Exosomal miR-122-3p represses the growth and metastasis of MCF-7/ADR cells by targeting GRK4-mediated activation of the Wnt/β-catenin pathway

Breast cancer (BC) is a common cancer whose incidence continues to grow while its medical progress has stagnated. miRNAs are vital messengers that facilitate communications among different cancer cells. This study was to reveal the correlation of miR-122-3p expression with BC metastasis and Adriamycin (ADM) resistance and its mechanism of inhibiting BC metastasis. We found that expression of miR-122-3p is negatively correlated with BC metastasis and is lower in MCF-7/ADR cells. Overexpression of miR-122-3p in MCF-7/ADR cancer cells impairs their ability to migrate, invade, and stimulate blood vessel formation. Further research found that miR-122-3p directly binds to the 3' UTR of GRK4, reducing the phosphorylation of LRP6, which activates the Wnt/β-catenin signaling pathway, facilitating BC development and metastasis. In addition, we observed that miR-122-3p is present in MCF-7  cells, and treatment of MCF-7/ADR cells with MCF-7-derived exosomes, but not with exosomes from miR-122-3p-deficient MCF-7 cells, has identical effects to miR-122-3p overexpression. Data from xenograft experiments further suggest that excess miR-122-3p and MCF-7-derived exosomes inhibit the growth and metastasis of MCF-7/ADR cancer cells in vivo. In conclusion our data reveal that exosomal miR-122-3p may negatively regulate BC growth and metastasis, potentially serving as a diagnostic and druggable target for BC treatment.

miR-122-3p targets UBE2I to regulate the immunosuppression of liver cancer and the intervention of Liujunzi formula

ETHNOPHARMACOLOGICAL RELEVANCE

Liujunzi formula has been used to treat liver cancer in China for many years, but its underlying mechanism remains unclear. We previously found that decreased expression of miR-122-3p was associated with liver cancer. In this study, we aimed to explore the target of miR-122-3p and the effect of the Liujunzi formula on miR-122-3p and its downstream events in liver cancer.

MATERIAL AND METHODS

Bioinformatics pinpointed potential targets of miR-122-3p. The actual target was confirmed by miRNA mimic/inhibitor transfections and a dual-luciferase reporter assay. RNA-seq looked at downstream genes impacted by this target. Flow cytometry checked for changes in T cell apoptosis levels after exposing them to liver cancer cells. Gene expression was measured by RT-qPCR, western blotting, and immunofluorescence staining.

RESULTS

Cell experiments found the Liujunzi extract (LJZ) upregulated miR-122-3p and in a dose-dependent manner. Bioinformatics analysis found UBE2I was a potential target of miR-122-3p, which was validated through experiments using miRNA mimics/inhibitors and a dual-luciferase reporter assay. RNA-seq data implicated the NF-κB pathway as being downstream of the miR-122-3p/UBE2I axis, further confirmed by forcing overexpression of UBE2I. Bioinformatic evidence suggested a link between UBE2I and T cell infiltration in liver cancer. Given that the NF-κB pathway drives PD-L1 expression, which can inhibit T cell infiltration, we investigated whether PD-L1 is a downstream effector of miR-122-3p/UBE2I. This was corroborated through mining public databases, UBE2I overexpression studies, and tumor-T cell co-culture assays. In addition, we also confirmed that LJZ downregulates UBE2I and NF-κB/PD-L1 pathways through miR-122-3p. LJZ also suppressed SUMOylation in liver cancer cells and protected PD-1+ T cells from apoptosis induced by co-culture with tumor cells. Strikingly, a miR-122-3p inhibitor abrogated LJZ's effects on UBE2I and PD-L1, and UBE2I overexpression rescued the LJZ-mediated effects on NF-κB and PD-L1.

CONCLUSIONS

miR-122-3p targets UBE2I, thereby suppressing the NF-κB signaling cascade and downregulating PD-L1 expression, which potentiates anti-tumor immune responses. LJZ bolsters anti-tumor immunity by modulating the miR-122-3p/UBE2I/NF-κB/PD-L1 axis in liver cancer cells.

miR-122-3p Alleviates LPS-Induced Pyroptosis of Macrophages via Targeting NLRP1

OBJECTIVE

Sepsis, a life-threatening organ dysfunction, is among the leading causes of mortality in intensive care units. Sepsis occurrence is associated with macrophage pyroptosis, and microRNAs (miRNAs) have emerged as key factors in this process. However, the specific role of miR-122-3p in pyroptosis during sepsis progression and its underlying mechanisms remain to be fully elucidated.

METHODS

We established an in vitro sepsis model using lipopolysaccharide (LPS)-activated macrophages, followed by transfection of a miR-122-3p mimic into RAW264.7 macrophages. We subsequently determined the effects of miR-122-3p on cell viability and pyroptosis using cell viability, western blot, and qPCR assays. The binding affinity between miR-122-3p and NLR pyrin domain containing 1 (NLRP1) mRNA was then confirmed using a dual-luciferase reporter assay. Finally, the secretion of pro-inflammatory cytokines (interleukin (IL)-2, IL-6, and tumor necrosis factor-α (TNF-α) was determined using ELISA.

RESULTS

The results revealed that LPS treatment lead to a significant increase in the production of pro-inflammatory cytokines including IL-2, IL-6, and TNF-α in RAW264.7 cells. We observed that overexpression of miR-122-3p effectively restored cell viability and attenuated the expression of key inflammatory markers promoted by LPS, such as caspase-1, pro-caspase-1, IL-18, IL-1β, NLRP3, apoptosis-associated speck-like protein containing CARD, and cleaved- gasdermin-D. Our data indicate that miR-122-3p is capable of directly bounding to NLRP1 and inhibiting its expression.

CONCLUSIONS

These results confirmed that miR-122-3p plays a crucial role in the inhibition of sepsis by suppressing macrophage pyroptosis in an NLRP1-dependent manner. Therefore, miR-122-3p presents as a promising therapeutic target for sepsis.