A simple method for spontaneous transfection into mammalian cells (both adherent and suspension in culture) with plasmid DNA is described. This method does not require any specific DNA carrier or technical device and can be applied for obtaining both transient and stably transfected cells. The efficiency of spontaneous transfection is slightly lower in comparison with that of the conventional calcium phosphate and lipofectin transfection methods and does not depend on the type of cell culture used.
Abstract Skin cancer is the most common class of malignancies in humans with increasing incidence worldwide. Although surgery remains the most common treatment approach, relapses after surgery necessitate other treatment options. There is an increasing clinical demand for topical treatments for skin cancer that can improve the drug's cutaneous localization while limiting systemic absorption. In this study, hyaluronic acid (HA) conjugates are successfully synthesized by attaching a third‐generation retinoid (bexarotene) and a histone deacetylase inhibitor (vorinostat) to HA via ester bonds. The conjugates are characterized to ensure identity and quantify total drug loading. HA‐BEX and HA‐VOR exhibit a synergistic anticancer effect against human squamous cell carcinoma (A431) and human cutaneous T cell lymphoma cell lines (HUT 78) at specific ratios with minimal adverse effect on primary human keratinocytes and fibroblasts. Confocal microscopy demonstrates localization of the conjugates inside the cancer cells. Ex vivo skin permeation studies on human skin explants confirm their ability to penetrate the stratum corneum and reach the deep dermis. Biodistribution studies in the skin reveal the presence of both drugs in the epidermis and dermis in amounts sufficient to exert inhibitory effect on cancer cells. HA‐bexarotene‐vorinostat conjugates offer an excellent therapeutic option to treat skin cancers.
The aim of this study was to examine the effect of interferons (IFNs) on the recovery of UV-damaged cells by means of measuring cell viability rates. The influence of the recombinant human interferons IFN-α, IFN-βand IFN-γ on the repair capacity of the UV-irradiated human cell lines WISH and HeLa was studied. The ability of cells to repair UV-induced damage was determined by the comet assay and both short- and long-term survival assays in proliferating cell cultures. We found that INFs negatively regulated DNA repair in cells damaged by UV light. One day after treatment, in both cell lines tested, IFN-α had a stronger inhibitory effect than IFN-γ. Combined treatment with different IFNs exhibited a stronger inhibitory effect on cell recovery than treatment with each of them. The protein kinase inhibitor wortmanin further aggravated the effect of IFNs on cell survival.
Abstract Y-box binding protein 1 (YB-1), which is encoded by YBX1 gene, is a multifunctional cold-shock protein that binds both DNA and RNA to orchestrate transcription as well as RNA processing and translation. Recently, we demonstrated that YBX1 is a post-transcriptional effector required for the maintenance of epidermal homeostasis. Although it was well known that YBX1 plays prominent pro-oncogenic roles in malignant transformation and cell invasion in a wide variety of cancers, the role of YBX1 in cutaneous squamous cell carcinoma (cSCC) is poorly understood. Here, we report that YBX1 protein level is higher in cSCC tumor compared with non-neoplastic skin, but it goes down in metastatic states. According to this finding, YBX1-KD cSCC primary cell lines show an increase of cell migration and invasion in vitro assay and in a context that mimics the natural three-dimensional environment of tumor with organotypic skin equivalent cultures. Furthermore, we found that YBX1-KD promotes an epithelial-to-mesenchymal transition and leads to the detection of more metastases in vivo after tail vein injection of YBX1-KD cSCC cells when compared with the injection of control cells. YBX1 is predominantly found in the cytoplasm of SCC cells. Therefore, we focused on the role of YBX1 as a post-transcriptional regulatorand performed an eCLIP-seq (crosslinking immunoprecipitation sequencing) to identify its direct RNA targets. We found that YBX1 binds novel pro-invasive RNA regulons associated to cell-cell and cell-matrix adhesions. Through the interpolation of the analysis of RNA-seq and SILAC, we found that YBX1 KD up-modulates at post-transcriptional level several targets, involved into invasion and metastasis. Our study reveals that, in human cutaneous squamous cell carcinoma, loss of function of YBX1 promotes migration, invasiveness and metastasis, through the induction of an epithelial-to-mesenchymal transition regulated at post-transcriptional level. Citation Format: Stefano Sol, Fabiana Boncimino, Kristina Todorova, Anna Mandinova. YBX1 is a negative regulator of post-transcriptional program associated to EMT, invasion and metastasis in cSCC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB209.
Skin cancer encompasses a range of cutaneous malignancies, with non-melanoma skin cancers (NMSCs) being the most common neoplasm worldwide. Skin exposure is the leading risk factor for initiating NMSC. Ultraviolet (UV) light induces various genomic aberrations in both tumor-promoting and tumor-suppressing genes in epidermal cells. In conjunction with interactions with a changed stromal microenvironment and local immune suppression, these aberrations contribute to the occurrence and expansion of cancerous lesions. Surgical excision is still the most common treatment for these lesions; however, locally advanced or metastatic disease significantly increases the chances of morbidity or death. In recent years, numerous pharmacological targets were found through extensive research on the pathogenic mechanisms of NMSCs, leading to the development of novel treatments including Hedgehog pathway inhibitors for advanced and metastatic basal cell carcinoma (BCC) and PD-1/PD-L1 inhibitors for locally advanced cutaneous squamous cell carcinoma (cSCC) and Merkel cell carcinoma (MCC). Despite the efficacy of these new drugs, drug resistance and tolerability issues often arise with long-term treatment. Ongoing studies aim to identify alternative strategies with reduced adverse effects and increased tolerability. This review summarizes the current and emerging therapies used to treat NMSC.
Unfolding/folding transitions of recombinant human interferon-gamma (hIFNγ) in urea and guanidine chloride (Gn.HCl) solutions were studied by fluorescence spectroscopy. At pH 7.4 Gn.HCl was a much more efficient denaturant (midpoint of unfolding C* = 1.1 m and ΔG 0 = 13.4 kJ/mol) than urea (C* = 2.8 m and ΔG 0 = 11.7 kJ/mol). The close ΔG 0 values indicate that the contribution of electrostatic interactions to the stability of hIFNγ is insignificant. Both the pH dependence of the fluorescence intensity and the unfolding experiments in urea at variable pH showed that hIFNγ remains native in the pH range of 4.8-9.5. Using two quenchers, iodide and acrylamide, and applying the Stern-Volmer equation, a cluster of acidic groups situated in close proximity to the single tryptophan residue was identified. Based on the denaturation experiments at different pH values and on our earlier calculations of the electrostatic interactions in hIFNγ, we assume that the protonation of Asp63 causes conformational changes having a substantial impact on the stability of hIFNγ.
