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.

The number of coronavirus disease 2019 (COVID-19) cases has exceeded 10 million. However, little is known about the epidemiology and clinical characteristics of COVID-19 infants. We collected medical information of 46 confirmed patients (<1 year old) and retrospectively analyzed epidemiological history, clinical symptoms, and laboratory test results. The median age was 5 (interquartile range, 2–7) months. Sixteen cases had fever and 27 cases had cough. Moderate disease was present in 40 cases and cardiac injury occurred in 38 cases, following by liver dysfunction in 20 cases and lymphopenia in no cases. Of all infant patients, 2 received invasive mechanical ventilation and 1 died with multiple organ dysfunction syndrome.

Background: DNA damage and DNA damage repair (DDR) are important therapeutic targets for triple-negative breast cancer (TNBC), a subtype with limited chemotherapy efficiency and poor outcome. However, the role of microRNAs in the therapy is emerging. In this study, we explored whether miR-26a-5p could act as BRCAness and enhance chemotherapy sensitivity in TNBC.Methods: Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used to detect the expression of miR-26a-5p in breast cancer tissues and cell lines. CCK-8 was used to measure drug sensitivity in concentration gradient and time gradient. Comet assay was used to detect DNA damage. Flow cytometry was performed to examine apoptosis. Moreover, we used western blot and immunofluorescence to detect biomarkers. Luciferase reporter assay was performed to verify the combination of miR-26a-5p and 3’UTR of target gene. Hormone deprivation and stimulation assay were used to validate the effect of hormone receptors on the expression of miR-26a-5p. Chromatin immunoprecipitation (ChIP) assays were used to verify the binding sites of ER-a or PR with the promoter of miR-26a-5p. Animal experiments were performed to the effect of miR-26a-5p on Cisplatin treatment.Results: The expression of miR-26a-5p was significantly downregulated in TNBC. Overexpressing miR-26a-5p enhanced the Cisplatin-induced DNA damage and following apoptosis. Interestingly, miR-26a-5p promoted the expression of Fas without Cisplatin stimulating. It suggested that miR-26a-5p provided a hypersensitivity state of death receptor apoptosis and promoted the Cisplatin sensitivity of TNBC cells in vitro and in vivo. Besides, miR-26a-5p negatively regulated the expression of BARD1 and NABP1 and resulted in homologous recombination repair defect (HRD). Notably, overexpressing miR-26a-5p not only facilitated the Olaparib sensitivity of TNBC cells but also the combination of Cisplatin and Olaparib. Furthermore, hormone receptors functioned as transcription factors in the expression of miR-26a-5p, which explained the reasons that miR-26a-5p expressed lowest in TNBC.Conclusions: Taken together, we reveal the important role of miR-26a-5p in Cisplatin sensitivity and highlight its new mechanism in DNA damage and synthetic lethal.

Long non-coding RNAs (lncRNAs) have been shown to drive cancer progression. However, the function of lncRNAs and the underlying mechanism in early-stage breast cancer(BC) have rarely been investigated. Datasets of pre-invasive ductal carcinoma in situ (DCIS), invasive ductal BC (IDC) and normal breast tissue from TCGA and GEO databases were used to conduct bioinformatics analysis. LncRNA CARMN was identified as a tumor suppressor in early-stage BC and related to a better prognosis. CARMN over-expression inhibited MMP2 mediated migration and EMT in BC. Further analysis showed that CARMN was located in the nucleus and functioned as an enhancer RNA (eRNA) in mammary epithelial cell. Mechanically, CARMN binding protein DHX9 was identified by RNA pull-down and mass spectrometry (MS) assays and it also bound to the MMP2 promoter to activate its transcription. As a decoy, CARMN competitively bound to DHX9 and blocked MMP2 transcriptional activation, thereby inhibiting metastasis and EMT of BC cells. These findings reveal the important role of CARMN as a tumor suppressor in the metastasis and a potential biomarker for progression in early-stage BC.

Background: Since the outbreak of coronavirus disease 2019 in December 2019, more than 8 million cases have occurred worldwide as of June 16, 2020. However, it is important to distinguish COVID-19 from other respiratory infectious diseases, such as influenza. Here, we comparatively described the clinical characteristics of children with COVID-19 and paediatric patients with influenza. Methods: In this retrospective, single-centre study, we reviewed the electronic medical records of 585 paediatric patients with COVID-19 or influenza in Wuhan Children’s Hospital, China. Clinical and epidemiological characteristics, laboratory findings, and clinical outcomes were comparatively analysed. Results: The median ages were 6.96 years (IQR, 2–10.81) for children with confirmed COVID-19, 2.67 years (IQR, 1.03–15.25) for those with influenza A and 3.67 years (IQR, 1.62–5.54) for those with influenza B. Fever was a symptom in 84 (34.7%) COVID-19 cases, 132 (70.21%) influenza A cases and 111 (74.50%) influenza B cases. The median length of stay (LOS) was 11 (8–15) days for paediatric COVID-19 patients, 4 (3–6) days for influenza A patients and 5 (3–6) days for influenza B patients. Twenty-six (13.98%) influenza A patients and 18 (12.59%) influenza B patients presented with decreased white blood cell counts, while 13 (5.33%) COVID-19 patients presented with decreased white blood cell counts. Eight (3.28%) COVID-19 patients, 23 (12.71%) influenza A patients and 21 (14.79%) influenza B patients experienced lymphocytopenia. Acute cardiac injury occurred in 18 (7.29%) COVID-19 patients, while 37 (19.68%) influenza A and 27 (18.12%) influenza B patients had acute cardiac injury. Conclusion: In this study, the illnesses of children with COVID-19 were demonstrated to be less severe than those of paediatric patients with influenza, and COVID-19 patients had milder illness and fewer complications.