The Effect of Tumor Resection and Radiotherapy on the Expression of Stem Cell Markers (CD44 and CD133) in Patients with Squamous Cell Carcinoma.

Background: Head and Neck Squamous Cell Carcinomas (HNSCCs) are heterogeneous malignancies that comprise 90% of the head and neck cancers. HNSCCs originate from the mucosal lining epithelium of the upper aerodigestive tract. Cancer stem cells (CSCs) that generate HNSCCs with the CD44, CD133, and ALDH phenotype and are resistant to radiotherapy and chemotherapy. In the current, the quantitative alteration in CD44 and CD133 expression pre- and post-tumor resection and radiotherapy was evaluated in HNSCC patients. Moreover, the alterations in the expression of Bax, Bak, Bcl-2, ALDH, and PTEN genes were measured. Materials and Methods: Flow cytometry was performed to evaluate the alterations in CD44 and CD133 surface markers pre- and posttumor resection and radiotherapy. Quantitative real-time RT-PCR (qRT-PCR) was conducted to investigate the mRNA expression levels of Bax, Bak, Bcl-2, ALDH, and PTEN. Results: The results indicated that the cancer stem cell CD44 surface marker significantly decreased after tumor resection and radiotherapy in HNSCC cases, while the decrease was insignificant for CD133 marker expression. mRNA expression level of Bcl-2 and ALDH was increased, but Bax and Bak gene expressions were reduced significantly Conclusion: The results also indicated that the expression of CD44 significantly decreased after tumor resection and radiotherapy. The upregulation of mRNA level of Bcl-2 and ALDH, and the downregulation of Bax and Bak gene expression were noted in these cases when compared to the healthy control group.

Oxadiazole Derivatives of Diclofenac as an Anti-proliferative Agent for B-cell Non-Hodgkin Lymphoma: An In vitro and In Silico Studies.

BACKGROUND: Non-Hodgkin lymphoma of B cell origin is the common type of lymphoma- related malignancy with poor response rate with conventional front-line therapies. AIM: The aim of the present study was to investigate the potential of new anti-inflammatory oxadiazole derivatives of Diclofenac as an anti-lymphoma agent through in vitro and in silico approaches. METHOD: The compound (II) showed anti-lymphoma activity against both follicular and Burkitt's lymphoma cells, whereas compound (V) inhibited follicular lymphoma cells only. The diclofenac (I) and derivatives (III, IV and VI) exhibited no anti-proliferative effects. The (II) significantly inhibited the expression of BCL-2, p-38 MAPK and TGF-ß in both follicular and Burkitt's lymphoma cells and was non-toxic against normal human fibroblast cells (BJ). RESULT: The in silico studies against BCL-2 revealed that the unsubstituted Sulphur group in compound (II) is involved in the crucial interactions with the binding site residue. CONCLUSION: The compound (II) can be a potential therapeutic candidate for B-cell non-Hodgkin lymphoma and deserves further development as a novel anti-lymphoma agent.

Crosstalk between Nrf2 signaling pathway and inflammation in ischemic stroke: Mechanisms of action and therapeutic implications.

One of the major causes of long-term disability and mortality is ischemic stroke that enjoys limited treatment approaches. On the one hand, oxidative stress, induced by excessive generation of reactive oxygen species (ROS), plays a critical role in post-stroke inflammatory response. Increased ROS generation is one of the basic factors in the progression of stroke-induced neuroinflammation. Moreover, intravenous (IV) thrombolysis using recombinant tissue plasminogen activator (rtPA) as the only medication approved for patients with acute ischemic stroke who suffer from some clinical restrictions it could not cover the complicated episodes that happen after stroke. Thus, identifying novel therapeutic targets is crucial for successful preparation of new medicines. Recent evidence indicates that the transcription factor Nuclear factor erythroid 2-related factor 2 (Nrf2) contributes significantly to regulating the antioxidant production in cytosol, which causes antiinflammatory effects on neurons. New findings have shown a relationship between activation of the Nrf2 and glial cells, nuclear factor kappa B (NF-κB) pathway, the nucleotide-binding domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) inflammasome signaling, and expression of inflammatory markers, suggesting induction of Nrf2 activation can represent a promising therapeutic alternative as the modulators of Nrf2 dependent pathways for targeting inflammatory responses in neural tissue. Hence, this review addresses the relationship of Nrf2 signaling with inflammation and Nrf2 activators' potential as therapeutic agents. This review helps to improve required knowledge for focused therapy and the creation of modern and improved treatment choices for patients with ischemic stroke.

The effect of mitochondria inhibition on natural killer cells cytotoxicity in triple-negative breast cancer cells.

Triple-Negative Breast Cancer (TNBC), the most common invasive breast cancer, depicts cancer poor response to conventional therapies. The clinical management of TNBC is a challenging issue. Natural killer (NK) cell therapy in the field of cancer treatment is rapidly growing however, regarding the immunogenicity of breast cancer cells, this type of therapy has shown limited efficacy. Recently, targeting tumor biomarkers has revolutionized the field of cancer therapy. Mitochondria affects apoptosis and innate immunity. Therefore, in this study, mitochondria were inhibited with Tigecycline in stimulating the cytotoxicity of NK cells against TNBC cell lines. MDA-MB-468 and MDA-MB-231 were cultured and treated with IC50 (the half-maximal inhibitory concentration) level of Tigecycline for 48 h and afterward co-cultured with peripheral blood NK cells for 5 h. Lastly, the inhibitory effects of mitochondria on the cytotoxicity of NK cells and apoptosis of TNBC cells were evaluated. Moreover, the expression of apoptotic-related genes was studied. The results showed that mitochondria inhibition increased NK cells cytotoxicity against TNBC cells. Moreover, NK cell/mitochondria inhibition in a combinative form improved apoptosis in TNBC cells by the upregulation of Bad and Bid expression. In conclusion, Tigecycline inhibited mitochondria and sensitized TNBC cells to NK cell therapy. Therefore, mitochondria inhibition could help NK cells function properly.

Dysregulation of Type I Interferon (IFN-I) Signaling: A Potential Contributor to Racial Disparity in Hepatocellular Carcinoma (HCC).

African-American (AA)/Black hepatocellular carcinoma (HCC) patients have increased incidence and decreased survival rates compared to non-Hispanic (White) patients, the underlying molecular mechanism of which is not clear. Analysis of existing RNA-sequencing (RNA-seq) data in The Cancer Genome Atlas (TCGA) and in-house RNA-sequencing of 14 White and 18 AA/Black HCC patients revealed statistically significant activation of type I interferon (IFN-I) signaling pathway in AA/Black patients. A four-gene signature of IFN-stimulated genes (ISGs) showed increased expression in AA/Black HCC tumors versus White. HCC is a disease of chronic inflammation, and IFN-Is function as pro-inflammatory cytokines. We tested efficacy of ginger extract (GE), a dietary compound known for anti-inflammatory properties, on HCC cell lines derived from White (HepG2), AA/Black (Hep3B and O/20) and Asian (HuH-7) patients. GE exhibited a significantly lower IC50 on Hep3B and O/20 cells than on HepG2 and HuH-7 cells. The GE treatment inhibited the activation of downstream mediators of IFN-I signaling pathways and expression of ISGs in all four HCC cells. Our data suggest that ginger can potentially attenuate IFN-I-mediated signaling pathways in HCC, and cells from AA/Black HCC patients may be more sensitive to ginger. AA/Black HCC patients might benefit from a holistic diet containing ginger.

The dysfunction of natural killer cells is essential for the development of type 1 diabetes.

Type 1 diabetes (T1D) is characterized by destruction of pancreatic insulin-producing beta cells by immune cells. In general, environmental and genetic factors can lead to immunological self-tolerance in TID. It is clear that the innate immune system, especially natural killer (NK) cells, is involved in the pathogenesis of T1D. Aberrant NK cell frequencies associated with dysregulation of inhibitory and activating receptors contribute to the initiation and progression of T1D. As T1D is incurable and the metabolic disturbances caused by T1D severely impact patients, a better understanding of NK cell behavior in T1D may facilitate disease treatment strategies. The current review focuses on the role of NK cell receptors in T1D and also highlights ongoing efforts to manipulate key checkpoints in NK cell-targeted therapies.

Characterization of Green and Yellow Papaya (Carica papaya) for Anti-Diabetic Activity in Liver and Myoblast Cells and Wound-Healing Activity in Fibroblast Cells.

Obesity and diabetes, often characterized as "metabolic syndrome", have been recognized as two of the most important public health issues worldwide. The objective of the present research was to evaluate green and yellow papaya for anti-oxidation and anti-diabetic properties. Leaves, skin, pulp, and seed samples from papayas were freeze-dried and then extracted in water or 80% methanol. The extracts were used to determine total polyphenolic content and anti-oxidation activities, and to determine biological activities, including glucose uptake, Glut-2 expression, triglyceride reduction, and wound-healing activity. Our data demonstrated that methanol and water extracts of green and yellow papaya have similar concentrations of polyphenols in skin (10-20 mg/g dry powder), leaf (25-30 mg/g dry powder), and pulp (1-3 mg/g dry powder) fractions. However, both methanol and water extracts of seeds from yellow papaya have substantially higher concentrations of polyphenols compared to green papaya. Both water and methanol extracts of yellow papaya exhibited higher anti-oxidation activity compared to green papaya in skin (50-60%), pulp (200-300%), and seeds (10-800%). Old leaves also showed greater anti-oxidation activity (30-40%) compared to new leaves. Pulp extracts from both yellow and green papaya stimulated greater glucose uptake, but only pulp from green papaya stimulated glucose uptake in muscle cells. Similarly, pulp extract stimulated glucose transporter Glut-2 expression in liver cells. The skin, pulp, and seeds of green or yellow papaya showed triglyceride-lowering activity in liver cells by 60-80%, but samples taken from yellow papaya had a more potent effect. Seeds from both green and yellow papaya significantly stimulated the migration of fibroblasts in the wounded area by 2-2.5-fold compared to the untreated control. Consistent with these data, seeds from both green and yellow papaya also significantly stimulated collagen synthesis in fibroblast cells by almost 3-fold. In conclusion, our data indicate that different parts of papaya produce stimulatory effects on glucose uptake, Glut-2 expression, TG reduction, and wound-healing activities. This study concludes that different parts of the papaya can be beneficial for preventing diabetes and diabetes-related wound healing.

The Effect of Telomerase Inhibition on NK Cell Activity in Acute Myeloid Leukemia.

Purpose: Acute myeloid leukemia (AML) is known to be an invasive and highly lethal hematological malignancy in adults and children. Resistance to the present treatments, including radiotherapy and chemotherapy with their side effects and telomere length shortening are the main cause of the mortality in AML patients. Telomeres sequence which are located at the end of eukaryotic chromosome play pivotal role in genomic stability. Recent studies have shown that apoptosis process is blocked in AML patient by the excessive telomerase activity in cancerous blasts. Therefore, the find of effective ways to prevent disease progression has been considered by the researchers. Natural killer (NK) cells as granular effector cells play a critical role in elimination of abnormal and tumor cells. Given that the cytotoxic function of NK cells is disrupted in the AML patients, we investigated the effect of telomerase inhibitors on NK cell differentiation. Methods: To evaluate telomerase inhibition on NK cell differentiation, the expression of CD105, CD56, CD57, and KIRs was evaluated in CD34+ derived NK cells after incubation of them with BIBR1532. Results: The results showed that the expression of CD105, CD56, CD57, and KIRs receptors reduces after telomerase inhibition. According to these findings, BIBR1532 affected the final differentiation of NK cells. Conclusion: The results revealed that telomerase inhibitor drugs suppress cancer cell progression in a NK cells-independent process.

Cord blood stem cell-generated KIR+NK cells effectively target leukemia cell lines.

Acute lymphoid (ALL) and myeloid leukemia (AML) are known to be invasive and highly lethal hematological malignancies. Because current treatments are insufficient and have a variety of side effects, researchers are looking for new and more effective therapeutic methods. Interestingly, ongoing efforts to find the best approach to optimize NK cell anti-leukemia potential shed light on the successful treatment of cancer. Mature KIR+NK cells ability to remove HLA Class-I deficient cells has been exploited in cancer immunotherapy. Here, we generated KIR+NK cells from cord blood stem cells using IL-2 and IL-15 cytokines. Our finding underlined the importance of KIR expression in the cytotoxic function of NK cells. Taken together, this study presented an effective in vitro method for the expansion and differentiation of KIR+NK cells using cytokines without any feeder cells. Furthermore, the presented culture condition could be useful for the generation of mature and pure NK cells from limited numbers of CD34+ cord blood cells and might be used as a novel method to improve the current state of cancer therapy.

A combination of telomerase inhibition and NK cell therapy increased breast cancer cell line apoptosis.

Triple-negative breast cancer (TNBC) is a subtype of breast tumor with the highest breast cancer stem cells (BCSCs) content and resistance to conventional treatment. Due to the immunosuppressive tumor microenvironment and immunogenicity of breast cancer cells, the use of immune cells, especially natural killer cells (NK) in the treatment of solid tumors, including breast cancer, has been unsatisfactory. Therefore, identifying novel therapies is requisite for breast cancer treatment. Furthermore, the combination of cancer therapies is an effective strategy to improve therapeutic effectiveness. In this study, we inhibited telomerase (hTERT) with BIBR1532, in stimulating NK cell cytotoxicity against breast cancer cells. The MDA-MB-231 cell line was cured with IC50 level of BIBR1532 for 24 h. Afterward, cells were washed with PBS and were co-cultured with peripheral blood NK cell for 5h. Finally, we assessed the impact of telomerase inhibition on the cytotoxicity of NK cells and apoptosis of breast cancer. Also, the expression of hTERT and apoptotic-related genes were evaluated. The data revealed that inhibition of telomerase increases NK cell cytotoxicity against breast cancer. Furthermore, telomerase inhibition and NK cell synergistically enhanced cell death in breast cancer cells by suppressing hTERT, upregulation of bax, and bad expression. In conclusion, telomerase suppression makes breast cancer cells more sensitive to NK cell therapy. Consequently, the combination of telomerase inhibition and NK cells can be useful in the treatment of breast cancer cells.

NK cell dysfunction is linked with disease severity in SARS-CoV-2 patients.

SARS-CoV-2 first raised from Wuhan City, Hubei Province in November 2019. The respiratory disorder, cough, weakness, fever are the main clinical symptoms of coronavirus disease 2019 (COVID-19) patients. Natural Killer (NK) cells as a first defense barrier of innate immune system have an essential role in early defense against pulmonary virus. They kill the infected cells by inducing apoptosis or the degranulation of perforin and granzymes. Collectively, NK cells function are coordinated by the transmitted signals from activating and inhibitory receptors. It is clear that the cytotoxic function of NK cells is disrupted in COVID-19 patients due to the dysregulation of activating and inhibitory receptors. Therefore, better understanding of the activating and inhibitory receptors mechanism could facilitate the treatment strategy in clinic. To improve the efficacy of immunotherapy in COVID-19 patients, the functional detail of NK cell and manipulation of their key checkpoints are gathered in current review.

Bone marrow CD34 positive cells may be suitable for collection after death.

Hematopoietic stem cells (HSCs) which are characterized with CD34+ phenotype, have a pivotal role in blood cell regeneration. They are located in lowest hypoxic areas in the bone marrow niches. This microenvironment protects them from DNA damage and excessive proliferation, whereas the oxygenated area driving cells out of quiescent state into proliferation. Given the resistance of HSCs to hypoxia, it is reasonable to imagine that they can survive for some time in the absence of oxygen. Here, we evaluated CD34, Bax, Bcl-2, Bcl-xl, and p53 genes expression after death. Moreover, we established the ex-vivo development of HSCs using SCF, FLT3, IL-2, and IL-15 cytokines in culture system. Our finding indicated that although the most of the dead person's mononuclear cells were alive and adequately expressed the CD34 on their surfaces at the first day of isolation, the viability and CD34+/Ki-67 expression declined significantly after culture process. Taken together, our finding indicated that the viability and CD34+ expression was acceptable on day 0 and could be used as a novel method for therapeutic purposes.

Effect of aberrant DNA methylation on cancer stem cell properties.

DNA methylation, as an epigenetic mechanism, occurs by adding a methyl group of cytosines in position 5 by DNA methyltransferases and has essential roles in cellular function, especially in the transcriptional regulation of embryonic and adult stem cells. Hypomethylation and hypermethylation cause either the expression or inhibition of genes, and there is a tight balance between regulating the activation or repression of genes in normal cellular activity. Abnormal methylation is well-known hallmark of cancer development and progression and can switch normal stem cells into cancer stem cells. Cancer Stem Cells (CSCs) are minor populations of tumor cells that exhibit unique properties such as self-regeneration, resistance to chemotherapy, and high ability of metastasis. The purpose of this paper is to show how aberrant DNA methylation accumulation affects self-renewal, differentiation, multidrug-resistant, and metastasis processes in cancer stem cells.

Telomerase-based therapies in haematological malignancies.

Telomeres are specialized genetic structures present at the end of all eukaryotic linear chromosomes. They progressively get shortened after each cell division due to end replication problems. Telomere shortening (TS) and chromosomal instability cause apoptosis and massive cell death. Following oncogene activation and inactivation of tumour suppressor genes, cells acquire mechanisms such as telomerase expression and alternative lengthening of telomeres to maintain telomere length (TL) and prevent initiation of cellular senescence or apoptosis. Significant TS, telomerase activation and alteration in expression of telomere-associated proteins are frequent features of different haematological malignancies that reflect on the progression, response to therapy and recurrence of these diseases. Telomerase is a ribonucleoprotein enzyme that has a pivotal role in maintaining the TL. However, telomerase activity in most somatic cells is insufficient to prevent TS. In 85-90% of tumour cells, the critically short telomeric length is maintained by telomerase activation. Thus, overexpression of telomerase in most tumour cells is a potential target for cancer therapy. In this review, alteration of telomeres, telomerase and telomere-associated proteins in different haematological malignancies and related telomerase-based therapies are discussed.

Telomerase inhibition on acute myeloid leukemia stem cell induced apoptosis with both intrinsic and extrinsic pathways.

AIMS: Acute Myeloid Leukemia (AML) is an invasive and lethal blood cancer caused by a rare population of Leukemia Stem Cells (LSCs). Telomerase activation is a limitless self-renewal process in LSCs. Apart from telomerase role in telomere lengthening, telomerase (especially hTERT subunit) inhibits intrinsic-, extrinsic-, and p53- mediated apoptosis pathways. In this study, the effect of Telomerase Inhibition (TI) on intrinsic-, extrinsic-, p53-mediated apoptosis, and DNMT3a and TET epigenetic markers in stem (CD34+) and differentiated (CD34-) AML cells is evaluated. MAIN METHODS: High-purity CD34+ (primary AML and KG-1a) cells were enriched using the Magnetic-Activated Cell Sorting (MACS) system. CD34+ and CD34- (primary AML and KG-1a) cells were treated with BIBR1532 and then, MTT assay, Annexin V/7AAD, Ki-67 assay, Telomere Length (TL) measurement, and transcriptional alterations of p53, hTERT, TET2, DNMT3a were analyzed. Finally, apoptosis-related genes and proteins were studied. KEY FINDINGS: TI with the IC50 values of 83.5, 33.2, 54.3, and 24.6 µM in CD34+ and CD34- (primary AML and KG-1a) cells significantly inhibited cell proliferation and induced apoptosis. However, TI had no significant effect on TL. The results also suggested TI induced intrinsic-, extrinsic-, and p53-mediated apoptosis. It was shown that the expression levels of DNMT3a and TET2 epigenetic markers were highly increased following TI. SIGNIFICANCE: In total, it was revealed that TI induced apoptosis through intrinsic, extrinsic, and p53 pathways and increased the expression of DNMT3a and TET2 epigenetic markers.

The role of KIR positive NK cells in diseases and its importance in clinical intervention.

Natural killer (NK) cells are essential for the elimination of the transformed and cancerous cells. Killer cell immunoglobulin-like receptors (KIRs) which expressed by T and NK cells, are key regulator of NK cell function. The KIR and their ligands, MHC class I (HLA-A, B and C) molecules, are highly polymorphic and their related genes are located on 19 q13.4 and 6 q21.3 chromosomes, respectively. It is clear that particular interaction between the KIRs and their related ligands can influence on the prevalence, progression and outcome of several diseases, like complications of pregnancy, viral infection, autoimmune diseases, and hematological malignancies. The mechanisms of immune signaling in particular NK cells involvement in causing pathological conditions are not completely understood yet. Therefore, better understanding of the molecular mechanism of KIR-MHC class I interaction could facilitate the treatment strategy of diseases. The present review focused on the main characteristics and functional details of various KIR and their combination with related ligands in diseases and also highlights ongoing efforts to manipulate the key checkpoints in NK cell-based immunotherapy.

Barcoded DNA origami structures for multiplexed optimization and enrichment of DNA-based protein-binding cavities.

Simultaneous binding of molecules by multiple binding partners is known to strongly reduce the apparent dissociation constant of the corresponding molecular complexes, and can be used to achieve strong, non-covalent molecular interactions. Based on this principle, efficient binding of proteins to DNA nanostructures has been achieved previously by placing several aptamers in close proximity to each other onto DNA scaffolds. Here, we develop an approach for exploring design parameters, such as the geometric arrangement or the nanomechanical properties of the binding sites, that use two-dimensional DNA origami-based nanocavities that bear aptamers with known mechanical properties at defined distances and orientations. The origami structures are labelled with barcodes, which enables large numbers of binding cavities to be investigated in parallel and under identical conditions, and facilitates a direct and reliable quantitative comparison of their binding yields. We demonstrate that binding geometry and mechanical properties have a dramatic effect on origami-based multivalent binding sites, and that optimization of linker spacings and flexibilities can improve the effective binding strength of the sites substantially.

Naringenin protects AlCl3/D-galactose induced neurotoxicity in rat model of AD via attenuation of acetylcholinesterase levels and inhibition of oxidative stress.

Currently prescribed medications for the treatment of Alzheimer's disease (AD) that are based on acetylcholinesterase inhibition only offer symptomatic relief but do not provide protection against neurodegeneration. There appear to be an intense need for the development of therapeutic strategies that not only improve brain functions but also prevent neurodegeneration. The oxidative stress is one of the main causative factors of AD. Various antioxidants are being investigated to prevent neurodegeneration in AD. The objective of this study was to investigate the neuroprotective effects of naringenin (NAR) against AlCl3+D-gal induced AD-like symptoms in an animal model. Rats were orally pre-treated with NAR (50 mg/kg) for two weeks and then exposed to AlCl3+D-gal (150 mg/kg + 300 mg/kg) intraperitoneally for one week to develop AD-like symptoms. The standard drug, donepezil (DPZ) was used as a stimulator of cholinergic activity. Our results showed that NAR pre-treatment significantly protected AD-like behavioral disturbances in rats. In DPZ group, rats showed improved cognitive and cholinergic functions but the neuropsychiatric functions were not completely improved and showed marked histopathological alterations. However, NAR not only prevented AlCl3+D-gal induced AD-like symptoms but also significantly prevented neuropsychiatric dysfunctions in rats. Results of present study suggest that NAR may play a role in enhancing neuroprotective and cognition functions and it can potentially be considered as a neuroprotective compound for therapeutic management of AD in the future.

Prevention of cadmium-induced neurotoxicity in rats by essential nutrients present in nuts.

Cadmium, a heavy metal with no physiological function in the human body, is considered a bio-hazard. It is also considered to be a potent neurotoxin. The primary sources of cadmium exposure are diet and cigarette smoke. It has been postulated that nutritional deficiencies can increase the risk of cadmium toxicity. Nuts provide essential nutrients which are necessary for the maintenance of brain health in humans. The present study was designed to investigate the possible protective effects of almond and walnut supplementation on cadmium-induced neurotoxicity. Cadmium was orally administered at a dose of 50 mg/kg weekly with or without the supplementation of almond and walnut in rats. Intensities of depression­ and anxiety-related behaviors were assessed by the forced swim test and light/dark transition test, respectively. Memory function was also evaluated by the elevated plus maze, Morris water maze and novel object recognition task. After four weeks of treatment it was observed that cadmium administration significantly induced depressogenic and anxiogenic behaviors. Memory function was also impaired by cadmium administration. Cadmium-treated rats exhibited reduced noradrenalin, dopamine and serotonin levels in the brain, whereas the levels of their respective metabolites were significantly increased. The dietary supplementation of almond and walnut at a dose of 400 mg/kg/day significantly attenuated cadmium-induced depression, anxiety and memory impairments. Neurochemical aberrations also normalized following supplementation with these nuts in rats. The present study demonstrates that long-term supplementation with almond and walnut provides essential nutrients which may overcome nutritional deficiencies and thereby reduce heavy-metal intoxication.

Comparison of The Melatonin Preconditioning Efficacy between Bone Marrow and Adipose-Derived Mesenchymal Stem Cells.

OBJECTIVE: Mesenchymal stem cells (MSC) from various sources have the potentials to positively affect regenerative medicine. Furthermore, pre-conditioning strategies with different agents could improve the efficacy of cell therapy. This study compares the effects of an anti-inflammatory and antioxidant agent, melatonin, on protection of bone marrow-derived MSCs (BMSCs) and adipose tissue-derived MSCs (ADSCs). MATERIALS AND METHODS: In this experimental study, rat BMSCs and ADSCs were isolated and expanded. Pre-conditioning was performed with 5 µM melatonin for 24 hours. Cell proliferation and viability were detected by MTT assay. Expression of BAX, BCL2, melatonin receptors and osteocalcin genes were evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR). Also, apoptosis was detected with tunnel assay. Osteogenic differentiation was analyzed using alizarin red staining. RESULTS: No significant increase was found in cell viability between BMSCs and ADSCs after melatonin preconditioning. Following melatonin preconditioning, BAX expression was significantly down-regulated in both ADSCs and BMSCs (P<0.05), with the difference being more significant in ADSCs compared to BMSCs. BCL2 expression was increased significantly in both cell types after preconditioning. Metalothionine 1 and Metalothionine 2 were both upregulated significantly in the two cell types (P<0.05). Melatonin increased osteogenesis capability through increasing osteocalcin expression. However, expression of osteocalcin in BMSCs before and after preconditioning was higher than that in ADSCs. On the other hand, melatonin expression in ADSCs was in higher levels than in BMSCs. Melatonin also improved alizarin red concentration significantly in both BMSCs and ADSCs (P<0.05). Alizarin red staining severity increased significantly in ADSCs after preconditioning compared to BMSCs (P<0.05). CONCLUSION: Here we have shown that the effects of preconditioning on melatonin expression in ADSCs are higher than those in BMSCs. These findings could be used in adoption of a proper preconditioning protocol based on the sources of MSCs in specific clinical applications, especially in bone regeneration.