The Immunohistochemical Expression of Epithelial-Mesenchymal Transition Markers in Precancerous Lesions and Cervical Cancer

In the epithelial-mesenchymal transition (EMT) process, cells lose their epithelial phenotype and gain mesenchymal features. This phenomenon was observed in the metastatic phase of neoplastic diseases, e.g., cervical cancer. There are specific markers that are expressed in the EMT. The aim of this study was to determine the localization of and associations between the immunohistochemical (IHC) expression of TWIST, SNAIL, and SLUG proteins in precancerous lesions and cervical cancer. The IHC analysis disclosed higher expressions of EMT markers in precancerous lesions and cervical cancer than in the control group. Moreover, stronger expression of TWIST, SNAIL, and SLUG was observed in cervical intraepithelial neoplasia grade 3 (CIN3) vs. CIN1, CIN3 vs. CIN2, and CIN2 vs. CIN1 cases (p < 0.05). In cervical cancer, IHC reactions demonstrated differences in TWIST, SNAIL, and SLUG expression in grade 1 (G1) vs. grade 2 (G2) (p < 0.0011; p < 0.0017; p < 0.0001, respectively) and in G1 vs. grade 3 (G3) (p < 0.0029; p < 0.0005; p < 0.0001, respectively). The results of our study clearly showed that existing differences in the expression of the tested markers in precancerous vs. cancerous lesions may be utilized in the diagnosis of cervical cancer. Further studies on bigger populations, as well as in comparison with well-known markers, may improve our outcomes.

The Expression of Testin, Ki-67 and p16 in Cervical Cancer Diagnostics

Testin is a protein expressed in normal human tissues, being responsible, with other cytoskeleton proteins, for the proper functioning of cell−cell junction areas and focal adhesion plaques. It takes part in the regulation of actin filament changes during cell spreading and motility. Loss of heterozygosity in the testin-encoding gene results in altered protein expression in many malignancies, as partly described for cervical cancer. The aim of our study was the assessment of the immunohistochemical (IHC) expression of testin in cervical cancer and its analysis in regard to clinical data as well the expression of the Ki-67 antigen and p16 protein. Moreover, testin expression was assessed by Western blot (WB) in commercially available cell lines. The IHC analysis disclosed that the expression of testin inversely correlated with p16 (r = −0.2104, p < 0.0465) and Ki-67 expression (r = −0.2359, p < 0.0278). Moreover, weaker testin expression was observed in cancer cases vs. control ones (p < 0.0113). The WB analysis of testin expression in the cervical cancer cell lines corresponded to the IHC results and showed a weaker expression compared to that in the control cell line. When we compared the expression of testin in cervical cancer cell lines, we found a weaker expression in HPV-negative cell lines. In summary, we found that the intensity of testin expression and the number of positive cells inversely correlated with the expression of Ki-67 (a marker of proliferation) and p16 (a marker of cell cycle dysregulation). This study shows that the combined assessment of testin, Ki-67 and p16 expression may improve cervical cancer diagnostics.

The Role of Periostin in Angiogenesis and Lymphangiogenesis in Tumors

Simple Summary

Cancers are common diseases that affect people of all ages worldwide. For this reason, continuous attempts are being made to improve current therapeutic options. The formation of metastases significantly decreases patient survival. Therefore, understanding the mechanisms that are involved in this process seems to be crucial for effective cancer therapy. Cancer dissemination occurs mainly through blood and lymphatic vessels. As a result, many scientists have conducted a number of studies on the formation of new vessels. Many studies have shown that proangiogenic factors and the extracellular matrix protein, i.e., periostin, may be important in tumor angio- and lymphangiogenesis, thus contributing to metastasis formation and worsening of the prognosis.

Abstract

Periostin (POSTN) is a protein that is part of the extracellular matrix (ECM) and which significantly affects the control of intracellular signaling pathways (PI3K-AKT, FAK) through binding integrin receptors (αvβ3, αvβ5, α6β4). In addition, increased POSTN expression enhances the expression of VEGF family growth factors and promotes Erk phosphorylation. As a result, this glycoprotein controls the Erk/VEGF pathway. Therefore, it plays a crucial role in the formation of new blood and lymphatic vessels, which may be significant in the process of metastasis. Moreover, POSTN is involved in the proliferation, progression, migration and epithelial-mesenchymal transition (EMT) of tumor cells. Its increased expression has been detected in many cancers, including breast cancer, ovarian cancer, non-small cell lung carcinoma and glioblastoma. Many studies have shown that this protein may be an independent prognostic and predictive factor in many cancers, which may influence the choice of optimal therapy.

Expression of Zyxin in Non-Small Cell Lung Cancer-A Preliminary Study

Background: The potential involvement of zyxin (ZYX) in carcinogenesis has been investigated in many cancer types. However, there are a limited number of studies on the role of ZYX in the progression of non-small cell lung cancer (NSCLC). Since lung cancer is one of the most frequently diagnosed carcinomas, the aim of our study was to determine the localization and expression levels of ZYX in NSCLC and to correlate the results with the clinicopathological data. Materials and Methods: The expression of ZYX was assessed in NSCLC cases and in cell lines representing this tumor type. Levels of ZYX were determined in the clinical material using immunohistochemistry (IHC) and Western Blot. Real-time PCR was used to assess ZYX mRNA levels. The expression of ZYX was also checked in NSCLC cell lines using real-time PCR, Western Blot, and immunofluorescence/immunocytochemistry. Results: The results showed lower levels of ZYX in NSCLC cells compared with control tissues. This trend was observed at the protein and mRNA levels. The assays on the NSCLC model also demonstrated lower levels of ZYX in cancer cells compared with control cells. Conclusions: The decreased expression of ZYX in NSCLC may indicate a suppressor role of this protein in NSCLC.

Irisin Association with Ki-67, MCM3 and MT-I/II in Squamous Cell Carcinomas of the Larynx

Background: Current studies indicate irisin role in carcinogenesis. The aim of the study was to investigate the expression of irisin in LSCCs and to determine its association with clinicopathological factors, as well as recognized markers of proliferation, i.e., Ki-67 and MCM3,5,7 and MT-I/II proteins. Material and methods: The research material consisted of 140 cases of LSCCs, 57 cases of laryngeal papillomas (BLs) and 14 controls (benign hypertrophic changes). Tissue microarrays were used to perform IHC. Western blot and immunofluorescence were performed in laryngeal cancer cell lines and normal keratinocytes. Results: Irisin expression levels were significantly increased in LSCC compared to BLs (p < 0.0001) and controls (p = 0.001). We noted a positive moderate and weak correlation between irisin and Ki-67, MCM3 and MT-I/II. We observed an elevated level of irisin expression with increasing tumor size (T1–2 vs. T3–4; p = 0.0348). The levels of irisin were higher in N0 than in N1 and N2–3 (p = 0.0031 and p = 0.0457, respectively). Our in vitro study revealed a higher level of irisin in Larynx Epidermoid Carcinoma 2 (HEp-2) cells compared to the control Normal Human Keratinocyte (HaCat) cell line. Conclusions: Increased irisin expression levels in LSCC and its correlation with clinicopathological and proliferation factors may indicate the potential role of irisin as a biomarker in the diagnostic process of LSCC.

Comparison of TMA Technique and Routine Whole Slide Analysis in Evaluation of Proliferative Markers Expression in Laryngeal Squamous Cell Cancer

BACKGROUND/AIM

Comparison of the expression of Ki-67, MCM3, 5, 7 and MTI/II proteins using immunohistochemistry (IHC) on whole section (WS) and tissue microarray (TMA) of laryngeal squamous cell carcinoma (LSCC) samples.

MATERIALS AND METHODS

A total of 51 archival paraffin blocks of LSCC were used. TMAs were prepared from 1.5 mm core punches. IHC reactions were performed using antibodies against Ki-67, minichromosome maintenance proteins (MCM3, 5, 7) and metallothionein (MTI/II).

RESULTS

Spearman rank correlation test revealed moderate positive correlation in the case of Ki-67: WS vs. TMA (r=0.38, p=0.07) and strong positive correlation in regard to the rest of tested markers: MCM3, WS vs. TMA (r=0.49, p=0.0004); MCM5, WS vs. TMA (r=0.61, p<0.0001); MCM7, WS vs. TMA (r=0.59, p<0.0001); MTI/II, WS vs. TMA (r=0.66, p<0.0001). Mann Whitney U-test showed no significant differences in the case of Ki-67 and MCM5. Moreover, Bland-Altman test showed a low level of bias in regard to Ki-67, WS vs. TMA and MCM5, WS vs. TMA.

CONCLUSION

TMA may be an effective and reliable method of assessment of Ki-67 and MCM5 expression in LSCC.

The Role of Zyxin in Carcinogenesis

Zyxin (ZYX) is a LIM domain protein whose presence has been detected in the cytoplasm and nucleus. ZYX can translocate between these two compartments and therefore, can take part in the regulation of various cellular processes. VASP and α-actinin are examples of proteins that interact with ZYX. As ZYX is present in focal adhesions (FAs), an immense part of research is focused on the role of this protein in the organisation and function of the cytoskeleton. Other studies aim to explain the impact of zyxin on other intracellular processes. Zyxin has been shown to take part in apoptosis, as well as in wound healing. Additionally, zyxin contribution to cancer development is gaining growing interest. This paper aims to systematise the knowledge on zyxin and its role in carcinogenesis.

Influence of Angiotensin II on cell viability and apoptosis in rat renal proximal tubular epithelial cells in in vitro studies

Introduction:

Angiotensin II (Ang II) is multifunctional peptide that plays an important role in blood pressure regulation and maintenance electrolyte homeostasis. It shows biological effects by activating two main receptors: AT₁ and AT₂. The aim of the present work was to investigate the effect of Ang II on NRK-52E cells in in vitro studies. Furthermore, an attempt was made to determine the effectiveness of the AT₁ and AT₂ receptor blocker activity (respectively, losartan and PD123319).

Methods:

The study was carried out using adherent NRK-52E cell line. Immunofluorescence and Western Blot method were used to confirm the presence of AT₁ and AT₂ receptors in the cells. The SRB and MTT tests showed decrease in the viability of NRK-52E cells incubated with Ang II in comparison to the control (without Ang II).

Results:

The blockade of the AT₁ receptor caused an increase in cell viability in comparison to cells incubated with Ang II only. The blockade of AT₂ receptor also triggered statistically significant increase in cell viability in comparison with cells only exposed to Ang II. Combined administration of blockers for both receptors (losartan and PD123319) decreased Ang II cytotoxicity against NRK-52E cell line. The apoptosis was only observed in cells incubated with Ang II in comparison with control cells. However, simultaneous use of both blockers caused statistically significant decrease in apoptosis.

Conclusions:

The result of our study indicates that Ang II causes damaging effect on NRK-52E cells by directing them to programmed cell death. It seems that not only does the AT₂ receptor itself play an important role in the induction of apoptosis, but also its interaction with AT₁ receptor does as well.

Effect of Physical Training on the Levels of Sex Hormones and the Expression of Their Receptors in Rats With Induced Mammary Cancer in Secondary Prevention Model - Preliminary Study

BACKGROUND/AIM

Breast cancer is the most common malignant tumor among women worldwide. In previous work, we presented results of physical activity in primary prevention in a model of induced mammary gland cancer. In the present study, we assessed the influence of physical activity on sex hormone levels (estradiol and progesterone) and the expression of their receptors (ER, PR), as well as the level of apoptosis of tumor cells in secondary prevention.

MATERIALS AND METHODS

Fifty 1-month-old female Sprague-Dawley rats received intraperitoneal injection of 180 mg/kg body weight of N-methyl-N-nitrosourea (MNU) for tumor induction. Three months after the administration of MNU, rats were divided into four groups: low-intensity, moderate-intensity, and high-intensity physical training groups (combined as PT) and a sedentary control (SC) group. Physical training was conducted 5 days per week with a three-position treadmill according to a precisely described protocol. The entire training was completed by 32 rats from which tissue and blood were collected for further analysis. Immunohistochemistry for ER and PR expression, terminal deoxynucleotidyl transferase dUTP nick-end labeling method for detection of apoptosis, and enzyme-linked fluorescent assay for detection of plasma hormone levels (estradiol and progesterone) were performed. Statistical analysis used p<0.05 as the significance level.

RESULTS

Significantly stronger expression of ER and PR was found in the SC in comparison to the PT group (p=0.035 and p=0.036, respectively). No statistically significant differences were found in estradiol or progesterone concentrations between SC and PT groups. Apoptosis was non-significantly increased in the PT group in comparison with the SC group. Stronger apoptosis in the PT group correlated positively with the level of training intensity (r=0.35, p=0.05).

CONCLUSION

Physical training may reduce ER and PR expression in breast cancer cells, and reduce cell sensitivity to pro-proliferative and anti-apoptotic effects of estrogens, ultimately leading to apoptosis.

Role of PD-L1 Expression in Non-Small Cell Lung Cancer and Their Prognostic Significance according to Clinicopathological Factors and Diagnostic Markers

Background: The latest immunotherapy, used in the treatment of non-small cell lung cancer (NSCLC), uses monoclonal antibodies directed against programmed death ligand 1 (PD-L1) to inhibit its interaction with the PD-1 receptor. Elevated levels of PD-L1 expression were observed on NSCLC cells. The association between PD-L1 expression and clinicopathological features is still unclear. Therefore, we examined this relationship and also compare PD-L1 expression levels with Ki-67, p63 and TTF-1. Methods: 866 samples of NSCLCs were used to prepare tissue microarrays (TMAs) on which immunohistochemical (IHC) reactions were performed. Changes in the level of CD274 (PD-L1) gene expression in 62 NSCLC tumors were tested in relation to 14 normal lung tissues by real-time PCR reactions (RT-PCR). Results: PD-L1 expression was observed in 32.6% of NSCLCs. PD-L1 expression was increased in higher malignancy grades (G) (p < 0.0001) and in higher lymph node status (pN) (p = 0.0428). The patients with low PD-L1 expression had longer overall survival compared to the group with high expression (p = 0.0332) in adenocarcinoma (AC) only. Conclusions: PD-L1 expression seems to be associated with increased tumor proliferation and aggressiveness as well as shorter patient survival in NSCLC, predominantly in the AC group.

Prolactin-induced protein (PIP)-characterization and role in breast cancer progression

Prolactin-induced protein (PIP) is a small secreted glycoprotein carrying several N-linked carbohydrate chains. The expression of PIP is generally restricted to cells with apocrine properties. It was found in apocrine glands of the axilla, vulva, eyelid, ear canal, and seminal vesicle. Being a secretory protein, PIP is present in seminal plasma, saliva, lacrimal fluid, tears, sweat gland secretion. Little is known about the biological role of PIP. It binds to numerous proteins, however, in most cases the biological role of such interactions is poorly understood. A notable exception is its binding to CD4 receptors present on the surface of T lymphocytes, macrophages, and spermatozoa. The available data suggest that PIP can have immunomodulatory functions and plays an important role in cell-mediate adoptive immunity. PIP binds to bacteria from several genera, which suggests that this glycoprotein may participate also in innate immunity and protection of hosts against microbial infections. Increased levels of PIP were found in several types of human cancer (prostate, sweat and salivary gland cancers). It is especially common in breast cancer, however, data on the expression of PIP in normal and cancerous breast cancer tissues are to some degree conflicting. In early studies, it was shown that PIP is absent or its expression is very low in normal breast epithelium, whereas in breast cancers PIP is frequently expressed and present in large amounts. On the other hand, later study showed that expression of PIP is lower in advanced apocrine carcinomas and invasive carcinomas than in, respectively, in situ carcinomas and adjacent normal tissue. The most recent study revealed that PIP gene expression decreased gradually along with higher stage and grade of breast cancer. In agreement with these data, it was shown that that low levels or the lack of PIP expression are associated with a worse response of breast cancer cells to chemotherapy. It was proposed that PIP plays important role in the development and progression of breast cancer. However, its role in these processes is both unclear and controversial. In this review, the role of PIP in both physiological processes and carcinogenesis is discussed.

Effects of massage on the expression of proangiogenic markers in rat skin

INTRODUCTION

Massage is a physiotherapeutic treatment, commonly used in both therapy and restoration of normal body functions. The aim of this work was to determine the effects of skin massage on stimulating the expression of angiogenesis-initiating factors, i.e. VEGF-A, FGF-2 (bFGF) and CD34 and on skin regeneration processes.

MATERIAL AND METHODS

The study was conducted on 48 Buffalo strain rats, randomly divided into two groups. In the first group (M, the massaged group), massage was applied five times a week for 7 weeks. In the second study group (C, the control group), the massage was omitted. Massage consisted of spiral movements at the plantar surface of skin for 5 min on each rear extremity. The gene expression of proangiogenic factors, including VEGF-A, FGF-2, CD34 at the mRNA level was determined using real-time PCR. Immunohistochemistry was performed on paraffin sections of rat skin to determine VEGF-A, FGF-2 CD34 and Ki-67expression.

RESULTS

An increase in mRNA expression in the skin of the rat's rear extremity for VEGF-A and FGF-2 in the first week of the experiment was shown in the M group compared with the control rats. The upregulation of CD34 mRNA expression was also observed in the M group. We observed positive correlations between VEGF-A mRNA expression and the expression of mRNA for FGF-2 and CD34, as well as correlation between the expression of mRNA for FGF-2 and CD34. The immunohistochemical expression of VEGF-A, FGF-2 and CD34 was at a much lower level in the skin of control rats relative to the skin of massaged animals. Moreover, significantly higher immunoreactivity was shown for nuclear protein Ki-67 in epidermal cells in the M group compared with the C group.

CONCLUSIONS

Rat skin massage increased the expression of the main angiogenesis-stimulating factors and the proliferative activity of epidermal cells, which can stimulate skin regeneration and tissue repairing processes.

The Impact of Exercise Training on Breast Cancer

BACKGROUND/AIM

Physical exercise is increasingly considered by many authors to be a factor reducing the risk of cancer development and premature cancer-related death. Data indicate higher cure rates and longer times of survival in cancer patients who regularly exercise.

MATERIALS AND METHODS

A total of 50 female Sprague-Dawley rats were used in the experiment. Animals at 1 month of age were intraperitoneally injected with N-methyl-N-nitrosourea. Three months following drug administration, rats underwent supervised physical training. The animals were divided into four groups: control untrained group and 3 groups trained with different intensities - i.e. low, moderate and high. Routine histopathological examination of tumors was performed and mitotic activity was assessed by immunohistochemical expression of the Ki-67 antigen.

RESULTS

Ki-67 antigen expression was observed in all analyzed tumors. The increase in Ki-67 antigen expression correlated positively with the increase in training intensity.

CONCLUSION

It can be assumed that low-intensity physical training is safe for patients with breast cancer. However, moderate- and high-intensity training may induce tumor cell proliferation worsening patients' prognosis.

SATB1 Level Correlates with Ki-67 Expression and Is a Positive Prognostic Factor in Non-small Cell Lung Carcinoma

BACKGROUND

Non-small cell lung carcinomas (NSCLCs), mainly adenocarcinoma (AC) and squamous cell carcinoma (LSCC), account for about 80% of all lung cancer cases. One of the proteins involved in NSCLC progression may be special AT-rich binding protein 1 (SATB1), a potent transcriptional regulator, able to control the expression of whole sets of genes simultaneously. SATB1 has been found to be associated with aggressive phenotype and poor prognosis in numerous malignancies, including breast, colon, ovary and prostate cancer. However, its role in NSCLC is still not fully understood. The aim of this study was to investigate the expression of SATB1 protein and mRNA in NSCLC and non-malignant lung tissue (NMLT) samples, as well as to determine possible relationships of SATB1 expression with both the expression of Ki-67 and the clinicopathological data of the patients.

MATERIALS AND METHODS

The study was performed on 277 NSCLC (158 AC, 119 LSCC) and 20 NMLT samples.

RESULTS

We observed increased SATB1 immunoreactivity in NSCLC when compared to NMLT, and in LSCC when compared to AC cases. We also noted that an elevated SATB1 immunoreactivity was associated with a poor degree of AC differentiation, whereas in LSCC, an inverse relationship was observed. Our analyses revealed that the expression of SATB1 positively correlated with Ki-67 index in NSCLC and LSCC, but not in AC cases. Finally, we found that high SATB1 expression was associated with a better overall survival of patients with NSCLC.

CONCLUSION

SATB1 plays diverse roles in different NSCLC subtypes, and its expression may have a prognostic significance for patients with these tumours.

Correlation of Pyruvate Kinase M2 Expression with Clinicopathological Data in Ovarian Cancer

BACKGROUND/AIM

It has been shown in many studies that expression of pyruvate kinase (PK) enzyme plays a key role during cellular metabolism. There is evidence that cancer cells manifesting very dynamic proliferation may control their division in various mechanisms, i.a. by expression of PKM2 isoform. The exact role of PKM2 in ovarian cancer (OC) cells and cancer associated fibroblasts (CAFs) have not been elucidated.

MATERIALS AND METHODS

The present study was focused on analysis of PKM2 expression in cancer cells and CAFs in 97 OC cases, mostly of serous histological type. Moreover, relationships between expression of PKM2 and proliferation (Ki-67; MCM-2, -3, -7; cyclin D1), vascular (CD31, D2-40) and mesenchymal (Vim and αSMA) markers as well as receptors (ER, PR, HER2, EGFR) were examined. All observations were evaluated in regard to available clinicopathological data.

RESULTS

The expression of PKM2 was disclosed only in cytoplasm of OC cells. No statistically significant correlation between PKM2 and tested markers was found. In regard to available clinicopathological data only an increasing trend of PKM2 expression with increasing grade of histological malignancy G was found (p=0.07).

CONCLUSION

Due to achieved results concerning expression of PKM2 there is a lack of evidence for its diagnostic and prognostic usage in OC.

Correlation Between Expression of Twist and Podoplanin in Ductal Breast Carcinoma

BACKGROUND/AIM

As a result of activation of transcription factors engaged in epithelial-mesenchymal transition (EMT), such as Twist, inhibition of epithelial markers and an increased expression of mesenchymal markers are observed. One of the specific markers of cancer-associated fibroblasts is podoplanin (PDPN) - a mucin-type membrane glycoprotein. The aim of this work was to study the localisation and intensity of expression of Twist and PDPN on the mRNA and protein level in cases of invasive ductal breast carcinoma (IDC), and its association with patients' clinico-pathological data.

MATERIALS AND METHODS

The study included archival material in a form of 80 paraffin IDC blocks and 11 IDC fragments frozen in liquid nitrogen. Immunohistochemical expression of Twist and PDPN was evaluated using light microscope and semiquantitative scale for evaluation of nuclear expression or immunoreactive scale (IRS) for evaluation of cytoplasmic expression. Material was isolated from frozen IDC fragments using laser micro-dissection (from cancer and stromal cells, separately) and was used to perform real-time PCR.

RESULTS

Twist expression was higher in stromal cells in comparison to cancer cells. Analysis of patients' survival rate showed, that higher expression of Twist in cancer cells was associated with shorter overall survival time and shorter event-free survival time. The expression of PDPN was also higher in stromal cells in comparison with cancer cells. In addition, positive correlation was observed between expression of Twist and PDPN in stromal cells of IDC (r=0.267; p<0.05).

CONCLUSION

The relationship between the higher expression of Twist in both cancer and stromal cells and shorter patients' survival indicates Twist as a potential useful prognostic marker in IDC. Positive correlation of Twist and PDPN expression may indicate the role of PDPN in EMT in IDC.

Carvedilol Inhibits Matrix Metalloproteinase-2 Activation in Experimental Autoimmune Myocarditis: Possibilities of Cardioprotective Application

AIMS

Acute myocarditis is a potentially lethal inflammatory heart disease that frequently precedes the development of dilated cardiomyopathy and subsequent heart failure. At present, there is no effective standardized therapy for acute myocarditis, besides the optimal care of heart failure and arrhythmias in accordance with evidence-based guidelines and specific etiology-driven therapy for infectious myocarditis. Carvedilol has been shown to be cardioprotective by reducing cardiac pro-inflammatory cytokines present in oxidative stress in certain heart diseases. However, effects of carvedilol administration in acute myocarditis with its impact on matrix metalloproteinases' (MMPs) activation have not been elucidated.

METHODS AND RESULTS

Carvedilol in 3 doses (2, 10, and 30 mg/kg) was given daily to 3 study groups of rats (n = 8) with experimental autoimmune myocarditis by gastric gavage for 3 weeks. In comparison to untreated rats (n = 8) with induced myocarditis, carvedilol significantly prevented the left ventricle enlargement and/or systolic dysfunction depending on the dose in study groups. Performed zymography showed enhanced MMP-2 activity in untreated rats, while carvedilol administration reduced alterations. This was accompanied by prevention of troponin I release and myofilaments degradation in cardiac muscle tissue. Additionally, severe inflammatory cell infiltration was detected in the nontreated group. Carvedilol in all doses tested, had no impact on severity of inflammation. The severity of inflammation did not differ between study groups and in relation to the untreated group.

CONCLUSIONS

The protective effects of carvedilol on heart function observed in the acute phase of experimental autoimmune myocarditis seem to be associated with its ability to decrease MMP-2 activity and subsequently prevent degradation of myofilaments and release of troponin I while not related to suppression of inflammation.

Impact of Physical Training on Sex Hormones and Their Receptors During N-Methyl-N-nitrosourea-induced Carcinogenesis in Rats

BACKGROUND/AIM

The risk of breast cancer is related to duration of exposure to sex hormones, especially estrogen. The aim of this study was to assess the impact of physical training (PT) on estrogen and progesterone levels and expression of their receptors during carcinogenesis induced by N-methyl-N-nitrosourea (MNU) in rats.

MATERIALS AND METHODS

Fifty female Sprague-Dawley rats were intraperitoneally administered MNU and divided into four groups: low-, moderate-, and high-intensity PT, and no PT (control). Plasma levels of sex hormones and tissue expression of their receptors were quantified and statistically analyzed.

RESULTS

In the group of rats subjected to PT, a significantly higher progesterone level was observed. The highest progesterone level was noted in the low-intensity PT group. An increase in apoptosis of MNU-induced tumor cells was also demonstrated in the PT groups.

CONCLUSION

PT stimulates apoptosis of tumor cells without an increase in their proliferative activity. The increase in apoptosis of tumor cells correlates positively with the progesterone level.

Expression of Cell Cycle-related Proteins p16, p27 and Ki-67 Proliferating Marker in Laryngeal Squamous Cell Carcinomas and in Laryngeal Papillomas

BACKGROUND

The deregulation of the cell cycle is crucial for the processes of carcinogenesis and tumor progression. The cell cycle is under the control of cyclin-dependent kinases (CDKs) and their inhibitors (CDKIs). Proteins p16 and p27 are CDKIs, and their altered expression has been noticed in many types of cancers. The aim of this study has been to compare the expression levels of these proteins in laryngeal papillomas and carcinomas in order to confirm their predictive value in cancer development.

MATERIALS AND METHODS

Eighty-three cases of laryngeal lesions were analyzed: cancers (51) and papillomas (32). Immunohistochemical (IHC) reactions were performed in order to detect the expression levels of p16, p27 and Ki-67. Immunofluorescence (IF) and western blot were performed on HEp-2 cell line.

RESULTS

The expression of p16 and p27 was decreased in cancer cells in comparison to papillomas. Additionally, we observed cytoplasmic expression of p16 in cancers and lack of such expression in papillomas. The same pattern of expression of p16 was also detected by IF and western blot analysis in HEp-2 cell line. The expression of Ki-67 protein revealed no significant differences in the case of papilloma compared with cancer, however a significant correlation between tumor grade and the nuclear expression of Ki-67 was observed.

CONCLUSION

There is a necessity in finding biomarkers, which would predict the risk level of malignant transformation. Our study has confirmed that altered expressions of the p16 and p27 proteins might be useful biomarkers in the progression of laryngeal squamous cell carcinomas (LSCC).

Expression of metallothionein 3 in ductal breast cancer

Metallothionein 3 (MT-3) has the ability to regulate the growth of nerve cells, but the significance of MT-3 expression outside the central nervous system and its participation in carcinogenesis have not yet been clarified. The aim of our study was to investigate the expression of MT-3 in ductal breast cancer and to determine its relationship with well-defined clinicopathological factors in this type of tumor. The study was conducted on 134 cases of invasive ductal breast carcinoma (IDC), 42 samples of non-malignant breast tissue (NMBT), and 26 cases of mastopathy. Moreover, selected breast cancer cell lines (MCF-7, SKBR-3, MDA-MB-231, BO2) and normal human breast epithelial cells (hTERT-HME1) were used. The expression of MT-3 was examined on the protein level using immunohistochemistry and on the mRNA level using real-time PCR. It was shown that the MT-3 protein in cells of IDC and mastopathy appeared in the cytoplasm as well as in the cell nuclei. Both the cytoplasmic and nuclear expression of MT-3 was significantly lower in IDC than in the mastopathies (p<0.0001 and p<0.001). However, no significant correlation was demonstrated between the level of MT-3 protein and the studied clinicopathological factors. The mRNA expression of MT-3 in IDC was also lower than in non‑malignant breast tissue (p<0.0001). Furthermore, in the cases of IDC with lymph node metastasis, the level of MT-3 mRNA was significantly lower than in the cases without metastasis (p=0.0199). The expression of MT-3 mRNA in breast cancer cell lines was significantly lower than in the normal human breast epithelial cell line (p<0.001). These results suggest that MT-3 may play a role in the malignant transformation of breast epithelial cells and in tumor progression.

Expression of Cell Cycle-Related Proteins p16, p27, p53 and Ki-67 in HPV-positive and -negative Samples of Papillomas of the Upper Respiratory Tract

BACKGROUND

The role of human papillomavirus (HPV) infection as an etiological factor of respiratory tract papillomas has been described in numerous studies, however its role in malignant transformation has not been clearly defined. Depending on their oncogenic potential they have been classified as low- and high-risk HPVs. We analyzed the expression of four cell cycle-related proteins in order to understand the processes leading to malignant transformation.

MATERIALS AND METHODS

Fifty-six cases of pharyngeal and laryngeal papillomas were analyzed. Nested multiplex polymerase chain reactions to detect the presence of the HPV types, as well as immunohistochemical reactions were performed for the detection of cell cycle-related proteins p16, p27, p53 and Ki-67.

RESULTS

The presence of HPVs 6/11 and 16 was confirmed in 10/56 cases. The expression of all analyzed cell cycle-related proteins was increased in HPV-infected papillomas.

CONCLUSION

HPV infection of the upper respiratory tract may influence the expression of cell cycle-related proteins, that could indicate its possible role in the process of malignant transformation.

Prolactin-induced protein as a potential therapy response marker of adjuvant chemotherapy in breast cancer patients

Many studies are dedicated to exploring the molecular mechanisms of chemotherapy-resistance in breast cancer (BC). Some of them are focused on searching for candidate genes responsible for this process. The aim of this study was typing the candidate genes associated with the response to standard chemotherapy in the case of invasive ductal carcinoma. Frozen material from 28 biopsies obtained from IDC patients with different responses to chemotherapy were examined using gene expression microarray, Real-Time PCR (RT-PCR) and Western blot (WB). Based on the microarray results, further analysis of candidate gene expression was evaluated in 120 IDC cases by RT-PCR and in 224 IDC cases by immunohistochemistry (IHC). The results were correlated with clinical outcome and molecular subtype of the BC. Gene expression microarray revealed Prolactin-Induced Peptide (PIP) as a single gene differentially expressed in BC therapy responder or non-responder patients (p <0.05). The level of PIP expression was significantly higher in the BC therapy responder group than in the non-responder group at mRNA (p=0.0092) and protein level (p=0.0256). Expression of PIP mRNA was the highest in estrogen receptor positive (ER+) BC cases (p=0.0254) and it was the lowest in triple negative breast cancer (TNBC) (p=0.0336). Higher PIP mRNA expression was characterized by significantly longer disease free survival (DFS, p=0.0093), as well as metastasis free survival (MFS, p=0.0144). Additionally, PIP mRNA and PIP protein expression levels were significantly higher in luminal A than in other molecular subtypes and TNBC. Moreover significantly higher PIP expression was observed in G1, G2 vs. G3 cases (p=0.0027 and p=0.0013, respectively). Microarray analysis characterized PIP gene as a candidate for BC standard chemotherapy response marker. Analysis of clinical data suggests that PIP may be a good prognostic and predictive marker in IDC patients. Higher levels of PIP were related to longer DFS and MFS but not with OS.

Expression of Metallothionein and Vascular Endothelial Growth Factor Isoforms in Breast Cancer Cells

BACKGROUND

Metallothioneins (MTs) are low-molecular-weight and cysteine-rich proteins that bind heavy metal ions and oxygen-free radicals. MTs are commonly expressed in various tissues of mammals and are involved in regulation of cell proliferation and differentiation, and may be engaged in angiogenesis. Expression of MTs has been studied in many cancer types, especially breast cancer. The research results indicate that MTs may play important, although not yet fully known, roles in cancer angiogenesis. The aim of this study was to analyze the level of gene expression of selected MT isoforms induced with zinc ions in correlation with vascular endothelial growth factor (VEGF) isoforms in in vitro models of breast cancer.

MATERIALS AND METHODS

The studies were carried out in three breast cancer cell lines (MCF-7, SK-BR-3, MDA-MB-231). An epithelial cell line derived from normal breast tissue (Me16c) was used as a control. The levels of expression of selected MT isoforms and selected genes involved in angiogenesis were studied with real-time PCR.

RESULTS

Expression of different MT isoforms was induced by zinc ions to differing degrees in individual breast cancer cell lines. An increase in the expression of some MT isoforms was associated with a slight increase in the level of expression of VEGFA.

CONCLUSION

The research results may indicate certain correlation between an increased expression of selected MT isoforms and a pro-angiogenic factor VEGF in specific types of breast cancer cells.

Metallothioneins in Normal and Cancer Cells

Metallothioneins (MTs) are low molecular weight proteins, which are present in almost all types of organisms. In mammals, four main MT isoforms designated from MT-1 to MT-4 were identified. Their biological role, according to their characteristic structure, was shown to be mostly associated with cellular metabolism of metal ions, especially zinc. Moreover, the available evidence suggests broad regulatory properties of MTs in the control of cell senescence and various pathological processes including neurodegeneration, cardiovascular pathology, metabolic disorders, and various malignancies. This extensive review provides general in formation on the structure of MT family members and the cellular functions of MT-1, MT-2, and MT-4 isoforms as well as insights into divergent biological roles of MT-3. Due to the involvement of MT molecules in various processes related to carcinogenesis, an organ-specific presentation of current data concerning their potential impact on the progression of various tumors is given. The regulatory role of MT family members in the function of the immune system is also discussed in depth.

Plasminogen Activation System in Rectal Adenocarcinoma

BACKGROUND

The purpose of the present study was to determine the extent of expression of proteins that are the elements of the plasminogen activation system, i.e. urokinase plasminogen activator (uPA), receptor of uPA (uPAR), plasminogen activating inhibitor-1 (PAI-1) and tissue plasminogen activator (tPA) in the primary site of rectal adenocarcinoma, as well as in lymph node metastases, and their correlation with clinical and pathological data.

MATERIALS AND METHODS

The study material consisted of archival paraffin blocks from 108 patients with confirmed oncological diagnosis, treated in 2002 and 2003 in the Lower Silesian Oncology Centre in Wroclaw. This material was used for immunohistochemical reactions with antibodies against uPA, uPAR, PAI-1 and tPA. The extent of expression was evaluated semi-quantitatively based on the immunoreactive score according to Remmele and Stegner. The obtained results were correlated with clinical and pathological data: stage of the disease (modified Dukes' classification of Astler and Coller), grade of histological malignancy, event-free survival and overall survival.

RESULTS

It was found that cytoplasmic expression of uPA, uPAR, PAI-1 and tPA was higher in cells of tumor and metastases of perienteric lymph nodes in comparison to normal rectal tissues. Positive correlation was shown between expression of PAI-1 and tPA, uPA and uPAR, as well uPA and PAI-1 (r=0.70, r=0.77 and r=0.34, respectively; p<0.05 for all). Additionally, in patients with low and moderate expression of uPA and uPAR, the overall survival rate was higher in comparison to patients with high expression of the studied markers.

CONCLUSION

The intensity of expression of uPA and uPAR might be a prognostic factor of survival time for patients with primary rectal adenocarcinomas.

Increased skeletal muscle expression of VEGF induced by massage and exercise

INTRODUCTION

Numerous investigations have been carried out to describe the role of massage in preparing for and restoring efficiency after physical exercise. Furthermore, vascular endothelial growth factor (VEGF) enhances blood vessel growth, and in effect contributes to the regeneration of tissues. Since its expression in active skeletal muscles has not been yet determined, the aim of this study was to investigate whether muscle massage performed before and during running exercise affects the expression of VEGF-A in muscles.

MATERIAL AND METHODS

The study was carried out on 75 adult Buffalo rats subjected to running exercise training for 10 weeks. Rats were massaged prior (group PM) or during exercise (group M) or were not massaged (group C). The massage consisted of spiral movements along the plantar surface of flexor digitorum brevis muscle. After 1, 3, 5, 7 and 10 week of training, five rats from every group were anesthetized and immunohistochemistry, Western blot, and PCR analyses were performed on obtained muscle tissue to determine VEGF-A expression.

RESULTS

After the first week of training, a significant increase of VEGF-A gene expression analyzed by qPCR in muscle tissue was observed in the PM group, whereas in the third week, the predominant growth of studied marker was seen in the M group. Increased VEGF-A expression on the protein level was observed in both massaged groups following the first week. A moderate positive correlation was found between the expression of the VEGF-A gene and protein in all experimental groups (r = 0.389).

CONCLUSION

Short-term repeated massage may contribute to processes of creation of new and development of already existing vascular networks in the skeletal muscle tissue during increased exercise.

Metallothioneins in the lung cancer

Metallothioneins (MTs) are low weight proteins involved in several key cellular processes such as metal ions homeostasis, detoxification and scavenging of free radicals. Four groups of MTs are distinguished: MT-1, MT-2, MT-3 and MT-4. Regardless of the type, MTs are characterized by high content of cysteine, responsible for their biological properties such as binding of relevant zinc and copper ions, as well as toxic ions such as lead and cadmium. MTs were additionally shown to protect cells against oxidative stress damage and participate in differentiation, proliferation and/or apoptosis of normal and cancer cells. Many studies of different neoplasms showed association of elevated MTs levels with occurrence of chemo- and radiotherapy resistance and poor patients' outcome. In this review, we summarize and discuss the potential mechanism of action of metallotioneins in lung physiology and pathology.

Expression of the MT1 melatonin receptor in ovarian cancer cells

Ovarian cancer (OC) is the leading cause of death among women with genital tract disorders. Melatonin exhibits oncostatic properties which it may effect through binding to its membrane receptor, MT1. The aim of this study was to determine the expression of MT1 in OC cells and to correlate this with clinical and pathological data. Immunohistochemistry was performed on 84 cases of OC. Normal ovarian epithelial (IOSE 364) and OC (SK-OV-3, OVCAR-3) cell lines were used to examine the MT1 expression at protein level using the western blot and immunofluorescence technique. The expression of MT1 was observed as cytoplasmic-membrane (MT1_CM) and membrane (MT1_M) reactions. A positive correlation between MT1_CM and MT1_M was found in all the studied cases. There were no significant differences between the expression of MT1_CM, MT1_M, and histological type, staging, grading, presence of residual disease, or overall survival time. Immunofluorescence showed both MT1_M and MT1_CM expression in all the tested cell lines. Western blot illustrated the highest protein level of MT1 in IOSE 364 and the lowest in the OVCAR-3. The results indicate the limited prognostic significance of MT1 in OC cells.

LAM cells biology and lymphangioleiomyomatosis

Progressive lung tissue destruction in lymphangioleiomyomatosis (LAM) occurs as a result of excessive proliferation of LAM cells caused by a mutation in one of the tuberous sclerosis complex suppressor genes, TSC1 or TSC2. These cells show constitutive activation of the mammalian target of rapamycin (mTOR) pathway and many of the mTOR-related kinases such as Akt, Erk, S6K1 and S6. Phenotype of LAM cells differs considerably depending on their microenvironment. LAM cells show differences in morphology, size and expression of various factors depending on their location in the tumor or body fluids. The presence of LAM cells in blood, urine, bronchoalveolar lavage fluid (BALF), and chyle proves their ability to metastasis. Antigens of smooth muscle cells are expressed in most LAM cells. Some of these cells are immunoreactive with HMB-45 antibody, which is used for the immunohistochemical diagnosis of LAM. Receptors for estrogen and progesterone may also be expressed in these cells, which probably is associated with the fact that LAM occurs almost exclusively in women of childbearing age. LAM cells via increased production of metalloproteinases are involved in the destruction of the extracellular matrix, as well as the remodeling and damage of lung tissue. Sporadic LAM occurs extremely rarely. Therefore a good experimental model of this disease is necessary. To date, several animal and human cell lines, which both genetically and phenotypically resemble LAM cells, have been obtained. These cell lines, derived from LAM nodule or an angiomyolipoma, are usually characterized by a mutation of the TSC2 gene, expression of smooth muscle cell antigens such as a-smooth muscle actin (aSMA) or S6K1 and S6 protein hyperphosphorylation. Presently, there is no commercially available cell line representing a good model of LAM. A better understanding of LAM cell biology is necessary for creating a useful model in vitro for further exploration of both LAM pathomechanisms and more general mechanisms of carcinogenesis.

Massage-induced morphological changes of dense connective tissue in rat's tendon

The aim of the experiment was to determine if possible changes in connective tissue induced by massage could have a positive effect justifing the use of massage in all post-traumatic connective tissue conditions, e.g. tendon injuries. The investigations were performed in a group of 18 Buffalo rats. The rats were divided into two groups (experimental and control). To standardize the massage procedure, it was performed with an algometer probe of 0.5 cm2 with constant pressure force of 1 kG (9,81 N). To analyse the number and diameter of collagen fibrils, two electron micrographs were performed for each rat of the collected segments of tendons of rat tail lateral extensor muscle. After image digitalization and calibration, the measurements were carried out using iTEM 5.0 software. The number of fibrils, their diameter and area were measured in a cross-sectional area. An increase of the number of collagen fibrils was observed in the tendons of massaged animals compared to the control group. Our study demonstrated that massage may cause a beneficial effect on metabolic activity of tendon's fibroblasts and, in consequence, may be applied for more effective use of massage for the prevention of tendon injury as well as after the injury has occurred. (Folia Histochemica et Cytobiologica 2013, Vol. 51, No. 1, 103-106).

Podoplanin expression in cancer-associated fibroblasts correlates with VEGF-C expression in cancer cells of invasive ductal breast carcinoma

Podoplanin (D2-40) was shown to be expressed in cancer-associated fibroblasts (CAFs) of various malignancies. The study aimed at examining its impact on angiogenesis and lymphangiogenesis markers in invasive ductal carcinoma of the breast (IDC). The studies were performed on 104 archival cases of IDC using immunohistochemical technique. Podoplanin expression in CAFs correlated positively with cancer cell VEGF-C expression (r=0.19, p=0.0495) and intratumoral microvessel count (MVC) of CD31 positive vessels (r=0.30, p=0.0018), whereas negative correlations were observed with peritumoral MVC of D2-40 and Lyve-1 positive lymphatic vessels (r=-0.26, p=0.008 and r=-0.27, p=0.0058, respectively). Podoplanin expression in CAFs did not correlate with VEGF-A and VEGF-D expression in cancer cells, nor exerted any prognostic significance. Podoplanin expression in CAFs may have impact on angio- and lymphangiogenesis processes in IDC.

Prolonged exposure to inhaled nitric oxide transiently modifies tubular function in healthy piglets and promotes tubular apoptosis

AIM

Inhaled nitric oxide (iNO) is a selective pulmonary vasodilator. We hypothesized that those piglets exposed to prolonged iNO react with a modified renal function.

METHODS

Randomized, placebo-controlled exposure to 40 p.p.m. iNO (30 h) in piglets (n = 20). Plasma and urine were sampled during three periods (first and second 12 h periods, and finally a 6 h period). We measured urine volumes, plasma and urine electrolytes (UNa, UK, UCl), plasma creatinine and urea. We calculated creatinine clearance (Ccr), and fractional excretions of sodium and potassium (FENa, FEK) and urinary excretions of electrolytes (UENa, UEK, UECl). Haemodynamic data were recorded and renal tubular apoptosis detected.

RESULTS

For the first 12 h, certain parameters significantly increased in the iNO group (mean +/- SD): UNa (mmol L(-1)), 87.7 (+/-35.0) vs. 39.3 (+/-22.9), UCl (mmol L(-1)) 80.4 (+/-32.8) vs. 48.0 (+/-26.7), FENa (%) 2.1 (+/-0.8) vs. 0.7 (+/-0.5), FEK (%) 31.7 (+/-7.0) vs. 20.7 (+/-12.3), as well as UENa (mmol) 61.0 (+/-21.1) vs. 27.6 (+/-17.9) and UECl (mmol) 57.3 (24.5) vs. 37.6 (29.0). These changes were absent in the second and third periods of the study. Significant differences in percentage of apoptotic cell nuclei in the renal cortex and medulla were found after iNO exposure: 39% vs. 15%.

CONCLUSION

Exposure to 40 p.p.m. iNO in healthy anaesthetized piglets has a transient natriuretic effect that disappears after 12 h. We also found evidence of renal tubular apoptosis promotion after 30 h of iNO.

Exercise-induced apoptosis in rat kidney is mediated by both angiotensin II AT1 and AT2 receptors

Excessive physical exercise may lead to disturbance of the entire homeostasis in the body, including damage not only in skeletal muscles but also in many distant organs. The mechanisms responsible for the exercise-induced changes could include oxidative stress or angiotensin II. We previously showed that acute exercise led to apoptosis in kidney but not as a result of oxidative stress. In this study, we examined the role of angiotensin II and its AT1 and AT2 receptors in mediation of exercise-induced apoptosis in kidney. We clearly demonstrated that acute physical exercise induced apoptosis in renal cells of distal convoluted tubuli and cortical and medullary collecting ducts. Moreover, the cells displayed an increased expression of both AT1 and AT2 angiotensin II receptors and of p53 protein. The results suggest that angiotensin II could upregulate p53 expression in renal distal convoluted tubular cells and in the cells collecting ducts via both AT1 and AT2 receptors, which might be the crucial apoptosis-mediating mechanism in kidneys after excessive exercise.

Apoptosis of myofibres and satellite cells: exercise-induced damage in skeletal muscle of the mouse

Apoptosis is well accepted as a type of cell death occurring in the development of mammalian muscles, but the death of adult myofibres in neuromuscular disorders and exercise-induced muscle damage is usually explained in terms of muscle necrosis. The current view that apoptosis precedes necrosis in death of dystrophin-deficient muscle fibres of mdx mouse has been well substantiated. Moreover, apoptotic myonuclei have been reported to increase in mdx mice 2 days after spontaneous exercise. To investigate the contribution of apoptosis to exercise-induced damage of normal muscle fibre a time-course analysis has been performed in adult C57BL/6 mice. Groups of five mice were sacrificed immediately after the end of the exercise, and after a rest period of 6 or 96 h. The amount of apoptosis in leg muscles was assessed by electron microscopy, by the terminal deoxynucleotidyl transferase assay and by electrophoretic detection of fragmented DNA; the expression of Bcl-2, Bax, Fas, ICE, p53 and ubiquitin was examined by immunohistochemistry and Western blot. Absent in muscles of normal 'sedentary' mice, apoptotic myonuclei peak in muscles of normal mice after a night of spontaneous wheel-running (4% +/- 3.5, immediately and 2.5% +/- 1.8 after 6 h rest, P < 0.05 vs non-runner mice); they then decrease but are present 4 days later (0.8% +/- 1.5). Satellite cells are also involved in the apoptotic process. Myofibre content of Bcl-2 decreases whereas Bax, Fas, ICE and ubiquitin modify their pattern of expression in correlation with the changes in apoptotic myonuclei. Apoptosis of endothelial cells is present after the night of wheel-running and with a twofold increase 4 days later (1.5 +/- 2.3 and 4.8 +/- 4.4 P < 0.05, respectively). Satellite cells are also involved in the apoptotic process. Thus, spontaneous running in unaccustomed mice increases the number of apoptotic nuclei in adult muscle fibres and in endothelial cells. It remains to be established whether muscle apoptosis is restricted to the repair mechanisms, as often suggested in many pathologic processes, or it is also part of pathogenesis of muscle damage. Regardless of whether these results are extended to human dystrophies, the clinical implications in terms of secondary pathogenetic mechanisms and muscle training are obvious.

Smooth muscle myosin light chain kinase is transiently expressed in skeletal muscle during embryogenesis and muscle regeneration both in vivo and in vitro

By using a polyclonal antibody raised against smooth muscle Myosin Light Chain Kinase of adult chicken we show that the 135 kDa smooth muscle Myosin Light Chain Kinase isoform is present in neonatal and regenerating rat skeletal muscle, as well as in adult atrial myocardium. No reaction was evident in adult skeletal muscle fibres. In neonatal and in early regenerating muscle smooth muscle Myosin Light Chain Kinase is associated with embryonic myosin as revealed by their co-presence in muscle fibres. Experiments in vitro show the same results in myotubes. In atrial myocardium there is a patchy positivity in certain group of myocytes. Immunoblotting experiments show in muscle cell cultures, in neonatal and in regenerating skeletal muscle a protein band with electrophoretic mobility corresponding to that of smooth muscle Myosin Light Chain Kinase. These results suggest that the expression of smooth muscle Myosin Light Chain Kinase is not fully tissue-specific and that regulation of the contractile machinery could be different during myogenesis and in adulthood, in relation to the peculiar dynamic characteristics of developing muscles.

Exercise induces myonuclear ubiquitination and apoptosis in dystrophin-deficient muscle of mice

Apoptosis plays a major role in several diseases, including viral infections, autoimmune diseases, cancer, cardiac infarct, and neurological disorders. To investigate the role of apoptosis in muscular dystrophy, dystrophin-deficient (mdx) mice were subjected to spontaneous exercise and skeletal muscles were analyzed for apoptosis and ubiquitin. The increase of apoptotic myonuclei after exercise was detected by TUNEL, by electron microscopy, and by DNA analyses for high molecular weight and for ladder fragments. Expression of ubiquitin correlated with exercise and with positive myonuclei for apoptosis. Biochemical analysis confirmed a high level of ubiquitination both in sarcoplasmic and myofibrillar proteins. Muscles from sedentary congenit control mice (C57B ) were negative for apoptosis, while after exercise some nuclei were positive. We also revealed that normal myoblasts committed to apoptosis in vitro showed an increased expression of ubiquitin. Western blot for bcl-2, FasL, and BAG1 showed a significant decrease of bcl-2 product only in mdx mice after exercise. Thus, spontaneous exercise results in the increase of ubiquitin expression and in the reduction of bcl-2 tightly related to programmed cell death in mdx mice. These findings confirm that DNA fragmentation, absent in muscles of sedentary normal mice but present in mdx mice at rest, dramatically increases after exercise, shedding new light on exercise-induced muscle damage and on its progression in dystrophinopathies.