Targeting colorectal cancer stem cells with inducible caspase-9

Colorectal cancer stem cells (CSCs) drive tumor growth and are suggested to initiate distant metastases. Moreover, colon CSCs are reportedly more resistant to conventional chemotherapy, which is in part due to upregulation of anti-apoptotic Bcl-2 family members. To determine whether we could circumvent this apoptotic blockade, we made use of an inducible active caspase-9 (iCasp9) construct to target CSCs. Dimerization of iCasp9 with AP20187 in HCT116 colorectal cancer cells resulted in massive and rapid induction of apoptosis. In contrast to fluorouracil (5-FU)-induced apoptosis, iCasp9-induced apoptosis was independent of the mitochondrial pathway as evidenced by Bax/Bak double deficient HCT116 cells. Dimerizer treatment of colon CSCs transduced with iCasp9 (CSC-iCasp9) also rapidly induced high levels of apoptosis, while these cells were unresponsive to 5-FU in vitro. More importantly, injection of the dimerizer into mice that developed a colon CSC-iCasp9-induced tumor resulted in a strong decrease in tumor size, an increase in tumor cell apoptosis and a clear loss of CD133+ CSCs. Taken together, our data indicate that dimerization of iCasp9 circumvents the apoptosis block in CSCs, which results in effective tumor regression in vivo

Community Structure of the Parasites of the Endemic Chocolate Chub Squalius carinus Ozulug & Freyhof, 2011 (Cyprinidae) from Isikli Lake, Civril, Turkey

This study presents the first data on parasites of the chocolate chub, Squalius carinus Ozulug & Freyhof, 2011. The composition and the structure of the parasite community infecting this endemic fish from the Isikli Lake are described. A total of 54 specimens of S. carinus are examined; 51 (94.4%) infected by at least one parasite species. In total, 1192 parasite individuals are collected, with mean intensity of 23.4 and mean abundance of 22.1 parasites/fish. The parasite community of S. carinus consists of 14 species: Trichodina sp., Ichthyophthirius multifiliis, Chilodonella cyprini (Protozoa); cysts of Myxobolus sp. (Myxozoa); Dactylogyrus vistulae, Gyrodactylus sp. (Monogenea); Bothriocephalus acheilognathi (Cestoda), metacercariae of Diplostomum sp. and Thylodelphys clavata (Digenea); larvae of Nematoda indet. (Nematoda), Pomphorhynchus sp. (Acanthocephala); Lamproglena pzdchella and Lernaea cyprinacea (Crustacea); and glochidia of Mollusca indet. (Mollusca). The highest dominance index among parasites is recorded for Pomphorhynchus sp. (47.9%), and the lowest for Nematoda indet. (0.3%). The mean species richness of parasite infracommunities is 2.3 species per individual fish. The parasite community of S. carinus is dominated by Pomphorhynchus sp. The remaining parasite species are found with low prevalence and abundance, except for Diplostomum sp. and Dactylogyrus vistulae, which are moderately abundant

Determination of Some Hematological and Non-Specific Immune Defences, Oxidative Stress and Histopathological Status in Rainbow Trout (Oncorhynchus mykiss) Fed Rosehip (Rosa canina) to Yersinia ruckeri

The effect of the Yersinia ruckeri infection in the different tissues of 225 rainbow trout (Oncorhynchus mykiss) fed with rosehip (Rosa canina) was researched by evaluating a range of factors such as hematological and histopathological findings, non-specific immune parameters, liver antioxidant parameters, and then determined mortality and relative percentage survival (RPS) rates

Occurrence of Cystacanths of Pomphorhynchus laevis (Zoega in Muller, 1776) (Acanthocephala) in its Intermediate Host Gammarus obnixus Karaman & Pinkster, 1977 (Am phipoda): A Comparative Study

The amphipod Gammarus obnixus Karaman & Pinkster, 1977 is an intermediate host for the acanthocephalan parasite Pomphorhynchus laevis (Zoega in Muller, 1776). Specimens of G. obnixus were collected from two sampling stations: (1) Isikh Spring (clear, cold water with a fast current and hard substratum with a gravel-covered bottom) and (2) a rainbow trout net-cage area (dense community of macrophytes on a soft substratum due to net-cages residues and high water turbidity). The aim of this study was to determine monthly changes of the larval occurrence of P. laevis and to understand the effect of the fish fanning on the infection rate with cystacanths of P. laevis. A total of 14,027 specimens of G. obnixus were collected. Cystacanths of P. laevis were found in the hemococl of the gammarids. At the Isikli Spring, P. laevis infected 832 (16.2%) of the 5149 G. obnixus examined over the total sampling period and had a mean intensity of the cystacanths of 1.5 and mean abundance 0.2 per amphipod individual. At the netcage area, P. laevis infected 3480 (39.2%) of the 8878 G. obnixus, with a mean intensity of 2.3 and mean abundance 0.9 per amphipod host. Amphipods in all 12 length classes were infected with P laevis. The maximum intensity of the infection was 16 cystacanths of P. laevis in a single G. obnixus in August. Sex ratio of the cystacanths was approximately 1:1. Males of G. obnixus from both stations were more heavily infected than females. The results showed that the population density and infection rates of G. obnixus were higher at the net-cage area than at the Isikli Spring

Mutations in the Ras-Raf Axis Underlie the Prognostic Value of CD133 in Colorectal Cancer

Purpose: High expression of cancer stem cell (CSC) marker CD133 has been used as a predictor for prognosis in colorectal cancer (CRC), suggesting that enumeration of CSCs, using CD133, is predictive for disease progression. However, we showed recently that both CD133 mRNA and protein are not down-regulated during differentiation of colon CSCs, pointing to an alternative reason for the prognostic value of CD133. We therefore set out to delineate the relation between CD133 expression and prognosis. Experimental Design: A CRC patient series was studied for expression of CD133 and other CSC markers by microarray and quantitative PCR analysis. In addition, several common mutations were analyzed to determine the relation with CD133 expression. Results: CD133 mRNA expression predicted relapse-free survival in our patient series, whereas several other CSC markers could not. Moreover, no correlation was found between expression of other CSC markers and CD133. Interestingly, high CD133 expression was related to mutations in K-Ras and B-Raf, and inhibition of mutant K-Ras or downstream mitogen-activated protein kinase kinase (MEK) signaling decreases CD133 expression. In addition, an activated K-Ras gene expression signature could predict CD133 expression in our patient set as well as data sets of other tumor types. Conclusion: CD133 expression is upregulated in CRC tumors that have a hyperactivated Ras-Raf-MEK-ERK pathway and is therefore related to mutations in K-Ras or B-Raf. As mutations in either gene have been related to poor prognosis, we conclude that CD133 expression is not indicative for CSC numbers but rather related to the mutation or activity status of the Ras-Raf pathway. Clin Cancer Res; 18(11); 3132-41. (C) 2012 AAC