In what could be a significant development, American researchers have found what they believe is an extraordinary link between infection with Covid and cancer regression, where tumours decrease in size or extent – opening up previously unthought-of possibilities for cancer treatment.
Using animals and tissue from humans, the Illinois scientists observed that the RNA molecules of the SARS-CoV-2 virus triggered the development of a special cell in the immune system that has anti-cancer properties.
Known as “inducible nonclassical monocytes” or “I-NCMs”, these special cells attack cancer cells and could be used to treat cancers that are resistant to current therapies, said the Northwestern Medicine Canning Thoracic Institute scientists.
“This discovery opens up a new avenue for cancer treatment,” said Dr Ankit Bharat, the Canning Thoracic Institute’s chief of thoracic surgery.
“We found that the same cells activated by severe Covid-19 could be induced with a drug to fight cancer, and we specifically saw a response with melanoma, lung, breast and colon cancer in the study.”
Bharat was the senior author of the findings published in the The Journal of Clinical Investigation and funded by the National Institutes of Health.
He said that while the research was still in the early stages, with effectiveness only studied in animals, “it offers hope that we might be able to use this approach to benefit patients with advanced cancers that have not responded to other treatments”.
The special cells could be further developed using small molecules, potentially creating a new path for cancer patients who have exhausted traditional treatment methods.
“What makes these cells so special is their dual capability,” Bharat said. “Typically, immune cells called non-classical monocytes patrol blood vessels, looking for threats. But they can’t enter the tumour site itself due to the lack of specific receptors.
“In contrast, the I-NCMs created during severe Covid-19 retain a unique receptor called CCR2, allowing them to travel beyond blood vessels and infiltrate the tumour environment. Once there, they release certain chemicals to recruit body’s natural killer cells. These killer cells then swarm the tumour and start attacking the cancer cells directly, helping to shrink the tumour.”
More research is necessary before their findings could be used in clinical settings, likely to be years away. The next step would be clinical trials.
This year, an estimated 611 720 people will die of cancer in the US – lung cancer being responsible for most of those deaths.
Study details
Inducible CCR2+ nonclassical monocytes mediate the regression of cancer metastasis
Xianpeng Liu, Ziyou Ren, Can Tan et al.
Published in The Journal of Clinical Investigation on 15 November 2024
Abstract
A major limitation of immunotherapy is the development of resistance resulting from cancer-mediated inhibition of host lymphocytes. Cancer cells release CCL2 to recruit classical monocytes expressing its receptor CCR2 for the promotion of metastasis and resistance to immunosurveillance. In the circulation, some CCR2-expressing classical monocytes lose CCR2 and differentiate into intravascular nonclassical monocytes that have anticancer properties but are unable to access extravascular tumour sites. We found that in mice and humans, an ontogenetically distinct subset of naturally underrepresented CCR2-expressing nonclassical monocytes was expanded during inflammatory states such as organ transplant and Covid-19 infection. These cells could be induced during health by treatment of classical monocytes with small-molecule activators of NOD2. The presence of CCR2 enabled these inducible nonclassical monocytes to infiltrate both intra- and extravascular metastatic sites of melanoma, lung, breast, and colon cancer in murine models, and they reversed the increased susceptibility of Nod2–/– mutant mice to cancer metastasis. Within the tumour colonies, CCR2+ nonclassical monocytes secreted CCL6 to recruit NK cells that mediated tumour regression, independent of T and B lymphocytes. Hence, pharmacological induction of CCR2+ nonclassical monocytes might be useful for immunotherapy-resistant cancers.
The Independent article – Covid might cure cancer. No, you didn’t read that wrong (Open access)
See more from MedicalBrief archives:
Covid link to aggressive rare cancers, suggest scientists
Cancer patients with COVID-19 have 13% death rate — CC19 first report