There have been great improvements made in the sphere of treating patients, yet cancer continues to be regarded as a death sentence. Conventional methodologies such as chemotherapy, surgery and radiotherapy involve traumatizing side effects and may be ineffective in certain situations, which is the reason why these therapeutic techniques seek out means to come up with new approaches such as oncolytic virus therapy.
Oncolytic viral therapy is the cutting edge of cancer treatments that means reactivating the immune response against tumors. These viruses are programmed to replicate only in tumor cells and are capable of destroying normal tissues. But, what exactly is a tumor suppresser virus? How does it work, and what is the reason for its increasing popularity among cancer physicians?
In this blog we give an honest overview of oncolytic viruses and their emerging role in treating cancer. So let us ask ourselves, does this have the potential to revolutionize the current state of practices in the oncological sphere?
Role Of The Oncolytic Virus And Cancer Therapy
Oncolytic viruses are considered revolutionary in cancer therapy because they take advantage of the viral attributes of invading and destroying cells. Nevertheless, oncolytic viruses have been modified or selected so as to exclusively infect and kill only malignant cells and leave normal healthy tissues. With this kind of specificity, this is a much more benign and noninvasive way of treating cancer.
Considering The Roles They Play In Cancer Therapy
- Obliterating Only The Target Cancer Cells
The process of lysing or cell bursting with its associated virus will lead oncolytic viruses to reproduce themselves within cancer cells. This in effect results in both the destruction of the cancerous cell itself while also depositing more tumor associated antigens into the bloodstream.
- Stimulating Immune Response
In the case of destroying the cancerous cells, oncolytic viruses surge over hidden tumor associated antigens to alert the immune system on their existence. Then the stimulation builds up to a powerful anti-tumor immune response ensuring that the body’s natural defense system is being engaged fully to combat the cancerous cells.
- A Coordinated Method
Oncolytic viruses are modified or stably selected so that they preferentially infect tumor cells only, and that is because of the unique tumor microenvironment induced by cancerous tissues like having diminished antivirals and certain surface receptors. For this reason, oncolytic virus therapy is highly selective as it spares intact cells.
- Maximizing Other Therapies’ Effectiveness
Oncolytic viruses can be used alongside chemotherapy, radiation and/or immunotherapy as well. They have potential to increase the sensitivity of these therapies to the affected cells or interact with the approaches to improve therapeutic end results.
- Transportation of Therapeutic Genes
In the case of some oncolytic viruses, the purpose of their engineering is to turn them into vehicles for therapeutic genes. The genes in these viruses encode proteins that can enhance the immune attack or prevent tumor formation, thus further improving the effect of treatment.
- Current Progress
The active research is being done to increase the safety, efficiency, and scope of application of oncolytic viruses. The licensing of T-VEC (Talimogene laherparepvec) for the treatment of melanoma has further enabled and supported development of this form of therapy against other cancers such as lung, liver, and brain.
Oncolytic viruses are more than a medium through which cancer cells can be destroyed; they present a holistic concept of direct tumors cell killing with the use of the immune system and possibly in combination with other treatments.
As more and more studies are conducted, the system of using oncolytic viruses will surely change the landscape of cancer therapy turning it into a more effective and individualized solution.
How Oncolytic Viruses (OVs) Work in Cancer Therapy?
The use of oncolytic viruses (OVs) is an exciting addition in the field of cancer treatment. In essence, these are viruses that have a natural proclivity to infect and kill tumor cells, and similarly, these can also be biologically engineered viruses. The process begins when the OV infects a tumor cell. Tumors cells differ from normal cells in that their immune systems are remarkably robust, thus allowing OVs to penetrate and infect them more easily.
Infection and Replication
Once the OV infects a cancer cell, it replicates in it. The OV’s goal, like any virus, is to reproduce itself, and in order to accomplish this, it exploits the cell and eventually incites its eruption (which is called lysis). Subsequently, tumor antigens are exuded—specific proteins produced by the surface of cancer cells. These antigens are treated as foreign bodies within the body and thus are able to stimulate an immune response.
Activation of the Immune Response
The immune system with its various components including the dendritic cells, T-cells, macrophages, and other cells is activated due to the release of the tumor antigens formed by the tumor cells. It further engages in infiltrating and destroying the cancer-infected cells. Curiously, this immune activation is not limited to the infected cell. The immune system can also be activated to assist the recognition and elimination of nearby, previously uninfected cancer cells. This phenomenon helps to enhance the live imaging-guided targeting of radioactivity to the cancer cells, potentially resulting in distant metastases or residual cancer cells being eradicated.
Integration of oncolytic viruses in cancer Treatment
Oncolytic viruses can be equipped in numerous manners, either as single agents alone or in combination therapies with chemotherapy, radiotherapy and immune checkpoint inhibitors. The objective here is to boost the therapeutic effect of each modality which would in turn lead to an effective and all-encompassing treatment strategy.
- As a Stand Alone Therapy:
In some instances, OVs may be utilized single-handedly and stand as the only treatment option. Given the capacity of the virus to invade and annihilate tumor cells unequivocally, whilst promoting the immune system response simultaneously, there is no need for any additional form of treatment. This characteristic is very useful in the treatment of most of the malignancies responding poorly to conventional therapies.
- Combination Therapy:
Oncolytic Viruses can be administered alongside conventional cancer therapy such as chemotherapy or radiotherapy. These traditional methods can be employed to reduce the size of the tumors, which in turn encourages the oncovirus to infect any left behind cancer cells, this is particularly the case for chemotherapy. Radiation on the other hand can make cancerous cells more sensitive to the oncovirus, which in turn increases effectiveness. This approach often yields better results especially in aggressive or advanced cancer cases.
- Gene-Modified Ovs :
Oncolytic viruses possess this interesting ability to potentially be modified so that the efficacy of targeting and subsequently killing the cancer cells increases, it is one of the best aspects of oncolytic therapy. For instance, particular genes can be insribed into oncolytic viruses which can be transferred within the tumor, causing the production of therapeutic proteins. It is possible for these proteins to strengthen immune system responses, or even further protect the tumor, making it easier for the virus to act upon it. Such a well defined approach can ensure oncoviruses kill as many cancerous cells as possible, with very minimal effect on the non cancerous cells.
- Genome-Wide Alteration:
In addition, there are strategies where oncolytic viruses are engineered in a way to target specific types of enzymes, immunomodulatory cytokines or gene therapies directly to the tumor. This may include pro-drug activating enzymes, or immune system-enhancing cytokines, or some specific interaction sites to be introduction to the gene. This method reduces the dosages used in usually systemic therapies while making the more focused approach on the tumor cells which may lead to a more efficient cancer treatment.
Other Applications of Oncolytic Viruses
Oncolytic viruses comprise a broad spectrum of compounds and a number of specific constructs were developed as part of the engineering approach to target cells. Some of these compounds are clinically infomedicals:immuno therapeutic, efficient and safe drugs for the treatment of patients with non melanoma skin tumors. They include:9
- T-VEC (Talimogene laherparepvec):
T-VEC is an engineered virus based on the herpes simplex virus type 1 which has been approved by FDA for use during the lethitative metastasis. The virus is designed to specifically invade neoplastic cells and is able to be induced to genetically express cytokine GM-CSF which has the desirable antitumor effect. Clinical studies have demonstrated that T-VEC is effective in reducing tumors and improving the patient's survival rate, especially those diagnosed with melanoma-in-situ.
- Vesicular Stomatitis Virus (VSV):
VSV is a Vector, which comes from the rhabdoviridae family and is known to infect a wide range of cells , even cancerous cells! Studies have proven that VSV works even on certain types of cancer that are known to be untreatable. Since cancer cells are the networks that requirements VSV, it has been modified to attack them by self replicating within the cell. Furthermore, it can also boost the immune response that is generated against the tumor which makes it more effective.
- HSV1716:
HSV1716 is a genetically dozed version of the herpes-simplex virus which has been previously used to conduct clinical trials for treating glioblastoma multiforme, melanoma and squamous cell carcinoma. The aim with such viruses during the studies was to allow them to duplicate within the targeted tumor while avoiding any damages to the surrounding healthy tissues. Its effectiveness when used with immune checkpoint inhibitors in order to improve patient conditions to hair loss and even preventing hair loss from occurring has been effectively demonstrated through the clinical trials.
Dr. Pooja Babbar - Expert Medical Oncologist
Dr. Pooja Babbar is a compassionate medical oncologist with over 10 years of experience in this field. She is known for her personalized care and expertise, where she specialized in the treatment of different types of cancer. She is a strong expert in chemotherapy, immunotherapy, and precision oncology treatments.
Dr. Babbar's dedication to providing the best treatment options combined with her patient-centric approach has enabled numerous individuals to confidently and hopefully deal with the challenges of cancer. She has an extensive knowledge of the latest developments in oncology and, thus, is able to offer the most effective and customized treatment plans that guarantee the best quality care.
Her success in curing cancer speaks to her ceaseless efforts at trying to better her patients' lives and assist them in conquering one of life's greatest challenges. Be it managing the toughest cases or simply being an emotional support system, Dr. Pooja Babbar is an ally one can trust while moving toward a successful recovery.
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