Epigenetic Regulation of Elf5 Is Associated with Epithelial-Mesenchymal Transition in Urothelial Cancer

E74-like factor 5 (Elf5) has been associated with tumor suppression in breast cancer. However, its role in urothelial cancer (UC) is completely unknown. Immunohistochemistry (IHC) and methylation specific PCR (MSP) were done to detect Elf5 expression level and its promoter methylation. Results revealed that low expression of Elf5 on protein and mRNA levels were associated with tumor progression, early relapse and poor survival. In vitro, down-regulation of Elf5 can increase epithelial-mesenchymal transition (EMT). Aberrant Elf5 methylation was identified as major mechanism for Elf5 gene silence. Accordingly, restoration of Elf5 by infection or demethylating treatment effectively reversed EMT processes. In conclusion, we identified Elf5 as a novel biomarker of UC on several biological levels and established a causative link between Elf5 and EMT in UC.     

Movement of the tube cell in the lily style in the absence of the pollen grain and the spent pollen tube

Our model proposes that pollen tube growth is a form of cell movement where the tube tip can be considered analogous to a migrating cell which leaves a trail of extracellular matrix (the spent pollen tube) behind. We demonstrate that the tube cell can convey the sperm cells to the ovule and effect fertilization even in the absence of the pollen grain and the spent pollen tube. Adhesion is an integral part of cell attachment and movement in animal systems. We show that in vivo-grown pollen tubes grow beneath the cuticle of the stylar transmitting tract epidermis and directly adhere to one another and the outer wall of the epidermal cells. A fibrous wall material is found to cover the tip of the pollen tube cell wall and the surface of the transmitting tract cells where the two adhere. Fixation methods to preserve adhesive compounds were used. The pollen-tubes grown in vivo, but not in vitro, show star-shaped clusters of F-actin microfilaments in the region back from the tip, as seen by rhodamine-phalloidin staining. These configurations are similar to focal adhesions seen in moving animal cells.     

The Tumor Suppressor pVHL Down-regulates Never-in-Mitosis A-related Kinase 8 via Hypoxia-inducible Factors to Maintain Cilia in Human Renal Cancer Cells

NEK8 (never in mitosis gene A (NIMA)-related kinase 8) is involved in cytoskeleton, cilia, and DNA damage response/repair. Abnormal expression and/or dysfunction of NEK8 are related to cancer development and progression. However, the mechanisms that regulate NEK8 are not well declared. We demonstrated here that pVHL may be involved in regulating NEK8. We found that CAK-I cells with wild-type vhl expressed a lower level of NEK8 than the cells loss of vhl, such as 786-O, 769-P, and A-498 cells. Moreover, pVHL overexpression down-regulated the NEK8 protein in 786-O cells, whereas pVHL knockdown up-regulated NEK8 in CAK-I cells. In addition, we found that the positive hypoxia response elements (HREs) are located in the promoter of the nek8 sequence and hypoxia could induce nek8 expression in different cell types. Consistent with this, down-regulation of hypoxia-inducible factors α (HIF-1α or HIF-2α) by isoform-specific siRNA reduced the ability of hypoxia inducing nek8 expression. In vivo, NEK8 and HIF-1α expression were increased in kidneys of rats subjected to an experimental hypoxia model of ischemia and reperfusion. Furthermore, NEK8 siRNA transfection significantly blocked pVHL-knockdown-induced cilia disassembling, through impairing the pVHL-knockdown-up-regulated NEK8 expression. These results support that nek8 may be a novel hypoxia-inducible gene. In conclusion, our findings show that nek8 may be a new HIF target gene and pVHL can down-regulate NEK8 via HIFs to maintain the primary cilia structure in human renal cancer cells.     

Antibody responses to galectin-8, TARP and TRAP1 in prostate cancer patients treated with a GM-CSF-secreting cellular immunotherapy

A critical factor in clinical development of cancer immunotherapies is the identification of tumor-associated antigens that may be related to immunotherapy potency. In this study, protein microarrays containing >8,000 human proteins were screened with serum from prostate cancer patients (N = 13) before and after treatment with a granulocyte–macrophage colony-stimulating factor (GM-CSF)-secreting whole cell immunotherapy. Thirty-three proteins were identified that displayed significantly elevated (P ≤ 0.05) signals in post-treatment samples, including three proteins that have previously been associated with prostate carcinogenesis, galectin-8, T-cell alternative reading frame protein (TARP) and TNF-receptor-associated protein 1 (TRAP1). Expanded analysis of antibody induction in metastatic, castration-resistant prostate cancer (mCRPC) patients (N = 92) from two phase 1/2 trials of prostate cancer immunotherapy, G-9803 and G-0010, indicated a significant (P = 0.03) association of TARP antibody induction and median survival time (MST). Antibody induction to TARP was also significantly correlated (P = 0.036) with an increase in prostate-specific antigen doubling time (PSADT) in patients with a biochemical (PSA) recurrence following prostatectomy or radiation therapy (N = 19) from in a previous phase 1/2 trial of prostate cancer immunotherapy, G-9802. RNA and protein encoding TARP and TRAP1 was up-regulated in prostate cancer tissue compared to matched normal controls. These preliminary findings suggest that antibody induction to TARP may represent a possible biomarker for treatment response to GM-CSF secreting cellular immunotherapy in prostate cancer patients and demonstrates the utility of using protein microarrays for the high-throughput screening of patient-derived antibody responses.