Colorectal cancer develops in a sequential, evolutionary process, leading to a heterogenic tumor. Comprehensive molecular studies of colorectal cancer have been previously performed; still, the process of carcinogenesis is not fully understood. We utilized gene expression patterns from 94 samples including normal, adenoma, and adenocarcinoma colon biopsies and performed a coexpression network analysis to determine gene expression trajectories of 8,000 genes across carcinogenesis. We found that the majority of gene expression changes occur in the transition from normal tissue to adenoma. The upregulated genes, known to be involved in cellular proliferation, included c-Myc along with its targets. In a cellular model system, we show that physiologic upregulation of c-Myc can lead to cellular proliferation without DNA replication stress. Our analysis also found that carcinogenesis involves a progressive downregulation of genes that are markers of colonic tissue and propose that this reflects a perturbed differentiation of colon cells during carcinogenesis. The analysis of miRNAs targets pointed toward the involvement of miR17 in the regulation of colon cell differentiation. Finally, we found that copy-number variations (CNV) enriched in colon adenocarcinoma tend to occur in genes whose expression changes already in adenoma, with deletions occurring in genes downregulated and duplications in genes upregulated in adenomas. We suggest that the CNVs are selected to reinforce changes in gene expression, rather than initiate them. Together, these findings shed new light into the molecular processes that underlie the transformation of colon tissue from normal to cancer and add a temporal context that has been hitherto lacking. Cancer Res; 74(19); 1–9. ©2014 AACR.

The p21-activated Ser/Thr kinase 1 (PAK1) kinase has an essential role in tumorigenesis and cell survival in many cancers, but its regulation is not fully understood. In this study, we showed that in response to irradiation of lung cancer cells, PAK1 was upregulated, tyrosine phosphorylated, and translocated to the nucleus. Tyrosine phosphorylation relied upon JAK2 kinase activity and was essential for PAK1 protein stability and binding to Snail. This radiation-induced JAK2–PAK1–Snail signaling pathway increased epithelial–mesenchymal transition (EMT) by regulating epithelial and mesenchymal cell markers. Notably, JAK2 inhibitors mediated radiosensitization and EMT blockade in a mouse xenograft model of lung cancer. Taken together, our findings offered evidence that JAK2 phosphorylates and stabilizes functions of PAK1 that promote EMT and radioresistance in lung cancer cells, with additional implications for the use of JAK2 inhibitors as radiosensitizers in lung cancer treatment. Cancer Res; 74(19); 1–12. ©2014 AACR.

NADPH reductase NAD(P)H:quinone oxidoreductase 1 (NQO1) is needed to maintain a cellular pool of antioxidants, and this enzyme may contribute to tumorigenesis on the basis of studies in NQO1-deficient mice. In this work, we sought deeper insights into how NQO1 contributes to prostate carcinogenesis, a setting in which oxidative stress and inflammation are established contributors to disease development and progression. In the TRAMP mouse model of prostate cancer, NQO1 was highly expressed in tumor cells. NQO1 silencing in prostate cancer cells increased levels of nuclear IKKα and NF-κB while decreasing the levels of p53, leading to interactions between NF-κB and p300 that reinforce survival signaling. Gene expression analysis revealed upregulation of a set of immune-associated transcripts associated with inflammation and tumorigenesis in cells in which NQO1 was attenuated, with IL8 confirmed functionally in cell culture as one key NQO1-supported cytokine. Notably, NQO1-silenced prostate cancer cells were more resistant to androgen deprivation. Furthermore, NQO1 inhibition increased migration, including under conditions of androgen deprivation. These results reveal a molecular link between NQO1 expression and proinflammatory cytokine signaling in prostate cancer. Furthermore, our results suggest that altering redox homeostasis through NQO1 inhibition might promote androgen-independent cell survival via opposing effects on NF-κB and p53 function. Cancer Res; 74(19); 1–12. ©2014 AACR.

CCDC134 is a poorly characterized secreted protein that may act as an immune cytokine. Here, we show that CCDC134 is differentially expressed on resting and activated immune cells and that it promotes CD8+ T-cell activation, proliferation, and cytotoxicity by augmenting expression of the T-cell effector molecules IFNγ, TNFα, granzyme B, and perforin. CCDC134 facilitated infiltration of CD8+ T cells with enhanced cytolytic activity into tumors, demonstrating strong antitumor effects in a CD8+ T-cell–dependent manner. Mechanistically, in CD8+ T cells, exposure to CCDC134 promoted cell proliferation through the JAK3–STAT5 pathway, a classic feature of many cytokines of the common γ-chain (γc) cytokine receptor family. Overall, our results provide evidence that CCDC134 may serve as a member of the γc cytokine family and illustrate its potent antitumor effects by augmenting CD8+ T-cell–mediated immunity. Cancer Res; 74(20); 1–12. ©2014 AACR.

CCDC134 is a poorly characterized secreted protein that may act as an immune cytokine. Here we show that CCDC134 is differentially expressed on resting and activated immune cells and that it promotes CD8+ T cell activation, proliferation and cytotoxicity by augmenting expression of the T cell effector molecules IFN-γ, TNF-α, granzyme B and perforin. CCDC134 facilitated infiltration of CD8+ T cells with enhanced cytolytic activity into tumors, demonstrating strong antitumor effects in a CD8+ T cell-dependent manner. Mechanistically, in CD8+ T cells exposure to CCDC134 promoted cell proliferation through the JAK3-STAT5 pathway, a classic feature of many cytokines of the common γ-chain (γc) cytokine receptor family. Overall, our results provide evidence that CCDC134 may serve as a member of the γc cytokine family, and they show illustrate its potent antitumor effects by augmenting CD8+ T cell-mediated immunity.