Basil Rigas

Effects of nonsteroidal anti-inflammatory drugs on proliferation and on induction of apoptosis in colon cancer cells by a prostaglandin-independent pathway☆

Nonsteroidal anti-inflammatory drugs (NSAIDs) decrease the incidence of and mortality from colon cancer. We observed that NSAIDs inhibit the proliferation rate, alter the cell cycle distribution, and induce apoptosis in colon cancer cell lines. We evaluated whether the inhibition by NSAIDs of prostaglandin (PG) synthesis is required for their effects on colon cancer cells by studying two human colon cancer cell lines: HCT-15 and HT-29. HCT-15, which lacks cyclooxygenase transcripts, does not produce PGs even when exogenously stimulated, whereas HT-29 produces PGE2, PGF2 alpha, and PGI2. HCT-15 and HT-29 cells, when treated for up to 72 hr with 200 microM sulindac sulfide (an active metabolite of sulindac) or 900 microM piroxicam, showed changes in proliferation, cell cycle phase distribution, and apoptosis. Treatment with PGE2, PGF2 alpha, and PGI2, following a variety of protocols, and at concentrations between 10(-6) and 10(-11) M, failed to reverse the effects of NSAIDs on these three parameters of cell growth. We concluded that NSAIDs inhibit the proliferation rate of the two colon cancer cell lines independent of their ability to inhibit PG synthesis. Thus, alternative mechanisms for their activity on tumor cell growth must be entertained. These observations may be relevant to the mechanism of colon tumor inhibition by NSAIDs.

Sulindac sulfide, an aspirin-like compound, inhibits proliferation, causes cell cycle quiescence, and induces apoptosis in HT-29 colon adenocarcinoma cells.

Nonsteroidal antiinflammatory drugs (NSAIDs), have cancer preventive and tumor regressive effects in the human colon. They lower the incidence of and mortality from colorectal cancer and sulindac reduces the number and size of polyps in patients with familial adenomatous polyposis. We studied the effect of sulindac, and its metabolite sulindac sulfide, on the proliferation of HT-29 colon adenocarcinoma cells. Both compounds reduced the proliferation rate of these cells, changed their morphology, and caused them to accumulate in the G0/G1 phase of the cell cycle. These responses were time- and concentration-dependent and reversible. In addition, these compounds reduced the level and activity of several cyclin-dependent kinases (cdks), which regulate cell cycle progression. Sulindac and sulindac sulfide also induced apoptosis in these cells at concentrations that affected their proliferation, morphology, and cell cycle phase distribution. Sulindac sulfide was approximately sixfold more potent than sulindac in inducing these cellular responses. Our results indicate that inhibition of cell cycle progression and induction of apoptotic cell death contribute to the anti-proliferative effects of sulindac and sulindac sulfide in HT-29 cells. These findings may be relevant to the cancer preventive and tumor regressive effects of these compounds in humans.

Curcumin, a natural plant phenolic food additive, inhibits cell proliferation and induces cell cycle changes in colon adenocarcinoma cell lines by a prostaglandin-independent pathway☆

Curcumin, the active ingredient of the rhizome of the plant turmeric (Curcuma longa Linn), a commonly used spice, prevents cancer in animal tumor models. Its mechanism of action is unknown; curcumin may act by inhibiting arachidonic acid metabolism. To explore the mechanism of curcumins chemopreventive effect, we studied its role in proliferation and apoptosis in the HT-29 and HCT-15 human colon cancer cell lines. Curcumin dose-dependently reduced the proliferation rate of both cell lines, causing a 96% decrease by 48 hours. No apoptosis was detected. The antiproliferative effect was preceded by accumulation of the cells in the G2/M phase of cell cycle. The effect of curcumin was similar in both cell lines, which, however, differ in their ability to produce prostaglandins. We conclude that curcumin inhibits colon cancer cell proliferation in vitro mainly by accumulating cells in the G2/M phase and that this effect is independent of its ability to inhibit prostaglandin synthesis. The role of curcumins antiproliferative effect in human colon cancer remains to be established.

Breast-feeding and maternal smoking in the etiology of Crohn's disease and ulcerative colitis in childhood

Medical records concerning pediatric or adolescent patients first diagnosed with Crohns disease or ulcerative colitis in two New York hospitals during a 5-year period (1986 to 1990) were abstracted, and information concerning sex, age, race, birthplace, sibship size, birth order, maternal age at birth, month of birth, duration of breast-feeding, and maternal smoking was recorded. Medical records of patients presenting at the respective pediatric gastroenterology departments immediately before or after the patients with inflammatory bowel disease were seen were also abstracted in order to generate a control series. Data concerning 68 patients with Crohns disease, 39 patients with ulcerative colitis, and 202 control patients were analyzed through multiple logistic regression. Breast-feeding was negatively associated with Crohns disease (P approximately 0.04) and ulcerative colitis (P approximately 0.07), with relative risk point estimates around 0.5 and with evidence of duration-dependent trends in both instances. There was no evidence of association of either disease with maternal age at birth, birth order, maternal smoking, or season of birth.

Altered gastric epithelial cell kinetics in Helicobacter pylori-associated intestinal metaplasia : Implications for gastric carcinogenesis

We have compared apoptosis and proliferation in antral epithelium from individuals not infected with H. pylori (Hp), those with Hp‐induced gastritis and those with Hp‐induced gastritis containing areas of gastric intestinal metaplasia, the precursor lesion to gastric adenocarcinoma. Antral biopsies from 42 patients were assessed for evidence of Hp infection, severity of gastritis and intestinal metaplasia. Apoptosis was evaluated by the TUNEL assay and proliferation by Ki‐67 immunohistochemistry and were expressed as apoptotic (AI) and proliferation (PI) indices. In the 31 Hp‐positive (Hp+) patients, apoptosis and proliferation were increased compared with the 11 Hp‐negative (Hp−) patients (AI = 1.22 ± 0.13% vs. 0.15 ± 0.03%, p < 0.0001; PI = 24 ± 1% vs. 13 ± 2%, p < 0.0001). Increases were proportional to the severity of the inflammation. Within foci of intestinal metaplasia, in 9 of the Hp+ patients, apoptosis was significantly reduced compared with surrounding gastritis (AI = 0.20 ± 0.06% vs. 1.34 ± 0.23%, p = 0.0014), whereas proliferation was not altered (PI = 25.4 ± 4% vs. 24.7 ± 2%, p = 0.87), resulting in a lower AI/PI ratio in intestinal metaplasia than in surrounding gastritis (0.008 ± 0.005 vs. 0.054 ± 0.009, p < 0.02). Hp‐induced gastritis is thus associated with increased epithelial apoptosis and proliferation compared with uninfected controls. In intestinal metaplasia, proliferation remains increased but apoptosis reverts to normal levels, and this perhaps contributes to Hp‐associated gastric carcinogenesis. Int. J. Cancer 85:192–200, 2000. ©2000 Wiley‐Liss, Inc.

Staurosporine inhibits the proliferation, alters the cell cycle distribution and induces apoptosis in HT-29 human colon adenocarcinoma cells

Staurosporine (ST), a potent inhibitor of protein kinase C (PKC), was evaluated for its effect on the proliferation of HT-29 colon adenocarcinoma cells; PKC is associated with increased colon cell proliferation. ST inhibited cell proliferation in a time- and concentration-dependent manner by up to 90%. It also blocked the G2/M phase of the cell cycle and induced classical apoptosis (sub-diploid peak on flow cytometry, DNA ladder, and typical morphological changes). The kinetics of these changes suggest that low ST concentrations (2-20 nM) may act via a different mechanism from higher (100-1000 nM) ones. The role of ST, which is currently evaluated as an antitumor agent, in colon cancer requires further evaluation.

Sulindac sulfide inhibits the proliferation of colon cancer cells: diminished expression of the proliferation markers PCNA and Ki-67

We evaluated the effect of sulindac sulfide (SS), which reduces cell number and induces apoptosis in cultured colon cancer cells (CCCs), on expression of the proliferation markers PCNA and Ki-67 in HT-29 and HCT-15 CCCs; only the former express cyclooxygenases. DNA content and PCNA/Ki-67 expression were analyzed by bivariate flow cytometry. SS inhibited cell proliferation, determined by the reduced expression of PCNA and Ki-67, roughly by half at 72 h, and induced apoptosis (accounting for about two-thirds and one-third of the reduction in cell number, respectively). A similar effect of SS occurred in HT-29 and HCT-15 CCCs, and also in non-colonic cells, indicating that this rather general effect of SS on cultured cells is not dependent on inhibition of prostaglandin synthesis.

Sulindac sulfide alters the expression of cyclin proteins in HT‐29 colon adenocarcinoma cells

Sulindac sulfide (SS), the active metabolite of the colon cancer chemopreventive compound sulindac, inhibits the proliferation of HT‐29 colon cancer cells mainly by inducing cell quiescence. We determined by bivariate flow‐cytometric analysis both the DNA and cyclin protein content of individual cells. Thus, we assessed in detail the expression of several cyclins during the cell‐cycle phases and demonstrated that SS (i) decreases the expression of cyclins B1 and E and (ii) increases the expression of cyclins D1, D2 and D3, particularly in the G1 phase of the cell cycle. SS‐induced apoptotic cells expressed both E‐ and D‐type cyclins but not cyclin B1. The changes in cyclin expression combined with reduced catalytic activity of cyclin‐dependent kinases could explain in molecular terms the anti‐proliferative effect of SS on HT‐29 colon cancer cells. These changes may contribute to the chemopreventive effect of sulindac. Int. J. Cancer 76:99–104, 1998.© 1998 Wiley‐Liss, Inc.

The retinoid fenretinide inhibits proliferation and downregulates cyclooxygenase-2 gene expression in human colon adenocarcinoma cell lines.

Fenretinide [N-(4-Hydroxyphenyl)retinamide, 4-HPR] (10(-10)-10(-6) M) treatment of HT-29 human colon cancer cells for 24-72 h significantly inhibited their growth. Using HCT-15 cells, 4-HPR had limited inhibitory effects on cell proliferation over the same concentration range and time period. The inhibitory effects of 4-HPR on cell growth in HT-29 cells were markedly reduced in the presence of exogenously added prostaglandins (PGs), suggesting a possible role for inhibition of PG synthesis as a mechanism for 4-HPRs antiproliferative effects. Inhibition of PGE(2) production was caused by 4-HPR in a concentration-dependent manner and decreased COX-2 but not COX-1 mRNA levels; this is the first indication that 4-HPR selectively inhibits COX-2 gene expression. Our findings suggest a possible mechanism for the chemopreventive and anti-proliferative effects of 4-HPR.

John Lykoudis: an unappreciated discoverer of the cause and treatment of peptic ulcer disease

discovery of Helicobacter pylori, and their seminal work has revolutionised our understanding of peptic ulcer disease. In an enormous effort spanning over 100 years, investigators have tried to unravel the causes of peptic ulcer disease. Nearly all concentrated on gastric acid. Only a few examined the possibility of an infectious cause. The “bacterial hypothesis” for the causes of peptic ulcer disease was articulated as early as 1875, and since then a small number of investigators has attempted to show a causative role of microorganisms observed in or around peptic ulcers. Some, including Kussmaul in 1868 and Gorham in 1940, advocated the use of bismuth compounds to treat ulcers. Benjamin Burg at Mount Sinai Hospital in New York used partial vagotomy to reduce secondary infections in ulcer margins. Burg’s ideas probably prompted Constance Guion in the neighbouring New York Hospital to prescribe the antibiotic chlortetracycline for peptic ulcer disease in 1946—a practice she later abandoned. These investigators worked in the shadow of the prevailing opinion that hydrochloric acid and the vagus nerve were at the centre of the pathogenesis of peptic ulcer disease. Moynihan best expressed the orthodox medical thinking when he ascribed duodenal ulcer to “the digestion of the duodenal mucosa by the hyperacid gastric juice”. We have come across the efforts of the late John Lykoudis, who in the 1950s concluded that peptic ulcer disease and gastritis had an infectious cause, and who devised an antibiotic treatment that he gave to thousands of patients. We present here a summary of his work as a contribution to the history of peptic ulcer disease. John Lykoudis (1910–80, figure) graduated from the Greek Military Medical School in 1934. In 1938, he started a medical practice in his native Missolonghi, the small town where the English poet Lord Byron fought for Greek independence and eventually died in 1824.