UC San Diego

Cancer remains a major threat to human health. Utilizing imaging tools including fluorescent proteins and Förster resonance energy transfer-based biosensors, we visualized the molecular events involved in cancer metastasis such as kinases activities at single focal adhesions (FAs) in living cells. Combined with single FA tracking and cross-correlation analysis, we quantified the temporal coordination between the observed kinases activities and FA structural change at single FA resolution, providing new insights into the dynamic coupling between these molecular events that are crucial for cancer cell adhesion. In addition to observational tools, we asked if we could use perturbative tools to reprogram cells to achieve desired therapeutic functions against cancer. Recently, T cells genetically engineered with chimeric antigen receptors (CARs) have shown unprecedented efficacy in treating blood cancers. The CAR T cells possess redirected specificity against tumor cells expressing the target antigens, and are thus effective in recognizing and eliminating target tumor cells. However, the extensive overlap of the antigens between tumor (especially solid tumor) and normal tissues makes it difficult to identify a truly tumor-specific antigen. As a result, the CAR T cells might attack normal tissues expressing low levels of the target antigen and cause severe side effects. To alleviate this “on-target, off-tumor” toxicity, we sought to utilize ultrasound to remotely control the activation of the infused CAR T cells at a confined region and desired time. Focused ultrasound (FUS) can induce temperature increase in biological samples due to internal friction, and has been applied to regulate heat-inducible transgene expression in vivo. While other regulation systems utilizing small molecules or light exist, FUS-based induction method has better spatiotemporal resolution and deeper penetration. We engineered heat-inducible CAR T cells responsive to FUS heating and demonstrated their efficacy in inhibiting tumor growth in vivo after FUS stimulation. We envision that the FUS controllable CAR T therapy will emerge as a powerful treatment for solid tumors, and FUS-based acoustogenetics will become a platform for the remote manipulation of genetics, epigenetics, and cellular functions in living organisms.