MiR-21-5p Targets PIK3R1 To Regulate IκBa/MMP12/MMP14 Signaling Pathway Inhibiting Invasion And Progression Of Prolactinoma

Background:Prolactinoma(PRL)is considered to be a benign tumor.However,part of PRL has the biological characteristics of malignant tumors-invading its surrounding tissues,such as cavernous sinuses,sphenoid sinuses,dura mater,etc.,known as aggressive PRL.The invasive PRL can destroy its surrounding tissues,such as the normal structure of the saddle area and skull base.Therefore,complete surgical resection in the clinic is extremely difficult.At the same time,because of its characteristics of easy recurrence after surgery,the treatment of the aggressive PRL often uses radiotherapy and chemotherapy.So,it is urgent and important to explore the molecular mechanism of PRL invasiveness and find potential therapeutic targets.Studies have shown that mi R-21-5p can affect the invasion and metastasis of many tumors,such as breast cancer and pancreatic cancer.And it has been reported that mi R-21-5p can affect tumor invasion and metastasis in glioma;it was also noted that the expression of mi R-21 in pituitary adenomas correlated with tumor invasion and size.However,so far,it remains unclear about the mechanism of mi R-21-5p on PRL.It is well-known that phosphoinositide-3-kinase regulatory subunit 1(PI3K)pathway dysregulation is frequent in cancer.As an important component of the PI3 K pathway,PIK3R1 plays an important role in tumor progression.Recently,it has been reported that PIK3R1 is abnormally expressed in breast and gastric cancers,and it has been confirmed that the abnormal expression of PIK3R1 is associated with the proliferation,differentiation and migration of tumor cells.However,the role of PIK3R1 in PRL and its regulatory mechanism are unclear.Therefore,it is of great significance to investigate whether mi R-21-5p can affect the progression of PRL and its related regulatory mechanisms by regulating the PI3 K signaling pathway for PRL treatment and new strategies for prevention.Materials and Methods:1.Clinical specimens12 fresh PRL tumor samples were collected from PRL patients hospitalized in the First Affiliated Hospital of Nanchang University from January 2018 to November2021.We set invasive PRL: tumors break through the capsule and invade into the cavernous sinus even further;non-invasive: tumors do not enter the sella.Invasive PRL sampling sites included two parts: intrasellar – close to the pituitary gland;cavernous sinus – far from the pituitary gland;and non-invasive PRL took only the intrasellar part.None of the patients had received chemotherapy,radiotherapy,interventional therapy,drug-targeted therapy or immunotherapy before surgery.Specimens were all anonymous.All the samples’ source and processing procedures comply with the requirements of the Ethics Committee of First Affiliated Hospital of Nanchang University.2.MethodsQR-PCR and Western blot were used to detect the expression of mi R-21-5p,PIK3R1,MMP12,MMP14,IκBa and p-IκBa protein in clinical tissue samples and cell experiments.TUNEL,CCK8 and Transwell were used to detect the ability of cell proliferation,invasion and migration.In vivo animal experiments used subcutaneous tumor formation models in nude mice,tumor volume and size were monitored uninterrupted during tumor growth,and Ki67 protein expression was detected using immunohistochemistry.Bioinformatics methods were used to analyze the hub genes on PRL invasion and progression.Results:The results of clinical samples analysis suggested that mi R-21-5p expression was higher in invasive PRL than in non-invasive PRL.In vitro and in vivo experiments showed that overexpression of mi R-21-5p promoted PRL cell proliferation and invasion,migration and inhibited apoptosis.Bioinformatic analysis showed that PIK3R1 was a hub gene on PRL progression and invasion.In addition,overexpression of PIK3R1 was able to significantly attenuate the effects of mi R-21-5p in promoting cell proliferation,invasion and migration,and inhibiting apoptosis.The ability of PIK3R1 to inhibit proliferation,invasion and migration of PRL cell lines was correlated with the expression levels of IκBa and its phosphorylation,MMP12,and MMP14.Conclusions:In summary,mi R-21-5p affects the IκBa/MMP12/MMP14 signaling pathway by targeting PIK3R1 and regulates the invasion and progression of prolactinomas,providing an important theoretical basis for clinical prevention and treatment for invasive PRL.