Proliferation Of Human Melanoma Cells Research Articles

MiR-942-5p promotes the proliferation and invasion of human melanoma cells by targeting DKK3

Objective The purpose of this study was to figure out the dysregulation of miR-942-5p in melanoma and its role in melanoma pathogenesis. Methods Quantitative real-time PCR (qRT-PCR) assay was used to determine the change of RNA expression. Protein expression was examined by Western blotting. miRNA target was validated through TargetScan and luciferase assay. Cell migration and invasion were detected by wound healing and transwell assay, respectively. Results Results of qRT-PCR manifested miR-942-5p were upregulated in melanoma cell. High expression of miR-942-5p in melanoma patients presented a poor prognosis. Upregulation of miR-942-5p accelerated cell proliferation, migration, and invasion in melanoma cells. Cell apoptosis was inhibited by miR-942-5p mimics. Suppression of miR-942-5p by its inhibitor showed the opposite effects in melanoma cells. TargetScan and luciferase assay showed that miR-942-5p directly targeted to the 3′-untranslated region (3′-UTR) of DKK3. Overexpression of DKK3 inhibited GSK-3β phosphorylation and reduced the expression of β-catenin in both cytoplasm and nucleus, which were induced by miR-942-5p mimics leading to the activation of Wnt/β-catenin pathway. Conclusion Upregulation of miR-942-5p was observed in melanoma cells and tissues and significantly associated with a poor prognosis. Though targeting 3′-UTR of DKK3, miR-942-5p could activate Wnt/β-catenin pathway, resulting in melanoma cell proliferation, migration, and invasion, which promoted the development of melanoma. These results showed that miR-942-5p might be a diagnosis and prognosis biomarker in melanoma.

Guizhi Fuling pills inhibit the proliferation, migration and invasion of human cutaneous malignant melanoma cells by regulating the molecular axis of LncRNA TPT1-AS1 / miR-671-5p

The current research was aimed to explore the effects of Guizhi Fuling Pills on the proliferation, migration and invasion of human cutaneous malignant melanoma cells and its regulation on the molecular axis of LncRNA TPT1-AS1 / miR-671-5p. Human cutaneous malignant melanoma cells A375 were cultured in vitro and randomly divided into Con group, Guizhi Fuling pills-L group, Guizhi Fuling pills-M group, Guizhi Fuling pills-H group, Guizhi Fuling pills-H + pcDNA group, Guizhi Poria pills-H + pcDNA-TPT1-AS1 group. MTT was used to detect cell proliferation. The Transwell cell test was used to detect cell migration and invasion. qRT-PCR was used to detect the expression of TPT1-AS1 and miR-671-5p. The dual-luciferase report experiment verified the targeting relationship of TPT1-AS1, miR-671-5p. Western blot was used to detect the expression of Ki-67, PCNA, MMP-2 and MMP-9. Compared with Con group, Guizhi Fuling Pills could inhibit cell proliferation, migration and invasion (p<0.05), and also inhibit the expression of Ki-67, PCNA, MMP-2, MMP-9, TPT1-AS1 (p<0.05), promote the expression of miR-671-5p (p<0.05)., and the differences between the indexes of Guizhi Fuling Pill-L group, Guizhi Fuling Pill-M group and Guizhi Fuling Pill-H group were statistically significant (p<0.05). The dual-luciferase report experiment confirmed that TPT1-AS1 could target and bind to miR-671-5p and could regulate the expression and activity of miR-671-5p. Overexpression of TPT1-AS1 could reduce the inhibitory effect of Guizhi Fuling Pills on proliferation, migration and invasion of A375 cells. Guizhi Fuling Pill may reduce the proliferation, migration and invasion of human cutaneous malignant melanoma cells by down-regulating the expression of TPT1-AS1 and up-regulating the expression of miR-671-5p.

沉默ATAD3A对黑素瘤A375细胞增殖、侵袭和迁移的影响及机制研究

沉默ATAD3A对黑素瘤A375细胞增殖、侵袭和迁移的影响及机制研究

Phenolic Extraction of Moringa Oleifera Leaves Induces Caspase-Dependent and Caspase-Independent Apoptosis through the Generation of Reactive Oxygen Species and the Activation of Intrinsic Mitochondrial Pathway in Human Melanoma Cells

Moringa oleifera Lam. has long been used to treat many diseases, including diabetes, aging, inflammatory, and cancer. Many studies have revealed that the crude extract of Moringa oleifera Lam. leaves possesses anticancer property. Therefore, in this study, the extract of Moringa oleifera leaves was fractionated using different solvents to figure out the most effective fraction for anti-proliferative effect on melanoma cells. Methanol extract (MO-ME), hexane fraction (MO-HE), chloroform fraction (MO-CH), ethyl acetate fraction (MO-EA), and water-soluble fraction (MO-WA) of Moringa oleifera leaves were prepared. Total phenolic and flavonoid contents were determined. The anti-proliferative activity on melanoma cells and normal cells was investigated using WST-1 assay. The apoptotic activity was assessed by testing DNA condensation, DNA fragmentation, and phosphatidylserine (PS) externalization. The expression of apoptosis-related genes, the mitochondrial depolarization, and reactive oxygen species (ROS) were then examined to clarify the underlying molecular mechanisms. In this regard, MO-ME, MO-EA, and MO-CH inhibited the proliferation of both A375 human melanoma cells and A2058 human melanoma cells, but had little effect on WS1 normal human skin fibroblasts and primary normal human dermal fibroblasts (NHDF). Among fractions, the phenolic-rich MO-EA markedly inhibited the growth of A375 cells in a dose- and time-dependent manner. The anti-proliferation was supposed to be mediated via apoptosis, which was demonstrated by the significant increase of condensed chromatin, DNA fragmentation, and PS externalization. The apoptosis was stimulated by enhanced ROS production and reduction of mitochondrial membrane potential. MO-EA activated Bax while reducing Bcl-2 expression, leading to an increase in Bax/Bcl-2 ratio. The mechanisms of cell death involved in activation of Caspase-3/7 and Caspase-9 (Caspase-dependent pathway), activation, and translocation of apoptosis-inducing factor (AIF) into the nucleus (Caspase-independent pathway). Our study indicated that the phenolic-rich fraction exerted significant anticancer effects on melanoma cells in vitro which involved in Caspase-dependent and Caspase-independent apoptosis pathways mediated by mitochondrial ROS. These results provided a fundament for the using of phenolic-rich fraction of Moringa oleifera leaves to treat skin cancer effectively.

Melatonin inhibits human melanoma cells proliferation and invasion via cell cycle arrest and cytoskeleton remodeling

Among skin cancers,
 melanoma has the highest mortality rate. The heterogeneous genetic melanoma
 background leads to a tumor-propagating capacity particularly important in
 maintaining therapeutic resistance, and tumor recurrence. The identification of
 efficient molecules able to control melanoma progress represents an important
 opportunity for new therapeutic strategies, particularly in combination with the
 current standard-of-care treatments. In this context,
 several studies have reported the antitumor effects of melatonin against
 different types of cancer, including melanoma. Here,
 we describe the underlying mechanisms associated with melatonin’s activity in
 human melanoma cell lines, focusing on cell cycle and cytoskeleton
 remodeling. Interestingly, while melatonin induced melanocyte
 DNA replication, melanoma cells exhibited cell cycle arrest in the G1-phase.
 This phenomenon was associated with cyclin-D1 downregulation or p21
 overexpression. The efficacy of melatonin on melanoma cells survival and
 proliferation was detected using the clonogenic assay, with a decrease in both
 the number and size of colonies. Additionally, melatonin induced a dramatic
 cytoskeleton remodeling in all melanoma cell lines, leading to a star-like
 morphology or cell swelling. The role of melatonin on melanoma cytoskeleton was
 associated with the actin disruption, with thinning and/or broken actin fibers,
 and weak and/or loss of paxillin along stress fibers. These data support the
 observed findings that melatonin impairs melanoma invasion in skin
 reconstructed models. Together, our results suggest that melatonin could be
 used to control melanoma growth and support basic and
 clinical studies on melatonin as a promising immunometabolic
 adjuvant for melanoma therapy.

22β-hydroxytingenone reduces proliferation and invasion of human melanoma cells

Melanoma is a skin cancer with high invasive potential and high lethality. Considering that quinonemethide triterpenes are described as promising anticancer agents, the aim of this study was to evaluate the effect of 22β-hydroxytingenone (22-HTG) against human melanoma cells. Alamar blue assay was performed in order to evaluate its cytotoxic effect. Thus, subtoxic concentrations (1.0, 2.0, and 2.5 μM) were used to evaluate the effect of this compound on proliferation, migration, metabolism, and invasion. IC50 value against SK-MEL-28 cell line was 4.35, 3.72, and 3.29 μM after 24, 48, and 72 h of incubation, respectively. 22-HTG reduced proliferation, migration and invasion by melanoma cells, with decreased activity of metalloproteinases (MMP-2 and MMP-9). Futhermore, 22-HTG decreased expression of lactate dehydrogenase (LDHA), an enzyme associated with cell metabolism. Howerver, the small reduction in LDHA enzyme activity must have occurred by the cytotoxic effect of 22-HTG. According to the results, 22-HTG interferes with important characteristics of cancer, with anti-proliferative, and anti-invasive effect against melanoma cells. The data suggest that 22-HTG is an effective substance against melanoma cells and it should be considered as a potential anticancer agent.

Cytotoxic and proapoptotic effect of doxycycline – An in vitro study on the human skin melanoma cells

Doxycycline is a semisynthetic, second generation tetracycline. Currently, it is used, among others, in the treatment of acne and skin infections. Moreover, doxycycline has many valuable nonantibiotic properties, including anti-inflammatory, immunosuppressive and anticancer effects. Recent studies showed that the drug had the ability to inhibit the adhesion and migration of cancer cells, as well as affected their growth and proliferation and induced apoptosis. The purpose of this study was to examine the antimelanoma effect of doxycycline. The obtained results demonstrated that doxycycline decreased the viability and inhibited the proliferation of human melanoma cells, proportionally to the drug concentration and the treatment time. It was stated that doxycycline disturbed the homeostasis of the cells by lowering intracellular level of reduced thiols. In addition, the treatment changed the cell cycle profile and triggered the DNA fragmentation. Mitochondria of melanoma cells exposed to the drug had lowered membrane potential, which indicated cells apoptosis. Finally, doxycycline induced the externalization phosphatidylserine – a well-known hallmark of apoptosis, confirmed by results of annexin V test. The presented study contributes to the increase of knowledge about nonantibacterial action of doxycycline, including the influence on human cancer cells and indicates new potential possibility of effective treatment of malignant melanoma.

A Potential Tumor Suppressor Gene Named miR-508-5p Inhibited the Proliferation and Invasion of Human Melanoma Cells by Targeting KIT

Melanoma is the main death cause of human skin cancer. Increasing evidences demonstrate that microRNAs act as key roles in mediating tumor occurrence and progression. MiR-508-5p has proved to participate in the development of various types of human malignancies. However, the role of miR-508-5p in melanoma remained unclear. In in vitro study, miR-508-5p level in peripheral blood samples of patients with melanoma and human melanoma A375 cells was downregulated compared to that in normal peripheral blood samples or normal human epidermal melanocytes (MHEM). MiR-508-5p overexpression significantly inhibited the cell proliferation, migration and invasion in A375 cells, and thus inhibiting KIT expression at both gene and protein levels. Furthermore, western blot analysis showed miR-508-5p reduced cell proliferation by targeting KIT to modulate RAS/RAF/MEK/ERK pathway. Taken together, we speculated that miR-508-5p functioned as an important suppressor in human melanoma by targeting KIT, suggesting miR-508-5p might be a promising tumor suppressor gene for further target therapies from bench to clinic.

CircMYC Regulates Glycolysis and Cell Proliferation in Melanoma.

Circular RNAs (cicRNAs) have been identified to play pivotal roles in several cancer types. However, functions of circRNA in malignant melanoma are poor defined. Our current study demonstrated that human circMYC was obviously upregulated in human melanoma tissue. Furthermore, circMYC promoted the proliferation of human melanoma cells and Mel-CV cells. The expression of circMYC can repress Mel-CV cell glycolysis and LDHA activities in the in vitro glycolysis and lactate production evaluations. circMYC directly bound to miR-1236 as a molecular sponge that targeting miR-1236 in Mel-CV cells via bioinformatics analysis, pull-down assay, and luciferase reporter assays. Our present study revealed that 3' UTR of LDHA acted as a target of miR-1236 using Mel-CV cells. Based on our findings, c-MYC-SRSF1 axis may regulate the production of circMYC. Overall, these results elucidate potential effects of circMYC in melanoma development and provide a promising biomarker for melanoma diagnosis.

Oxyresveratrol drives caspase-independent apoptosis-like cell death in MDA-MB-231 breast cancer cells through the induction of ROS

Earlier studies from our laboratory have demonstrated that Oxyresveratrol (OXY), a hydroxyl-substituted stilbene, exhibits potent inhibition of human melanoma cell proliferation. The present study defines a cytotoxic effect of OXY on the highly chemo-resistant, triple-negative human breast cancer cell line MDA-MB-231. OXY-mediated cell death resulted in accumulation of cells at the sub-G1 phase of the cell cycle, induced chromatin condensation, DNA fragmentation, phosphatidylserine externalization and PARP cleavage, indicative of apoptosis. Interestingly, morphology and cell viability studies with the pan-caspase inhibitor, QVD-OPH revealed that OXY-induced cell death was caspase-independent. Docking studies also showed that OXY can bind to the S1 site of caspase-3, and could also exert an inhibitory effect on this executioner caspase. The immunoblot analysis demonstrating the absence of caspase cleavage during cell death further confirmed these findings. OXY was also observed to induce the production of reactive oxygen species, which caused the depolarization of the mitochondrial membrane resulting in translocation of Apoptosis Inducing Factor (AIF) into the nucleus. Pretreatment of the cells with N-Acetyl Cysteine antioxidant prevented cell death resulting from OXY treatment. Thus, OXY initiates ROS-mediated, apoptosis-like cell death, involving mitochondrial membrane depolarization, translocation of AIF into the nucleus, and DNA fragmentation, resulting in caspase-independent cell death in MDA-MB-231 cells. The cytotoxicity manifested by OXY was also observed in 3D cell culture models and primary cells, thereby providing a basis for the utilization of OXY as a novel template for the future design of anticancer therapeutics.

Search for novel STAT3-dependent genes reveals SERPINA3 as a new STAT3 target that regulates invasion of human melanoma cells

Transcription factor signal transducer and activator of transcription 3 (STAT3) is constitutively activated in many cancers and promotes uncontrolled tumor growth and progression through multiple mechanisms. Compelling evidence shows tissue and cell-specific sets of STAT3 targets. Transcriptional targets of STAT3 in melanoma cells are largely unknown. Malignant melanoma is a deadly disease with highly aggressive and drug-resistant behavior. Less than 10% of patients with advanced melanomas reach the 5-year survival, partly due to the aggressive character of the tumor and ineffectiveness of current therapeutics for treating metastatic melanoma. STAT3 is constitutively activated in melanoma cells and plays important roles in its growth and angiogenesis in tumor xenograft studies. Moreover, highly metastatic melanoma cells have higher levels of active STAT3 than poorly metastatic ones. To identify genes that are driven by STAT3 in human melanoma cells, we performed JAK/STAT signaling specific and global gene expression profiling of human melanoma cells with silenced STAT3 expression. For selected genes, we performed computational identification of putative STAT3-binding sites and validated direct interactions STAT3 with defined promoters by using chromatin immunoprecipitation followed by qPCR. We found that STAT3 knockdown does not affect human melanoma cell viability, proliferation, or response to chemotherapeutics. We show that STAT3 regulates a discrete set of genes in melanoma cells, including SERPINA3, a novel STAT3 target gene, which is functionally involved in regulation of melanoma migration and invasion. Knockdown of STAT3 impaired cell migration and invasion, in part via regulation of its transcriptional target SERPINA3. Our results present novel targets and functions of STAT3 in melanoma cells.

Enhanced migration and proliferation of human melanoma cells by nonessential amino acid proline

Enhanced migration and proliferation of human melanoma cells by nonessential amino acid proline

Knockdown of SSATX, an alternative splicing variant of the SAT1 gene, promotes melanoma progression

Alternative splicing can generate multiple protein messages from a single gene and has emerged as an important mechanism to regulate cancer pathways. The human SAT1 gene produces two transcript variants: one translates spermidine/spermine N-1 acetyltransferase (SSAT1), the rate-limiting enzyme in the catabolism of polyamines, and the other generates SSATX, which has largely unknown biological functions. Here, we used experimental data and analyses of several melanoma transcriptome datasets to reveal that SSATX is weakly expressed in melanoma cells. SSATX knockdown promoted the proliferation, migration, and invasion of human melanoma cells via the activation of the Wnt signaling pathway in a manner that was independent of SSAT1 expression. Based on our data, we propose that SSATX functions as a long non-coding RNA prior to its degradation in melanoma cells. Overall, our findings indicate that SSATX acts as a tumor suppressor, which may aid the future diagnosis and treatment of melanoma.

MicroRNA-338-3p suppresses cell proliferation, migration and invasion in human malignant melanoma by targeting MACC1.

Malignant melanoma (MM) is the most aggressive form of skin cancer originating from melanocytes with increased proliferative and metastatic ability. Previous studies have revealed that microRNA-338-3p (miR-338-3p) functions as a tumor suppressor in several types of cancer, including cervical cancer, renal cell carcinoma and thyroid cancer. However, the function and mechanism underlying the action of miR-383-3p in MM remain unclear. In the study, aberrant downregulation of miR-338-3p was observed in 60 pairs of MM and adjacent non-tumor tissue using quantitative polymerase chain reaction assay. Decreased miR-383-3p expression was associated with advanced clinical stage (P<0.05) and lymph node metastasis (P<0.001). The overexpression of miR-338-3p in A375 and G361 cells suppressed cell proliferation and migration using MTT, colony formation, wound healing and transwell assays. Mechanistically, MACC1 was identified as a direct target for miR-338-3p using bioinformatics prediction and dual-luciferase assays. Furthermore, MACC1 expression was significantly increased and inversely correlated with the levels of miR-338-3p in MM tissues. More importantly, restoration of MACC1 resulted in reversed the inhibitory effects of miR-338-3p overexpression on MM cells by altering the expression levels of PCNA and epithelial-mesenchymal transition (EMT)-associated proteins. These results suggest that miR-338-3p functions as a novel tumor suppressor, at least in part, via targeting MACC1 and suggest that miR-338-3p may serve as a potential target for treatment of MM patients.

Propofol suppresses proliferation, invasion, and migration of human melanoma cells via regulating microRNA-137 and fibroblast growth factor 9.

Propofol is an intravenous anesthetic widely used in clinical surgeries, such as tumor resection. Propofol affects the growth of many cancers, though its effect on melanoma is unknown. Our study aimed to explore how propofol affects melanoma cells. Melanoma cells A2058 and WM793B were cultured with propofol for 24 hr. Propofol significantly suppressed proliferation, migration, and invasion of A2058 and WM793B cells. Lower miR-137 level was observed in A2058 and WM793B cells, compared with normal human epidermal melanocyte HEMa-LP cells. Propofol-induced miR-137 upregulation and decreased proliferation, invasive ability, and migrated ability of A2058 and WM793B cells. Transfection with the miR-137 inhibitor reversed these effects. Additionally, miR-137 was verified to target and negatively regulate fibroblast growth factor 9 (FGF9) expression. Propofol efficiently downregulated FGF9 protein expression by upregulating miR-137. Furthermore, FGF9 overexpression abrogated propofol's repressive effects on the malignant potential of A2058 and WM793B cells. These findings indicate that propofol suppressed melanoma cell proliferation, invasion, and migration by regulating miR-137 and FGF9.

Antifungal Agents Induce Apoptotic and Non‐Apoptotic Cell Death in Human Melanoma Cells

Patients with melanoma, the most aggressive form of skin cancer, have poor survival rates due to the resistance of advanced stage tumors to chemotherapy. This resistance appears to involve the dysregulation of apoptosis, such that inhibition of apoptotic progression allows melanoma cells to survive after treatment. We previously reported a potentially novel treatment for melanoma, where antifungal agents led to profound decreases in growth and proliferation of human melanoma cells. Our objective here was to analyze cell death pathways induced in human melanoma cell lines following treatment with antifungal agents. Cell death pathways were investigated via flow cytometry, cell proliferation assays, and immunoblotting after treatments.Several lines of human melanoma and normal skin cells were analyzed. Apoptosis, via flow cytometry and analysis of activated caspases and PARP1 cleavage, was observed in all melanoma lines after treatment with clotrimazole and econazole. Caspase‐independent cell death was also observed in most melanoma lines after similar treatments. No extensive cell death was induced by these treatments in noncancerous human skin cells. These results indicated that antifungal agents selectively induced cytotoxicity in human melanoma lines. Because varying levels of cell death were observed among different melanoma lines after antifungal treatment, further studies will be required to ascertain the reason for these differential responses to treatment. Taken together, these results indicated that clotrimazole and econazole initiated apoptotic and non‐apoptotic cell death in human melanoma cells.In conclusion, this study demonstrated the induction of apoptotic and non‐apoptotic cell death in human melanoma skin cell lines after treatment with antifungal agents. Differential levels of various cell death pathways were observed among all melanoma lines. This was corroborated by the various levels of efficacious treatment produced by these agents. Taken together, we conclude that clotrimazole and econazole induce cell death in human melanoma cells. These agents thus appear to have in vitro efficacy toward the treatment of human melanoma.Support or Funding InformationThis research was supported in part by the Bower, Bennet &amp; Bennet Endowed Chair Award from the Ohio Northern University College of Pharmacy and the Ohio Northern University Summer Research stipend.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The nonessential amino acid proline enhances migration and proliferation of human melanoma cells

The nonessential amino acid proline enhances migration and proliferation of human melanoma cells

Periostin Links Skin Inflammation to Melanoma Progression in Humans and Mice.

It is widely accepted that chronic inflammation initiates and promotes carcinogenesis and tumor progression in various cell types. However, this paradigm has not been comprehensively investigated in melanoma. To investigate the effects of chronic inflammation on the progression of melanoma, we established a murine inflammatory skin model and investigated the relationship between skin inflammation and melanoma progression. In a murine model, B16F10 melanoma cells in inflamed skin grew significantly more rapidly than cells in control skin. The stromal expression of periostin was upregulated in inflamed skin, and significantly more CD163+ M2 macrophages were recruited to the melanomas in inflamed skin. We then immunohistologically examined the expression of stromal periostin and the infiltration of CD163+ M2 macrophages in human acral lentiginous melanomas (n = 94) and analyzed the statistical associations with clinicopathological variables. In human melanomas, high periostin expression and a large number of infiltrated M2 macrophages were significantly correlated with poor prognosis. Furthermore, we confirmed that periostin promotes the proliferation of murine and human melanoma cells in vitro. Our findings indicate that periostin and M2 macrophages play a critical role in melanoma progression and prognosis in both humans and mice, indicating that periostin is a potential target for treating progressive melanoma.

Baicalein restrains proliferation, migration, and invasion of human malignant melanoma cells by down-regulating colon cancer associated transcript-1.

Baicalein (BAI) is an acknowledged flavonoids compound, which is regarded as a useful therapeutic pharmaceutical for numerous cancers. However, its involvement in melanoma is largely unknown. This study aimed to examine the anti-melanoma function of BAI and unraveled the regulatory mechanism involved. A375 and SK-MEL-28 were treated with BAI for 24 h. Then, CCK-8 assay, flow cytometry, and transwell assay were carried out to investigate cell growth, migration, and invasion. RT-qPCR was applied to detect the expression of colon cancer associated transcript-1 (CCAT1) in melanoma tissues and cells. The functions of CCAT1 in melanoma cells were also evaluated. Western blot was utilized to appraise Wnt/β-catenin or MEK/ERK pathways. BAI restrained cell proliferation and stimulated cell apoptotic capability of melanoma by suppressing cleaved-caspase-3 and cleaved-PARP. Cell migratory and invasive abilities were restrained by BAI via inhibiting MMP-2 and vimentin. CCAT1 was over-expressed in melanoma tissues and down-regulated by BAI in melanoma cells. Overexpressed CCAT1 reversed the BAI-induced anti-growth, anti-migratory, and anti-invasive effects. Furthermore, BAI inhibited Wnt/β-catenin and MEK/ERK pathways-axis via regulating CCAT1. Our study indicated that BAI blocked Wnt/β-catenin and MEK/ERK pathways via regulating CCAT1, thereby inhibiting melanoma cell proliferation, migration, and invasion.

Cell surface CD63 increased by up-regulated polylactosamine modification sensitizes human melanoma cells to the BRAF inhibitor PLX4032.

The BRAF inhibitor PLX4032 is effective in treating BRAF-mutated melanoma; however, because drug resistance develops in most cases, it is critical to develop a new strategy for inhibiting drug-resistant melanoma growth. The melanoma-associated membrane glycoprotein CD63 is involved in cell proliferation and metastasis. Here, we found that cell surface CD63 suppresses the proliferation of human melanoma cells and PLX4032-resistant cells. Endogenous CD63 protein levels were negatively correlated with PLX4032 resistance of human melanoma cell lines. CD63 overexpression in these cells, in which endogenous CD63 levels are low, suppressed cell proliferation under PLX4032 treatment. The cell surface levels and average molecular mass of CD63 were increased with PLX4032 treatment because of the up-regulated polylactosamine modification caused by induced β1,3- N-acetylglucosaminyltransferase 2 expression, which is involved in polylactosamine synthesis. Forced cell surface localization of CD63 led to reduced melanoma cell proliferation without PLX4032 treatment. CD63 overexpression in PLX4032-resistant cells, in which CD63 levels were lower and cell surface polylactosamine levels were higher than those in parental cells, effectively suppressed proliferation. Our study shows the potential of CD63 to sensitize melanoma cells to PLX4032 and to reduce the proliferation of PLX4032-resistant cells.-Kudo, K., Yoneda, A., Sakiyama, D., Kojima, K., Miyaji, T., Yamazaki, M., Yaita, S., Hyodo, T., Satow, R., Fukami, K. Cell surface CD63 increased by up-regulated polylactosamine modification sensitizes human melanoma cells to the BRAF inhibitor PLX4032.