Project description:Background: Estrogen receptor-positive (ER+) breast cancers represent approximately two-thirds of all breast cancers and have a sustained risk of late disease recurrence. Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors have shown significant efficacy in ER+ breast cancer. However, their effects are still limited by drug resistance. In this study, we aim to explore the role of long noncoding RNA TROJAN in ER+ breast cancer. Methods: The expression level of TROJAN in breast cancer tissue and cell lines was determined by quantitative real-time PCR. In vitro and in vivo assays as well as patient derived organoids were preformed to explore the phenotype of TROJAN in ER+ breast cancer. The TROJAN-NKRF-CDK2 axis were screened and validated by RNA pull-down, mass spectrometry, RNA immunoprecipitation, microarray, dual-luciferase reporter and chromatin immunoprecipitation assays. Results: Herein, we showed that TROJAN was highly expressed in ER+ breast cancer. TROJAN promoted cell proliferation and resistance to a CDK4/6 inhibitor and was associated with poor survival in ER+ breast cancer. TROJAN can bind to NKRF and inhibit its interaction with RELA, upregulating the expression of CDK2. The inhibition of TROJAN abolished the activity of CDK2, reversing the resistance to CDK4/6 inhibitor. A TROJAN antisense oligonucleotide sensitized breast cancer cells and organoids to the CDK4/6 inhibitor palbociclib both in vitro and in vivo. Conclusions: TROJAN promotes ER+ breast cancer proliferation and is a potential target for reversing CDK4/6 inhibitor resistance.
Project description:Breast cancer subtype-specific lncRNAs AL078604.2 and LINC01269 were knockdown in breast cancer cell lines LncRNA AL078604.2 was knockdown by an anti-AL076804.2 antisense oligonucleotides (ASOs) in triple-negative breast cancer cell lines MDA-MB-231 and MDA-MB-468 breast cancer cells. LncRNA LINC01269 was knockdown by an anti-LINC01269 ASOs in HER2+ SKBR3 breast cancer cells. To ensure the initial presence of AL078604.2 and LINC01269 in their respective cell lines, qPCR analysis was performed to confirm their expression levels prior to knockdown experiments. The effectiveness of knockdown was confirmed by qPCR analysis, which validated the reduction in AL078604.2 and LNC01269 expression in their corresponding cell lines following ASO treatment.
Project description:LncRNA LINC01929 was knocked down using anti-LINC01929 antisense oligonucleotides (ASOs) in the ER+ breast cancer cell line MCF7 and the triple-negative breast cancer cell line MDA-MB-231.
Project description:Cryptococcal meningitis (CM) is a fatal compliation. Macrophages work as Trojan horses transferring Cryptococcus neoformans (C. neoformans) into the brain. Mechanisms for C. neoformans Trojan horses are largely elusive. In this study, we performed scRNA-Seq on immune cells infiltrated into the brain in a murine model of CM. Bioinformatics analysis reveals that phosphodiesterase 4B (PDE4B) ranks top in regulating macrophage Trojan horses. Melanin, a virulence factor for Cn, decreased PDE4B in macrophages. PDE4B inhibitor promoted the Cn Trojan horse across the blood-brain-barrier (BBB) in vitro and in vivo. As similar, PDE4B knockout increased fungi burden in the brain, which is, at least partially, rescued by macrophages depletion. In contrast, PDE4B activation diminished C. neoformans brain infection. Mechanistically, PDE4B inhibition increased CXCR4 and CCR7 on C. neoformans macrophage Trojan horses, a process regulated by the cAMP/PKA signaling pathway. Dexamethasone, commonly used to treat Pneumocystis infections in AIDS patients, significantly decreased PDE4B expression in macrophages. Overall, this study reveals that PDE4B plays a crucial role in C. neoformans macrophage Trojan horses and serves as a potential therapeutic target for CM.