Knockdown of PTTG1 inhibits the growth and invasion of lung adenocarcinoma cells through regulation of TGFB1/SMAD3 signaling

The Role of RAC2 and PTTG1 in Cancer Biology

Several molecular pathways are likely involved in the regulation of cancer stem cells (CSCs) via Ras-associated C3 botulinum toxin substrate 2, RAC2, and pituitary tumor-transforming gene 1 product, PTTG1, given their roles in cellular signaling, survival, proliferation, and metastasis. RAC2 is a member of the Rho GTPase family and plays a crucial role in actin cytoskeleton dynamics, reactive oxygen species production, and cell migration, contributing to epithelial-mesenchymal transition (EMT), immune evasion, and therapy resistance. PTTG1, also known as human securin, regulates key processes such as cell cycle progression, apoptosis suppression, and EMT, promoting metastasis and enhancing cancer cell survival. This article aims to describe the molecular pathways involved in the proliferation, invasiveness, and drug response of cancer cells through RAC2 and PTTG1, aiming to clarify their respective roles in neoplastic process dependencies. Both proteins are involved in critical signaling pathways, including PI3K/AKT, TGF-β, and NF-κB, which facilitate tumor progression by modulating CSC properties, angiogenesis, and immune response. This review highlights the molecular mechanisms by which RAC2 and PTTG1 influence tumorigenesis and describes their potential and efficacy as prognostic biomarkers and therapeutic targets in managing various neoplasms.

Identification and validation of tryptophan-related gene signatures to predict prognosis and immunotherapy response in lung adenocarcinoma reveals a critical role for PTTG1

Introduction

Tryptophan metabolism is strongly associated with immunosuppression and may influence lung adenocarcinoma prognosis as well as tumor microenvironment alterations.

Methods

Sequencing datasets were obtained from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) database. Two different clusters were identified by consensus clustering, and prognostic models were established based on differentially expressed genes (DEGs) in the two clusters. We investigated differences in mutational landscapes, enrichment pathways, immune cell infiltration, and immunotherapy between high- and low-risk scoring groups. Single-cell sequencing data from Bischoff et al. were used to identify and quantify tryptophan metabolism, and model genes were comprehensively analyzed. Finally, PTTG1 was analyzed at the pan-cancer level by the pan-TCGA cohort.

Results

Risk score was defined as an independent prognostic factor for lung adenocarcinoma and was effective in predicting immunotherapy response in patients with lung adenocarcinoma. PTTG1 is one of the key genes, and knockdown of PTTG1 in vitro decreases lung adenocarcinoma cell proliferation and migration and promotes apoptosis and down-regulation of tryptophan metabolism regulators in lung adenocarcinoma cells.

Discussion

Our study revealed the pattern and molecular features of tryptophan metabolism in lung adenocarcinoma patients, established a model of tryptophan metabolism-associated lung adenocarcinoma prognosis, and explored the roles of PTTG1 in lung adenocarcinoma progression, EMT process, and tryptophan metabolism.

Integrative analysis of single-cell and bulk RNA-sequencing data revealed T cell marker genes based molecular sub-types and a prognostic signature in lung adenocarcinoma

Immunotherapy has emerged as a promising modality for addressing advanced or conventionally drug-resistant malignancies. When it comes to lung adenocarcinoma (LUAD), T cells have demonstrated significant influence on both antitumor activity and the tumor microenvironment. However, their specific contributions remain largely unexplored. This investigation aimed to delineate molecular subtypes and prognostic indicators founded on T cell marker genes, thereby shedding light on the significance of T cells in LUAD prognosis and precision treatment. The cellular phenotypes were identified by scrutinizing the single-cell data obtained from the GEO repository. Subsequently, T cell marker genes derived from single-cell sequencing analyses were integrated with differentially expressed genes from the TCGA repository to pinpoint T cell-associated genes. Utilizing Cox analysis, molecular subtypes and prognostic signatures were established and subsequently verified using the GEO dataset. The ensuing molecular and immunological distinctions, along with therapy sensitivity between the two sub-cohorts, were examined via the ESTIMATE, CIBERSORT, and ssGSEA methodologies. Compartmentalization, somatic mutation, nomogram development, chemotherapy sensitivity prediction, and potential drug prediction analyses were also conducted according to the risk signature. Additionally, real-time qPCR and the HPA database corroborated the mRNA and protein expression patterns of signature genes in LUAD tissues. In summary, this research yielded an innovative T cell marker gene-based signature with remarkable potential to prognosis and anticipate immunotherapeutic outcomes in LUAD patients.

Clinical significance of securin expression in solid cancers: A PRISMA-compliant meta-analysis of published studies and bioinformatics analysis based on TCGA dataset

BACKGROUND

Numerous studies have investigated the clinical significance of securin expression in solid cancers; however, the results have been inconsistent. Hence, we performed a meta-analysis of published studies to assess the clinical value of securin expression in patients with solid cancers.

METHODS

The Chinese National Knowledge Infrastructure, Web of Science, PubMed, and EMDASE databases were searched for eligible studies (from inception up to April 2021). Bioinformatics analysis based on The Cancer Genome Atlas dataset was also performed to evaluate the prognostic value of securin expression.

RESULTS

A total of 25 articles with 26 studies were included in the meta-analysis. The results of the meta-analysis implied that high securin expression was positively correlated with unfavorable overall survival (OS) (hazard ratio = 1.52, 95% CI, 1.33-1.73; P < .001) and lymph node metastasis (odd ratio = 2.96, 95% CI, 2.26-3.86; P < .001). Consistently, our bioinformatics analysis showed that increased securin expression was associated with worse OS and shorter disease-free survival in cancer patients.

CONCLUSION

Our study indicated that securin overexpression was positively associated with metastasis and inversely related to the prognosis of patients with solid cancers. However, additional high-quality studies should be conducted to validate these findings.

Prognostic Significance of PTTG1 and Its Methylation in Lung Adenocarcinoma

Pituitary tumor-transforming gene-1 (PTTG1), one type of DNA repair-related gene, has been reported to be dysregulated in several tumors and serve as a tumor promotor. Previously, the oncogenic roles of PTTG1 were also reported in lung adenocarcinoma (LUAD). However, the prognostic values of PTTG1 in LUAD and the possible mechanism of its dysregulation have not been clarified. We analyzed TCGA datasets and reported that PTTG1 expression showed a distinct increase within LUAD specimens in comparison with nontumor specimens. Further survival study revealed that patients containing a great PTTG1 level had noticeably less overall survival and progression-free survival as compared with patients containing a low PTTG1 level. Multivariate analyses confirmed that PTTG1 expression was a factor of prognosis that is independent in terms of LUAD patients. Besides, PTTG1 methylation had a negative regulation on PTTG1, so PTTG1 had a high expressing level in LUAD tissues. However, the relation between hypermethylation and overall survival was not demonstrated using TCGA datasets. In addition, we observed that LUAD specimens with advanced stages exhibited a higher level of PTTG1. Finally, the dysregulated genes related to PTTG1 expression were screened, and KEGG assays revealed that the above genes were involved in the p53 signaling pathway, indicating the possible regulatory function of PTTG1 in the p53 signaling pathway. Overall, our findings suggest that PTTG1 may serve as an efficient clinical biomarker and a therapeutic target for patients suffering from LUAD.

PTTG1 knockdown enhances radiation-induced antitumour immunity in lung adenocarcinoma

AIM

Ionizing radiation (IR) can induce local and systemic antitumour immune responses to some degree and augment immunotherapeutic efficacy. IR may also increase residual tumour cell invasion and elicit immunosuppression in the tumour microenvironment (TME). It remains poorly understand, whether IR leads to immune negative response or invasive capacity increases in lung adenocarcinoma (LAC).

MATERIALS AND METHODS

RNA interference (RNAi) was used to silence pituitary tumour-transforming gene-1 (PTTG1) and SMAD3 expression in LAC cells. A coculture system of tumour cells and PBMCs was constructed. Cells were exposed to different doses (0, 4 and 8 Gy) of X-ray irradiation. Flow cytometric analysis and Transwell assays were applied. An orthotopic Lewis lung cancer (LLC) mouse tumour model was established. Bioluminescence imaging (BLI) was used. LLC tumours were exposed to a single 15 Gy dose of X-ray irradiation.

KEY FINDINGS

PTTG1 knockdown reinforced the inhibitory effect of IR on the invasive ability of A549 cells and enhanced the antitumour T cell immunity induced by IR via the transforming growth factor-β1 (TGF-β1)/SMAD3 pathway. Positive antitumour immune response and immunosuppression were simultaneously triggered by a single 15 Gy dose of local tumour irradiation. PTTG1 knockdown weakened invasive capacity and promoted the immune response balance induced by IR to tilt towards active immunity, which contributed to reduce metastasis and prolonged overall survival (OS) in orthotopic LLC tumour-bearing mouse.

SIGNIFICANCE

Targeted blockade of PTTG1 and the TGF-β1/SMAD3 pathway may ameliorate the immunosuppressive TME and enhance the systemic antitumour immune response induced by a single high-dose IR treatment.

Bladder Tumor Subtype Commitment Occurs in Carcinoma In Situ Driven by Key Signaling Pathways Including ECM Remodeling

Basal and luminal subtypes of invasive bladder tumors have significant prognostic and predictive impacts for patients. However, it remains unclear whether tumor subtype commitment occurs in noninvasive urothelial lesions or in carcinoma in situ (CIS) and which gene pathways are important for bladder tumor progression. To understand the timing of this commitment, we used gene expression and protein analysis to create a global overview of 36 separate tissues excised from a whole bladder encompassing urothelium, noninvasive urothelial lesions, CIS, and invasive carcinomas. Additionally investigated were matched CIS, noninvasive urothelial lesions, and muscle-invasive bladder cancers (MIBC) from 22 patients. The final stage of subtype commitment to either a luminal or basal MIBC occurred at the CIS transition. For all tissues combined, hierarchical clustering of subtype gene expression revealed three subtypes: "luminal," "basal," and a "luminal p53-/extracellular matrix (ECM)-like" phenotype of ECM-related genes enriched in tumor-associated urothelium, noninvasive urothelial lesions, and CIS, but rarely invasive, carcinomas. A separate cohort of normal urothelium from noncancer patients showed significantly lower expression of ECM-related genes compared with tumor-associated urothelium, noninvasive urothelial lesions, and CIS. A PanCancer Progression Panel of 681 genes unveiled pathways specific for the luminal p53-/ECM-like cluster, for example, ECM remodeling, angiogenesis, epithelial-to-mesenchymal transition, cellular discohesion, cell motility involved in tumor progression, and cell proliferation and oncogenic ERBB2/ERBB3 signaling for invasive carcinomas. In conclusion, this study provides insights into bladder cancer subtype commitment and associated signaling pathways, which could help predict therapy response and enhance our understanding of therapy resistance. SIGNIFICANCE: This study demonstrates that CIS is the stage of commitment for determining MIBC tumor subtype, which is relevant for patient prognosis and therapy response.

Identification of 5-Gene Signature Improves Lung Adenocarcinoma Prognostic Stratification Based on Differential Expression Invasion Genes of Molecular Subtypes

Background

The acquisition of invasive tumor cell behavior is considered to be the cornerstone of the metastasis cascade. Thus, genetic markers associated with invasiveness can be stratified according to patient prognosis. In this study, we aimed to identify an invasive genetic trait and study its biological relevance in lung adenocarcinoma.

Methods

250 TCGA patients with lung adenocarcinoma were used as the training set, and the remaining 250 TCGA patients, 500 ALL TCGA patients, 226 patients with GSE31210, 83 patients with GSE30219, and 127 patients with GSE50081 were used as the verification data sets. Subtype classification of all TCGA lung adenocarcinoma samples was based on invasion-associated genes using the R package ConsensusClusterPlus. Kaplan-Meier curves, LASSO (least absolute contraction and selection operator) method, and univariate and multivariate Cox analysis were used to develop a molecular model for predicting survival.

Results

As a consequence, two molecular subtypes for LUAD were first identified from all TCGA all data sets which were significant on survival time. C1 subtype with poor prognosis has higher clinical characteristics of malignancy, higher mutation frequency of KRAS and TP53, and a lower expression of immune regulatory molecules. 2463 differentially expressed invasion genes between C1 and C2 subtypes were obtained, including 580 upregulation genes and 1883 downregulation genes. Functional enrichment analysis found that upregulated genes were associated with the development of tumor pathways, while downregulated genes were more associated with immunity. Furthermore, 5-invasion gene signature was constructed based on 2463 genes, which was validated in four data sets. This signature divided patients into high-risk and low-risk groups, and the LUDA survival rate of the high-risk group is significantly lower than that of the low-risk group. Multivariate Cox analysis revealed that this gene signature was an independent prognostic factor for LUDA. Compared with other existing models, our model has a higher AUC.

Conclusion

In this study, two subtypes were identified. In addition, we developed a 5-gene signature prognostic risk model, which has a good AUC in the training set and independent validation set and is a model with independent clinical characteristics. Therefore, we recommend using this classifier as a molecular diagnostic test to assess the prognostic risk of patients with LUDA.

aarF domain containing kinase 5 gene promotes invasion and migration of lung cancer cells through ADCK5-SOX9-PTTG1 pathway

AarF domain containing kinase 5 (ADCK5) is a member of an atypical kinase family and overexpressed in many carcinomas including lung cancer, while the function of this protein has not been elucidated. Here we investigated the mechanism of ADCK5 involved in regulating invasion and migration of lung cancer cells, and showed that ADCK5 might regulate the expression of tumor oncogene human pituitary tumor transforming gene-1 (PTTG1) by phosphorylating transcription factor SOX9, therefore enhancing the migration and invasion capabilities of lung cancer cells. Mutagenesis of potential serine phosphorylation sites on SOX9 indicated that serine 181 might be required to maintain transcription activation of SOX9 as well as increase PTTG1 levels. The serine 181 site of SOX9 is in a motif that is targeted by ADCK5. The ADCK5-SOX9-PTTG1 pathway might be a potential therapeutic target for lung cancer.

Analysis and Identification of Tumorigenic Targets of MicroRNA in Cancer Cells by Photoreactive Chemical Probes

Photoactive RNA probes have unique advantages in the identification of microRNA (miR) targets due to their ability for efficient conjugation to the target sequences by covalent crosslinking, providing stable miR-mRNA complexes for further analysis. Here, we report a highly efficient and straightforward method for miR target identification that is based on photo-reactive chemical probes and RNA-seq technology (denotes PCP-Seq). UV reactive probes were prepared by incorporating psoralen in the specific position of the seed sequence of miR. Cancer cells that were transfected with the miR probes were treated with UV, following the isolation of poly(A) RNA and sequencing of the transcriptome. Quantitative analysis of RNA-seq reads and subsequent validation by qPCR, dual luciferase assay as well as western blotting confirmed that PCP-Seq could highly efficiently identify multiple targets of different miRs in the lung cancer cell line, such as targets PTTG1 and PTGR1 of miR-29a and ILF2 of miR-34a. Collectively, our data showed that PCP-Seq is a robust strategy for miR targets identification, and unique in the identification of the targets that escape degradation by miRISC and maintain normal cellular level, although their translation is repressed.

Distinct expression pattern and prognostic values of pituitary tumor transforming gene family genes in non-small cell lung cancer

Members of the pituitary tumor transforming gene (PTTG) family, including PTTG1, PTTG2 and PTTG3P, exhibit pivotal roles in the onset and progression of certain types of human cancer. However, to the best of our knowledge, a systematic study regarding the expression pattern and the prognostic values of PTTG family genes in non-small cell lung cancer (NSCLC) remains to be performed. The expression levels of PTTG family genes in NSCLC were successively determined using the Gene Expression Profiling Interactive Analysis, UALCAN and Oncomine databases. Subsequently, the Kaplan-Meier plotter database was used to assess the prognostic value of the PTTG family genes in patients with NSCLC, and to determine the associations between PTTG expression levels and the prognosis of patients based on different clinicopathological features, including cancer stage, grade, chemotherapy, radiotherapy, lymph node status, smoking history, and sex. PTTG1 was identified to be significantly upregulated in NSCLC in all three databases, whereas PTTG2 and PTTG3P were significantly upregulated in NSCLC in only the UALCAN database. Patients with NSCLC with higher expression levels of the three PTTG genes demonstrated shorter overall survival times. In summary, the results of the present study suggested that increased expression of PTTG family genes may serve as promising prognostic biomarkers for patients with NSCLC.

miR-655-3p inhibits cell migration and invasion by targeting pituitary tumor-transforming 1 in non-small cell lung cancer

miR-655-3p functions as a tumor suppressor in tumor metastases; however, its role and mechanism in regulating cell migration and invasion of non-small cell lung cancer (NSCLC) remain unclear. Here, we found that miR-655-3p expression was markedly decreased in the NSCLC cell lines A549, NCI-H1650, PC14/b, NCI-H1299, and HPAEpiC compared to levels observed in normal human lung fibroblasts. miR-655-3p overexpression significantly inhibited migration and invasion of A549 and PC14/b cells, and pituitary tumor-transforming 1 (PTTG1) expression was up-regulated in the NSCLC cells. Luciferase reporter assays indicated that PTTG1 was a direct target of miR-655-3p. Additionally, PTTG1 overexpression alleviated the inhibitory effect of miR-655-3p on migration and invasion abilities in A549 and PC14/b cells. In conclusion, miR-655-3p inhibits NSCLC migration and invasion by targeting PTTG1, suggesting that miR-655-3p may serve as a therapeutic target to provide a new approach for the clinical treatment of NSCLC.

Integrated Analysis of Transcriptome and Prognosis Data Identifies FGF22 as a Prognostic Marker of Lung Adenocarcinoma

Lung adenocarcinoma is one of the most common cancers worldwide. However, the molecular mechanisms of lung adenocarcinoma development are still unclear. This study aimed to investigate the expression profiles of anti-lung cancer target genes in different cancer stages and to explore their functions in tumor development. Lung adenocarcinoma transcriptome and clinical data were downloaded from Genomic Data Commons Data Portal, and the anti-lung cancer target genes were retrieved from the Thomson Reuters Integrity database. The results showed that 16 anti-lung target genes were deregulated in all stages. Among these target genes, fibroblast growth factor 22 showed the most important role in transcription regulatory networks. Further analysis revealed that APC, BRIP1, and PTTG1 may regulate fibroblast growth factor 22 and subsequently influence MAPK signaling pathway, Rap1 signaling pathways, and other tumorigenic processes in all stages. Moreover, high fibroblast growth factor 22 expression leads to poor overall survival (hazard ratio = 1.55, P = .019). These findings provide valuable information for the pathological research and treatment of lung adenocarcinoma. Future studies are needed to verify these results.

Aberrant CpG-methylation affects genes expression predicting survival in lung adenocarcinoma

Lung adenocarcinoma (LUAD) is a common diagnosed disease with high-mortality rate, and its prognostic implications are under discovered. DNA methylation aberrations are not only an important event for dysregulation of gene expression during tumorigenesis but also a revolution in epigenetics by identifying key prognostic biomarkers for multiple cancers. In this study, we analyzed methylation status of 485 578 CpG sites and RNA-seq transcriptomes of 20 532 genes for 1095 LUAD samples in TCGA database. The association between DNA methylation and the prognostic value of the corresponding gene expression was identified as well. In total, ten aberrantly methylated and dysregulated genes (AURKA, BLK, CNTN2, HMGA1, PTTG1, TNS4, DAPK2, MFSD2A, THSD1, and WNT7A) were highlighted which were significantly correlated with overall survival of 492 LUAD patients, which were all reported as tumor-associated genes in other various cancers and worthy of further investigated and might be used as therapeutic targets for LUAD. Together, methylation aberrances regulate gene expression level during tumorigenesis and influence prognosis of LUAD patients. Integrating knowledge of epigenetics and expression of genes can be useful for an in-depth understanding of cancer mechanism and for the eventual purpose of precisely prognostic and therapeutic target verification.

Targeting the PTTG1 oncogene impairs proliferation and invasiveness of melanoma cells sensitive or with acquired resistance to the BRAF inhibitor dabrafenib

The pituitary tumor transforming gene 1 (PTTG1) is implicated in tumor growth, metastasis and drug resistance. Here, we investigated the involvement of PTTG1 in melanoma cell proliferation, invasiveness and response to the BRAF inhibitor (BRAFi) dabrafenib. We also preliminary assessed the potential value of circulating PTTG1 protein to monitor melanoma patient response to BRAFi or to dabrafenib plus trametinib. Dabrafenib-resistant cell lines (A375R and SK-Mel28R) were more invasive than their drug-sensitive counterparts (A375 and SK-Mel28), but expressed comparable PTTG1 levels. Dabrafenib abrogated PTTG1 expression and impaired invasion of the extracellular matrix (ECM) in A375 and SK-Mel28 cells. In contrast, it affected neither PTTG1 expression in A375R and SK-Mel28R cells, nor ECM invasion in the latter cells, while further stimulated A375R cell invasiveness. Assessment of proliferation and ECM invasion in control and PTTG1-silenced A375 and SK-Mel28 cells, exposed or not to dabrafenib, demonstrated that the inhibitory effects of this drug were, at least in part, dependent on its ability to down-regulate PTTG1 expression. PTTG1-silencing also impaired proliferation and invasiveness of A375R and SK-Mel28R cells, and counteracted dabrafenib-induced stimulation of ECM invasion in A375R cells. Further experiments performed in A375R cells indicated that PTTG1-silencing impaired cell invasiveness through inhibition of MMP-9 and that PTTG1 expression and ECM invasion could be also reduced by the CDK4/6 inhibitor LEE011. PTTG1 targeting might, therefore, represent a useful strategy to impair proliferation and metastasis of melanomas resistant to BRAFi. Circulating PTTG1 also appeared to deserve further investigation as biomarker to monitor patient response to targeted therapy.

Pituitary tumor transforming gene-1 in non-small cell lung cancer: Clinicopathological and immunohistochemical analysis

Pituitary tumor transforming gene-1 (PTTG1) is a novel oncogene and overexpressed in a wide variety of human cancers. However, the clinical and prognostic significance of PTTG1 in non-small cell lung cancer (NSCLC) is still unknown. The expression status of PTTG1 in NSCLC at the publicly available GEO databases (GSE19804) was observed. The mRNA and protein expression of PTTG1 in NSCLC tissues and cell lines was detected by qRT-PCR and Western blot, and the association between PTTG1 expression and clinicopathological factors was analyzed by immunohistochemistry. In our Results, PTTG1 was one of genes overexpressed in NCSLC samples compared with paired adjacent normal lung samples in microarray data (GSE19804). PTTG1 mRNA and protein expressions were increased in NSCLC tissues and cell lines. PTTG1 protein expression was correlated with malignant status and poor prognosis of NSCLC patients. In conclusion, PTTG1 is correlated with NSCLC progression and as an independent poor prognostic factor in NSCLC patients.