Targeting c-MYC and gain-of-function p53 through inhibition or degradation of the kinase LZK suppresses the growth of HNSCC tumors

Discovery of potent and selective PROTACs for the protein kinase LZK for the treatment of head and neck cancer

Leucine zipper-bearing kinase (LZK) is overexpressed in 20% of head and neck squamous cell carcinoma (HNSCC) cases and has emerged as a promising therapeutic target in this cancer subtype. LZK promotes HNSCC survival and proliferation by stabilizing c-MYC and GOF-p53 in kinase-dependent and -independent manners, respectively. Herein, we developed a new series of LZK degraders utilizing proteolysis-targeting chimera (PROTAC) technology by modulating the linker region or LZK warhead of LZK-targeting PROTAC-21A, previously developed by our laboratory. Among the 27 PROTACs synthesized and tested, PROTAC 17 was found to be the most potent, degrading LZK at 250 nM and suppressing HNSCC viability at 500 nM. In summary, our lead PROTAC effectively targeted LZK for proteasomal degradation and inhibited oncogenic activity in HNSCC cell lines with amplified LZK.

Advancing Head and Neck Cancer Therapies: From Conventional Treatments to Emerging Strategies

Head and neck cancers (HNCs), particularly head and neck squamous cell carcinoma (HNSCC), are among the most aggressive and prevalent malignancies of the upper aerodigestive tract. As the incidence of HNCs continues to rise, this cancer type presents a significant public health challenge. Despite conventional treatment options, such as surgery, chemotherapy, and radiotherapy, the five-year survival rates remain relatively low due to resistance to these therapies, local recurrence, local lymph node metastasis, and in some advanced cases also distant metastasis. Consequently, patients with HNCs face a high mortality risk and have reduced quality of life due to the side effects of chemo- and radiotherapy. Furthermore, targeted therapies and immunotherapies have also shown limited effectiveness in many cases, with issues related to resistance and the accessibility of these treatments. Therefore, new strategies, such as those based on combination therapies and nanotechnology, are being explored to improve the treatment of HNC patients. The proteolysis-targeting chimeras (PROTACs) also emerged as a promising therapeutic approach, though research is still ongoing to bring this technology into clinical practice. Here, we aim to highlight the current knowledge of HNC therapies, with a focus on recent advancements, including nanomedicine and PROTAC-based strategies. The development and advancement of novel emerging therapies hold promise for the improvement of patients' survival and quality of life.