Photothermal detection of nicotine-induced apoptotic effects in pancreatic cancer cells

Nicotine exacerbates liver damage in a mice model of Ehrlich ascites carcinoma through shifting SOD/NF-κB/caspase-3 pathways: ameliorating role of Chlorella vulgaris

Nicotine, a pervasive global environmental pollutant, is released throughout every phase of the tobacco's life cycle. This study examined the probable ameliorative role of Chlorella vulgaris (ChV) extract against nicotine (NIC)-induced hepatic injury in Ehrlich ascites carcinoma (EAC) bearing female Swiss mice. Sixty female Swiss mice were assigned to four equal groups orally gavaged 2% saccharin 0.2 mL/mouse (control group), orally intubated 100 mg ChV /kg (ChV group), orally intubated 100 µg/mL NIC in 2% saccharin (NIC group), and orally intubated NIC + ChV as in group 3 and 2 (NIC+ChV group). The dosing was daily for 4 weeks. Mice from all experimental groups were then inoculated intraperitoneally with viable tumor cells 2.5 × 106 (0.2 mL/mouse) in the fourth week, and the treatments were extended for another 2 weeks. The results have shown that NIC exposure significantly altered the serum levels of liver function indices, lipid profile, LDH, and ALP in the NIC-exposed group. NIC administration significantly increased hepatic inflammation, lipid peroxidation, and DNA damage-related biomarkers but reduced antioxidant enzyme activities. NIC exposure downregulated SOD1, SOD2, CAT, GPX1, and GPX2 but upregulated NF-κB hepatic gene expression. Notably, the presence of the EAC cells outside the liver was common in all mice groups. Liver tissue of the NIC-exposed group showed multifocal expansion of hepatic sinusoids by neoplastic cells. However, with no evidence of considerable infiltration of EAC cells inside the sinusoids or in periportal areas in the NIC + ChV groups. NIC significantly altered caspase-3, Bax, and BcL2 hepatic immune expression. Interestingly, ChV administration significantly mitigates NIC-induced alterations in hepatic function indices, lipid profile, and the mRNA expression of antioxidant and NF-κB genes and regulates the caspase-3, Bax, and BcL2 immunostaining. Finally, the in vivo protective outcomes of ChV against NIC-induced hepatic injury combined with EAC in female Swiss mice could suggest their helpful role for cancer patients who are directly or indirectly exposed to NIC daily.

Pathophysiological Events Associated With Pancreatitis in Response to Tobacco: An In Vitro Comparative Study With Ethanol in Primary Acinar Cell Culture

OBJECTIVES

The aim of this study was to comparatively analyze the effects of different concentrations of cigarette smoke condensate (CSC, a standardized tobacco extract) and ethanol on intracellular enzyme activation, cell necrosis, alteration of cytosolic calcium concentration ([Ca]c), and amylase secretion in pancreatic acinar cells.

METHODS

The effects of CSC (1 μg/mL to 0.4 mg/mL) and ethanol (10-100 mM) on intracellular enzyme activity, cell necrosis, and [Ca]c were measured by fluorescence assays in isolated pancreatic acinar cells. Amylase secretion was evaluated by spectrophotometry. Supramaximal concentrations of cholecystokinin (10-100 nM) were used as positive control.

RESULTS

Neither CSC nor ethanol induced trypsin or elastase activation. Both CSC (0.1-0.4 mg/mL) and ethanol (10-75 mM) significantly increased [Ca]c. Amylase secretion was increased only in CSC-treated cells (0.3 and 0.4 mg/mL). After 60 minutes, CSC (0.3 and 0.4 mg/mL) significantly increased acinar cell necrosis at a similar percentage to that induced by cholecystokinin. Ethanol did not induce any significant cell necrosis.

CONCLUSIONS

Cigarette smoke condensate induces acinar cell injury and increases [Ca]c and amylase secretion, independently of intracellular enzyme activation, suggesting that tobacco could induce several main early events of pancreatitis in pancreatic acinar cells. However, ethanol only induces increases [Ca]c, having no effect on cell injury, amylase secretion, or intracellular enzyme activation.

Expression Changes of Apoptotic Genes in Tissues from Mice Exposed to Nicotine

Objective:

Smoking is the leading preventable cause of various diseases such as lung cancer, chronic obstructive pulmonary disease and cardiovascular disease. Nicotine, one of the major toxic components of tobacco, contributes to the pathogenesis of different diseases.

Methods:

Given the controversy about nicotine toxicity, the present study was conducted to determine apoptotic effects of nicotine on the heart, kidney, lung and liver of male mice. Real-time PCR was performed to identify mRNA expression changes in apoptotic-related genes between nicotine treated and control mice.

Result:

In the heart and lung, nicotine caused significant decrease in P53, Bax and Caspase-3 mRNA expression levels compared to the control group. However, in the kidney and liver, the result was significant increase in Bax, Caspase-2, Caspase-3 and a significant decrease in P53 mRNA expression (p<0.01). DNA fragmentation assays indicated no fragmentation in the heart and lung, but in the kidney and liver of nicotine treated mice, isolated DNA was fragmented.

Conclusion:

Our study provided insight into the molecular mechanisms of nicotine anti-apoptotic effects on the heart and lung as well as pro-apoptotic effects on kidney and liver via a P53-independent pathway.

Ultrasensitive label-free photothermal imaging, spectral identification, and quantification of cytochrome c in mitochondria, live cells, and solutions

Light-absorbing endogenous cellular proteins, in particular cytochrome c, are used as intrinsic biomarkers for studies of cell biology and environment impacts. To sense cytochrome c against real biological backgrounds, we combined photothermal (PT) thermal-lens single-channel schematic in a back-synchronized measurement mode and a multiplex thermal-lens schematic in a transient high resolution (ca. 350 nm) imaging mode. These multifunctional PT techniques using continuous-wave (cw) Ar+ laser and a nanosecond pulsed optical parametric oscillator in the visible range demonstrated the capability for label-free spectral identification and quantification of trace amounts of cytochrome c in a single mitochondrion alone or within a single live cell. PT imaging data were verified in parallel by molecular targeting and fluorescent imaging of cellular cytochrome c. The detection limit of cytochrome c in a cw mode was 5 x 10(-9) mol/L (80 attomols in the signal-generation zone); that is ca. 10³ lower than conventional absorption spectroscopy. Pulsed fast PT microscopy provided the detection limit for cytochrome c at the level of 13 zmol (13 x 10(-21) mol) in the ultrasmall irradiated volumes limited by optical diffraction effects. For the first time, we demonstrate a combination of high resolution PT imaging with PT spectral identification and ultrasensitive quantitative PT characterization of cytochrome c within individual mitochondria in single live cells. A potential of far-field PT microscopy to sub-zeptomol detection thresholds, resolution beyond diffraction limit, PT Raman spectroscopy, and 3D imaging are further highlighted.

Real-time electrical impedance detection of cellular activities of oral cancer cells

In this study, the electric cell-substrate impedance sensing (ECIS) system was used to study the cellular activities of oral squamous cell carcinoma (OSCC) cells in a real-time and label-free manner. Various cellular activities, including cell adhesion, spreading, proliferation, and drug-induced apoptosis and inhibition of apoptosis, were monitored. A linear relationship was found between the impedance-based cell index and the cell number in the range of 3500 to 35,000 cells/well. Anti-cancer drug-cisplatin-induced OSCC cell apoptosis at the minimal concentration of 5 microM after 20 h of treatment and followed a linear dose-dependent manner in the concentration range from 10 microM to 25 microM. The inhibition of cisplatin-induced apoptosis by the carcinogen, nicotine, at concentrations from 0.1 microM to 10 microM was monitored. The most significant inhibitory effect of nicotine on cisplatin-induced apoptosis was observed at concentrations of 0.5-1 microM. The results obtained with impedance method correlated well with microscopic imaging analysis of cellular morphology and cell viability analysis. This study demonstrated that the impedance-based method can provide real-time information about the cellular activity of viable cells and detect drug-induced cellular activities much earlier than commonly used cell-based image analysis. This impedance-based method has the potential to provide a useful analytical approach for cancer research.

Optical microscopy in photosynthesis

Emerging as well as the most frequently used optical microscopy techniques are reviewed and image contrast generation methods in a microscope are presented, focusing on the nonlinear contrasts such as harmonic generation and multiphoton excitation fluorescence. Nonlinear microscopy presents numerous advantages over linear microscopy techniques including improved deep tissue imaging, optical sectioning, and imaging of live unstained samples. Nonetheless, with the exception of multiphoton excitation fluorescence, nonlinear microscopy is in its infancy, lacking protocols, users and applications; hence, this review focuses on the potential of nonlinear microscopy for studying photosynthetic organisms. Examples of nonlinear microscopic imaging are presented including isolated light-harvesting antenna complexes from higher plants, starch granules, chloroplasts, unicellular alga Chlamydomonas reinhardtii, and cyanobacteria Leptolyngbya sp. and Anabaena sp. While focusing on nonlinear microscopy techniques, second and third harmonic generation and multiphoton excitation fluorescence microscopy, other emerging nonlinear imaging modalities are described and several linear optical microscopy techniques are reviewed in order to clearly describe their capabilities and to highlight the advantages of nonlinear microscopy.

Nicotine and apoptosis

Cigarette smoking is associated with a plethora of different diseases. Nicotine is the addictive component of cigarette but also acts onto cells of the non-neuronal system, including immune effector cells. Although nicotine itself is usually not referred to as a carcinogen, there is ongoing debate whether nicotine functions as a 'tumor enhancer.' By binding to nicotinic acetylcholine receptors, nicotine deregulates essential biological processes like angiogenesis, apoptosis, and cell-mediated immunity. Apoptosis plays critical roles in a wide variety of physiologic processes during fetal development and in adult tissue and is also a fundamental aspect of the biology of malignant diseases. This review provides an overlook how nicotine influences apoptotic processes and is thus directly involved in the etiology of pathological conditions like cancer and obstructive diseases.

Dysfunction of the pancreas in healthy smoking persons and patients with chronic pancreatitis

OBJECTIVES

The aim of the study was to assess the effect of cigarette smoking on the endocrine pancreatic function by determining the levels of serum glucose and plasma insulin as well as by defining immunohistochemical localization of insulin and glucagon in tissue specimens of the pancreata derived from healthy persons and smoking and nonsmoking patients with diagnosed chronic pancreatitis (CP).

METHODS

The oxidative method was used to measure fasting glycemia in blood plasma and the method enzyme-linked immunoassay to determine the level of insulin in plasma. Immunohistochemical localization of hormones in paraffin tissue specimens of the pancreas was performed using the LSAB2-HRP visual test with polyclonal insulin and glucagon antibodies. The intensity of immunohistochemical reaction was calculated with digital imaging methodology.

RESULTS

The study revealed a substantially higher level of serum glucose in smoking CP patients and in healthy persons compared with nonsmoking patients and healthy persons, whereas insulin concentration in smoking patients was statistically lower than in nonsmokers. Smoking patients showed significantly lower expression of insulin and glucagon in the pancreas compared with nonsmoking patients and healthy persons.

CONCLUSIONS

Impairment of the endocrine function of beta and alpha cells in the pancreatic islets is frequently manifested by complications in pancreatitis resulting among others from long-term smoking.

Superhigh-sensitivity photothermal monitoring of individual cell response to antitumor drug

We describe and explore the capability of a photothermal (PT) assay with modified schematics for highly sensitive detection of individual cell response to antitumor drug impact in vitro. Specifically, we used the nonlinear differential PT test to measure distinctive changes of specific PT parameters after exposure of KB3 carcinoma cells to the antitumor drug vinblastine in the broad concentration range of 10(-10) to 300 nM. Verification of the PT assay was performed by comparison with multidrug-resistant cells and comparison with conventional assays evaluating cell viability, cytochrome c release, apoptosis induction, and cell size. We demonstrate that this system is capable of detecting drug-induced signals at a concentration threshold sensitivity at least seven orders of magnitude better than existing assays. We anticipate that this technique may serve as a convenient and rapid analytical tool to evaluate the presence of intracellular drug, with applications in high throughput screening assays and for studying drug uptake and distribution in more complex biological or clinical samples.

[Effects of nicotine with special consideration given to tumorigenesis in the head and neck region]

BACKGROUND

Tumorigenesis is based on initiation, promotion, and progression, whereas tobacco smoke is a decisive predisposing factor for squamous cell carcinomas of the upper aerodigestive tract. A variety of tobacco smoke compounds is known to potentially initiate tumors, but the alkaloid nicotine is generally considered to induce addiction only. However, there is growing evidence that nicotine may also contribute to early stages of tumorigenesis. In the present study, a possible direct genotoxic potential of nicotine is investigated.

MATERIAL AND METHODS

Lymphatic tissue of the tonsilla palatina of eight donors was harvested during surgery and incubated with nicotine. DNA damage was measured with the comet assay.

RESULTS

Genotoxic effects of nicotine could be demonstrated.

DISCUSSION

The results suggest a direct contribution of nicotine to tumor initiation and carcinogenesis.

Comorbid alcohol and nicotine dependence: from the biomolecular basis to clinical consequences

This article represents the proceedings of a symposium presented at the 12th Congress of the International Society for Biomedical Research on Alcoholism held in Heidelberg/Mannheim, Germany, on October 1, 2004. The organizers and cochairs were Nassima Ait-Daoud, MD, and Gerhard A. Wiesbeck, MD. The presentations included the following:L (1) The Role of Nicotinic Acetylcholine Receptors in Alcohol-Seeking Behavior, by Przemyslaw Bienkowski, MD, PhD; (2) Utilization of Linkage Analysis Combined with Microarray Technology to Identify Genes and Mechanisms Underlying Nicotine and Alcohol Use and Abuse in Humans and Rodents, by Ming D. Li, PhD; (3) Smoking and Alcoholic Chronic Pancreatitis: The Underestimated Risk?, by Roland H. Pfützer, MD; (4) Anticraving Medication in Alcohol and Nicotine Dependence, by Otto M. Lesch, MD, PhD; and (5) Pharmacotherapy for Promotion of Abstinence from Nicotine Among Alcohol-Dependent Individuals, by Bankole A. Johnson, DSc, MD, PhD.

Chronic pancreatic inflammation induced by environmental tobacco smoke inhalation in rats

OBJECTIVE

Despite a strong epidemiological association between cigarette smoking and pancreatic diseases, such as pancreatic cancer and chronic pancreatitis, the effects of long-term cigarette smoke inhalation on the pancreas have not been clearly determined. In the present study, we investigated the effect of cigarette smoke inhalation on the pancreas.

METHODS

Thirty-six female Sprague Dawley rats were exposed to two different doses of environmental tobacco smoke averaging 100 mg or 160 mg/m3 total suspended particulate matter (TSP) per m3 for 70 min twice a day for 12 wk. The animals were sacrificed and examined for the effects of tobacco smoke exposure on pancreatic morphology and function.

RESULTS

In 58% (7/12) of the animals, exposure to 160 mg/m3 TSP cigarette smoke induced a chronic pancreatic inflammatory process with fibrosis and scarring of pancreatic acinar structures. Animals with fibrotic alterations showed an induction of pancreatic pro-collagen 1 gene expression, and the infiltration of immune cells was accompanied by the expression of the inflammatory mediators MIP-1alpha, IL-1beta, and TGF-beta in 33% (4/12) of the animals. Acinar cell stress was manifested by a significant up-regulation of pancreatitis-associated protein expression (PAP) in smoke-exposed animals (smoke-exposed 6,932 +/- 1,236 vs control 3,608 +/- 305, p < 0.05). Possibly contributing to the morphological damage to the exocrine pancreas, the inhalation of cigarette smoke induced trypsinogen and chymotrypsinogen gene expression and, furthermore, reduced pancreatic enzyme content.

CONCLUSIONS

This study provides experimental evidence of morphological pancreatic damage induced by the inhalation of cigarette smoke, which is likely to be mediated by alterations of acinar cell function.

Nanocluster model of photothermal assay: application for high-sensitive monitoring of nicotine-induced changes in metabolism, apoptosis, and necrosis at a cellular level

This study evaluates the capability of a photothermal (PT) assay to monitor the impact of nicotine on pancreatic cancer cells (AR42J). The specific PT response is closely proportional to nicotine concentrations at concentration range 1 nM to 100 microM, while at high concentrations of nicotine ranging from 1 mM to 50 mM, PT response shows dramatic decrease. According to the theoretical model, the mechanism of the PT assay is associated with metabolic and apoptotic-related shrinking of local cellular absorbing nanoscale zones caused by increased local absorption at low nicotine doses, while high doses of nicotine lead to apoptotic release of absorbing component (cytochrome c) into the intracellular space, and necrotic swelling of organelles, thereby causing a decrease in local absorption. This model is verified with conventional imaging and with Annexin-V Propidium iodide kits. The PT assay, in addition to its high sensitivity (3 orders of magnitude better than conventional assay), shows the potential to distinguish between various functional states of cells that are associated with changes in metabolism, early and late stages of apoptosis, and necrosis. Comparison of PT responses of pancreatic tumor cells AR42J with isolated primary pancreatic acinar cells and HepG2 cells shows a universal nature of PT assay.