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Background: Targeted therapy for triple‐negative breast cancer (TNBC) remains a challenge. N6‐methyladenosine (m6A) is the most abundant internal mRNA modification in eukaryotes, and it regulates the homeostasis and function of modified RNA transcripts in cancer. However, the role of leucine‐rich pentatricopeptide repeat containing protein (LRPPRC) as an m6A reader in TNBC remains poorly understood. Methods: Western blotting, reverse transcription‐polymerase chain reaction (RT‐qPCR) and immunohistochemistry were used to investigate LRPPRC expression levels. Dot blotting and colorimetric enzyme linked immunosorbent assay (ELISA) were employed to detect m6A levels. In vitro functional assays and in vivo xenograft mouse model were utilised to examine the role of LRPPRC in TNBC progression. Liquid chromatography–mass spectrometry/mass spectrometry and Seahorse assays were conducted to verify the effect of LRPPRC on glycolysis. MeRIP‐sequencing, RNA‐sequencing, MeRIP assays, RNA immunoprecipitation assays, RNA pull‐down assays and RNA stability assays were used to identify the target genes of LRPPRC. Patient‐derived xenografts and organoids were employed to substantiate the synthetic lethality induced by LRPPRC knockdown plus glutaminase inhibition. Results: The expressions of LRPPRC and m6A RNA were elevated in TNBC, and the m6A modification site could be recognised by LRPPRC. LRPPRC promoted the proliferation, metastasis and glycolysis of TNBC cells both in vivo and in vitro. We identified lactate dehydrogenase A (LDHA) as a novel direct target of LRPPRC, which recognised the m6A site of LDHA mRNA and enhanced the stability of LDHA mRNA to promote glycolysis. Furthermore, while LRPPRC knockdown reduced glycolysis, glutaminolysis was enhanced. Moreover, the effect of LRPPRC on WD40 repeat domain‐containing protein 76 (WDR76) mRNA stability was impaired in an m6A‐dependent manner. Then, LRPPRC knockdown plus a glutaminase inhibition led to synthetic lethality. Conclusions: Our study demonstrated that LRPPRC promoted TNBC progression by regulating metabolic reprogramming via m6A modification. These characteristics shed light on the novel combination targeted therapy strategies to combat TNBC. [ABSTRACT FROM AUTHOR]

Osimertinib, a third-generation inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase, exhibits remarkable efficacy in prolonging the survival of patients with non-small cell lung cancer (NSCLC) carrying EGFR mutations, surpassing the efficacy of first- and second-generation EGFR tyrosine kinases. Nevertheless, the emergence of osimertinib resistance is inevitable, necessitating an investigation into the underlying mechanisms. Increasing evidence has revealed that non-coding RNAs (ncRNAs), including microRNAs, long ncRNAs, and circular RNAs, play a significant role in the development and progression of lung cancer. These ncRNAs regulate essential signaling pathways, offering a novel avenue for understanding the fundamental mechanisms of osimertinib resistance. Recent studies have reported the significant impact of ncRNAs on osimertinib resistance, achieved through various mechanisms that modulate treatment sensitivity. We provide a concise overview of the functions and underlying mechanisms of extensively researched ncRNAs in the development of osimertinib resistance and emphasize their potential clinical application in EGFR -mutated NSCLC resistant to osimertinib. Finally, we discuss the obstacles that must be addressed to effectively translate ncRNA-based approaches into clinical practice., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Zeng, Gan, Yu, Hu, Deng, Yin and Gao.)

Cancer-associated fibroblasts (CAFs) are prevalent in the tumor microenvironment of breast cancer, comprising a group of cell subpopulations with spatial, phenotypic, and functional heterogeneity. Due to the lack of specific markers for CAF subpopulations, their specific mechanisms in breast cancer remain unclear. We identified eight distinct CAF phenotypes in breast cancer using multiple single-cell RNA sequencing datasets and determined distinct transcription factors (TFs) of CAFs through SCENIC analysis. Our study highlights one CAF subtype in breast cancer, FN1+CAF2, associated with metastasis and macrophage polarization. We observed elevated FN1 expression in the stromal tissue of breast cancer patients. Furthermore, FN1 knockdown in CAFs reduced the migration ability of breast cancer cells. We identified a regulatory gene, MXRA5, in CAF2, which may play crucial roles in breast cancer. Our results indicated upregulated MXRA5 expression in breast cancer tissues and CAFs from patients with lymph node metastasis in the following experiment. Overall, our study reveals that the FN1+CAF2 subtype is associated with metastasis and suggests that MXRA5 may be a novel marker mediating the effects of CAF2 on breast cancer metastasis. This study enriches our understanding of CAF heterogeneity and offers new insights for treating breast cancer metastasis., Competing Interests: None., (AJCR Copyright © 2024.)

Simultaneous profiling of protein phosphorylation and glycosylation is very important to elucidate the bio-functions of these proteins. However, simultaneous enrichment of glyco- and phosphopeptides is the bottleneck in proteomics because of the low abundance of these species and ion suppression from non-modified peptides in mass spectrometry (MS). In this study, Fe 3+ immobilized hydrophilic interaction chromatography (HILIC) materials (termed polySD-SiO 2 , recently reported in our lab) and polySD-SiO 2 in the HILIC mode were employed for the simultaneous enrichment and subsequent separation of glyco- and phosphopeptides. The Fe 3+ immobilized polySD-SiO 2 could selectively enrich glycopeptides and phosphopeptides and the co-enriched peptides were further fractionated with polySD-SiO 2 in the HILIC mode. With the established method, glyco- and phosphopeptides were well enriched and divided into two fractions even from tryptic digests of a-casein, fetuin and BSA at a molar ratio of 1 : 2 : 400. Application of the established method to HeLa cell lysate resulted in a total of 1903 phosphopeptides and 141 glycosylation sites. These results demonstrate that the established method could selectively and simultaneously enrich and fractionate glyco- and phosphopeptides from complex peptide mixtures., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)