The Function And Transcriptional Regulation Of Transcriptional Regulator PRDM1 In Lung Cancer

Background:Lung cancer is one of the highest incidence and mortality in all kinds of cancer in the worldwide.Common treatments include surgery,chemotherapy,and radiotherapy,while less than 20% of people diagnosed with lung cancer survive five years after the diagnosis.Tumor metastasis is the leading cause of death among lung cancer patients.Therefore,we target lung cancer as our research objective to explore the molecular mechanism for abnormal expression of transcription factor in tumor metastasis.Our lab mainly carries out scientific research on tumorigenesis and metastasis of lung cancer and published the paper ―Aiolos Promotes Anchorage Independence by Silencing p66 Shc Transcription in Cancer Cells‖ in Cancer Cell 2014 May.Moreover,we obtained PRDM1 downregulated by Aiolos using the microarray platform.The zinc-finger transcriptional repressor,PRDM1(also known as Blimp1),originally identified as a silencer of β-interferon gene expression and a master regulator controlling terminal differentiation of B lymphocytes,also governs T-lymphocyte homeostasis,primordial germ cell specification,epidermal terminal differentiation and stem cell maintenance in the sebaceous gland.So far,many reports show that PRDM1 gene alterations and abnormal expression are related to malignant lymphoma and leukemia.PRDM1 also aberrantly expressed in some solid tumors.Decreased PRDM1 expression correlates with increased pathological grade and poor survival of human gliomas.Increased PRDM1 expression suppressed breast cell migration.Therefore,the role of PRDM1 in solid tumors: oncogene or tumor suppressor gene? Objective:By observing of cell biological behavior,we hope to clarify the PRDM1 function in lung cancer cells.By detecting the changes of m RNA and protein,we explore the the molecular mechanism of cell behavior changes.Via tail vein injection in nude mice assay,we determine the correlation between PRDM1 knockdown and tumor cell metastasis.By analysing microarray and RNA-sequencing data,and detecting the m RNA levels in many cells lines,we confirm the negative correlation between PRDM1 and Aiolos.By researching the interaction between Aiolos/IKZF3 and PRDM1 gene,we pinpoint the mechanism of transcriptional downregulation of PRDM1 expression in lung cancer cells.To sum up,we hopefully gain significant insight into the mechanism with tumorigenesis and metastasis in lung cancer and discover new therapeutic targets for molecular therapy.Methods and results:1.By analysing Aiolos overexpression microarray data,PRDM1 was chose as our target gene.2.By analysing the microarray of 206 human lung epithelial cell lines including 59 bronchial epithelium cell lines and 147 lung cancer cell lines,the correlation between PRDM1 abnormal expression and tumorigenesis and metastasis in lung cancer.3.By using Lenti-virus gene transport system,we knockdown PRDM1 expression degree in A549 cells,observed cells behavior change,and found the obility of invasion,adherin and anoikis resistance were enhanced.4.By using Lenti-virus gene transport system,we knockdown PRDM1 expression degree in A549 cells,and found the Fibronectin level of m RNA and protein were increased with real-time PCR and western blot.5.By using Lenti-virus gene transport system,we knockdown PRDM1 in A549 cell line,seeded cell to nude mice by tail vein injection,then kept the mice until they died of lung cancer,recorded the death time and.The result shows survival time of experimental group is shorter than control group and both groups detected metastasis in lung.The reason may be that PRDM1 participates in the progress of cancer cells shedding,passing the basement membrane and entering the blood,while the tail vein injection experiment imitates the progress in blood.6.By analysing RNA-sequencing and running RT-PCR detection in multiple cell lines,we made sure that the negative correlation between PRDM1 and Aiolos.By running RT-PCR detection of overexpression Aiolos,we confirmed Aiolos downregulates PRDM1 expression.7.By using chromatin-IP technology and luciferase reporter assay,we revealed that Aiolos can bind to the promoter region of PRDM1 to inhibit its expression.Conclusion: 1.Knockdown PRDM1 expression in lung cancer cells can enhance cell ability of invasion,anoikis resistance and isolation from tumor in situ.2.Survival time of experimental group is shorter than control group in tail vein injection assay.3.Transcription factor Aiolos can bind to the promoter region of PRDM1 gene and inhibit PRDM1 expression in lung cancer.