes of GBM cells by inactivating the PI3K/Akt pathway.

GPX2 suppression of H2O2 stress regulates cervical cancer metastasis and apoptosis via activation of the β-catenin-WNT pathway

BACKGROUND

Increasing evidence suggests that glutathione peroxidase 2 (GPX2) plays important roles in the tumorigenesis and progression of various human cancers, such as colorectal carcinomas and lung adenocarcinomas. However, the role of GPX2 in cervical cancer is unclear. In this study, we identified the role of GPX2 in cervical cancer tissues and cell lines.

MATERIALS AND METHODS

The basal mRNA and protein expression of GPX2 in cervical cancer cells and a series of key molecules in the epithelial to mesenchymal transition (EMT) and WNT/β-catenin pathways were examined via real time fluorescence quantitative PCR (qRT-PCR) and Western blot assays. The biological phenotype of the cervical cancer cell lines was detected by the cloning formation and transwell assays, and intracellular reactive oxygen species (ROS) levels were detected by flow cytometry. Finally, the GPX2 expression level in 100 clinical cervical tissues was examined by immunohistochemistry.

RESULTS

We found that GPX2 was highly expressed in cervical cancer tissues compared to normal individuals and promoted the proliferation and metastasis of cervical cancer cells, and this promotion correlated with the activation of EMT and WNT/β-catenin signaling in vitro. GPX2 was determined to reduce apoptotic damage by reducing hydroperoxides. According to the characteristics and verification of GPX2, this series of phenotypes is clearly related to oxidative stress in cells. Furthermore, we verified that GPX2 was highly expressed in cervical cancer tissues and promoted the metastasis of cervical cancer.

CONCLUSION

In summary, we found that GPX2 was highly expressed in cervical cancer cells and promoted the proliferation and metastasis of cervical cancer by affecting oxidative stress. Our study provides a new target for the clinical treatment of cervical cancer.