The role of HSP27 in the development of drug resistance of gastrointestinal malignancies: Current status and perspectives

Heat-shock protein 27 (HSP27) is a chaperone molecule that plays a critical role in the refolding and activity of several proteins responsible for cancer cell drug toxicity. Upregulation of HSP27 is associated with decreased drug sensitivity as well as poorer survival in gastrointestinal (GI) malignancies. It is, therefore, possible that HSP27 may be of value in the assessment of prognostic and therapeutic efficacy in the treatment of GI cancers. Pharmacological and biological inhibitors of HSP27 enhance tumor cell chemosensitivity. This review summarizes the potential role of HSP27 in chemotherapy drug resistance and the therapeutic potential of HSP27 inhibitors as a novel strategy in the treatment of GI cancers.     

Isolation murine mesenchymal stem cells by positive selection

Isolation and purification of mesenchymal stem cells (MSCs) from mouse via plastic adherent cultures is arduous because of the unwanted growth of hematopoietic cells and non-MSCs. In this work, homogenous populations of CD34⁺ MSCs from mouse bone marrow were isolated via positive selection. For this purpose, C57Bl/6 mice were killed and bone marrow cells were aspirated before incubation with magnetic bead conjugated to anti-CD34 antibody. A sample of positively selected CD34⁺ cells were prepared for flow cytometry to examine the expression of CD34 antigen and others were subcultured in a 25-cm² culture flask. To investigate the mesenchymal nature, the plastic adherent cultivated cells were induced to differentiate along osteoblastic and adipogenic lineages. Furthermore, the expression of some surface markers was investigated by flow cytometry. According to the result, purified populations of fibroblast-like CD34⁺ cells were achieved in the first passage (1 wk after culture initiation). The cells expressed CD34, CD44, Sca-1, and Vcam-1 antigens (markers) but not CD11b and CD45. They were capable of differentiating into osteocytes and adipocytes. This study indicated that our protocol can result in the efficient isolation of homogenous populations of MSCs from C57BL/6 mouse bone marrow. We have shown that murine bone marrow-derived CD34⁺ cells with plastic adherent properties and capability of differentiating into skeletal lineages in vitro are MSCs.     

Tube Formation Potential of BMSCs and USSCs in Response to HIF-1α Overexpression under Hypoxia

Despite numerous studies on therapeutic effects of mesenchymal stem cells on ischemic tissue regeneration, including angiogenesis, their mechanism of action remains ambiguous. Due to the scarce of investigations based on different stem cell sources with known inherent molecular differences, present study compare tube formation of Bone marrow Mesenchymal Stem Cells and Unrestricted Somatic Stem Cells with known reported different Hox gene expression profile in response to HIF-1α overexpression under hypoxia. This might shed light on some parameters for selection of more responsive source with improved therapeutic effects. Superior in vitro tube formation on Matrigel substratum has been observed by Unrestricted Somatic Stem Cells compared to Bone marrow Mesenchymal Stem Cells which might possibly be due to the discriminating molecular properties of stem cell sources. It may help choosing the appropriate stem cell type for a given therapeutic expectations and also suggests some potential targets for future genetic modification of stem cells.     

Electrical impedance tomography imaging using a priori ultrasound data

Transverse propagation was previously found to occur in a two-dimensional model of cardiac muscle using the PSpice software program for electronic circuit design and analysis. Longitudinal propagation within each chain, and transverse propagation between parallel chains, occurred even when there were no gap-junction (g-j) channels inserted between the simulated myocardial cells either longitudinally or transversely. In those studies, there were pronounced edge (boundary) effects and end-effects even within single chains. Transverse velocity increased with increase in model size. The present study was performed to examine boundary effects on transverse propagation velocity when the length of the chains was held constant at 10 cells and the number of parallel chains was varied from 3 to 5, to 7, to 10, and to 20. The number of g-j channels was either zero, both longitudinally and transversely (0/0), or 100/100. Some experiments were also made at 100/0, 1/1, and 10/10. Transverse velocity and overall velocity (both longitudinal and transverse components) was calculated from the measured total propagation time (TPT), i.e., the elapsed time between when the first action potential (AP) and the last AP crossed the zero potential level. The transverse g-j channels were placed only at the ends of each chain, such that propagation would occur in a zigzag pattern. Electrical stimulation was applied intracellularly between cells A1 and A2. It was found that, with no g-j channels (0/0), overall velocity increased almost linearly when more and more chains were placed in parallel. In contrast, with many g-j channels (100/100), there was a much flatter relationship between overall velocity and number of parallel chains. The difference in velocities with 0/0 channels and 100/100 channels was reduced as the number of chains was increased. In conclusion, edges have important effects on propagation velocity (overall and transverse) in cardiac muscle simulations.     

Simultaneous application of cisplatin and static magnetic field enhances oxidative stress in HeLa cell line

In this study, we reported the effects of simultaneous application of static magnetic field (SMF) and cisplatin as an anticancer drug on the oxidative stress in human cervical cancer (HeLa) cell line and normal skin fibroblast cells (Hu02). The cells were exposed to different SMF intensities (7, 10, and 15 mT) for 24 and 48 h. IC₅₀ concentrations of cisplatin were obtained by MTT assay. The cytotoxic effects of combined treatment were studied by measuring the intracellular reactive oxygen species content using flow cytometric method and estimation of membrane lipid peroxidation by spectrophotometry. Statistical analysis was assessed using one-way repeated measures analysis of variance (ANOVA) followed by Tukey’s test. Based on the obtained results, the highest and lowest death rate, respectively, in HeLa and Hu02 cell lines was observed at the intensity of 10 mT. Also, we found that membrane lipid peroxidation in cancer cells is higher than that of normal counterparts. SMF potently sensitized human cervical cancer cells to cisplatin through reactive oxygen species (ROS) accumulation while it had small effects on normal cells. The combination of both treatments for 48 h led to a marked decrease in the viability percentage of HeLa cells by about 89% compared to untreated cells. This study suggests that conjugation of both physical and chemical treatments could increase the oxidative stress in HeLa cell line and among three optional intensities of SMF, the intensity of 10 mT led to the higher damage to cancer cells in lower doses of drug.     

Therapeutic potency of pharmacological adenosine receptors agonist/antagonist on cancer cell apoptosis in tumor microenvironment,current status,and perspectives

The hypoxic niche of tumor leads to a tremendous increase in the extracellular adenosine concentration through alteration of adenosine metabolism in the tumor microenvironment (TME). This consequently affects cancer progression, local immune responses, and apoptosis of tumor cells. Regulatory effect of adenosine on apoptosis in TME depends on the cancer cell type, pharmacological characteristics of adenosine receptor subtypes, and the adenosine concentration in the tumor niche. Exploiting specific pharmacological adenosine receptor agonist and antagonist inducing apoptosis in cancer cells can be considered as a proper procedure to control cancer progression. This review summarizes the regulatory role of adenosine in cancer cell apoptosis for a better understanding, and hence better management of the disease.     

Angiotensin II type 1 receptor blockade attenuates TGF-beta-induced failure of muscle regeneration in multiple myopathic states

Skeletal muscle has the ability to achieve rapid repair in response to injury or disease. Many individuals with Marfan syndrome (MFS), caused by a deficiency of extracellular fibrillin-1, exhibit myopathy and often are unable to increase muscle mass despite physical exercise. Evidence suggests that selected manifestations of MFS reflect excessive signaling by transforming growth factor (TGF)-beta (refs. 2,3). TGF-beta is a known inhibitor of terminal differentiation of cultured myoblasts; however, the functional contribution of TGF-beta signaling to disease pathogenesis in various inherited myopathic states in vivo remains unknown. Here we show that increased TGF-beta activity leads to failed muscle regeneration in fibrillin-1-deficient mice. Systemic antagonism of TGF-beta through administration of TGF-beta-neutralizing antibody or the angiotensin II type 1 receptor blocker losartan normalizes muscle architecture, repair and function in vivo. Moreover, we show TGF-beta-induced failure of muscle regeneration and a similar therapeutic response in a dystrophin-deficient mouse model of Duchenne muscular dystrophy.     

Oral poliovirus vaccine in management of recurrent aphthous stomatitis

Oral poliovirus vaccine (OPV) is reported to be effective in treatment of recurrent herpes simplex (RHS). According to our observation during recent years, OPV was not only effective in management of RHS but also in some patients with concomitant recurrent aphthous stomatitis (RAS) reducing its severity and frequency. The purpose of this study was to evaluate the efficacy of OPV in the management of RAS. In a longitudinal, case--control study 48 patients with RAS were recruited. Twenty patients received OPV and 28 patients received placebo. OPV was administered in a dose of 4 drops at monthly intervals for 3 months to the study group while the control group received placebo. The results were registered in 3 months after the last dose. Eight cases (40%) in the OPV group showed significant reduction in the duration of the ulcers, while no change was seen in the control group (P = 0.048). The frequency of recurrence of RAS was reduced in 13 cases (65%) in the OPV group, and in 6 cases (21.4%) of the placebo group (P = 0.006). The severity of attacks was reduced in 12 cases (60%) in the OPV group and in 4 cases (14.3%) in the placebo group (P = 0.008). In conclusion OPV appeared to be effective in the management of RAS.     

Identification of stathmin as a novel marker of cell proliferation in the recovery phase of acute ischemic renal failure

Ischemic renal injury can be classified into the initiation and extension phase followed by the recovery phase. The recovery phase is characterized by increased dedifferentiated and mitotic cells in the damaged tubules. Suppression subtractive hybridization was performed by using RNA from normal and ischemic kidneys to identify the genes involved in the physiological response to ischemia-reperfusion injury (IRI). The expression of stathmin mRNA increased by fourfold at 24 h of reperfusion. The stathmin mRNA did not increase in sodium-depleted animals or in animals with active, persistent injury secondary to cis-platinum. Immunofluorescent labeling demonstrated that the expression of stathmin increased dramatically at 48 h of reperfusion. Labeling with antibodies to stathmin and proliferating cell nuclear antigen (PCNA) indicates that the expression of stathmin was induced before the upregulation of PCNA and that all PCNA-positive cells expressed stathmin. Double immunofluorescent labeling demonstrated the colocalization of stathmin with vimentin, a marker of dedifferentiated cells. Stathmin expression was also significantly enhanced in acute tubular necrosis in humans. On the basis of its induction profile in IRI, the data indicating its enhanced expression in proliferating cells and regenerating organs, we propose that stathmin is a marker of dedifferentiated, mitotically active epithelial cells that may contribute to tubular regeneration and could prove useful in distinguishing the injury phase from recovery phase in IRI.