[Back to Contents Page]
Current Pharmaceutical Biotechnology, Vol. 2, No. 2, 2001
Contents
Possible
Mechanisms for Tumour Cell Sensitivity to TNF-a and Potential Therapeutic Applications. Pp. 119-130
E. Obrador, J. Carretero, J.A. Pellicer
and J. M. Estrela
The
Importance of Drug Delivery to Optimize the Effects of Bone Morphogenetic
Proteins During Periodontal Regeneration. Pp. 131-142.
Gaston N. King
Approaches to Education of Pharmaceutical Biotechnology in Faculties of Pharmacy. Pp. 143-155.
Sema Çalıs , Filiz Öner , Süheyla Kas
and A. Atilla Hıncal
Biotechnology
in the Development of New Vaccines and Diagnostic Reagents Against Tuberculosis
Pp. 157-173.
A. S. Mustafa
Delivery of Bioactive Peptides and Proteins Across Oral (Buccal) Mucosa. Pp. 175-186.
Sevda Senel, Mary Kremer , Katalin Nagy
and Christopher Squier
The Cellular and Molecular Basis of Health Benefits of Grape Seed Proanthocyanidin Extract. Pp. 187-200.
S. S. Joshi C. A. Kuszynski and D. Bagchi
Syntheses and Effect of Bombesin-Fragment6-14 and its Four Analogues on Food Intake in Rats. Pp.201-207.
T. Abiko
and Y. Kimura
Abstracts
[Back to top] Possible Mechanisms for Tumour Cell Sensitivity to TNF-a and Potential Therapeutic Applications
E. Obrador, J. Carretero, J.A. Pellicer and J. M. Estrela
TNF is a macrophage/monocyte-derived cytokine with cytostatic and cytotoxic anti-tumour activity. TNF-a can cause haemorrhagic necrosis and regression of experimental tumours. Nevertheless, the TNF-a doses required to cure tumour-bearing mice lead to injury of normal tissues and, eventually, may cause a lethal shock syndrome. This toxicity implies severe limitations for the therapeutic use of TNF-a. Reactive oxygen intermediates (ROIs) are involved in TNF-a-induced cell killing. Different studies are consistent with the hypothesis that tumour cell sensitivity to TNF-a is related to its capacity to buffer oxidative attack. Recently, we have demonstrated that the sensitivity of Ehrlich ascites tumor (EAT) cells to TNF depends on their glutathione (GSH, the most prevalent nonprotein thiol in mammalian cells) content and their rate of proliferation. This is important because tumour cell populations under active proliferative states may show higher GSH levels, and drug- and/or radiation-resistant tumours have increased cellular levels of GSH. TNF-a induces a shift towards oxidation in the mitochondrial glutathione (mtGSH) status, a fact that is consistent with the hypothesis that mtGSH plays a key role in scavenging TNF-induced ROIs. GSH, which is not synthesized within mitochondria but is neccessary for their normal function, needs to be taken up from the cytosol through a high affinity multicomponent transport system. In consequence, different approaches that lead to depletion of mtGSH may improve the anticancer efficacy of TNF-a both in vitro and in vivo. As an example, EAT-bearing mice fed a glutamine-enriched diet (GED) show a selective increase of glutamate content witihin the tumour cells. Glutamate inhibits GSH uptake by tumour mitochondria and leads to a selective depletion of mtGSH content (not found in mitochondria of normal cells) to approx. 57% of the level found in tumour mitochondria of mice fed a standard diet (SD). Administration of rhTNF-a, which increases generation of mitochondrial ROIs, to EAT-bearing mice fed a SD does not affect significantly the rate of tumour growth. However, when tumour-bearing mice fed a GED where treated with rhTNF-a the number of viable tumour cells was decreased to approx. 38% of controls.
[Back to top] The Importance of Drug Delivery to Optimize the Effects of Bone Morphogenetic Proteins During Periodontal Regeneration
Gaston N. King
Bone
morphogenetic proteins (BMPs) include a large number of proteins belonging to
the TGF-b
superfamily which are characterized by their ability to induce bone and
cartilage formation. Since the isolation and purification of BMPs by
recombinant technology, the effects of single BMPs can now be evaluated in
animal models. Subcutanous placement of a single recombinant BMP, such as
recombinant human (rh) BMP-2, in a rat ectopic assay shows recruitment of
undifferentiated mesenchymal cells, cartilage formation, followed by
replacement with bone, formation of its own bone marrow and physiological bone
remodelling.
The
therapeutic use of recombinant BMPs in the treatment of periodontal disease
(destruction of the tooth ligaments, surrounding bone and tooth cementum, the
latter of which anchors the ligaments to the tooth surface from the adjacent
tooth socket) has attracted considerable interest due to their potent ability
to stimulate intramembranous bone formation without an endochondral
intermediate. Their predictability in stimulating new bone may provide an
alternative that has greater osteogenic potential than autogenous bone, other
growth factors and bone substitutes.
The
biological processes and the potential role of growth factors involved in
promoting regeneration are complicated by the involvement of different cell
types each with their different growth rates and responses to various stimuli.
The major cell types involved in periodontal regeneration include osteoblasts,
cementoblasts and fibroblasts. Here, the formation of the new mineralized
layers on the tooth and bone surfaces by cementoblasts and osteoblasts
respectively are a prerequisite before periodontal ligament formation and
attachment by fibroblasts can occur. In this regard, BMPs are likely candidates
to stimulate periodontal regeneration because of their ability not only to
promote osteogenesis but also to stimulate cementogenesis (new cementum
formation).
However,
understanding when to manipulate each of the various cells differentiation
pathway with the application of single or multiple doses of BMPs at the
appropriate concentration is dependent upon a suitable delivery system that can
be modified in order to optimize its effect during periodontal wound healing.
Furthermore, treatment of intrabony periodontal defects with BMPs are likely to
not only require appropriate temporal release of the agent, but also adaptation
of a carrier that is robust enough to maintain its integrity around the coronal
aspect of the root in order to provide space maintenance and support the
mucoperiosteal flap. This review evaluates the effects of different delivery
systems upon BMP-induced periodontal regeneration.
.
[Back to top] Approaches to Education of Pharmaceutical Biotechnology in Faculties of Pharmacy
Sema Çalıs, Filiz Öner, Süheyla Kas and A. Atilla Hıncal
Pharmaceutical
biotechnology is developing rapidly both in academic institutions and in the
biopharmaceutical industry. For this reason, FIP Special Interest Group of
Pharmaceutical Biotechnology decided to develop a questionnaire concerning
pharmaceutical biotechnology education. After preliminary studies were
completed, questionnaires were sent to the leading scientists in academia and
research directors or senior managers of various Pharmaceutical Biotechnology
Companies in order to gather their views about how to create a satisfactory
program. The objectives of this study were as follows:
-To
review all of the graduate and undergraduate courses which are presently
available worldwide on pharmaceutical biotechnology in Faculties of Pharmacy.
-To
review all of the text books, references and scientific sources available
worldwide in the area of pharmaceutical biotechnology .
When
replying to the questionnaires, the respondents were asked to consider the
present status of pharmaceutical biotechnology education in academia and future
learning needs in collaboration with the biotechnology industry. The data from
various pharmacy faculties and biotechnology industry representatives from
Asia, Europe and America were evaluated and the outcome of the survey showed
that educational efforts in training qualified staff in the rapidly growing
field of pharmaceutical biotechnology is promising. Part of the results of this
questionnaire study have already been presented at the 57th
International Congress of FIP Vancouver, Canada in 1997.
.
[Back to top] Biotechnology in the Development of New Vaccines and Diagnostic Reagents Against Tuberculosis
A. S. Mustafa
Tuberculosis
(TB) is a disease of global concern. About one third of the world population is
infected with Mycobacterium tuberculosis. Every year, approximately 8 million
people get the disease and 2 million die of TB. The currently available vaccine
against TB is the attenuated strain of Mycobacterium bovis, Bacillus Calmette
Guerin (BCG), which has failed to provide consistent protection in different
parts of the world. The commonly used diagnostic reagent for TB is the purified
protein derivative (PPD) of M. tuberculosis, which is nonspecific because of
the presence of antigens crossreactive with BCG and environmental mycobacteria.
Thus there is a need to identify M. tuberculosis antigens as candidates for new
protective vaccines and specific diagnostic reagents against TB. By using the
techniques of recombinant DNA, synthetic peptides, antigen-specific antibodies
and T cells etc., several major antigens of M. tuberculosis have been
identified, e.g. heat shock protein (hsp)60, hsp70, Ag85, ESAT-6 and CFP10 etc.
These antigens have shown promise as new candidate vaccines and/or diagnostic
reagents against TB. In addition, recent comparisons of the genome sequence of
M. tuberculosis with BCG and other mycobacteria have unraveled M. tuberculosis
specific regions and genes. Expression and immunological evaluation of these
regions and genes can potentially identify most of the antigens of M.
tuberculosis important for developing new vaccines and specific diagnostic
reagents against TB. Moreover, advances in identification of proper adjuvant
and delivery systems can potentially overcome the problem of poor
immunogenicity/short-lived immunity associated with protein and peptide based
vaccines. In conclusion, the advances in biotechnology are contributing
significantly in the process of developing new protective vaccines and
diagnostic reagents against TB.
.
[Back to top] Delivery of Bioactive Peptides and Proteins Across Oral (Buccal) Mucosa
Sevda Senel, Mary Kremer Katalin Nagy and Christopher Squier
The
identification of an increasing array of highly potent, endogenous peptide and
protein factors termed cytokines, that can be efficiently synthesized using
recombinant DNA technology, offers exciting new approaches for drug therapy.
However, the physico-chemical and biological properties of these agents impose
limitations in formulation and development of optimum drug delivery systems as
well as on the routes of delivery. Oral mucosa, including the lining of the
cheek (buccal mucosa), floor of mouth and underside of tongue (sublingual
mucosa) and gingival mucosa, has received much attention in the last decade
because it offers excellent accessibility, is not easily traumatized and avoids
degradation of proteins and peptides that occurs as a result of oral
administration, gastrointestinal absorption and first-pass hepatic metabolism.
Peptide
absorption occurs across oral mucosa by passive diffusion and it is unlikely
that there is a carrier-mediated transport mechanism. The principal pathway is
probably via the intercellular route where the major permeability barrier is
represented by organized array of neutral lipids in the superficial layers of
the epithelium. The relative role of aqueous as opposed to the lipid pathway in
drug transport is still under investigation; penetration is not necessarily
enhanced by simply increasing lipophilicity, for other effects, such as charge
and molecular size, also play an important role in absorption of peptide and
protein drugs.
Depending
on the pharmacodynamics of the peptides, various oral mucosal delivery systems
can be designed. Delivery of peptide/protein drugs by conventional means such
as solutions has some limitations. The possibility of excluding a major part of
drug from absorption by involuntary swallowing and the continuous dilution due
to salivary flow limits a controlled release. However these limitations can be
overcome by adhesive dosage forms such as gels, films, tablets, and patches.
They can localize the formulation and improve the contact with the mucosal
surface to improve absorption of peptides and proteins. Addition of absorption
promoters/permeabilizers in bioadhesive dosage forms will be essential for a
successful peptide/protein delivery system
[Back to top] The
Cellular and Molecular Basis of Health Benefits of Grape Seed Proanthocyanidin
Extract
S. S. Joshi, C. A. Kuszynski and D. Bagchi
Red
grape seed extract containing proanthocyanidins and other antioxidants are
being used as nutritional supplements by many health conscious individuals. The
beneficial effects of grape seed proanthocyanidins (GSPE) have been reported,
however, little is known about their mechanism(s) of action. One of the
beneficial effects of GSPE is chemoprevention of cellular damage. The precise
mechanism by which GSPE mediates, chemoprevention is not yet understood. This
report addresses this issue. We investigated the mechanisms of actions of GSPE,
which ameliorates chemotherapy-induced toxic effects of Idarubicin (Ida) and
4,-hydroxyperoxycyclophosphamide (4-HC) in normal human Chang liver cells.
Exposure to GSPE resulted in a significant reduction in apoptosis in response
to the cytotoxicity of chemotherapeutic agents. RT-PCR analysis showed a
significant increase in the anti-apoptotic gene Bcl-2 and a decrease in the
cell cycle associated and proapoptotic genes, c-myc and p53 in cells treated with
GSPE. These results suggest that some of the chemopreventive effects of GSPE
are mediated by upregulating Bcl-2 and down regulating c-myc and p53
genes.
[Back to top] Syntheses and Effect of Bombesin-Fragment6-14 and its Four Analogues on Food Intake in Rats
T. Abiko and Y. Kimura
A
nonapeptide, H-Asn-Gln-Trp-Ala-Val-Gly-His-Leu-Met-NH2,
corresponding to amino acids 6 to 14 of bombesin and its four analogues were
synthesized by a solid-phase method and were tested for their comparative
effect on reducing activity on food intake using male Wistar rats. The
synthetic bombesin-fragment6-14 showed reducing effect on food intake using
male Wistar rats. Of the synthetic analogues, [Phe(4F)13]bombesin-fragment6-14
exhibited the most potent effect. The reducing effect on food intake of [Sar11]bombesin-fragment6-14
was lower than that of our synthetic bombesin-fragment6-14, but the other two
analogues, [bAla11]bombesin-fragment6-14
and [1-Nal8]bombesin-fragment6-14 showed no reducing effect on food
intake in rats.