Fig. 8: Synergistically enhancing the therapeutic efficacy of HRH1 signaling blockade in OSCC can be achieved by targeting STAT3 signaling.

Protein levels of phosphorylated (p)-STAT3 and STAT3 in SAS and HSC-3M cells were assessed by Western blotting following HRH1-knockdown (A) or treatment with loratadine (10 µM) for the indicated time points (B). C‒E Different malignant properties, including colony-formation, migration, and invasion abilities, were analyzed in SAS or HSC-3M cells with HRH1 or STAT3 inhibition alone or combined inhibition of both targets using chemical inhibitors (10 µM loratadine and 10 µM C188-9) or shRNAs (shHRH1 and shSTAT3). C: shHRH1 + C188-9, D: loratadine+C188-9, E: shHRH1+shSTAT3. Data are shown as the mean ± standard deviation (SD), n = 2–3, two-tailed Student’s t-test. *p < 0.05, ***p < 0.001 compared to HRH1 or STAT3 inhibition alone. F Protein levels of p-STAT3, STAT3, and EMT-related proteins in SAS and HSC-3M cells were assessed by Western blotting following HRH1-knockdown or combined knockdown of HRH1 and STAT3. G NOD/SCID mice were orthotopically implanted with luciferase-tagged HSC-3M-expressing shCtrl, shHRH1, shSTAT3, or shHRH1+shSTAT3, and luciferase activity was detected twice per week with an IVIS (left panel). Quantitative analysis of the Xenogen imaging signal intensity (photons/s/cm²/sr) is shown in the right panel. Frequencies (H) and mean intensities of signals (I) of cervical lymph node (LN) metastasis by bioluminescent detection at the end of the study. J HSC-3M xenografts with different genetic manipulations described above were isolated to detect expressions of HRH1, p-STAT3, and vimentin by IHC staining. Original magnification, 400 × Scale bar, 30 µm.