PLAC8 Localizes to the Inner Plasma Membrane of Pancreatic Cancer Cells and Regulates Cell Growth and Disease Progression through Critical Cell-Cycle Regulatory Pathways

Identification of Tissue miRNA Signatures for Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC), a neoplasm of the gastrointestinal tract, is the most common pancreatic malignancy (90%) and the fourth highest cause of cancer mortality worldwide. Surgery intervention is currently the only strategy able to offer an advantage in terms of overall survival, but prognosis remains poor even for operated patients. Therefore, the development of robust biomarkers for early diagnosis and prognostic stratification in clinical practice is urgently needed. In this work, we investigated deregulated microRNAs (miRNAs) in tissues from PDAC patients with high (G3) or low (G2) histological grade and with (N+) or without (N-) lymph node metastases. miRNA expression profiling was performed by a comprehensive PCR array and subsequent validation by RT-qPCR. The results showed a significant increase in miR-1-3p, miR-31-5p, and miR-205-5p expression in G3 compared to G2 patients (** p < 0.01; *** p < 0.001; *** p < 0.001). miR-518d-3p upregulation and miR-215-5p downregulation were observed in N+ compared to N- patients. A statistical analysis performed using OncomiR program showed the significant involvement (p < 0.05) of two miRNAs (miR-31 and miR-205) in the histological grade of PDAC patients. Also, an expression analysis in PDAC patients showed that miR-31 and miR-205 had the highest expression at grade 3 compared with normal and other tumor grades. Overall, survival plots confirmed that the overexpression of miR-31 and miR-205 was significantly correlated with decreased survival in TCGA PDAC clinical samples. A KEGG pathway analysis showed that all three miRNAs are involved in the regulation of multiple pathways, including the Hippo signaling, adherens junction and microRNAs in cancer, along with several target genes. Based on in silico analysis and experimental validation, our study suggests the potential role of miR-1-3p, miR-31-5p, and miR-205-5p as useful clinical biomarkers and putative therapeutic targets in PDAC, which should be further investigated to determine the specific molecular processes affected by their aberrant expression.

A benzochalcone derivative synchronously induces apoptosis and ferroptosis in pancreatic cancer cells

Background

Pancreatic cancer is a highly aggressive and lethal disease with limited treatment options. In this study, we investigated the potential therapeutic effects of compound KL-6 on pancreatic cancer cells.

Methods

The study involved assessing the inhibitory effects of KL-6 on cell proliferation, clonogenic potential, cell cycle progression, apoptosis, migration, and invasion. Additionally, we examined the action mechanism of KL-6 by RNA-seq and bioinformatic analysis and validated by qRT-PCR and western blot in pancreatic cancer cells.

Results

Our results demonstrated that KL-6 effectively inhibited the growth of pancreatic cancer cells in a dose-dependent manner. It induced G2/M phase cell cycle arrest and apoptosis, disrupting the cell cycle progression and promoting cell death. KL-6 also exhibited inhibitory effects on cell migration and invasion, suggesting its potential to suppress the metastatic properties of pancreatic cancer cells. Furthermore, KL-6 modulated the expression of genes involved in various cancer-related pathways including apoptosis and ferroptosis.

Conclusion

These findings collectively support the potential of KL-6 as a promising therapeutic option for pancreatic cancer treatment. Further research is needed to fully understand the underlying mechanisms and evaluate the clinical efficacy of KL-6 in pancreatic cancer patients.

The Novel-Natural-Killer-Cell-Related Gene Signature Predicts the Prognosis and Immune Status of Patients with Hepatocellular Carcinoma

The current understanding of the prognostic significance of natural killer (NK) cells and their tumor microenvironment (TME) in hepatocellular carcinoma (HCC) is limited. Thus, we screened for NK-cell-related genes by single-cell transcriptome data analysis and developed an NK-cell-related gene signature (NKRGS) using multi-regression analyses. Patients in the Cancer Genome Atlas cohort were stratified into high- and low-risk groups according to their median NKRGS risk scores. Overall survival between the risk groups was estimated using the Kaplan-Meier method, and a NKRGS-based nomogram was constructed. Immune infiltration profiles were compared between the risk groups. The NKRGS risk model suggests significantly worse prognoses in patients with high NKRGS risk (p < 0.05). The NKRGS-based nomogram showed good prognostic performance. The immune infiltration analysis revealed that the high-NKRGS-risk patients had significantly lower immune cell infiltration levels (p < 0.05) and were more likely to be in an immunosuppressive state. The enrichment analysis revealed that immune-related and tumor metabolism pathways highly correlated with the prognostic gene signature. In this study, a novel NKRGS was developed to stratify the prognosis of HCC patients. An immunosuppressive TME coincided with the high NKRGS risk among the HCC patients. The higher KLRB1 and DUSP10 expression levels correlated with the patients' favorable survival.

Investigation of Underlying Biological Association and Targets between Rejection of Renal Transplant and Renal Cancer

Background

Post-renal transplant patients have a high likelihood of developing renal cancer. However, the underlying biological mechanisms behind the development of renal cancer in post-kidney transplant patients remain to be elucidated. Therefore, this study aimed to investigate the underlying biological mechanism behind the development of renal cell carcinoma in post-renal transplant patients.

Methods

Next-generation sequencing data and corresponding clinical information of patients with clear cell renal cell carcinoma (ccRCC) were obtained from The Cancer Genome Atlas Program (TCGA) database. The microarray data of kidney transplant patients with or without rejection response was obtained from the Gene Expression Omnibus (GEO) database. In addition, statistical analysis was conducted in R software.

Results

We identified 55 upregulated genes in the transplant patients with rejection from the GEO datasets (GSE48581, GSE36059, and GSE98320). Furthermore, we conducted bioinformatics analyses, which showed that all of these genes were upregulated in ccRCC tissue. Moreover, a prognosis model was constructed based on four rejection-related genes, including PLAC8, CSTA, AIM2, and LYZ. The prognosis model showed excellent performance in prognosis prediction in a ccRCC cohort. In addition, the machine learning algorithms identified 19 rejection-related genes, including PLAC8, involved in ccRCC occurrence. Finally, the PLAC8 was selected for further research, including its clinical and biological role.

Conclusion

In all, our study provides novel insight into the transition from the rejection of renal transplant to renal cancer. Meanwhile, PLAC8 could be a potential biomarker for ccRCC diagnosis and prognosis in post-kidney transplant patients.

PLAC8 contributes to the malignant behaviors of cervical cancer cells by activating the SOX4-mediated AKT pathway

Cervical cancer (CC) is the primary cancer-related cause of morbidity and mortality in women. Previous studies have shown that placenta-specific 8 (PLAC8) has different functions in multiple malignancies. This study aimed to explore the function and regulatory mechanism of PLAC8 in CC. Bioinformatics and immunohistochemical analyses demonstrated that PLAC8 was significantly upregulated in CC tissues compared with normal tissues. Gain/loss-of-function experiments showed that siRNA-mediated knockdown of PLAC8 suppressed cell migration and invasion, while PLAC8 overexpression promoted cell motility. Moreover, PLAC8 was revealed to affect the epithelial-mesenchymal transition (EMT) process by upregulating epithelial (E)-cadherin and decreasing the expression of mesenchymal markers of EMT, including vimentin, zinc finger E-box binding homeobox 1 (ZEB1), neural (N)-cadherin, matrix metalloproteinase-9 (MMP-9), and MMP-2 in PLAC8-silenced cells. PLAC8 activated the AKT pathway, as proven by the downregulation of p-AKT_Ser473 and p-AKT_Thr308 expression after PLAC8 knockdown. Furthermore, PLAC8 overexpression upregulated the expression of sex-determining region Y-related high-mobility group box transcription factor 4 (SOX4), which is reported to mediate the activation of the AKT pathway, and SOX4 deficiency reversed the cellular functions caused by PLAC8 overexpression. Overall, the present study indicates that PLAC8 may facilitate CC development by activating the SOX4-mediated AKT pathway, suggesting that PLAC8 may serve as a potential biomarker for CC treatment.

Phospholipid scramblase 1: a protein with multiple functions via multiple molecular interactors

Phospholipid scramblase 1 (PLSCR1) is the most studied protein of the scramblase family. Originally, it was identified as a membrane protein involved in maintaining plasma membrane asymmetry. However, studies conducted over the past few years have shown the involvement of PLSCR1 in several other cellular pathways. Indeed, PLSCR1 is not only embedded in the plasma membrane but is also expressed in several intracellular compartments where it interacts with a diverse repertoire of effectors, mediators, and regulators contributing to distinct cellular processes. Although most PLSCR1 interactors are thought to be cell-type specific, PLSCR1 often exerts its regulatory functions through shared mechanisms, including the trafficking of different molecules within intracellular vesicles such as endosomes, liposomes, and phagosomes. Intriguingly, besides endogenous proteins, PLSCR1 was also reported to interact with exogenous viral proteins, thereby regulating viral uptake and spread. This review aims to summarize the current knowledge about the multiple roles of PLSCR1 in distinct cellular pathways.

Identification of Four Novel Prognostic Biomarkers and Construction of Two Nomograms in Adrenocortical Carcinoma: A Multi-Omics Data Study via Bioinformatics and Machine Learning Methods

Background: Adrenocortical carcinoma (ACC) is an orphan tumor which has poor prognoses. Therefore, it is of urgent need for us to find candidate prognostic biomarkers and provide clinicians with an accurate method for survival prediction of ACC via bioinformatics and machine learning methods.

Methods: Eight different methods including differentially expressed gene (DEG) analysis, weighted correlation network analysis (WGCNA), protein-protein interaction (PPI) network construction, survival analysis, expression level comparison, receiver operating characteristic (ROC) analysis, and decision curve analysis (DCA) were used to identify potential prognostic biomarkers for ACC via seven independent datasets. Linear discriminant analysis (LDA), K-nearest neighbor (KNN), support vector machine (SVM), and time-dependent ROC were performed to further identify meaningful prognostic biomarkers (MPBs). Cox regression analyses were performed to screen factors for nomogram construction.

Results: We identified nine hub genes correlated to prognosis of patients with ACC. Furthermore, four MPBs (ASPM, BIRC5, CCNB2, and CDK1) with high accuracy of survival prediction were screened out, which were enriched in the cell cycle. We also found that mutations and copy number variants of these MPBs were associated with overall survival (OS) of ACC patients. Moreover, MPB expressions were associated with immune infiltration level. Two nomograms [OS-nomogram and disease-free survival (DFS)-nomogram] were established, which could provide clinicians with an accurate, quick, and visualized method for survival prediction.

Conclusion: Four novel MPBs were identified and two nomograms were constructed, which might constitute a breakthrough in treatment and prognosis prediction of patients with ACC.

PLAC8 Overexpression Promotes Lung Cancer Cell Growth via Wnt/β-Catenin Signaling

The PLAC8 expression in lung cancer tissues and in vitro grown lung cancer cells, as well as the involvement of the Wnt/β-Catenin signaling pathway, was investigated in this process. PLAC8 protein expression in human lung cancer tissues and lung tumor cells of different strains was discovered using immunohistochemistry staining and Western blot, respectively. Animal models of PLAC8 overexpression and knockdown were created using lentivirus. The development in tumor tissue was seen both in vitro and vivo. The Wnt/β-Catenin signaling pathway played an important part in this process, as shown by the dual luciferase reporter gene system. PLAC8 expression was elevated in lung cancer tissues and plasma and decreased in plasma after lung tumor resection. PLAC8 upregulation promotes cell proliferation in vivo and in vitro, while PLAC8 downregulation inhibits cell viability and proliferation. The results of the dual luciferase reporter gene system suggest that PLAC8 can significantly activate the Wnt/β-Catenin signaling pathway in cells and can conduct signaling through it. A potential treatment targeting the prognosis of lung cancer patients may be PLAC8 overexpression, which promotes the lung cancer cell proliferation through controlling the Wnt/β-Catenin signaling pathway.

Genomewide CRISPR knockout screen identified PLAC8 as an essential factor for SADS-CoVs infection

Zoonotic transmission of coronaviruses poses an ongoing threat to human populations. Endemic outbreaks of swine acute diarrhea syndrome coronavirus (SADS-CoV) have caused severe economic losses in the pig industry and have the potential to cause human outbreaks. Currently, there are no vaccines or specific antivirals against SADS-CoV, and our limited understanding of SADS-CoV host entry factors could hinder prompt responses to a potential human outbreak. Using a genomewide CRISPR knockout screen, we identified placenta-associated 8 protein (PLAC8) as an essential host factor for SADS-CoV infection. Knockout of PLAC8 abolished SADS-CoV infection, which was restored by complementing PLAC8 from multiple species, including human, rhesus macaques, mouse, pig, pangolin, and bat, suggesting a conserved infection pathway and susceptibility of SADS-CoV among mammals. Mechanistically, PLAC8 knockout does not affect viral entry; rather, knockout cells displayed a delay and reduction in viral subgenomic RNA expression. In a swine primary intestinal epithelial culture (IEC) infection model, differentiated cultures have high levels of PLAC8 expression and support SADS-CoV replication. In contrast, expanding IECs have low levels of PLAC8 expression and are resistant to SADS-CoV infection. PLAC8 expression patterns translate in vivo; the immunohistochemistry of swine ileal tissue revealed high levels of PLAC8 protein in neonatal compared to adult tissue, mirroring the known SADS-CoV pathogenesis in neonatal piglets. Overall, PLAC8 is an essential factor for SADS-CoV infection and may serve as a promising target for antiviral development for potential pandemic SADS-CoV.

Long noncoding RNA HOXD-AS1 promotes the progression of pancreatic cancer through miR-664b-3p/PLAC8 axis

Pancreatic cancer (PC) is one of the most common malignancies worldwide. There are no effective early diagnosis and therapeutic methods for PC. Mounting evidence has shown that lncRNAs promote PC progression. For instance, HOXD-AS1 acts as an oncogenic lncRNA in some digestive tumors. However, its role in PC is unknown. This study aimed to investigate the role of HOXD-AS1 in PC and its underlying mechanisms. Quantitative reverse transcription (qRT‑PCR) was used to measure the expression levels of HOXD-AS1, miR-664b-3p, and PLAC8. CCK-8, colony formation, wound healing, and transwell assays were used to assess the effect of HOXD-AS1 on the proliferation, invasion and migration of PC cells. Dual-luciferase reporter and cell function rescue assays were used to verify the regulation relationship of miR-664b-3p and HOXD-AS1 or PLAC8. HOXD-AS1 was significantly upregulated in PC tissues than in paired adjacent tissues. Moreover, HOXD-AS1 was related to the advanced TNM stage. Meanwhile, HOXD-AS1 promoted the proliferation, invasion, and migration of PC cells. Mechanically, HOXD-AS1 upregulated PLAC8 by targeting miR-664b-3p. In conclusion, HOXD-AS1 was upregulated in PC tissues, promoting the proliferation, invasion, and migration of PC cells via the miR-664b-3p/PLAC8 axis.

Novel insight into pancreatic adenocarcinoma pathogenesis using liquid association analysis

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy associated with a poor prognosis. High-throughput disease-related-gene expression data provide valuable information on gene interaction, which consequently lead to deeper insight about pathogenesis. The co-expression analysis is a common approach that is used to investigate gene interaction. However, such an approach solely is inadequate to reveal the complexity of the gene interaction. The three-way interaction model is known as a novel approach applied to decode the complex relationship between genes.

METHODS

In the current study, the liquid association method was used to capture the statistically significant triplets involved in the PDAC pathogenesis. Subsequently, gene set enrichment and gene regulatory network analyses were performed to trace the biological relevance of the statistically significant triplets.

RESULTS

The results of the current study suggest that "response to estradiol" and "Regulation of T-cell proliferation" are two critical biological processes that may be associated with the PDAC pathogenesis. Additionally, we introduced six switch genes, namely Lamc2, Klk1, Nqo1, Aox1, Tspan1, and Cxcl12, which might be involved in PDAC triggering.

CONCLUSION

In the current study, for the first time, the critical genes and pathways involved in the PDAC pathogenesis were investigated using the three-way interaction approach. As a result, two critical biological processes, as well as six potential biomarkers, were suggested that might be involved in the PDAC triggering. Surprisingly, strong evidence for the biological relevance of our results can be found in the literature.

Ribosomal Protein S6: A Potential Therapeutic Target against Cancer?

Ribosomal protein S6 (RPS6) is a component of the 40S small ribosomal subunit and participates in the control of mRNA translation. Additionally, phospho (p)-RPS6 has been recognized as a surrogate marker for the activated PI3K/AKT/mTORC1 pathway, which occurs in many cancer types. However, downstream mechanisms regulated by RPS6 or p-RPS remains elusive, and the therapeutic implication of RPS6 is underappreciated despite an approximately half a century history of research on this protein. In addition, substantial evidence from RPS6 knockdown experiments suggests the potential role of RPS6 in maintaining cancer cell proliferation. This motivates us to investigate the current knowledge of RPS6 functions in cancer. In this review article, we reviewed the current information about the transcriptional regulation, upstream regulators, and extra-ribosomal roles of RPS6, with a focus on its involvement in cancer. We also discussed the therapeutic potential of RPS6 in cancer.

Construction of a Pearson- and MIC-Based Co-expression Network to Identify Potential Cancer Genes

The weighted gene co-expression network analysis (WGCNA) method constructs co-expressed gene modules based on the linear similarity between paired gene expressions. Linear correlations are the main form of similarity between genes, however, nonlinear correlations still existed and had always been ignored. We proposed a modified network analysis method, WGCNA-P + M, which combines Pearson's correlation coefficient and the maximum information coefficient (MIC) as the similarity measures to assess the linear and nonlinear correlations between genes, respectively. Taking two real datasets, GSE44861 and liver hepatocellular carcinoma (TCGA-LIHC), as examples, we compared the gene modules constructed by WGCNA-P + M and WGCNA from four perspectives: the "Usefulness" score, GO enrichment analysis on genes in the gray module, prediction performance of the top hub gene, survival analysis and literature reports on different hub genes. The results showed that the modules obtained by WGCNA-P + M are more biological meaningful, the hub genes obtained from WGCNA-P + M have more potential cancer genes.

Multifaced roles of PLAC8 in cancer

The role of PLAC8 in tumorigenesis has been gradually elucidated with the development of research. Although there are common molecular mechanisms that enforce cell growth, the impact of PLAC8 is varied and can, in some instances, have opposite effects on tumorigenesis. To systematically understand the role of PLAC8 in tumors, the molecular functions of PLAC8 in cancer will be discussed by focusing on how PLAC8 impacts tumorigenesis when it arises within tumor cells and how these roles can change in different stages of cancer progression with the ultimate goal of suppressing PLAC8-relevant cancer behavior and related pathologies. In addition, we highlight the diversity of PLAC8 in different tumors and its functional output beyond cancer cell growth. The comprehension of PLAC8's molecular function might provide new target and lead to the development of novel anticancer therapies.

Gain-of-function p53R172H mutation drives accumulation of neutrophils in pancreatic tumors, promoting resistance to immunotherapy

Tumor genotype can influence the immune microenvironment, which plays a critical role in cancer development and therapy resistance. However, the immune effects of gain-of-function Trp53 mutations have not been defined in pancreatic cancer. We compare the immune profiles generated by KrasG12D-mutated mouse pancreatic ductal epithelial cells (PDECs) engineered genetically to express the Trp53R172H mutation with their p53 wild-type control. KrasG12D/+;Trp53R172H/+ tumors have a distinct immune profile characterized by an influx of CD11b+Ly6G+ neutrophils and concomitant decreases in CD3+ T cells, CD8+ T cells, and CD4+ T helper 1 cells. Knockdown of CXCL2, a neutrophil chemokine, in the tumor epithelial compartment of CRISPR KrasG12D/+;Trp53R172H/+ PDEC tumors reverses the neutrophil phenotype. Neutrophil depletion of mice bearing CRISPR KrasG12D/+;Trp53R172H/+ tumors augments sensitivity to combined CD40 immunotherapy and chemotherapy. These data link Trp53R172H to the presence of intratumoral neutrophils in pancreatic cancer and suggest that tumor genotypes could inform selection of affected individuals for immunotherapy.

Overcoming Osimertinib Resistance in Advanced Non-small Cell Lung Cancer

Osimertinib is used as a first-line treatment for metastatic non-small cell lung cancer with positive epidermal growth factor receptor mutations based on the results of the FLAURA trial. However, as with any other epidermal growth factor receptor tyrosine kinase inhibitor, resistance also develops for osimertinib. Various genetic aberrations associated with the molecular heterogeneity of cancer cells contribute to osimertinib resistance. It is also important to choose an appropriate subsequent treatment for osimertinib-resistant non-small cell lung cancer. In this overview, we discuss the underlying mechanisms of osimertinib resistance and the efficacy of possible subsequent treatment measures.

PLAC8 promotes the autophagic activity and improves the growth priority of human trophoblast cells

Autophagy plays an important role in the normal development and function of trophoblast cells and is precisely regulated during pregnancy. Dysregulated autophagy contributes to the abnormal proliferation of trophoblasts, which is closely related to the occurrence of pregnancy-related diseases. Placenta specific 8 (PLAC8, Onzin) is a multifaceted protein proven to promote autophagy and potentiate various tumor progression. Its role in trophoblasts remains elusive. In our present study, PLAC8 expression was detected in tissues of first-trimester placentas (n = 5), term placentas (n = 5), choriocarcinoma (n = 5), and placental site trophoblastic tumor (n = 5). PLAC8 expression was increased in gestational neoplasms compared with normal pregnancies. mCherry-EGFP-LC3B reporter and transmission electron microscopy confirmed PLAC8 promoted the autophagic flux of human trophoblast cells. Both gain-of-function and loss-of-function experiments demonstrated PLAC8-regulated autophagy-related genes, including ATG5, ATG12, and Beclin-1. In addition, our data showed that PLAC8 co-localized with p53 and promoted its degradation, and p53 re-expression partially abrogated the PLAC8-induced autophagy activity. Furthermore, the overexpression of PLAC8 promoted cell viability and proliferation, acting as a protective mechanism of trophoblasts against the cytotoxicity of etoposide (VP-16). Such a phenomenon was effectively abrogated by autophagy inhibitors 3-methyladenine (3-MA) and chloroquine (CQ). In conclusion, PLAC8-induced autophagy to promote the proliferation of trophoblasts. This study provided insights into the mechanism of PLAC8-induced autophagy in trophoblasts, which is significant for a wide range of gestational diseases and may contribute to developing novel treatment strategies for trophoblastic diseases.

PLAC8 promotes adriamycin resistance via blocking autophagy in breast cancer

Adriamycin (ADM) is currently one of the most effective chemotherapeutic agents in breast cancer treatment. However, growing resistance to ADM could lead to treatment failure and poor outcome. PLAC8 was reported as a novel highly conserved protein and functioned as an oncogene or tumour suppressor in various tumours. Here, we found higher PLAC8 expression was correlated with worse outcome and aggressive phenotype in breast cancer. Breast cancer patients with higher PLAC8 expression showed potential ADM resistance. In vitro experiments further confirmed that PLAC8 inhibited by siRNA or enforced overexpression by infecting pcDNA3.1(C)‐PLAC8 plasmid correspondingly decreased or increased ADM resistance. Subsequently, we demonstrated that ectopic PLAC8 expression in MCF‐7/ADMR cell blocked the accumulation of the autophagy‐associated protein LC3 and resulted in cellular accumulation of p62. Rapamycin‐triggered autophagy significantly increased cell response to ADM, while the autophagy inhibitor 3‐MA enhanced ADM resistance. 3‐MA and PLAC8 could synergistically cause ADM resistance via blocking the autophagy process. Additionally, the down‐regulation of p62 by siRNA attenuated the activation of autophagy and PLAC8 expression in breast cancer cells. Thus, our findings suggest that PLAC8, through the participation of p62, inhibits autophagy and consequently results in ADM resistance in breast cancer. PLAC8/p62 pathway may act as novel therapeutic targets in breast cancer treatment and has potential clinical application in overcoming ADM resistance.

Identification and Validation of a Novel Prognosis Prediction Model in Adrenocortical Carcinoma by Integrative Bioinformatics Analysis, Statistics, and Machine Learning

Adrenocortical carcinoma (ACC) is a rare malignancy with poor prognosis. Thus, we aimed to establish a potential gene model for prognosis prediction of patients with ACC. First, weighted gene co-expression network (WGCNA) was constructed to screen two key modules (blue: P = 5e-05, R^2 = 0.65; red: P = 4e-06, R^2 = -0.71). Second, 93 survival-associated genes were identified. Third, 11 potential prognosis models were constructed, and two models were further selected. Survival analysis, receiver operating characteristic curve (ROC), Cox regression analysis, and calibrate curve were performed to identify the best model with great prognostic value. Model 2 was further identified as the best model [training set: P < 0.0001; the area under curve (AUC) value was higher than in any other models showed]. We further explored the prognostic values of genes in the best model by analyzing their mutations and copy number variations (CNVs) and found that MKI67 altered the most (12%). CNVs of the 14 genes could significantly affect the relative mRNA expression levels and were associated with survival of ACC patients. Three independent analyses indicated that all the 14 genes were significantly associated with the prognosis of patients with ACC. Six hub genes were further analyzed by constructing a PPI network and validated by AUC and concordance index (C-index) calculation. In summary, we constructed and validated a prognostic multi-gene model and found six prognostic biomarkers, which may be useful for predicting the prognosis of ACC patients.

Autophagy Process in Trophoblast Cells Invasion and Differentiation: Similitude and Differences With Cancer Cells

Early human placental development begins with blastocyst implantation, then the trophoblast differentiates and originates the cells required for a proper fetal nutrition and placental implantation. Among them, extravillous trophoblast corresponds to a non-proliferating trophoblast highly invasive that allows the vascular remodeling which is essential for appropriate placental perfusion and to maintain the adequate fetal growth. This process involves different placental cell types as well as molecules that allow cell growth, cellular adhesion, tissular remodeling, and immune tolerance. Remarkably, some of the cellular processes required for proper placentation are common between placental and cancer cells to finally support tumor growth. Indeed, as in placentation trophoblasts invade and migrate, cancer cells invade and migrate to promote tumor metastasis. However, while these processes respond to a controlled program in trophoblasts, in cancer cells this regulation is lost. Interestingly, it has been shown that autophagy, a process responsible for the degradation of damaged proteins and organelles to maintain cellular homeostasis, is required for invasion of trophoblast cells and for vascular remodeling during placentation. In cancer cells, autophagy has a dual role, as it has been shown both as tumor promoter and inhibitor, depending on the stage and tumor considered. In this review, we summarized the similarities and differences between trophoblast cell invasion and cancer cell metastasis specifically evaluating the role of autophagy in both processes.

The role of autophagy in metal-induced urogenital carcinogenesis

Environmental and/or occupational exposure to metals such as Arsenic (As), Cadmium (Cd), and Chromium (Cr) have been shown to induce carcinogenesis in various organs, including the urogenital system. However, the mechanisms responsible for metal-induced carcinogenesis remain elusive. We and others have shown that metals are potent inducers of autophagy, which has been suggested to be an adaptive stress response to allow metal-exposed cells to survive in hostile environments. Albeit few, recent experimental studies have shown that As and Cd promote tumorigenesis via autophagy and that inhibition of autophagic signaling suppressed metal-induced carcinogenesis. In light of the newly emerging role of autophagic involvement in metal-induced carcinogenesis, the present review focuses explicitly on the mechanistic role of autophagy and potential signaling pathways involved in As-, Cd-, and Cr-induced urogenital carcinogenesis.

Regulation of tamoxifen sensitivity by the PLAC8/MAPK pathway axis is antagonized by curcumin-induced protein stability change

Tamoxifen resistance remains the major obstacle to the estrogen receptor positive breast cancer endocrine therapy. Placenta-specific 8 (PLAC8) has been implicated in epithelial-mesenchymal transition and tumorigenesis. However, the molecular mechanisms underlying PLAC8 function in the context of tamoxifen resistance are unclear. Curcumin has attracted considerable attention in the last decades. It is isolated from Curcuma longa and has beneficial effects in cancer therapy. We studied this property by using MCF-7 and tamoxifen-resistant breast cancer cells (MCF-7/TAM) cell lines. PLAC8 can regulate MCF-7/TAM cell drug sensitivity through the MAPK/ERK pathway and shows the potential effects of curcumin or as a possible druggable target against tamoxifen failure.

Programmed cell death (PCD) control in plants: New insights from the Arabidopsis thaliana deathosome

Programmed cell death (PCD) is a genetically controlled process that leads to cell suicide in both eukaryotic and prokaryotic organisms. In plants PCD occurs during development, defence response and when exposed to adverse conditions. PCD acts controlling the number of cells by eliminating damaged, old, or unnecessary cells to maintain cellular homeostasis. Unlike in animals, the knowledge about PCD in plants is limited. The molecular network that controls plant PCD is poorly understood. Here we present a review of the current mechanisms involved with the genetic control of PCD in plants. We also present an updated version of the AtLSD1 deathosome, which was previously proposed as a network controlling HR-mediated cell death in Arabidopsis thaliana. Finally, we discuss the unclear points and open questions related to the AtLSD1 deathosome.

Placenta-specific 8 limits IFNγ production by CD4 T cells in vitro and promotes establishment of influenza-specific CD8 T cells in vivo

During type 1 immune responses, CD4 T helper 1 (Th1) cells and CD8 T cells are activated via IL-12 and contribute to the elimination of intracellular pathogens through interferon gamma (IFNγ) production. In this study, we identified Placenta-specific 8 (Plac8) as a gene that is uniquely expressed in Th1 CD4 T cells relative to other CD4 T cell subsets and hypothesized that Plac8 may represent a novel therapeutic target in Th1 CD4 T cells. First, we determined that Plac8 mRNA in CD4 T cells was induced following IL-12 stimulation via an indirect route that required new protein synthesis. Upon evaluating the functional relevance of Plac8 expression in Th1 CD4 T cells, we discovered that Plac8 was important for suppressing IFNγ mRNA and protein production by CD4 T cells 24 hours after IL-12 stimulation, however Plac8 did not contribute to pathogenic CD4 T cell function during two models of intestinal inflammation. We also noted relatively high basal expression of Plac8 in CD8 T cells which could be further induced following IL-12 stimulation in CD8 T cells. Furthermore, Plac8 expression was important for establishing an optimal CD8 T cell response against influenza A virus via a T cell-intrinsic manner. Altogether, these results implicate Plac8 as a potential regulator of Th1 CD4 and CD8 T cell responses during Th1 T cell-driven inflammation.

Plac8-mediated autophagy regulates nasopharyngeal carcinoma cell function via AKT/mTOR pathway

To explore the relationship between autophagy and cell function, we investigated how PLAC8‐mediated autophagy influences proliferation, apoptosis and epithelial‐mesenchymal transition (EMT) in NPC. Colony formation analyses and CCK8 assays were used to assess the proliferative capacity of NPC cells. Transmission electron microscopy (TEM) was used to identify autophagosomes. Autophagic flux was monitored using the tandem monomeric RFP‐GFP‐tagged LC3 (tfLC3) assay. The rate of apoptosis in NPC cells was analysed by flow cytometry. Western blot analysis was used to evaluate the activation of autophagy and the signalling status of the AKT/mTOR pathway. Our study reveals that knocking out PLAC8 (koPLAC8) induces autophagy and apoptosis, while suppressing NPC cell proliferation and EMT. However, inhibition of autophagy with 3‐methyladenine or by knocking down Beclin‐1 reverses the cell proliferation, apoptosis and EMT influenced by koPLAC8. We find that koPLAC8 inhibits the phosphorylation of AKT and its downstream target, mTOR. Moreover, immunofluorescence and co‐immunoprecipitation reveal complete PLAC8/AKT colocalization and PLAC8/AKT interaction, respectively. Furthermore, knockout of PLAC8 induced autophagy and inactivated AKT/mTOR signalling pathway of NPC xenografts. Overall, our findings demonstrate that koPLAC8 induces autophagy via the AKT/mTOR pathway, thereby inhibiting cell proliferation and EMT, and promoting apoptosis in NPC cells.

PGRMC1 phosphorylation affects cell shape, motility, glycolysis, mitochondrial form and function, and tumor growth

BACKGROUND

Progesterone Receptor Membrane Component 1 (PGRMC1) is expressed in many cancer cells, where it is associated with detrimental patient outcomes. It contains phosphorylated tyrosines which evolutionarily preceded deuterostome gastrulation and tissue differentiation mechanisms.

RESULTS

We demonstrate that manipulating PGRMC1 phosphorylation status in MIA PaCa-2 (MP) cells imposes broad pleiotropic effects. Relative to parental cells over-expressing hemagglutinin-tagged wild-type (WT) PGRMC1-HA, cells expressing a PGRMC1-HA-S57A/S181A double mutant (DM) exhibited reduced levels of proteins involved in energy metabolism and mitochondrial function, and altered glucose metabolism suggesting modulation of the Warburg effect. This was associated with increased PI3K/AKT activity, altered cell shape, actin cytoskeleton, motility, and mitochondrial properties. An S57A/Y180F/S181A triple mutant (TM) indicated the involvement of Y180 in PI3K/AKT activation. Mutation of Y180F strongly attenuated subcutaneous xenograft tumor growth in NOD-SCID gamma mice. Elsewhere we demonstrate altered metabolism, mutation incidence, and epigenetic status in these cells.

CONCLUSIONS

Altogether, these results indicate that mutational manipulation of PGRMC1 phosphorylation status exerts broad pleiotropic effects relevant to cancer and other cell biology.

Placenta-Specific 8 Is Overexpressed and Regulates Cell Proliferation in Low-Grade Human Pancreatic Neuroendocrine Tumors

BACKGROUND/AIMS

Many aspects of the biology of pancreatic neuroendocrine tumors (PanNETs), including determinants of proliferative, invasive, and metastatic potential, remain poorly understood. Placenta-specific 8 (PLAC8), a gene with unknown molecular function, has been reported to have tumor-promoting roles in different human malignancies, including exocrine pancreatic cancer. Since preliminary data suggested deregulation of PLAC8 expression in PanNET, we have performed detailed analyses of PLAC8 expression and function in human PanNET.

METHODS

Primary tissue from PanNET patients was immunohistochemically stained for PLAC8, and expression was correlated with clinicopathological data. In vitro, PLAC8 expression was inhibited by siRNA transfection in PanNET cell lines and effects were analyzed by qRT-PCR, Western blot, and proliferation assays.

RESULTS

We report that PLAC8 is expressed in the majority of well-differentiated human PanNETs, predominantly in early-stage and low-grade tumors. SiRNA-mediated knockdown of PLAC8 in PanNET cells resulted in decreased proliferation and viability, while apoptosis was not induced. Mechanistically, these effects were mediated by attenuation of cell cycle progression, as Western blot analyses demonstrated upregulation of the tumor suppressor p21/CDKN2A and downregulation of the cell cycle regulator Cyclin D1 as well as reduced levels of phosphorylated ribosomal protein s6 and retinoblastoma protein.

CONCLUSION

Our findings establish PLAC8 as a central mediator of cell growth in a subset of human PanNET, providing evidence for the existence of distinct molecular subtypes within this class of tumors.

Knockout of the Placenta Specific 8 Gene Affects the Proliferation and Migration of Human Embryonic Kidney 293T Cell

Candidate oncogene placenta specific 8 (PLAC8) has been identified to participate in different cellular process and human diseases. However, the effects of PLAC8 on cell proliferation and migration in human kidney cancer (KC) remained unclear. In current study, physiological effects of PLAC8 in immortalized human embryonic kidney cell line (HEK293T) were investigated in vitro. Two PLAC8 knockout (KO) cell lines were established via CRISPR/Cas9-mediated methods combined with fluorescence activated single cell sorting. To classify the characteristic of PLAC8 during cell proliferation and migration in HEK293T, cellular proliferative activity was analyzed by cell counting and colony formation assay. Cell cycle distribution was analyzed by flow cytometry. Cellular motile activity was analyzed by wound-healing and migration assay. Further underlying molecular mechanism was explored via western blot. With the KO cell lines, it was found that PLAC8 KO could decrease cell proliferation. Moreover, the inhibitory effects of PLAC8 KO on cell proliferation were associated with a G2/M arrest in cell cycle progression concomitant with a remarkable inhibition of Cyclin B1 and elevation of Cyclin A. The alteration of cell cycle proteins and E-cadherin might further associate with the enhancement of cell motility. Our study revealed a novel role for PLAC8 in cell proliferation and migration of HEK293T cells, which might shed light on further study of PLAC8 on human KC.

Placenta-specific protein 8 promotes the proliferation of lung adenocarcinoma PC-9 cells and their tolerance to an epidermal growth factor receptor tyrosine kinase inhibitor by activating the ERK signaling pathway

Placenta-specific protein 8 (PLAC8) is a conserved protein with a molecular weight of 12.5 kDa. The specific function of this protein has not been fully elucidated, however, PLAC8 has been found to play an important tumor regulatory role in certain types of cancer, including colon, pancreatic and liver cancer. PLAC8 also participates in the regulation of the cell cycle, autophagy, epithelial-mesenchymal transition and other cellular functions, indicating its potential as a molecular target worth further investigation. The present study investigated the effect of PLAC8 on the proliferation of lung adenocarcinoma PC-9 cells and their sensitivity to gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). It was found that the inhibition of PLAC8 expression in PC-9 cells resulted in significantly decreased proliferation, whereas overexpression of PLAC8 significantly increased the proliferation (P<0.05) of PC-9 cells. Furthermore, inhibition of PLAC8 expression resulted in decreased activity of the ERK signaling pathway, while PLAC8 overexpression increased activity of this pathway. Inhibition of the ERK signaling pathway with U0126 reversed the effects induced by inhibiting or overexpressing PLAC8 on cell proliferation. In addition, overexpression of PLAC8 significantly decreased the sensitivity of PC-9 cells to gefitinib, and this effect was reversed by U0126. Overall, these results suggest that PLAC8 is involved in the regulation of proliferation of lung adenocarcinoma PC-9 cells and impacts their sensitivity to an EGFR-TKI. Thus, PLAC8 is a potential novel target in lung adenocarcinoma for future studies.

PLCA8 suppresses breast cancer apoptosis by activating the PI3k/AKT/NF-κB pathway

The cysteine‐rich lysosomal protein placenta‐specific 8 (PLAC8), also called onzin, has been shown to be involved in many types of cancers, and its role is highly dependent on cellular and physiological contexts. However, the precise function of PLAC8 in breast cancer (BC) progression remains unclear. In this study, we investigated both the clinical significance and biological functions of PLAC8 in BC progression. First, high PLAC8 expression was observed in primary BC tissues compared with adjacent normal tissues through immunohistochemistry analysis. The results of in vitro and in vivo assays further confirmed that PLAC8 overexpression promotes cell proliferation and suppress BC cell apoptosis, whereas PLAC8 silencing has the opposite effect. In addition, the forced expression of PLAC8 greatly induces cell migration, partially by affecting the EMT‐related genes, including down‐regulating E‐cadherin expression and facilitating vimentin expression. Further mechanistic analysis confirmed that PLAC8 contributes to cell proliferation and suppresses cell apoptosis in BC by activating the PI3K/AKT/NF‐κB pathway. The results of our study provide new insights into an oncogenic role of PLAC8 and reveal a novel PLAC8/ PI3K/AKT/NF‐κB pathway as a potential therapeutic target for BC.

PLAC8 overexpression correlates with PD-L1 upregulation and acquired resistance to chemotherapies in gallbladder carcinoma

Gallbladder carcinoma (GBC) is always diagnosed at an advanced stage, and patients often miss the opportunity for surgery. Gemcitabine (GEM) and platinum-based drugs, including oxaliplatin (OXA), are mainstays of chemotherapy. However, drug resistance causes treatment failure. Hence, salvage mechanisms are critical to improve outcomes. This study revealed the positive correlation between placenta-specific protein 8 (PLAC8) overexpression and PD-L1 overexpression in GBC. Given the roles of PLAC8 and PD-L1 in chemotherapy resistance, GEM-resistant and OXA-resistant cell lines (SGC966GR and SGC966OR, respectively) were established to test whether and how PLAC8 and PD-L1 function in chemotherapy resistance. Drug-insensitive SGC966GR and SGC966OR cells upregulated MRP and MDR1 and had high expression of PLAC8. PLAC8 blockade using siRNA reversed chemotherapy resistance and downregulated MRP and MDR1 in SGC966GR and SGC966OR cells, suggesting that PLAC8 mediates chemotherapy resistance in GBC. Consistent with the increased mRNA levels of PD-L1 after the acquisition of resistance, PLAC8 knockdown reduced PD-L1 mRNA expression in SGC966GR and SGC966OR cells. In conclusion, PLAC8 overexpression in GBC patients positively correlated with PD-L1 expression. PLAC8 conferred resistance to GEM and OXA by upregulating PD-L1 expression, and PLAC8 or PD-L1 blockade may have potential for overcoming chemotherapy resistance, providing therapeutic options for chemotherapy-refractory GBC patients.

Placenta-specific 8 is a potential novel target for osimertinib resistance in non-small cell lung cancer

Currently, osimertinib (AZD9291) is the only third-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor approved by the Food and Drug Administration for the treatment of non-small cell lung cancer (NSCLC) with EGFR T790M mutations. However, acquired resistance is an inevitable clinical challenge. Although placenta-specific 8 (PLAC8) has been proven to serve an important role in tumor progression and resistance, its effect in AZD9291 resistance in NSCLC remains largely unknown. The aim of the present study was to investigate the functional role of PLAC8 in AZD9291 resistance in NSCLC. The results revealed that the level of PLAC8 was significantly upregulated in AZD9291-resistant cells compared with that in parent cells. Overexpression of PLAC8 in parent cells markedly decreased drug sensitivity, and enhanced cell proliferation, colony formation and migration. Furthermore, the levels of aldehyde dehydrogenase 1 family member A1 (ALDH1A1) were observed to be upregulated in resistant cells and PLAC8-overexpressing parent cells, suggesting that ALDH1A1 may be involved in the association between the overexpression of PLAC8 and AZD9291 resistance in NSCLC. Overall, PLAC8 overexpression promoted NSCLC resistance to AZD9291, and PLAC8 may be a potential target for the reversal of AZD9291 resistance.

Yeast expression of mammalian Onzin and fungal FCR1 suggests ancestral functions of PLAC8 proteins in mitochondrial metabolism and DNA repair

The cysteine-rich PLAC8 domain of unknown function occurs in proteins found in most Eukaryotes. PLAC8-proteins play important yet diverse roles in different organisms, such as control of cell proliferation in animals and plants or heavy metal resistance in plants and fungi. Mammalian Onzin can be either pro-proliferative or pro-apoptotic, depending on the cell type, whereas fungal FCR1 confers cadmium tolerance. Despite their different role in different organisms, we hypothesized common ancestral functions linked to the PLAC8 domain. To address this hypothesis, and to investigate the molecular function of the PLAC8 domain, murine Onzin and fungal FCR1 were expressed in the PLAC8-free yeast Saccharomyces cerevisiae. The two PLAC8-proteins localized in the nucleus and induced almost identical phenotypes and transcriptional changes when exposed to cadmium stress. Like FCR1, Onzin also reduced DNA damage and increased cadmium tolerance by a DUN1-dependent pathway. Both proteins activated transcription of ancient mitochondrial pathways such as leucine and Fe-S cluster biosynthesis, known to regulate cell proliferation and DNA repair in yeast. These results strongly suggest a common ancestral function of PLAC8 proteins and open new perspectives to understand the role of the PLAC8 domain in the cellular biology of Eukaryotes.

High Precision RPPA: Concept, Features, and Application Performance of the Integrated Zeptosens Platform

An integrated reverse phase protein array (RPPA) platform shall allow the precise monitoring of expression level and changes of proteins and their functional states in a highly parallel manner even when samples exhibit a complex matrix like in tumor tissues and are available only in very limited amounts. Ideally the full workflow from sample preparation to data visualization shall be covered.This book chapter describes the key elements of the integrated Zeptosens RPPA platform. It addresses critical platform and process design requirements, considerations, and elements as well as critical process steps and quality aspects. Sophisticated instrumentation, high sensitivity readout, and dedicated chip and assay handling equipment act in concert with streamlined protocols, optimal reagents, and dedicated lab equipment in the hands of trained users to achieve an outstanding overall performance of the realized system. Based on results from comprehensive signaling protein and pathway profiling studies targeted for preclinical drug efficacy testing and development, it gives an overview of application performance by means of coefficients of variation (CVs) that can be achieved for assay signals from technical and biological sample replicates with this state-of-the-art integrated RPPA platform and process.The Zeptosens RPPA platform has proven to provide valuable biological information with a high level of confidence and has shown its validity in generating sound mechanistic as well as prognostic and predictive information when analyzing cell and tissue materials on the functional protein level.

CRISPR/Cas9-mediated generation of a Plac8 knockout mouse model

Placenta specific 8 (PLAC8, also known as ONZIN) is a multi-functional protein that is highly expressed in the intestine, lung, spleen, and innate immune cells, and is involved in various diseases, including cancers, obesity, and innate immune deficiency. Here, we generated a Plac8 knockout mouse using the CRISPR/Cas9 system. The Cas9 mRNA and two single guide RNAs targeting a region near the translation start codon at Plac8 exon 2 were microinjected into mouse zygotes. This successfully eliminated the conventional translation start site, as confirmed by Sanger sequencing and PCR genotyping analysis. Unlike the previous Plac8 deficient models displaying increased adipose tissue and body weights, our male Plac8 knockout mice showed rather lower body weight than sex-matched littermate controls, though the only difference between these two mouse models is genetic context. Differently from the previously constructed embryonic stem cell-derived Plac8 knockout mouse that contains a neomycin resistance cassette, this knockout mouse model is free from a negative selection marker or other external insertions, which will be useful in future studies aimed at elucidating the multi-functional and physiological roles of PLAC8 in various diseases, without interference from exogenous foreign DNA.

Revising the PLAC8 gene family: from a central role in differentiation, proliferation, and apoptosis in mammals to a multifunctional role in plants

PLAC8 is a cysteine-rich protein described as a central mediator of tumor evolution in mammals; as such, it represents a promising candidate for diagnostic and therapeutic targeting. The human PLAC8 gene is also involved in contact hypersensitivity response and presents a role in psoriatic skin. In plants, PLAC8 motif-containing proteins are involved in the determination of organ size and growth, response to infection, Ca2+ influx, Cd resistance, and zinc detoxification. In general, PLAC8 motif-containing proteins present the conserved CCXXXXCPC or CLXXXXCPC region. However, there is no devised nomenclature for the PLAC8 motif-containing proteins. Here, through the analysis of 445 sequences, we show that PLAC8 motif-containing proteins constitute a unique gene family, and we propose a unified nomenclature. This is the first report indicating the existence of different groups of PLAC8 proteins, which we have called types I, II, and III. Type I genes are found in mammals, fungi, plants, and algae, and types II and III are exclusive to plants. Our study describes for the first time PLAC8 type III proteins. Whether these sequences maintain their known functional role or possess distinct functions of types I and II genes remains unclear.

Placenta specific 8 gene induces epithelial-mesenchymal transition of nasopharyngeal carcinoma cells via the TGF-β/Smad pathway

The present study aimed to investigate the effects and mechanisms of PLAC8 on the epithelial-mesenchymal transition (EMT) of Nasopharyngeal carcinoma (NPC). The expression of PLAC8 in NPC and nasopharyngitis (NPG) tissues from 150 patients was determined using immunohistochemistry. The levels of PLAC8 in five NPC cell lines and nasopharyngeal permanent epithelial cell line were measured using western blotting. We then knocked out or overexpressed PLAC8 in CNE2 cells. Cell proliferation, wound healing, migration, and invasion assays were used to analyze the effects of PLAC8 on the proliferation, migration, and invasion in vivo and vitro. The results showed that the expression of PLAC8 was much higher in NPC tissues than in NPG tissues. The expression of PLAC8 was higher in all the cell lines than in the nasopharyngeal permanent epithelial cells. PLAC8 knockout resulted in significant decreases in cell proliferation, migration, and invasion; associated with lower protein levels of N-cadherin; and increased levels of E-cadherin. Overexpression of PLAC8 had the opposite effect. Furthermore, knockout of PLAC8 inactivated TGF-β/SMAD signaling pathway and suppressed the growth of NPC xenografts. PLAC8 may promote the carcinogenesis and EMT of NPC via the TGF-β/Smad pathway, which suggests that PLAC8 may be a potential biomarker for NPC.

Co-expression Network Analysis of Biomarkers for Adrenocortical Carcinoma

Adrenocortical carcinoma (ACC) is a rare malignancy with a poor prognosis. And currently, there are no specific diagnostic biomarkers for ACC. In our study, we aimed to screen biomarkers for disease diagnosis, progression and prognosis. We firstly used the microarray data from public database Gene Expression Omnibus database to construct a weighted gene co-expression network, and then to identify gene modules associated with clinical features of ACC. Though this algorithm, a significant module with R² = 0.64 (P = 9 × 10^-5) was identified. Co-expression network and protein–protein interaction network were performed for screen the candidate hub genes. Checked by The Cancer Genome Atlas (TCGA) database, another independent dataset GSE19750, and GEPIA database, using one-way ANOVA, Pearson’s correlation, survival analysis, diagnostic capacity (ROC curve) and expression level revalidation, a total 12 real hub genes were identified. Gene ontology and KEGG pathway analysis of genes in the significant module revealed that the hub genes are significantly enriched in cell cycle regulation. Moreover, gene set enrichment analysis suggests that the samples with highly expressed hub genes are correlated with cell cycle. Taken together, our integrated analysis has identified 12 hub genes that are associated with the progression and prognosis of ACC; these hub genes might lead to poor outcomes by regulating the cell cycle.

The novel KLF4/PLAC8 signaling pathway regulates lung cancer growth

Accumulating evidence suggests that placenta-specific 8 (PLAC8) plays an important role in normal cellular process and human diseases, including multiple types of human tumors, and its role is highly relied upon in cellular and physiologic contexts. However, there are no reports on its expression profile and biological roles during lung cancer development. In the current study, both the clinical implications and biological effects of PLAC8 in lung cancer (LC) progression were investigated, and we identified and described the novel Krüppel-like factor 4 (KLF4)/PLAC8 regulatory pathway in cancer progression. Elevated PLAC8 levels were positively correlated with tumor size, histological grade, and tumor node metasis (TNM) stage, and LC patients with high PLAC8 expression suffered poor outcomes. In vitro and in vivo assays further revealed that endogenous PLAC8 promoted cell proliferation and tumor formation. We also found downregulated PLAC8 protein in several LC cell lines following the induction of KLF4, and immunohistochemistry analysis of LC tissues by microarray indicated a potential inverse correlation between PLAC8 and KLF4 expression. Luciferase reporter analysis and chromatin immunoprecipitation assays determined that KLF4 negatively regulated PLAC8 promoter activity via directly binding to the promoter region. Furthermore, the growth inhibition resulting from KLF4 overexpression was partially rescued by ectopic PLAC8 expression. Together, our data uncovered a previously unidentified role of PLAC8 as a central mediator in LC progression. PLAC8 was transcriptionally repressed by KLF4, and the novel KLF4/PLAC8 axis may act as a promising candidate target for LC diagnosis and therapy.

Radiation resistance of the lung adenocarcinoma is related to the AKT-Onzin-POU5F1 axis

Non-small cell lung carcinoma is the predominant type of lung cancer, and shows an easily developable tolerance to radiotherapy. Cancer stem cells are suggested to be involved in the resistance against therapies. Onzin might be accumulated during the process tumor overcoming the radiation stress. To address the relationship between Onzin, stemness and radiation resistance, we treated the lung cancer tumor bearing mice with radiaotherapy and observed the differences between radiation sensitive (RS) and resistant (RR) tumors. Immunohistochemistry and HE staining were used to observe Onzin and POU5F1 expression in tumor tissues. Quantitative realtime-PCR and Western blot were applied for Onzin and POU5F1 in tumors and cells. In-vitro cellular viability was assessed by CCK8 methods for tumor derived cells. The stably transfected A549 cell lines overexpressing Onzin were generated through lentivirus transfection. After radiotherapy, those RR adenocarcinoma tumors and cells derived from them showed an increased Onzin expression. Further, RR cells were found upregulated stemness, indicated by increased sphericity and proliferation, as well as POU5F1 expression. Next, we overexpressed Onzin in the A549 cells and found an elevated POU5F1 expression, increased proliferation, and enhanced sphericity. Moreover, this could be suppressed by the AKT inhibitor MK-2260. In vivo, the A549 cells overexpressing Onzin showed not only higher tumor formation capability and growth, but also a significant resistance to radiation. Taken together, RR tumors have upregulated Onzin and POU5F1 expression. Ectopic expression of Onzin promotes the POU5F1 expression as well as stemness functions, and confers adenocarcinomas the resistance to radiotherapy.

Role of BCL9L in transforming growth factor-β (TGF-β)-induced epithelial-to-mesenchymal-transition (EMT) and metastasis of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) has a low overall survival rate, which is approximately 20% during the first year and decreases to less than 6% within five years of the disease. This is due to premature dissemination accompanied by a lack of disease-specific symptoms during the initial stages. Additionally, to date there are no biomarkers for an early prognosis available.A growing number of studies indicate that epithelial to mesenchymal transition (EMT), triggered by WNT-, TGF-β- and other signaling pathways is crucial for the initiation of the metastatic process in PDAC. Here we show, that BCL9L is up-regulated in PDAC cell lines and patient tissue compared to non-cancer controls. RNAi-induced BCL9L knockdown negatively affected proliferation, migration and invasion of pancreatic cancer cells. On a molecular basis, BCL9L depletion provoked an increment of E-cadherin protein levels, with concomitant increase of β-catenin retention at the plasma membrane. This is linked to the induction of a strong epithelial phenotype in pancreatic cancer cells upon BCL9L knockdown even in the presence of the EMT-inducer TGF-β. Finally, xenograft mouse models of pancreatic cancer revealed a highly significant reduction in the number of liver metastases upon BCL9L knockdown. Taken together, our findings underline the key importance of BCL9L for EMT and thus progression and metastasis of pancreatic cancer cells. Direct targeting of this protein might be a valuable approach to effectively antagonize invasion and metastasis of PDAC.

Induction of Plac8 promotes pro-survival function of autophagy in cadmium-induced prostate carcinogenesis

Chronic exposure to cadmium is known to be a risk factor for human prostate cancer. Despite over-whelming evidence of cadmium causing carcinogenicity in humans, the specific underlying molecular mechanisms that govern metal-induced cellular transformation remain unclear. Acute exposure (up to 72 h) to cadmium induces apoptosis in normal prostate epithelial cells (RWPE-1), while chronic exposure (>1 year) transforms these cells to a malignant phenotype (cadmium-transformed prostate epithelial cells; CTPE). Increased expression of autophagy-regulated genes; Plac8, LC3B and Lamp-1; in CTPE cells was associated with cadmium-induced transformation. Increased expression of Plac8, a regulator of autophagosome/autolysosome fusion, facilitates the pro-survival function of autophagy and upregulation of pAKT^(ser473) and NF-κβ, to allow CTPE to proliferate. Likewise, inhibition of Plac8 suppresses CTPE cell growth. Additionally, overexpression of Plac8 in RWPE-1 cells induces resistance to cadmium toxicity. Pharmacological inhibitors and an inducer of autophagy failed to affect Plac8 expression and CTPE cell viability, suggesting a unique role for Plac8 in cadmium-induced prostate epithelial cell transformation. These results support a role for Plac8 as an essential component in the cadmium-induced transformation of normal prostate epithelial cells to a cancerous state.

The deubiquitinating enzyme USP5 promotes pancreatic cancer via modulating cell cycle regulators

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal solid tumors. With an overall five-year survival rate remaining below 6%, there is an explicit need to search for new molecular targets for therapeutic interventions. We undertook a barcode labelled short-hairpin (shRNA) library screen in pancreatic cancer cells in order to identify novel genes promoting cancer survival and progression. Among the candidate genes identified in this screen was the deubiquitinase USP5, which subsequent gene expression analyses demonstrated to be significantly upregulated in primary human pancreatic cancer tissues. Using different knockdown approaches, we show that expression of USP5 is essential for the proliferation and survival of pancreatic cancer cells, tested under different 2D and 3D cell culture conditions as well as in in vivo experiments. These growth inhibition effects upon knockdown of USP5 are mediated primarily by the attenuation of G1/S phase transition in the cells, which is accompanied by accumulation of DNA damage, upregulation of p27, and increased apoptosis rates. Since USP5 is overexpressed in cancer tissues, it can thus potentially serve as a new target for therapeutic interventions, especially given the fact that deubiquitinases are currently emerging as new class of attractive drug targets in cancer.

Progesterone receptor membrane component 1 is phosphorylated upon progestin treatment in breast cancer cells

Menopausal hormone therapy, using estrogen and synthetic progestins, is associated with an increased risk of developing breast cancer. The effect of progestins on breast cells is complex and not yet fully understood. In previous in vitro and in vivo studies, we found different progestins to increase the proliferation of Progesterone Receptor Membrane Component-1 (PGRMC1)-overexpressing MCF7 cells (MCF7/PGRMC1), suggesting a possible role of PGRMC1 in transducing membrane-initiated progestin signals.

Understanding the activation mechanism of PGRMC1 by progestins will provide deeper insights into the mode of action of progestins on breast cells and the often-reported phenomenon of elevated breast cancer rates upon progestin-based hormone therapy. In the present study, we aimed to further investigate the effect of progestins on receptor activation in MCF7 and T47D breast cancer cell lines. We report that treatment of both breast cancer cell lines with the progestin norethisterone (NET) induces phosphorylation of PGRMC1 at the Casein Kinase 2 (CK2) phosphorylation site Ser181, which can be decreased by treatment with CK2 inhibitor quinalizarin. Point mutation of the Ser181 phosphorylation site in MCF7/PGRMC1 cells impaired proliferation upon NET treatment. This study gives further insights into the mechanism of differential phosphorylation of the receptor and confirms our earlier hypothesis that phosphorylation of the CK2-binding site is essential for activation of PGRMC1. It further suggests an important role of PGRMC1 in the tumorigenesis and progression of breast cancer in progestin-based hormone replacement therapy.

Inhibition of autophagy prevents cadmium-induced prostate carcinogenesis

BACKGROUND

Cadmium, an established carcinogen, is a risk factor for prostate cancer. Induction of autophagy is a prerequisite for cadmium-induced transformation and metastasis. The ability of Psoralidin (Pso), a non-toxic, orally bioavailable compound to inhibit cadmium-induced autophagy to prevent prostate cancer was investigated.

METHODS

Psoralidin was studied using cadmium-transformed prostate epithelial cells (CTPE), which exhibit high proliferative, invasive and colony forming abilities. Gene and protein expression were evaluated by qPCR, western blot, immunohistochemistry and immunofluorescence. Xenograft models were used to study the chemopreventive effects in vivo.

RESULTS

Cadmium-transformed prostate epithelial cells were treated with Pso resulting in growth inhibition, without causing toxicity to normal prostate epithelial cells (RWPE-1). Psoralidin-treatment of CTPE cells inhibited the expression of Placenta Specific 8, a lysosomal protein essential for autophagosome and autolysosome fusion, which resulted in growth inhibition. Additionally, Pso treatment caused decreased expression of pro-survival signalling proteins, NFκB and Bcl2, and increased expression of apoptotic genes. In vivo, Pso effectively suppressed CTPE xenografts growth, without any observable toxicity. Tumours from Pso-treated animals showed decreased autophagic morphology, mesenchymal markers expression and increased epithelial protein expression.

CONCLUSIONS

These results confirm that inhibition of autophagy by Pso plays an important role in the chemoprevention of cadmium-induced prostate carcinogenesis.

Overexpression of placenta specific 8 is associated with malignant progression and poor prognosis of clear cell renal cell carcinoma

BACKGROUND

Placenta specific 8 (PLAC8) plays an important role in many different cellular processes and human diseases, including multiple types of cancer. However, the functional role of PLAC8 in clear cell renal cell carcinoma (ccRCC) has never been elucidated.

METHODS

PLAC8 mRNA expression was investigated in 31 pairs of fresh ccRCC tumor tissues and matched adjacent non-tumor tissues by RT-qPCR and confirmed by analyzing the TCGA KRCC dataset which contains RNA-seq data of 534 ccRCC and 72 solid normal tissues. Protein level of PLAC8 expression was also investigated using immunohistochemistry in 129 ccRCC samples. Correlations with clinicopathological factors and overall survival were analyzed. To examine its effect on the biological activity, PLAC8 siRNAs were transfected into ccRCC cells. Cell proliferation was assessed by CCK8 cell viability assays, clone formation assays, and EdU incorporation assays. Cell invasion was examined using transwell assays. RNA sequencing was then performed to further elucidate the mechanisms by which PLAC8 regulates the cancer.

RESULTS

PLAC8 expression was positively correlated with tumor size, metastasis, and clinical stage of ccRCC. Additionally, high PLAC8 expression was closely associated with a shorter overall survival time. Knockdown of PLAC8 with siRNAs significantly reduced the proliferation and invasion of RCC cells and increased the sensitivity of RCC cells to cisplatin. RNA-seq analysis revealed that knockdown of PLAC8 down-regulated the expression of a panel of inflammatory mediators, which suggested that PLAC8 is associated with the ccRCC inflammatory microenvironment. Patients with high expression of PLAC8 had a significantly higher number of infiltrative lymphocytes than patients with low expression of PLAC8.

CONCLUSION

Our findings suggest that PLAC8 may be a potential prognostic indicator and therapeutic target for ccRCC.

The Effect of Botulinum Toxin Type A on Expression Profiling of Long Noncoding RNAs in Human Dermal Fibroblasts

Objective. This study was aimed at analyzing the expressions of long noncoding RNAs (lncRNAs) in Botulinum Toxin Type A (BoNTA) treated human dermal fibroblasts (HDFs) in vitro. Methods. We used RNA sequencing to characterize the lncRNAs and mRNAs transcriptome in the control and BoNTA treated group, in conjunction with application of GO (gene ontology) analysis and KEGG (kyoto encyclopedia of genes and genomes) analysis to delineate the alterations in gene expression. We also obtained quantitative real time polymerase chain reaction (qRT-PCR) to confirm some differentially expressed genes. Results. Numerous differentially expressed genes were observed by microarrays between the two groups. qRT-PCR confirmed the changes of six lncRNAs (RP11-517C16.2-001, FR271872, LOC283352, RP11-401E9.3, FGFR3P, and XXbac-BPG16N22.5) and nine mRNAs (NOS2, C13orf15, FOS, FCN2, SPINT1, PLAC8, BIRC5, NOS2, and COL19A1). Farther studies indicated that the downregulating effect of BoNTA on the expression of FGFR3P was time-related and the dosage of BoNTA at a range from 2.5 U/10⁶ cells to 7.5 U/10⁶ cells increased the expression of FGFR3P and COL19A1 in HDFs as well. Conclusion. The expression profiling of lncRNAs was visibly changed in BoNTA treated HDFs. Further studies should focus on several lncRNAs to investigate their functions in BoNTA treated HDFs and the underlying mechanisms.

Hes1 Controls Exocrine Cell Plasticity and Restricts Development of Pancreatic Ductal Adenocarcinoma in a Mouse Model

Perturbation of pancreatic acinar cell state can lead to acinar-to-ductal metaplasia (ADM), a precursor lesion to the development of pancreatic ductal adenocarcinoma (PDAC). In the pancreas, Notch signaling is active both during development and in adult cellular differentiation processes. Hes1, a key downstream target of the Notch signaling pathway, is expressed in the centroacinar compartment of the adult pancreas as well as in both preneoplastic and malignant lesions. In this study, we used a murine genetic in vivo approach to ablate Hes1 in pancreatic progenitor cells (Ptf1a^+/Cre; Hes1^fl/fl). Using this model, we studied the role of Hes1 in both acinar cell plasticity and pancreatic regeneration after caerulein-induced pancreatitis and in Kras^G12D-driven PDAC development. We show that, although pancreatic development is not perturbed on the deletion of Hes1, terminal acinar differentiation in the adult pancreas is compromised. Moreover, the loss of Hes1 leads to the impaired regeneration of the exocrine compartment, accelerated fatty metaplasia, and persistent ADM after acute caerulein-induced pancreatitis. In Kras^G12D-driven carcinogenesis, Hes1 ablation resulted in increased ADM, decreased formation of high-grade pancreatic intraepithelial neoplasias, and accelerated development of PDAC with shortened survival time. In conclusion, Hes1 plays a key role in acinar cell integrity and plasticity on cellular insults. Furthermore, Hes1 is an essential component of the pancreatic intraepithelial neoplasias-to-PDAC route in Kras^G12D-driven mouse pancreatic carcinogenesis.