Changes of PI3K/AKT/BCL2 signaling proteins in congenital Giant Nevi: melanocytes contribute to their increased survival and integrity

A clinical and biologic review of congenital melanocytic nevi

Congenital melanocytic nevi (CMN) are the result of aberrations in the mitogen-activated protein kinase signal transduction pathway caused by postzygotic somatic mutations. The estimated incidence of newborns with CMN is 1%-2%. The main complications of CMN include proliferative nodules, melanomas, and neurocutaneous melanosis, and the latter two are the most troublesome issues to address. Treatments are primarily taken into account for aesthetic purposes and the reduction of melanoma risk. Due to the much lower incidence of malignant transformation observed in recent studies than in previous data, clinical management paradigms for CMN patients have gradually shifted towards conservative observation and close monitoring. Surgery and lasers are still the main treatments, and targeted therapy may be a promising strategy to help manage complications. With the increase in awareness of mental health, increasing focus has been placed on the quality of life (QoL) and psychological issues of both CMN patients and their parents. Recent studies have revealed that families coping with CMN might endure intense pressure, a major loss in QoL, and psychological problems after diagnosis and during treatment. Here, we sought to present an overview of genetic basis, complications, treatments, and psychological issues related to CMN and hope to provide better management for patients with CMN.

The role of dual-specificity phosphatase 3 in melanocytic oncogenesis

Dual-specificity phosphatase 3 (DUSP3), also known as Vaccinia H1-related phosphatase, is a protein tyrosine phosphatase that typically performs its major role in the regulation of multiple cellular functions through the dephosphorylation of its diverse and constantly expanding range of substrates. Many of the substrates described so far as well as alterations in the expression or the activity of DUSP3 itself are associated with the development and progression of various types of neoplasms, indicating that DUSP3 may be an important player in oncogenesis and a promising therapeutic target. This review focuses exclusively on DUSP3's contribution to either benign or malignant melanocytic oncogenesis, as many of the established culprit pathways and mechanisms constitute DUSP3's regulatory targets, attempting to synthesize the current knowledge on the matter. The spectrum of the DUSP3 interactions analyzed in this review covers substrates implicated in cellular growth, cell cycle, proliferation, survival, apoptosis, genomic stability/repair, adhesion and migration of tumor melanocytes. Furthermore, the speculations raised, based on the evidence to date, may be considered a fundament for potential research regarding the oncogenesis, evolution, management and therapeutics of melanocytic tumors.

Topical therapy for regression and melanoma prevention of congenital giant nevi

Giant congenital melanocytic nevi are NRAS-driven proliferations that may cover up to 80% of the body surface. Their most dangerous consequence is progression to melanoma. This risk often triggers preemptive extensive surgical excisions in childhood, producing severe lifelong challenges. We have presented preclinical models, including multiple genetically engineered mice and xenografted human lesions, which enabled testing locally applied pharmacologic agents to avoid surgery. The murine models permitted the identification of proliferative versus senescent nevus phases and treatments targeting both. These nevi recapitulated the histologic and molecular features of human giant congenital nevi, including the risk of melanoma transformation. Cutaneously delivered MEK, PI3K, and c-KIT inhibitors or proinflammatory squaric acid dibutylester (SADBE) achieved major regressions. SADBE triggered innate immunity that ablated detectable nevocytes, fully prevented melanoma, and regressed human giant nevus xenografts. These findings reveal nevus mechanistic vulnerabilities and suggest opportunities for topical interventions that may alter the therapeutic options for children with congenital giant nevi.

Transcriptome Analysis of Large to Giant Congenital Melanocytic Nevus Reveals Cell Cycle Arrest and Immune Evasion: Identifying Potential Targets for Treatment

Large to giant congenital melanocytic nevus (lgCMN) is a benign cutaneous tumor that develops during embryogenesis. A large number of lgCMN patients are ineligible for surgical treatment; hence, there is an urgent need to develop pharmacological treatments. Clinically, tumorigenesis and progression essentially halt after birth, resulting in the homeostasis of growth arrest and survival. Numerous studies have employed whole-genome or whole-exome sequencing to clarify the etiology of lgCMN; however, transcriptome sequencing of lgCMN is still lacking. Through comprehensive transcriptome analysis, this study elucidated the ongoing regulation and homeostasis of lgCMN and identified potential targets for treatment. Transcriptome sequencing, identification of differentially expressed genes and hub genes, protein–protein network construction, functional enrichment, pathway analysis, and gene annotations were performed in this study. Immunohistochemistry, real-time quantitative PCR, immunocytofluorescence, and cell cycle assays were employed for further validation. The results revealed several intriguing phenomena in lgCMN, including P16-induced cell cycle arrest, antiapoptotic activity, and immune evasion caused by malfunction of tumor antigen processing. The arrested cell cycle in lgCMN is consistent with its phenotype and rare malignant transformation. Antiapoptotic activity and immune evasion might explain how such heterogeneous cells have avoided elimination. Major histocompatibility complex (MHC) class I-mediated tumor antigen processing was the hub pathway that was significantly downregulated in lgCMN, and ITCH, FBXW7, HECW2, and WWP1 were identified as candidate hub genes. In conclusion, our research provides new perspectives for immunotherapy and targeted therapy.

Pristimerin synergistically sensitizes conditionally reprogrammed patient derived-primary hepatocellular carcinoma cells to sorafenib through endoplasmic reticulum stress and ROS generation by modulating Akt/FoxO1/p27kip1 signaling pathway

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-associated mortality worldwide. Sorafenib (SORA), as a first-line therapeutic drug, has been used to treat HCC, but resistance poses a major limitation on the efficacy of SORA chemotherapy. Pristimerin (PRIS), a natural bioactive component isolated from various plant species in the Celastraceae and Hippocrateaceae families, has been reported to exhibit outstanding antitumor effects in several types of cells in vitro.

PURPOSE

The aim of this study was to investigate whether PRIS can exert synergistic anti-tumor effects with the combination of SORA, and if so, through what mechanism.

METHODS

Conditionally reprogrammed patient derived-primary hepatocellular carcinoma cells (CRHCs) were isolated from human liver cancer tissues and treated with SORA and PRIS. Cell proliferation, apoptosis, migration and tube formation ability were detected by DNA content quantification, flow cytometry, transwell assay and Matrigel-based angiogenesis assay. Gene and protein expression were assessed by qRT-PCR and Western blot respectively.

RESULTS

Initially, we observed that the combination of the two drugs had a much stronger inhibitory effect on CRHCs growth than either drug alone. Moreover, the combination of 2 µM SORA and 1 µM PRIS exhibited a significant anti‑migrative and anti-invaded effect on CRHCs, and remarkably inhibited capillary structure formation of Human Umbilical Vein Endothelial Cells (HUVECs). Furthermore, the combined treatment with SORA and PRIS synergistically induced intrinsic apoptosis in CRHCs, involving a caspase-4-dependent mechanism paralleled by an increased Bax/Bcl-xL ratio. These activities were mediated through ROS generation and the induction of endoplasmic reticulum (ER) stress and mitochondrial dysfunction. GRP78 silencing or ER stress inhibitor 4-phenylbutyric acid administration was revealed to abolish the anticancer effects of PRIS, indicating the critical role of GRP78 in mediating the bioactivity of PRIS. The present study also provides mechanistic evidence that PRIS modulated the Akt/FoxO1/p27^kip1 signaling pathway, which is required for mitochondrial-mediated intrinsic apoptosis, activation of ER stress, and stimulation of caspase-4 induced by PRIS, and, consequently resulting in suppressed cell viability, migration and angiogenesis co-treated with SORA in CRHCs.

CONCLUSION

Our results suggest the use of PRIS as sensitizers of chemotherapy paving the way for innovative and promising targeted chemotherapy-based therapeutic strategies in human HCC.

Uev1A promotes breast cancer cell survival and chemoresistance through the AKT-FOXO1-BIM pathway

Background

Ubiquitin-conjugating enzyme variant UEV1A is required for Ubc13-catalyzed K63-linked poly-ubiquitination that regulates several signaling pathways including NF-κB, MAPK and PI3K/AKT. Previous reports implicate UEV1A as a potential proto-oncogene and have shown that UEV1A promotes breast cancer metastasis through constitutive NF-кB activation. Ubc13-Uev1A along with TARF6 can also ubiquitinate AKT but its downstream events are unclear.

Methods

In this study, we experimentally manipulated UEV1 expression in two typical breast cancer cell lines MDA-MB-231 and MCF7 under serum starvation conditions and monitored AKT activation and its downstream protein levels, as well as cellular sensitivity to chemotherapeutic agents.

Results

We found that overexpression of UEV1A is sufficient to activate the AKT signaling pathway that in turn inhibits FOXO1 and BIM expression to promote cell survival under serum starvation conditions and enhances cellular resistance to chemotherapy. Consistently, experimental depletion of Uev1 in breast cancer cells inhibits AKT signaling and promotes FOXO1 and BIM expression to reduce cell survival under serum starvation stress and enhance chemosensitivity.

Conclusions

Uev1A promotes cell survival under serum starvation stress through the AKT-FOXO1-BIM axis in breast cancer cells, which unveals a potential therapeutic target in the treatment of breast cancers.

Fusobacterium nucleatum Facilitates Apoptosis, ROS Generation, and Inflammatory Cytokine Production by Activating AKT/MAPK and NF-κB Signaling Pathways in Human Gingival Fibroblasts

Fusobacterium nucleatum (F. nucleatum) plays key roles in the initiation and progression of periodontitis. However, the pathogenic effect of F. nucleatum on human oral tissues and cells has not been fully evaluated. In this study, we aimed to analyze the pathogenic effects of F. nucleatum on human gingival fibroblasts (GFs) and clarify the potential mechanisms. RNA-sequencing analysis confirmed that F. nucleatum significantly altered the gene expression of GF as the stimulation time increased. Cell counting and EdU-labeling assays indicated that F. nucleatum inhibited GF proliferation and promoted cell apoptosis in a time- and dose-dependent manner. In addition, cell apoptosis, intracellular reactive oxygen species (ROS) generation, and proinflammatory cytokine production were dramatically elevated after F. nucleatum stimulation. Furthermore, we found that the AKT/MAPK and NF-κB signaling pathways were significantly activated by F. nucleatum infection and that a large number of genes related to cellular proliferation, apoptosis, ROS, and inflammatory cytokine production downstream of AKT/MAPK and NF-κB signaling pathways were significantly altered in F. nucleatum-stimulated GFs. These findings suggest that F. nucleatum inhibits GF proliferation and promotes cell apoptosis, ROS generation, and inflammatory cytokine production partly by activating the AKT/MAPK and NF-κB signaling pathways. Our study opens a new window for understanding the pathogenic effects of periodontal pathogens on the host oral system.

Differential Expression Pattern of Exosome Long Non-Coding RNAs (lncRNAs) and MicroRNAs (miRNAs) in Vascular Endothelial Cells Under Heat Stroke

BACKGROUND Heat stroke is a life-threatening disease which is characterized by a high body temperature and multiple organ dysfunction syndrome. Vascular endothelial cell injury is a main feature of heat stroke. Little is known about the long noncoding RNA (lncRNA) and microRNA (miRNA) expression alternation in endothelial cell exosomes related to heat stroke. The aim of this study was to explore the changes of lncRNAs and miRNAs expression pattern in exosomes derived from vascular endothelial cells under heat stroke temperature conditions. MATERIAL AND METHODS Cultured medium exosomes from HUVECs (human vascular endothelial cells) either under normal temperature or heat stroke temperature conditions were harvested; then RNA was extracted and the lncRNAs and miRNAs were analyzed by high throughput sequencing. RESULTS Ten significantly upregulated and 10 downregulated lncRNAs were identified in exosomes derived from heat stroke temperature treated cells. Furthermore, GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) analyses were used to evaluate the signaling pathway of differential expressions in lncRNAs. Finally, the interaction network of lncRNAs-miRNAs-mRNA was uncovered using ceRNA (competing endogenous RNA) principle via prediction software. CONCLUSIONS These results indicate that the identified lncRNAs and miRNAs in endothelial cell exosomes might serve as non-invasive biomarkers for heat stroke.

Phosphorylation of Bcl-2 plays an important role in glycochenodeoxycholate-induced survival and chemoresistance in HCC

Hepatocellular carcinoma (HCC) is a highly malignant tumor and can evolve rapidly to resistance to chemotherapies. Glycochenodeoxycholate (GCDA), which is toxic and hydrophobic, is the main ingredient in the bile and associated with carcinogenesis of gastrointenstinal tumors. Bcl-2 is the most important anti-apoptotic protein and overexpressed in various human tumors. In the present study, we found that GCDA can induce the chemoresistance of human liver cancer cells and specific depletion of Bcl-2 by RNA interference blocks GCDA-stimulated chemoresistance, which indicate the pivotal role of Bcl-2 in such process. Mechanistically, GCDA simultaneously stimulates phosphorylation of Bcl-2 at Ser70 site and activates extracellular signal-regulated kinase 1/2 (ERK1/2), and inhibition of ERK1/2 by PD98059 (MAPK/ERK1/2 inhibitor) or siRNA (targeting ERK1/2) suppresses GCDA-stimulated phosphorylation of Bcl-2 and significantly attenuates the survival and chemoresistance induced by GCDA in liver cancer cells. Thus, GCDA-induced survival and chemoresistance of liver cancer cells may occur through activation of Bcl-2 by phosphorylation at Ser70 site through MAPK/ERK1/2 pathway, which may contribute to the development of human liver cancer and chemoresistance.

Ghrelin reduces liver impairment in a model of concanavalin A-induced acute hepatitis in mice

Background and aims

Ghrelin is a 28-amino-acid gut hormone that was first discovered as a potent growth hormone secretagogue. Recently, it has been shown to exert a strong anti-inflammatory effect. The purpose of the study reported here was to explore the effect and mechanism of ghrelin on concanavalin (Con) A-induced acute hepatitis.

Methods

Balb/C mice were divided into four groups: normal control (NC) (mice injected with vehicle [saline]); Con A (25 mg/kg); Con A + 10 μg/kg ghrelin; and Con A + 50 μg/kg ghrelin (1 hour before Con A injection). Pro-inflammatory cytokine levels were detected. Protein levels of phosphoinositide 3-kinase (PI3K); phosphorylated Akt (p-Akt); caspase 3, 8, and 9; and microtubule-associated protein 1 light chain 3 (LC3) were also detected. Perifosine (25 mM) (an Akt inhibitor) was used to investigate whether the protective effect of ghrelin was interrupted by an Akt inhibitor. Protein levels of p-AKT; Bcl-2; Bax; and caspase 3, 8, and 9 were also detected.

Results

Aspartate aminotransferase, alanine aminotransferase, and pathological damage were significantly ameliorated by ghrelin pretreatment in Con A-induced hepatitis. Inflammatory cytokines were significantly reduced by ghrelin pretreatment. Bcl-2; Bax; and caspase 3, 8, and 9 expression were also clearly affected by ghrelin pretreatment, compared with the Con A-treated group. However, the Akt kinase inhibitor reversed the decrease of Bax and caspase 3, 8, 9, and reduced the protein level of p-Akt and Bcl-2. Ghrelin activated the PI3K/Akt/Bcl-2 pathway and inhibited activation of autophagy.

Conclusion

Our results demonstrate that ghrelin attenuates Con A-induced acute immune hepatitis by activating the PI3K/Akt pathway and inhibiting the process of autophagy, which might be related to inhibition of inflammatory cytokine release, and prevention of hepatocyte apoptosis. These effects could be interrupted by an Akt kinase inhibitor.

A systems-biological study on the identification of safe and effective molecular targets for the reduction of ultraviolet B-induced skin pigmentation

Melanogenesis is the process of melanin synthesis through keratinocytes-melanocytes interaction, which is triggered by the damaging effect of ultraviolet-B (UVB) rays. It is known that melanogenesis influences diverse cellular responses, including cell survival and apoptosis, via complex mechanisms of feedback and crosstalk. Therefore, an attempt to suppress melanin production by modulating the melanogenesis pathway may induce perturbations in the apoptotic balance of the cells in response to UVB irradiation, which results in various skin diseases such as melasma, vitiligo, and skin cancer. To identify such appropriate target strategies for the reduction of UVB-induced melanin synthesis, we reconstructed the melanogenesis signaling network and developed a Boolean network model. Mathematical simulations of the melanogenesis network model revealed that the inhibition of beta-catenin in the melanocytes effectively reduce melanin production while having minimal influence on the apoptotic balance of the cells. Exposing cells to a beta-catenin inhibitor decreased pigmentation but did not significantly change the B-cell Chronic lymphocytic leukemia/lymphoma 2 expression, a potent regulator of apoptotic balance. Thus, our systems analysis suggests that the inhibition of beta-catenin may be the most appropriate target strategy for the reduction of UVB-induced skin pigmentation.

Downregulated miR-495 [Corrected] Inhibits the G1-S Phase Transition by Targeting Bmi-1 in Breast Cancer

Bmi-1 (B cell-specific Moloney murine leukemia virus integration site 1) is upregulated in breast cancer and was involved in many malignant progressions of breast cells, including cell proliferation, stem cell pluripotency, and cancer initiation. However, the epigenetic regulatory mechanism of Bmi-1 in breast cancer remains unclear. After analysis of the ArrayExpress dataset GSE45666, we comparatively detected the expression levels of miR-495 in 9 examined breast cancer cell lines, normal breast epithelial cells and 8 pairs of fresh clinical tumor samples. Furthermore, to evaluate the effect of miR-495 on the progression of breast cancer, MCF-7 and MDA-MB-231 were transduced to stably overexpress miR-495. The 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, colony formation assays, 5-Bromo-2-deoxyUridine labeling and immunofluorescence, anchorage-independent growth ability assay, flow cytometry analysis, and luciferase assays were used to test the effect of miR-495 in MCF-7 and MDA-MB-231 cells in vitro. Xenografted tumor model was also used to evaluate the effect of miR-495 in breast cancer. Herein, we found that miR-495, a predicted regulator of Bmi-1, was frequently downregulated in malignant cells and tissues of breast. Upregulation of miR-495 significantly suppressed breast cancer cell proliferation and tumorigenicity via G1-S arrest. Further analysis revealed that miR-495 targeted Bmi-1 through its 3' untranslated region. Moreover, Bmi-1 could neutralize the suppressive effect of miR-495 on cell proliferation and tumorigenicity of breast cancer in vivo. These data suggested that miR-495 could inhibit the G1-S phase transition that leads to proliferation and tumorigenicity inhibition by targeting and suppressing Bmi-1 in breast cancer.