Diet restriction enhances the effect of immune checkpoint block by inhibiting the intratumoral mTORC1/B7-H3 axis.

Immune checkpoint blockade therapy has demonstrated significant therapeutic efficacy in certain cancer types; however, the impact of dietary restriction remains scarcely reported in this context. This study aimed to investigate the influence of dietary restriction on anti-PDL-1 therapy and the interplay of immune cells within this context. Using an anti-PDL-1 regimen combined with dietary restrictions, tumor progression was assessed in LLC-bearing mice. Flow cytometry was employed to analyze immune cell infiltration and differentiation levels within the tumor microenvironment. The expression of mTORC1/B7-H3 in tumors subjected to dietary restriction was also examined. LLC tumors with elevated B7-H3 expression were validated in mice to determine its inhibitory effect on immune cell proliferation and differentiation. A CD3/B7-H3 chimeric antibody was developed for therapeutic intervention in B7-H3 overexpressing tumors, with subsequent T cell responses assessed through flow cytometry. Dietary restriction potentiated the effect of anti-PDL1 therapy by suppressing the intratumorally mTORC1/B7-H3 axis. In vivo experiments demonstrated that elevated B7-H3 expression in tumors reduced infiltration and activation of CD8 + T cells within the tumor, while it did not affect tumor-infiltrating Tregs. In vitro studies revealed that high B7-H3 expression influenced the proliferation and activation of CD8 + T cells within a Coculture system. The constructed CD3/B7-H3 chimeric antibody prominently activated TCR within B7-H3 overexpressing tumors and impeded tumor progression. The findings suggest that dietary restriction enhances the efficacy of immune checkpoint blockade by modulating the intratumoral mTORC1/B7-H3 axis.

Targeting PAK4 reverses cisplatin resistance in NSCLC by modulating ER stress.

Chemoresistance poses a significant impediment to effective treatments for non-small-cell lung cancer (NSCLC). P21-activated kinase 4 (PAK4) has been implicated in NSCLC progression by invasion and migration. However, the involvement of PAK4 in cisplatin resistance is not clear. Here, we presented a comprehensive investigation into the involvement of PAK4 in cisplatin resistance within NSCLC. Our study revealed enhanced PAK4 expression in both cisplatin-resistant NSCLC tumors and cell lines. Notably, PAK4 silencing led to a remarkable enhancement in the chemosensitivity of cisplatin-resistant NSCLC cells. Cisplatin evoked endoplasmic reticulum stress in NSCLC. Furthermore, inhibition of PAK4 demonstrated the potential to sensitize resistant tumor cells through modulating endoplasmic reticulum stress. Mechanistically, we unveiled that the suppression of the MEK1-GRP78 signaling pathway results in the sensitization of NSCLC cells to cisplatin after PAK4 knockdown. Our findings establish PAK4 as a promising therapeutic target for addressing chemoresistance in NSCLC, potentially opening new avenues for enhancing treatment efficacy and patient outcomes.

Corrigendum: The m6A-methylated mRNA pattern and the activation of the Wnt signaling pathway under the hyper-m6A-modifying condition in the keloid.

[This corrects the article DOI: 10.3389/fcell.2022.947337.].

The m6A-methylated mRNA pattern and the activation of the Wnt signaling pathway under the hyper-m6A-modifying condition in the keloid.

Purpose: The present study was carried out to investigate the global m6A-modified RNA pattern and possible mechanisms underlying the pathogenesis of keloid. Method: In total, 14 normal skin and 14 keloid tissue samples were first collected on clinics. Then, three samples from each group were randomly selected to be verified with the Western blotting to determine the level of methyltransferase and demethylase. The total RNA of all samples in each group was isolated and subjected to the analysis of MeRIP sequencing and RNA sequencing. Using software of MeTDiff and htseq-count, the m6A peaks and differentially expressed genes (DEGs) were determined within the fold change >2 and p-value < 0.05. The top 10 pathways of m6A-modified genes in each group and the differentially expressed genes were enriched by the Kyoto Encyclopedia of Genes and Genomes signaling pathways. Finally, the closely associated pathway was determined using the Western blotting and immunofluorescence staining. Results: There was a higher protein level of WTAP and Mettl3 in the keloid than in the normal tissue. In the keloid samples, 21,020 unique m6A peaks with 6,573 unique m6A-associated genetic transcripts appeared. In the normal tissue, 4,028 unique m6A peaks with 779 m6A-associated modified genes appeared. In the RNA sequencing, there were 847 genes significantly changed between these groups, transcriptionally. The genes with m6A-methylated modification and the upregulated differentially expressed genes between two tissues were both mainly related to the Wnt signaling pathway. Moreover, the hyper-m6A-modified Wnt/ß-catenin pathway in keloid was verified with Western blotting. From the immunofluorescence staining results, we found that the accumulated fibroblasts were under a hyper-m6A condition in the keloid, and the Wnt/ß-Catenin signaling pathway was mainly activated in the fibroblasts. Conclusion: The fibroblasts in the keloid were under a cellular hyper-m6A-methylated condition, and the hyper-m6A-modified highly expressed Wnt/ß-catenin pathway in the dermal fibroblasts might promote the pathogenesis of keloid.

miR-203a-3p-DNMT3B feedback loop facilitates non-small cell lung cancer progression.

It has been reported that microRNA-203a-3p (miR-203a-3p) modulates cell proliferation, migration and invasion in a variety of cancer cell types. However, little is known about its role in lung cancer progression. The present study found that miR-203a-3p was downregulated in non-small cell lung cancer (NSCLC) cell lines and tissues. Overexpression of miR-203a-3p inhibits NSCLC cell proliferation, migration and invasion, and promotes cellular apoptosis in vitro. Restoration of miR-203a-3p expression in A549 and NCI-H520 cells enhances their chemosensitivity. Further experiments showed that DNA methyltransferase 3B (DNMT3B) was a direct target of miR-203a-3p. In addition, the present results revealed that promoter hypermethylation was the potential mechanism responsible for low miR-203a-3p expression in NSCLC. Notably, feedback regulation between miR-203a-3p and DNMT3B was observed in NSCLC. Moreover, Overexpression of miR-203a-3p reduces tumor growth in vivo. In summary, the present study has identified an miR-203a-3p-DNMT3B feedback loop that facilitates NSCLC progression.