Студент
Мнуар Е.Р., магистр педагогических наук Бекжигитова З.С.
Карагандинский
государственный университет им. Е.А. Букетова
Prospects of gene
therapy in the treatment of oncological diseases
Decisive achievements in molecular biology and genetics to study
the fine structure of eukaryotic genes and their mapping on the chromosomes of
mammals and , especially, humans, the
impressive success of the project "Human Genome" in the
identification and cloning of genes whose mutations cause many hereditary
diseases , and finally , rapid growth in the field of biotechnology and genetic
engineering have become necessary prerequisites to stop animal experiments and
theoretical constructs, and the first attempts at treatment of monogenic
diseases conducted in 1989.
What is gene therapy? Is
it involves treatment with the gene as a drug or medication only by correcting
the mutant gene? These and many other questions will inevitably arise in the
consideration such a promising and potentially dangerous for human medicine of
the future direction of the XXI century, as gene therapy.
Methods and materials. Crucial
prerequisite for successful gene therapy is to ensure effective delivery, that is to say transfection (in a broad sense)
or transduction (by using viral vectors) of foreign gene into target cells,
provision its long-term operation in these cells and the creation of conditions
for the valuable work of the gene (its expression). Transfection can be carried
out by using naked DNA which has been alloyed into the appropriate plasmid, or
complexed DNA (plasmid DNA combined with salts and proteins
(transferrin), also it can be organic polymers (DEAE- dextran, polylysine, liposomes or gold particles), or DNA as part of
viral particles, previously, deprived of the ability to replicate.
Gene therapy as the prospect of a treatment of patients with
cancer.
Maximum number of clinical trials of gene
therapy is not associated with classical hereditary diseases (like hemophilia
or cystic fibrosis), it is associated with cancer treatment. It is simply: they
are very common, intensively studied, it always involve a violation of genetic
control mechanisms for cell division. In addition, gene therapy is often not
aimed at the suppression of the tumor; it aimed on fine-tuning of immune cells
that designed to deal with it. This means that cells can be removed from the
patient's blood and modified in vitro, instead of entering the DNA in the body
and face all difficulties in delivering the desired tissue.
Scientists have discovered a number of defective genes responsible for
the development of cancer, for example, multiple mutated cancer genes (MMAC1),
and defective gene makes suppression of tumor growth and many others important
things. This idea is the replacement of the defective gene patient with healthy
gene. The procedure itself is carried out in several stages. Tissue samples
with the defective gene are taken from the patient and placed in the laboratory
environment, where they can live in vitro. Next, healthy gene is attached to a
special virus that tissue culture specifically “infected”. Viruses used in
connection with their ability to penetrate and embed into the genetic material
of the host cell DNA. Of course it is a special virus that are not able to
reproduce themselves and cause disease, it only intended to accomplish its mission – bring healthy
gene to the nuclear DNA of the patient. After as a healthy gene is inserted
into the DNA of the patient's tissues in the laboratory, carried out the next
stage – cells are returned to the host organism where they breed and increasing
the volume of tissue with a healthy gene.
Therapy of cancer involves many difficulties, including the high resistance
of cancer cells and early metastasis that determining bad prognosis. Necessity
of impact on disseminated throughout the body tumor locus requires systemic
administration of anti-inflammatory drugs that associated with a risk of
exposure to other cells of the body. Rapidly developing gene therapy offers new
methods that allowing enhancing the specificity of effects on cancer cells
while reducing the likelihood of damage to healthy cells. These methods are
under development and are constantly being improved to find the most effective
solutions from
the choice of optimal regulatory elements till
creating based on their structures to find new vectors which is used as natural
viruses and artificially generated genetic material packing system. It can be hoped that as a result there should be a simple and effective
system for the elimination of tumor and its metastases.
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