Apigenin, a common dietary flavonoid, has been shown to induce cell cycle arrest in both epidermal and fibroblast cells and inhibit skin tumorigenesis in murine models. The present study assessed the influence of apigenin on cell growth and the cell cycle in the human colon carcinoma cell lines SW480, HT‐29, and Caco‐2. Treatment of each cell line with apigenin (0–80 μM) resulted in a dose‐dependent reduction in both cell number and cellular protein content, compared with untreated control cultures. DNA flow cytometric analysis indicated that treatment with apigenin resulted in G2/M arrest in all three cell lines in a time‐ and dose‐dependent manner. Apigenin treatment (80 μM) for 48 h produced maximum G2/M arrest of 64%, 42%, and 26% in SW480 cells, HT‐29 cells, and Caco‐2 cells, respectively, in comparison with control cells (15%). The proportion of S‐phase cells was not altered by apigenin treatment in each of the three cell lines. The G2/M arrest was reversible after 48 h of apigenin treatment in the most sensitive cell line SW480. The degree of G2/M arrest by apigenin was inversely correlated with the corresponding inhibition of cell growth measurements in all three cell lines (r = −0.626 to −0.917, P≤0.005). Moreover, an immune complex kinase assay demonstrated an inhibition of p34cdc2 kinase activity, a critical enzyme in G2/M transition, in each cell line after treatment with apigenin (50–80 μM). Western blot analyses indicated that both p34cdc2 and cyclin B1 proteins were also decreased after apigenin treatment. These results indicate that apigenin inhibits colon carcinoma cell growth by inducing a reversible G2/M arrest and that this arrest is associated, at least in part, with inhibited activity of p34cdc2 kinase and reduced accumulation of p34cdc2 and cyclin B1 proteins. Differences in induction of G2/M arrest by apigenin in the three colon carcinoma cell lines suggest that dietary apigenin may be differentially effective against tumors with specific mutational spectra. Mol. Carcinog. 28:102–110, 2000. © 2000 Wiley‐Liss, Inc.

Apigenin, a common dietary flavonoid, has been shown to induce cell cycle arrest in both epidermal and fibroblast cells and inhibit skin tumorigenesis in murine models. The present study assessed the influence of apigenin on cell growth and the cell cycle in the human colon carcinoma cell lines SW480, HT-29, and Caco-2. Treatment of each cell line with apigenin (0-80 microM) resulted in a dose-dependent reduction in both cell number and cellular protein content, compared with untreated control cultures. DNA flow cytometric analysis indicated that treatment with apigenin resulted in G2/M arrest in all three cell lines in a time- and dose-dependent manner. Apigenin treatment (80 microM) for 48 h produced maximum G2/M arrest of 64%, 42%, and 26% in SW480 cells, HT-29 cells, and Caco-2 cells, respectively, in comparison with control cells (15%). The proportion of S-phase cells was not altered by apigenin treatment in each of the three cell lines. The G2/M arrest was reversible after 48 h of apigenin treatment in the most sensitive cell line SW480. The degree of G2/M arrest by apigenin was inversely correlated with the corresponding inhibition of cell growth measurements in all three cell lines (r = -0.626 to -0.917, P

Scholars studying social movements and nongovernmental organizations (NGOs) have noted a rapid expansion in the number of professional organizations dedicated to creating social change. This study uses the case of the peacebuilding sector in Croatia (1991–present) to examine central questions in both fields: where professional organizations come from, what drives professionalization, and what the consequences of professionalization are for the work of social change. I find there are actually many paths to NGO creation, and identify five types of NGOs: transformed, new, bud, seed, and clone. These five types of organizations had different paths for development, have different levels of professionalization, and engage in different types of work based on their location and history. Examining the history of a social change sector shows professionalization to be a nuanced, uneven process that can expand the social change sector even as it transforms the sector's work.

How do new forms of organizations legitimate themselves? Nongovernmental organizations (NGOs) have emerged as a dominant form of civil society organization in the past 35 years, often in societies undergoing social and political transitions. This paper analyzes legitimation processes for NGOs in postwar and postcommunist Croatia using interview and archival data. Starting from a principle that legitimation is a process involving multiple audiences, I examine the mechanisms NGOs use to legitimate themselves to different audiences. I find that Croatian civil society organizations adopted the NGO organizational form to legitimate themselves to international actors, who in turn pressured the Croatian government to accept these organizations as legitimate. However, the actions NGOs took to legitimate themselves to international actors undermined their legitimacy with the Croatian public. This case demonstrates that legitimation is a challenging prospect for a new type of organization, especially given the fragile nature of mediated legitimacy and the conflicting priorities of different audiences.

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