KLK6 protease accelerates skin tumor formation and progression.

Kallikrein-related peptidase 6 (KLK6) is a serine protease that is aberrantly altered in various types of cancer, but its role in non-melanoma skin cancer has not been investigated. KLK6 is active in epidermis and has been linked to normal skin differentiation. Thus, we investigated whether it could be implicated in skin tumorigenesis in vivo. Carcinogenesis was induced in Klk6-/- mice by epidermal application of 7,12-dimethylbenz[a]anthracene/12-O-tetradecanoylphorbol 13-acetate (DMBA/TPA), and multistage skin tumor development and progression was monitored closely until squamous cell carcinomas (SCCs) and invasive tumors formed. Klk6-/- (but also Klk6+/-) mice were highly resistant to tumor growth/development manifested by their highly diminished numbers and delayed onset of tumors compared with wild-type (wt) mice. Histological analyses of the few tumors that developed in Klk6-/- after prolonged (>1 year) chemical challenge revealed that these were mainly benign papillomas, whereas in wt mice tumors progressed to SCCs. Inflammation was attenuated in Klk6-/- skin following chronic exposure to TPA, indicated by markedly low expression of proinflammatory cytokines, in direct contrast to wt. Further, in Klk6-/- mice, the ability of implanted nascent PDVC57 skin cancer cells to form tumors was highly diminished. Our study identified KLK6 as a new tumor-promoting factor of early skin cancer and suggested that KLK6 is an important molecular link in the development of skin inflammation and in tumor-promoting inflammatory processes.

Roles of DNA repair enzyme OGG1 in innate immunity and its significance for lung cancer.

Cytokines are pivotal mediators of the immune response, and their coordinated expression protects host tissue from excessive damage and oxidant stress. Nevertheless, the development of lung pathology, including asthma, chronic obstructive pulmonary disease, and ozone-induced lung injury, is associated with oxidant stress; as evidence, there is a significant increase in levels of the modified guanine base 7,8-dihydro-8-oxoguanine (8-oxoG) in the genome. 8-OxoG is primarily recognized by 8-oxoguanine glycosylase 1 (OGG1), which catalyzes the first step in the DNA base excision repair pathway. However, oxidant stress in the cell transiently halts enzymatic activity of substrate-bound OGG1. The stalled OGG1 facilitates DNA binding of transactivators, including NF-κB, to their cognate sites to enable expression of cytokines and chemokines, with ensuing recruitments of inflammatory cells. Hence, defective OGG1 will modulate the coordination between innate and adaptive immunity through excessive oxidant stress and cytokine dysregulation. Both oxidant stress and cytokine dysregulation constitute key elements of oncogenesis by KRAS, which is mechanistically coupled to OGG1. Thus, analysis of the mechanism by which OGG1 modulates gene expression helps discern between beneficial and detrimental effects of oxidant stress, exposes a missing functional link as a marker, and yields a novel target for lung cancer.

Canagliflozin-loaded magnetic nanoparticles as potential treatment of hypoxic tumors in combination with radiotherapy.

AIM: To synthesize magnetic nanoparticles loaded with the SGLT2-inhibitor canagliflozin (CANA) and evaluate its anticancer potential under normoxic and hypoxic conditions in combination or not with radiotherapy. MATERIAL & METHODS: Iron oxide nanoparticles were synthesized via an alkaline hydrolytic precipitation of iron precursor in the presence of poly(methacrylic acid)-graft-poly(ethyleneglycol methacrylate). CANA was conjugated to the nanoparticles using N-ethyl-N'-(3-dimethyl aminopropyl) carbodiimide (EDC)/N-hydroxysuccinimide chemistry. The anticancer efficacy of the nanoparticles was evaluated in cancer cell lines and in a mouse PDV C57 tumor model. RESULTS: In the mouse xenograft cancer model, the combination of CANA-loaded nanoparticles with radiotherapy (in the presence of an external magnetic field at the tumor site) exhibited higher antitumor activity compared with the combination of free CANA with radiotherapy. CONCLUSION: The results obtained indicate the potential that the combination of selective delivery of a SGLT2 inhibitor such as CANA with radiotherapy holds as an anticancer treatment.

A Triphenylphosphonium-Functionalized Mitochondriotropic Nanocarrier for Efficient Co-Delivery of Doxorubicin and Chloroquine and Enhanced Antineoplastic Activity.

Drug delivery systems that target subcellular organelles and, in particular, mitochondria are considered to have great potential in treating disorders that are associated with mitochondrial dysfunction, including cancer or neurodegenerative diseases. To this end, a novel hyperbranched mitochondriotropic nanocarrier was developed for the efficient co-delivery of two different (both in chemical and pharmacological terms) bioactive compounds. The carrier is based on hyperbranched poly(ethyleneimine) functionalized with triphenylphosphonium groups that forms ~100 nm diameter nanoparticles in aqueous media and can encapsulate doxorubicin (DOX), a well-known anti-cancer drug, and chloroquine (CQ), a known chemosensitizer with arising potential in anticancer medication. The anticancer activity of this system against two aggressive DOX-resistant human prostate adenocarcinoma cell lines and in in vivo animal studies was assessed. The co-administration of encapsulated DOX and CQ leads to improved cell proliferation inhibition at extremely low DOX concentrations (0.25 µΜ). In vivo experiments against DU145 human prostate cancer cells grafted on immunodeficient mice resulted in tumor growth arrest during the three-week administration period and no pervasive side effects. The findings put forward the potential of such targeted low dose combination treatments as a therapeutic scheme with minimal adverse effects.

The molecular basis of fertilization (Review).

Fertilization is the fusion of the male and female gamete. The process involves the fusion of an oocyte with a sperm, creating a single diploid cell, the zygote, from which a new individual organism will develop. The elucidation of the molecular mechanisms of fertilization has fascinated researchers for many years. In this review, we focus on this intriguing process at the molecular level. Several molecules have been identified to play a key role in each step of this intriguing process (the sperm attraction from the oocyte, the sperm maturation, the sperm and oocyte fusion and the two gamete pronuclei fusion leading to the zygote). Understanding the molecular mechanisms of the cell­cell interactions will provide a better understanding of the causes of fertility issues due to fertilization defects.

N-bromotaurine surrogates for loss of antiproliferative response and enhances cisplatin efficacy in cancer cells with impaired glucocorticoid receptor.

Glucocorticoids (GCs) are frequently used in anticancer combination regimens; however, their continuous use adds selective pressure on cancer cells to develop GC-resistance via impairment of the glucocorticoid receptor (GR), therefore creating a need for GC-alternatives. Based on the drug repurposing approach and the commonalities between inflammation and neoplasia, drugs that are either in late-stage clinical trials and/or already marketed for GC-refractory inflammatory diseases could be evaluated as GC-substitutes in the context of cancer. Advantageously, unlike new molecular entities currently being de novo developed to restore GC-responsiveness of cancer cells, such drugs have documented safety and efficacy profile, which overall simplifies their introduction in clinical cancer trials. In this study, we estimated the potential of a well-established, multistage, cell line-based, mouse skin carcinogenesis model to be exploited as an initial screening tool for unveiling covert GC-substitutes. First, we categorized the cell lines of this model to GC-sensitive and GC-resistant, in correlation with their corresponding GR status, localization, and functionality. We found that GC-resistance starts in papilloma stages, due to a dysfunctional GR, which is overexpressed, DNA binding-competent, but transactivation-incompetent in papilloma, squamous, and spindle stages of the model. Then, aided by this tool, we evaluated the ability of N-bromotaurine, a naturally occurring, small-molecule, nonsteroid anti-inflammatory drug which is under consideration for use interchangeably/in replacement to GCs in skin inflammations, to restore antiproliferative response of GC-resistant cancer cells. Unlike GCs, N-bromotaurine inhibited cell-cycle progression in GC-resistant cancer cells and efficiently synergized with cisplatin, thus indicating a potential to be exploited instead of GCs against cancer.