Robot-assisted real-time sentinel lymph node mapping in oral cavity cancer: preliminary experience.

This study aims to assess the feasibility of using indocyanine green and robotic near infra-red fluorescent imaging (Firefly®) for sentinel lymph node biopsy in cN0 oral cavity cancer. Ten patients with early squamous cell carcinoma of the tongue (n = 8) and buccal mucosa (n = 2) were included. Peritumoral injection of 10 mg indocyanine green and real-time mapping of sentinel lymph nodes in the neck was performed using Firefly® via a retro-auricular trans-hairline incision. Sentinel lymph node was detected in all patients at 1.2 sentinel lymph node per person. Majority were situated in level II (91.7%). Mean time to detection of sentinel lymph node was 171.0 (68.0-312.0)s. Mean signal-to-background ratio was 5.62 (3.51-7.91). Frozen section of one sentinel lymph node was positive for malignancy, paraffin section of which confirmed the presence of metastatic disease. Modified radical neck dissection was performed for that particular patient, paraffin section of which did not show any tumor deposit. Frozen section and paraffin section of all other sentinel lymph nodes (n = 11) and neck dissection specimens yielded no malignancy. All resection margins were clear. Three patients completed adjuvant radiotherapy for pT2N0 (n = 2) and pT2N1 (n = 1) carcinoma of the tongue. Mean follow-up was 12.0 (4.0-18.0) months. All patients were alive at last follow-up with no disease recurrence. There were no adverse outcomes associated with the use of indocyanine green and robot-assisted neck dissection. Indocyanine green and Firefly® for sentinel lymph node biopsy in cN0 oral cavity cancer is feasible with no adverse effects.

CD38 triggers inflammasome-mediated pyroptotic cell death in head and neck squamous cell carcinoma.

BACKGROUND: Pyroptosis is a form of inflammatory cell death. Although it is recognized that NLRP3 (nucleotide-binding domain, leucine-rich repeat-containing family, pyrin domain-containing 3) inflammasome is involved in pyroptosis activation, the mechanism by which head and neck squamous cell carcinoma (HNSCC) inhibits pyroptotic cell death remains undefined. This study aims to delineate the role of calcium regulator CD38 in NLRP3 inflammasome-dependent pyroptosis in HNSCC. METHODS: CD38 overexpressing HNSCC cell lines (SAS, CAL27, SNU899) were generated using lentiviral vectors. NLRP3 and gasdermin D (GSDMD) quantity were detected using Western blot. Caspase-1 activity changes were measured using the Caspase-Glo® 1 inflammasome assay. Cell death proportion was determined by flow cytometry analysis. Proliferation assay was performed using xCELLigence RTCA system. Mouse xenotransplantation was performed to evaluate the potential oncogenic or tumor-suppressive function of CD38. ChIP assay was conducted to verify whether transcription factor NFAT1-mediated NLRP3 expression. RESULTS: Exogenous calcium treatment can lead to a significant increase in caspase-1 activity in HNSCC. This feature was also observed in HNSCC cells with stable CD38 overexpression. CD38-overexpressing cell lines showed a significant reduction in proliferation. Further, expression of NLRP3 protein level was significantly increased in CD38-overexpressing cell lines. The N-terminal effector domain of GSDMD was remarkably increased in the CD38-overexpressing HNSCC. ChIP assay indicated that calcium-sensitive transcription factor NFAT1 was possibly involved in the transcriptional upregulation of NLRP3 observed in CD38-overexpressing HNSCC. The pre-clinical xenograft model revealed that CD38 expression had an inhibiting function on HNSCC progression. CONCLUSION: In conclusion, our results suggested that activation of pyroptosis in HNSCC is a calcium-dependent process. Reduced expression of calcium ion regulator CD38 functions could prevent inflammasome-induced pyroptosis in HNSCC. CD38 may function as a tumor suppressor in HNSCC progression.

NADPH oxidase 5α promotes the formation of CD271 tumor-initiating cells in oral cancer.

Oral tongue squamous cell carcinoma (OTSCC) has a distinctive cell sub-population known as tumor-initiating cells (TICs). CD271 is a functional TIC receptor in head and neck cancers. The molecular mechanisms governing CD271 up-regulation remains unclear. Oxidative stress is a contributing factor in TIC development. Here, we explored the potential role of NADPH oxidase 5 (NOX5) and its regulatory mechanism on the development of CD271-expressing OTSCC. Our results showed that the splice variant NOX5α is the most prevalent form expressed in head and neck cancers. NOX5α enhanced OTSCC proliferation, migration, and invasion. Overexpression of NOX5α increased the size of OTSCC xenograft significantly in vivo. The tumor-promoting functions of NOX5α were mediated through the reactive oxygen species (ROS)-generating property. NOX5α activated ERK singling and increased CD271 expression at the transcription level. Also, NOX5α reduces the sensitivity of OTSCC to cisplatin and natural killer cells. The findings indicate that NOX5α plays an important part in the development of TIC in OTSCC.