Anticancer genes (NOXA, PAR-4, TRAIL) are de-regulated in breast cancer patients and can be targeted by using a ribosomal inactivating plant protein (riproximin).

BACKGROUND: Anticancer genes are an endogenous defense against transformed cells as they impose antineoplastic effects upon ectopic expression. Profiling the expression of these genes is fundamental for exploring their prognostic and therapeutic relevance in cancers. Natural compounds can upregulate anticancer genes in malignant cells and thus be useful for therapeutic purposes. In this study, we identified the expression levels of anticancer genes in breast cancer clinical isolates. In addition, the purified and sequenced plant protein (riproximin) was evaluated for its potential to induce anticancer genes in two breast cancer cell lines. METHODOLOGY: Expression profiles of three anticancer genes (NOXA, PAR-4, TRAIL) were identified by immunohistochemistry in 45 breast cancer clinical isolates. Breast cancer cells were exposed to riproximin and expression of the anticancer genes was determined by microarray, real-time PCR and western blot methodologies. Lastly, a bioinformatic approach was adopted to highlight the molecular/functional significance of the anticancer genes. RESULTS: NOXA expression was evenly de-regulated among the clinical isolates, while PAR-4 was significantly down-regulated in majority of the breast cancer tissues. In contrast, TRAIL expression was increased in most of the clinical samples. Expression levels of the anticancer genes followed a distinct trend in accordance with the disease severity. Riproximin showed a substantial potential of inducing expression of the anticancer genes in breast cancer cells at transcriptomic and protein levels. The bioinformatic approach revealed involvement of anticancer genes in multiple cellular functions and signaling cascades. CONCLUSION: Anticancer genes were de-regulated and showed discrete expression patterns in breast cancer patient samples. Riproximin effectively induced the expression of selected anticancer genes in breast cancer cells.

Expression and immobilization of trypsin-like domain of serine protease from Pseudomonas aeruginosa for improved stability and catalytic activity.

Protein engineering and enzyme immobilization strategies have produced numerous biocatalysts for modern industrial applications. In this study, we have also used these two strategies for improving the operational stability and catalytic efficiency of serine protease from Pseudomonas aeruginosa. The enzyme serine protease was truncated to separate its trypsin-like domain from the PDZ1 and PDZ2 domains. The truncated trypsin-like domain was expressed in Escherichia coli BL21, and its catalytic activity and thermostability were estimated. Later this trypsin-like domain was immobilized with 2% Na-alginate. The immobilized domain showed 10°C increase in optimum temperature compared to its free counterpart. Kinetic studies showed two-folds increased Vmax of the immobilized domain. Likewise, the Km value of this domain was 11.5 folds lower compared to the free trypsin-like domain. The catalytic efficiency (Kcat /Km ) of the immobilized enzyme also elevated to 311 folds. Additionally, the immobilized trypsin-like domain remained active in the presence of surfactants (Triton-X 100, SDS, and Tween-40) and metal ions (Mg2+ , Ca2+ , Na+ , and Zn2+ ). It also efficiently removes gelatin layer from X-ray film and hair from sheepskin. Thus, the immobilized trypsin-like domain of serine protease, with increased thermostability and catalytic efficiency, is operationally more stable than the soluble truncated trypsin-like domain.