Phosphorylation and activation of cell division cycle associated 8 by aurora kinase B plays a significant role in human lung carcinogenesis

Activation of KIF4A as a prognostic biomarker and therapeutic target for lung cancer

PURPOSE AND EXPERIMENTAL DESIGN

To identify molecules that might be useful as diagnostic/prognostic biomarkers and as targets for the development of new molecular therapies, we screened genes that were highly transactivated in a large proportion of 101 lung cancers by means of a cDNA microarray representing 27,648 genes. We found a gene encoding KIF4A, a kinesin family member 4A, as one of such candidates. Tumor tissue microarray was applied to examine the expression of KIF4A protein and its clinicopathologic significance in archival non-small cell lung cancer (NSCLC) samples from 357 patients. A role of KIF4A in cancer cell growth and/or survival was examined by small interfering RNA experiments. Cellular invasive activity of KIF4A on mammalian cells was examined using Matrigel assays.

RESULTS

Immunohistochemical staining detected positive KIF4A staining in 127 (36%) of 357 NSCLCs and 19 (66%) of 29 small-cell lung cancers examined. Positive immunostaining of KIF4A protein was associated with male gender (P = 0.0287), nonadenocarcinoma histology (P = 0.0097), and shorter survival for patients with NSCLC (P = 0.0005), and multivariate analysis confirmed its independent prognostic value (P = 0.0012). Treatment of lung cancer cells with small interfering RNAs for KIF4A suppressed growth of the cancer cells. Furthermore, we found that induction of exogenous expression of KIF4A conferred cellular invasive activity on mammalian cells.

CONCLUSIONS

These data strongly implied that targeting the KIF4A molecule might hold a promise for the development of anticancer drugs and cancer vaccines as well as a prognostic biomarker in clinic.

Cancer-testis antigen lymphocyte antigen 6 complex locus K is a serologic biomarker and a therapeutic target for lung and esophageal carcinomas

Gene expression profile analyses of non-small cell lung carcinomas (NSCLC) and esophageal squamous cell carcinomas (ESCC) revealed that lymphocyte antigen 6 complex locus K (LY6K) was specifically expressed in testis and transactivated in a majority of NSCLCs and ESCCs. Immunohistochemical staining using 406 NSCLC and 265 ESCC specimens confirmed that LY6K overexpression was associated with poor prognosis for patients with NSCLC (P = 0.0003), as well as ESCC (P = 0.0278), and multivariate analysis confirmed its independent prognostic value for NSCLC (P = 0.0035). We established an ELISA to measure serum LY6K and found that the proportion of the serum LY6K-positive cases was 38 of 112 (33.9%) NSCLC and 26 of 81 (32.1%) ESCC, whereas only 3 of 74 (4.1%) healthy volunteers were falsely diagnosed. In most cases, there was no correlation between serum LY6K and conventional tumor markers of carcinoembryonic antigen (CEA) and cytokeratin 19-fragment (CYFRA 21-1) values. A combined ELISA for both LY6K and CEA classified 64.7% of lung adenocarcinoma patients as positive, and the use of both LY6K and CYFRA 21-1 increased sensitivity in the detection of lung squamous cell carcinomas and ESCCs up to 70.4% and 52.5%, respectively, whereas the false positive rate was 6.8% to 9.5%. In addition, knocked down of LY6K expression with small interfering RNAs resulted in growth suppression of the lung and esophageal cancer cells. Our data imply that a cancer-testis antigen, LY6K, should be useful as a new type of tumor biomarker and probably as a target for the development of new molecular therapies for cancer treatment.

Fibroblast growth factor receptor 1 oncogene partner as a novel prognostic biomarker and therapeutic target for lung cancer

To screen candidate molecules that might be useful as diagnostic biomarkers or for development of novel molecular-targeting therapies, we previously carried out gene-expression profile analysis of 101 lung carcinomas and detected an elevated expression of FGFR1OP (fibroblast growth factor receptor 1 oncogene partner) in the majority of lung cancers. Immunohistochemical staining using tumor tissue microarrays consisting of 372 archived non-small cell lung cancer (NSCLC) specimens revealed positive staining of FGFR1OP in 334 (89.8%) of 372 NSCLCs. We also found that the high level of FGFR1OP expression was significantly associated with shorter tumor-specific survival times (P < 0.0001 by log-rank test). Moreover, multivariate analysis determined that FGFR1OP was an independent prognostic factor for surgically treated NSCLC patients (P < 0.0001). Treatment of lung cancer cells, in which endogenous FGFR1OP was overexpressed, using FGFR1OP siRNA, suppressed its expression and resulted in inhibition of the cell growth. Furthermore, induction of FGFR1OP increased the cellular motility and growth-promoting activity of mammalian cells. To investigate its function, we searched for FGFR1OP-interacting proteins in lung cancer cells and identified ABL1 (Abelson murine leukemia viral oncogene homolog 1) and WRNIP1 (Werner helicase interacting protein 1), which was known to be involved in cell cycle progression. FGFR1OP significantly reduced ABL1-dependent phosphorylation of WRNIP1 and resulted in the promotion of cell cycle progression. Because our data imply that FGFR1OP is likely to play a significant role in lung cancer growth and progression, FGFR1OP should be useful as a prognostic biomarker and probably as a therapeutic target for lung cancer.