Growth Of Human Melanoma Cells Research Articles

Abstract 2308 In-vitro Combo Treatment of Human Liver Cancer Cell (Hep-G2) Line with a Cocktail that had Inhibited Human Melanoma Cell Growth

Abstract 2308 In-vitro Combo Treatment of Human Liver Cancer Cell (Hep-G2) Line with a Cocktail that had Inhibited Human Melanoma Cell Growth

Evodiamine inhibits growth of vemurafenib drug-resistant melanoma via suppressing IRS4/PI3K/AKT signaling pathway.

Evodiamine, a novel alkaloid, was isolated from the fruit of tetradium. It exerts a diversity of pharmacological effects and has been used to treat gastropathy, hypertension, and eczema. Several studies reported that evodiamine has various biological effects, including anti-nociceptive, anti-bacterial, anti-obesity, and anti-cancer activities. However, there is no research regarding its effects on drug-resistant cancer. This study aimed to investigate the effect of evodiamine on human vemurafenib-resistant melanoma cells (A375/R cells) proliferation ability and its mechanism. Cell activity was assessed using the cell counting kit-8 (CCK-8) method. Flow cytometry assay was used to assess cell apoptosis and cell cycle. A xenograft model was used to analyze the inhibitory effects of evodiamine on tumor growth. Bioinformatics analyses, network pharmacology, and molecular docking were used to explore the potential mechanism of evodiamine in vemurafenib-resistant melanoma. RT-qPCR and Western blotting were performed to reveal the molecular mechanism. The alkaloid extract of the fruit of tetradium, evodiamine showed the strongest tumor inhibitory effect on vemurafenib-resistant melanoma cells compared to treatment with vemurafenib alone. Evodiamine inhibited vemurafenib-resistant melanoma cell growth, proliferation, and induced apoptosis, conforming to a dose-effect relationship and time-effect relationship. Results from network pharmacology and molecular docking suggested that evodiamine might interact with IRS4 to suppress growth of human vemurafenib-resistant melanoma cells. Interestingly, evodiamine suppressed IRS4 expression and then inhibited PI3K/AKT signaling pathway, and thus had the therapeutic action on vemurafenib-resistant melanoma.

Role of Nudt2 in Anchorage-Independent Growth and Cell Migration of Human Melanoma.

Nudt2 encodes a diadenosine tetraphosphate (Ap4A) hydrolase that catalyzes the hydrolysis of Ap4A and is involved in the lysyl tRNA synthetase-Ap4A-Nudt2 (LysRS-Ap4A-Nudt2) signaling pathway. We have previously demonstrated that this pathway is active in non-small cell lung cancer. Nudt2 was shown to be involved in cell proliferation in breast cancer, making it an important target in cancer therapy. Currently, the function of Nudt2 in malignant melanoma has not been demonstrated. Therefore, we investigated the role played by Nudt2 in the growth of human melanoma. Our study showed that Nudt2 knockdown suppressed anchorage-independent growth of human melanoma cells in vitro. The in vivo effect of Nudt2 was determined by investigating the role played by Nudt2 knockdown on the ability of the cells to form tumors in a mice xenograft model. Nudt2 knockdown significantly suppressed tumor growth in this model. Moreover, overexpression of Nudt2 resulted in an increase in anchorage-independent growth of these cells, whereas Nudt2 knockdown decreased their migration. In addition, Nudt2 knockdown reduced vimentin expression. Vimentin is one of the mesenchymal markers that are involved in the epithelial mesenchymal transition (EMT) process. Thus, Nudt2 plays an important role in promoting anchorage-independent growth and cell migration in melanoma.

Abstract 5287: Is testosterone the male sex hormone responsible for increased male mortality in melanoma? In-vitro studies based on human melanoma (BLM) cell model

Abstract Clinical studies showed that menstruating females were better protected in melanoma than post-menopausal women and men of any age. But, these studies did not correlate with the steroid status of females. Our in-vitro study with progesterone (P), a female sex hormone showed significant inhibition of human melanoma cell growth. A literature survey showed that progesterone levels ranged between 1000-1500 ng/dl in menstruating females compared to post-menopausal women (20-100 ng/dl) and men (27-90 ng/dl), suggesting increased progesterone levels could offer protection to the menstruating females. Moreover, Elisarray showed that progesterone action was mediated by specific suppression of proinflammatory cytokine IL-8. So, it was proposed that a low level of progesterone in males leading to non-suppression of IL-8 in melanoma, could be responsible for increased melanoma cell growth and male mortality. This hypothesis prompted us to check the effect of male sex hormones androstenedione (AD) and testosterone (T) on melanoma cell growth and IL-8 secretion. Both AD and T decreased IL-8 secretion along with a decrease in cell growth. However, when progesterone was added along with androgens, there was a significant decrease in cell growth and in IL-8 secretion. This raised the question of why male mortality was high when androgens also decreased cell growth and IL-8 secretion. In order to address this question, it was decided to induce endogenous IL-8 in melanoma cells by pre-incubating with endothelin (50ng/ml) and then add steroids. AD and P individually decreased IL-8 secretion and in combination significantly decreased IL-8 secretion and cell growth even in endothelin pretreated cells when compared to their respective control cells. But, T was not able to suppress endogenous IL-8 induced by endothelin and in fact, cell growth also was slightly increased compared to straight T-treated cells. Conclusion: So, in males 2 reasons 1) a deficiency of progesterone and 2) inefficiency of T to suppress endogenous IL-8 could possibly result in increased IL-8 levels. This increased IL-8 level in males could lead to increased cell growth and metastasis in melanoma (IL-8 had already been shown to stimulate melanoma cell growth and metastasis by us and others) leading to death. So, a situation arising out of male reproductive endocrine physiology could probably be responsible for increased male mortality in melanoma. Citation Format: Pandurangan Ramaraj. Is testosterone the male sex hormone responsible for increased male mortality in melanoma? In-vitro studies based on human melanoma (BLM) cell model. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5287.

New in vitro findings about halogenated boroxine cytotoxicity and deregulation of cell death-related genes in GR-M melanoma cells.

Anti-proliferative effects of halogenated boroxine - K2(B3O3F4OH) (HB) - have been confirmed in multiple cancer cell lines, including melanoma, but the exact mechanism of action is still unknown. This study aimed to determine its cytotoxic effects on human Caucasian melanoma (GR-M) cell growth in vitro as well as on the expression of cell death-related genes BCL-2, BECN1, DRAM1, and SQSTM1. GR-M and peripheral blood mononuclear (PBM) cells were treated with different HB concentrations and their growth inhibition and relative gene expression profiles were determined using the Alamar blue assay and real-time PCR. HB significantly inhibited cell growth of both GR-M and PBM cells but was even more effective in GR-M melanoma cells, as significant inhibition occurred at a lower HB concentration of 0.2 mg/mL. GR-M BCL-2 expression was significantly downregulated (P=0.001) at HB concentration of 0.4 mg/mL, which suggests that HB is a potent tumour growth inhibitor. At the same time, it upregulated BCL-2 expression in normal (PBM) cells, probably by activating protective mechanisms against induced cytotoxicity. In addition, all but the lowest HB concentrations significantly upregulated SQSTM1 (P=0.001) in GR-M cells. Upregulated BECN1 expression suggests early activation of autophagy at the lowest HB concentration in SQSTM1 cells and at all HB concentrations in PBM cells. Our findings clearly show HB-associated cell death and, along with previous cytotoxicity studies, reveal its promising anti-tumour potential.

Dieckol Inhibits Autophagic Flux and Induces Apoptotic Cell Death in A375 Human Melanoma Cells via Lysosomal Dysfunction and Mitochondrial Membrane Impairment.

Dieckol is a natural brown algal-derived polyphenol and its cytotoxic potential against various types of cancer cells has been studied. However, the effects of dieckol on autophagy in cancer cells remain unknown. Here, we show that dieckol inhibits the growth of A375 human melanoma cells by inducing apoptotic cell death, which is associated with lysosomal dysfunction and the inhibition of autophagic flux. Dieckol induces autophagosome accumulation by inhibiting autophagosome-lysosome fusion. Moreover, dieckol not only triggers lysosomal membrane permeabilization, followed by an increase in lysosomal pH and the inactivation of cathepsin B and D, but also causes the loss of mitochondrial membrane potential. Importantly, a cathepsin D inhibitor partially relieved dieckol-induced mitochondrial membrane impairment and caspase-mediated apoptosis. Collectively, our findings indicate that dieckol is a novel autophagy inhibitor that induces apoptosis-mediated cell death via lysosomal dysfunction and mitochondrial membrane impairment in A375 human melanoma cells. This suggests the novel potential value of dieckol as a chemotherapeutic drug candidate for melanoma treatment.

Potential of Epidermal Growth Factor-like Peptide from the Sea Cucumber Stichopus horrens to Increase the Growth of Human Cells: In Silico Molecular Docking Approach.

The sea cucumber is prominent as a traditional remedy among Asians for wound healing due to its high capacity for regeneration after expulsion of its internal organs. A short peptide consisting of 45 amino acids from transcriptome data of Stichopus horrens (Sh-EGFl-1) shows a convincing capability to promote the growth of human melanoma cells. Molecular docking of Sh-EGFl-1 peptide with human epidermal growth factor receptor (hEGFR) exhibited a favorable intermolecular interaction, where most of the Sh-EGFl-1 residues interacted with calcium binding-like domains. A superimposed image of the docked structure against a human EGF–EGFR crystal model also gave an acceptable root mean square deviation (RMSD) value of less than 1.5 Å. Human cell growth was significantly improved by Sh-EGFl-1 peptide at a lower concentration in a cell proliferation assay. Gene expression profiling of the cells indicated that Sh-EGFl-1 has activates hEGFR through five epidermal growth factor signaling pathways; phosphoinositide 3-kinase (PI3K), mitogen-activated protein kinase (MAPK), phospholipase C gamma (PLC-gamma), Janus kinase-signal transducer and activator of transcription (JAK-STAT) and Ras homologous (Rho) pathways. All these pathways triggered cells’ proliferation, differentiation, survival and re-organization of the actin cytoskeleton. Overall, this marine-derived, bioactive peptide has the capability to promote proliferation and could be further explored as a cell-growth-promoting agent for biomedical and bioprocessing applications.

Transcription factor YY1 contributes to human melanoma cell growth through modulating the p53 signalling pathway

Melanoma has a higher mortality rate than any other skin cancer, and its cases are increasing. The transcription factor YY1 has been proven to be involved in tumour progression; however, the role of YY1 in melanoma is not well understood. This study investigates how YY1 functions in melanoma progression, and it also elucidates the underlying mechanisms involved. We have found that in clinical human melanoma tissues, YY1 is overexpressed compared with YY1 expression in normal melanocytes and skin tissues. Cellular immunofluorescence shows that YY1 is mainly located in the nucleus. YY1 knockdown reduces proliferation, migration and invasion of melanoma cell lines. Moreover, the apoptosis rate of cells is significantly increased in low-YY1 environments. The overexpression of YY1 resulted in decreased apoptotic rates in melanoma cells. YY1 also affects the expression of EMT-related proteins. Additional experiments reveal that YY1 knockdown disrupts the interaction of MDM2-p53, and that it both stabilizes and increases p53 activity. The upregulation of p53 expression in turn stimulates p21 expression just as it suppresses CDK4 expression, which then induces cells that were arrested in the G1 phase. The effect then is to constrain cell proliferation in melanoma cells. Upon activation of the p53 pathway, Bax, a pro-apoptotic protein, is upregulated, and Bcl-2, an anti-apoptotic protein, was downregulated in A375 cells. The findings of this study provide novel insights into the pathology of melanoma as well as the role that YY1 plays in tumour progression. The findings also suggest that targeting YY1 has the potential to improve the diagnosis and treatment of melanoma.

3D Bioprinted GelMA/PEGDA Hybrid Scaffold for Establishing an In Vitro Model of Melanoma.

Due to the high incidence of malignant melanoma, the establishment of in vitro models that recapitulate the tumor microenvironment is of great biological and clinical importance for tumor treatment and drug research. In this study, 3D printing technology was used to prepare GelMA/PEGDA composite scaffolds that mimic the microenvironment of human malignant melanoma cell (A375) growth and construct in vitro melanoma micro-models. The GelMA/PEGDA hybrid scaffold was tested by the mechanical property, cell live/dead assay, cell proliferation assay, cytoskeleton staining and drug loading assay. The growth of tumor cells in two- and three-dimensional culture systems and the anti-cancer effect of luteolin were evaluated using the live/dead staining method and the Cell Counting Kit-8 (CCK-8) method. The results showed a high aggregation of tumor cells on the 3D scaffold, which was suitable for long-term culture. Cytoskeleton staining and immunofluorescent protein staining were used to evaluate the degree of differentiation of tumor cells under 2D and 3D culture systems. The results indicated that 3D bioprinted scaffolds were more suitable for tumor cell expansion and differentiation, and the tumor cells were more aggressive. In addition, luteolin was time- and dose-dependent on tumor cells, and tumor cells in the 3D culture system were more resistant to the drug.

Chitosan Nanoparticles Containing Cinnamomum verum J.Presl Essential Oil and Cinnamaldehyde; Preparation, Characterization and Anticancer Effects Against Melanoma and Breast Cancer Cells

Cancer is the second leading cause of death worldwide, and due to the emergence of resistance to synthetic drugs in different cancers, developing new green drugs have become crucial. In this study, chitosan nanoparticles containing Cinnamomum verum J.Presl essential oil and cinnamaldehyde (major ingredient) were first prepared. The obtained nanoparticles were then characterized using Dynamic Light Scattering (DLS), Transmission electron microscopy (TEM), and Attenuated Total Reflection-Fourier Transform InfraRed (ATR-FTIR). After that, anticancer effects of the as-prepared nanoparticles were investigated. IC50 values of chitosan nanoparticles containing the essential oil were observed at 79 and 112 µg/mL against A-375 and MDA-MB-468 cells, respectively. These values for chitosan nanoparticles containing cinnamaldehyde were obtained at 135 and 166 µg/mL. The results of the current study indicated that chitosan nanoparticles containing C. verum essential oil can inhibit the growth of human melanoma (A-375) and breast cancer (MDA-MB-468) cells.

CLEC12B Decreases Melanoma Proliferation by Repressing Signal Transducer and Activator of Transcription 3

The potential role of CLEC12B, a gene predominantly expressed by skin melanocytes discovered through transcriptomic analysis, in melanoma is unknown. In this study, we show that CLEC12B expression is lower in melanoma and melanoma metastases than in melanocytes and benign melanocytic lesions and that its decrease correlates with poor prognosis. We further show that CLEC12B recruits SHP2 phosphatase through its immunoreceptor tyrosine-based inhibition motif domain, inactivates signal transducer and activator of transcription 1/3/5, increases p53/p21/p27 expression/activity, and modulates melanoma cell proliferation. The growth of human melanoma cells overexpressing CLEC12B in nude mice after subcutaneous injection is significantly decreased compared with that in the vehicle control group and is associated with decreased signal transducer and activatorof transcription 3 phosphorylation and increased p53 levels in the tumors. Reducing the level of CLEC12B had the opposite effect. We show that CLEC12B represses the activation of the signal transducer and activator of transcription pathway and negatively regulates the cell cycle, providing a proliferative asset to melanoma cells.

In-Vitro Effects of Active Vitamin-D3 and Vitamin-A on Human Melanoma (BLM and1205Lu) Cell Growth

Though UV ray in the Sun light is essential for vitamin-D3 formation, yet UV rays can lead to skin cancer. Lack of vitamin-D3 also can lead to cancer. Hence, we decided to study the effect of vitamin-D3 on human melanoma cell models. Our aims were to study the in-vitro effects of vitamin-D3 and vitamin-A on human melanoma (BLM, 1205Lu) cell growth, as vitamins D3 and A are important for a healthy skin. Initially dose-curve (100 nM to 100 μM concentration) study was carried out with vitamin-D3 and vitamin-A (retinoic acid) on BLM cells to determine the optimal concentrations of vitamins-D3 and A for co-incubation with progesterone (50 μM) and RU-486 (50 μM). Supernatants from the treated cells were subjected to Elisarray. Vitamin-D3 and vitamin-A showed a dose-dependent decrease in cell growth. Based on the dose-curve, it was decided to use 25 μM (at 57% cell growth) of vitamin-D3 and 50 μM (at 55% cell growth) of vitamin-A for co-incubation studies. Co-incubation of vitamin-D3 with vitamin-A showed an additive effect on the decrease of BLM cell growth (20%). Similarly co-incubation of vitamin-D3 with progesterone (33% cell growth) and with RU-486 (28% cell growth) as well as co-incubation of vitamin-A with progesterone (31% cell growth) and RU-486 (18% cell growth) showed an additive effect on the decrease of BLM cell growth. Based on the BLM co-incubation studies, we decided to repeat the studies on 1205Lu cells. So, 25 μM (at 34% cell growth) of vitamin-D3 and 50 μM (at 44% cell growth) of vitamin-A were used for co-incubation studies. Co-incubation of vitamin-D3 with vitamin-A showed an additive effect on the decrease of cell growth (22%). Though co-incubation of vitamin-D3 with progesterone did not show any difference in cell growth (51%), yet co-incubation with RU-486 showed a decrease in 1205Lu cell growth (21%). Similarly co-incubation of vitamin-A with progesterone (25% cell growth) and with RU-486 (23% cell growth) showed a synergistic effect on the decrease of 1205Lu cell growth. Conclusion: These studies suggested that combination of vitamins and steroids might be effective in decreasing melanoma cell growth. Hence, various combination of vitamins and steroids will be tested for their effect on melanoma cell growth in vitro in order to develop a combo drug treatment for melanoma.

Combined Effect of Vitamin‐D3 and Progesterone on In‐Vitro Human Melanoma (BLM) Cell Growth

Our previous study showed that steroids especially progesterone and RU-486 significantly inhibited human melanoma (BLM) cell growth in-vitro. As lack of vitamin-D can lead to cancer and vitamin-D is synthesized in the skin by the UV rays, we decided to check the combined effect of vitamin-D3 and progesterone on human melanoma cell growth. Along with vitamin-D3, we also decided to include vitamin-A and RU-486.So our aimswere to check the in-vitro effects of active vitamin-D3 and vitamin-A combined with progesterone and RU-486 on human melanoma (BLM) cell growth. Initially dose-curve (100 nM to 100 µM concentration) study was carried out with vitamin-D3 and vitamin-A (retinoic acid) to determine the optimal concentrations of vitamins-D3 and A for co-incubation with progesterone (50 µM) and RU-486 (50 µM). Vitamin-D3 and vitamin-A showed a dose-dependent decrease in cell growth. Based on the dose-curve, it was decided to use 25 µM (at 57% cell growth) of vitamin-D3 and 50 µM (at 55% cell growth) of vitamin-A for co-incubation between them and also with progesterone and RU-486 separately. Co-incubation of vitamin-D3 and vitamin-A showed an additive effect on the decrease of cell growth (at 20%). Similarly co-incubation of vitamin-D3 with progesterone (at 33% cell growth) and RU-486 (at 28% cell growth) as well as co-incubation of vitamin-A with progesterone (at 31% cell growth) and RU-486 (at 18% cell growth) showed an additive effect on the decrease of cell growth. Since our previous study also showed the involvement of IL-8 in the regulation of melanoma cell growth, supernatants from the treated cells were subjected to Elisarray. There was a decrease in IL-8 secretion with vitamin-D3 treatment. But, vitamin-A alone treatment showed an increase in IL-8 secretion. However, co-incubation of vitamin-A with vitamin-D3, progesterone and RU-486 showed a decrease in IL-8 secretion. These studies suggested that a combination of vitamins and steroids might be effective in decreasing melanoma cell growth than vitamin or steroid alone. Conclusion Co-incubation of vitamins with steroids indicated a combo drug effect on the decrease of melanoma cell growth. Hence, various combinations of vitamin-D3, vitamin-A and steroids would be tested for their effect on melanoma cell growth in vitro.

Targeting p53 for Melanoma Treatment: Counteracting Tumour Proliferation, Dissemination and Therapeutic Resistance.

Simple SummaryMelanoma is a highly metastatic and therapy-resistant cancer and is therefore associated with low survival rates of patients. In melanoma, the inactivation of the wild-type form of the p53 tumour suppressor protein is a frequent event, mainly through interactions with MDM2 and MDMX. In this work, our recently disclosed p53-activating agent, SLMP53-2, displayed promising in vitro and in vivo antitumour activity, with particular impacts on melanoma migration and invasion. Moreover, SLMP53-2 (re)sensitized melanoma cells to clinically used chemotherapeutic agents, potentially overcoming the therapeutic resistance issue. As a whole, the p53 activator SLMP53-2 may represent a new therapeutic opportunity for melanoma, particularly in combination with MAPK pathway-targeting drugs.Melanoma is the deadliest form of skin cancer, primarily due to its high metastatic propensity and therapeutic resistance in advanced stages. The frequent inactivation of the p53 tumour suppressor protein in melanomagenesis may predict promising outcomes for p53 activators in melanoma therapy. Herein, we aimed to investigate the antitumor potential of the p53-activating agent SLMP53-2 against melanoma. Two- and three-dimensional cell cultures and xenograft mouse models were used to unveil the antitumor activity and the underlying molecular mechanism of SLMP53-2 in melanoma. SLMP53-2 inhibited the growth of human melanoma cells in a p53-dependent manner through induction of cell cycle arrest and apoptosis. Notably, SLMP53-2 induced p53 stabilization by disrupting the p53–MDM2 interaction, enhancing p53 transcriptional activity. It also promoted the expression of p53-regulated microRNAs (miRNAs), including miR-145 and miR-23a. Moreover, it displayed anti-invasive and antimigratory properties in melanoma cells by inhibiting the epithelial-to-mesenchymal transition (EMT), angiogenesis and extracellular lactate production. Importantly, SLMP53-2 did not induce resistance in melanoma cells. Additionally, it synergized with vemurafenib, dacarbazine and cisplatin, and resensitized vemurafenib-resistant cells. SLMP53-2 also exhibited antitumor activity in human melanoma xenograft mouse models by repressing cell proliferation and EMT while stimulating apoptosis. This work discloses the p53-activating agent SLMP53-2 which has promising therapeutic potential in advanced melanoma, either as a single agent or in combination therapy. By targeting p53, SLMP53-2 may counteract major features of melanoma aggressiveness.

LncRNA SAMMSON Mediates Adaptive Resistance to RAF Inhibition in BRAF-Mutant Melanoma Cells.

The long noncoding RNA (lncRNA) SAMMSON is required for human melanoma cell growth and survival. However, whether SAMMSON regulates the response of mutant BRAF melanoma cells to RAF inhibitors remains unknown. In this work, we showed that SAMMSON is rapidly induced upon inhibition of ERK signaling, and SAMMSON overexpression conferred resistance to vemurafenib-induced cytotoxicity in melanoma cells. SOX10 mediated transcriptional induction of SAMMSON by vemurafenib, and SOX10 sumoylation at K55 was essential for this function. In addition, depletion of SAMMSON activated p53 signaling, which is dependent on the SAMMSON-interacting protein CARF. Depletion of SAMMSON sensitized mutant BRAF melanoma cells to RAF inhibitors in vitro and in vivo, while CARF knockdown reversed the enhanced sensitivity. In summary, these findings suggest that SAMMSON may function as a new mediator of adaptive resistance to RAF inhibitors in melanoma by modulating CARF-p53 signaling. SIGNIFICANCE: This study highlights the role of a SAMMSON/CARF/p53 signaling axis in modulating the adaptive resistance of mutant BRAF melanoma to RAF inhibitors.

The Paradoxical Behavior of microRNA-211 in Melanomas and Other Human Cancers.

Cancer initiation, progression, and metastasis leverage many regulatory agents, such as signaling molecules, transcription factors, and regulatory RNA molecules. Among these, regulatory non-coding RNAs have emerged as molecules that control multiple cancer types and their pathologic properties. The human microRNA-211 (MIR211) is one such molecule, which affects several cancer types, including melanoma, glioblastoma, lung adenocarcinomas, breast, ovarian, prostate, and colorectal carcinoma. Previous studies suggested that in certain tumors MIR211 acts as a tumor suppressor while in others it behaves as an oncogenic regulator. Here we summarize the known molecular genetic mechanisms that regulate MIR211 gene expression and molecular pathways that are in turn controlled by MIR211 itself. We discuss how cellular and epigenetic contexts modulate the biological effects of MIR211, which exhibit pleiotropic effects. For example, up-regulation of MIR211 expression down-regulates Warburg effect in melanoma tumor cells associated with an inhibition of the growth of human melanoma cells in vitro, and yet these conditions robustly increase tumor growth in xenografted mice. Signaling through the DUSP6-ERK5 pathway is modulated by MIR211 in BRAFV600E driven melanoma tumors, and this function is involved in the resistance of tumor cells to the BRAF inhibitor, Vemurafenib. We discuss several alternate but testable models, involving stochastic cell-to-cell expression heterogeneity due to multiple equilibria involving feedback circuits, intracellular communication, and genetic variation at miRNA target sties, to reconcile the paradoxical effects of MIR211 on tumorigenesis. Understanding the precise role of this miRNA is crucial to understanding the genetic basis of melanoma as well as the other cancer types where this regulatory molecule has important influences. We hope this review will inspire novel directions in this field.

Growth Hormone Upregulates Mediators of Melanoma Drug Efflux and Epithelial-to-Mesenchymal Transition In Vitro and In Vivo.

Simple SummaryGrowth hormone (GH) action is strongly implicated in the progression and therapy resistance in several types of solid tumors which overexpress the GH receptor (GHR). The aim of our study was to characterize the effects of GH and its downstream effector insulin-like growth factor 1 (IGF-1) on melanoma using in vitro and in vivo models. We confirmed an IGF-1-independent role of elevated circulating GH in upregulating key mechanisms of therapy resistance and malignancy with analyses conducted at the molecular and cellular level. We identified that GH upregulates key mechanisms of therapy resistance and metastases in melanoma tumors in an IGF-1 dependent and independent manner by upregulating multidrug efflux pumps and EMT transcription factors. Our study reveals that GH action renders an intrinsic drug resistance phenotype to the melanoma tumors—a clinically crucial property of GH verifiable in other human cancers with GHR expression.Growth hormone (GH) and the GH receptor (GHR) are expressed in a wide range of malignant tumors including melanoma. However, the effect of GH/insulin-like growth factor (IGF) on melanoma in vivo has not yet been elucidated. Here we assessed the physical and molecular effects of GH on mouse melanoma B16-F10 and human melanoma SK-MEL-30 cells in vitro. We then corroborated these observations with syngeneic B16-F10 tumors in two mouse lines with different levels of GH/IGF: bovine GH transgenic mice (bGH; high GH, high IGF-1) and GHR gene-disrupted or knockout mice (GHRKO; high GH, low IGF-1). In vitro, GH treatment enhanced mouse and human melanoma cell growth, drug retention and cell invasion. While the in vivo tumor size was unaffected in both bGH and GHRKO mouse lines, multiple drug-efflux pumps were up regulated. This intrinsic capacity of therapy resistance appears to be GH dependent. Additionally, epithelial-to-mesenchymal transition (EMT) gene transcription markers were significantly upregulated in vivo supporting our current and recent in vitro observations. These syngeneic mouse melanoma models of differential GH/IGF action can be valuable tools in screening for therapeutic options where lowering GH/IGF-1 action is important.

Abstract PR14: Defining isoform-specific roles for AKTs in BRAFV600E-driven melanoma

Abstract The PI3K/AKT pathway is frequently dysregulated in cutaneous melanoma and impacts both tumor aggression and resistance to BRAFV600E/K inhibitors. While current clinical approaches to AKT inhibition are severely limited by the toxicity of pan-AKT inhibitors, selective inhibition of individual AKT isoforms (AKT1, AKT2, or AKT3) remains an attractive, if yet unattainable, approach. A critical gap in our understanding concerns how the three highly homologous yet functionally distinct AKT isoforms contribute to melanomagenesis and treatment response. To address this question, we are employing RNAi and gene editing approaches to interrogate the effect of selective suppression or CRISPR/Cas9-mediated deletion of each isoform in vitro, as well as the impact of AKT isoform loss on 1) the growth of melanoma xenografts and 2) the development of spontaneous tumors in a melanoma-prone mouse model. In addition, we are interrogating tumor-promoting functions of AKT isoform-selective substrates recently identified in a phospho-proteomic screen of mouse fibroblasts, a system that allows us to identify downstream actionable targets that may mediate the effects of AKT isoforms in tumorigenesis. Broadly, we are focusing on the importance of AKTs in tumor cell growth, metastasis, and response to inhibitors of BRAFV600E/K or CDK4/6. We find that loss of AKT1 impacts growth of BRAF mutant human melanoma cells both in vitro and in vivo. Additionally, AKT1 appears to play an isoform-specific role in response to pharmacologic CDK4/6 inhibition, impacting transcriptional and morphologic changes typically associated with permanent cell cycle arrest. In contrast, loss of AKT2 has a minimal impact on melanoma cell growth or response to CDK4/6 inhibition, but severely limits the development of metastatic disease, potentially through a combination of impaired seeding at the metastatic site and defects in glycolysis. While AKT3 loss does not appreciably impact the above-mentioned cellular phenotypes, the protumorigenic role of AKT3 may involve activation of broadly-acting neutral proteases previously implicated in cell cycle progression, cell migration, and CDK5 regulation. Taken together, we provide evidence for distinct roles for AKT isoforms in several aspects of the tumorigenic process as well as response to current therapies. Future studies will focus on identification and targeting of the relevant downstream mediators of these phenotypes. This abstract is also being presented as Poster A16. Citation Format: Jaymes Farrell, Jodie Pietruska, Siobhan McRee, Philip Tsichlis, Philip Hinds. Defining isoform-specific roles for AKTs in BRAFV600E-driven melanoma [abstract]. In: Proceedings of the AACR Special Conference on Melanoma: From Biology to Target; 2019 Jan 15-18; Houston, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(19 Suppl):Abstract nr PR14.

Circular RNA has circ 0001591 promoted cell proliferation and metastasis of human melanoma via ROCK1/PI3K/AKT by targeting miR-431-5p.

Melanoma a common skin tumor induced by excessive hyperplasia of abnormal melanocyte. Circular RNAs (circRNAs) play critical roles in various diseases and presented as the prognostic markers of melanoma. The present study was designed to confirm the effect of circ 0001591 on human melanoma cell growth and to elucidate its mechanism. Patient with melanoma was obtained from Shaanxi Provincial People's Hospital. Cell viability of A2058 cell was detected by MTT assay. The expression of circ 0001591 in serum of patients with melanoma was increased. Up-regulation of circ 0001591 promoted cell growth and cell invasion, and reduced apoptotic rate of melanoma. Down-regulation of circ 0001591 reduced cell growth and cell invasion, and promoted apoptotic rate of melanoma.Up-regulation of circ 0001591 induced PI3 K and p-Akt protein expressions in melanoma through induction of ROCK1 by suppression of miR-431-5p. Over-expression of circ 0001591 suppressed PI3 K and p-Akt protein expressions via suppression of ROCK1 in melanoma by induction of miR-431-5p. MiR-431-5p reduced the effects of circ 0001591 down-regulation on cell growth of melanoma through PI3K/AKT signal pathway. ROCK1 reduced the effects of circ 0001591 on cell growth of melanoma through PI3K/AKT signal pathway. Our findings demonstrated that circ 0001591 inhibits the progression of human melanoma through ROCK1/PI3K/AKT signal pathway by targeting ROCK1 by miR-431-5p.

Cell Cycle Regulation by Berberine in Human Melanoma A375 Cells.

We studied the effects of berberine on the proliferation, apoptosis, and migration of skin melanoma A375 cells, as well as cell cycle-related miRNAs and their target genes, CDK1, CDK2, and cyclins D1 and A. The inhibitory effect of berberine on the growth of A375 cells was evaluated by MTT assay. Cell apoptosis was detected by trypan blue staining. Cell migration was assessed by the scratch test. Cell cycle phases were determined by flow cytometry. The levels of miRNA-582-5p and miRNA-188-5, and mRNA of their target genes encoding CDK1, CDK2, and cyclins D1 and A were measured by qRT-PCR. The expression of cell cycle-related proteins (CDK1, CDK2, and cyclins D1 and A) was determined by Western blotting. Berberine inhibited the proliferation of A375 cells in a time- and dose-dependent manner and significantly and dose-dependently enhanced cell apoptosis. Scratch assay showed an inhibitory effect of berberine on migration of A375 cells. Berberine in low concentrations (20 and 40 μM) caused cell cycle arrest in the S and G2/M phases, while treatment with high concentrations of berberine (60 and 80 μM) arrested cell-cycle in the G2/M phase. The increase in berberine concentration led to an increase in miRNA-582-5p and miRNA-188-5p expression and a decrease in the expression of mRNA for the corresponding target genes encoding CDK1, CDK2, and cyclins D1 and A. Western blotting also revealed reduced expression of CDK1, CDK2, and cyclins D1 and A. Thus, berberine suppressed the growth and migration of human melanoma cells and promoted their apoptosis. Berberine can increase the expression of cell cycle-related miRNAs and cause degradation of the corresponding target genes, thereby blocking the cell cycle progression and inhibiting the melanoma A375 cells.