Imagine a world where bacteria, typically feared for causing disease, are turned into powerful weapons against cancer. That’s exactly what some scientists are working on. And they are beginning to unravel the mechanisms for doing so, using genetically engineered bacteria to target and destroy cancer cells.
HOW IT WORKS:
These therapies take advantage of the unique ability of certain bacteria to proliferate inside tumors. The low oxygen, acidic and dead tissue in the area around the cancer — the tumor ‘micro-environment’ — create an ideal niche for some bacteria to thrive. Once there, bacteria can, in theory, directly kill tumor cells or activate the body’s immune responses against the cancer. However, several difficulties have hindered the widespread adoption of this approach.
Safety concerns are paramount because introducing live bacteria into a patient’s body can cause harm. Researchers have had to carefully attenuate (weaken) bacterial strains to ensure bacterial strains to ensure they don’t damage healthy tissue. Additionally, controlling the bacteria’s behavior within the tumor and preventing them from spreading to other parts of the body has been difficult.
Bacteria live inside us, known as the microbiome, and treatments, disease and, of course, new bacteria that are introduced can interfere with this natural environment. Another significant hurdle has been our incomplete understanding of how bacteria interact with the complex tumor micro-environment and the immune system.
Questions remain about how to optimize bacterial strains for maximum anti-tumor effects while minimizing side effects. We’re also not sure of the dose — and some approaches give one bacteria and others entire colonies and multiple bug species together.
RECENT ADVANCES:
Despite these challenges, recent advances such as synthetic biology and genetic engineering have breathed new life into the field. Scientists can now program bacteria with sophisticated functions, such as producing and delivering specific anti-cancer agents directly within tumors. This targeted approach could overcome some limitations of traditional cancer treatments, including side-effects and the inability to reach deeper tumor tissues.
Emerging research suggests that bacteria-based therapies could be particularly promising for certain types of cancer. Sold tumors, especially those that have a poor blood supply and are resistant to conventional therapies, might benefit from this approach.
Colon cancer, ovarian cancer, and metastatic breast cancer are among the high-mortality cancers that researchers are targeting with these innovative therapies. These ‘bug drugs’ may also help the body fight cancer by interacting with routinely used immunotherapy drugs.
Recent studies have shown encouraging results. For instance, researchers have engineered strains of E coli bacteria to deliver small tumor protein fragments to immune cells, effectively training them to recognize and attack cancer cells. In lab animals, this approach has led to tumor shrinkage and, sometimes, complete elimination.
SPARING HEALTHY TISSUE:
By exploiting these mechanisms, bacterial therapies can selectively colonize tumors while largely sparing healthy tissues, potentially overcoming limitations of conventional cancer treatments. Ultimately, we need human trials to give us the answer about whether this works, by controlling or eradicating cancer, and, of course, if there are side-effects, its toxicity.
We showed that part of a bacterial cell wall, when injected into patients, could safely help control melanoma — the most deadly form of skin cancer, While we’re still in the early stages, the potential of bacteria-based cancer therapies is becoming increasingly clear. As our understanding of tumor biology and bacteria engineering improves, we may be on the cusp of a new era in cancer treatment.
Bacterial-based cancer therapies take advantage of several unique mechanisms to specifically target tumor cells. As a result, these therapies could offer a powerful new tool in our arsenal against cancer; working in synergy with existing treatments like immunotherapy. While challenges remain the progress in this field offers hope for more effective, targeted treatments that could significantly improve outcomes for cancer patients.
