METHODS: RNA was isolated from peripheral whole blood samples (2 x 10 ml) collected from NPC patients/controls (EDTA vacutainer). Gene expression patterns from 99 samples (66 NPC; 33 controls) were assessed using the Affymetrix array. We also collected expression data from 447 patients with other cancers (201 patients) and non-cancer conditions (246 patients). Multivariate logistic regression analysis was used to obtain biomarker signatures differentiating NPC samples from controls and other diseases. Differences were also analysed within a subset (n=28) of a pre-intervention case cohort of patients whom we followed post-treatment.
RESULTS: A blood-based gene expression signature composed of three genes - LDLRAP1, PHF20, and LUC7L3 - is able to differentiate NPC from various other diseases and from unaffected controls with significant accuracy (area under the receiver operating characteristic curve of over 0.90). By subdividing our NPC cohort according to the degree of patient response to treatment we have been able to identify a blood gene signature that may be able to guide the selection of treatment.
CONCLUSION: We have identified a blood-based gene signature that accurately distinguished NPC patients from controls and from patients with other diseases. The genes in the signature, LDLRAP1, PHF20, and LUC7L3, are known to be involved in carcinoma of the head and neck, tumour-associated antigens, and/or cellular signalling. We have also identified blood-based biomarkers that are (potentially) able to predict those patients who are more likely to respond to treatment for NPC. These findings have significant clinical implications for optimizing NPC therapy.
METHODS: A prospective study spanning 27 months was conducted at the University Hospital, Kuala Lumpur. Serum CEA (Abbott IMx) and serum squamous cell carcinoma antigen (Abbott IMx) from patients clinically suspected of having primary carcinoma of the lung, were assayed using the microparticle enzyme immunoassay method.
RESULTS: Thirty seven cases of histologically confirmed primary lung carcinoma were studied. Of these, 17 were squamous cell carcinomas, 10 adenocarcinomas, nine small cell carcinomas, and one large cell carcinoma. The patients' ages ranged from 34-82 years. The male:female ratio was 3.6:1. Squamous cell carcinoma antigen was raised above the cutoff value of 1.5 ng/ml in 94.1% of squamous cell carcinomas, 20.0% of adenocarcinomas, and 11.1% of small cell carcinomas. By comparison, CEA was raised above the cutoff value of 3.0 ng/ml in 70.6% of squamous cell carcinomas, 77.8% of small cell carcinomas, and 100% of adenocarcinomas. CEA and squamous cell carcinoma antigen were not raised in the patient with large cell carcinoma and in 14 healthy volunteers. None of 15 patients with a variety of benign lung diseases showed a rise of CEA, while two patients--a 25 year old Indian woman with pneumonia and a 64 year old Malay man with bronchial asthma--had raised squamous cell carcinoma antigen values above the cutoff. Serum CEA and squamous cell carcinoma antigen values did not seem to correlate with stage or degree of differentiation of the tumours.
CONCLUSIONS: The findings suggest that CEA is a good general marker for carcinoma, particularly adenocarcinoma. In contrast, squamous cell carcinoma antigen is more specific for squamous carcinoma.
METHODS: PNMA5 mutants were generated through deletion or site-directed mutagenesis and transiently expressed in human cancer cell lines to investigate their role in apoptosis, subcellular localization, and potential interaction with MOAP-1 through apoptosis assays, fluorescence microscopy, and co-immunoprecipitation studies, respectively.
RESULTS: Over-expressed human PNMA5 exhibited nuclear localization pattern in both MCF-7 and HeLa cells. Deletion mapping and mutagenesis studies showed that C-terminus of PNMA5 is responsible for nuclear localization, while the amino acid residues (391KRRR) within the C-terminus of PNMA5 are required for nuclear targeting. Deletion mapping and co-immunoprecipitation studies showed that PNMA5 interacts with MOAP-1 and N-terminal domain of PNMA5 is required for interaction with MOAP-1. Furthermore, co-expression of PNMA5 and MOAP-1 in MCF-7 cells significantly enhanced chemo-sensitivity of MCF-7 to Etoposide treatment, indicating that PNMA5 and MOAP-1 interact synergistically to promote apoptotic signaling in MCF-7 cells.
CONCLUSIONS: Our results show that PNMA5 promotes apoptosis signaling in HeLa and MCF-7 cells and interacts synergistically with MOAP-1 through its N-terminal domain to promote apoptosis and chemo-sensitivity in human cancer cells. The C-terminal domain of PNMA5 is required for nuclear localization; however, both N-and C-terminal domains of PNMA5 appear to be required for pro-apoptotic function.