الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Unusual proliferation of lung cells causes lung cancer, a serious health problem. Lung cancer is thought to have the highest death rate of all cancer types and is the primary cause of cancer-related deaths worldwide. Lung cancer is a leading cause of death due to its fast spread. A significant decrease in cancer-related morbidity and death depends on the early detection of lung cancer. The main cause of lung cancer is tobacco use, which includes using electronic cigarettes, cigars, and cigarettes themselves. However, non-smokers are equally susceptible. Additional risk factors include exposure to secondhand smoke, air pollution, genetic predisposition, and a history of chronic lung disorders, as well as occupational risks such asbestos, radon, and certain chemicals.
Small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC) are the two classes into which this malignancy is classified histologically.Fifty-five percent of lung tumors are NSCLC, while fifteen percent are SCLC. Based on the origin of the tumor and the kind of cellular pathology seen, Lung adenocarcinoma (LUAD), squamous cell carcinoma (LUSC), and large cell carcinoma (LCC) are subtypes of non-small cell lung cancer (NSCLC). Physical examinations, imaging (such as CT scans and magnetic resonance imaging), bronchoscopy examinations, tissue biopsies for histopathology analysis and subtype determination, and molecular testing to detect particular genetic mutations or biomarkers to inform optimal treatment choices are among the diagnostic techniques for lung cancer.
The class of non-coding RNAs known as microRNAs (miRNAs) has an average length of 22 nucleotides and is involved in the regulation of gene expression. Most miRNAs originate from DNA sequences and are transcribed into primary miRNAs, which are then processed into precursor miRNAs and mature miRNAs. The majority of the time, miRNAs bind to target mRNAs’ 3′ untranslated region (3′ UTR) to cause translational repression and mRNA destruction. Nevertheless, it has also been discovered that miRNAs interact with other areas, including as the 5′ UTR, coding sequence, and gene promoters. MiRNAs have the ability to control transcription and initiate translation under specific circumstances. Numerous factors, including the subcellular localization of miRNAs, the abundance of miRNAs and target mRNAs, and the affinity of miRNA-mRNA interactions, influence the dynamic interaction between miRNAs and their target genes. miRNAs have the ability to attach to proteins, such as Argonautes, or be secreted into extracellular fluids and delivered to target cells via vesicles like exosomes. Extracellular miRNAs facilitate cell-to-cell communication by acting as chemical messengers. It has been demonstrated that miRNA influences the onset, diagnosis, and prognosis of lung cancer.Numerous malignancies have been studied in relation to miR–762. For instance, it has been proposed that upregulating miR-762 is associated with nasopharyngeal cancer progression by encouraging the proliferation and invasion of tumor cells. Furthermore, there was a strong correlation found between miR–762 and the genes related to neurological impairment. Furthermore, miR-762 is crucial in modulating the oncogenesis of breast cancer.
Part of the family of signaling channels known to regulate organ size and development is the Hippo signaling system, which has been conserved throughout evolution. A serine/threonine kinase signaling cascade that has been preserved throughout evolution, the Hippo pathway was first discovered in fruit flies (Drosophila melanogaster). The upstream signal molecule that binds to the co-regulatory protein SAV1 and activates MST1/2 does so when the Hippo pathway is triggered. The co-regulatory protein MOB1 is then bound by phosphorylated LATS1/2. Following that, YAP/TAZ’s phosphorylation is triggered and it attaches to the scaffold protein 14-3-3. After being ubiquitinated, the YAP/TAZ is in the cytoplasm and is broken down by the proteasome. Lastly, YAP/TAZ’s biological activity is suppressed. The phosphorylation cascade is impacted and the Hippo pathway is either inhibited or rendered inactive when cancer occurs. The cytoplasm is where unphosphorylated YAP/TAZ reaches the nucleus. Combining with the TEADs transcription family, it functions as a transcriptional coactivator, boosting cell proliferation and anti-apoptosis and synergistically promoting the expression of target genes. Several miRNAs have been shown in numerous studies to negatively influence the Hippo tumor-suppressor signaling pathway and to facilitate the growth of tumors.
A highly conserved basic Helix-Loop-Helix (bHLH) transcriptional regulator is called twist-related protein 1 (TWIST1). In several cancer cell lines, its overexpression induces EMT and CSC characteristics.Numerous malignancies, such as gliomas, sarcomas, melanoma, and carcinomas of the breast and squamous tissue, have elevated TWIST1 expression. Overexpression of TWIST1 blocks the p53 pathway, which is responsible for Myc-induced cell death.TWIST1 overexpression primes EMT and suppresses E-cadherin expression, indicating that TWIST1 can cause metastasis via fostering EMT.
The TGFβreceptor complex phosphorylates SMAD3, a crucial intracellular mediator of TGFβ signaling, at the C terminus. A number of other kinases phosphorylate different locations within the Smad protein by using SMAD3 as a substrate. For an extended period, TGF-β has been considered a facilitator of tumor advancement in advanced cancer by inhibiting immune monitoring, triggering the epithelial to mesenchyme transition (EMT), and augmenting cell motility and the transcription of metastasis-promoting proteins. SMAD3 plays an indispensable role in these multifaceted pathway activities and thus functions as a tumor promoter.
One of the enolase enzymes involved in the glycolytic pathway that is present in nerve and neuroendocrine tissues is called neuron-specific enolase (NSE). After central nervous system damage, NSE is one of the particular markers showing nervous system impairment and has the highest activity in brain tissue cells. NSE can pass past the blood-brain barrier and damaged cell membrane and into the blood and cerebrospinal fluid. The use of NSE as a biomarker for SCLC and NSCLC is well established. In neurogenic tumors and neuroendocrine cells, NSE is overexpressed.
In this study, the expression profiles of miR-762,MST1,LATS2,YAP,TWIST1 and SMAD3 which were determined using real time PCR, the concentration of YAP protein (pg/ml) that was evaluated by ELISA and NSE enzyme level that was evaluated by ECLIA were evaluated as biomarkers in 20 apparently healthy control,30 non-cancer patients with chronic pulmonary inflammatory diseases (such as bronchial asthma, emphysema, and obstructive pulmonary diseases) and 50 patients newly diagnosed with lung cancer. In addition, those biomarkers were related to the clinicopathological characteristics of lung cancer patients and to the clinical characteristics of chronic inflammatory patients. Moreover, miR-762 was correlated to Hippo signaling pathway.
The present study showed that the expression of each of miR-762,YAP, TWIST1, SMAD3 and the level of NSE enzyme were significantly elevated in lung cancer patients when compared to control group. On the other hand the expression of each of MST1 and LATS2 as well as the concentration of phosphorylated YAP protein were significantly lowered in lung cancer patients as compared to control group. Moreover, significant relations between tumor size and MST1 gene expression, between grade and TWIST1, SMAD3 as well as YAP gene expression, between gender and YAP gene expression, between smoking and YAP gene expression, between age and LATS2 and between family history and SMAD3 gene expression in lung cancer patients were observed.
Furthermore, there were significant negative correlations between MiR-762 and each of phosphorylated YAP protein, MST1 and LATS2.
ROC curve analysis indicated the validity of using MiR-762, MST1, LATS2, YAP, TWIST1, SMAD3 gene expression,YAP protein (pg/ml) as well as NSE enzyme levels (ng/ml) as diagnostic biomarkers for lung cancer.
Kaplan-meier survival curve analysis showed that higher expression of each of YAP, TWIST1 and SMAD3 genes was associated with poor disease free survival. Also, higher expression of SMAD3 gene was associated with worse overall survival.