Increased expression of REG3A promotes tumorigenic behavior in triple negative breast cancer cells.

Identifying new targets in triple negative breast cancer (TNBC) remains critical. REG3A (regenerating islet-derived protein 3 A), a calcium-dependent lectin protein, was thoroughly investigated for its expression and functions in breast cancer. Bioinformatics and local tissue analyses were employed to identify REG3A expression in breast cancer. Genetic techniques were employed to modify REG3A expression, and the resulting effects on the behaviors of breast cancer cells were examined. Subcutaneous xenograft models were established to investigate the involvement of REG3A in the in vivo growth of breast cancer cells. Analysis of the TCGA database uncovered increased REG3A levels in human breast cancer tissues. Additionally, REG3A mRNA and protein levels were elevated in TNBC tissues of locally treated patients, contrasting with low expression in adjacent normal tissues. In primary human TNBC cells REG3A shRNA notably hindered cell proliferation, migration, and invasion while triggering caspase-mediated apoptosis. Similarly, employing CRISPR-sgRNA for REG3A knockout showed significant anti-TNBC cell activity. Conversely, REG3A overexpression bolstered cell proliferation and migration. REG3A proved crucial for activating the Akt-mTOR cascade, as evidenced by decreased Akt-S6K1 phosphorylation upon REG3A silencing or knockout, which was reversed by REG3A overexpression. A constitutively active mutant S473D Akt1 (caAkt1) restored Akt-mTOR activation and counteracted the proliferation inhibition and apoptosis induced by REG3A knockdown in breast cancer cells. Crucially, REG3A played a key role in maintaining mTOR complex integrity. Bioinformatics identified zinc finger protein 680 (ZNF680) as a potential REG3A transcription factor. Knocking down or knocking out ZNF680 reduced REG3A expression, while its overexpression increased it in primary breast cancer cells. Additionally, enhanced binding between ZNF680 protein and the REG3A promoter was observed in breast cancer tissues and cells. In vivo, REG3A shRNA significantly inhibited primary TNBC cell xenograft growth. In REG3A-silenced xenograft tissues, reduced REG3A levels, Akt-mTOR inhibition, and activated apoptosis were evident. ZNF680-caused REG3A overexpression drives tumorigenesis in breast cancer possibly by stimulating Akt-mTOR activation, emerging as a promising and innovative cancer target.

Jin X ，Yang S ，Lu X ，Chen X ，Dai W ... -  《-》

Overexpressed Gαi1 exerts pro-tumorigenic activity in nasopharyngeal carcinoma.

Yin DP ，Zhang H ，Teng H ，Zhang D ，Chen P ，Xie L ，Liu JS ... -  《Cell Death & Disease》

Expression and functional implications of YME1L in nasopharyngeal carcinoma.

Mitochondria play a crucial role in the progression of nasopharyngeal carcinoma (NPC). YME1L, a member of the AAA ATPase family, is a key regulator of mitochondrial function and has been implicated in various cellular processes and diseases. This study investigates the expression and functional significance of YME1L in NPC. YME1L exhibits significant upregulation in NPC tissues from patients and across various primary human NPC cells, while its expression remains relatively low in adjacent normal tissues and primary nasal epithelial cells. Employing genetic silencing through the shRNA strategy or knockout (KO) via the CRISPR-sgRNA method, we demonstrated that YME1L depletion disrupted mitochondrial function, leading to mitochondrial depolarization, reactive oxygen species (ROS) generation, lipid peroxidation, and ATP reduction within primary NPC cells. Additionally, YME1L silencing or KO substantially impeded cell viability, proliferation, cell cycle progression, and migratory capabilities, concomitant with an augmentation of Caspase-apoptosis activation in primary NPC cells. Conversely, ectopic YME1L expression conferred pro-tumorigenic attributes, enhancing ATP production and bolstering NPC cell proliferation and migration. Moreover, our findings illuminate the pivotal role of YME1L in Akt-mTOR activation within NPC cells, with Akt-S6K phosphorylation exhibiting a significant decline upon YME1L depletion but enhancement upon YME1L overexpression. In YME1L-silenced primary NPC cells, the introduction of a constitutively-active Akt1 mutant (caAkt1, at S473D) restored Akt-S6K phosphorylation, effectively ameliorating the inhibitory effects imposed by YME1L shRNA. In vivo studies revealed that intratumoral administration of YME1L-shRNA-expressing adeno-associated virus (AAV) curtailed subcutaneous NPC xenograft growth in nude mice. Furthermore, YME1L downregulation, concurrent with mitochondrial dysfunction and ATP reduction, oxidative injury, Akt-mTOR inactivation, and apoptosis induction were evident within YME1L-silenced NPC xenograft tissues. Collectively, these findings shed light on the notable pro-tumorigenic role by overexpressed YME1L in NPC, with a plausible mechanism involving the promotion of Akt-mTOR activation.

Cheng F ，Huang H ，Yin S ，Liu JS ，Sun P ... -  《Cell Death & Disease》

Ononin inhibits triple-negative breast cancer lung metastasis by targeting the EGFR-mediated PI3K/Akt/mTOR pathway.

The spreading of cancer cells from the primary tumor site to other parts of the body, known as metastasis, is the leading cause of cancer recurrence and mortality in patients with triple-negative breast cancer (TNBC). Overexpression of epidermal growth factor receptor (EGFR) is observed in approximately 70% of TNBC patients. EGFR is crucial for promoting tumor metastasis and associated with poor prognosis. Therefore, it is vital to identify effective therapeutic strategies targeting EGFR inhibition. Ononin, an isoflavonoid found in various plants, such as clover and soybeans, has been shown to have anticancer properties in several cancers. In the present study, we aimed to investigate the effects of ononin on TNBC lung metastasis and the associated molecular pathways. We used various assays, including cell viability, colony formation, Transwell, wound healing, ELISA, Western blotting, and staining techniques, to achieve this objective. The results demonstrated that ononin effectively suppressed cellular proliferation and induced apoptosis, as evidenced by the cell viability assay, colony formation assay, and expression of apoptosis markers, and reduced the metastatic capabilities of TNBC cells. These effects were achieved through the direct suppression of cell adhesion, invasiveness and motility. Furthermore, in TNBC xenograft lung metastatic models, ononin treatment significantly reduced tumor growth and lung metastasis. Additionally, ononin reversed the epithelial-mesenchymal transition (EMT) by downregulating the expression of EMT markers and matrix metalloproteinases, as confirmed by Western blot analysis. Furthermore, ononin treatment reduced EGFR phosphorylation and suppressed the PI3K, Akt, and mTOR signaling pathways, which was further confirmed using EGFR agonists or inhibitors. Importantly, ononin treatment did not exert any toxic effects on liver or kidney function. In conclusion, our findings suggest that ononin is a safe and potentially therapeutic treatment for TNBC metastasis that targets the EGFR-mediated PI3K/Akt/mTOR pathway. Further studies are warranted to validate its efficacy and explore its potential clinical applications.

Ganesan K ，Xu C ，Wu J ，Du B ，Liu Q ，Sui Y ，Song C ，Zhang J ，Tang H ，Chen J ... -  《-》

Protective effect of hsa-miR-570-3p targeting CD274 on triple negative breast cancer by blocking PI3K/AKT/mTOR signaling pathway.

To find out the role of hsa-miR-570-3p targeting CD274 in triple negative breast cancer (TNBC) via PI3K/AKT/mTOR signaling pathway. Hsa-miR-570-3p and CD274 expressions in 175 TNBC patients were detected by qRT-PCR and immunohistochemistry respectively. The human TNBC cell lines (MDA-MB-468 and MDA-MB-231) were used to verify the targeting relationship between hsa-miR-570-3p and CD274 via dual-luciferase reporter gene assay. Then, MDA-MB-468 and MDA-MB-231 cells were divided into Blank, miR-NC, miR-570-3p mimics, NC siRNA, CD274 siRNA, and miR-570-3p inhibitors + CD274 siRNA groups. Next, the biological activities of cells were detected by MTT, Cell-Light EdU, Annexin-V-FITC/PI, wound healing and Transwell invasion assays. Western blotting was conducted to detect protein expressions.MiR-570-3p expression was lower in tumor tissues than that in adjacent normal tissues, which was more obvious in CD274-positive TNBC patients, which targeted CD274 in TNBC cell lines. MiR-570-3p inhibited cell proliferation, invasion and migration, but induced cell apoptosis accompanying the upregulation of apoptotic proteins and downregulation of anti-apoptotic protein. CD274 siRNA had the similar results of miR-570-3p mimics, which could be reversed by miR-570-3p inhibitors. Besides, both miR-570-3p mimics and CD274 siRNA blocked PI3K/AKT/mTOR signaling pathway in TNBC cell lines. Hsa-miR-570-3p was downregulated and CD274 was upregulated in TNBC patients. Besides, hsa-miR-570-3p targeted CD274 to inhibit cell proliferation, invasion, migration, and induce cell apoptosis, which may be related to the suppression of PI3K/AKT/mTOR pathway.

Wang LL ，Huang WW ，Huang J ，Huang RF ，Li NN ，Hong Y ，Chen ML ，Wu F ，Liu J ... -  《-》