Alcohol inhibits cell mitosis in G2-M phase in cell cycle in a human lymphocytes in vitro study

Short-term exposure to ethanol induces transcriptional changes in nontumorigenic breast cells

Breast cancer is a leading cause of cancer-related deaths in women. Many genetic and behavioral risk factors can contribute to the initiation and progression of breast cancer, one being alcohol consumption. Numerous epidemiological studies have established a positive correlation between alcohol consumption and breast cancer; however, the molecular basis for this link remains ill defined. Elucidating ethanol-induced changes to global transcriptional programming in breast cells is important to ultimately understand how alcohol and breast cancer are connected mechanistically. We investigated induced transcriptional changes in response to a short cellular exposure to moderate levels of alcohol. We treated the nontumorigenic breast cell line MCF10A and the tumorigenic breast cell lines MDA-MB-231 and MCF7, with ethanol for 6 h, and then captured the changes to ongoing transcription using 4-thiouridine metabolic labeling followed by deep sequencing. Only the MCF10A cell line exhibited statistically significant changes in newly transcribed RNA in response to ethanol treatment. Further experiments revealed that some ethanol-upregulated genes are sensitive to the dose of alcohol treatment, while others are not. Gene Ontology and biochemical pathway analyses revealed that ethanol-upregulated genes in MCF10A cells are enriched in biological functions that could contribute to cancer development.

Decreased myoblast differentiation in chronic binge alcohol-administered simian immunodeficiency virus-infected male macaques: role of decreased miR-206

Skeletal muscle stem cells play a critical role in regeneration of myofibers. We previously demonstrated that chronic binge alcohol (CBA) markedly attenuates myoblast differentiation potential and myogenic gene expression. Muscle-specific microRNAs (miRs) are implicated in regulation of myogenic genes. The aim of this study was to determine whether myoblasts isolated from asymptomatic CBA-administered simian immunodeficiency virus (SIV)-infected macaques treated with antiretroviral therapy (ART) showed similar impairments and, if so, to elucidate potential underlying mechanisms. Myoblasts were isolated from muscle at 11 mo after SIV infection from CBA/SIV macaques and from time-matched sucrose (SUC)-treated SIV-infected (SUC/SIV) animals and age-matched controls. Myoblast differentiation and myogenic gene expression were significantly decreased in myoblasts from SUC/SIV and CBA/SIV animals compared with controls. SIV and CBA decreased muscle-specific miR-206 in plasma and muscle and SIV decreased miR-206 expression in myoblasts, with no statistically significant changes in other muscle-specific miRs. These findings were associated with a significant increase in histone deacetylase 4 (HDAC4) and decrease in myogenic enhancer factor 2C (MEF2C) expression in CBA/SIV muscle. Transfection with miR-206 inhibitor decreased myotube differentiation, increased expression of HDAC4, and decreased MEF2C, suggesting a critical role of miR-206 in myogenesis. Moreover, HDAC4 was confirmed to be a direct miR-206 target. These results support a mechanistic role for decreased miR-206 in suppression of myoblast differentiation resulting from chronic alcohol and SIV infection. The parallel changes in skeletal muscle and circulating levels of miR-206 warrant studies to establish the possible use of plasma miR-206 as an indicator of impaired muscle function.

Chronic binge alcohol consumption alters myogenic gene expression and reduces in vitro myogenic differentiation potential of myoblasts from rhesus macaques

Chronic alcohol abuse is associated with skeletal muscle myopathy. Previously, we demonstrated that chronic binge alcohol (CBA) consumption by rhesus macaques accentuates skeletal muscle wasting at end-stage of simian immunodeficiency virus (SIV) infection. A proinflammatory, prooxidative milieu and enhanced ubiquitin proteasome activity were identified as possible mechanisms leading to loss of skeletal muscle. The possibility that impaired regenerative capacity, as reflected by the ability of myoblasts derived from satellite cell (SCs) to differentiate into myotubes has not been examined. We hypothesized that the inflammation and oxidative stress in skeletal muscle from CBA animals impair the differentiation capacity of myoblasts to form new myofibers in in vitro assays. We isolated primary myoblasts from the quadriceps femoris of rhesus macaques that were administered CBA or isocaloric sucrose (SUC) for 19 mo. Proliferation and differentiation potential of cultured myoblasts were examined in vitro. Myoblasts from the CBA group had significantly reduced PAX7, MYOD1, MYOG, MYF5, and MEF2C expression. This was associated with decreased myotube formation as evidenced by Jenner-Giemsa staining and myonuclei fusion index. No significant difference in the proliferative ability, cell cycle distribution, or autophagy was detected between myoblasts isolated from CBA and SUC groups. Together, these results reflect marked dysregulation of myoblast myogenic gene expression and myotube formation, which we interpret as evidence of impaired skeletal muscle regenerative capacity in CBA-administered macaques. The contribution of this mechanism to alcoholic myopathy warrants further investigation.

Manipulation of culture conditions for BHK cell growth inhibition by IRF-1 activation

The activation of interferon-regulatory-factor-1 (IRF-1) hasbeen applied to regulate the cell growth of BHK cells. Theconstitutively expressed IRF-1-estrogen receptor fusion protein(IRF-1-hER) activated by the addition to the culture medium ofan estrogen analogue (estradiol), enabled IRF-1 to gain itstranscriptional activator function. By using a dicistronicstabilised self-selecting construct it was possible to controlcell proliferation. With the addition of 100 nM of estradiol at the beginning of the exponential phase, the IRF-1 activationled to a rapid cell growth inhibition. Two days after estradioladdition cell concentration was still maintained but a decreasein cell viability was observed. This cell response isindependent on clone (producer and non-producer) and culturesystem (static and stirred cultures). Specificrecombinant-protein productivity of the producer clone was notsignificantly altered. Control experiments confirmed that IRF-1activation effect was not due to the addition of estradiol per se, estradiol solvent or serum concentration. The extent ofcell growth inhibition is dependent on estradiol concentrationand estradiol addition time, although a decrease in cellviability was always observed. Reducing the time span ofestradiol exposure allowed the decrease in the cell viability tobe controlled and the stationary inhibited phase to be extended:when the time of contact between the cells and estradiol isreduced cell viability increases, archieving values similar tothose obtained if no estradiol is added. During this recoveryphase the cells passed two different phases: first a stationaryphase extension where cell growth was still inhibited, followedby an increase of cell concentration. The IRF-1 system isreversible. This pattern can be repeated for an extended period when estradiol addition and removal are repeated, showing acyclic response. Thus, it is possible to modulate the IRF-1effect by manipulating cycles of addition/removal of estradioland in this way the stationary phase can be maintained.

Alcohol suppresses the granulopoietic response to pulmonary Streptococcus pneumoniae infection with enhancement of STAT3 signaling

Enhanced granulopoietic activity is crucial for host defense against bacterial pneumonia. Alcohol impairs this response. The underlying mechanisms remain obscure. G-CSF produced by infected lung tissue plays a key role in stimulating bone marrow granulopoiesis. This study investigated the effects of alcohol on G-CSF signaling in the regulation of marrow myeloid progenitor cell proliferation in mice with Streptococcus pneumoniae pneumonia. Chronic alcohol consumption plus acute alcohol intoxication suppressed the increase in blood granulocyte counts following intrapulmonary challenge with S. pneumoniae. This suppression was associated with a significant decrease in bone marrow granulopoietic progenitor cell proliferation. Alcohol treatment significantly enhanced STAT3 phosphorylation in bone marrow cells of animals challenged with S. pneumoniae. In vitro experiments showed that G-CSF-induced activation of STAT3-p27(Kip1) pathway in murine myeloid progenitor cell line 32D-G-CSFR cells was markedly enhanced by alcohol exposure. Alcohol dose dependently inhibited G-CSF-stimulated 32D-G-CSFR cell proliferation. This impairment of myeloid progenitor cell proliferation was not attenuated by inhibition of alcohol metabolism through either the alcohol dehydrogenase pathway or the cytochrome P450 system. These data suggest that alcohol enhances G-CSF-associated STAT3-p27(Kip1) signaling, which impairs granulopoietic progenitor cell proliferation by inducing cell cycling arrest and facilitating their terminal differentiation during the granulopoietic response to pulmonary infection.

Alcohol and adult neurogenesis: Roles in neurodegeneration and recovery in chronic alcoholism

The concept of "structural plasticity" has emerged as a potential mechanism in neurodegenerative and psychiatric diseases such as drug abuse, depression, and dementia. Chronic alcoholism is a progressive neurodegenerative disease while the person continues to abuse alcohol, though clinical and imaging studies show that some recovery may occur with abstinence. The neural plasticity observed in chronic alcoholism coupled with conflicting reports on alcohol-induced hippocampal neuropathology make this disease ripe for reconsideration in terms of the phenomenon of adult neurogenesis. This review describes opposing neurogenic processes that occur with alcohol intoxication and abstinence following alcohol dependence and how these opposing events relate to neurodegeneration and recovery from chronic alcoholism.

Ethanol decreases negative cell-cycle-regulating proteins in a head and neck squamous cell carcinoma cell line

Epidemiologic studies have provided evidence of an alcohol-associated increased risk of upper aerodigestive tract cancers. Recently we reported ethanol-induced proliferation in a squamous cell carcinoma of the head and neck (SCCHN) cell line, but the underlying mechanisms are unknown. In order to further clarify these findings, major G0/G1-regulating proteins were investigated in the present study. Synchronized cells of a SCCHN line (JP-PA) and a human immortalized keratinocyte line (HaCaT)-used as a control-were cultured with or without 10(-3) M ethanol for up to 96 h. At distinct time intervals the expression of cyclin D1 and the inhibitors p16, p18, p19 and p21 were determined by Western blot analyses. In both lines ethanol had no influence on the protein expression of cyclin D1. In contrast, distinct downregulations of p21, p18 and p19 were detectable at the protein level. The p16 protein was not expressed in the SCCHN line and was unchanged in the control line after the addition of ethanol. In these in vitro experiments the marked downregulation of important cell-cycle inhibitors may accelerate progression from the G1 to the S phase of the cell cycle. The relevance of our findings to in vivo conditions remains speculative, but the observed mechanisms of significantly reduced expression of cell-cycle inhibitor proteins may be involved in the carcinogenesis of head and neck malignancies.

Alcohol modulates cytokine secretion and synthesis in human fetus: an in vivo and in vitro study

It is well recognized that alcohol passes through the placenta and affects the fetal immune system. The underlying mechanism accounting for immune suppression is not clear. Cytokines are recognized as the principal mediators of a variety of immunologic and pathophysiologic events. The study was designed to examine whether alcohol use during pregnancy affects cytokine synthesis and secretion in the human fetus. Fetal (cord blood) and mother's blood were used for the study. Studies were conducted in vivo and in vitro. For the in vivo study, cytokine levels were measured in cord blood in mothers who drank moderate to heavy (chronic) amounts of alcohol during pregnancy. For the in vitro study, cord blood was obtained from mothers who were drug-free throughout pregnancy. Lymphocytes were isolated and stimulated with lipopolysaccharide (LPS; Escherichia coli, 26:B6). The capacity of lymphocytes to synthesize cytokines was examined in the presence of 20, 50, and 100 mM alcohol. Among the cytokines examined were the tumor necrosis factor (TNF alpha) and interleukins (IL-1 alpha and beta and IL-6). The selection of cytokines was based on their presumptive role in the pathophysiology of alcoholism. Cytokines were measured by using a specific immunoassay. When data obtained from moderate alcohol users were compared with those obtained from nonusers, no significant differences were observed in any of the cytokines examined (p>0.05). In chronic alcohol users, levels for all cytokines increased significantly (p<0.001) in both the fetus and the mother. Among the cytokines, IL-1beta, IL-6, and TNFalpha were the predominant cytokines affected by chronic use of alcohol during pregnancy. The order of stimulation was IL-6, IL-1 beta, TNFalpha, and IL-1 alpha in descending order. In the in vitro study, alcohol blunted LPS stimulation of cytokines, and the alcohol-induced decrease in cytokine synthesis was proportional to the level of alcohol in the media, suggesting a direct effect of alcohol on cytokine synthesis. In general, the blunting effect of alcohol on LPS stimulation was more prominent in the fetus compared with that in mother. We conclude that chronic alcohol use during pregnancy stimulated the fetal cytokine synthesis and secretion, and IL-1beta, IL-6, and TNF alpha were the predominant cytokines affected by alcohol. The in vitro data suggest a direct effect of alcohol on cytokine synthesis.

Osmotic effects of ethanol on lymphocytes

The alterations in the immune system caused by ethanol appear to be a complex combination of direct and indirect effects. The role of ethanol as an osmolyte has previously been studied in this laboratory with rat splenocytes. In the present study the osmotic effects of ethanol were investigated in lymphocytes from human normal subjects and alcohol abusers. Mitogen-stimulated lymphocytes were cultured in vitro with ethanol in hyperosmotic isotonic or iso-osmotic hypotonic conditions. The former conditions mimic the physiological situation where ethanol increases osmolality in an electrolyte-balanced environment. Under these conditions, lymphocyte proliferation was unaffected. Ethanol addition in iso-osmotic hypotonic conditions, where there is electrolyte imbalance, was associated with inhibition of T-lymphocyte proliferation. Hyperosmotic hypertonic solutions in the absence of ethanol also resulted in inhibition of T-lymphocyte proliferation. Electron microscopy and measurement of cell viability and metabolic activity (lactate and ATP levels) indicated that the decreased proliferation associated with NaCl-induced hyperosmotic hypertonic conditions was at least partially attributable to cell death together with, and possibly caused by, detrimental effects on mitochondria. Conversely, decreased T-lymphocyte proliferation in iso-osmotic hypotonic high ethanol solutions, appeared not to be due to changes in cell viability, nor alterations to energy metabolism. It is proposed that ion fluxes involved in the maintenance of cell volume, in particular K ⁺ movement, may be important in facilitating normal lymphocyte proliferation in the presence of ethanol in pathological conditions associated with electrolyte imbalance.