Human Epidermoid Carcinoma Research Articles

Hypoxia-activated dissociation of heteroleptic cobalt(III) complexes with functionalized 2,2'-bipyridines and a model anticancer drug esculetin.

A low oxygen level in solid tumors is behind the modern concept of selective chemotherapy by hypoxia-activated prodrugs, such as heteroleptic complexes of transition metals (cobalt(III), iron(III) or platinum(IV)) with bi- or tetradentate ligands and an anticancer drug molecule as a co-ligand. A series of new cobalt(III) complexes [Co(LR)2(esc)]ClO4 with esculetin (6,7-dihydroxycoumarin) and 2,2'-bipyridines (2,2'-bipy) functionalized by different substituents R were probed in the hypoxia-activated delivery of this model anticancer drug. Their combined study by cyclic voltammetry and in situ NMR spectroscopy allowed identifying linear correlations of the electrochemical reduction potentials and the rate of the hypoxia-activated dissociation of [Co(LR)2(esc)]ClO4 with the Hammett constants of the substituents in 2,2'-bipy ligands. The latter, therefore, should be decorated with the most electron-withdrawing groups (unless they preclude the formation of a heteroleptic complex) to promote the drug release and increase the anticancer activity towards, e.g., human epidermoid carcinoma A431.These correlations can be transferred to other types of bi- or tetradentate ligands, thereby paving the way towards the molecular design of cobalt complexes as prodrugs for hypoxia-activated anticancer drug delivery with high therapeutic efficiency.

Exploring the anticancer activities of Sulfur and magnesium oxide through integration of deep learning and fuzzy rough set analyses based on the features of Vidarabine alkaloid

Drug discovery and development is a challenging and time-consuming process. Laboratory experiments conducted on Vidarabine showed IC50 6.97 µg∕mL, 25.78 µg∕mL, and ˃ 100 µg∕mL against non-small Lung cancer (A-549), Human Melanoma (A-375), and Human epidermoid Skin carcinoma (skin/epidermis) (A-431) respectively. To address these challenges, this paper presents an Artificial Intelligence (AI) model that combines the capabilities of Deep Learning (DL) to identify potential new drug candidates, Fuzzy Rough Set (FRS) theory to determine the most important chemical compound features, Explainable Artificial Intelligence (XAI) to explain the features’ importance in the last layer, and medicinal chemistry to rediscover anticancer drugs based on natural products like Vidarabine. The proposed model aims to identify potential new drug candidates. By analyzing the results from laboratory experiments on Vidarabine, the model identifies Sulfur and magnesium oxide (MgO) as new potential anticancer agents. The proposed model selected Sulfur and MgO based on Interpreting their promising features, and further laboratory experiments were conducted to validate the model’s predictions. The results demonstrated that, while Vidarabine was inactive against the A-431 cell line (IC50 ˃ 100 µg∕mL), Sulfur and MgO exhibited significant anticancer activity (IC50 4.55 and 17.29 µg/ml respectively). Sulfur displayed strong activity against A-549 and A-375 cell lines (IC50 3.06 and 1.86 µg/ml respectively) better than Vidarabine (IC50 6.97 and 25.78 µg/ml respectively). However, MgO showed weaker activity against these two cell lines. This paper emphasizes the importance of uncovering hidden chemical features that may not be discernible without the assistance of AI. This highlights the ability of AI to discover novel compounds with therapeutic potential, which can significantly impact the field of drug discovery. The promising anticancer activity exhibited by Sulfur and MgO warrants further preclinical studies.

Synthesis and Evaluation of Cytotoxic Activity of RuCp(II) Complexes Bearing (Iso)nicotinic Acid Based Ligands.

Cancer remains one of the major challenges of our century. Organometallic ruthenium complexes are gaining recognition as a highly promising group of compounds in the development of cancer treatments. Building on the auspicious results obtained for [Ru(η5-C5H5)(PPh3)(bipy)][CF3SO3] (TM34), our focus has shifted to examining the effects of incorporating bioactive ligands into the TM34 framework, particularly within the cyclopentadienyl ring. In this study, we report the synthesis and characterization of two new ruthenium(II) complexes with the general formula [Ru(η5-C5H4CCH3=R)(PPh3)(bipy)][CF3SO3], where R represents a nicotinic acid derivative (NNHCO(py-3-yl)) (1) or an isoniazid derivative (NNHCO(py-4-yl)) (2). The complexes were fully characterized using a combination of spectroscopic techniques and computational analysis, revealing the presence of E/Z-hydrazone isomerism. Stability studies confirmed the robustness of both complexes in biological media, with compound 1 maintaining good stability in buffer solutions mimicking physiological (pH 7.4) and tumor-like (pH 6.8) environments. The cytotoxicity of the complexes was evaluated in vitro in several human cancer cell lines, namely melanoma (A375), alveolar adenocarcinoma (A549), epidermoid carcinoma (A431), and breast cancer (MDA-MB 231). Both compounds exhibited moderate to high cytotoxic activity, with complex 1 showing a greater propensity to induce cell death, particularly in the A431 and MDA-MB 231 cell lines.

Generation of glucosylantimycins by heterologous expression of a promiscuous glycosyltransferase in a deepsea-derived Streptomyces.

Antimycins are a class of depsipeptide compounds that exhibit diverse bioactivities. However, their potential clinical applications are hampered by high cell toxicities. Glycosylation usually has profound impacts on the physicochemical properties, bioactivities and toxicities of natural products. In this study, we overexpressed an artificial glycosyltransferase (GT) gene sbmGT1 in deepsea-derived Streptomyces albus ZH66, leading to the discovery of three new antimycin derivatives glucosylantimycins A, B and C (1-3). Their structures were determined by a combination of spectroscopic methods, including high resolution electrospray ionisation mass spectrometry (HRESIMS) and nuclear magnetic resonance (NMR) analysis. The glycosylation remarkably improved the water solubility but simultaneously reduced the cytotoxicities of antimycins towards human cervix epidermoid carcinoma (HeLa) and human hepatic carcinoma (HepG2) cell lines.

The Dose Rate of Corpuscular Ionizing Radiation Strongly Influences the Severity of DNA Damage, Cell Cycle Progression and Cellular Senescence in Human Epidermoid Carcinoma Cells.

Modern radiotherapy utilizes a broad range of sources of ionizing radiation, both low-dose-rate (LDR) and high-dose-rate (HDR). However, the mechanisms underlying specific dose-rate effects remain unclear, especially for corpuscular radiation. To address this issue, we have irradiated human epidermoid carcinoma A431 cells under LDR and HDR regimes. Reducing the dose rate has lower lethality at equal doses with HDR irradiation. The half-lethal dose after HDR irradiation was three times less than after LDR irradiation. The study of mechanisms showed that under HDR irradiation, the radiation-induced halt of mitosis with the accompanying emergence of giant cells was recorded. No such changes were recorded after LDR irradiation. The level of DNA damage is significantly greater after HDR irradiation, which may be the main reason for the different mechanisms of action of HDR and LDR irradiations. Comparing the mechanisms of cell response to LDR and HDR irradiations may shed light on the mechanisms of tumor cell response to ionizing radiation and answer the question of whether different dose rates within the same dose range can cause different clinical effects.

Luteolin (LUT) Induces Apoptosis and Regulates Mitochondrial Membrane Potential to Inhibit Cell Growth in Human Cervical Epidermoid Carcinoma Cells (Ca Ski).

Background/Objectives: Luteolin (LUT) is a natural flavonoid with known anti-inflammatory, antioxidant, and anti-cancer properties. Cervical cancer, particularly prevalent in certain regions, remains a significant health challenge due to its high recurrence and poor response to treatment. This study aimed to investigate the anti-tumor effects of LUT on human cervical epidermoid carcinoma cells (Ca Ski), focusing on cell growth inhibition, apoptosis induction, and regulation of mitochondrial membrane potential. Methods: Ca Ski cells were treated with varying concentrations of LUT (0, 25, 50, 100 µM) for different time periods (24, 48, 72 hours). Cell viability was measured using the MTT assay, apoptosis was assessed by flow cytometry with annexin V-FITC/PI staining, and changes in mitochondrial membrane potential were evaluated using JC-1 staining. Caspase-3 activation was examined by flow cytometry, and expression of apoptosis-related proteins (caspase-3, -8, -9, AIF) was analyzed via Western blotting. Results: LUT significantly inhibited the growth of Ca Ski cells in a dose- and time-dependent manner, with the most pronounced effects observed at 100 µM over 72 hours. Flow cytometry confirmed that LUT induced apoptosis without causing necrosis. Mitochondrial membrane potential was reduced after LUT treatment, coinciding with increased caspase-3 activation. Western blot analysis revealed the upregulation of pro-apoptotic proteins caspase-3, -8, -9, and AIF, indicating that LUT induces apoptosis through the intrinsic mitochondrial pathway. Conclusions: Luteolin effectively inhibits cervical cancer cell proliferation and induces apoptosis by disrupting mitochondrial membrane potential and activating caspases. These findings suggest that LUT holds potential as a therapeutic agent for cervical cancer, with further studies needed to explore its in vivo efficacy and broader clinical applications.

One‐Step Synthesis of Novel Erlotinib Analogs Catalyzed by Nano‐CuO as Potent Anticancer Agent

ABSTRACTTwenty new substituted erlotinib analogs with anticancer activity were produced with good to excellent yields through the one‐step reaction of erlotinib, aromatic aldehydes, and cyclic secondary amines such as piperidine, morpholine, pyrrolidine, N‐methylpiperazine, or imidazole using nano‐CuO in choline chloride: urea (ChCl:urea) solvent under ultrasound irradiation at 80°C. MTT protocol was applied to investigate the cytotoxicity of all produced substituted erlotinib analogs in A431 (human epidermoid carcinoma cell) and HU02 (foreskin fibroblast) cell lines. The results illustrated that at a concentration of less than 10 μM, the growth of A431 cells could be inhibited by the produced compounds. Compared to erlotinib as positive control, the highest cytotoxic activity with IC50 equal to 2.58 ± 0.57 μM belonged to compound 4c carrying 4‐fluorobenzene with piperidine substitution. All of the synthesized compounds showed significant cytotoxic activity on A431, while showing no apparent cytotoxicity to HU02. The reasons for the stronger cytotoxic activity 4c can be most probably attributed to the two phenomena of greater solubility of the fluoro derivative and the flexibility of piperidine. Based on this study, compound 4c is the most promising compound with anticancer properties.

Novel alloxazine analogues: design, synthesis, and antitumour efficacy enhanced by kinase screening, molecular docking, and ADME studies

This study describes the development of novel alloxazine analogues as potent antitumor agents with enhanced selectivity for tumour cells. Twenty-nine out of 45 newly compounds were investigated in vitro for their growth inhibitory activities, against two human tumour cell lines, namely, the human T-cell acute lymphoblastoid leukaemia cell line (CCRF-HSB-2) and human oral epidermoid carcinoma cell line (KB), and the antitumor agent “Ara-C” was used as a positive reference in this investigation. Compounds 9e and 10J were the highest among their analogues, against both tumour cell lines (CCRF-HSB-2 and KB). Correlation analyses demonstrated a strong relationship between the IC50 values and AutoDock binding free energy or calculated inhibition (Ki ). The study delves into structure–activity relationships (SARs) through advanced modelling tools integrated with structure-based drug design (SBDD) using GOLD 5.2.2, AutoDock 4.2, and Accelrys Discovery Studio 3.5. Physicochemical properties, pharmacokinetics, drug-likeness, and toxicity predictions of the most potent alloxazine derivatives were conducted using ProTox-II and Swiss ADME for effective antitumor agents with improved selectivity.

Harnessing the power of Neobacillus niacini AUMC-B524 for silver oxide nanoparticle synthesis: optimization, characterization, and bioactivity exploration

BackgroundBiotechnology provides a cost-effective way to produce nanomaterials such as silver oxide nanoparticles (Ag2ONPs), which have emerged as versatile entities with diverse applications. This study investigated the ability of endophytic bacteria to biosynthesize Ag2ONPs.ResultsA novel endophytic bacterial strain, Neobacillus niacini AUMC-B524, was isolated from Lycium shawii Roem. & Schult leaves and used to synthesize Ag2ONPS extracellularly. Plackett–Burman design and response surface approach was carried out to optimize the biosynthesis of Ag2ONPs (Bio-Ag2ONPs). Comprehensive characterization techniques, including UV–vis spectral analysis, Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction, dynamic light scattering analysis, Raman microscopy, and energy dispersive X-ray analysis, confirmed the precise composition of the Ag2ONPS. Bio-Ag2ONPs were effective against multidrug-resistant wound pathogens, with minimum inhibitory concentrations (1–25 µg mL−1). Notably, Bio-Ag2ONPs demonstrated no cytotoxic effects on human skin fibroblasts (HSF) in vitro, while effectively suppressing the proliferation of human epidermoid skin carcinoma (A-431) cells, inducing apoptosis and modulating the key apoptotic genes including Bcl-2 associated X protein (Bax), B-cell lymphoma 2 (Bcl-2), Caspase-3 (Cas-3), and guardian of the genome (P53).ConclusionsThese findings highlight the therapeutic potential of Bio-Ag2ONPs synthesized by endophytic N. niacini AUMC-B524, underscoring their antibacterial efficacy, anticancer activity, and biocompatibility, paving the way for novel therapeutic strategies.

Lawsone attenuates acute low dose ethanol-induced skin inflammation in A431 epidermoid carcinoma skin cells and its possible mechanisms in targeting interleukin (IL)-1α in silico

Standard treatment for acute skin inflammatory conditions comes with unwanted side effects. Traditionally, Lawsonia inermis has been used to treat skin-related ailments, with lawsone as the main active phytochemical is predicted to inhibit a skin pro inflammatory cytokine, IL-1α. This study is aimed to evaluate the anti- inflammatory effect of lawsone in acute ethanol-induced skin inflammatory condition in vitro, by targeting IL-1α in silico. Basically, the IC50 of lawsone on human epidermoid carcinoma cell line (A431) was obtained by using MTT proliferation assay, followed by acute low dose ethanol-induced inflammatory skin condition on A431 cells to determine cell viability. Next, molecular docking study was done by utilizing Autodock Vina software, and further analyzed by ProteinsPlus and PyMol softwares. Meaningful interaction that exist in the binding of lawsone to IL-1α was determined by molecular docking results comparison with two other compounds (kirenol and curcumin diglucoside). In vitro study showed the IC50 of lawsone in low cytotoxicity level at 150 µM. Skin anti-inflammatory assay indicated that lawsone has highly significant (p<0.05) anti-inflammatory activity at 9.375 µM at low concentration, but not effective at higher concentrations (more than 18.75 µM). In silico studies indicated binding of lawsone to IL-1α with top binding affinity of -5.2 kcal/mol, at binding residues of Asp65 and Ile68. Docking comparison analysis to determine meaningful interaction comparison indicated three key IL-1α binding residues common to most tested compounds, such as Ile68 and Asp65 thus supported the predicted mechanistic pathway. This highlighted lawsone potential as a future skin anti-inflammatory agent with minimal toxicity.

In Vitro Superparamagnetic Hyperthermia Employing Magnetite Gamma-Cyclodextrin Nanobioconjugates for Human Squamous Skin Carcinoma Therapy.

In vitro alternative therapy of human epidermoid squamous carcinoma (A431) by superparamagnetic hyperthermia (SPMHT) using Fe3O4 (magnetite) superparamagnetic nanoparticles (SPIONs) with an average diameter of 15.8 nm, bioconjugated with hydroxypropyl gamma-cyclodextrins (HP-γ-CDs) by means of polyacrylic acid (PAA) biopolymer, is presented in this paper. The therapy was carried out at a temperature of 43 °C for 30 min using the concentrations of Fe3O4 ferrimagnetic nanoparticles from nanobioconjugates of 1, 5, and 10 mg/mL nanoparticles in cell suspension, which were previously found by us to be non-toxic for healthy cells (cell viabilities close to 100%), according to ISO standards (cell viability must be greater than 70%). The temperature for the in vitro therapy was obtained by the safe application (without exceeding the biological limit and cellular damage) of an alternating magnetic field with a frequency of 312.4 kHz and amplitudes of 168, 208, and 370 G, depending on the concentration of the magnetic nanoparticles. The optimal concentration of magnetic nanoparticles in suspension was found experimentally. The results obtained after the treatment show its high effectiveness in destroying the A431 tumor cells, up to 83%, with the possibility of increasing even more, which demonstrates the viability of the SPMHT method with Fe3O4-PAA-(HP-γ-CDs) nanobioconjugates for human squamous cancer therapy.

The Agonistic Activity of the Human Epidermal Growth Factor is Reduced by the D46G Substitution.

Resistance to anti-tumor agents targeting the epidermal growth factor receptor (EGFR) reduces treatment response and requires the development of novel EGFR antagonists. Mutant epidermal growth factor (EGF) forms with reduced agonistic activity could be promising agents in cancer treatment. EGF D46G affinity to EGFR domain III was assessed with affinity chromatography. EGF D46G acute toxicity in Af albino mice at 320 and 3200 μg/kg subcutaneous doses was evaluated. EGF D46G activity in human epidermoid carcinoma cells at 10 ng/mL concentration in serum-free medium and in subcutaneous Ehrlich ascites carcinoma mice model at 320 μg/kg dose was studied. The D46G substitution decreases the thermal stability of EGF complexes with EGFR domain III by decreasing the ability of the C-terminus to be released from the intermolecular β- sheet. However, with remaining binding sites for EGFR domain I, EGF D46G effectively competes with other EGF-like growth factors for binding to EGFR and does not demonstrate toxic effects in mice. EGF D46G inhibits the proliferation of human epidermoid carcinoma cells compared to native EGF. A single subcutaneous administration of EGF D46G along with Ehrlich carcinoma cells injection inhibits the proliferation of these cells and delays tumor formation for up to seven days. EGF D46G can be defined as a partial EGFR agonist as this mutant form demonstrates reduced agonistic activity compared to native EGF. The study emphasizes the role of the EGF C-terminus in establishing interactions with EGFR domain III, which are necessary for EGFR activation and subsequent proliferation of cells.

Evaluation of antiproliferative activity of Naringin in Human epidermoid carcinoma cell line (A431)

Evaluation of antiproliferative activity of Naringin in Human epidermoid carcinoma cell line (A431)

Cytotoxic Effects of Doxorubicin on Cancer Cells and Macrophages Depend Differently on the Microcarrier Structure.

Microparticles are versatile carriers for controlled drug delivery in personalized, targeted therapy of various diseases, including cancer. The tumor microenvironment contains different infiltrating cells, including immune cells, which can affect the efficacy of antitumor drugs. Here, prototype microparticle-based systems for the delivery of the antitumor drug doxorubicin (DOX) were developed, and their cytotoxic effects on human epidermoid carcinoma cells and macrophages derived from human leukemia monocytic cells were compared in vitro. DOX-containing calcium carbonate microparticles with or without a protective polyelectrolyte shell and polyelectrolyte microcapsules of about 2.4-2.5 μm in size were obtained through coprecipitation and spontaneous loading. All the microstructures exhibited a prolonged release of DOX. An estimation of the cytotoxicity of the DOX-containing microstructures showed that the encapsulation of DOX decreased its toxicity to macrophages and delayed the cytotoxic effect against tumor cells. The DOX-containing calcium carbonate microparticles with a protective polyelectrolyte shell were more toxic to the cancer cells than DOX-containing polyelectrolyte microcapsules, whereas, for the macrophages, the microcapsules were most toxic. It is concluded that DOX-containing core/shell microparticles with an eight-layer polyelectrolyte shell are optimal drug microcarriers due to their low toxicity to immune cells, even upon prolonged incubation, and strong delayed cytotoxicity against tumor cells.

TMEM205 induces TAM/M2 polarization to promote cisplatin resistance in gastric cancer

Cisplatin (DDP) is a basic chemotherapy drug for gastric cancer (GC). With the increase of DDP drug concentration in clinical treatment, cancer cells gradually became resistant. Therefore, it is necessary to find effective therapeutic targets to enhance the sensitivity of GC to DDP. Studies have shown that Transmembrane protein 205 (TMEM205) is overexpressed in DDP-resistant human epidermoid carcinoma cells and correlates with drug resistance, and database analyses show that TMEM 205 is also overexpressed in GC, but its role in cisplatin-resistant gastric cancer remains unclear. In this study, we chose a variety of experiments in vivo and vitro, aiming to investigate the role of TMEM 205 in cisplatin resistance in gastric cancer. The results showed that TMEM 205 promoted proliferation, stemness, epithelial–mesenchymal transition (EMT), migration and angiogenesis of gastric cancer cells through activation of the Wnt/β-catenin signaling pathway. In addition, TMEM205 promotes GC progression by inducing M2 polarization of tumor-associated macrophages (TAMs). These results suggest that TMEM205 may be an effective target to regulate the sensitivity of GC to DDP, providing a new therapeutic direction for clinical treatment.

Berberine encapsulated phenylboronic acid-conjugated pullulan nanoparticles: Synthesis, characterization and anticancer activity validated in A431 skin cancer cells and 3D spheroids

Polysaccharide-based drug delivery systems are in high demand due to their biocompatibility, non-toxicity, and low-cost. In this study, sialic acid receptor targeted 4-carboxy phenylboronic acid modified pullulan-stearic acid conjugate (4-cPBA-PUL-SA) was synthesized and characterized for the delivery of Berberine (BBR). BBR-loaded 4-cPBA-PUL-SA nanoparticles (BPPNPs) were monodispersed (PDI: 0.238 ± 0.07), with an average hydrodynamic particle size of 191.6 nm and 73.6 % encapsulation efficiency. BPPNPs showed controlled BBR release and excellent colloidal stability, indicating their potential for drug delivery application. The cytotoxicity results indicated that BPPNPs exhibited dose and time-dependent cytotoxicity against human epidermoid carcinoma cells (A431) as well as 3D spheroids. Targeted BPPNPs demonstrated significantly higher anticancer activity compared to BBR and non-targeted BPNPs. The IC50 values for BPPNPs (2.29 μg/ml) were significantly lower than BPNPs (4.13 μg/ml) and BBR (19.61 μg/ml), indicating its potential for skin cancer treatment. Furthermore, CSLM images of A431 cells and 3D spheroids demonstrated that BPPNPs have higher cellular uptake and induced apoptosis compared to free BBR and BPNPs. In conclusion, BPPNPs demonstrate promising potential as an effective drug delivery system for skin cancer therapy.

Statistical modeling, optimization and characterization of andrographolide loaded emulgel for its therapeutic application on skin cancer through enhancing its skin permeability

Andrographolide is a natural diterpene lactone with multiple biological effects. In the present study, a total of 11 andrographolide-loaded emulgels (ANG 1- ANG 11) were prepared by emulsification and solvent evaporation method using flaxseed oil and xanthan gum in different ratios, as suggested by the Design-Expert software. A 2-factor-5-level design was employed with different responses including spreadability, extrudability, viscosity, and drug release after 1 h (h) and 24 h. Based on the Design-Expert software response, the optimized emulgel ANG 12 was formulated and evaluated. The 24 h In-vitro drug release was found to be 95.7 % following Higuchi kinetics. Ex-vivo skin retention of 784.78 ug/cm2 was observed during the study. MTT assay performed on Human epidermoid carcinoma (A-431) cells demonstrated cell growth arrest at G0/G1 and G2/M phase after 24 h of ANG 12 treatment (IC50: 11.5 µg/ml). The cellular permeability of ANG-12 was assessed by Fluorescein isothiocyanate (FITC) assay. Compared to untreated cells (0.54 % uptake) the ANG-12 treated cells had shown 87.17 % FITC permeation. The biocompatibility study performed on non-cancerous human dermal fibroblast cells (HDF cells) shows 91.54 % viability after 24 h of the treatment showing the non-toxic nature of ANG-12. Confocal imaging had shown a significant time-dependent increase in in-vivo cellular uptake with enhanced, progressive penetration of the emulgel into the skin. An in-vivo skin irritation study conducted on Swiss albino mice confirmed the safety aspects of the ANG 12. Hence, it can be concluded that nanoemulgel of andrographolide (ANG 12) could be a novel approach to treating skin cancer.

ATP2B4 is an essential gene for epidermal growth factor-induced macropinocytosis in A431 cells.

Macropinocytosis (MPC) is a large-scale endocytosis pathway that involves actin-dependent membrane ruffle formation and subsequent ruffle closure to generate macropinosomes for the uptake of fluid-phase cargos. MPC is categorized into two types: constitutive and stimuli-induced. Constitutive MPC in macrophages relies on extracellular Ca2+ sensing by a calcium-sensing receptor. However, the link between stimuli-induced MPC and Ca2+ remains unclear. Here, we find that both intracellular and extracellular Ca2+ are required for epidermal growth factor (EGF)-induced MPC in A431 human epidermoid carcinoma cells. Through investigation of mammalian homologs of coelomocyte uptake defective (CUP) genes, we identify ATP2B4, encoding for a Ca2+ pump called the plasma membrane calcium ATPase 4 (PMCA4), as a Ca2+-related regulator of EGF-induced MPC. Knockout (KO) of ATP2B4, as well as depletion of extracellular/intracellular Ca2+, inhibited ruffle closure and macropinosome formation, without affecting ruffle formation. We demonstrate the importance of PMCA4 activity itself, independent of interactions with other proteins via its C-terminus known as a PDZ domain-binding motif. Additionally, we show that ATP2B4-KO reduces EGF-stimulated Ca2+ oscillation during MPC. Our findings suggest that EGF-induced MPC requires ATP2B4-dependent Ca2+ dynamics.

A Novel In Vitro Pathological Model for Studying Neural Invasion in Non-Melanoma Skin Cancer.

Neural Invasion (NI) is a key pathological feature of cancer in the colonization of distant tissues, and its underlying biological mechanisms are still scarcely known. The complex interactions between nerve and tumor cells, along with the stroma, make it difficult to reproduce this pathology in effective study models, which in turn has limited the understanding of NI pathogenesis. In this study, we have designed a three-dimensional model of NI squamous cell carcinoma combining human epidermoid carcinoma cells (hECCs) with a complete peripheral nerve segment encapsulated in a fibrine-agarose hydrogel. We recreated two vital processes of NI: a pre-invasive NI model in which hECCs were seeded on the top of the nerve-enriched stroma, and an invasive NI model in which cancer cells were immersed with the nerve in the hydrogel. Histological, histochemical and immunohistochemical analyses were performed to validate the model. Results showed that the integration of fibrin-agarose advanced hydrogel with a complete nerve structure and hECCs successfully generated an environment in which tumor cells and nerve components coexisted. Moreover, this model correctly preserved components of the neural extracellular matrix as well as allowing the proliferation and migration of cells embedded in hydrogel. All these results suggest the suitability of the model for the study of the mechanisms underlaying NI.

Negative regulation of thyroid adenoma-associated protein (THADA) in the cardiac glycoside-induced anti-cancer effect

Cardiac glycosides, known as inhibitors of Na+,K+-ATPase, have anti-cancer effects such as suppression of cancer cell proliferation and induction of cancer cell death. Here, we examined the signaling pathway elicited by cardiac glycosides in the human hepatocellular carcinoma HepG2 cells and human epidermoid carcinoma KB cells. Three kinds of cardiac glycosides (ouabain, oleandrin, and digoxin) inhibited the cancer cell proliferation and decreased the expression level of thyroid adenoma-associated protein (THADA). Interestingly, the knockdown of THADA inhibited cancer cell proliferation, and the proliferation was significantly rescued by re-expression of THADA in the THADA-knockdown cells. In addition, the THADA-knockdown markedly decreased the expression level of L-type amino acid transporter LAT1. Cardiac glycosides also reduced the LAT1 expression. The LAT1 inhibitor, JPH203, significantly weakened the cancer cell proliferation. These results suggest that the binding of cardiac glycosides to Na+,K+-ATPase negatively regulates the THADA-LAT1 pathway, exerting the anti-proliferative effect in cancer cells.