In vitro effect of ciprofloxacin on HT-29 human colon carcinoma cell line: assessment of cell proliferation by thymidine uptake and silver nucleolar organizer regions (AgNOR) histomorphometry

Effect of Ciprofloxacin on Susceptibility to Aortic Dissection and Rupture in Mice

Importance

Fluoroquinolones are among the most commonly prescribed antibiotics. Recent clinical studies indicated an association between fluoroquinolone use and increased risk of aortic aneurysm and dissection (AAD). This alarming association has raised concern, especially in patients with AAD with risk of rupture and in individuals at risk for developing AAD.

Objective

To examine the effect of ciprofloxacin on AAD development in mice.

Design, Setting, and Participants

In a mouse model of moderate, sporadic AAD, 4-week-old male and female C57BL/6J mice were challenged with a high-fat diet and low-dose angiotensin infusion (1000 ng/min/kg). Control unchallenged mice were fed a normal diet and infused with saline. After randomization, challenged and unchallenged mice received ciprofloxacin (100 mg/kg/d) or vehicle through daily gavage during angiotensin or saline infusion. Aortic aneurysm and dissection development and aortic destruction were compared between mice. The direct effects of ciprofloxacin on aortic smooth muscle cells were examined in cultured cells.

Results

No notable aortic destruction was observed in unchallenged mice that received ciprofloxacin alone. Aortic challenge induced moderate aortic destruction with development of AAD in 17 of 38 mice (45%) and severe AAD in 9 (24%) but no rupture or death. However, challenged mice that received ciprofloxacin had severe aortic destruction and a significantly increased incidence of AAD (38 of 48 [79%]; P = .001; χ2 = 10.9), severe AAD (32 of 48 [67%]; P < .001; χ2 = 15.7), and rupture and premature death (7 of 48 [15%]; P = .01; χ2 = 6.0). The increased AAD incidence was observed in different aortic segments and was similar between male and female mice. Compared with aortic tissues from challenged control mice, those from challenged mice that received ciprofloxacin showed decreased expression of lysyl oxidase, an enzyme that is critical in the assembly and stabilization of elastic fibers and collagen. These aortas also showed increased matrix metalloproteinase levels and activity, elastic fiber fragmentation, and aortic cell injury. In cultured smooth muscle cells, ciprofloxacin treatment significantly reduced lysyl oxidase expression and activity, increased matrix metalloproteinase expression and activity, suppressed cell proliferation, and induced cell death. Furthermore, ciprofloxacin-a DNA topoisomerase inhibitor-caused nuclear and mitochondrial DNA damage and the release of DNA into the cytosol, subsequently inducing mitochondrial dysfunction, reactive oxygen species production, and activation of the cytosolic DNA sensor STING, which we further showed was involved in the suppression of lysyl oxidase expression and induction of matrix metalloproteinase expression.

Conclusions and Relevance

Ciprofloxacin increases susceptibility to aortic dissection and rupture in a mouse model of moderate, sporadic AAD. Ciprofloxacin should be used with caution in patients with aortic dilatation, as well as in those at high risk for AAD.

Ciprofloxacin decreases survival in HT-29 cells via the induction of TGF-beta1 secretion and enhances the anti-proliferative effect of 5-fluorouracil

BACKGROUND AND PURPOSE

Fluoroquinolones are potent anti-microbial agents with multiple effects on host cells and tissues. Previous studies have highlighted their pro-apoptotic effect on human cancer cells and an immunoregulatory role in animal models of inflammatory bowel disease. We examined the effect of ciprofloxacin on proliferation, cell cycle and apoptosis of HT-29 cells, a human colonic epithelial cell line sensitive to transforming growth factor (TGF)-beta1-mediated growth inhibition and its role in TGF-beta1 production. We also examined the effect of ciprofloxacin on proliferation of HT-29 cells in combination with 5-fluorouracil (5-FU), a well-established pro-apoptotic agent.

EXPERIMENTAL APPROACH

Using subconfluent cultures of HT-29 and Caco-2 cells, we studied the effect of ciprofloxacin, TGF-beta1 and 5-FU on proliferation, apoptosis, necrosis and cell cycle. The effect of ciprofloxacin on TGF-beta1 mRNA expression and production was studied in RNA extracts and cell culture supernatants respectively, using confluent cultures.

KEY RESULTS

Ciprofloxacin decreased proliferation of HT-29 cells in a concentration- and time-dependent manner. This was mediated by accumulation of HT-29 cells into the S-phase but without any effect on apoptosis or necrosis. Additionally, ciprofloxacin enhanced the antiproliferative effect of 5-FU. Interestingly, ciprofloxacin was found to up-regulate TGF-beta1 production by HT-29 cells and its anti-proliferative effect was abolished when TGF-beta1 was blocked. Confirming this mechanism further, ciprofloxacin had no effect on Caco-2, a human colonic epithelial cell line that lacks functional TGF-beta1 receptors.

CONCLUSIONS AND IMPLICATIONS

We demonstrate a novel anti-proliferative and immunoregulatory effect of ciprofloxacin on human intestinal epithelial cells mediated via TGF-beta1.

Histochemical, immunohistochemical and cytogenetic markers in salivary gland tumor pathology

Evaluation of: Adeyemi BF, Kolude BM, Akang EE, Lawoyin JO: A study of silver nucleolar organizer regions in categorization and prognosis of salivary gland tumors. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod. 102, 513-520 (2006). In this study, various confirmed benign and malignant salivary gland tumors underwent a known histochemical silver staining method involving nuclear-associated proteins with diagnostic and prognostic capacity in other malignant tumors. The study examined the methods' ability to differentiate between benign and malignant salivary gland tumors and between different histopathological grades of malignant tumors, and sought correlations between the staining results and staging, metastatic disease and survival. The staining method proved inadequate, confirming many previously published results. This article highlights the growing awareness of pathologists and oral pathologists in developing countries to the uniqueness of salivary gland tumors, and demonstrates their understanding of the importance of both early detection and appropriate treatment.

Ciprofloxacin inhibits cytokine-induced nitric oxide production in human colonic epithelium

BACKGROUND

The fluoroquinolone ciprofloxacin is a broad-spectrum antibiotic that has been used in the treatment of inflammatory bowel diseases. There is evidence that quinolones have immunomodulating activities via the regulation of cytokine production.

MATERIALS AND METHODS

We investigated the effect of ciprofloxacin on the nitric oxide (NO) production by colonic epithelium. HT-29 cells and colonic biopsies from patients (n = 4) with ulcerative colitis (UC) and normal controls (n = 4) were cultured with various concentrations of ciprofloxacin (10-100 microg mL(-1)) in the presence and absence of pro-inflammatory cytokines. The production of NO was measured in culture supernatants with a spectrophotometric method and inducible nitric oxide synthase (iNOS) mRNA expression was examined by reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Ciprofloxacin did not have any effect on the basal NO production by HT-29 cells. In contrast, ciprofloxacin significantly (P < 0.001) inhibited the pro-inflammatory cytokines (interleukin-1alpha + tumour necrosis factor-alpha + interferon-gamma)-induced NO production in HT-29, in a concentration-dependent manner, via the inhibition of the cytokine-induced iNOS mRNA expression. Wortmannin produced a concentration related reversal of the inhibitory effect of ciprofloxacin at both iNOS mRNA expression and NO production in HT-29 cells. A similar inhibitory effect of ciprofloxacin on the cytokine-induced NO production and iNOS mRNA expression was detected in vitro in cultures of normal colonic tissue. In addition, ciprofloxacin significantly inhibited the NO production and iNOS mRNA expression in cultures of colonic tissue from ulcerative colitis patients, in a concentration-dependent manner.

CONCLUSIONS

These data suggest that ciprofloxacin, in addition to its antimicrobial role, might have an immunoregulatory effect on intestinal inflammation, via the modulation of inflammatory mediators.

Age-related changes in proliferative markers in labial salivary glands: a study of argyrophilic nucleolar organizer regions (AgNORs) and Ki-67

The aim of the present study was to examine age-related changes in the proliferative capacity of acinar and ductal cells in labial salivary glands of healthy subjects as reflected by AgNOR and Ki-67 parameters. The study was conducted on 24 postmortem samples of labial salivary glands free from salivary gland tumors/diseases. Samples were equally divided into three age groups: young (mean age 17 yr), adult (mean age 38 yr) and old (mean age 84 yr). The number of profiles of AgNOR (nNOR) and AgNOR profile area per nucleus (TVNOR) were histomorphometrically assessed by CUE-3 automatic image analyzer on 30 nuclei of acinar and intercalated ductal cells in each age group. The percentage of Ki-67 positively stained acinar and ductal cells was evaluated histomorphometrically. Statistical analysis was carried out by one-way ANOVA and Kruskal-Wallis tests. In the acinar cells, nNOR increased significantly with aging (p<0.00001), while TVNOR did not change significantly. In the ductal cells, both nNOR and TVNOR increased significantly (p<0.00001) with a relatively higher increase in TVNOR. Since only isolated acinar and ductal cells demonstrating Ki-67 positive nuclei were found in the different age groups, the overall proliferation index was estimated to be 0%. Thus, it is suggested that age-related changes in AgNOR parameters could reflect changes in the metabolic cell activity rather than changes in their proliferative capacity. In this context, AgNOR results are in accordance with the histomorphometric and physiologic age-related changes occurring in labial salivary glands.