Geminin ablation in vivo enhances tumorigenesis through increased genomic instability.

Geminin, a DNA replication licensing inhibitor, ensures faithful DNA replication in vertebrates. Several studies have shown that geminin depletion in vitro results in rereplication and DNA damage, whereas increased expression of geminin has been observed in human cancers. However, conditional inactivation of geminin during embryogenesis has not revealed any detectable DNA replication defects. In order to examine its role in vivo, we conditionally inactivated geminin in the murine colon and lung, and assessed chemically induced carcinogenesis. We show here that mice lacking geminin develop a significantly higher number of tumors and bear a larger tumor burden than sham-treated controls in urethane-induced lung and azoxymethane/dextran sodium sulfate-induced colon carcinogenesis. Survival is also significantly reduced in mice lacking geminin during lung carcinogenesis. A significant increase in the total number and grade of lesions (hyperplasias, adenomas, and carcinomas) was also confirmed by hematoxylin and eosin staining. Moreover, increased genomic aberrations, identified by increased ATR and γH2AX expression, was detected with immunohistochemistry analysis. In addition, we analyzed geminin expression in human colon cancer, and found increased expression, as well as a positive correlation with ATM/ATR levels and a non-monotonic association with γH2AX. Taken together, our data demonstrate that geminin acts as a tumor suppressor by safeguarding genome stability, whereas its overexpression is also associated with genomic instability. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Multifunctional LUV liposomes decorated for BBB and amyloid targeting. A. In vitro proof-of-concept.

Multifunctional LUV liposomes (mf-LIPs) were developed, having a curcumin-lipid ligand (TREG) with affinity towards amyloid species, together with ligands to target the transferrin and the LDL receptors of the blood-brain-barrier (BBB), on their surface. mf-LIPs were evaluated for their brain targeting, on hCMEC/D3 monolayers, and for their ability to inhibit Aß-peptide aggregation. The transport of mf-LIP across hCMEC/D3 monolayers was similar to that of BBB-LIPs, indicating that the presence of TREG on their surface does not reduce their brain targeting potential. Likewise, mf-LIP inhibitory effect on Aß aggregation was similar to that of LIPs functionalized only with TREG, proving that the presence of brain targeting ligands does not reduce the functionality of the amyloid-specific ligand. Addition of the curcumin-lipid in some liposome types was found to enhance their integrity and reduce the effect of serum proteins on their interaction with brain endothelial cells. Finally, preliminary in vivo results confirm the in vitro findings. Concluding, the current results reveal the potential of the specific curcumin-lipid derivative as a component of multifunctional LIPs with efficient brain targeting capability, intended to act as a theragnostic system for AD.

Effect of an all-trans-retinoic acid conjugate with spermine on viability of human prostate cancer and endothelial cells in vitro and angiogenesis in vivo.

Retinoids constitute a family of organic compounds that are being used for the treatment of various diseases, ranging from acne vulgaris to acute promyelocytic leukemia. Their use however is limited due to serious adverse effects and there is a great need for analogues with better safety profile. In the present work, the effect of N(1),N(12)-bis(all-trans-retinoyl)spermine (RASP), a conjugate of all-trans-retinoic acid (atRA) with spermine, on angiogenesis in vivo and viability of human endothelial and prostate cancer cells in vitro were studied. Both atRA and RASP dose-dependently inhibited angiogenesis in the chicken embryo chorioallantoic membrane model. RASP was more effective and could be used in a wider dose range due to lower toxicity compared with atRA. Both retinoids decreased the number of human umbilical vein endothelial and prostate cancer LNCaP and PC3 cells in a concentration-dependent manner. RASP was more effective and potent compared with atRA, spermine, their combination, or conjugates of spermine with other acidic retinoids and/or psoralens in prostate cancer cells. The inhibitory effect of both atRA and RASP seems to be related to an increase of the tumour repressing gene retinoic acid receptor beta mRNA, was mediated by retinoic acid receptor alpha, and was proportional to endogenous retinoic acid receptor beta expression. These data suggest that RASP is more effective than atRA in decreasing angiogenesis and prostate cancer cell growth and identify retinoic acid receptor alpha as the receptor through which it causes retinoic acid receptor beta up-regulation and decrease of prostate cancer cell growth.