A combinatorial approach to protect sensory tissue against cisplatin-induced ototoxicity.

Sensorineural Hearing Loss (SNHL) is a highly prevalent disorder involving permanent damage or loss to the inner ear's mechano-sensory hair cells and nerve fibers. Major contributing causes are ototoxic drugs, loud noises, and aging. Drug-induced hearing loss (DIHL), affects over 25% of patients treated with common therapeutics such as aminoglycoside antibiotics, loop diuretics or chemotherapeutics. A commonly used chemotherapeutic agent, cisplatin, is very effective for treating malignant tumors, but results in a majority of patients experiencing irreversible hearing loss and/or tinnitus. Additionally, since there is currently no FDA-approved treatments for SNHL, attenuation of ototoxicity is a major area of investigation in oncology, otolaryngology and hearing research. Several potential otoprotective agents have been investigated at the clinical trial stage, but none have progressed to a full FDA-approval. In this study, we investigated a combinatorial approach comprised of an antioxidant, a p53 inhibitor and a neurotrophin, as a multifactorial otoprotective treatment for cisplatin exposure. In vitro, HEI-OC1 cells, an immortalized organ of Corti epithelial cell line, pre-treated with this biotherapeutic cocktail had significantly reduced cisplatin-induced cell death, DNA fragmentation, and apoptotic activation. In an ex vivo study, rat pup D2-D3 organ of Corti explants, significant protection against cisplatin-based hair cell and neuronal loss was achieved by delivery of the same combinatorial pretreatment. Interestingly, the hair cell protection was localized to the basal and middle regions of the organ of Corti. Together, these findings highlight a novel approach to attenuate cisplatin ototoxicity and potentially prevent DIHL by addressing biological mechanisms of cisplatin ototoxicity.

Resonant Waveguide Grating Imager for Single Cell Monitoring of the Invasion of 3D Speheroid Cancer Cells Through Matrigel.

The invasion of cancer cells through their surrounding extracellular matrices is the first critical step to metastasis, a devastating event to cancer patients. However, in vitro cancer cell invasion is mostly studied using two-dimensional (2D) models. Three-dimensional (3D) multicellular spheroids may offer an advantageous cell model for cancer research and oncology drug discovery. This chapter describes a label-free, real-time, and single-cell approach to quantify the invasion of 3D spheroid colon cancer cells through Matrigel using a spatially resolved resonant waveguide grating imager.

Label-free single cell kinetics of the invasion of spheroidal colon cancer cells through 3D Matrigel.

This article reports label-free, real-time, and single-cell quantification of the invasion of spheroidal colon cancer cells through three-dimensional (3D) Matrigel using a resonant waveguide grating (RWG) imager. This imager employs a time-resolved swept wavelength interrogation scheme to monitor cell invasion and adhesion with a temporal resolution up to 3 s and a spatial resolution of 12 µm. As the model system, spheroids of human colorectal adenocarcinoma HT-29 cells are generated by culturing the cells in 96-well round-bottom ultralow attachment plates. 3D Matrigel is formed by its gelation in 384-well RWG biosensor microplates. The invasion and adhesion of spheroidal HT29 cells is initiated by placing individual spheroids onto the Matrigel-coated biosensors. The time series RWG images are obtained and used to extract the optical signatures arising from the adhesion after the cells are dissociated from the spheroids and invade through the 3D Matrigel. Compound profiling shows that epidermal growth factor accelerates cancer cell invasion, while vandetanib, a multitarget kinase inhibitor, dose-dependently inhibits invasion. This study demonstrates that the label-free imager can monitor in real-time the invasion of spheroidal cancer cells through 3D matrices.