ABSTRACT
Background: The role of disulfidptosis-related lncRNAs remains unclear in lung adenocarcinoma. Methods: Analysis in R software was conducted using different R packages, which are based on the public data from The Cancer Genome Atlas (TCGA) database. The transwell assay was used to evaluate the invasion and migration abilities of lung cancer cells. Results: In our study, we identified 1401 lncRNAs significantly correlated with disulfidptosis-related genes (|Cor| > 0.3 and P < 0.05). Then, we constructed a prognosis model consisting of 11 disulfidptosis-related lncRNAs, including AL133445.2, AL442125.1, AC091132.2, AC090948.1, AC020765.2, CASC8, AL606834.1, LINC00707, OGFRP1, U91328.1, and GASAL1. This prognosis model has satisfactory prediction performance. Also, the risk score and clinical information were combined to develop a nomogram. Analyses of biological enrichment and immune-related data were used to identify underlying differences between patients at high-risk and low-risk groups. Moreover, we noticed that the immunotherapy nonresponders have higher risk scores. Meanwhile, patients at a high risk responded more strongly to docetaxel, paclitaxel, and vinblastine. Furthermore, further analysis of the model lncRNA OGFRP1 was conducted, including clinical, immune infiltration, biological enrichment analysis, and a transwell assay. We discovered that by inhibiting OGFRP1, the invasion and migration abilities of lung cancer cells could be remarkably hindered. Conclusion: The results of our study can provide directions for future research in the relevant areas. Moreover, the prognosis signature we identified has the potential for clinical application.
Subject(s)
Adenocarcinoma , Lung Neoplasms , RNA, Long Noncoding , Humans , RNA, Long Noncoding/genetics , Prognosis , Nomograms , Lung Neoplasms/genetics , Adenocarcinoma/genetics , Tumor Microenvironment/geneticsABSTRACT
Tetratricopeptide repeat domain 9A (TTC9A) belongs to a family of TTC9 proteins. Its induction by progesterone in breast cancer cells was associated with marked growth inhibition and induction of focal adhesion. TTC9A interacts specifically with actin-binding protein tropomyosin Tm5NM-1 which stabilizes actin filament and focal adhesion. However, the function of TTC9A is still obscure. This study exploited mice model to characterize the regulation of TTC9A gene expression during mammary development and explored possible mechanisms of TTC9A gene regulation. It was demonstrated that mammary TTC9A expression is distinctively down-regulated in gland undergoing functional differentiation (lactation) and up-regulated during involution. Furthermore, TTC9A expression during lactation and involution is regulated by the factors in the local microenvironment. This is illustrated with teat sealing model in which the teat sealed glands (undergoing involution) expressed significantly higher levels of TTC9A protein and mRNA than the contralateral non-sealed lactating glands. Importantly, this local induction of TTC9A expression upon involution coincided with the re-activation of estrogen receptor α (ERα). Together with the observation that TTC9A is a direct ERα target gene, we propose that the fall and rise of TTC9A levels during lactation and involution is caused by the changes of ERα activity that is in turn regulated by the factors in the microenvironment.
Subject(s)
Cellular Microenvironment , Estrogen Receptor alpha/metabolism , Gene Expression Regulation, Developmental , Lactation/physiology , Mammary Glands, Animal/growth & development , Microfilament Proteins/genetics , Animals , Female , Humans , Lactation/genetics , Mice , Mice, Inbred BALB CABSTRACT
BACKGROUND: Tetratricopeptide repeat domain 9A (TTC9A) protein is a recently identified protein which contains three tetratricopeptide repeats (TPRs) on its C-terminus. In our previous studies, we have shown that TTC9A was a hormonally-regulated gene in breast cancer cells. In this study, we found that TTC9A was over-expressed in breast cancer tissues compared with the adjacent controls (P < 0.00001), suggesting it might be involved in the breast cancer development process. The aim of the current study was to further elucidate the function of TTC9A. METHODS: Breast samples from 25 patients including the malignant breast tissues and the adjacent normal tissues were processed for Southern blot analysis. Yeast-two-hybrid assay, GST pull-down assay and co-immunoprecipitation were used to identify and verify the interaction between TTC9A and other proteins. RESULTS: Tropomyosin Tm5NM-1 was identified as one of the TTC9A partner proteins. The interaction between TTC9A and Tm5NM-1 was further confirmed by GST pull-down assay and co-immunoprecipitation in mammalian cells. TTC9A domains required for the interaction were also characterized in this study. The results suggested that the first TPR domain and the linker fragment between the first two TPR domains of TTC9A were important for the interaction with Tm5NM-1 and the second and the third TPR might play an inhibitory role. CONCLUSION: Since the primary function of tropomyosin is to stabilize actin filament, its interaction with TTC9A may play a role in cell shape and motility. In our previous results, we have found that progesterone-induced TTC9A expression was associated with increased cell motility and cell spreading. We speculate that TTC9A acts as a chaperone protein to facilitate the function of tropomyosins in stabilizing microfilament and it may play a role in cancer cell invasion and metastasis.
Subject(s)
Breast Neoplasms/metabolism , Nerve Tissue Proteins/physiology , Tropomyosin/chemistry , Tropomyosin/physiology , Animals , Breast Neoplasms/pathology , COS Cells , Chlorocebus aethiops , Gene Expression Regulation, Neoplastic , Humans , Neoplasm Invasiveness , Neoplasm Metastasis , Nerve Tissue Proteins/metabolism , Peptides/chemistry , Progesterone/metabolism , Protein Structure, Tertiary , Tropomyosin/metabolism , Two-Hybrid System TechniquesABSTRACT
Tetratricopeptide repeat domain 9 (TTC9) mRNA was drastically up-regulated by progesterone in progesterone receptor-transfected breast cancer cells MDA-MB-231. This up-regulation is coupled with progesterone-mediated growth inhibition and induction of focal adhesion. We have generated mouse polyclonal antibody against a predicted 222 aa TTC9 protein and identified a 25 kDa TTC9 protein that is widely expressed in human tissues, with the highest expression in the brain. Immunostaining and cell fractionation studies revealed that TTC9 is predominantly localized to the endoplasmic reticulum. The level of TTC9 protein in MCF-7 cells is regulated by various factors and chemical reagents including estrogen, progesterone, growth factors, ICI182,780, and p38 kinase inhibitor SB203580. Growth factor-induced TTC9 protein expression was inhibited by estrogen and abolished by ERK inhibitor PD98059. Though the function of TTC9 is not yet clear, the susceptibility of its protein level to biological and chemical agents suggests that TTC9 is a biologically significant protein.
