Bioprocessing Using Novel Cell Culture Systems

Plant regeneration from cell suspension culture in Saccharum officinarum L. and ascertaining of genetic fidelity through RAPD and ISSR markers

The aim of this study was to produce sugarcane plantlets from cell suspension culture and study its genetic fidelity using molecular markers. The study was carried out using sugarcane varieties Co 86032 and Q117. Callus cultures of both the varieties were optimized using six different callus induction media. After screening the growth response of callus on six different callus induction media, it was observed that medium no. VI supplemented with 500 mg l⁻¹ of each PVP, Casein hydrolysate and MES buffer showed high amounts of callus in Co 86032 (79.66 ± 0.44%) and Q117 (82.83 ± 1.69%). Addition of PEG 8000 at 2.5% to this medium had a profound impact on inducing somatic embryogenesis in Co 86032 (54.66 ± 1.76%) and Q117 (66.66 ± 2.60%) as compare to control (24.33 ± 1.76%) and (27.33 ± 2.73%), respectively. Cell suspension cultures were established by culturing embryogenic calli in liquid medium showed well established suspension cultures with fever cell aggregates. There was negligible cell division during initial 2 days of incubation and cell count increased rapidly between 2 and 8 days. Further incubation beyond 8 days resulted in a decrease in cell viability. Enhanced callus proliferation in Q117 while enhanced shoot regeneration in Co 86032 was observed from cell suspension culture. The clonal fidelity of in vitro regenerated plants was assessed by using RAPD and ISSR markers. Analysis of the ten RAPD markers indicated that 90.48 and 86.95% true-to-type regenerated plantlets in Co 86032 and Q117, respectively. However, in the ISSR markers, Co 86032 did not show any polymorphism and in the Q117, 92.18% true-to-type plantlets were found. These results confirmed that somaclonal variation occurs during the process of indirect organogenesis and RAPD and ISSR marker based molecular analysis is a suitable method for an early detection of variation in sugarcane.

Large-scale production of pharmaceutical proteins in plant cell culture-the Protalix experience

Protalix Biotherapeutics develops recombinant human proteins and produces them in plant cell culture. Taliglucerase alfa has been the first biotherapeutic expressed in plant cells to be approved by regulatory authorities around the world. Other therapeutic proteins are being developed and are currently at various stages of the pipeline. This review summarizes the major milestones reached by Protalix Biotherapeutics to enable the development of these biotherapeutics, including platform establishment, cell line selection, manufacturing process and good manufacturing practice principles to consider for the process. Examples of the various products currently being developed are also presented.

Cytochrome P450 Enzyme Metabolites in Lead Discovery and Development

The cytochrome P450 (CYP) enzymes are a versatile superfamily of heme-containing monooxygenases, perhaps best known for their role in the oxidation of xenobiotic compounds. However, due to their unique oxidative chemistry, CYPs are also important in natural product drug discovery and in the generation of active metabolites with unique therapeutic properties. New tools for the analysis and production of CYP metabolites, including microscale analytical technologies and combinatorial biosynthesis, are providing medicinal chemists with the opportunity to use CYPs as a novel platform for lead discovery and development. In this review, we will highlight some of the recent examples of drug leads identified from CYP metabolites and the exciting possibilities of using CYPs as catalysts for future drug discovery.

Current therapy and drug pipeline for the treatment of patients with acromegaly

INTRODUCTION

Acromegaly is a multisystem disease resulting from chronic exposure to supraphysiological levels of growth hormone (GH), and is associated with significant morbidity and excess mortality. The etiology is almost exclusively an underlying pituitary adenoma. Current therapeutic interventions include surgery, radiotherapy, and medical therapy.

RESULTS

Despite surgery, around 50% of patients fail to achieve the biochemical targets shown to correlate with normalization of mortality rates. Radiotherapy is efficacious in controlling tumor growth and GH secretion; still, achievement of biochemical targets may take up to a decade and a number of safety issues have been raised with this treatment modality. Medical therapy, therefore, has an important role as adjuvant therapy in patients who fail to achieve control with surgery, or while awaiting the effects of radiotherapy to be realized. Furthermore, medical therapy is increasingly being used as primary therapy. Current medical therapies include dopaminergic agonists, somatostatin analogs, and GH receptor (GHR) antagonists. Dopaminergic agonists achieve biochemical targets in up to 30% of patients, and somatostatin analogs in around 60%. The currently available GHR antagonist pegvisomant effectively controls insulin-like growth factor-I levels in over 90% of patients; however, it has no effect on the tumor itself and has considerable financial implications. Research into optimizing the somatostatin and dopaminergic systems has led to promising advances in agonist development. Moieties with selectivity for various combinations of somatostatin receptor subtype receptors have been examined, along with molecules that additionally show high affinity for the dopaminergic D2 receptor. Of the molecules studied in vitro, only pasireotide (SOM230) and BIM-23A760 are currently undergoing further development. Other innovations to improve convenience of currently available drugs are also being investigated.

CONCLUSION

Significant advances in under standing of the somatostatin and dopaminergic system have aided drug development. This may lead to new clinically available therapies enabling control of acromegaly in a larger proportion of patients, and at an earlier stage in their disease management.