Ultrasound Selectively Kills Oral Cancer Cells, Study Shows
A new study by the Indian Institute of Science (IISc) in Bengaluru has found that low-frequency ultrasound can selectively attack oral cancer cells while leaving healthy cells unharmed. The research, published in the journal 'Materials Today Bio', demonstrates that ultrasound-driven mechanical stimulation induces selective cell death in oral cancer cells derived from patient samples.
Mechanism: Reduced Tropomyosin 2.1 Levels
The vulnerability of cancer cells appears to arise due to reduced levels of Tropomyosin 2.1, a mechanosensory protein that helps cells sense and withstand mechanical stimulation. Healthy oral epithelial cells, which have normal levels of this protein, remained unaffected during the experiments.
"The novelty of this study lies in showing how ultrasound mechanostimulation can selectively target oral cancer cells by exploiting their mechanical weakness," said author Ajay Tijore, assistant professor at the department of bioengineering, IISc. "Instead of using heat or drugs, this approach uses moderate mechanical forces to damage cancer cells beyond their ability to recover."
Study Details and Findings
The team worked with patient-derived oral tumour samples in collaboration with clinicians at MS Ramaiah Medical College and Hospitals. They explored whether low-frequency ultrasound mechanical stimulation could selectively kill oral cancer cells. When exposed to ultrasound-driven mechanical stimulation, oral cancer cells underwent selective cell death, while healthy oral epithelial cells remained unharmed.
The study used low-frequency ultrasound to exploit biomechanical vulnerabilities in oral cancer cells, promoting selective cell death. "Cancer cells are subjected to optimised US (ultrasound) parameters, revealing selective induction of cancer cell apoptosis (mechanoptosis) without harming normal cells," the authors wrote.
Impact on Cancer Cell Migration and Tumor Microenvironment
The team also found that ultrasound drastically reduced the cancer cells' ability to migrate and invade surrounding tissue. Using a 3D co-culture platform mimicking the oral tumour microenvironment, the team discovered that ultrasound disrupted the dense capsule-like barrier formed by cancer-associated cells around the tumour core. This barrier can prevent drugs and immune cells from reaching the tumour core and result in treatment failure.
"What surprised us most was the consistency of the response across cancer cells derived from multiple patients from different cancer stages. They were highly vulnerable to ultrasound, while normal cells were much less affected," said first author Rashmita Luha, a PhD student in the department of bioengineering.
Potential for Clinical Application
Since ultrasound is already approved for varied medical uses, the findings suggest that ultrasound mechanostimulation could exploit the mechanical weakness of oral cancer cells. With further validation in advanced preclinical models, the approach may help develop safer, more targeted treatment strategies for oral cancer and potentially other easily accessible cancers such as breast and skin cancers, the researchers said.
