Natural product-derived Combination therapy for Squamous cell carcinoma of head and neck (HNSCC): A therapeutic mix encompassing  a therapeutic mix encompassing Metformin and Navitoclax/ABT-263   inhibits BMI1 and AP-1 expression, overcomes chemotherapeutic resistance, promotes chemosensitivity, suppresses cancer stem cells in HNSCC, and inhibits lymph node metastasis, via down-regulation of its target genes, 12/February/2017, 10.13 pm