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The primary aim of this study was to evaluate the activation of the PERP and Akt oncogenes in the induction of skin cancer in FVB/N mice by a stepwise chemical process. Forty four-week-old female FVB/N mice were randomly divided into a control group (n = 8) and two experimental groups (group A: n = 16, group B: n = 16). In the study, the groups were subjected to a two-stage carcinogenesis procedure. This consisted of an initial application of 97.4 nmol DMBA to shaved skin on the back, followed by applications of 32.4 nmol TPA after thirteen weeks for group A and after twenty weeks for group B. The control group received no treatment. Skin conditions were monitored weekly for tumor development. At the end of the experiment, the animals were euthanized for further tissue sampling. Examination of the skin lesions in the experimental groups showed a correlation with tumor progression, ranging from dysplasia to carcinoma. Tumor samples were examined both histologically and immunohistochemically. Notably, and PERP expression was higher in precancerous than in malignant tumors. The differences in expression between precancerous and benign tumors provide further evidence of a role for PERP and Akt in the transition from benign to malignant states. Our findings underscore the critical roles of PERP and Akt in the pathogenesis of skin cancer and suggest their potential as biomarkers for early detection and targets for therapeutic intervention. [ABSTRACT FROM AUTHOR]

Zhongxiang Liu,1,* Shuhua Han,2,* Yuhong Luo,3,* Zhangyan Zhao,4 Lingyu Ni,5 Linlin Chai,6 Haicheng Tang4 1Department of Pulmonary and Critical Care Medicine, the Yancheng Clinical College of Xuzhou Medical University, The First People’s Hospital of Yancheng, the First Affiliated Hospital of Jiangsu Vocational College of Medicine, Yancheng, 224000, People’s Republic of China; 2Department of Respiratory and Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, 210009, People’s Republic of China; 3College of Life Science and Technology, Guangxi University, Nanning, 530004, People’s Republic of China; 4Department of Respiratory and Critical Care Medicine, Shanghai Public Health Clinical Center, Fudan University, Shanghai, 201508, People’s Republic of China; 5China School of Life Sciences, Nanjing University, Nanjing, Jiangsu, 210046, People’s Republic of China; 6Department of Pathology, The Yancheng Clinical College of Xuzhou Medical University, The First People’s Hospital of Yancheng, The First Affiliated Hospital of Jiangsu Vocational College of Medicine, Yancheng, 224000, People’s Republic of China*These authors contributed equally to this workCorrespondence: Linlin Chai, Department of Pathology, The Yancheng Clinical College of Xuzhou Medical University, The First People’s Hospital of Yancheng, Yancheng, Jiangsu, People’s Republic of China, Email chailinlin0924@163.com Haicheng Tang, Department of Respiratory and Critical Care Medicine, Shanghai Public Health Clinical Center, Fudan University, 2901, Caolang Road, Jinshan District, Shanghai, 201508, People’s Republic of China, Email thc822@163.comBackground: PERP, a member of the peripheral myelin protein gene family, is a new therapeutic target in cancer. The relationships between PERP and immune cell infiltration in lung cancer have not been studied. Therefore, the role of PERP in the tumour microenvironment (TME) of lung cancer needs to be further explored.Methods: In this study, we explored the association between PERP expression and clinical characteristics by analysing data from the TCGA database. Cox regression and Kaplan‒Meier methods were used to investigate the relationship between the expression of PERP and overall survival in patients with lung adenocarcinoma (LUAD). The relationship between PERP expression and the degree of infiltration of specific immune cell subsets in LUAD was evaluated using the TIMER database and GEPIA. We also performed GO enrichment analysis and KEGG enrichment analysis to reveal genes coexpressed with PERP using the Coexpedia database. Finally, we verified the expression and function of PERP in LUAD tissues and the A549 cell line by RT‒PCR, Western blot, CCK-8, IHC, and wound healing assays. The mouse model was used to study the in vivo effects of PERP.Results: According to our results, PERP expression was significantly higher in LUAD tissues and associated with the clinical characteristics of the disease. Survival was independently associated with PERP in LUAD patients. We further verified that PERP might regulate B-cell infiltration in LUAD to affect the prognosis of LUAD. To identify PERP-related signalling pathways in LUAD, we performed a genome-aggregation analysis (GSEA) between low and high PERP expression datasets. LUAD cells express higher levels of PERP than paracarcinoma cells, and PERP inhibits the proliferation and metastasis of A549 cells through apoptosis.Conclusion: PERP may affect the prognosis of lung adenocarcinoma by inhibiting apoptosis and is associated with immune cell infiltration.Keywords: PERP, lung adenocarcinoma, apoptosis, prognosis

Hereditary palmoplantar keratodermas (PPKs) are a clinically and genetically heterogeneous group of disorders characterized by excessive epidermal thickening of palms and soles. Several genes have been associated with PPK including PERP, a gene encoding a crucial component of desmosomes that has been associated with dominant and recessive keratoderma. We report a patient with recessive erythrokeratoderma (EK) in which whole exome sequencing (WES) prioritized by human phenotype ontology (HPO) terms revealed the presence of the novel variant c.153C > A in the N-terminal region the PERP gene. This variant is predicted to have a nonsense effect, p.(Cys51Ter), resulting in a premature stop codon. We demonstrated a marked reduction in gene expression in cultured skin fibroblasts obtained from the patient. Despite the PERP gene is expressed at low levels in fibroblasts, our finding supports a loss-of-function (LoF) mechanism for the identified variant, as previously suggested in recessive EK. Our study underscores the importance of integrating HPO analysis when using WES for molecular genetic diagnosis in a clinical setting, as it facilitates continuous updates regarding gene–clinical feature associations. [ABSTRACT FROM AUTHOR]

Evolutionarily conserved DDB1‐and CUL4‐associated factor 13 (DCAF13) is a recently discovered substrate receptor for the cullin RING‐finger ubiquitin ligase 4 (CRL4) E3 ubiquitin ligase that regulates cell cycle progression. DCAF13 is overexpressed in many cancers, although its role in breast cancer is currently elusive. In this study we demonstrate that DCAF13 is overexpressed in human breast cancer and that its overexpression closely correlates with poor prognosis, suggesting that DCAF13 may serve as a diagnostic marker and therapeutic target. We knocked down DCAF13 in breast cancer cell lines using CRISPR/Cas9 and found that DCAF13 deletion markedly reduced breast cancer cell proliferation, clone formation, and migration both in vitro and in vivo. In addition, DCAF13 deletion promoted breast cancer cell apoptosis and senescence, and induced cell cycle arrest in the G1/S phase. Genome‐wide RNAseq analysis and western blotting revealed that loss of DCAF13 resulted in both mRNA and protein accumulation of p53 apoptosis effector related to PMP22 (PERP). Knockdown of PERP partially reversed the hampered cell proliferation induced by DCAF13 knockdown. Co‐immunoprecipitation assays revealed that DCAF13 and DNA damage‐binding protein 1 (DDB1) directly interact with PERP. Overexpression of DDB1 significantly increased PERP polyubiquitination, suggesting that CRL4DCAF13 E3 ligase targets PERP for ubiquitination and proteasomal degradation. In conclusion, DCAF13 and the downstream effector PERP occupy key roles in breast cancer proliferation and potentially serve as prognostics and therapeutic targets. [ABSTRACT FROM AUTHOR]

Background: Germline autosomal dominant and autosomal recessive mutations in PERP, encoding p53 effector related to PMP‐22 (PERP), a component of epidermal desmosomes, have been associated with a spectrum of keratodermas. Monoallelic nonsense mutations cause Olmsted syndrome with severe periorificial keratoderma and palmoplantar keratoderma (PPK). Biallelic recessive frameshift and missense mutations are associated with milder forms of the disease, including generalised erythrokeratoderma and PPK. Objectives: To add new insights into the genotype‐phenotype correlations as a consequence of PERP mutations and to provide a comprehensive review of the literature. Methods: Among 26 previously unresolved families within a cohort of 180 extended Iranian families with syndromic or non‐syndromic ichthyosis, two families with shared clinical features were examined by whole‐exome sequencing and genome‐wide homozygosity mapping. Mycological and dermatopathological studies were performed to further characterise their atypical phenotypic presentations. Results: In two unrelated multiplex consanguineous families affected by ichthyosis, two novel biallelic PERP variants, NM_022121.5, c.89T > C, p.Leu30Pro and c.466G > C, p.Gly156Arg, located inside of genomic homozygosity regions of the probands were detected. Interestingly, some patients had areas of scaly psoriasiform plaques on the background of generalised ichthyosis that appeared during active cutaneous fungal infections. Mycological examinations of these lesions revealed infections caused by Candida albicans, Epidermophyton floccosum, or Trichophyton rubrum. Histopathology of the psoriasiform lesions shared some features with psoriasis, which when combined with clinical presentation, led to incorrect diagnosis of guttate psoriasis or pustular psoriasis. Conclusions: PERP variants in ichthyosis patients can confer susceptibility to recalcitrant cutaneous fungal infections. Additionally, patients with episodic psoriasiform dermatitis in the setting of keratoderma should be considered for PERP genotyping and cutaneous fungal examinations. [ABSTRACT FROM AUTHOR]

Objective. The aim of the present investigation was to study the expression of genes encoding IRS1 (insulin receptor substrate 1) and some other functionally active proteins in U87 glioma cells under silencing of polyfunctional chaperone HSPB8 for evaluation of the possible significance of this protein in intergenic interactions.

Abstract Background Pancreatic cancer is one of the most lethal human cancers. N 6-methyladenosine (m6A), a common eukaryotic mRNA modification, plays critical roles in both physiological and pathological processes. However, its role in pancreatic cancer remains elusive. Methods LC/MS was used to profile m6A levels in pancreatic cancer and normal tissues. Bioinformatics analysis, real-time PCR, immunohistochemistry, and western blotting were used to identify the role of m6A regulators in pancreatic cancer. The biological effects of methyltransferase-like 14 (METTL14), an mRNA methylase, were investigated using in vitro and in vivo models. MeRIP-Seq and RNA-Seq were used to assess the downstream targets of METTL14. Results We found that the m6A levels were elevated in approximately 70% of the pancreatic cancer samples. Furthermore, we demonstrated that METTL14 is the major enzyme that modulates m6A methylation (frequency and site of methylation). METTL14 overexpression markedly promoted pancreatic cancer cell proliferation and migration both in vitro and in vivo, via direct targeting of the downstream PERP mRNA (p53 effector related to PMP-22) in an m6A-dependent manner. Methylation of the target adenosine lead to increased PERP mRNA turnover, thus decreasing PERP (mRNA and protein) levels in pancreatic cancer cells. Conclusions Our data suggest that the upregulation of METTL14 leads to the decrease of PERP levels via m6A modification, promoting the growth and metastasis of pancreatic cancer; therefore METTL14 is a potential therapeutic target for its treatment.

Exposure to ultraviolet B (UVB) has been demonstrated to induce DNA damage as well as angiogenesis-related photo-damages, which are implicated in a variety of medical problems, including sunburn, photo-aging and skin cancers. However, the molecular mechanism related to UVB-induced photo-injuries remained fully elucidated. Here we revealed that one of the catalytic subunits of the IKK complex, IKKα, played a critical role in mediating UVB-induced apoptotic responses in two kinds of UVB sensitive cells, human keratinocyte (HaCat) and mouse embryonic fibroblasts (MEFs). This function of IKKα was unrelated to NF-κB activity, but was delivered by inducing phosphorylation and acetylation of p53 and upregulating the expression of the pro-apoptotic p53 target gene, PERP. Although IKKα kinase activity was required for mediating post-translational modifications and transactivation of 53 and PERP induction, IKKα did not show direct binding ability toward p53. Instead, IKKα could interact with CHK1, the protein kinase leading to p53 phosphorylation, and trigger CHK1 activation and CHK1/p53 complex formation. At the same time, IKKα could also interact with p300 and CBP, the acetyltransferases responsible for p53 acetylation, and trigger p300/CBP activation and p300/p53 or CBP/p53 complex formation under UVB exposure. Taken together, we have identified a novel NF-κB-independent role of IKKα in mediating UVB-induced apoptosis by regulating p53 pathway activation. Targeting IKKα/p53/PERP pathway might be helpful to prevent skin photo-damages induced by sunlight.

Lung cancer is the leading cause of cancer-related deaths worldwide. Identifying genetic risk factors and understanding their mechanisms will help reduce lung cancer incidence. The p53 apoptosis effect is related to PMP-22 (PERP), a tetraspan membrane protein, and an apoptotic effector protein downstream of p53. Although historically considered a tumor suppressor, PERP is highly expressed in lung cancers. Stable knockdown of PERP expression induces CL1-5 and A549 lung cancer cell death, but transient knockdown has no effect. Interestingly, relative to the PERP- 428GG genotype, PERP- 428CC was associated with the highest lung cancer risk (OR = 5.38; 95% CI = 2.12–13.65, p < 0.001), followed by the PERP- 428CG genotype (OR = 2.34; 95% CI = 1.55–3.55, p < 0.001). Ectopic expression of PERP-428G , but not PERP-428C , protects lung cancer cells against ROS-induced DNA damage. Mechanistically, PERP -428 SNPs differentially regulate p53 protein stability. p53 negatively regulates the expression of the antioxidant enzymes catalase (CAT) and glutathione reductase (GR), thereby modulating redox status. p53 protein stability is higher in PERP-428C -expressing cells than in PERP-428G -expressing cells because MDM2 expression is decreased and p53 Ser20 phosphorylation is enhanced in PERP-428C -expressing cells. The MDM2 mRNA level is decreased in PERP-428C -expressing cells via PTEN-mediated downregulation of the MDM2 constitutive p1 promoter. This study reveals that in individuals with PERP- 428CC, CAT/GR expression is decreased via the PTEN/MDM2/p53 pathway. These individuals have an increased lung cancer risk. Preventive antioxidants and avoidance of ROS stressors are recommended to prevent lung cancer or other ROS-related chronic diseases. [Display omitted] • ․The PERP-428CC genotype is associated with a high risk of lung cancer. • ․Cells expressing PERP-428C stabilize the p53 protein by increasing phosphor Ser20 levels and decreasing MDM2 expression. • ․In PERP-428C cells, p53 inhibits catalase and GR mRNA levels, thereby increasing intracellular ROS and cancer risk. [ABSTRACT FROM AUTHOR]

Background: PERP (p53 apoptosis effector related to PMP22) localizes to desmosomes and suppresses squamous cell carcinoma development. Loss of PERP leads to worse local control in head and neck squamous cell carcinoma (HNSCC), likely by destabilizing desmosomes. We evaluated PERP loss at HNSCC surgical margins as a predictor of local relapse. Methods: Combining discovery (n = 17) and validation (n = 31) cohorts, we examined membranous PERP protein expression by immunohistochemistry in surgical mucosal margins with competing risk analysis of the relationship between local relapse and PERP expression. Results: Of the 44 analyzable patients, the 2‐year cumulative incidence of local relapse was 44.4% for the PERP‐negative group and 16.4% for the PERP‐positive group (P =.01). A trend toward worse progression‐free survival (P =.09) and overall survival (P =.06) was observed with loss of PERP. Conclusions: PERP loss at surgical margins is associated with higher risk of local recurrence in HNSCC, warranting further evaluation in a larger prospective study. [ABSTRACT FROM AUTHOR]

• Peripheral Perp −/− memory T-cell compartment was skewed, especially CD4 + T EM cells. • The skewing of Perp −/− T EM cell compartment was a result of apoptosis resistance. • Perp −/− T EM cells were resistant to anti-Fas induced apoptosis in vitro. Under lymphopenic conditions, the rapid spontaneous proliferation produces cells that robustly differentiate into effector memory T (T EM) cells, and the aberrant expansion is preferentially driven by self-antigens. The pool size of effector memory T-cell is governed by a complex homeostatic balance between proliferation and death. Perp is a critical effector involved in the p53-dependent apoptotic pathway and widely expressed in mammalian tissues. We have previously shown that Perp has a prominent role in activation-induced cell death of peripheral Th17 cells. Here, we show that Peripheral Perp −/−CD4+ T EM cells outcompete wild type T EM cells for access to splenic niches in vivo. The skewing of the Perp −/− T EM cells compartment was not the result of a difference in lymphopenia-induced proliferation, but the resistance to apoptosis, particularly after anti-Fas treatment. Data presented in this work indicate that Perp mediates the persistence of CD4+ T EM cells in irradiation-induced lymphopenic settings. [ABSTRACT FROM AUTHOR]

Erythrokeratoderma (EK) is heterogeneous clinical entity characterized by excessive scaling with resulting erythrokeratotic plaques. Several genes have been linked to EK and they encode a number of proteins that are important for the integrity of the keratinocyte layer of the epidermis. PERP is a transcription factor that is activated by both p53 and p63. However, its deficiency in a mouse model appears to only recapitulate p63‐mediated role in skin development and organization. We report an extended multiplex consanguineous family in which an EK phenotype with a striking similarity to that observed in Perp−/− mice, is mapped to an autozygous region on chromosome 6 that spans PERP. Whole‐exome sequencing revealed a novel variant in PERP that fully segregated with the phenotype. Functional analysis of patient‐ and control‐derived keratinocytes revealed a deleterious effect of the identified variant on the intracellular localization of PERP. A previous report showed that PERP mutation causes a dominant form of keratoderma but a single patient in that report with a homozygous variant in PERP suggests that recessive inheritance is also possible. Our results, therefore, support the establishment of an autosomal recessive PERP‐related EK phenotype in humans. [ABSTRACT FROM AUTHOR]

The zoonotic pathogen Salmonella not only reduces the production performance in ducks, but also poses a serious threat to human health through eggs and pollutes water bodies through feces. SipC, an effector protein of type III secretion systems (T3SS) in Salmonella, mediates translocation of effectors into the eukaryotic host. However, the precise role of SipC effectors remains unknown in ducks. In this study, the SipC from duck granulosa cells (dGCs) was selected as bait, and the SipC-interacting proteins in Salmonella enteritidis (SE) were screened using Gal4 yeast two-hybrid system in duck. Twelve SipC-interacting proteins were identified. Among those, the p53-effector related to PMP-22 (PERP) and TGF-β activated kinase 1-binding protein 2 (TAB2) were selected to further confirm the function by GST pull-down in vitro. Over-expression of PERP resulted in not only increasing SE adhesion and invasion but also triggering the production of IL-1β and IFN-α in SE infected dGCs, while knock-down PERP showed the opposite tendency (P

Pulmonary arterial hypertension (PAH) is featured by the increase in pulmonary vascular resistance and pulmonary arterial pressure. Despite that abnormal proliferation and phenotypic changes in human pulmonary artery smooth muscle cells (HPASMCs) contributing to the pathophysiology of PAH, the underlying molecular mechanisms remain unclear. In the present study, we detected the expression of miR‐629 in hypoxia‐treated HPASMCs and explored the mechanistic role of miR‐629 in regulating HPASMC proliferation, migration and apoptosis. Hypoxia time‐dependently induced up‐regulation of miR‐629 and promoted cell viability and proliferation in HPASMCs. Treatment with miR‐629 mimics promoted HPASMCs proliferation and migration, but inhibited cell apoptosis; while knockdown of miR‐629 suppressed the cell proliferation and migration but promoted cell apoptosis in HPASMCs. The bioinformatics prediction revealed FOXO3 and PERP as downstream targets of miR‐629, and miR‐629 negatively regulated the expression of FOXO3 and PERP via targeting the 3' untranslated regions. Enforced expression of FOXO3 or PERP attenuated the miR‐629 overexpression or hypoxia‐induced enhanced effects on HPASMC proliferation and proliferation, and the suppressive effects on HPASMC apoptosis. Furthermore, the expression of miR‐629 was up‐regulated, and the expression of FOXO3 and PERP mRNA was down‐regulated in the plasma from PAH patients when compared to healthy controls. In conclusion, the present study provided evidence regarding the novel role of miR‐629 in regulating cell proliferation, migration and apoptosis of HPASMCs during hypoxia. [ABSTRACT FROM AUTHOR]

Salmonella Enteritidis (SE) can be transmitted to eggs through cecum or the ovary from infected layers and causes food poisoning in humans. The mechanism of cecal transmission has been extensively studied. However, the mechanism and route of transovarian transmission of SE remain unclear. In this study, the ducks were orally inoculated with SE, and the ovarian follicles and stroma were collected to detect SE infection. The immune responses were triggered and the innate and adaptive immune genes (TLR4, NOD1, AvβD7, and IL‐1β) were upregulated significantly during the SE challenge. Moreover, the ovary tissues (small follicle and stroma) of susceptible and resistant–laying ducks were performed by RNA sequencing. We obtained and identified 23 differentially expressed genes (DEGs) between susceptible and resistant–laying ducks in both small follicle and stroma tissues (p < 0.05). The DEGs were predominately identified in the p53 signaling pathway. The expression of key genes (p53, MDM2, PERP, caspase‐3, and Bcl‐2) involved in the signaling pathway was significantly higher in granulosa cells (dGCs) from SE‐infected ducks than those from uninfected ducks. Moreover, the overexpression of PERP resulted in further induction of p53, MDM2, caspase‐3, and Bcl‐2 during SE infection in dGCs. Whereas, an opposite trend was observed with the knockdown of PERP. Besides, it is further revealed that the PERP could enhance cell apoptosis, SE adhesion, and SE invasion in SE‐infected dGCs overexpression. Altogether, our results demonstrate the duck PERP involved in the ovarian local immune niche through p53 signaling pathway in dGCs challenged with SE. The PERP overexpression resulted in an increased induction of p53, MDM2, caspase‐3, and Bcl‐2 during SE infection in dGCs, whereas an opposite trend was observed with PERP knockdown. Duck PERP, as a negative regulator, was involved in the ovarian local immune niche through a p53 signaling pathway that promoted cell apoptosis, as well as SE adhesion and invasion during SE infection. [ABSTRACT FROM AUTHOR]

T helper 17 (Th17) cells are crucial for the pathogenesis of multiple sclerosis (MS) in humans and experimental autoimmune encephalomyelitis (EAE) in animals. High frequency of Th17 cells and low sensitivity to activation-induced cell death (AICD) are detected in MS patients. However, the mechanisms underlying apoptosis resistance of T cells remain unclear. Perp is an apoptosis-associated target of p53 and implicated in the development of cancers. Here, we show that loss of Perp in T cells does not affect Th1, Th17, or Treg cell differentiation, but does significantly increase the resistance of Perp−/− Th17 cells to AICD and anti-Fas in Lck-Cre × Perpfl/fl mice by inhibiting the caspase-dependent apoptotic pathway. Moreover, Lck-Cre × Perpfl/fl mice exhibited earlier onset of EAE and severe spinal cord inflammation and demyelination, accompanied by increased levels of pro-inflammatory cytokines and enlarged population of Th17 cells. Therefore, Perp deletion promoted Th17 responses and exacerbated the development and severity of EAE.

The genus Chamaecrista has a pantropical distribution and it is well represented in the Brazilian flora, mainly in "campos rupestres" and Riparian forests. In Brazil, 256 species are found, of which 149 are found only in Minas Gerais, corresponding more than a half of genus diversity in the country. The area selected for the study, Parque Estadual do Rio Preto (PERP), belongs to Espinhaço Range. The vegetation is composed mainly of physiognomies of cerrado and "campos rupestres", also existing areas of gallery forests and galleries. The objective of this study was to carry out the floristic and taxonomic survey of Chamaecrista at PERP, to elaborate key of identification of the species and taxonomic descriptions of the same ones. The collections were carried out within a period of two years, through unsystematic walks. The collected material was identified and deposited in the OUPR and BOTU Herbaria. 19 taxa were collected and described that comprises the Absus, Chamaecrista and Xerocalyx sections. [ABSTRACT FROM AUTHOR]

T helper 17 (Th17) cells are crucial for the pathogenesis of multiple sclerosis (MS) in humans and experimental autoimmune encephalomyelitis (EAE) in animals. High frequency of Th17 cells and low sensitivity to activation-induced cell death (AICD) are detected in MS patients. However, the mechanisms underlying apoptosis resistance of T cells remain unclear. Perp is an apoptosis-associated target of p53 and implicated in the development of cancers. Here, we show that loss of Perp in T cells does not affect Th1, Th17, or Treg cell differentiation, but does significantly increase the resistance of Perp-/- Th17 cells to AICD and anti-Fas in Lck-Cre × Perpfl/fl mice by inhibiting the caspase-dependent apoptotic pathway. Moreover, Lck-Cre × Perpfl/fl mice exhibited earlier onset of EAE and severe spinal cord inflammation and demyelination, accompanied by increased levels of pro-inflammatory cytokines and enlarged population of Th17 cells. Therefore, Perp deletion promoted Th17 responses and exacerbated the development and severity of EAE. [ABSTRACT FROM AUTHOR]

Endoplasmic reticulum stress and hypoxia are necessary components of malignant tumors growth and suppression of ERN1 (from endoplasmic reticulum to nuclei-1) signalling pathway, which is linked to the apoptosis and cell death processes, significantly decreases proliferative processes. Glioma cells with ERN1 knockdown were used in order to investigate the effect of ERN1 blockade on the expression of TP53, MDM2, PERP, and USP7 genes and its hypoxic regulation. We have studied the expression of TP53 (tumor protein 53), MDM2 (TP53 E3 ubiquitin protein ligase homolog), PERP (TP53 apoptosis effector), and USP7 (ubiquitin specific peptidase 7) genes, which are related to cell proliferation and apoptosis, in glioma cells with ERN1 knockdown under hypoxic condition. It was shown that blockade of ERN1 gene function in U87 glioma cells intensified the expression of TP53 and USP7 genes, but decreased the expression of MDM2 and PERP genes. Thus, an enhanced expression of TP53 gene in ERN1 knockdown glioma cells correlates with the decreased level of ubiquitin ligase MDM2 and increased expression level of USP7 which deubiquitinates TP53 and MDM2 and induces TP53-dependent cell growth repression and apoptosis. At the same time, the expression levels of TP53, MDM2, and USP7 genes do not change significantly in glioma cells with suppression of endoribonuclease activity only, but PERP gene expression is strongly increased. Moreover, the expression of TP53 and UPS7 genes is decreased in hypoxic conditions in control glioma cells only; however, MDM2 and PERP gene expressions are increased in both cell types, being more significant in ERN1 knockdown cells. Thus, the expression of genes encoding TP53 and related to TP53 factors depends upon the endoplasmic reticulum stress signaling as well as on hypoxia, and correlates with suppression of glioma growth under ERN1 knockdown.

MicroRNA (miRNA) deregulation is associated with various cancers. Among an expanding list of cancer-related miRNAs, deregulation of miR-125b has been well documented in many cancers including breast. Based on current knowledge, miR-125b is considered to be a tumor suppressor in breast cancers. While important messenger RNA (mRNA) targets have been defined for miR-125b, here, we aimed to further investigate direct/indirect consequences of miR-125b expression in breast cancer cells by using a transcriptome approach. Upon miR-125b expression, a total of 138 cancer-related genes were found to be differentially expressed in breast cancer cells. While only a few of these were predicted to be direct mRNA targets, majority of the gene expression changes were potentially downstream and indirect effects of miR-125b expression. Among these, activated leukocyte antigen molecule (ALCAM) mRNA and protein levels were found to be highly significantly increased upon miR-125b expression. Given the tumor suppressor role of miR-125b in our model system, upon silencing of ALCAM expression, cell proliferation rate re-increased in miR-125b-expressing cells. While ALCAM's possible context-dependent roles are not clear in breast cancer, a diverse expression pattern of ALCAM mRNA was detected in a panel of breast cancer patient samples. Differentially expressed/regulated cancer-related genes upon miR-125b expression along with the significant increase of ALCAM are of future interest to understand how deregulated expression of miR-125b may have a tumor suppressor role in breast and other cancers. [ABSTRACT FROM AUTHOR]

Protein PERP (p53 apoptosis effector related to PMP-22) is a small (21.4 kDa) transmembrane polypeptide with an amino acid sequence indicative of a tetraspanin character. It is enriched in the plasma membrane and apparently contributes to cell-cell contacts. Hitherto, it has been reported to be exclusively a component of desmosomes of some stratified epithelia. However, by using a series of newly generated mono- and polyclonal antibodies, we show that protein PERP is not only present in all kinds of stratified epithelia but also occurs in simple, columnar, complex and transitional epithelia, in various types of squamous metaplasia and epithelium-derived tumors, in diverse epithelium-derived cell cultures and in myocardial tissue. Immunofluorescence and immunoelectron microscopy allow us to localize PERP predominantly in small intradesmosomal locations and in variously sized, junction-like peri- and interdesmosomal regions ('tessellate junctions'), mostly in mosaic or amalgamated combinations with other molecules believed, to date, to be exclusive components of tight and adherens junctions. In the heart, PERP is a major component of the composite junctions of the intercalated disks connecting cardiomyocytes. Finally, protein PERP is a cobblestone-like general component of special plasma membrane regions such as the bile canaliculi of liver and subapical-to-lateral zones of diverse columnar epithelia and upper urothelial cell layers. We discuss possible organizational and architectonic functions of protein PERP and its potential value as an immunohistochemical diagnostic marker. [ABSTRACT FROM AUTHOR]

p53 apoptosis effector related to PMP-22 (PERP) is a transcriptional target gene of p53 tumour suppressor that is specifically induced during apoptosis and not during cell cycle arrest. In primary uveal melanoma (UM), the most common intraocular malignancy in adults that has a reportedly unaffected signalling pathway upstream of and including p53, PERP expression is down-regulated in the metastatic monosomy 3-type tumours, compared with the less aggressive disomy 3-type tumours. Here, we demonstrate experimentally, by the use of full-length PERP-green fluorescent protein (GFP) fusions and real-time confocal microscopy, the intracellular targeting and plasma membrane localization of PERP in living UM cells and show that expression of PERP induces caspase-mediated apoptosis in UM cells. Induction of PERP expression in GFP-PERP-transfected UM cells leads to increased levels of cleaved caspase-8 forms, as well as to reduction of its full-length substrate Bid, but not to detectable processing of caspase-9. The levels of mature caspase-8, -9 and -3 proteins significantly correlate with PERP expression levels in primary UMs. Transcriptional profiling of PERP and caspase-8 in tumour specimens indicates that the positive association of PERP and caspase-8 proteins is a consequence of post-translational processing, most likely at the level of caspase-8 cleavage, and not of increased transcription of pro-caspase-8. We conclude that PERP expression leads to activation of an extrinsic receptor-mediated apoptotic pathway, with a possible subsequent engagement of the intrinsic apoptotic pathway. The findings underline the apoptotic pathway mediated by PERP as a critical mechanism employed by UM tumours to modulate susceptibility to apoptosis. [ABSTRACT FROM AUTHOR]

The tumor suppressor p53 has two alternative effects, causing either cell cycle arrest or apoptosis. These different effects are supposed to be mediated by the transcriptional activation of different target genes. perp, encoding a transmembrane protein of the Pmp22 family, is a transcriptional p53 target exclusively upregulated in apoptotic cells. However, its role during normal development had remained largely unclear. Here, we report the isolation and characterization of a zebrafish perp homolog. Upon overexpression in early zebrafish embryos, perp induces apoptosis. In addition, it contributes to p53-dependent and UV-induced cell death. However, during normal zebrafish development, perp displays a p53-independent and spatially restricted expression in specific cell types and tissues. Antisense-mediated loss of Perp function leads to increased apoptosis in perp-expressing cells of the developing skin and notochord. We conclude that, in contrast to its proapoptotic function in stressed cells, Perp plays an antiapoptotic role during normal zebrafish development to regulate tissue-specific cell survival.Cell Death and Differentiation (2005) 12, 52-64. doi:10.1038/sj.cdd.4401519 Published online 5 November 2004 [ABSTRACT FROM AUTHOR]

The p53 tumor suppressor gene has been implicated in the regulation of apoptosis in a number of different neuronal death paradigms. Because of the importance of p53 in neuronal injury, we questioned the mechanism underlying p53-mediated apoptosis in neurons. Using adenoviral-mediated gene delivery, reconstitution experiments, and mice carrying a knock-in mutation in the endogenous p53 gene, we show that the transactivation function of p53 is essential to induce neuronal cell death. Although p53 possesses two transactivation domains that can activate p53 targets independently, we demonstrate that the first activation domain (ADI) is required to drive apoptosis after neuronal injury. Furthermore, the BH3-only proteins Noxa and PUMA exhibit differential regulation by the two transactivation domains. Here, we show that Noxa can be induced by either activation domain, whereas PUMA induction requires both activation domains to be intact. Unlike Noxa, the upregulation of PUMA alone is sufficient to induce neuronal cell death. We demonstrate, therefore, that the first transactivation domain of p53 is indispensable for the induction of neuronal cell death. [ABSTRACT FROM AUTHOR]

Exposure to ultraviolet B (UVB) has been demonstrated to induce DNA damage as well as angiogenesis-related photo-damages, which are implicated in a variety of medical problems, including sunburn, photo-aging and skin cancers. However, the molecular mechanism related to UVB-induced photo-injuries remained fully elucidated. Here we revealed that one of the catalytic subunits of the IKK complex, IKKα, played a critical role in mediating UVB-induced apoptotic responses in two kinds of UVB sensitive cells, human keratinocyte (HaCat) and mouse embryonic fibroblasts (MEFs). This function of IKKα was unrelated to NF-κB activity, but was delivered by inducing phosphorylation and acetylation of p53 and upregulating the expression of the pro-apoptotic p53 target gene, PERP. Although IKKα kinase activity was required for mediating post-translational modifications and transactivation of 53 and PERP induction, IKKα did not show direct binding ability toward p53. Instead, IKKα could interact with CHK1, the protein kinase leading to p53 phosphorylation, and trigger CHK1 activation and CHK1/p53 complex formation. At the same time, IKKα could also interact with p300 and CBP, the acetyltransferases responsible for p53 acetylation, and trigger p300/CBP activation and p300/p53 or CBP/p53 complex formation under UVB exposure. Taken together, we have identified a novel NF-κB-independent role of IKKα in mediating UVB-induced apoptosis by regulating p53 pathway activation. Targeting IKKα/p53/PERP pathway might be helpful to prevent skin photo-damages induced by sunlight. • IKKα mediated UVB-induced apoptotic responses in both human keratinocyte (HaCat) and mouse embryonic fibroblasts (MEFs). • The role of IKKα in UVB responses was delivered by NF-κB-unrelated, but p53/PERP-dependent pathway. • IKKα functioned as a coordinator for CHK1 and p300/CBP to mediate the phosphorylation and acetylations of p53. • Manipulation of IKKα/p53/PERP pathway activation may be helpful to prevent UV damage and combat sunlight-induced skin cancer. [ABSTRACT FROM AUTHOR]

Background: Pancreatic cancer is one of the most lethal human cancers. N6-methyladenosine (m6A), a common eukaryotic mRNA modification, plays critical roles in both physiological and pathological processes. However, its role in pancreatic cancer remains elusive. Methods: LC/MS was used to profile m6A levels in pancreatic cancer and normal tissues. Bioinformatics analysis, real-time PCR, immunohistochemistry, and western blotting were used to identify the role of m6A regulators in pancreatic cancer. The biological effects of methyltransferase-like 14 (METTL14), an mRNA methylase, were investigated using in vitro and in vivo models. MeRIP-Seq and RNA-Seq were used to assess the downstream targets of METTL14. Results: We found that the m6A levels were elevated in approximately 70% of the pancreatic cancer samples. Furthermore, we demonstrated that METTL14 is the major enzyme that modulates m6A methylation (frequency and site of methylation). METTL14 overexpression markedly promoted pancreatic cancer cell proliferation and migration both in vitro and in vivo, via direct targeting of the downstream PERP mRNA (p53 effector related to PMP-22) in an m6A-dependent manner. Methylation of the target adenosine lead to increased PERP mRNA turnover, thus decreasing PERP (mRNA and protein) levels in pancreatic cancer cells. Conclusions: Our data suggest that the upregulation of METTL14 leads to the decrease of PERP levels via m6A modification, promoting the growth and metastasis of pancreatic cancer; therefore METTL14 is a potential therapeutic target for its treatment. [ABSTRACT FROM AUTHOR]

The tetraspan plasma membrane protein PERP (p 53 apoptosis e ffector r elated to P MP22) is a lesser-known transcriptional target of p53 and p63. A member of the PMP22/GAS3/EMP membrane protein family, PERP was originally identified as a p53 target specifically trans-activated during apoptosis, but not during cell-cycle arrest. Several studies have since shown downregulation of PERP expression in numerous cancers, suggesting that PERP is a tumour suppressor protein. This review focusses on the important advances made in elucidating the mechanisms regulating PERP expression and its function as a tumour suppressor in diverse human cancers, including breast cancer and squamous cell carcinoma. Investigating PERP's role in clinically-aggressive uveal melanoma has revealed that PERP engages a positive-feedback loop with p53 to regulate its own expression, and that p63 is required beside p53 to achieve pro-apoptotic levels of PERP in this cancer. Furthermore, the recent discovery of the apoptosis-mediating interaction of PERP with SERCA2b at the plasma membrane-endoplasmic reticulum interface demonstrates a novel mechanism of PERP stabilisation, and how PERP can mediate Ca2+ signalling to facilitate apoptosis. The multi-faceted role of PERP in cancer, involving well-documented functions in mediating apoptosis and cell-cell adhesion is discussed, alongside PERP's emerging roles in epithelial-mesenchymal transition, and PERP crosstalk with inflammation signalling pathways, and other signalling pathways. The potential for restoring PERP expression as a means of cancer therapy is also considered. • Pro-apoptotic plasma membrane protein PERP is a transcriptional target of p53 and p63. • PERP functions as a tumour suppressor and is downregulated in several human cancers. • Low PERP leads to reduced apoptosis and reduced adhesion of cancer cells. • PERP can engage pro-inflammatory- and Ca2+-signalling pathways. [ABSTRACT FROM AUTHOR]

Over two decades of research on cancer-associated epithelial-mesenchymal transition (EMT) led us to ascertain the occurrence of transitional intermediate states (collectively referred to as the EMT spectrum). Among the molecular factors that drive EMT, SNAI1 plays an indispensable role in regulating other core transcription factors, and this regulation is highly context-dependent. However, molecular investigation on this context-dependent regulation is still lacking. Using two ovarian cancer cell lines, we show that SNAI1 regulation on other core EMT-TFs switches from a repressive control in highly epithelial cells to an activation signaling in intermediate epithelial cells. Upon further scrutiny, we identify that the expression of early epithelial genes PERP and ERBB3 are differentially regulated in SNAI1-induced sequential EMT changes. Mechanistically, we show that changes in PERP and ERBB3 transcript levels could be correlated to the selective enrichment loss of RAD21, a cohesin component, at the distal enhancer sites of PERP and ERBB3, which precedes that of the proximal promoter-associated sites. Furthermore, the RAD21 enrichment at the distal enhancer sites is dependent on GRHL2 expression. In a nutshell, the alteration of GRHL2-associated RAD21 enrichment in epithelial genes is crucial to redefine the transition of cellular states along the EMT spectrum. [ABSTRACT FROM AUTHOR]

Acute myeloid leukemia (AML) is a malignant clonal disease that originates from hematopoietic stem cells. Because AML has a generally unsatisfactory long-term prognosis, new therapeutic options are required. To this end, we explored the effects of chidamide and decitabine alone or in combination on the AML cell lines THP-1, MV4-11, HL60, and Kasumi-1. Notably, the two drugs exhibited a synergistic effect against these cell lines. Similarly, we also found potential synergistic effects in primary cells of relapsed/refractory (r/r) AML. A transcriptome sequencing analysis performed to elucidate the underlying molecular mechanism revealed differentially expressed genes and regulatory pathways, particularly with regard to apoptosis, when comparing cells subjected to single and combination treatments. We identified PERP as a downstream target gene of the transcription factors P53 and P63, and it was expressed at considerably higher levels in combination-treated cells relative to monotherapy-treated cells. We further used a lentivirus-mediated small interfering RNA to inhibit the endogenous expression of PERP in AML cell lines and observed a significant increase in cell proliferation. Collectively, our results demonstrate, for the first time, the role of PERP in the response of AML to a combination drug regimen, providing a new potential treatment protocol and target in this context., Competing Interests: None., (AJTR Copyright © 2020.)

Little is known about the role of cell-cell adhesion in the development of mineralized tissues. Here we report that PERP, a tetraspan membrane protein essential for epithelial integrity, regulates enamel formation. PERP is necessary for proper cell attachment and gene expression during tooth development, and its expression is controlled by P63, a master regulator of stratified epithelial development. During enamel formation, PERP is localized to the interface between the enamel-producing ameloblasts and the stratum intermedium (SI), a layer of cells subjacent to the ameloblasts. Perp-null mice display dramatic enamel defects, which are caused, in part, by the detachment of ameloblasts from the SI. Microarray analysis comparing gene expression in teeth of wild-type and Perp-null mice identified several differentially expressed genes during enamel formation. Analysis of these genes in ameloblast-derived LS8 cells upon knockdown of PERP confirmed the role for PERP in the regulation of gene expression. Together, our data show that PERP is necessary for the integrity of the ameloblast-SI interface and that a lack of Perp causes downregulation of genes that are required for proper enamel formation. [ABSTRACT FROM AUTHOR]

Bladder exstrophy-epispadias complex (BEEC) is a complex and debilitating congenital disease. Familial and twin studies suggest a possible genetic component in BEEC pathogenesis. Bladder mesenchyme (detrusor) development requires induction by a signal from bladder urothelium, and we and others have shown the Shh-Gli-Bmp4 signalling pathway is likely to be involved. P63 is a master regulator in epithelial stratification and is expressed in urothelium. We have shown that p63 knock-out mice undergo excessive urothelial apoptosis. Failure of mesenchymal induction by epithelium leads to BEEC. We further demonstrated that insertion/deletion (in/del) polymorphisms (1 base pair (bp) ins and 4 bp ins., and 12 bp del) in the ΔNP63 promoter reduce transcriptional efficiency, and are associated with a statistically significant increase in the risk of BEEC in humans. Furthermore, a Genome-Wide Expression Profiling (GWEP) study suggests possible involvement of PERP in human BEEC. Intriguingly, PERP is a direct target of p63 during development, and is also involved in epithelial stratification. PERP co-localizes with desmosome, and both PERP and desmosome are essential for maintaining tissue integrity by cellular adhesion and epithelial stratification. A recent study showed that PERP and desmosome expression levels are abnormal in human BEEC patients. This review describes the role of the P63 > PERP > desmosome pathway in the development of human bladder during embryogenesis. We hypothesize that disruption of this pathway may increase the risk of BEEC., (Copyright © 2013 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.)