ecdysone/neoplasms

Neoplastic lesions were induced in 10 out of 58 experimental toads (Bufo regularis) force-fed with alpha-ecdysone, which naturally occurs in the leaves of bracken fern (Pteris aquilina). The results of this study prove that alpha-ecdysone may be one of the factors responsible for the carcinogenicity

Alpha ecdysone is naturally present in the leaves of some plants, including the carcinogenic plant bracken fern (Pteris aquilina). Feeding mice with alpha-ecdysone at a dose level of 3 ppm/25 g body weight, 2 times per week for 22 months induced a significant increase in the body weight of the

Paradoxically, both hyaluronan (HA) and hyaluronidase are involved in malignant transformation and cancer progression. Their mechanisms of action, given the apparent disparities, are not understood. In many malignancies, levels of HA correlate with metastatic behavior while hyaluronidases suppress

Many human tumors express inducible NO synthetase (NOS2), but the roles of NO in tumor development are not fully elucidated. An important step during tumor development is the acquisition of apoptosis resistance. We investigated the dose-dependent effects of endogenously produced NO on apoptosis

Iron is involved in essential biochemical reactions ranging from respiration to DNA synthesis. Consequently, iron deprivation has been proposed as a strategy for inhibition of tumor cell growth. We recently described a novel iron chelator, tachypyridine

The p53-null human lung cancer cell line H1299 was used in order to generate clones with ecdysone-inducible p53 as well as ecdysone-inducible p21waf1. Induced expression of p53 resulted in irreversible cell growth arrest with characteristics of replicative senescence, suggesting that p53 can prevent

Macrophages can kill tumor cells by releasing high levels of nitric oxide (NO) and related reactive nitrogen species such as nitroxyl and peroxynitrite, after up-regulation of expression of the inducible nitric oxide synthase gene (iNOS). In this paper we describe two novel human cell lines that are

The search for new biologically active compounds is a topic of current research because of their ubiquitous availability and low toxicity. Plants of the Silene genus contain secondary metabolites known as phytoecdysteroids that reportedly have various biological activities. α-Ecdysone is a

Developmental studies revealed fundamental principles on how organ size and function is achieved, but less is known about organ adaptation to new physiological demands. In fruit flies, juvenile hormone (JH) induces intestinal stem cell (ISC) driven absorptive epithelial expansion balancing energy

Inactivation of the retinoblastoma (Rb) protein caused by gene mutation, association with oncoproteins from small DNA viruses, mutational inactivation of p16(Ink4a), or overexpression of cyclin D is a common feature of many human cancer cells and is causally associated with the aberrant

Increased levels of the protein kinase C (PKC) isoenzymes alpha and theta occur in conjunction with MDR1 gene expression in cells and tissues that have acquired a multidrug resistance (MDR) phenotype. Studies using PKC activators or antisense strategies against PKC suggest that activation of PKC

Ectopic protein expression in mammalian cells is a valuable tool to analyze protein functions. Increasingly, inducible promoters are being used for regulated gene expression. Here, we compare expression maxima, induction rates, and "leakiness" of the following promoter systems: (I) two

Walleye dermal sarcoma virus (WDSV) is a retrovirus aetiologically associated with a multifocal skin tumour of walleye. Tumours synchronously develop on 27% of fish and regress seasonally; their severity is influenced by water temperature. To functionally characterize the LTR of WDSV, the LTR was

In decapod crustaceans, molt hormone (ecdysone) production by Y-organs is suppressed by an eyestalk neurosecretory product, molt-inhibiting hormone (MIH). Environmental stressors are known to delay or prevent molting in crabs. The present study assesses the function of the MIH-Y-organ neuroendocrine

Minocycline is a broad spectrum, semi-synthetic tetracycline analog that is used to treat bacterial infection. Recently, this drug has been receiving increasing attention for its non-antibiotic properties, including anti-inflammatory, tumor suppressive, and neuroprotective effects. Drosophila is a