Oral cancer cells might be vulnerable to ultrasound and the technique may help selectively attack them, leaving healthy cells unharmed, a new study by the Indian Institute of Science (IISc) in Bengaluru has found.
The vulnerability appears to arise due to reduced levels of Tropomyosin 2.1, a mechanosensory protein that helps body cells sense and withstand mechanical stimulation, researchers said.
Working with patient-derived oral tumour samples, the team including clinicians at MS Ramaiah Medical College and Hospitals 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, they found. The findings are published in the journal ‘Materials Today Bio’.
“The novelty of this study lies in showing how ultrasound mechanostimulation can selectively target oral cancer cells by exploiting their mechanical weakness," author Ajay Tijore, assistant professor at the department of bioengineering, IISc, said.
“Instead of using heat or drugs, this approach uses moderate mechanical forces to damage cancer cells beyond their ability to recover," Tijore said.
Ultrasound, a non-invasive imaging test, makes use of high-frequency sound waves to create real-time pictures of tissues and organs inside the body.
The study used low-frequency ultrasound to exploit biomechanical vulnerabilities in oral cancer cells, thereby 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.
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 found that ultrasound disrupted the dense capsule-like barrier formed by cancer-associated cells around the tumour core. The 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," first author Rashmita Luha, a PhD student in the department of bioengineering, said.
Since ultrasound is already approved for varied medical uses, the findings suggest 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.
