Alternative Options for Skin Cancer Therapy via Regulation of AKT and Related Signaling Pathways

Rosmarinic acid modulates purinergic signaling and induces apoptosis in melanoma cells

Cancer cases have increased worldwide. Cutaneous melanoma (CM), a highly metastatic skin cancer, largely contributes to global statistical cancer death data. Research has shown that rosmarinic acid (RA) is a promising phenolic compound with antineoplastic properties. Thus, we investigated the effects of RA on apoptosis-inducing in melanoma cells, purinergic signaling modulation, and cytokine levels. We treated SK-MEL-28 cells for 24 h with different concentrations of RA and assessed the apoptosis, CD39, CD73, and A2A expression, and cytokine levels. We found RA-induced apoptosis in melanoma cells. Regarding the purinergic system, we verified that RA downregulated the expression of CD73 and A2A, specially at high concentrations of treatment. Additionally, RA increased IL-6, IL-4, IL-10, IFN-γ, and TNF-α levels. Our in vitro results confirm RA's potential to be used to induce melanoma cell apoptosis, having CD73 and A2A as targets when reversion of immune suppression is desired. Further studies in animal models and clinical trials focusing on RA's modulation of purinergic signaling in melanoma are required.

Regulation of cancer progression by CK2: an emerging therapeutic target

Casein kinase II (CK2) is an enzyme with pleiotropic kinase activity that catalyzes the phosphorylation of lots of substrates, including STAT3, p53, JAK2, PTEN, RELA, and AKT, leading to the regulation of diabetes, cardiovascular diseases, angiogenesis, and tumor progression. CK2 is observed to have high expression in multiple types of cancer, which is associated with poor prognosis. CK2 holds significant importance in the intricate network of pathways involved in promoting cell proliferation, invasion, migration, apoptosis, and tumor growth by multiple pathways such as JAK2/STAT3, PI3K/AKT, ATF4/p21, and HSP90/Cdc37. In addition to the regulation of cancer progression, increasing evidence suggests that CK2 could regulate tumor immune responses by affecting immune cell activity in the tumor microenvironment resulting in the promotion of tumor immune escape. Therefore, inhibition of CK2 is initially proposed as a pivotal candidate for cancer treatment. In this review, we discussed the role of CK2 in cancer progression and tumor therapy.

Multifaceted approach toward mapping out the anticancer properties of small molecules via in vitro evaluation on melanoma and nonmelanoma skin cancer cells, and in silico target fishing

Melanoma and nonmelanoma skin cancers are among the most prevalent and most lethal forms of skin cancers. To identify new lead compounds with potential anticancer properties for further optimization, in vitro assays combined with in-silico target fishing and docking have been used to identify and further map out the antiproliferative and potential mode of action of molecules from a small library of compounds previously prepared in our laboratory. From screening these compounds in vitro against A375, SK-MEL-28, A431, and SCC-12 skin cancer cell lines, 35 displayed antiproliferative activities at the micromolar level, with the majority being primarily potent against the A431 and SCC-12 squamous carcinoma cell lines. The most active compounds 11 (A431: IC50  = 5.0 μM, SCC-12: IC50  = 2.9 μM, SKMEL-28: IC50  = 4.9 μM, A375: IC50  = 6.7 μM) and 13 (A431: IC50  = 5.0 μM, SCC-12: IC50  = 3.3 μM, SKMEL-28: IC50  = 13.8 μM, A375: IC50  = 17.1 μM), significantly and dose-dependently induced apoptosis of SCC-12 and SK-MEL-28 cells, as evidenced by the suppression of Bcl-2 and upregulation of Bax, cleaved caspase-3, caspase-9, and PARP protein expression levels. Both agents significantly reduced scratch wound healing, colony formation, and expression levels of deregulated cancer molecular targets including RSK/Akt/ERK1/2 and S6K1. In silico target prediction and docking studies using the SwissTargetPrediction web-based tool suggested that CDK8, CLK4, nuclear receptor ROR, tyrosine protein-kinase Fyn/LCK, ROCK1/2, and PARP, all of which are dysregulated in skin cancers, might be prospective targets for the two most active compounds. Further validation of these targets by western blot analyses, revealed that ROCK/Fyn and its associated Hedgehog (Hh) pathways were downregulated or modulated by the two lead compounds. In aggregate, these results provide a strong framework for further validation of the observed activities and the development of a more comprehensive structure-activity relationship through the preparation and biological evaluation of analogs.

Synthesis, in silico modelling, and in vitro biological evaluation of substituted pyrazole derivatives as potential anti-skin cancer, anti-tyrosinase, and antioxidant agents

Twenty-five azole compounds (P1-P25) were synthesised using regioselective base-metal catalysed and microwave-assisted approaches, fully characterised by high-resolution mass spectrometry (HRMS), nuclear magnetic resonance (NMR), and infrared spectra (IR) analyses, and evaluated for anticancer, anti-tyrosinase, and anti-oxidant activities in silico and in vitro. P25 exhibited potent anticancer activity against cells of four skin cancer (SC) lines, with selectivity for melanoma (A375, SK-Mel-28) or non-melanoma (A431, SCC-12) SC cells over non-cancerous HaCaT-keratinocytes. Clonogenic, scratch-wound, and immunoblotting assay data were consistent with anti-proliferative results, expression profiling therewith implicating intrinsic and extrinsic apoptosis activation. In a mushroom tyrosinase inhibition assay, P14 was most potent among the compounds (half-maximal inhibitory concentration where 50% of cells are dead, IC50 15.9 μM), with activity greater than arbutin and kojic acid. Also, P6 exhibited noteworthy free radical-scavenging activity. Furthermore, in silico docking and absorption, distribution, metabolism, excretion, and toxicity (ADMET) simulations predicted prominent-phenotypic actives to engage diverse cancer/hyperpigmentation-related targets with relatively high affinities. Altogether, promising early-stage hits were identified - some with multiple activities - warranting further hit-to-lead optimisation chemistry with further biological evaluations, towards identifying new skin-cancer and skin-pigmentation renormalising agents.

Oncogenic DNA methyltransferase 1 activates the PI3K/AKT/mTOR signalling by blocking the binding of HSPB8 and BAG3 in melanoma

Abnormal DNA methylation has been observed in multiple malignancies, including melanoma. In this study, we initially noticed the overexpression of DNA methyltransferase 1 (DNMT1) in melanoma samples in bioinformatics analysis and, subsequently, validated it in the purchased melanoma cell lines. After treatment with short-hairpin RNAs or Decitabine (a DNA methylation inhibitor), silencing of DNMT1 was demonstrated to suppress cell viability and invasive and migratory potentials as well as to augment apoptosis and autophagy in melanoma cells. To further explore the downstream mechanisms, we revealed that DNMT1 inhibited HSPB8 expression through augmenting HSPB8 methylation, thereby suppressing the binding between HSPB8 and BAG3. Then, we elucidated through a series of gain- and loss- of function assays that the interplay of HSPB8 and BAG3 blocked the PI3K/AKT/mTOR pathway, thereby repressing the malignant phenotypes of melanoma cells and contributing to melanoma cell apoptosis and autophagy. We further established a mouse model of melanoma and substantiated that DNMT1 enhanced the in vivo tumorigenesis of melanoma cells via activation of the PI3K/AKT/mTOR pathway through repressing the binding between HSPB8 and BAG3. Taken together, our data supported that DNMT1 repressed the binding between HSPB8 and BAG3 and activated the PI3K/AKT/mTOR pathway, thus playing a tumour-promoting role in melanoma.

Licochalcone D Inhibits Skin Epidermal Cells Transformation through the Regulation of AKT Signaling Pathways

Cell transformation induced by epidermal growth factor (EGF) and 12-O-tetradecanoylphorbol-13-acetate (TPA) is a critical event in cancer initiation and progression, and understanding the underlying mechanisms is essential for the development of new therapeutic strategies. Licorice extract contains various bioactive compounds, which have been reported to have anticancer and anti-inflammatory effects. This study investigated the cancer preventive efficacy of licochalcone D (LicoD), a chalcone derivative in licorice extract, in EGF and TPA-induced transformed skin keratinocyte cells. LicoD effectively suppressed EGF-induced cell proliferation and anchorage-independent colony growth. EGF and TPA promoted the S phase of cell cycle, while LicoD treatment caused G1 phase arrest and down-regulated cyclin D1 and up-regulated p21 expression associated with the G1 phase. LicoD also induced apoptosis and increased apoptosis-related proteins such as cleaved-caspase-3, cleaved-caspase-7, and Bax (Bcl-2-associated X protein). We further investigated the effect of LicoD on the AKT signaling pathway involved in various cellular processes and found decreased p-AKT, p-GSK3β, and p-NFκB expression. Treatment with MK-2206, an AKT pharmacological inhibitor, suppressed EGF-induced cell proliferation and transformed colony growth. In conclusion, this study demonstrated the potential of LicoD as a preventive agent for skin carcinogenesis.

Exploring Nanocarriers as Treatment Modalities for Skin Cancer

Cancer is a progressive disease of multi-factorial origin that has risen worldwide, probably due to changes in lifestyle, food intake, and environmental changes as some of the reasons. Skin cancer can be classified into melanomas from melanocytes and nonmelanoma skin cancer (NMSC) from the epidermally-derived cell. Together it constitutes about 95% of skin cancer. Basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (CSCC) are creditworthy of 99% of NMSC due to the limited accessibility of conventional formulations in skin cancer cells of having multiple obstacles in treatment reply to this therapeutic regime. Despite this, it often encounters erratic bioavailability and absorption to the target. Nanoparticles developed through nanotechnology platforms could be the better topical skin cancer therapy option. To improve the topical delivery, the nano-sized delivery system is appropriate as it fuses with the cutaneous layer and fluidized membrane; thus, the deeper penetration of therapeutics could be possible to reach the target spot. This review briefly outlooks the various nanoparticle preparations, i.e., liposomes, niosomes, ethosomes, transferosomes, transethosomes, nanoemulsions, and nanoparticles technologies tested into skin cancer and impede their progress tend to concentrate in the skin layers. Nanocarriers have proved that they can considerably boost medication bioavailability, lowering the frequency of dosage and reducing the toxicity associated with high doses of the medication.

New Sesquiterpene Glycosides from the Flowers of Aster koraiensis and Their Inhibition Activities on EGF- and TPA-Induced Cell Transformation

In total, four new eudesmane-type sesquiterpene glycosides, askoseosides A-D (1-4), and 18 known compounds (5-22) were isolated from the flowers of Aster koraiensis via chromatographic techniques. Chemical structures of the isolated compounds were identified by spectroscopic/spectrometric methods, including NMR and HRESIMS, and the absolute configuration of the new compounds (1 and 2) was performed by electronic circular dichroism (ECD) studies. Further, the anticancer activities of the isolated compounds (1-22) were evaluated using the epidermal growth factor (EGF)-induced as well as the 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced cell transformation assay. Among the 22 compounds, compounds 4, 9, 11, 13-15, 17, 18, and 22 significantly inhibited both EGF- and TPA-induced colony growth. In particular, askoseoside D (4, EGF: 57.8%; TPA: 67.1%), apigenin (9, EGF: 88.6%; TPA: 80.2%), apigenin-7-O-β-d-glucuronopyranoside (14, EGF: 79.2%; TPA: 70.7%), and 1-(3',4'-dihydroxycinnamoyl) cyclopentane-2,3-diol (22, EGF: 60.0%; TPA: 72.1%) showed higher potent activities.

Black Tea Extract, via Modulation of TGF-β Pathway, Prevents Inorganic Arsenic-induced Development of Squamous Cell Carcinoma of the Skin in Swiss Albino Mice

Chronic exposure to inorganic arsenic (iAs) elevates reactive oxygen species (ROS) generation and up-regulates TGF-β signalling. This promotes induction of epithelial to mesenchymal transition (EMT) and causes the development of squamous cell carcinoma (SCC) of skin. Black tea is a popular beverage worldwide and an effective antioxidant. Chemopreventive potential of black tea extract (BTE) against iAs induced carcinogenicity has been explored here. The study aims to investigate the role of BTE in prevention of iAs-induced SCC of skin in Swiss albino mice via the modulation of TGF-β signalling and EMT. Mice were divided into (1) control, (2) iAs, (3) iAs+BTE, and (4) BTE groups and were administered iAs and BTE alone, or in combination for 330 days. Histological studies were performed to assess development of SCC. ROS generation was estimated by flowcytometry. Expression of TGF-β and downstream proteins belonging to suppressor of mothers against decapentaplegic (Smad), phosphoinositide-3-kinase (PI3K)-protein kinase B (AKT) and mitogen-activated protein kinase (MAPK) pathways was assessed by immunoblotting. Expression of EMT markers was evaluated by immunoblotting, immunohistochemistry and semi-quantitative reverse transcriptase-PCR. After 330 days of iAs treatment, development of invasive SCC of skin probably due to excess ROS generation, elevation of TGF-β, downregulation of the Smad pathway, upregulation of PI3K-AKT and MAPK signalling molecules and induction of EMT was observed. All these modulations were found to be reversed by BTE, which inhibits iAs induced SCC of skin by quenching excess ROS, promoting Smad mediated TGF-β signalling, downregulating signalling intermediates of PI3K-AKT and MAPK pathways and inhibiting EMT.

Echinatin induces reactive oxygen species-mediated apoptosis via JNK/p38 MAPK signaling pathway in colorectal cancer cells

Colorectal cancer (CRC) is a very common and deadly cancer worldwide, and oxaliplatin is used as first-line chemotherapy. However, resistance usually develops, limiting treatment. Echinatin (Ech) is the main component of licorice and exhibits various therapeutic effects on inflammation-mediated diseases and cancer, ischemia/reperfusion, and liver injuries. The present study elucidated the underlying molecular mechanism of Ech-induced apoptosis in both oxaliplatin-sensitive (HT116 and HT29) and -resistant (HCT116-OxR and HT29-OxR) CRC cells. To evaluate the antiproliferative activities of Ech, we performed MTT and soft agar assays. Ech reduced viability, colony size, and numbers of CRC cells. The underlying molecular mechanisms were explored by various flow cytometry analyses. Ech-induced annexin-V stained cells, reactive oxygen species (ROS) generation, cell cycle arrest, JNK/p38 MAPK activation, endoplasmic reticulum (ER) stress, mitochondrial membrane potential depolarization, and multi-caspase activity. In addition apoptosis-, cell cycle-, and ER stress-related protein levels were confirmed by western blotting. Moreover, we verified ROS-mediated cell death by treatment with inhibitors such as N-acetyl-L-cysteine, SP600125, and SB203580. Taken together, Ech exhibits anticancer activity in oxaliplatin-sensitive and -resistant CRCs by inducing ROS-mediated apoptosis through the JNK/p38 MAPK signaling pathway. This is the first study to show that Ech has the potential to treat drug-resistant CRC, providing new directions for therapeutic strategies targeting drug-resistant CRC.

Preclinical activities of Cassia tora Linn against aging-related diseases

Globally, an aging population is increasing, and aging is a natural physiological process and a major risk factor for all age-related diseases. It seriously threatens personal health and imposes a great economic burden. Therefore, there is a growing scientific interest in strategies for well-aging with prevention and treatment of age-related diseases. The seed, root, stem or leaves of Cassia tora Linn. are useful for anti-bacteria, anti-hyperlipidemia and anti-obesity due to its pharmacological activities such as anti-inflammation and anti-oxidant both in vitro and in vivo. Nevertheless, no clinical trials have been attempted so far, therefore here we would like to understand the current preclinical activities for aging-related disease models including cataract, metabolic dysfunction and neurodegeneration, then discuss their preparation for clinical trials and perspectives.

UBIAD1 and CoQ10 protect melanoma cells from lipid peroxidation-mediated cell death

Cutaneous melanoma is the deadliest type of skin cancer, although it accounts for a minority of all skin cancers. Oxidative stress is involved in all stages of melanomagenesis and cutaneous melanoma can sustain a much higher load of Reactive Oxygen Species (ROS) than normal tissues. Melanoma cells exploit specific antioxidant machinery to support redox homeostasis. The enzyme UBIA prenyltransferase domain-containing protein 1 (UBIAD1) is responsible for the biosynthesis of non-mitochondrial CoQ10 and plays an important role as antioxidant enzyme. Whether UBIAD1 is involved in melanoma progression has not been addressed, yet. Here, we provide evidence that UBIAD1 expression is associated with poor overall survival (OS) in human melanoma patients. Furthermore, UBIAD1 and CoQ10 levels are upregulated in melanoma cells with respect to melanocytes. We show that UBIAD1 and plasma membrane CoQ10 sustain melanoma cell survival and proliferation by preventing lipid peroxidation and cell death. Additionally, we show that the NAD(P)H Quinone Dehydrogenase 1 (NQO1), responsible for the 2-electron reduction of CoQ10 on plasma membranes, acts downstream of UBIAD1 to support melanoma survival. By showing that the CoQ10-producing enzyme UBIAD1 counteracts oxidative stress and lipid peroxidation events in cutaneous melanoma, this work may open to new therapeutic investigations based on UBIAD1/CoQ10 loss to cure melanoma.

Costunolide suppresses melanoma growth via the AKT/mTOR pathway in vitro and in vivo

Melanoma is the most common type of skin cancer and its incidence is rapidly increasing. AKT, and its related signaling pathways, are highly activated in many cancers including lung, colon, and esophageal cancers. Costunolide (CTD) is a sesquiterpene lactone that has been reported to possess neuroprotective, anti-inflammatory, and anti-cancer properties. However, the target and mechanism underlying its efficacy in melanoma have not been identified. In this study, we elucidated the mechanism behind the anti-cancer effect of CTD in melanoma in vitro and in vivo by identifying CTD as an AKT inhibitor. We first verified that p-AKT and AKT are highly expressed in melanoma patient tissues and cell lines. CTD significantly inhibited the proliferation, migration, and invasion of melanoma cells including SK-MEL-5, SK-MEL-28, and A375 that are overexpressed p-AKT and AKT proteins. We investigated the mechanism of CTD using a computational docking modeling, pull-down, and site directed mutagenesis assay. CTD directly bound to AKT thereby arresting cell cycle at the G1 phase, and inducing the apoptosis of melanoma cells. In addition, CTD regulated the G1 phase and apoptosis biomarkers, and inhibited the expression of AKT/mTOR/GSK3b/p70S6K/4EBP cascade proteins. After reducing AKT expression in melanoma cells, cell growth was significantly decreased and CTD did not showed further inhibitory effects. Furthermore, CTD administration suppressed tumor growth and weight in cell-derived xenograft mice models in vivo without body weight loss and inhibited the expression of Ki-67, p-AKT, and p70S6K in tumor tissues. In summary, our study implied that CTD inhibited melanoma progression in vitro and in vivo. In this study, we reported that CTD could affect melanoma growth by targeting AKT. Therefore, CTD has considerable potential as a drug for melanoma therapy.