MPZL1 suppresses the cancer stem-like properties of lung cancer through ß-catenin/TCF4 signaling.

This study was designed to explore the influence of myelin protein zero-like protein 1 (MPZL1) on the stem-like properties of cancer cells and the underlying mechanism in lung adenocarcinoma. Real-time quantitative polymerase chain reaction (RT-qPCR) was utilized to evaluate mRNA expression level. CCK8, wound healing, and transwell assays were applied to assess cell proliferation, migration, and invasion. Tumorsphere-formation assay was utilized to assess cancer stem cell-like properties. LF3 was used to block the ß-catenin/Transcription factor 4 (TCF-4) signaling. Xenograft nude mouse model was conducted; tumor weight and volume were recorded. Western blot assay was utilized to detect the expression levels of CD44, CD133, ß-catenin, TCF-4, and MPZL1. Following MPZL1 knockdown, the mRNA expression levels of MPZL1, ß-catenin, and TCF-4 were inhibited, while the mRNA expression levels of the above genes were increased after the MPZL1 overexpression. MPZL1 knockdown suppressed cell proliferation, migration, and invasion, reduced the tumorsphere-formation capacity, and restrained the expression levels of CD44 and CD133. However, MPZL1 overexpression promoted the cell proliferation, migration, and invasion, enhanced the tumorsphere-formation capacity, and increased the expression levels of CD44 and CD133. Interestingly, LF3 treatment partially revised the effect of MPZL1 overexpression. These findings were further corroborated by in vivo experiments. We concluded that MPZL1 could suppress the lung adenocarcinoma cells' proliferation, migration, invasion, and lung cancer stem cells characteristics. The underlying mechanism is involved in the activation of ß-catenin/TCF-4 signaling.

MPZL1 Promotes Lung Adenocarcinoma Progression by Enhancing Tumor Proliferation, Invasion, Migration, and Suppressing Immune Function via Transforming Growth Factor-ß1.

Lung cancer (LC) is the leading cause of death worldwide, and lung adenocarcinoma (LUAD) is the most common form of LC. The abnormally high expression of myelin protein zero-like 1 (MPZL1) promotes the malignant progression of various tumors. However, there is no relevant report on the functional role of MPZL1 in LUAU. In this study, we applied Illumina sequencing to screen differentially expressed genes. Subsequently, MPZL1 was selected as hub gene for quantitative real-time polymerase chain reaction (qRT-PCR) and CCK8 assay. The expression level of MPZL1 was analyzed by immunohistochemistry, immunofluorescence, western blot, and qRT-PCR. After silencing or overexpressing MPZL1, CCK8, EDU, clone formation, scratch healing, invasion, and nude mouse tumor-bearing experiments were performed to detect the abilities of cell proliferation, migration, invasion, and tumorigenicity. Moreover, qRT-PCR, western blot, coimmunoprecipitation, and scratch healing assays were conducted to explore the transcriptional regulatory factors of MPZL1. Finally, the relationship between MPZL1 and immunotherapy was explored through public databases and validated in vivo. The results show that a total of 196 high-expressed genes and 496 low-expressed genes were screened. Differential genes are mainly enriched in cell proliferation and division, protein binding, and other pathways and functions. MPZL1 was selected as the hub gene and upregulated in LUAD tissues and cells. Silencing MPZL1 inhibited the cell proliferation and cloning formation, and the growth of tumor. Conversely, overexpression of MPZL1 has the opposite effect. In addition, MPZL1 combines with the transforming growth factor-ß1 to promote the progress of LUAD. Finally, we found that high expression of MPZL1 is negatively correlated with infiltration of CD8+ cells and may lead to immunotherapy resistance. In summary, this study revealed a new mechanism by which MPZL1 promotes LUAD progression by enhancing tumor proliferation, invasion, migration, and suppressing immune function.