The role of PAQR3 gene promoter hypermethylation in breast cancer and prognosis

Golgi apparatus targeted therapy in cancer: Are we there yet?

Membrane trafficking within the Golgi apparatus plays a pivotal role in the intracellular transportation of lipids and proteins. Dysregulation of this process can give rise to various pathological manifestations, including cancer. Exploiting Golgi defects, cancer cells capitalise on aberrant membrane trafficking to facilitate signal transduction, proliferation, invasion, immune modulation, angiogenesis, and metastasis. Despite the identification of several molecular signalling pathways associated with Golgi abnormalities, there remains a lack of approved drugs specifically targeting cancer cells through the manipulation of the Golgi apparatus. In the initial section of this comprehensive review, the focus is directed towards delineating the abnormal Golgi genes and proteins implicated in carcinogenesis. Subsequently, a thorough examination is conducted on the impact of these variations on Golgi function, encompassing aspects such as vesicular trafficking, glycosylation, autophagy, oxidative mechanisms, and pH alterations. Lastly, the review provides a current update on promising Golgi apparatus-targeted inhibitors undergoing preclinical and/or clinical trials, offering insights into their potential as therapeutic interventions. Significantly more effort is required to advance these potential inhibitors to benefit patients in clinical settings.

The Emerging Roles and Mechanisms of PAQR3 in Human Cancer: Pathophysiology and Therapeutic Implications

Cancer was one of the common causes of death in the world, and it was increasing year by year. At present, Progestin and AdipoQ receptor family member 3 (PAQR3) was widely studied in cancer. It has been found that PAQR3 was down regulated in various cancers, such as the gastric cancer, osteosarcoma, glioma, hepatocellular carcinoma, acute lymphoblastic leukemia, laryngeal squamous cell carcinoma, esophageal cancer, breast cancer, non-small cell lung cancer, and colorectal cancer. The decreased expression of PAQR3 was associated with short overall survival and disease-free survival in patients with gastric cancer, hepatocellular carcinoma, laryngeal squamous cell carcinoma, esophageal cancer, breast cancer, and non-small cell lung cancer. PAQR3 could inhibit cancer progression by using the Ras/Raf/MEK/ERK, PI3/AKT, EMT and other mechanisms, and was negatively regulated by the miR-543, miR-15b-5p and miR-15b. The roles and signaling mechanisms of PAQR3, and the relationship between the expression of PAQR3 and prognosis in cancer progression are reviewed in this article, and provides new tumor marker and idea to guide cancer treatment.

Integrative pan-cancer analysis reveals the importance of PAQR family in lung cancer

BACKGROUND

The progestin and adipoQ receptors (PAQRs) family contains 11 genes involved in the regulation of metabolism and cancer development. However, a comprehensive understanding of the role of PAQRs in cancer remains largely scarce, and the associations between their expression levels and immune signatures also need to be researched.

METHODS

Here, we applied pan-cancer analysis to explore the associations between PAQRs expression and survival, tumor microenvironment (TME), and drug sensitivity from the UCSC Xena and CellMiner databases. Besides, we further studied the expression, survival and somatic mutations of PAQRs in lung cancer (LC) from TCGA database.

RESULTS

The results showed that PAQRs had significant heterogeneity with some upregulation and some downregulation in most tumors. Specifically, compared with PAQR3/5/6/9 and MMD2, ADIPOR1/2, PAQR4/7/8 and MMD had higher levels of average expression in all tumor types. PAQRs expression was greatly correlated with survival, immune subtypes, TME, and drug sensitivity. Furthermore, this research concentrated on analyzing the relationship of PAQRs expression with LC prognosis, and proved that ADIPOR2, PAQR4/9 and MMD were independent prognostic factors for LC patients. Finally, based on somatic mutation data, the genetic mutations in LC patients were majorly missense mutations, and TP53 and TTN had the top two highest mutation frequencies.

CONCLUSION

Collectively, PAQRs may serve as robust biomarkers to predict the prognosis and guide immunotherapy of tumors, especially LC, which enables novel ways for improving cancer treatment.

Integrated analysis reveals common DNA methylation patterns of alcohol-associated cancers: A pan-cancer analysis

Background: The role of alcohol in carcinogenesis has received increasing attention in recent years. Evidence shows its impacts on various aspects, including epigenetics alteration. The DNA methylation patterns underlying alcohol-associated cancers are not fully understood. Methods: We investigated the aberrant DNA methylation patterns in four alcohol-associated cancers based on the Illumina HumanMethylation450 BeadChip. Pearson coefficient correlations were identified between differential methylated CpG probes and annotated genes. Transcriptional factor motifs were enriched and clustered using MEME Suite, and a regulatory network was constructed. Results: In each cancer, differential methylated probes (DMPs) were identified, and 172 hypermethylated and 21 hypomethylated pan-cancer DMPs (PDMPs) were examined further. Annotated genes significantly regulated by PDMPs were investigated and enriched in transcriptional misregulation in cancers. The CpG island chr19:58220189-58220517 was hypermethylated in all four cancers and silenced in the transcription factor ZNF154. Various biological effects were exerted by 33 hypermethylated and seven hypomethylated transcriptional factor motifs grouped into five clusters. Eleven pan-cancer DMPs were identified to be associated with clinical outcomes in the four alcohol-associated cancers, which might provide a potential point of view for clinical outcome prediction. Conclusion: This study provides an integrated insight into DNA methylation patterns in alcohol-associated cancers and reveals the corresponding features, influences, and potential mechanisms.

Epigenetic study of early breast cancer (EBC) based on DNA methylation and gene integration analysis

Breast cancer (BC) is one of the leading causes of cancer-related deaths in women. The purpose of this study is to identify key molecular markers related to the diagnosis and prognosis of early breast cancer (EBC). The data of mRNA, lncRNA and DNA methylation were downloaded from The Cancer Genome Atlas (TCGA) dataset for identification of differentially expressed mRNAs (DEmRNAs), differentially expressed lncRNAs (DElncRNAs) and DNA methylation analysis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyzes were used to identify the biological functions of DEmRNAs. The correlation analysis between DNA methylation and DEmRNAs was carried out. Then, diagnostic analysis and prognostic analysis of identified DEmRNAs and DElncRNAs were also performed in the TCGA database. Subsequently, methylation state verification for identified DEmRNAs was performed in the GSE32393 dataset. In addition, real-time polymerase chain reaction (RT-PCR) in vitro verification of genes was performed. Finally, AC093110.1 was overexpressed in human BC cell line MCF-7 to verify cell proliferation and migration. In this study, a total of 1633 DEmRNAs, 750 DElncRNAs and 8042 differentially methylated sites were obtained, respectively. In the Venn analysis, 11 keys DEmRNAs (ALDH1L1, SPTBN1, MRGPRF, CAV2, HSPB6, PITX1, WDR86, PENK, CACNA1H, ALDH1A2 and MME) were we found. ALDH1A2, ALDH1L1, HSPB6, MME, MRGPRF, PENK, PITX1, SPTBN1, WDR86 and CAV2 may be considered as potential diagnostic gene biomarkers in EBC. Strikingly, CAV2, MME, AC093110.1 and AC120498.6 were significantly actively correlated with survival. Methylation state of identified DEmRNAs in GSE32393 dataset was consistent with the result in TCGA. AC093110.1 can affect the proliferation and migration of MCF-7. ALDH1A2, ALDH1L1, HSPB6, MME, MRGPRF, PENK, PITX1, SPTBN1, WDR86 and CAV2 may be potential diagnostic gene biomarkers of EBC. Strikingly, CAV2, MME, AC093110.1 and AC120498.6 were significantly actively correlated with survival. The identification of these genes can help in the early diagnosis and treatment of EBC. In addition, AC093110.1 can regulate SPTBN1 expression and play an important role in cell proliferation and migration, which provides clues to clarify the regulatory mechanism of EBC.

Characterization of the Golgi scaffold protein PAQR3, and its role in tumor suppression and metabolic pathway compartmentalization

The Golgi apparatus is critical in the compartmentalization of signaling cascades originating from the cytoplasmic membrane and various organelles. Scaffold proteins, such as progestin and adipoQ receptor (PAQR)3, specifically regulate this process, and have recently been identified in the Golgi apparatus. PAQR3 belongs to the PAQR family, and was recently described as a tumor suppressor. Accumulating evidence demonstrates PAQR3 is downregulated in different cancers to suppress its inhibitory effects on malignant potential. PAQR3 functions biologically through the pathological regulation of altered signaling pathways. Significant cell proliferation networks, including Ras proto-oncogene (Ras)/mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt), insulin, and vascular endothelial growth factor, are closely controlled by PAQR3 for physiologically relevant effects. Meanwhile, genetic/epigenetic susceptibility and environmental factors, may have functions in the downregulation of PAQR3 in human cancers. This study aimed to assess the subcellular localization of PAQR3 and determine its topological features and functional domains, summarizing its effects on cell signaling compartmentalization. The pathophysiological functions of PAQR3 in cancer pathogenesis, metabolic diseases, and developmental ailments were also highlighted.

Associations of the BRAF V600E Mutation and PAQR3 Protein Expression with Papillary Thyroid Carcinoma Clinicopathological Features

The BRAF^V600E mutation is the most prevalent genetic event in patients with papillary thyroid cancer (PTC). However, no study has investigated the expression of PAQR3 in papillary thyroid tissues in relation to the BRAF^V600E mutation and the clinicopathological features of PTC patients. Furthermore, the potential associations of the BRAF^V600E mutation, PAQR3 expression and clinicopathological parameters in the cancerous tissues of PTC patients have not been investigated. This study was conducted on 60 patients with PTC who were treated surgically at our institution from 2017 to 2018. PCR was used to amplify DNA by the amplification refractory mutation system (ARMS) method to detect BRAF^V600E gene mutations. In addition, immunohistochemical techniques were utilized to assess PAQR3 expression in tumor tissue sections. The BRAF^V600E mutation was associated with lymph node metastasis (LNM, p < 0.05) but not with other clinicopathological features. Low PAQR3 expression was associated with extrathyroidal extension and LNM (χ² = 7.143, p = 0.009; χ² = 6.459, p = 0.014, respectively). Furthermore, a statistically significant association was observed between chronic lymphocytic thyroiditis and LNM (χ² = 5.275, p = 0.0250). A linear relationship between the BRAF^V600E mutation and PAQR3 protein expression has not been identified. These factors may be independent risk factors of extrathyroidal extension and LNM in PTC and be used to indicate the invasiveness of PTC tumors. Higher quality, multivariate analyses based on larger samples from around the world are urgently needed to further validate and revise our findings in the future.

Selected Golgi-Localized Proteins and Carcinogenesis: What Do We Know?

The role of the Golgi apparatus in carcinogenesis still remains unclear. A number of structural and functional cis-, medial-, and trans-Golgi proteins as well as a complexity of metabolic pathways which they mediate may indicate a central role of the Golgi apparatus in the development and progression of cancer. Pleiotropy of cellular function of the Golgi apparatus makes it a "metabolic heart" or a relay station of a cell, which combines multiple signaling pathways involved in carcinogenesis. Therefore, any damage to or structural abnormality of the Golgi apparatus, causing its fragmentation and/or biochemical dysregulation, results in an up- or downregulation of signaling pathways and may in turn promote tumor progression, as well as local nodal and distant metastases. Three alternative or parallel models of spatial and functional Golgi organization within tumor cells were proposed: (1) compacted Golgi structure, (2) normal Golgi structure with its increased activity, and (3) the Golgi fragmentation with ministacks formation. Regardless of the assumed model, the increased activity of oncogenesis initiators and promoters with inhibition of suppressor proteins results in an increased cell motility and migration, increased angiogenesis, significantly activated trafficking kinetics, proliferation, EMT induction, decreased susceptibility to apoptosis-inducing factors, and modulating immune response to tumor cell antigens. Eventually, this will lead to the increased metastatic potential of cancer cells and an increased risk of lymph node and distant metastases. This chapter provided an overview of the current state of knowledge of selected Golgi proteins, their role in cytophysiology as well as potential involvement in tumorigenesis.

Aberrant promoter methylation of the PAQR3 gene is associated with prostate cancer

Methylation markers are promising tools for diagnosis, prognosis and targeted treatment of cancer. In prostate carcinoma, aberrant promoter hypermethylation occurs earlier in the disease course and more consistently than recurrent somatic mutations. PAQR3, a tumor suppressor gene, was recently found to be downregulated in prostate cancer cell lines. We hypothesized that promoter methylation could be responsible for PAQR3 silencing in prostate cancer tissues. We aimed to investigate PAQR3 promoter methylation in prostate cancer by comparing it to benign prostatic hyperplasia (BPH). A total of 154 human prostate tissue samples, including 92 cases with prostate cancer and 62 cases with BPH, were examined by methylation-specific PCR. Clinicopathological correlation between PAQR3 promoter methylation and prognostically relevant variables was studied by statistical analysis. Promoter methylation of PAQR3 was significantly more frequent in prostate carcinoma compared to BPH (73.9% vs. 25.8%, p<0.01). The high prevalence of PAQR3 methylation in cancer foci was also confirmed with microdissection technique in 12 samples of prostate adenocarcinoma. PAQR3 hypermethylation was associated with perineural invasion (p=0.03), an adverse clinicopathological feature of prostate cancer. We concluded that PAQR3 can be a promising methylation marker candidate for the detection and monitoring of prostate cancer.

PAQR3 overexpression suppresses the aggressive phenotype of esophageal squamous cell carcinoma cells via inhibition of ERK signaling

Progestin and adipoQ receptor family member 3 (PAQR3) has exhibited anticancer activity in multiple malignancies. However, its expression and function in esophageal squamous cell carcinoma (ESCC) is still elusive. In this work, we examined the expression of PAQR3 in 40 surgically resected ESCC specimens and their adjacent normal tissues. The expression of PAQR3 in ESCC cell lines was measured after treatment with the demethylating agent 5-aza-2'-deoxycytidine (5-Aza-CdR). The effects of overexpression of PAQR3 on cell proliferation, colony formation, invasion, and tumorigenesis were investigated. It was found that the PAQR3 mRNA level was significantly lower in ESCC than that in adjacent normal tissues (P=0.0318). Low PAQR3 expression was significantly associated with more advanced TNM stage (P=0.0093) and absent lymph node involvement (P=0.0324). Compared to normal esophageal epithelial cells, ESCC cells had significantly lower levels of PAQR3. 5-Aza-CdR treatment led to an induction of PAQR3 in ESCC cells. Enforced expression of PAQR3 significantly inhibited ESCC cell proliferation, colony formation and invasion. Moreover, PAQR3 overexpression blocked cell cycle transition from G1 to S phase, which was associated with induction of p27 and p21 and reduction of cyclin D1, CDK4, and CDK2. Mechanistically, overexpression of PAQR3 suppressed the phosphorylation of ERK1/2 in ESCC cells. In vivo tumorigenic studies confirmed that PAQR3 overexpression retarded the growth of ECA-109 xenograft tumors and inhibited the activation of ERK signaling. Taken together, PAQR3 is epigenetically silenced in ESCC and restoration of PAQR3 suppresses the aggressive phenotype of ESCC cells. Therefore, PAQR3 may represent a potential target for the treatment of ESCC.

A synthetic peptide hijacks the catalytic subunit of class I PI3K to suppress the growth of cancer cells

Activation of class I Phosphoinositide 3-kinases (PI3Ks) by mutation or overexpression closely correlates with the development of various human cancers. Class I PI3Ks are heterodimers composed of p110 catalytic subunits and regulatory subunits represented by p85. PAQR3 has been found to inhibit p110α activity by blocking its interaction with p85. In this study, we identified the N-terminal 6-55 amino acid residues of PAQR3 being sufficient for its interaction with p110α. A synthetic peptide, P6-55, that contains the N-terminus of PAQR3 could disrupt the interactions of p110α with both PAQR3 and p85. The activity of PI3K was also inhibited by P6-55, accompanied by significant inhibition of cancer cell proliferation. In a xenograft mouse model, P6-55 was able to reduce tumor growth in vivo. Furthermore, P6-55 was capable of inhibiting the elevated basal PI3K activity of H1047R, a hotspot mutation found in many types of human cancers. The cell proliferation and migration of cancer cells bearing H1047R mutation were also reduced by P6-55. In conclusion, our study provides a proof of concept that blocking the interaction of p110α with p85 by a peptide can serve as a new strategy to inhibit the oncogenic activity of PI3K in cancer therapy.

PAQR3 Inhibits the Proliferation and Tumorigenesis in Esophageal Cancer Cells

Progestin and adipoQ receptor family member III (PAQR3), a member of the PAQR family, is frequently downregulated in different types of human cancer. However, its expression and functions in esophageal cancer are still unknown. This study aimed to explore the expression of PAQR3 in esophageal cancer cell lines and to investigate the role of PAQR3 in the development of esophageal cancer. Our data showed that PAQR3 is expressed in low amounts in human esophageal cancer cell lines. Overexpression of PAQR3 significantly suppressed the proliferation, migration, and invasion of esophageal cancer cells. In addition, overexpression of PAQR3 downregulated the protein expression levels of RAF1, p-MEK1, and p-ERK1/2 in esophageal cancer cells. Furthermore, overexpression of PAQR3 attenuated the tumor growth in a tumor xenograft model. In conclusion, we demonstrated that overexpression of PAQR3 suppresses cell proliferation, migration, and invasion in esophageal cancer in vitro and in vivo. Therefore, PAQR3 may act as a therapeutic target for human esophageal cancer.

PAQR3 inhibits the proliferation, migration and invasion in human glioma cells

Progestin and AdipoQ Receptor 3 (PAQR3), a member of the PAQR family, is down-regulated in several types of cancers and has been closely associated with tumor progression and development. However, little is known about the functions of PAQR3 in the tumorigenesis of human glioma. Therefore, in this report, we investigated the role of PAQR3 in human glioma. Our results showed that the expression of PAQR3 was significantly reduced in human glioma tissues and cell lines. PAQR3 overexpression inhibited the proliferation of glioma cells in vitro and attenuated tumor xenograft growth in vivo. In addition, PAQR3 overexpression suppressed the migration and invasion of glioma cells, as well as prevented the EMT process. Mechanistic studies demonstrated that PAQR3 overexpression significantly down-regulated the levels of phosphorylated PI3K and Akt in U251 cells. In conclusion, these results demonstrated that PAQR3 inhibited the proliferation, migration and invasion in glioma cells, at least in part, through the inactivation of PI3K/Akt signaling pathway. Therefore, PAQR3 may be a therapeutic target for the treatment of glioma.