Human Melanoma Cell Lines Research Articles

Overexpression of c-MYC Promoter Binding Protein-1 Enhances Proliferation and Glucose Metabolism of Melanoma Cells Lines.

c-MYC promoter binding protein (MBP-1) is a product of alternatively translated mRNA encoding alpha-enolase (ENO1). In contrast to ENO1, MBP-1 possesses no enzymatic activity but acts as a transcriptional repressor of c-MYC. Ectopic over-expression of MBP-1 in tumor cells was shown to reduce cell proliferation and tumorigenicity, thus making it an attractive target for anticancer strategies. This study aimed to assess the effects of MBP-1 over-expression on human cutaneous melanoma cell lines. We overexpressed the full-length MBP-1 or its C-terminal truncated variant (MBP-1ΔC), in two human melanoma cell lines (A375, WM9) and assessed their subcellular localization. qPCR was then used to quantitate c-MYC transcription. Further, 5-ethynyl-2'-deoxyuridine incorporation assay was used to measure cell proliferation and a lactate assay was performed to measure the glycolysis rate of cells in normoxia and hypoxia. Finally, an in vitro wound-healing assay was performed to evaluate cell migration. The overexpressed MBP-1 variants predominantly localized in the cytoplasm and barely decreased c-MYC expression. Unexpectedly, the proliferation rate of MBP-1- transduced cells increased in comparison to controls, as did the rate of glucose metabolism in hypoxia. Furthermore, over-expression of MBP-1, but not MBP-1ΔC, led to a substantial decrease in the cell migration capacity of metastatic WM9 cells but not A375 cells from the primary tumor lesion. Misslocalization of over-expressed MBP-1 in the cytoplasm of two melanoma cell lines resulted in an unexpected tumor promoting activity by increasing cell proliferation and glycolysis rates in hypoxia.

Subsets of IFN Signaling Predict Response to Immune Checkpoint Blockade in Patients with Melanoma.

IFN signaling in the tumor microenvironment is a critical determinant of both response and resistance of cancer to immune checkpoint inhibitors (ICI). We hypothesized that distinct patterns of IFN signaling in melanoma are associated with clinical response or resistance to ICIs. Two tissue microarrays containing samples from 97 patients with metastatic melanoma who received nivolumab, pembrolizumab, or a combination of ipilimumab and nivolumab at Yale New Haven Hospital between 2011 and 2017 were randomized into discovery and validation cohorts. Samples were stained and visualized using multiplexed immunofluorescence microscopy for STAT1, STAT1 phosphorylated at Y701 (pSTAT1Y701), and PD-L1, and signals were quantified using the automated quantitative analysis method of quantitative immunofluorescence. Treatment response was assessed using RECIST, and overall survival was analyzed. For in vitro studies, human melanoma cell lines were stimulated with IFNγ and IFNβ, and Western blotting was performed. Pretreatment STAT1 levels were higher in responders to ICIs [complete response/partial response/stable disease (SD) for > 6 months] than in nonresponders (SD < 6 months/progressive disease). Higher pretreatment STAT1 levels were associated with improved survival after ICIs in both the discovery and validation cohorts. Western blot analysis of human melanoma cell lines stimulated with IFN demonstrated distinct patterns of upregulation of STAT1 compared with pSTAT1Y701 and PD-L1. When combining STAT1 and PD-L1 markers, patients with STAT1highPD-L1low tumors had improved survival compared with those with STAT1lowPD-L1high tumors. STAT1 may better predict melanoma response to ICIs than current strategies, and combined STAT1 and PD-L1 biomarkers may provide insight into IFN-responsive versus IFN-resistant states.

Determination of Common microRNA Biomarker Candidates in Stage IV Melanoma Patients and a Human Melanoma Cell Line: A Potential Anti-Melanoma Agent Screening Model.

MicroRNAs (miRNAs) are small, non-coding RNAs that play an important role in regulating gene expression. Dysregulation of miRNA expression is commonly observed in cancer, and it can contribute to malignant cell growth. Melanoma is the most fatal type of skin malignant neoplasia. Some microRNAs can be prospective biomarkers for melanoma in stage IV (advanced) at higher risk of relapses and require validation for diagnostic purposes. This work aimed to (1) determine the most significant microRNA biomarker candidates in melanoma using content analysis of the scientific literature, (2) to show microRNA biomarker candidates' diagnostic efficacy between melanoma patients and healthy control groups in a small-scale preliminary study by blood plasma PCR analysis, (3) to determine significant microRNA markers of the MelCher human melanoma cell line, which are also detected in patients with melanoma, that can be used as markers of drug anti-melanoma activity, and (4) test anti-melanoma activity of humic substances and chitosan by their ability to reduce level of marker microRNAs. The content analysis of the scientific literature showed that hsa-miR-149-3p, hsa-miR-150-5p, hsa-miR-193a-3p, hsa-miR-21-5p, and hsa-miR-155-5p are promising microRNA biomarker candidates for diagnosing melanoma. Estimating microRNA in plasma samples showed that hsa-miR-150-5p and hsa-miR-155-5p may have a diagnostic value for melanoma in stage IV (advanced). When comparing ΔCt hsa-miR-150-5p and ΔCt hsa-miR-155-5p levels in melanoma patients and healthy donors, statistically significant differences were found (p = 0.001 and p = 0.001 respectively). Rates ΔCt were significantly higher among melanoma patients (medians concerning the reference gene miR-320a were 1.63 (1.435; 2.975) and 6.345 (4.45; 6.98), respectively). Therefore, they persist only in plasma from the melanoma patients group but not in the healthy donors group. In human wild-type stage IV melanoma (MelCher) cell culture, the presence of hsa-miR-150-5p and hsa-miR-155-5p in supernatant was detected. The ability of humic substance fractions and chitosan to reduce levels of hsa-miR-150-5p and hsa-miR-155-5p was tested on MelCher cultures, which is associated with anti-melanoma activity. It was found that the hymatomelanic acid (HMA) fraction and its subfraction UPLC-HMA statistically significantly reduced the expression of miR-150-5p and miR-155-5p (p ≤ 0.05). For the humic acid (HA) fraction, this activity was determined only to reduce miR-155-5p (p ≤ 0.05). Ability to reduce miR-150-5p and miR-155-5p expression on MelCher cultures was not determined for chitosan fractions with a molecular weight of 10 kDa, 120 kDa, or 500 kDa. Anti-melanoma activity was also determined in the MTT test on MelCher cultures for explored substances. The median toxic concentration (TC50) was determined for HA, HMA and UPLC-HMA (39.3, 39.7 and 52.0 μg/mL, respectively). For 10 kDa, 120 kDa, or 500 kDa chitosan fractions TC50 was much higher compared to humic substances (508.9, 6615.9, 11352.3 μg/mL, respectively). Thus, our pilot study identified significant microRNAs for testing the in vitro anti-melanoma activity of promising drugs and melanoma diagnostics in patients. Using human melanoma cell cultures gives opportunities to test new drugs on a culture that has a microRNA profile similar to that of patients with melanoma, unlike, for example, murine melanoma cell cultures. It is necessary to conduct further studies with a large number of volunteers, which will make it possible to correlate the profile of individual microRNAs with specific patient data, including the correlation of the microRNA profile with the stage of melanoma.

Gene Expression Changes in Cytokine and Chemokine Receptors in Association with Melanoma Liver Metastasis.

Cytokines and chemokines (chemotactic cytokines) are soluble extracellular proteins that bind to specific receptors and play an integral role in the cell-to-cell signaling network. In addition, they can promote the homing of cancer cells into different organs. We investigated the potential relationship between human hepatic sinusoidal endothelial cells (HHSECs) and several melanoma cell lines for the expression of chemokine and cytokine ligands and receptor expression during the invasion of melanoma cells. In order to identify differences in gene expression related to invasion, we selected invasive and non-invasive subpopulations of cells after co-culturing with HHSECs and identified the gene expression patterns of 88 chemokine/cytokine receptors in all cell lines. Cell lines with stable invasiveness and cell lines with increased invasiveness displayed distinct profiles of receptor genes. Cell lines with increased invasive capacity after culturing with conditioned medium showed a set of receptor genes (CXCR1, IL1RL1, IL1RN, IL3RA, IL8RA, IL11RA, IL15RA, IL17RC, and IL17RD) with significantly different expressions. It is very important to emphasize that we detected significantly higher IL11RA gene expression in primary melanoma tissues with liver metastasis as well, compared to those without metastasis. In addition, we assessed protein expression in endothelial cells before and after co-culturing them with melanoma cell lines by applying chemokine and cytokine proteome arrays. This analysis revealed 15 differentially expressed proteins (including CD31, VCAM-1, ANGPT2, CXCL8, and CCL20) in the hepatic endothelial cells after co-culture with melanoma cells. Our results clearly indicate the interaction between liver endothelial and melanoma cells. Furthermore, we assume that overexpression of the IL11RA gene may play a key role in organ-specific metastasis of primary melanoma cells to the liver.

Expanding Opportunities in Viral Oncolysis.

Expanding Opportunities in Viral Oncolysis.

Isolation and identification of novel selective antitumor constituents, sidrin and sidroside, from Zizyphus spina-christi

BackgroundThe leaves of Zizyphus spina-christi (L.) Willd contain several compounds exhibiting different pharmacologic activities. However, studies on the cytotoxic activity of these compounds are limited. ObjectivesWe aimed to investigate and isolate cytotoxic compounds with selective antitumor effects from the leaves of Z. spina-christi using bioassay-guided fractionation of methanol extract. MethodsPowdered, dried leaves were subjected to methanol extraction and fractionated using n-hexane, chloroform, ethyl acetate, and n-butanol. Fractions with positive cytotoxicity against HeLa and THP-1 cell lines were further fractionated and eluted using various concentrations of organic solvents. Active compounds were isolated using different chromatographic methods and their chemical structures were determined using extensive spectroscopic methods, such as 1D NMR (1H NMR, 13C NMR, and DEPT), 2D NMR (COSY, HMBC, and HMQC), HRFAB-MS, and IR. Furthermore, the cytotoxic effects of the isolated compounds were evaluated against 62 tumor cell lines (including HeLa and THP-1) in addition to normal bone marrow cells. ResultsThe chloroform and aqueous methanol fractions of the leaves showed cytotoxic activity. Two compounds were successfully isolated and named “sidrin” (13-β-hydroxy-lup-20(30)-ene-2,3-β-epoxy-28-carboxylate) and “sidroside” (3-O-β-D-glucopyranosyl-(1–3)-α-L-arabinopyranosyl-jujubogenin-20-O-α-L-rhamnopyranoside). Sidrin exhibited cytotoxic activity against the human leukemia (Hl-60, RPMI-8226), lung cancer (A549, EKVX), breast cancer (BT-549, MDA-MB-231/ATCC), colon cancer (KM12), melanoma (M14, SK-MEL-5), and central nervous system (CNS) cancer (SF-295) cell lines, and selectivity was observed against the Hl-60, EKVX, BT-549, KM12, and SF-295 cell lines. In addition, sidrin was more active than sidroside and doxorubicin against the Hl-60 and EKVX cell lines. In contrast, sidrin had a similar effect to doxorubicin against the BT-549 and renal cancer (UO-31) cell lines. Sidroside was more selective against the leukemia (CCRF-CEM, MOLT-4), lung cancer (HOP-92, NCI-H322M), breast cancer (MDA-MB-468), melanoma (LOX IMVI), CNS cancer (SNB-19), ovarian cancer (OVCAR-8), renal cancer (UO-31, RXF 393), and prostate cancer (PC-3) cell lines. Both compounds exhibited similar activity against the breast cancer (MDA-MB-231, T-47D), colon cancer (HCC-2998, HCT-116), ovarian cancer (OVCAR-3), renal cancer (UO-31, 786–0, and SN 12C) cell lines. Normal bone marrow cells were unaffected at the same concentrations of sidrin and sidroside applied to tumor cells. ConclusionsThese results suggest tumor-selective cytotoxicity of sidrin and sidroside.

Synergy, Additivity and Antagonism between Esculetin and Six Commonly Used Chemotherapeutics in Various Malignant Melanoma Cell Lines-An Isobolographic Analysis.

(1) Malignant melanomas are dangerous skin cancers, and the treatment of melanomas with various cytostatic drugs often causes side effects and after their prolonged use resistance to these drugs appears. The aim of this study was to evaluate the anticancer effects of esculetin (a simple coumarin) and to assess pharmacodynamic interactions between esculetin and six commonly used cytostatic drugs (cisplatin, epirubicin, docetaxel, paclitaxel, mitoxantrone and vemurafenib) using an isobolographic analysis. (2) The experiments were carried out on four human malignant melanoma cell lines (FM55P, A375, FM55M2 and SK-MEL28). The effects of esculetin on viability, cell proliferation and cytotoxicity were verified in the range of concentrations of 2-200 μM. (3) Esculetin inhibited, in a dose-dependent manner, malignant melanoma cell viability and proliferation. The IC50 for esculetin ranged from 18.20 ± 2.93 to 120.64 ± 30.39 μM depending on the melanoma cell lines used. The combinations of esculetin with epirubicin and vemurafenib showed antagonistic interactions, the combinations of esculetin with cisplatin, docetaxel and paclitaxel showed additive interactions. For the combinations of esculetin with mitoxantrone, the isobolographic analysis displayed synergy. (4) In the treatment of malignant melanoma, esculetin should not be combined with epirubicin or vemurafenib, due to the reduction of their anticancer effects, while the synergistic interactions (esculetin + mitoxantrone) deserve a preclinical recommendation as a beneficial combination during anticancer therapy.

Comparison of Fucoidans from Saccharina latissima Regarding Age-Related Macular Degeneration Relevant Pathomechanisms in Retinal Pigment Epithelium.

Fucoidans from brown algae are described as anti-inflammatory, antioxidative, and antiangiogenic. We tested two Saccharina latissima fucoidans (SL-FRO and SL-NOR) regarding their potential biological effects against age-related macular degeneration (AMD). Primary porcine retinal pigment epithelium (RPE), human RPE cell line ARPE-19, and human uveal melanoma cell line OMM-1 were used. Cell survival was assessed in tetrazolium assay (MTT). Oxidative stress assays were induced with erastin or H2O2. Supernatants were harvested to assess secreted vascular endothelial growth factor A (VEGF-A) in ELISA. Barrier function was assessed by measurement of trans-epithelial electrical resistance (TEER). Protectin (CD59) and retinal pigment epithelium-specific 65 kDa protein (RPE65) were evaluated in western blot. Polymorphonuclear elastase and complement inhibition assays were performed. Phagocytosis of photoreceptor outer segments was tested in a fluorescence assay. Secretion and expression of proinflammatory cytokines were assessed with ELISA and real-time PCR. Fucoidans were chemically analyzed. Neither toxic nor antioxidative effects were detected in ARPE-19 or OMM-1. Interleukin 8 gene expression was slightly reduced by SL-NOR but induced by SL-FRO in RPE. VEGF secretion was reduced in ARPE-19 by SL-FRO and in RPE by both fucoidans. Polyinosinic:polycytidylic acid induced interleukin 6 and interleukin 8 secretion was reduced by both fucoidans in RPE. CD59 expression was positively influenced by fucoidans, and they exhibited a complement and elastase inhibitory effect in cell-free assay. RPE65 expression was reduced by SL-NOR in RPE. Barrier function of RPE was transiently reduced. Phagocytosis ability was slightly reduced by both fucoidans in primary RPE but not in ARPE-19. Fucoidans from Saccharina latissima, especially SL-FRO, are promising agents against AMD, as they reduce angiogenic cytokines and show anti-inflammatory and complement inhibiting properties; however, potential effects on gene expression and RPE functions need to be considered for further research.

Cytotoxicity of Carbon Nanotubes, Graphene, Fullerenes, and Dots.

The cytotoxicity of carbon nanomaterials is a very important issue for microorganisms, animals, and humans. Here, we discuss the issues of cytotoxicity of carbon nanomaterials, carbon nanotubes, graphene, fullerene, and dots. Cytotoxicity issues, such as cell viability and drug release, are considered. The main part of the review is dedicated to important cell viability issues. They are presented for A549 human melanoma, E. coli, osteosarcoma, U2-OS, SAOS-2, MG63, U87, and U118 cell lines. Then, important drug release issues are discussed. Bioimaging results are shown here to illustrate the use of carbon derivatives as markers in any type of imaging used in vivo/in vitro. Finally, perspectives of the field are presented. The important issue is single-cell viability. It can allow a correlation of the functionality of organelles of single cells with the development of cancer. Such organelles are mitochondria, nuclei, vacuoles, and reticulum. It allows for finding biochemical evidence of cancer prevention in single cells. The development of investigation methods for single-cell level detection of viability stimulates the cytotoxicity investigative field. The development of single-cell microscopy is needed to improve the resolution and accuracy of investigations. The importance of cytotoxicity is drug release. It is important to control the amount of drug that is released. This is performed with pH, temperature, and electric stimulation. Further development of drug loading and bioimaging is important to decrease the cytotoxicity of carbon nanomaterials. We hope that this review is useful for researchers from all disciplines across the world.

ALOX5 promotes autophagy-dependent ferroptosis by activating the AMPK/mTOR pathway in melanoma

BackgroundMelanoma has become more common, and its therapeutic management has remained challenging in recent decades. The purpose of our study is to explore new prognostic therapeutic markers of melanoma and to find new therapeutic methods and therapeutic targets of novel drugs, which have great significance. MethodFirst, the arachidonate 5-lipoxygenase (ALOX5) gene associated with both autophagy and ferroptosis was identified by R version 4.2.0. We used human melanoma and para-cancer tissues, human melanoma cell lines, and melanoma-bearing mouse tissues. We used qRT–PCR, Western blotting, immunohistochemistry, immunofluorescence staining, CCK-8, iron ion assay, GSH assay, and MDA assay. In vivo, the ferroptosis activation and antitumor effects of recombinant human ALOX5 protein were evaluated using a xenograft model. ResultWe report that the downregulation of ALOX5 in melanoma is positively correlated with the prognosis of patients and is an independent prognostic factor. Elevated ALOX5 contributes to autophagy and ferroptosis in vitro and in vivo. At the same time, inhibition of autophagy can reduce ferroptosis enhanced by ALOX5, and autophagy and ALOX5 have a synergistic effect. The results of the mechanistic study showed that the increase in ALOX5 could activate the AMPK/mTOR pathway and inhibit GPX4 expression, promoting the occurrence of autophagy-dependent ferroptosis, while the decrease in p-AMPK/AMPK inhibited the occurrence of ferroptosis. ConclusionALOX5 deficiency was resistant to autophagy and ferroptosis by inhibiting the AMPK/mTOR pathway. Therefore, it can provide new targets and methods for melanoma drug development.

1249 Research of hiperfect-mediated RNA interference targeting hTERT on the biological behavior of the human malignant melanoma cell line A375

1249 Research of hiperfect-mediated RNA interference targeting hTERT on the biological behavior of the human malignant melanoma cell line A375

Determination of Some Isoquinoline Alkaloids in Extracts Obtained from Selected Plants of the Ranunculaceae, Papaveraceae and Fumarioideae Families by Liquid Chromatography and In Vitro and In Vivo Investigations of Their Cytotoxic Activity.

Alkaloids are heterocyclic bases with widespread occurrence in nature. Plants are rich and easily accessible sources of them. Most isoquinoline alkaloids have cytotoxic activity for different types of cancer, including malignant melanoma, the most aggressive type of skin cancer. The morbidity of melanoma has increased worldwide every year. For that reason, developing new candidates for anti-melanoma drugs is highly needed. The aim of this study was to investigate the alkaloid compositions of plant extracts obtained from Macleaya cordata root, stem and leaves, Pseudofumaria lutea root and herb, Lamprocapnos spectabilis root and herb, Fumaria officinalis whole plant, Thalictrum foetidum root and herb, and Meconopsis cambrica root and herb by HPLC-DAD and LC-MS/MS. For determination of cytotoxic properties, human malignant melanoma cell line A375, human Caucasian malignant melanoma cell line G-361, and human malignant melanoma cell line SK-MEL-3 were exposed in vitro to the tested plant extracts. Based on the in vitro experiments, Lamprocapnos spectabilis herb extract was selected for further, in vivo research. The toxicity of the extract obtained from Lamprocapnos spectabilis herb was tested using an animal zebrafish model in the fish embryo toxicity test (FET) for determination of the LC50 value and non-toxic doses. Determination of the influence of the investigated extract on the number of cancer cells in a living organism was performed using a zebrafish xenograft model. Determination of the contents of selected alkaloids in different plant extracts was performed using high performance liquid chromatography (HPLC) in a reverse-phase system (RP) on a Polar RP column with a mobile phase containing acetonitrile, water and ionic liquid. The presence of these alkaloids in plant extracts was confirmed by LC-MS/MS. Preliminary cytotoxic activity of all prepared plant extracts and selected alkaloid standards was examined using human skin cancer cell lines A375, G-361, and SK-MEL-3. The cytotoxicity of the investigated extract was determined in vitro by cell viability assays (MTT). For in vivo determination of investigated extract cytotoxicity, a Danio rerio larvae xenograft model was used. All investigated plant extracts in in vitro experiments exhibited high cytotoxic activity against the tested cancer cell lines. The results obtained using the Danio rerio larvae xenograft model confirmed the anticancer activity of the extract obtained from Lamprocapnos spectabilis herb. The conducted research provides a basis for future investigations of these plant extracts for potential use in the treatment of malignant melanoma.

Abstract LB017: Potential role of kinesin family member C1 (KIFC1) in melanoma

Abstract According to the Surveillance, Epidemiology, and End Results (SEER) analyses, based on 2017-2019 data, approximately ~2.1 percent of men and women will be diagnosed with melanoma at some point during their lifetime. Melanoma can be fatal if not surgically removed at an early stage, with the 5-year survival being a dismal 29.8% for a stage IV melanoma. Melanoma mortality is primarily due to the distant organ metastases and its resistance to treatment, even with newly developed immunotherapy and/or targeted therapies (BRAF and MEK inhibitors). Thus, the discovery of novel melanoma targets is crucial as they may be able to provide alternative treatment options or be used alone or in combination with current therapies. KIFC1 (kinesin family member C1; also known as HSET, an ortholog in Drosophila melanogaster), a nonessential kinesin motor protein, has an established role in centrosome clustering which is utilized by cancer cells to evade apoptosis and mitotic arrest. This occurs when replicating cells harbor additional centrosomes, a hallmark of cancer. The requirement of KIFC1 in mitosis of cancer cells harboring abnormal centrosomes, but not that of normal cells, makes it a potential drug target for cancer management. The goal of this study was to determine the role and significance of KIFC1 in melanoma. Differential expression analysis of GTEX and TCGA RNA-seq data identified significantly higher levels of KIFC1 in both primary and metastatic melanoma as compared to normal skin. In addition, higher expression of KIFC1 was found to be associated with poorer overall survival of melanoma patients. Furthermore, a quantitative protein estimation with the automated ProteinSimple Jess capillary western blotting system demonstrated higher KIFC1 expression in several melanoma cell lines when compared to normal melanocytes. In addition, we also found significantly increased expression of KIFC1 mRNA in mouse melanoma tumors obtained from the genetically engineered BrafV600E/PtenNULL mice, as compared to the normal skin. Next, we determined the effect of a small molecule KIFC1 inhibitor, AZ82 on A375, G361 and Hs294T melanoma cells. AZ82 is an ATP-competitive inhibitor that binds the KIFC1-microtubule complex, blocking the release of ADP and negating its role as a motor protein. Employing RealTime-Glo MT cell viability assay as well as the endpoint XTT growth assay, we found that AZ82 treatment resulted in a significant growth inhibition of human melanoma cells at 2-3.5 µM concentrations. Additionally, AZ82 treatments resulted in a significant decrease in clonogenic survival in all three human melanoma cell lines. Collectively, our data suggests a potential role of KIFC1 in melanoma progression, and merits further investigation to determine the roles and functional and therapeutic significance of KIFC1 in melanoma. Citation Format: Davis S. Mau, Mary A. Ndiaye, Gabriella R. Zaemisch, Chandra K. Singh, Jess Vera, Sean R. McIlwain, Nihal Ahmad. Potential role of kinesin family member C1 (KIFC1) in melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB017.

Metastatic Melanoma: A Preclinical Model Standardization and Development of a Chitosan-Coated Nanoemulsion Containing Temozolomide to Treat Brain Metastasis.

Melanoma is the most aggressive type of skin cancer. Brain metastasis is the worst scenario in metastatic melanoma and the treatment options for these patients are limited. Temozolomide (TMZ) is a chemotherapy agent used to treat primary central nervous system tumors. Our objective was to develop chitosan-coated nanoemulsion containing temozolomide (CNE-TMZ) for nasal route administration to melanoma brain metastasis treatment. A preclinical model of metastatic brain melanoma was standardized, and the efficiency of the developed formulation was further determined in vitro and in vivo. The nanoemulsion was done by spontaneous emulsification method and the formulation was characterized by size, pH, polydispersity index, and zeta potential. Culture assessments to determine cell viability were done in the A375 human melanoma cell line. To determine the safety of formulation, healthy C57/BL6 mice were treated with a nanoemulsion without TMZ. The model in vivo used B16-F10 cells implanted by stereotaxic surgery in C57/BL6 mice brains. The results demonstrate that the preclinical model used showed to be useful to analyze the efficiency of new candidate drugs to treat melanoma brain metastasis. The chitosan-coated nanoemulsions with TMZ showed the expected physicochemical characteristics and demonstrated safety and efficacy, reducing around 70% the tumor size compared to control mice, and presenting a tendency in mitotic index reduction, becoming an interesting approach to treat melanoma brain metastasis.

Abstract 2536: Intracellular Ctla4 overexpression promotes melanoma progression and metastasis

Abstract Cytotoxic T Lymphocyte Antigen 4 (CTLA4) expressed on the surface of T cells is an important immunotherapeutic target in many cancers, including melanoma. However, we previously found highly upregulated expression of CTLA4 in BRAF/NRAS-mutant human melanoma cell lines and tissues. Although CTLA4 is almost entirely expressed intracellularly in melanoma cells, its intracellular functions have remained elusive. Ectopic expression of Ctla4 (Ctla4-ee) in mouse melanoma cell lines significantly promoted lung colonization in syngeneic mice as well as in immunocompromised mice, suggesting that Ctla4 had pro-tumorigenic effects independent of its extracellular immune checkpoint function. Proteomics analysis identified apoptosis to be a major affected pathway and we found that Ctla4 ectopic-expressing mouse melanoma cells (B2905-Ctla4-ee) were significantly resistant to doxorubicin-induced apoptosis as compared to empty vector (EV) controls. In a reciprocal experiment, knocking out CTLA4 in the Hs936T human melanoma cells, that exhibit high endogenous CTLA4 expression, showed significantly increased apoptosis than the parental cells. Moreover, significant upregulation of anti-apoptotic proteins (Bnip3, Birc6, Pak1, Mcl-1, Survivin, Rac1/Cdc42, Bcl-2, and Bnip3l) and downregulation of pro-apoptotic proteins (p53 and Bad) were observed in CTLA4-ee cells as compared to EV controls. CTLA4-ee cells also showed significantly higher invasion in Matrigel-coated Transwell assay. Interestingly, we also found that CTLA4 translocated to mitochondria, where it downregulated oxidative phosphorylation and increased glycolysis. These findings lead us to hypothesize that CTLA4 plays a significant role in regulating apoptosis and mitochondrial metabolic functions, leading to the promotion of melanoma progression and metastasis. Citation Format: Hasan Raza Kazmi, Xuan Mo, Bo Zhou, Sarah Preston Alp, Scott Gross, Hassaan Wajeeh, Carmen Merali, John Elrod, Jonathan Soboloff, Salim Merali, M. Raza Zaidi. Intracellular Ctla4 overexpression promotes melanoma progression and metastasis [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 2536.

Abstract 538: Inhibition of progression of malignant melanomas in B16F10 murine model by mecombinant N-acetylgalactosamine-4-Sulfatase (arylsulfatase B)

Abstract Introduction: Lower expression and activity of N-acetylgalactosamine-4-sulfatase (Arylsulfatase B; ARSB) were inversely associated with increased invasiveness in seven human melanoma cell lines (Oncotarget 2017, 8(3):4169-4180). The decline in ARSB occurred as chondroitin 4-sulfate, a substrate of ARSB, increased. Also, expression of CSPG4 (chondroitin sulfate proteoglycan 4), pro-MMP (matrix metalloproteinase)-2, and PD-L1 (programmed death-ligand 1) increased, as ARSB declined. In vitro exposure of malignant melanoma cells to exogenous recombinant human (rh)ARSB (R&amp;D Systems, Bio-Techne), reduced invasiveness and reduced BrdU incorporation of the malignant melanoma cells. Experiment: To further assess the impact of exogenous ARSB on progression of melanoma, the progression of subcutaneous B16F10 murine melanomas was tested with rhARSB. Following subcutaneous (SC) injection of 250,000 B16F10 cells (ATCC) in the right flank of 9-10-week-old female mice, control (n=12) and treated mice (n=28) were observed for up to 30 days. Doses of ARSB ranged from 0.1-0.4 mg/kg administered SC at the tumor site on days 2,7,14, and 21 or, alternatively in one group, administered on days 2,7,11,15, and 19, following tumor cell injection. Summary of Data: Survival was significantly increased, and tumor growth rate and tumor volume were significantly reduced in the treated mice (p&amp;lt;0.001). The dose of 0.2 mg/kg was superior to 0.1 mg/kg, but the effect of further dose increase or of increase in treatment frequency was marginal. Mean tumor volume in control mice was 1.41 ± 0.78 cm3 on day 14 post tumor injection and 3.06 ± 1.09 cm3 on day 17, compared to 0.27 ± 0.18 cm3 on day 14 and 0.37 ± 0.09 cm3 on day 17 in mice treated by 0.2 mg/kg ARSB on days 2,7, and 14. Six control mice died by day 18 post-tumor injection, in contrast to no deaths in treated mice by day 18. Three mice treated with ARSB had no palpable tumor when euthanized. In the untreated mice with tumors, chondroitin sulfate tumor content was 12.02 ± 0.84 µg/mg protein, compared to 8.10 ± 0.61 µg/mg protein in the treated mice. Expression of PD-L1 declined to &amp;lt;35% of the untreated tumor level in the treated mice, and tumor PD-L1 declined to 575 ± 182 pg/mg protein, compared to untreated tumor value of 1225 ± 273 pg/mg protein. Expression of CHST (carbohydrate sulfotransferase) 15, pro-MMP2, and CSPG4 all declined following exogenous ARSB. In contrast, CHST11 expression increased to 1.85 times the control level. No metastases were evident in either untreated or treated mice. Conclusion: Treatment with exogenous recombinant ARSB reduced tumor progression and improved survival in the subcutaneous murine B16F10 malignant melanoma model. ARSB acts as a tumor suppressor gene and impacts on expression of critical genes associated with melanoma, including PD-L1, CSPG4, and pro-MMP2. Citation Format: Joanne Kramer Tobacman, Insug O-Sullivan, Sumit Bhattacharyya. Inhibition of progression of malignant melanomas in B16F10 murine model by mecombinant N-acetylgalactosamine-4-Sulfatase (arylsulfatase B) [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 538.

Abstract 1256: Transglutaminase-2 is elevated in the invasive cell state and modulates the tumor immune microenvironment in cutaneous melanoma

Abstract Cutaneous melanoma is the most fatal skin cancer; resistance to targeted therapies contributes to poor prognosis. In some cases, resistance arises from pre-existing tumor heterogeneity, which allows subpopulations of drug-tolerant cells with distinct transcriptional states to survive in the presence of drug. The loss of SOX10, a lineage-specific transcription factor, is known to drive melanoma phenotype switching from a proliferative to an invasive drug-tolerant state. Here, we found that knocking out SOX10 in human and mouse melanoma cell lines leads to the upregulation of transglutaminase-2 (TGM2), a calcium-dependent cross-linking enzyme. Analysis of publicly available bulk and single-cell RNA-sequencing data showed that TGM2 is highly expressed in the invasive cell state in melanoma cell lines and patient-derived melanoma cultures, respectively. Furthermore, knockdown of SOX10 in patient-derived melanoma cultures increases TGM2 mRNA expression. 3D spheroid assays and extracellular matrix production/remodeling assays showed that knockdown of TGM2 has no effect on the invasiveness of SOX10-deficient cells. However, we found that TGM2 is secreted by SOX10-deficient cells and hypothesized that it could modulate the tumor immune microenvironment (TIME) given that TGM2 has been associated with increased immune infiltration in melanoma patient samples. To investigate the effect of TGM2 on the TIME, we stably overexpressed TGM2/Tgm2 in syngeneic mouse melanoma cell lines and allowed tumors to grow in immune-competent C57BL/6 mice. As compared to empty vector, TGM2/Tgm2-overexpression led to an increase in the percentage and number of CD4+ T cells and B cells, and a decrease in the number of myeloid cells, in the tumor immune compartment by flow cytometry analysis. Future studies will assess which subsets of CD4+ T cells and B cells infiltrate TGM2/Tgm2-overexpressing tumors, how these changes to the TIME affect melanoma invasiveness, and if TGM2 expression affects response to targeted therapy in vivo. Overall, our data suggest that TGM2 is highly expressed in the invasive melanoma cell state, is regulated by the SOX10 transcription factor, and can modulate adaptive immune cells in the TIME. Citation Format: Signe Caksa, Nicole A. Wilski, Erica L. Kitterman, McKenna Q. Glasheen, Jacob S. Heilizer, Timothy J. Purwin, Claudia Capparelli, Andrew E. Aplin. Transglutaminase-2 is elevated in the invasive cell state and modulates the tumor immune microenvironment in cutaneous melanoma [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 1256.

Abstract 4451: Developing a PROTAC-based NR4A1 degrader for melanoma cancer therapy

Abstract Introduction: Melanoma originates from melanocytes within the epidermis and is one of the most common cancers, with nearly 100000, new cases yearly. Despite numerous advancements in therapies to treat melanoma, a prevalent population of patients still do not respond to currently approved therapies. Recent studies have highlighted the role of transcription factor nuclear receptor subfamily 4 group A member 1 (NR4A1) in melanoma for cancer survival, invasion, and metastasis. NR4A1 is also involved in glucose metabolism. Our project aims to identify an effective degrader of NR4A1 using a PROTAC strategy and then validate its effectiveness in reducing the growth of melanoma. PROTACs consists of three domains: a warhead that binds to the protein of interest, a ligand to an E3 ligase, and a linker that brings both domains in proximity to one another. The PROTAC can recruit an E3 ligase to ubiquitinate NR4A1 and degrade it via the ubiquitin-proteasome system (UPS). Results: Our first goal was to identify valid PROTAC candidates that can effectively degrade NR4A1. We identified NR-V04, which demonstrated a dose-dependent degradation of NR4A1 in various melanoma cell lines. We further investigated time-dependent degradation, and NR-V04 was able to achieve in vitro degradation of NR4A1 16 hours after treatment. Additionally, we validated the mechanism of degradation via the UPS through various models. NR-V04 treatment of cells with a VHL knockout, which removes the E3 ligase recruited, experienced no degradation of NR4A1, and treatment of cells treated with MG132, a proteasome inhibitor, also showed no degradation. We observed degradation in vitro of numerous mouse and human cell lines. To investigate the cancer-killing effects of NR-V04, we completed MTS assays on the human melanoma cell lines CHL1 and A375, which showed an EC50 of 0.723 μM and 1.025 μM, respectively. When comparing NR-V04 treated and untreated CHL1 cells, NR-V04 was able to significantly decrease melanoma cell viability. NR4A1 knockout in CHL1 also showed decreased melanoma cell viability, and when comparing NR-V04 treated and untreated in NR4A1 knockout, there was no further decrease in melanoma cell viability. As for in vivo models, NR4A1 knockout in CHL1 and A375 exhibited slower tumor growth compared to the wild type. Furthermore, NR-V04 showed suppression of CHL1 and A375 tumor-bearing NSG mice melanoma growth at low dose concentrations of 1 mg/kg after seven days compared to vehicle and warhead treatment. Western blot analysis of tumor tissue provides support for the ability of NR-V04 to degrade tumor-intrinsic NR4A1. Conclusion: NR-V04 can selectively degrade NR4A1, in vitro and in vivo, to decrease melanoma cancer cell viability via the UPS. NR-V04 holds promising therapeutic potential as a cancer therapy for patients with melanoma. Citation Format: Rohan Master, Yuewan Luo, Yufeng Xiao, Daohong Zhou, Lei Wang, Guangrong Zheng, Weizhou Zhang. Developing a PROTAC-based NR4A1 degrader for melanoma cancer therapy. [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 4451.

Abstract 466: A potential pro-oncogenic role of SERPINB4 in melanoma

Abstract Despite recent therapeutic advancements, melanoma remains one of the deadliest forms of skin cancer. Melanoma metastasis and recurrence is associated with the existence of heterogeneous cell populations within tumors that have the ability to both initiate metastatic programs and bypass immune recognition. Tumor cells achieve immune evasion by interfering with immune signaling to limit immune cell infiltration, allowing tumor cell proliferation and growth. SERPINB4 (Squamous Cell Carcinoma Antigen 2 or SCCA2), a serine protease inhibitor, has been shown to regulate the host immune response against tumor cells by inhibiting immune cell activity. Interestingly, certain cancer cell types have been reported to overexpress SERPINB4. However, the expression profile and the functional significance of SERPINB4 in melanoma is not known. In this study, employing ‘The Cancer Genome Atlas’ (TCGA), we found that SERPINB4 is overexpressed and significantly associated with lower overall survival in patients with melanoma. Next, employing a panel of human melanoma cell lines, we demonstrated that SERPINB4 is overexpressed in melanoma cells when compared to normal human melanocytes. In addition, CRISPR knockout of SERPINB4 in high-SERPINB4-expressing A375 melanoma cells resulted in a significant decrease in proliferation of melanoma cells in comparison to control cells. Conversely, forced overexpression of SERPINB4 in low-SERPINB4-expressing SK-MEL-2 and SK-MEL-28 melanoma cells significantly increased melanoma cell proliferation. Moreover, RT-qPCR analyses suggested that SERPINB4 overexpression significantly increased, while its knockout significantly decreased epithelial-mesenchymal transition (EMT) markers (N-cadherin, β-catenin, Snail and Zeb1) in melanoma cells. Additionally, SERPINB4 manipulation significantly modulated the expression of genes involved in antigen-presentation (MHC Class I molecules, HLA-A, -B, and -C) in melanoma cells. Taken together, our data suggested a potential oncogenic role of SERPINB4 in melanoma. Our study also suggested that SERPINB4 might be a promising therapeutic target for melanoma. Indeed, additional in vitro mechanistic and in vivo studies are needed to firmly establish the mechanism and therapeutic potential of SERPINB4 for melanoma management. Citation Format: Gagan Chhabra, Carl A. Shirley, Rachel K. Robarge, Hassan A. Rizvi, Mary A. Ndiaye, Nihal Ahmad. A potential pro-oncogenic role of SERPINB4 in melanoma [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 466.

Abstract 3602: The metastasis-suppressive function of intracellular galectin-3 in melanoma

Abstract Melanoma is a relatively rare skin cancer. However, it accounts for most of all skin cancer-related deaths worldwide. Once melanoma spreads to distant sites, it confers a poor prognosis characterized by resistance to therapy and high mortality rate. Hence, a favorable clinical outcome is strongly correlated with early diagnosis. Despite the ongoing research to identify novel diagnostic, prognostic, and therapeutic targets for metastatic melanoma (MM), a reliable serum marker to predict whether melanoma is vulnerable to metastasize or has already metastasized is still lacking. Galectin-3 (Gal-3), a ß-galactoside-binding protein, is widely expressed by many human epithelial and immune cells. High extracellular Gal-3 expression levels have been reported to be positively correlated with late-stage disease in melanoma patients, where it is theorized to bind surface glycosylated proteins to promote melanoma cell invasion and metastasis. Gal-3 is also expressed intracellularly where it participates in the regulation of many biological processes. However, intrinsic Gal-3 levels within the melanoma cell and its relationship to melanoma progression is still poorly understood. Using The Cancer Genome Atlas (TCGA) database, we analyzed the Gal-3 expression profiles of 471 tumor samples obtained from melanoma patients. To our surprise, TCGA data analysis has shown significantly higher expression of Gal-3 in primary melanoma samples compared to metastatic melanoma. We hypothesize that intracellular Gal-3 potentially negatively regulates primary melanoma progression to metastatic disease. Using several human melanoma cell lines silenced for Gal-3 expression, we investigated the corresponding malignancy-associated activities of these cells. Our results revealed that Gal-3 silencing in melanoma cells potentiated melanoma migration, invasion, and colony formation, compared with mock controls, suggesting that intracellular Gal-3 could interfere with melanoma metastatic activity. Moreover, loss of Gal-3 boosted the activation of the PI3K/AKT and MAPK signaling pathways and upregulated nuclear factor of activated T cells (NFAT1) expression and its pro-metastatic downstream target genes. Importantly, this study illuminates the apparent opposing roles of Gal-3 in melanoma progression, with intracellular Gal-3 potentially serving as a metastasis-suppressive molecule. Moreover, these studies reveal the potential of analyzing melanoma cell-intrinsic levels of Gal-3 to better predict metastatic potential and clinical outcome in melanoma patients. Citation Format: Norhan B. B. Mohammed, Charles J. Dimitroff. The metastasis-suppressive function of intracellular galectin-3 in melanoma. [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 3602.