Pathogenesis Analysis Of Pituitary Adenoma Based On Gene Expression Profiling&changes Of B10 Cells In Pituitary Adenoma Tissues After Radiation Therapy

Pituitary gland,as an important endocrine organ,performs vital roles in organismal modulation through secreting several important hormones such as prolactin(PRL),growth hormone(GH),adrenocorticotropic hormone(ACTH),thyroid stimulating hormone(TSH).By regulating target glands hormone secretion,anterior pituitary participates in the development and normalization of tissues.Abnormality of pituitary tends to severely disrupt the body’s metabolic homeostasis,damaging various organs to different extents.Pituitary adenoma is a special intracranial tumor growing in the anterior pituitary which not just meets the characteristics of the tumor but also exhibits endocrine disorder.Pituitary adenoma accounts for about 10～20%of brain tumors,with a monoclonal antibody of origin.The incidence rate in intracranial tumors has been close to in the back row of meningioma,It was only less than glioma and meningioma.Most of the pituitary adenomas are benign,only a small part of aggressive,of which 0.1～0.2%eventually carcinogenesis,There is a close relationship between the prognosis of pituitary adenocarcinoma and its malignant degree.Pituitary adenomas were divided into functional adenoma and non functional adenoma,its clinical manifestations include occupying effect and endocrine lesions in two aspects,non functional adenoma has a higher incidence rate than functional adenoma.Incidence rate from high to low are:prolactinomas(PRL type),growth hormone adenoma(type GH),adrenocorticotropic hormone producing adenoma(ACTH),follicle stimulating hormone and luteinizing hormone adenoma(FSH&LH).The clinical symptoms of functional adenoma is mainly composed of hormone secretion disorder caused.Two adenomas can be found the occupying effect When the tumor has grown big enough.Pituitary adenoma caused by mutations in a series of pituitary key genes such as protein kinase C(PKC),P16,and growth arrest and DNA damage-45y(GADD45γ)has provoked continued attentions among endocrinologists due to its variability in clinical presentation and unpredictability of tumor growth.As showed in previous studies,pituitary adenoma can affect the body development in negative ways from various perspectives.Excess hormone secretion in pituitary caused by pituitary adenoma produce a series of metabolic disorder and visceral injury.On the contrary,other hormones present down-regulation because of compression of tumor which subsequently results in function decline of target glands.Currently,a wealth of studies has been conducted on the surgical treatment and chemotherapy of pituitary adenoma.Studies showed that both gene and protein expressions of certain regulatory factors present vital roles in the pituitary adenoma.It was found that P53 inhibits the generation of pituitary adenoma and this function could be restrained by pleomorphic adenoma gene-like 1(PLAGL1)under the joint action with RPRM,P21 and phorbol-12-myristate-13-acetate-induced Protein 1(PMAIP1).It is well acknowledged that over expression of growth arrest and DNA damage-45β(GADD45-beta)could inhibit tumor growth through activating apoptosis inhibiting factors,which indicating that GADD45-beta may also serve a potential inhibition to pituitary adenoma.Pituitary adenoma can lead to a variety of gene expression level raise or decline,most changes of which also shows regulatory effects on tumorigenesis.Although some studies were reported concerning effects of pituitary adenoma on potential target genes,there has no effective detection method through the flux way to systematically detect the gene and protein differential expressions caused by pituitary adenoma.The present study aims to investigate types and changes of gene expression in pituitary adenoma compared to normal pituitary through gene expression profiling.Subsequently,by establishing PPI(protein-protein interaction)network of differentially expressed genes(DEGs),we analyzed the effects of differential proteins on pituitary adenoma and the interactions among diverse differential proteins.We aim to study the pathogenesis of pituitary adenoma through screening the differential expressed genes(DEGs)and proteins between normal pituitary and pituitary adenoma,and analyzing the interactions among them.After acquisitioning gene expression profiling from public functional genomics data repository,DEGs were screened between normal pituitary and pituitary adenoma.The gene expression profile GSE26966 was downloaded from a public functional genomics data repository GEO.Among the total 23 samples been investigated,9 and 14 samples were respectively from normal pituitary and pituitary adenoma.The annotation information of all probes sets was provided by Affymetrix Human Genome U133A2.0 Array.For data processing and differential expression analysis,we converted the probe-level data in CEL files into expression value of probe matrix by RMA(robust multi-array average)in Affy package,and transferred the serial numbers into gene names by platform R/Bioconductor note package.Finally,as one gene having many corresponding probes,we calculated the average value of all expression value of probes as the expression value of a single gene.The Bayesian linear model of limma package in R software was used to identify DEGs in pituitary adenoma compared to normal pituitary.Only genes with the |log fold change| value larger than 1.5 and false discovery rate(FDR)less than 0.05 were selected as DEGs.In order to ensure the screened DEGs can well characterize the samples,clustering analysis and dendrogram for DEGs were established respectively.Up and down-regulated DEGs were further identified through gene ontology(GO)functional enrichment analysis.Subsequently,the DEGs were mapped to string database and then protein-protein interaction(PPI)networks of the up and down-regulated DEGs were constructed.The PPI network of the down-regulated DEGs presented a characteristic of centralization,and some node proteins of the network such as EGR1,STAT3,JUNB and FOS were the common transcription factors in cancer.Relatively,the PPI network of up-regulated DEGs showed a sparse status.Through the comparison between these two PPI networks,we found that down-regulated genes played a main role in pituitary adenoma.Thus,we focused on the analysis of functional modules in PPI network of down-regulated DEGs.Finally,functional modules of PPI network of down-regulated DEGs were analyzed.Totally,211 up-regulated and 413 down-regulated DEGs were screened between normal and pituitary adenomas samples.Down-regulated DEGs were associated with functions like immune response,hormone regulation and cell proliferation.Up-regulated genes were related to cation transport function.Five modules were acquired from the PPI network of the down-regulated DEGs.Transcription factors,such as STAT3,IL6,Bc16,EGR1,POU1F1,JUNB and FOS were the core nodes in functional modules.In summary,we succeeded to find the DEGs and proteins through screening gene expression profiling and PPI networks.Results of the present study indicated that low expression of hormone and immune related genes facilitated the occurrence of pituitary adenoma.Low expression of IL6 and STAT3 played pivotal roles in the dysimmunity of pituitary adenoma.Meanwhile,low expression of POU1F1 contributed to the pituitary hormone secretion decline.Pituitary adenomas are tumors occurred in the pituitary gland,which consists of benign type,malignant type and invasive type.If the tumor size is larger than 1 cm,the tumors are designated pituitary macroadenomas.In spite of the pathological types,pituitary macroadenomas often cause hyperpituitarism or hypopituitarism and a series of subsequent diseases.Although some pituitary microadenomas(less than 1 cm in size)may be remained untreatment if the tumors do not cause clinical symptoms,most pituitary macroadenomas require surgical intervention.Tumor tolerance indicates a condition that immune effector cells do not attack tumor cells;tumors thus grow out of control.The underlying mechanism of tumor tolerance is suggested that tumor specific regulatory T cells or/and tumor specific regulatory B cells develop in tumor tissue to inhibit the tumor specific effector cell function.Transforming growth factor(TGF)-β and interleukin(IL)-10 are two major immune regulatory molecules;by releasing which the tumor specific immune regulatory cells interfere with immune effector cell functions.Radiotherapy is one of the major remedies in tumor treatment.The therapeutic efficacy needs to be further improved.Probiotics can facilitate immune regulation.This study tests a hypothesis that radiotherapy inhibits interleukin(IL)-10-producing B cells(B10 cells)in pituitary adenomas.Patients with recurrentpituitary adenomas were treated with radiotherapy prior to surgery.B10 cells in tumor tissue were analyzed after surgical removal.The results showed that the frequency of B10 cells in pituitary adenoma tissue was significantly less in those treated with radiotherapy.The B10 cells from pituitary adenoma without irradiation showed high levels of HDAC1 and low levels of miR-98.Exposure B cells to radiation increased miR-98 expression;the latter inhibits IL-10 expression.A conclusioncould be drawn from the results:radiation suppresses IL-10 expression in B cells in pituitary adenomas via up regulation of miR-98 expression.