title: Delineating metabolic signatures of head and neck squamous cell carcinoma: phospholipase A2, a potential therapeutic target.
abstract: A better understanding of molecular pathways involved in malignant transformation of head and neck squamous cell carcinoma (HNSCC) is essential for the development of novel and efficient anti-cancer drugs. To delineate the global metabolism of HNSCC, we report (1)H NMR-based metabolic profiling of HNSCC cells from five different patients that were derived from various sites of the upper aerodigestive tract, including the floor of mouth, tongue and larynx. Primary cultures of normal human oral keratinocytes (NHOK) from three different donors were used for comparison. (1)H NMR spectra of polar and non-polar extracts of cells were used to identify more than thirty-five metabolites. Principal component analysis performed on the NMR data revealed a clear classification of NHOK and HNSCC cells. HNSCC cells exhibited significantly altered levels of various metabolites that clearly revealed dysregulation in multiple metabolic events, including Warburg effect, oxidative phosphorylation, energy metabolism, TCA cycle anaplerotic flux, glutaminolysis, hexosamine pathway, osmo-regulatory and anti-oxidant mechanism. In addition, significant alterations in the ratios of phosphatidylcholine/lysophosphatidylcholine and phosphocholine/glycerophosphocholine, and elevated arachidonic acid observed in HNSCC cells reveal an altered membrane choline phospholipid metabolism (MCPM). Furthermore, significantly increased activity of phospholipase A(2) (PLA(2)), particularly cytosolic PLA(2) (cPLA(2)) observed in all the HNSCC cells confirm an altered MCPM. In summary, the metabolomic findings presented here can be useful to further elucidate the biological aspects that lead to HNSCC, and also provide a rational basis for monitoring molecular mechanisms in response to chemotherapy. Moreover, cPLA(2) may serve as a potential therapeutic target for anti-cancer therapy of HNSCC.
authors: Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI, United States.
authors: Pratima
authors: P
authors: Tripathi
authors: Pachiyappan
authors: P
authors: Kamarajan
authors: Bagganahalli S
authors: BS
authors: Somashekar
authors: Neil
authors: N
authors: MacKinnon
authors: Arul M
authors: AM
authors: Chinnaiyan
authors: Yvonne L
authors: YL
authors: Kapila
authors: Thekkelnaycke M
authors: TM
authors: Rajendiran
authors: Ayyalusamy
authors: A
authors: Ramamoorthy
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000975:Antioxidants / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D002794:Choline / Q000378:metabolism; D002952:Citric Acid Cycle; D005947:Glucose / Q000378:metabolism; D006258:Head and Neck Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D055442:Metabolome; D055432:Metabolomics; D058990:Molecular Targeted Therapy; D064801:Phospholipase A2 Inhibitors; D010743:Phospholipids / Q000378:metabolism; D025341:Principal Component Analysis; D000077195:Squamous Cell Carcinoma of Head and Neck; D014882:Water-Electrolyte Balance
chemical_list: D000596:Amino Acids; D000975:Antioxidants; D064801:Phospholipase A2 Inhibitors; D010743:Phospholipids; D005947:Glucose; D002794:Choline