Thursday, 28th March 2024
To guardian.ng
Search
Breaking News:

New cancer vaccine finds way to overcome tumour defences

By Chukwuma Muanya
21 June 2022   |   4:04 am
Researchers have developed a new vaccine that shows promise in overriding an immune escape mechanism in cancerous tumours. They found that the vaccine offers protection against destructive tumours in mouse and primate cancer models.

cancer vaccine

•Researchers discover single-dose therapy for sickle cell disease

Researchers have developed a new vaccine that shows promise in overriding an immune escape mechanism in cancerous tumours. They found that the vaccine offers protection against destructive tumours in mouse and primate cancer models.

The investigators are planning to enter the vaccine into clinical trials next year. Developing cancer vaccines has been an essential part of research for almost three decades.

Many forms of therapies are under study, including those that target proteins expressed across multiple cancer types and those that are personalised according to individual tumour mutations.

While existing vaccines could induce an immune response in blood, tumors often evade this response via an immune escape mechanism. Targeting this mechanism might help researchers improve vaccine efficacy.

The study, which also showed that the vaccine increases immune antibody levels, was published in Nature. Director of Neuro-Oncology at Providence Saint John’s Health Centre/chair of the Department of Translational Neurosciences and Neurotherapeutics at Saint John’s Cancer Institute in Santa Monica, CA and regional medical director for Research Clinical Institute of Providence Southern California, Dr. Santosh Kesari, who was not involved in the study, explained to Medical News Today how the vaccine works.

He said: “This new approach targets this resistance mechanism by making a vaccine to a general protein that is over-expressed (a stress signal) in cancers, but is rapidly removed by the cancer before the immune system detects it.

“The new vaccine approach prevents the cancer cell from removing this cancer-specific protein and thus allowing a coordinated immune attack on the cancer by both T-cells and natural killer (NK) cells.”

The researchers designed the new vaccine to target MICA and MICB stress proteins, which sit on the surface of cancer cells.
While immune cells in the body, known as T cells and NK cells, typically bind to these stress proteins in an attempt to kill cancerous cells, tumour cells can evade their attack by slicing MICA/B and shedding them.

The new vaccine prevents slicing and thus increases stress protein expression and activation of a dual attack from T cells and NK cells.

To begin, the pollsters administered their new vaccine to mouse models of cancer that were modified to express human MICA/B proteins.

They found that the vaccines increased antibody levels in the mice and demonstrated anti-tumour effects. The investigators then evaluated immunological memory from the vaccine. Four months after initial immunisation, the researchers exposed the mice to tumour cells and discovered that they remained fully protected.

They also found that introducing small quantities of blood from vaccinated mice inhibited cell-surface MICA/B protein shedding on human and mouse cancer cell lines.

The researchers noted that the vaccine was effective in controlling multiple tumour types. They then investigated whether the vaccine could prevent cancer recurrence following surgical tumour removal.

To do so, they immunised mouse models of breast cancer and melanoma with a high chance of recurrence after tumour removal with either the new vaccine or a control vaccine.

They found that, compared to the control vaccine, the new vaccine reduced the number of lung metastases detected in both cancer models more than a month after surgery.

The researchers thereafter tested the vaccine on four rhesus macaques (commonly known as rhesus monkeys). They observed that the vaccine increased antibody levels by 100-1,000 fold with subsequent booster vaccines.

The examiners reported no clinical side effect or change in blood chemistry following immunisation, which, they wrote, suggests preliminary evidence for vaccine safety.

They r concluded that their new vaccine enables protective immunity against tumours with common escape mutations. When asked what the future holds for research around the vaccine, chair of cancer immunology and virology at the Dana-Farber Cancer Institute and lead author, Dr. Kai W. Wucherpfennig, told MNT that they plan to enter the vaccine into clinical trials next year.

ALSO, a study of an investigational gene therapy for sickle cell disease has found that a single dose restored blood cells to their normal shape and eliminated the most serious complication of the ailment for at least three years in some patients.

Four patients at Columbia University Irving Medical Center/New York-Presbyterian participated in the multicentre study, the first to report on such long-term outcomes of a sickle cell gene therapy.

The investigation was published in the New England Journal of Medicine. The single-dose therapy, tested on 35 adults and adolescents with the disease, essentially corrected the shape of the patients’ red blood cells, but also completely eliminated episodes of severe pain, caused when rigid, crescent-shaped red blood cells clump together and block blood vessels. The painful incidents often result in widespread organ damage. Such happenings are a frequent cause of emergency department visits and hospitalisations that lead to early death.

Professor of Medicine at Columbia University Vagelos College of Physicians and Surgeons and co-author, Markus Y. Mapara, said: “You cannot overstate the potential impact of this new therapy. People with sickle cell disease live in constant fear of the next pain crisis. This treatment could give people with this disease their life back. We hope this therapy will also be successful in younger patients so they can grow up without experiencing pain crises and live longer.”

Sickle cell disease is caused by mutations in the beta-globin gene, leading to the production of abnormal hemoglobin, the oxygen-carrying molecule in red blood cells. Normal red blood cells are shaped like donuts, but in sickle cell disease, the abnormal hemoglobin causes red blood cells to stiffen and adopt a spiky, sickle-like shape.

The disease can be cured with a donor bone marrow transplant, but the use of this therapy has the best chance of success in patients, who have a closely matched sibling donor, which is only a minority of patients.

With the new gene therapy, called LentiGlobin, blood-forming stem cells are collected from the patient’s blood. Harmless lentiviruses are then used to deliver a modified copy of the beta-globin gene into the stem cells. When the cells are later re-infused into the patient, they take up residence in the bone marrow and start making healthy new red blood cells.

In the clinical trial, the therapy completely eliminated severe pain crises in the months following infusion (follow-up ranged from four to 38 months) – the longest period in which a gene therapy for sickle cell disease has been studied.

0 Comments