Melanoma Cells Research Articles

Tubulin-Targeted Therapy in Melanoma Increases the Cell Migration Potential by Activation of the Actomyosin Cytoskeleton─An In Vitro Study.

One of the most dangerous aspects of cancers is their ability to metastasize, which is the leading cause of death. Hence, it holds significance to develop therapies targeting the eradication of cancer cells in parallel, inhibiting metastases in cells surviving the applied therapy. Here, we focused on two melanoma cell lines─WM35 and WM266-4─representing the less and more invasive melanomas. We investigated the mechanisms of cellular processes regulating the activation of actomyosin as an effect of colchicine treatment. Additionally, we investigated the biophysical aspects of supplement therapy using Rho-associated protein kinase (ROCK) inhibitor (Y-27632) and myosin II inhibitor ((-)-blebbistatin), focusing on the microtubules and actin filaments. We analyzed their effect on the proliferation, migration, and invasiveness of melanoma cells, supported by studies on cytoskeletal architecture using confocal fluorescence microscopy and nanomechanics using atomic force microscopy (AFM) and microconstriction channels. Our results showed that colchicine inhibits the migration of most melanoma cells, while for a small cell population, it paradoxically increases their migration and invasiveness. These changes are also accompanied by the formation of stress fibers, compensating for the loss of microtubules. Simultaneous administration of selected agents led to the inhibition of this compensatory effect. Collectively, our results highlighted that colchicine led to actomyosin activation and increased the level of cancer cell invasiveness. We emphasized that a cellular pathway of Rho-ROCK-dependent actomyosin contraction is responsible for the increased invasive potential of melanoma cells in tubulin-targeted therapy.

EIF4F controls ERK MAPK signaling in melanomas with BRAF and NRAS mutations

The eIF4F translation initiation complex plays a critical role in melanoma resistance to clinical BRAF and MEK inhibitors. In this study, we uncover a function of eIF4F in the negative regulation of the rat sarcoma (RAS)/rapidly accelerated fibrosarcoma (RAF)/mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) signaling pathway. We demonstrate that eIF4F is essential for controlling ERK signaling intensity in treatment-naïve melanoma cells harboring BRAF or NRAS mutations. Specifically, the dual-specificity phosphatase DUSP6/MKP3, which acts as a negative feedback regulator of ERK activity, requires continuous production in an eIF4F-dependent manner to limit excessive ERK signaling driven by oncogenic RAF/RAS mutations. Treatment with small-molecule eIF4F inhibitors disrupts the negative feedback control of MAPK signaling, leading to ERK hyperactivation and EGR1 overexpression in melanoma cells in vitro and in vivo. Furthermore, our quantitative analyses reveal a high spare signaling capacity in the ERK pathway, suggesting that eIF4F-dependent feedback keeps the majority of ERK molecules inactive under normal conditions. Overall, our findings highlight the crucial role of eIF4F in regulating ERK signaling flux and suggest that pharmacological eIF4F inhibitors can disrupt the negative feedback control of MAPK activity in melanomas with BRAF and NRAS activating mutations.

DNA-PK inhibition enhances neoantigen diversity and increases T cell responses to immunoresistant tumors.

Effective antitumor T cell activity relies on the expression and MHC presentation of tumor neoantigens. Tumor cells can evade T cell detection by silencing the transcription of antigens or by altering MHC machinery resulting in inadequate neoantigen-specific T cell activation. We identified DNA-PK inhibitor (DNA-PKi) NU7441 as a promising immunomodulator that reduced immunosuppressive proteins while increasing MHC-I expression in a panel of human melanoma cell lines. In tumor-bearing mice, combination therapy using NU7441 and immune adjuvants STING ligand and CD40 agonist (NU-SL40) substantially increased and diversified the neoantigen landscape, antigen presenting machinery, and consequently substantially increased both the number and repertoire of neoantigen-reactive tumor infiltrating lymphocytes (TILs). DNA-PK-inhibition or knockout promoted transcription and protein expression of various neoantigens in human and mouse melanomas and induced sensitivity to ICB in resistant tumors. In patients, PRKDC levels inversely correlated with MHC I expression and CD8 TILs but positively correlated with increased neoantigen loads and improved responses to ICB. These studies suggest that inhibiting DNA-PK activity can restore tumor immunogenicity by increasing neoantigen expression and presentation and broadening the neoantigen-reactive T cell population.

Soluble CD146 cooperates with VEGF-A to generate an immunosuppressive microenvironment in CD146-positive tumors: interest of a combined antibody-based therapy.

Tumor development necessitates immune escape through different mechanisms. To counteract these effects, the development of therapies targeting Immune Checkpoints (ICP) has generated interest as they have produced lasting objective responses in patients with advanced metastatic tumors. However, many tumors do not respond to inhibitors of ICP, necessitating to further study the underlying mechanisms of exhaustion. Vascular Endothelial Growth Factor a (VEGFa), a pro-angiogenic molecule secreted by tumors, was described to participate to tumor immune exhaustion by increasing ICP, justifying in part the use of an anti-VEGFa monoclonal antibody (mAb), bevacizumab, in patients. However, recent studies from our group have demonstrated that tumors can escape anti-VEGFa therapy through the secretion of soluble CD146 (sCD146). In this study, we show that both VEGFa and sCD146 cooperate to create an immunosuppressive microenvironment by increasing the expression of ICP. In addition, sCD146 favors pro-tumoral M2-type macrophages and induces the secretion of pro-inflammatory cytokines. An anti-sCD146 mAb reverses these effects and displays additive effects with anti-VEGFa antibody to eliminate tumors in a syngeneic murine model grafted with melanoma cells. Combining bevacizumab with mucizumab could thus be of major therapeutic interest to prevent immune escape in malignant melanoma and other CD146-positive tumors.

A co-culture model to study modulators of tumor immune evasion through scalable arrayed CRISPR-interference screens.

Cancer cells effectively evade immune surveillance, not only through the well-known PD-1/PD-L1 pathway but also via alternative mechanisms that impair patient response to immune checkpoint inhibitors. We present a novel co-culture model that pairs a reporter T-cell line with different melanoma cell lines that have varying immune evasion characteristics. We developed a scalable high-throughput lentiviral arrayed CRISPR interference (CRISPRi) screening protocol to conduct gene perturbations in both T-cells and melanoma cells, enabling the identification of genes that modulate tumor immune evasion. Our study functionally validates the co-culture model system and demonstrates the performance of the CRISPRi-screening protocol by modulating the expression of known regulators of tumor immunity. Together, our work provides a robust framework for future research aimed at systematically exploring mechanisms of tumor immune evasion.

DNA-Binding Protein A Is Actively Secreted in a Calcium-and Inflammasome-Dependent Manner and Negatively Influences Tubular Cell Survival.

DNA-binding protein A (DbpA) belongs to the Y-box family of cold shock domain (CSD) proteins that bind RNA/DNA and exert intracellular functions in cell stress, proliferation, and differentiation. Given the pattern of DbpA staining in inflammatory glomerular diseases, without adherence to cell boundaries, we hypothesized extracellular protein occurrence and specific functions. Lipopolysaccharide and ionomycin induce DbpA expression and secretion from melanoma and mesangial cells. Unlike its homologue Y-box-binding protein 1 (YB-1), DbpA secretion requires inflammasome activation, as secretion is blocked upon the addition of a NOD-like receptor protein-3 (NLRP3) inhibitor. The addition of recombinant DbpA enhances melanoma cell proliferation, migration, and competes with tumor necrosis factor (TNF) binding to its receptor (TNFR1). In TNF-induced cell death assays, rDbpA initially blocks TNF-induced apoptosis, whereas at later time points (>24 h), cells are more prone to die. Given that CSD proteins YB-1 and DbpA fulfill the criteria of alarmins, we propose that their release signals an inherent danger to the host. Some data hint at an extracellular complex formation at a ratio of 10:1 (DbpA:YB-1) of both proteins.

Multifunctional nanomaterials composed entirely of active pharmaceutical ingredients for synergistically enhanced antitumor and antibacterial effects.

Multifunctional nanomaterials are emerging as promising tools for treating both cancer and bacterial infections. However, integrating dual therapeutic capabilities into a single system remains challenging. This study presents multifunctional nanoparticles (ECI-NPs) based on Epigallocatechin gallate (EGCG) oligomers, Curcumin (CUR), and Indocyanine Green (ICG) for combined cancer and bacterial treatment. ECI-NPs were synthesized via oxidative coupling of EGCG, CUR, and ICG. The nanoparticles were characterized for stability, size, drug loading, and release profiles. Cellular uptake, phototoxicity in melanoma cells, and antibacterial activity against Escherichia coli and Staphylococcus aureus were also evaluated. ECI-NPs demonstrated optimal stability, high drug loading, and controlled release. Cellular studies showed increased uptake and greater phototoxicity in melanoma cells compared to free drugs. ECI-NPs also exhibited enhanced anticancer effects and strong antibacterial activity, outperforming the individual components. The polyphenol-based ECI-NPs offer synergistic therapeutic effects, overcoming the limitations of free drugs in terms of solubility and efficacy. This dual-function platform shows potential for broader biomedical applications, addressing challenges in cancer and bacterial infections. Further research will focus on in vivo studies and clinical translation.

Azacytidine treatment affects the methylation pattern of genomic and cell-free DNA in uveal melanoma cell lines

BackgroundUveal melanoma (UM) is the most common primary intraocular tumour in adults, and approximately 50% of patients will develop metastasis. Epigenetic changes are a major factor in cancer progression. We aimed to determine whether methylation profiles could be altered using a DNA methyltransferase (DNMT) inhibitor in UM cell lines.MethodsFour primary and metastatic UM cell lines were treated with azacytidine and analysed for cell proliferation, colony formation, and BAP1 protein expression. Genomic and cell-free (cf)DNA methylation were compared.ResultsIn all cell lines, azacytidine treatment resulted in dose-dependent effects on proliferation, colony formation, and radiosensitivity. Methylation profiling revealed differences in methylation between cell lines according to BAP1 expression. Matched primary and metastatic cell lines showed very similar patterns. Alterations were seen in pathways known to be important in UM progression, such as PI3K/Akt and MAPK signaling, and in pathways involved in cancer progression, such as regulation of stemlike potential, cell motility, and invasion. These changes were maintained in genomic and cell-free DNA.ConclusionsThis data suggests that DNMT inhibitors cause changes in UM cells that are maintained in cfDNA. The results suggest that targeting methylation in UM treatment and monitoring response to treatment using cfDNA methylation could be a valuable tool.

Different Doxorubicin Sensitivity Across Various Human Cancer Cell Lines

Doxorubicin (Dox) is a highly potent chemotherapeutic agent, approved by FDA since 1974, for treating a broad spectrum of cancers. However, development of severe side effects and drug resistance are main issues that limit the clinical use of Dox. Herein, we aimed to investigate the sensitivity of Dox in a variety of human cancer cell lines. Eleven cell lines were tested in this study including 2 hepatocellular carcinoma (HCC) cell lines (HepG2 and Huh7), 4 bladder cancer (BlCa) cell lines (UMUC-3, VMCUB-1, TCCSUP and BFTC-905), a lung cancer cell line (A549), a cervical carcinoma cell line (HeLa), a breast cancer cell line (MCF-7), a skin melanoma cell line (M21) and a noncancer human kidney cell line (HK-2). The MTT assay was employed for the determination of cytotoxicity. Cells were treated with various concentrations of Dox for 24 h. The half-maximal inhibitory concentration (IC50) of Dox was calculated to compare the Dox sensitivity among tested cell lines. The result showed that IC50 of Dox in HepG2, Huh7, UMUC-3, VMCUB-1, TCCSUP, BFTC-905, A549, HeLa, MCF-7, M21 and HK-2 cells were 12.2, > 20, 5.1, > 20, 12.6, 2.3, > 20, 2.9, 2.5, 2.8 and > 20 mM, respectively. BFTC-905 had the lowest IC50 value, therefore, it was the most sensitive to Dox. In contrast, Huh7, VMCUB-1 and A549 cells were resistant to Dox with IC50 values > 20 mM. Conclusions, we demonstrated that different human malignant cell lines had different sensitivity to Dox. BFTC-905 BlCa cell line had the highest sensitivity to Dox. Huh7, VMCUB-1 and A549 cell lines were resistant to Dox. Perhaps, the different Dox sensitivity in different cell lines was due to the different acquisition of Dox resistance mechanisms. Huh7, VMCUB-1 and A549 cell lines could be suitable cell models to investigate the molecular mechanism of Dox resistance in different cancers. HIGHLIGHTS Different types of cancer cell lines exhibited different sensitivity to doxorubicin. BFTC-905, MCF-7 and M21 cell lines were sensitive to doxorubicin. HepG2, UMUC-3, TCCSUP and HeLa cells were moderately sensitive to doxorubicin. Huh7, VMCUB-1, A549 and HK-2 cells were resistant to doxorubicin. Huh7, VMCUB-1 and A549 cell lines could be suitable cell models for investigating the molecular pathways of Dox resistance in different types of cancers. GRAPHICAL ABSTRACT

Comparison of the efficacy of alginate nanoparticles containing Cymbopogon citratus essential oil and citral on melanoma and breast cancer cell lines under normoxic and hypoxic conditions

BackgroundSolid tumors often develop hypoxic regions, leading to aggressive behavior and increased drug resistance.MethodsThe chemical composition of Cymbopogon citratus essential oil (EO) was analyzed using GC-MS. Alginate nanoparticles containing the EO and its primary component, citral, were synthesized via the ionic gelation method. Encapsulation was confirmed using ATR-FTIR analysis. The anticancer efficacy of C. citratus EO, citral, and their respective alginate nanoparticles was evaluated under normoxic (21% oxygen) and hypoxic (1% oxygen) conditions on breast cancer (MDA-MB-231) and melanoma (A-375) cell lines. Additionally, qPCR and flow cytometry were used to assess apoptosis gene expression ratios (Bax/Bcl-2) and levels of apoptosis.ResultsCitral (80.98%) was identified as the major component of the EO. Alginate nanoparticles containing C. citratus EO and citral (C. citratus-AlgNPs and citral-AlgNPs) were synthesized with particle sizes of 195 ± 4 nm and 222 ± 9 nm, and zeta potentials of -22 ± 3 mV and − 17 ± 1 mV, respectively. Both samples demonstrated significantly greater efficacy under hypoxic conditions. Citral and C. citratus-AlgNPs had IC50 values of 27 (19–39) µg/mL and 25 (4-147) µg/mL, respectively, against MDA-MB-231 and A-375 cells. Flow cytometry showed increased apoptosis under hypoxic conditions, with the highest rates observed for citral-AlgNPs and C. citratus-AlgNPs (84 ± 5 and 92 ± 5% in MDA-MB-231 and A-375 cells, respectively).ConclusionThis study demonstrates that alginate nanoparticles enhance the anticancer activity of C. citratus-AlgNPs and citral, particularly under hypoxic conditions, highlighting their potential for hypoxia-targeted cancer therapies.

Metastatic tumours to the parotid: A 20-year single institutional experience with an emphasis on 14 unusual presentations

The parotid gland is a rare site for distant metastasis. We aim to provide an overview of metastatic tumours to the parotid over the past 20 years, focusing on clinicopathological analysis of 14 rare diagnoses. To the best of our knowledge, we are the first group to present the most up-to-date and largest case series on unusual metastases to the parotid. A total of 93 metastatic cases were identified from 2004 to 2023, on the pathology information system at North West London Pathology, with squamous cell carcinoma (n = 45, 48.4 %) as the most common primary, followed by malignant melanoma (n = 29, 31.2 %) and Merkel cell carcinoma (n = 4, 4.3 %). We came across 14 rare tumours that had metastasised to the parotid, including metastatic adenocarcinoma from kidney (n = 3, 3.2 %), lung (n = 3, 3.2 %) and breast (n = 1, 1.1 %), olfactory neuroblastoma (n = 3, 3.2 %), soft tissue sarcoma (n = 2, 2.2 %), small cell carcinoma (n = 1, 1,1 %) and hidradenocarcinoma (n = 1, 1.1 %). Half of all secondary neoplastic lesions (50.5 %) were found in intra-parotid nodes, while the other half (49.5 %) were found in parotid parenchyma. Our study offers valuable insights into the various tumour types that can metastasise to the parotid across a wide age range. It underscores the necessity of maintaining a broad differential diagnosis. Keeping an open mind regarding the potential primary sources of the tumour is imperative for accurate diagnosis and effective treatment planning.

RSK2-mediated cGAS phosphorylation induces cGAS chromatin-incorporation-mediated cell transformation and cancer cell colony growth

Cyclic guanosine-adenosine monophosphate synthase (cGAS) is a key cytosolic DNA sensor that plays a pivotal role in the innate immune response. Although a decade of research on the cGAS has advanced our understanding of inflammasome formation, cytokine production, and signaling pathways, the role of cGAS in the nucleus remains unclear. In this study, we found that the nuclear localization of endogenous and stably expressed cGAS differed from transiently expressed cGAS, which mainly localized in the cytosol. In the nucleus, cGAS is tightly bound to chromatin DNA. The chromatin DNA binding of cGAS was dependent on RSK2. Our molecular mechanism study indicated that the N-lobe of RSK2 harboring 1–323 interacted with the NTase domain of cGAS harboring residues 213–330. This interaction increased RSK2-induced cGAS phosphorylation at Ser120 and Thr130, resulting in the tightly binding of cGAS to chromatin. Importantly, epidermal growth factor (EGF)-induced cell transformation and anchorage-independent colony growth showed an increase in growth factors, such as EGF or bFGF, in cGAS stable expression compared to mock expression. Notably, the cGAS-S120A/T130A mutant abolished the increasing effect of cell transformation of JB6 Cl41 cells and colony growth of SK-MEL-2 malignant melanoma cells. The results suggested that cGAS’s chromatin DNA binding, which is indispensable to RSK2-dependent phosphorylation of cGAS at Ser120/Thr130, provides the first clue to how cGAS may participate in chromatin remodeling in the nucleus.

Impact of senescence cell signature in patients with non-small cell carcinoma and melanoma receiving PD-L1/PD-1 inhibitors

Tumor cell senescence plays a crucial role in tumor immunity. We investigated whether the senescent cell signature (SCS) could predict prognosis in non-small cell carcinoma (NSCLC) and melanoma datasets treated with PD-L1/PD-1 inhibitors. Patients with high SCS expression exhibited elevated levels of interferon-gamma and T cell-inflamed signatures in three lung adenocarcinomas (LUAD), two squamous cell carcinoma (LUSC) and three melanoma datasets. The high SCS group was associated with PD-L1-related pathways such as IL6/JAK/STAT3 and TNF-alpha signaling via NF-kB in LUAD, LUSC, and melanoma datasets. A positive correlation was observed between several immune checkpoint markers and the SCS, indicating an immunosuppressive state in LUAD, LUSC and melanoma datasets. In patients treated with PD-1/PD-L1 inhibitors, a higher SCS was associated with a better prognosis, and a positive correlation between SCS and PD-L1 was observed in six independent NSCLC and three independent melanoma datasets. We used the LASSO Cox regression model to build a risk model focusing on the SCS genes that particularly predict prognosis. We confirmed that the model accurately predicts prognosis. However, the senescent immunohistochemical markers p16 and p21 could predict the response to PD-1/PD-L1 inhibitors in patients with LUSC and melanoma but not in patients with LUAD. SCS could serve as a valuable biomarker to complement PD-L1 expression in patients receiving PD-L1/PD-1 inhibitors.

Mannose-6-Phosphate Isomerase Functional Status Shapes a Rearrangement in the Proteome and Degradome of Mannose-Treated Melanoma Cells.

Metabolic reprogramming is a ubiquitous feature of transformed cells, comprising one of the hallmarks of cancer and enabling neoplastic cells to adapt to new environments. Accumulated evidence reports on the failure of some neoplastic cells to convert mannose-6-phosphate into fructose-6-phosphate, thereby impairing tumor growth in cells displaying low levels of mannose-6-phosphate isomerase (MPI). Thus, we performed functional analyses and profiled the proteome landscape and the repertoire of substrates of proteases (degradome) of melanoma cell lines with distinct mutational backgrounds submitted to treatment with mannose. Our results suggest a significant rearrangement in the proteome and degradome of melanoma cell lines upon mannose treatment including the activation of catabolic pathways (such as protein turnover) and differences in protein N-terminal acetylation. Even though MPI protein abundance and gene expression status are not prognostic markers, perturbation in the network caused by an exogenous monosaccharide source (i.e., mannose) significantly affected the downstream interconnected biological circuitry. Therefore, as reported in this study, the proteomic/degradomic mapping of mannose downstream effects due to the metabolic rewiring caused by the functional status of the MPI enzyme could lead to the identification of specific molecular players from affected signaling circuits in melanoma.

In vitro effects of l-kynurenine and quinolinic acid on adhesion, migration and apoptosis in B16 F10 melanoma cells

IntroductionThe inhibition of melanoma adhesion through adhesion molecules, such as integrins and E-cadherin, may represent a promising strategy for managing melanoma metastasis. Compounds, namely l-kynurenine (L-kyn) and quinolinic acid (Quin), previously displayed anti-cancer effects at half-maximal inhibitory concentration (IC50) against B16 F10 melanoma cells in vitro. However, the role of these compounds in B16 F10 melanoma cell adhesion, migration and apoptosis remain unknown. MethodsPost-exposure to the compounds, flow cytometry was used to analyse the expression of very late antigen-5 (VLA-5), E-cadherin and cleaved caspase-3 in B16 F10 melanoma and RAW 264.7 murine macrophage cells. An adhesion assay was used to quantify the adhesion of both cell lines to vitronectin. A scratch migration assay was used to measure the possible inhibition of cell migration in B16 F10 cells in response to L-kyn and Quin. ResultsIn both B16 F10 and RAW 264.7 cells, neither L-kyn nor Quin induced significant effects on VLA-5 expression or cell adhesion to vitronectin. In B16 F10 cells, both L-kyn and Quin elevated E-cadherin expression and displayed a trend of suppressed migration. However, only L-kyn elevated E-cadherin in RAW 264.7 cells. L-kyn induced apoptosis by elevating cleaved caspase-3 expression in both cell lines. ConclusionL-kyn and Quin demonstrated promising antimetastatic effects in their ability to elevate E-cadherin expression and induce apoptosis in B16 F10 melanoma cells. However, these effects did not occur in response to vitronectin or VLA-5 integrin alterations. Furthermore, it cannot be excluded that L-kyn also induced apoptosis in RAW 264.7 cells. As such, these effects should be confirmed in additional control cell lines and substantiated with in vivo models.

Secreted Apoe rewires melanoma cell state vulnerability to ferroptosis.

A major therapeutic barrier in melanoma is the coexistence of diverse cellular states marked by distinct metabolic traits. Transitioning from a proliferative to an invasive melanoma phenotype is coupled with increased ferroptosis vulnerability. However, the regulatory circuits controlling ferroptosis susceptibility across melanoma cell states are unknown. In this work, we identified Apolipoprotein E (APOE) as the top lipid-metabolism gene segregating the melanoma MITFhigh/AXLlow proliferative/ferroptosis-resistant from MITFlow/AXLhigh invasive/ferroptosis-sensitive state. Mechanistically, ApoE secreted by the MITFhigh/AXLlow cells protects the invasive phenotype from ferroptosis-inducing agents by reducing the content of peroxidation-prone polyunsaturated fatty acids and boosting GPX4 levels both in vitro and in vivo. Whole-exome sequencing indicates that APOEhigh expression in patients with melanoma is associated with resistance to ferroptosis, regardless of APOE germline status. In aggregate, we found a ferroptosis-resistance mechanism between melanoma cell states relying on secreted ApoE and APOEhigh expression as a potential biomarker for poor ferroptosis response in melanoma.

Tumor Heterogeneity Shapes Survival Dynamics in Drug-Treated Cells, Revealing Size-Drifting Subpopulations.

The goal of this project was to demonstrate that subpopulations of cells in tumors can uniquely fluctuate in size in response to environmental conditions created during drug treatment, thereby acting as a dynamic "rheostat" to create a favorable tumor environment for growth. The cancer modeling used for these studies was subpopulations of melanoma cells existing in cultured and tumor systems that differed in aldehyde dehydrogenase (ALDH) activity. However, similar observations were found in other cancer types in addition to melanoma, making them applicable broadly across cancer. The approach was designed to show that either ALDHhigh and ALDHlow subpopulations rapidly epigenetically transition between stem-cell-like high into nonstem-like low production states to create an environment during drug treatment that would enable optimal cellular proliferation and tumor expansion to facilitate drug resistance. The controlled experiments showed proportional changes in each cell population to reach an evolutionarily stable equilibrium mediated by the needed levels of ALDH enzyme activity. Mechanistically, cell population size changes served to functionally move the aldehyde and the resulting reactive oxygen species (ROS) levels to those compatible with optimal cellular proliferation with population fluctuations dependent on the levels of drug induced tumor stress. This is the first report documenting fluctuations in the sizes of cell populations in tumors to cooperatively assist in drug resistance development.

Parthenolide Inhibits Tumor Cell Growth and Metastasis in Melanoma A2058 Cells.

Skin melanoma is a potentially lethal cancer and ranks as the 17th most common cancer worldwide. Overcoming resistance to advanced-stage melanoma is a significant challenge in its treatment. Parthenolide (PAR) is recognized as a potent anticancer small molecule, yet its potential in treating melanoma is poorly investigated. Our objective was to investigate the apoptotic and anti-metastatic properties of PAR against the A2058 melanoma cells in vitro. This study employed various assays, such as cytotoxicity, apoptosis, cell cycle analysis, reactive oxygen species (ROS) production, mRNA expressions, western blotting, gelatin zymography, and scratch assay. The synergy between PAR and dacarbazine, a chemotherapy drug for treating skin cancer, was also assessed. Our study revealed that PAR significantly reduced the viability of A2058 cancer cells, demonstrating greater potency against cancer cells compared to normal L929 cells (IC50: 20 μM vs. 27 μM after 24h). PAR increased ROS production, elevated mRNA expression of pro-apoptotic Bax and NME1 genes, and decreased expression of the MITF gene. PAR induced apoptosis and cell cycle arrest in A2058 cells, as evidenced by the increased proportion of cells in the late apoptotic phase and sub-G1 cell cycle arrest. MMP-2 and MMP-9 mRNA and protein expressions, gelatinase activity, and the migration of A2058 cells were also decreased by PAR, suggesting its potential to suppress cancer cell invasion. These results, along with the synergic effect with dacarbazine, indicated that PAR may have the potential to be a therapeutic drug for melanoma by triggering apoptosis and suppressing invasion and migration.

Doramectin Induces Apoptosis in B16 Melanoma Cells.

Metastatic melanoma resists current pharmacological regimens that act through apoptosis. This indicates that therapies acting via non-apoptotic cell-death pathways could be pursued. Doramectin has shown promising results in another cancer of neural crest origin, neuroblastoma, through the inhibition of growth via autophagy. Our research hypothesis is that doramectin induces autophagy in B16F10 melanoma cells. Cells were treated with doramectin (15 uM) or a combination of both doramectin and a cell-death inhibitor, compared to untreated control cells (media), and then analyzed with MTT analysis. Likewise, MDC analysis was completed to detect autophagy involvement with doramectin treatment. Flow cytometry and TUNEL Assay were conducted to observe cell death-related effects. MTT analysis of doramectin-treated cells displayed a decrease in cell growth compared to control. Apoptotic morphology was prominent in melanoma cells treated with doramectin. Increased autophagy was not detected by fluorometric microscopic analysis. Flow cytometry analysis of doramectin-treated cells showed apoptosis as a major mode of cell death with some necrosis. Doramectin induces a novel cell-death mechanism in melanoma compared to other forms of cancer and should be studied as an effective anti-cancer agent for melanoma treatment.

Local Delivery of Ginger Extract via a Nanofibrous Membrane Suppresses Human Skin Melanoma B16F10 Cells Growth via Targeting Ras/ERK and PI3K/AKT Signaling Pathways: An In vitro Study.

Metastatic melanoma poses a significant threat globally, with a distressingly low ten-year survival rate of only 10%. While FDA-approved treatments such as dacarbazine and high-dose IL-2 have been employed in clinical settings, their limitations underscore the urgent need for more effective therapies. This study aimed to develop a potential anticancer local treatment through the extraction of various amounts of ginger extract loaded unto Poly(vinyl alcohol) (PVA) nanofibers. The anticancer activity of the produced membranes was studied on human skin melanoma B16F10 cells. Other in vitro experiments such as cell migration assay, cell proliferation assay, cell viability assay, scanning electron microscopy assay, real-time PCR assay, and ant-inflammatory assay were performed for the in vitro characterization of the delivery system. Tissue toxicity of the developed patches was studied in a rat model. The study showed that scaffolds loaded with 2%, 4%, 6%, 8%, and 0% of ginger extract had around 784.98 ± 202.31 nm, 771.86 ± 219.07 nm, 820.65 ± 242.43 nm, 785.19 ± 203.99 nm, and 671.29 ± 184.09 nm of mean fiber size, respectively. The ginger extract-loaded membranes suppressed the growth and migration activity of human skin melanoma B16F10 cells in a dose and time-dependent manner. Real-time PCR assay showed that the developed membranes modulated the expression levels of Ras/ERK and PI3K/AKT signaling pathways. Animal study results showed that our developed patches were not toxic against liver or skin tissues. Ginger extract-loaded PVA nanofibers exhibited promising anticancer potential against melanoma cells, suggesting a viable localized treatment option.