Melanoma Tumor Research Articles

Deleting the mitochondrial respiration negative regulator MCJ enhances the efficacy of CD8+ T cell adoptive therapies in pre-clinical studies

Mitochondrial respiration is essential for the survival and function of T cells used in adoptive cellular therapies. However, strategies that specifically enhance mitochondrial respiration to promote T cell function remain limited. Here, we investigate methylation-controlled J protein (MCJ), an endogenous negative regulator of mitochondrial complex I expressed in CD8 cells, as a target for improving the efficacy of adoptive T cell therapies. We demonstrate that MCJ inhibits mitochondrial respiration in murine CD8+ CAR-T cells and that deletion of MCJ increases their in vitro and in vivo efficacy against murine B cell leukaemia. Similarly, MCJ deletion in ovalbumin (OVA)-specific CD8+ T cells also increases their efficacy against established OVA-expressing melanoma tumors in vivo. Furthermore, we show for the first time that MCJ is expressed in human CD8 cells and that the level of MCJ expression correlates with the functional activity of CD8+ CAR-T cells. Silencing MCJ expression in human CD8 CAR-T cells increases their mitochondrial metabolism and enhances their anti-tumor activity. Thus, targeting MCJ may represent a potential therapeutic strategy to increase mitochondrial metabolism and improve the efficacy of adoptive T cell therapies.

Immune Regulation and Immune Therapy in Melanoma: Review with Emphasis on CD155 Signalling.

Melanoma is commonly diagnosed in a younger population than most other solid malignancies and, in Australia and most of the world, is the leading cause of skin-cancer-related death. Melanoma is a cancer type with high immunogenicity; thus, immunotherapies are used as first-line treatment for advanced melanoma patients. Although immunotherapies are working well, not all the patients are benefitting from them. A lack of a comprehensive understanding of immune regulation in the melanoma tumour microenvironment is a major challenge of patient stratification. Overexpression of CD155 has been reported as a key factor in melanoma immune regulation for the development of therapy resistance. A more thorough understanding of the actions of current immunotherapy strategies, their effects on immune cell subsets, and the roles that CD155 plays are essential for a rational design of novel targets of anti-cancer immunotherapies. In this review, we comprehensively discuss current anti-melanoma immunotherapy strategies and the immune response contribution of different cell lineages, including tumour endothelial cells, myeloid-derived suppressor cells, cytotoxic T cells, cancer-associated fibroblast, and nature killer cells. Finally, we explore the impact of CD155 and its receptors DNAM-1, TIGIT, and CD96 on immune cells, especially in the context of the melanoma tumour microenvironment and anti-cancer immunotherapies.

Quantifying in vivo collagen reorganization during immunotherapy in murine melanoma with second harmonic generation imaging.

Increased collagen linearization and deposition during tumorigenesis can impede immune cell infiltration and lead to tumor metastasis. Although melanoma is well studied in immunotherapy research, studies that quantify collagen changes during melanoma progression and treatment are lacking. We aim to image in vivo collagen in preclinical melanoma models during immunotherapy and quantify the collagen phenotype in treated and control mice. Second-harmonic generation imaging of collagen was performed in mouse melanoma tumors in vivo over a treatment time course. Animals were treated with a curative radiation and immunotherapy combination. Collagen morphology was quantified over time at an image and single-fiber level using CurveAlign and CT-FIRE software. In immunotherapy-treated mice, collagen was reorganized toward a healthy phenotype, including shorter, wider, curlier collagen fibers, with modestly higher collagen density. Temporally, collagen fiber straightness and length changed late in treatment (days 9 and 12), while width and density changed early (day 6) compared with control mice. Single-fiber collagen features calculated in CT-FIRE were the most sensitive to the changes among treatment groups compared with bulk collagen features. Quantitative second-harmonic generation imaging can provide insight into collagen dynamics in vivo during immunotherapy, with key implications in improving immunotherapy response in melanoma and other cancers.

Antibody-displaying extracellular vesicles for targeted cancer therapy.

Extracellular vesicles (EVs) function as natural delivery vectors and mediators of biological signals across tissues. Here, by leveraging these functionalities, we show that EVs decorated with an antibody-binding moiety specific for the fragment crystallizable (Fc) domain can be used as a modular delivery system for targeted cancer therapy. The Fc-EVs can be decorated with different types of immunoglobulin G antibody and thus be targeted to virtually any tissue of interest. Following optimization of the engineered EVs by screening Fc-binding and EV-sorting moieties, we show the targeting of EVs to cancer cells displaying the human epidermal receptor 2 or the programmed-death ligand 1, as well as lower tumour burden and extended survival of mice with subcutaneous melanoma tumours when systemically injected with EVs displaying an antibody for the programmed-death ligand 1 and loaded with the chemotherapeutic doxorubicin. EVs with Fc-binding domains may be adapted to display other Fc-fused proteins, bispecific antibodies and antibody-drug conjugates.

B- Mode Ultrasonography of Ocular Abnormalities in Dogs

Background: Ultrasonography is a simple, safe and non-invasive method to examine the internal structures of eye in case of opacity of otherwise clear ocular medium like cornea, aqueous, lens, and vitreous. Methods: 123 dogs with ocular abnormalities from March 2021 to October 2022, presented to the Division of Veterinary Surgery and Radiology were included in this study. All of the animals underwent a thorough ophthalmic examination along with B-scan ultrasonography of both the eyes using a 7.5 MHz linear probe. Result: Ultrasonography revealed thin hyperechoic lines and a thin hyperechoic rim of the lens, indicating early cataract changes and cortical cataract, respectively. Sixty-two dogs were found to be affected by cataract; 20 dogs were affected by the disease Phthisis bulbi; 16 dogs had a complete retinal detachment showing a typical “morning glory” sign; 10 dogs had vitreous haemorrhage; 6 dogs had a damaged eye with lens dislocation; and 5 dogs had choroidal melanoma and intraocular tumours in 4 dogs out of 123 observed dogs. Further, out of 62 cataract cases, 16 dogs were affected by cortical cataracts, 41 had nuclear cataracts, and 5 dogs were affected by morgagnian cataracts. Therefore, B-scan ultrasonography of the eye was a quick, safe, and accurate way to examine the pathology, especially when opaque media inhibit direct examination or when exophthalmos is evident and the normal anatomy of the eye.

O14 Monocytes and macrophages in the melanoma tumour microenvironment express Fc receptors which can be engaged with monoclonal antibodies of different isotypes

Abstract Introduction and aims Melanoma is the deadliest form of skin cancer and has an increasing worldwide incidence. It is well established that the melanoma tumour microenvironment (TME) has a large immune cell infiltrate, including a prominent monocytic compartment. Monocytic cells within the TME support melanoma growth, survival and metastasis. Contrastingly, such cells can be stimulated to promote tumour killing when engaged with monoclonal antibodies (mAbs) against cancer antigens, owing to their expression of multiple Fc receptors (FcRs). However, little is known about the monocytic subsets present within melanoma, the FcRs they express and how engaging their FcRs may influence function. Methods Flow cytometry on peripheral monocytes isolated from patients with melanoma and healthy volunteers enabled the characterization of cell surface markers. Next, publicly available single-cell RNA-Seq datasets were analysed to explore the transcriptome of melanoma-associated macrophages and these phenotypes were recapitulated in vitro. Finally, monocytes and macrophages were cocultured with melanoma cells, with or without the addition of mAbs against a melanoma antigen, in order to assess the effect of FcR crosslinking on monocyte and macrophage phenotype and function. Results Circulating monocytes in patients with melanoma feature an inhibitory phenotype, and express multiple FcRs, including Fcε and Fcγ receptors, which could be targeted with mAbs of multiple isotypes. Secondly, monocytic cells within the melanoma TME express protumour genes, including metalloproteinases and angiogenic factors. However, FcR expression suggests that tumour-promoting subsets can be targeted with mAbs. Finally, in ex vivo cocultures with melanoma cells, the FcRs of both human monocytes and macrophages are able to engage antimelanoma mAbs of multiple isotypes, inducing differential phenotype change. This is demonstrated by the upregulation of activation markers and costimulatory cell surface markers. Conclusions Together, these data suggest that tumour-promoting monocytic cells within the melanoma TME can be engaged and harnessed using different isotypes of mAbs targeting melanoma.

Diagnosis of Melanoma with 61Cu-Labeled PET Tracer.

Until the recent years, substances containing radioactive 61Cu were strongly considered as potential positron-emitting radiopharmaceuticals for use in positron emission tomography (PET) applications; however, due to their suitably long half-life, and generator-independent and cost-effective production, they seem to be economically viable for human imaging. Since malignant melanoma (MM) is a major public health problem, its early diagnosis is a crucial contributor to long-term survival, which can be achieved using radiolabeled α-melanocyte-stimulating hormone analog NAPamide derivatives. Here, we report on the physicochemical features of a new CB-15aneN5-based Cu(II) complex ([Cu(KFTGdiac)]-) and the ex vivo and in vivo characterization of its NAPamide conjugate. The rigid chelate possesses prompt complex formation and suitable inertness (t1/2 = 18.4 min in 5.0 M HCl at 50 °C), as well as excellent features in the diagnosis of B16-F10 melanoma tumors (T/M(SUVs) (in vivo): 12.7, %ID/g: 6.6 ± 0.3, T/M (ex vivo): 22).

Preclinical evaluation of MC1R targeting theranostic pair [155Tb]Tb-crown-αMSH and [161Tb]Tb-crown-αMSH

BackgroundTargeted radionuclide therapy is established as a highly effective strategy for the treatment of metastatic tumors; however, the co-development of suitable imaging companions to therapy remains significant challenge. Theranostic isotopes of terbium (149Tb, 152Tb, 155Tb, 161Tb) have the potential to provide chemically identical radionuclidic pairs, which collectively encompass all modes of nuclear decay relevant to nuclear medicine. Herein, we report the first radiochemistry and preclinical studies involving 155Tb- and 161Tb-labeled crown-αMSH, a small peptide-based bioconjugate suitable for targeting melanoma. Methods155Tb was produced via proton induced spallation of Ta targets using the isotope separation and acceleration facility at TRIUMF with isotope separation on-line (ISAC/ISOL). The radiolabeling characteristics of crown-αMSH with 155Tb and/or 161Tb were evaluated by concentration-dependence radiolabeling studies, and radio-HPLC stability studies. LogD7.4 measurements were obtained for [161Tb]Tb-crown-αMSH. Competitive binding assays were undertaken to determine the inhibition constant for [natTb]Tb-crown-αMSH in B16-F10 cells. Pre-clinical biodistribution and SPECT/CT imaging studies of 155Tb and 161Tb labeled crown-αMSH were undertaken in male C57Bl/6 J mice bearing B16-F10 melanoma tumors to evaluate tumor specific uptake and imaging potential for each radionuclide. ResultsQuantitative radiolabeling of crown-αMSH with [155Tb]Tb3+ and [161Tb]Tb3+ was demonstrated under mild conditions (RT, 10 min) and low chelator concentrations; achieving high molar activities (23–29 MBq/nmol). Radio-HPLC studies showed [161Tb]Tb-crown-αMSH maintains excellent radiochemical purity in human serum, while gradual metabolic degradation is observed in mouse serum. Competitive binding assays showed the high affinity of [natTb]Tb-crown-αMSH toward MC1R. Two different methods for preparation of the [155Tb]Tb-crown-αMSH radiotracer were investigated and the impacts on the biodistribution profile in tumor bearing mice is compared. Preclinical in vivo studies of 155Tb- and 161Tb- labeled crown-αMSH were performed in parallel, in mice bearing B16-F10 tumors; where the biodistribution results showed similar tumor specific uptake (6.06–7.44 %IA/g at 2 h pi) and very low uptake in nontarget organs. These results were further corroborated through a series of single-photon emission computed tomography (SPECT) studies, with [155Tb]Tb-crown-αMSH and [161Tb]Tb-crown-αMSH showing comparable uptake profiles and excellent image contrast. ConclusionsCollectively, our studies highlight the promising characteristics of [155Tb]Tb-crown-αMSH and [161Tb]Tb-crown-αMSH as theranostic pair for nuclear imaging (155Tb) and radionuclide therapy (161Tb).

Characterization of innate lymphoid cell subsets infiltrating melanoma and epithelial ovarian tumors

ABSTRACT The innate lymphoid cell (ILC) family is composed of heterogeneous innate effector and helper immune cells that preferentially reside in tissues where they promote tissue homeostasis. In cancer, they have been implicated in driving both pro- and anti-tumor responses. This apparent dichotomy highlights the need to better understand differences in the ILC composition and phenotype within different tumor types that could drive seemingly opposite anti-tumor responses. Here, we characterized the frequency and phenotype of various ILC subsets in melanoma metastases and primary epithelial ovarian tumors. We observed high PD-1 expression on ILC subsets isolated from epithelial ovarian tumor samples, while ILC populations in melanoma samples express higher levels of LAG-3. In addition, we found that the frequency of cytotoxic ILCs and NKp46+ILC3 in tumors positively correlates with monocytic cells and conventional type 2 dendritic cells, revealing potentially new interconnected immune cell subsets in the tumor microenvironment. Consequently, these observations may have direct relevance to tumor microenvironment composition and how ILC subset may influence anti-tumor immunity.

Long-term combined blockade of CXCR4 and PD-L1 with in vivo reassembly for intensive tumor interference

Negative immunoregulatory signal (PD-L1, CXCR4, et al.) and weak immunogenicity elicited immune system failing to detect and destroy cancerous cells. CXCR4 blockade promoted T cell tumor infiltration and increased tumor sensitivity to anti-PD-L1 therapy. Here, pH-responsive reassembled nanomaterials were constructed with anti-PD-L1 peptide and CXCR4 antagonists grafting (APAB), synergized with photothermal therapy for melanoma and breast tumor interference. The self-assembled APAB nanoparticles accumulated in the tumor and rapidly transformed into nanofibers in response to the acidic tumor microenvironment, leading to the exposure of grafted therapeutic agents. APAB enabling to reassemble around tumor cells and remained stable for over 96 h due to the aggregation induced retention (AIR) effect, led to long-term efficiently combined PD-L1 and CXCR4 blockade. Photothermal efficiency (ICG) induced immunogenic cell death (ICD) of tumor cells so as to effectively improve the immunogenicity. The combined therapy (ICG@APAB) could effectively inhibit the growth of primary tumor (∼83.52%) and distant tumor (∼76.24%) in melanoma-bearing mice, and significantly (p < 0.05) prolong the survival time over 42 days. The inhibition assay on tumor metastasis in 4 T1 model mice exhibited ICG@APAB almostly suppressed the occurrence of lung metastases and the expression levels of CD31, MMP-9 and VEGF in tumor decreased by 82.26%, 90.45% and 41.54%, respectively. The in vivo reassembly strategy will offer novel perspectives benefical future immunotherapies and push development of combined therapeutics into clinical settings.

Identification and characterization of a new potent inhibitor targeting CtBP1/BARS in melanoma cells

BackgroundThe C-terminal-binding protein 1/brefeldin A ADP-ribosylation substrate (CtBP1/BARS) acts both as an oncogenic transcriptional co-repressor and as a fission inducing protein required for membrane trafficking and Golgi complex partitioning during mitosis, hence for mitotic entry. CtBP1/BARS overexpression, in multiple cancers, has pro-tumorigenic functions regulating gene networks associated with “cancer hallmarks” and malignant behavior including: increased cell survival, proliferation, migration/invasion, epithelial-mesenchymal transition (EMT).Structurally, CtBP1/BARS belongs to the hydroxyacid-dehydrogenase family and possesses a NAD(H)-binding Rossmann fold, which, depending on ligands bound, controls the oligomerization of CtBP1/BARS and, in turn, its cellular functions.Here, we proposed to target the CtBP1/BARS Rossmann fold with small molecules as selective inhibitors of mitotic entry and pro-tumoral transcriptional activities.MethodsStructured-based screening of drug databases at different development stages was applied to discover novel ligands targeting the Rossmann fold. Among these identified ligands, N-(3,4-dichlorophenyl)-4-{[(4-nitrophenyl)carbamoyl]amino}benzenesulfonamide, called Comp.11, was selected for further analysis. Fluorescence spectroscopy, isothermal calorimetry, computational modelling and site-directed mutagenesis were employed to define the binding of Comp.11 to the Rossmann fold. Effects of Comp.11 on the oligomerization state, protein partners binding and pro-tumoral activities were evaluated by size-exclusion chromatography, pull-down, membrane transport and mitotic entry assays, Flow cytometry, quantitative real-time PCR, motility/invasion, and colony assays in A375MM and B16F10 melanoma cell lines. Effects of Comp.11 on tumor growth in vivo were analyzed in mouse tumor model.ResultsWe identify Comp.11 as a new, potent and selective inhibitor of CtBP1/BARS (but not CtBP2). Comp.11 directly binds to the CtBP1/BARS Rossmann fold affecting the oligomerization state of the protein (unlike other known CtBPs inhibitors), which, in turn, hinders interactions with relevant partners, resulting in the inhibition of both CtBP1/BARS cellular functions: i) membrane fission, with block of mitotic entry and cellular secretion; and ii) transcriptional pro-tumoral effects with significantly hampered proliferation, EMT, migration/invasion, and colony-forming capabilities. The combination of these effects impairs melanoma tumor growth in mouse models. ConclusionsThis study identifies a potent and selective inhibitor of CtBP1/BARS active in cellular and melanoma animal models revealing new opportunities to study the role of CtBP1/BARS in tumor biology and to develop novel melanoma treatments.

Aggregation of melanoma tumour site within Western Australian families

BackgroundEvidence is emerging that melanoma has distinct aetiologic pathways and subtypes, characterized by factors like anatomic site of the tumour. To explore genetic influences on anatomic subtypes, we examined the extent to which melanomas in first-degree relatives shared the same body site of occurrence. MethodsPopulation-level linked data was used to identify the study population of over 1.5 million individuals born in Western Australia between 1945 and 2014, and their first-degree relatives. There were 1009 pairs of invasive tumours from 677 family pairs, each categorised by anatomic site. Greater than expected representation of site-concordant pairs would suggest the presence of genetic factors that predispose individuals to site-specific melanoma. ResultsComparing observed versus expected totals, we observed a modest increase in site concordance for invasive head/neck and truncal tumours (P=0.02). A corresponding analysis including in situ tumours showed a similar concordance (P=0.05). No further evidence of concordance was observed when stratified by sex. ConclusionIn conclusion, modest evidence of aggregation was observed but with inconsistent patterns between sites. Results suggest that further investigation into the familial aggregation of melanoma by tumour site is warranted, with the inclusion of genetic data in order to disentangle the relative contributions of genetic and environmental factors.

CAR T cells against TRP1 significantly reduce melanoma growth in vitro and in vivo

Abstract CAR T cells have shown great efficacy for patients with liquid malignancies. However, CAR T cell treatments have had limited efficacy in patients with solid lesions, such as melanoma. One reason is the lack of suitable targets specific to the tumor antigen, which also do not cause toxicity. TRP1 is abundantly expressed in melanoma cells as well as in healthy melanocytes. While targeting healthy melanocytes may cause vitiligo, that condition is not life threatening. Previous work shows monoclonal antibodies against TRP1 reject melanoma tumors and lung metastases. Therefore, we designed a CAR with an scFv against human TRP1 along with 41BB and CD3z costimulation. When we examined CAR T cell cytotoxicity in vitro, we found a significant reduction in melanoma target cells after 48hrs co-culture with CAR T cells at 10:1 and 5:1 E:T ratios compared to untransduced (UT) cells. CAR T cell cytokine production after melanoma co-culture also showed significantly higher IFNg compared to UT cells. To examine CAR T cell efficacy in vivo, we challenged NSG mice intradermally with melanoma tumor cells. Four days after the tumor challenge, mice were given CAR T or UT cells by tail vein injection. We found that mice given anti-TRP1 CAR T cells had significantly reduced tumor area by day 10 and had significantly increased survival compared to mice given UT cells. This work shows that TRP1 can be effectively targeted by CAR T cells and increase the survival of mice with melanoma.

SIGLEC-3 (CD33) serves as an effective target in tumor progression

Abstract Human CD33 (Siglec-3) possesses an immune-receptor tyrosine-based inhibition motif (ITIM), which recruits Src homology 2 (SH2) containing phosphatases (SHP-1/2) and inositol phosphatase (SHIP) and exerts inhibitory effects. The structure and downstream signaling of CD33 bear similarity to programmed cell death protein-1 (PD-1), a promising target in cancer immune therapy. Previous studies indicate that CD33 serves as a therapeutic target in acute myeloid leukemia (AML), additionally, CD33 also acts as a prevalent surface marker of human myeloid-derived suppressor cells (MDSCs). According to the inhibitory signaling upon CD33 activation, CD33 may participate in tumor progression and the regulatory role of CD33 in solid tumors is still unclear. To investigate whether CD33 influences cancer progression, we established a melanoma tumor (B16F10) mouse model in monocyte/macrophage-specific human CD33 transgenic mice (hCD33 Tg mice, Cx3cr1cre/-hCD33M+/-). Compared to wild-type mice (WT), tumor growth and mortality were larger and higher in CD33 Tg mice. Moreover, an antagonistic anti-hCD33 monoclonal antibody (clone 4L3-46) treatment successfully attenuated tumor growth in hCD33 Tg mice and led to a restructuring of the infiltrating MDSCs population. These results indicate that human CD33 contributes to the advancement of tumors, and the blockade of CD33 represents a promising strategy in tumor therapy.

Endogenous ICOS signaling supports Th17 therapy efficacy

Abstract Objective: We sought to determine the mechanism by which antigen-specific Th17 cells are able to clear melanoma tumors more effectively than their Th1 counterparts and to expand on the role of ICOS in the success of Th17 therapy. Methods: Antigen-specific TRP-1 CD4+ T cells were polarized to Th17 or Th1 phenotypes and were adoptively transferred into mice bearing B16F10 melanoma. The role of inducible costimulatory molecule (ICOS) in this therapy response was evaluated by antibody blockade and genetic deletion. RNA-Sequencing, flow cytometry, and tumor growth measurements were additionally used to assess differences when ICOS was blocked or not. Summary of Results: ICOS is important for the efficacy of Th17 therapy in mice with established melanoma as when blocking ICOS signaling via antibody or genetic means, both antitumor activity and survival was diminished. By assessing the phenotype of both infused and host lymphocytes, we found that B cell proliferation and the engraftment of transferred cells decreased in the mice blocked of ICOS signaling. I also found that ICOS signaling appears to be important early on after Th17 cells infusion, as blocking ICOS at early but not later time points compromised antitumor immunity. Conclusions: ICOS is important for long-term survival and antitumor activity of mice treated with Th17 cells targeting melanoma.

Bromodomain inhibition targeting BPTF in the treatment of melanoma and other solid tumors.

Epigenetic mechanisms have been shown to play an important role in the development of cancer. These include the activation of chromatin remodeling factors in various malignancies, including bromodomain plant homeodomain (PHD) finger transcription factor (BPTF), the largest component of the human nucleosome remodeling factor (NURF). In the last few years, BPTF has been identified as a pro-tumorigenic factor in melanoma, stimulated by research into the molecular mechanisms underlying BPTF function. Developing therapy targeting the BPTF bromodomain would represent a significant advance. Melanoma therapy has been revolutionized by the efficacy of immunotherapeutic and targeted strategies, but the development of drug resistance calls for alternative therapeutic approaches. Recent work has shown both a biomarker as well as functional role for BPTF in melanoma progression and as a possible target for its therapy. BPTF was shown to stimulate the mitogen-activated protein kinase pathway, which is targeted by selective BRAF inhibitors. The advent of small molecule inhibitors that target bromodomain motifs has shown that bromodomains are druggable. By combining the bromodomain inhibitor bromosporine with existing treatments that target mutant BRAF, BPTF targeting has emerged as a novel and promising therapeutic approach for metastatic melanoma. This article summarizes the functional role of BPTF in tumor progression, reviews the clinical experience to date with bromodomain inhibitors, and discusses the promise of BPTF targeting in melanoma and other solid tumors.

Electrospun nanofibrous scaffolds as a platform to reduce melanoma tumour growth, recurrence, and promote post-resection wound repair

Wound healing following skin tumour surgery still remains a major challenge. To address this issue, polysaccharide-loaded nanofibrous mats have been engineered as skin patches on the wound site to improve wound healing while simultaneously eliminating residual cancer cells which may cause cancer relapse. The marine derived polysaccharides kappa-carrageenan (KCG) and fucoidan (FUC) were blended with polydioxanone (PDX) nanofibers due to their inherent anti-cancer activity conferred by the sulphate groups as well as their immunomodulatory properties which can reduce inflammation resulting in accelerated wound healing. KCG and FUC were released sustainably from the blend nanofibers via the Korsmeyer-Peppas kinetics. MTT assays, live/dead staining and SEM images demonstrated the toxicity of KCG and FUC towards skin cancer MP 41 cells. In addition, MP 41 cells showed reduced metastatic potential when grown on KCG or FUC containing mats. Both KCG and FUC were non- cytotoxic to healthy L 929 fibroblast cells. In vivo studies on healthy Wistar rats confirmed the non-toxicity of the nanofibrous patches as well as their improved and scarless wound healing potential. In vivo studies on tumour xenograft model further showed a reduction of 7.15 % in tumour volume in only 4 days following application of the transdermal patch.

Melanoma-Derived DNA Polymerase Theta Variants Exhibit Altered DNA Polymerase Activity.

DNA polymerase θ (Pol θ or POLQ) is primarily involved in repairing double-stranded breaks in DNA through an alternative pathway known as microhomology-mediated end joining (MMEJ) or theta-mediated end joining (TMEJ). Unlike other DNA repair polymerases, Pol θ is thought to be highly error-prone yet critical for cell survival. We have identified several POLQ gene variants from human melanoma tumors that experience altered DNA polymerase activity, including a propensity for incorrect nucleotide selection and reduced polymerization rates compared to WT Pol θ. Variants are 30-fold less efficient at incorporating a nucleotide during repair and up to 70-fold less accurate at selecting the correct nucleotide opposite a templating base. This suggests that aberrant Pol θ has reduced DNA repair capabilities and may also contribute to increased mutagenesis. Moreover, the variants were identified in established tumors, suggesting that cancer cells may use mutated polymerases to promote metastasis and drug resistance.

Activation of the MEK/ERK Pathway Mediates the Inhibitory Effects of Silvestrol on Nasopharyngeal Carcinoma Cells via RAP1A, HK2, and GADD45A.

Nasopharyngeal carcinoma (NPC) is a malignant tumor associated with Epstein-Barr virus (EBV) infection. Chemoradiotherapy is the mainstream treatment for locally advanced NPC, and chemotherapeutic drugs are an indispensable part of NPC treatment. However, the toxic side-effects of chemotherapy drugs limit their therapeutic value, and new chemotherapy drugs are urgently needed for NPC. Silvestrol, an emerging natural plant anticancer molecule, has shown promising antitumor activity in breast cancer, melanoma, liver cancer, and other tumor types by promoting apoptosis in cancer cells to a greater extent than in normal cells. However, the effects of silvestrol on NPC and its possible molecular mechanisms have yet to be fully explored. Cell counting kit-8 (CCK-8), cell scratch, flow cytometry, 5-ethynyl-2'-deoxyuridine (EdU), and Western blot (WB) assays were used to evaluate the effects of silvestrol on the cell viability, cell cycle, apoptosis, and migration of NPC cells. RNA sequencing (RNA-Seq) was used to study the effect of extracellular signal-regulated kinase (ERK) inhibitors on the cell transcriptome, and immunohistochemistry (IHC) to assess protein expression levels in patient specimens. Silvestrol inhibited cell migration and DNA replication of NPC cells, while promoting the expression of cleaved caspase-3, apoptosis, and cell cycle arrest. Furthermore, silvestrol altered the level of ERK phosphorylation. The ERK-targeted inhibitor LY3214996 attenuated silvestrol-mediated inhibition of NPC cell proliferation but not migration. Analysis of RNA-Seq data and WB were used to identify and validate the downstream regulatory targets of silvestrol. Expression of GADD45A, RAP1A, and hexokinase-II (HK2) proteins was inhibited by silvestrol and LY3214996. Finally, IHC revealed that GADD45A, RAP1A, and HK2 protein expression was more abundant in cancer tissues than in non-tumor tissues. Silvestrol inhibits the proliferation of NPC cells by targeting ERK phosphorylation. However, the inhibition of NPC cell migration by silvestrol was independent of the Raf-MEK-ERK pathway. RAP1A, HK2, and GADD45A may be potential targets for the action of silvestrol.

RNA M6A modification shaping cutaneous melanoma tumor microenvironment and predicting immunotherapy response.

Recent years have seen rising mortality rates linked to cutaneous melanoma (SKCM), despite advances in immunotherapy. Understanding RNA N6-methyladenosine (M6A) significance in SKCM is crucial for prognosis, tumor microenvironment (TME), immune cell presence, and immunotherapy efficacy. We analyzed 23 M6A regulators using SKCM samples from TCGA and GEO databases, identifying three M6A modification patterns linked to TME cell infiltration. Principal component analysis (PCA) yielded an M6A score for individual tumors, utilizing patient gene expression profiles and CNV data from TCGA. M6A modification patterns play a crucial role in SKCM development and progression, influencing tumor attributes such as inflammatory stage, subtype, TME interstitial activity, and genetic mutations. The M6A score independently predicts patient outcomes and correlates with improved response to immunotherapy, validated across anti-PD-1 and anti-PD-L1 therapy cohorts. M6A modifications significantly impact the TME landscape, with the M6A score serving as a predictive marker for immunotherapy response. Integrating M6A-related information into clinical practice could revolutionize SKCM management and treatment strategies.