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OBJECTIVE: The arginine- to-glutamine change at codon 3500 of the apolipoprotein B-100 (apo B) is a well- known genetic cause of hypercholesterolemia. Since increased cholesterol levels lead to atherosclerosis, identification of the carries of the apo B-3500 mutation is an important step in the risk stratification of individuals and families with hypercholesterolemia. The prevalence of this mutation in Turkish population is not well known. We aimed to investigate the frequency of apo B-100 mutations (codon 3500) C9774T (Arg 3500-->Trp) and G9775A (Arg 3500-->Gln) in patients with atherosclerosis in comparison with healthy subjects. METHODS: This cross-sectional study included 442 unrelated subjects living on the West coast of Turkey. Subgroups consisted of 165 patients with coronary artery disease, 163 patients with ischemic stroke, and 114 healthy control subjects. RESULTS: We did not find any apo B-100 mutation both in the patient and control groups. CONCLUSION: As it is hypothesized that this mutation arose within the Central European region from a common ancestor approximately 7000 years ago and spread across Europe, our result of the absence of the R3500Q mutation in Turkish patients give an important information about the geographical distribution of the apo B-R3500Q, that the mutation has not reached to Anatolia. [ABSTRACT FROM AUTHOR]

Background/aim: Glioblastoma is one of the most aggressive tumours, resistant to all applied therapy regiments and prone to relapse. Median survival rates are therefore only expressed as months. STING agonists are immunomodulatory molecules that activate type I interferon expression, making them potentially useful in regulating the tumour microenvironment. Since PTEN serves as a critical phosphatase in activating interferon-regulating transcription factors and is frequently mutated in glioblastoma cells, this study aimed to investigate STING activation in glioblastoma cell lines, examining whether they harbour the PTEN protein or not.°., Materials and Methods: T98G and U118MG glioblastoma cell lines were treated with the 2'3'-c-di-AM(PS)2(Rp,Rp) STING agonist together with or without the chemotherapeutic agent temozolomide. cGAS/STING pathway components were subsequently analysed using qRT-PCR, western blot, and ELISA methods., Results: Our results showed that PTEN-harbouring T98G cells responded well to STING activation, leading to increased temozolomide efficacy. In contrast, STING activation in U118MG cells did not affect the response to temozolomide. mRNA expression levels of STING , IRF3 , NF-KB , and RELA genes were significantly increased at the combined treatment groups in T98G cell line. Conversely, combined treatment with STING agonist and temozolomide did not affect mRNA expression levels of cGAS/STING pathway genes in U118MG cells., Conclusion: Our data offers new evidence suggesting that STING agonists can effectively be used to increase temozolomide response in the presence of PTEN protein. Therefore, increased GBM therapy success rates can be achieved by employing the PTEN expression status as a predictive biomarker before treating patients with a chemotherapeutic agent in combination with STING agonist., Competing Interests: Conflict of interest: The authors declare that they have no conflicts of interest., (© TÜBİTAK.)

Background: PTEN is a tumour suppressor gene and well-known for being frequently mutated in several cancer types. Loss of immunogenicity can also be attributed to PTEN loss, because of its role in establishing the tumour microenvironment. Therefore, this study aimed to represent the link between PTEN and cGAS-STING activity, a key mediator of inflammation, in tumour samples of glioblastoma patients., Methods: Tumour samples of 36 glioblastoma patients were collected. After DNA isolation, all coding regions of PTEN were sequenced and analysed. PTEN expression status was also evaluated by qRT-PCR, western blot, and immunohistochemical methods. Interferon-stimulated gene expressions, cGAMP activity, CD8 infiltration, and Granzyme B expression levels were determined especially for the evaluation of cGAS-STING activity and immunogenicity., Results: Mutant PTEN patients had significantly lower PTEN expression, both at mRNA and protein levels. Decreased STING, IRF3, NF-KB1, and RELA mRNA expressions were also found in patients with mutant PTEN. Immunohistochemistry staining of PTEN displayed expressional loss in 38.1% of the patients. Besides, patients with PTEN loss had considerably lower amounts of IFNB and IFIT2 mRNA expressions. Furthermore, CD8 infiltration, cGAMP, and Granzyme B levels were reduced in the PTEN loss group., Conclusion: This study reveals the immunosuppressive effects of PTEN loss in glioblastoma tumours via the cGAS-STING pathway. Therefore, determining the PTEN status in tumours is of great importance, like in situations when considering the treatment of glioblastoma patients with immunotherapeutic agents., (© 2024. The Author(s).)

Introduction: Fat graft survival has been studied numerously but has not gone beyond hypothetical solutions. The molecular changes in survival of standard fat grafts and enhanced survival by platelet-rich plasma (PRP) are compared in this study to reveal the etiology that causes the loss of fat grafts after transplantation., Materials and Methods: A New Zealand rabbit's inguinal fat pads were excised and divided into three groups: Sham, Control (C), and PRP. Each weighing 1 g, C and PRP fat were placed into the bilateral parascapular area of the rabbit. After 30 days, the remaining fat grafts were harvested and weighed (C = 0.7 g, PRP = 0.9 g). All three specimens were put into transcriptome analysis. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes Analysis were done to compare the genetic pathways between the specimens., Results: Transcriptome analysis showed similar differential expressions in Sham vs. PRP and Sham vs. C comparisons, indicating the dominance of the cellular immune response in both C and PRP specimens. C and PRP comparison resulted in inhibited migration and inflammation pathways in PRP., Conclusion: Fat graft survival is more related to immune responses than any other physiological process. PRP enhances survival by attenuating cellular immune reactions., Competing Interests: The authors have declared financial relationships, which are detailed in the next section., (Copyright © 2023, Yeğin et al.)

PTEN, a dual-phosphatase and scaffold protein, is one of the most commonly mutated tumour suppressor gene across various cancer types in human. The aim of this study therefore was to investigate the stability, structural and functional effects, and pathogenicity of 12 missense PTEN mutations (R15S, E18G, G36R, N49I, Y68H, I101T, C105F, D109N, V133I, C136Y, R173C and N276S) found by next generation sequencing of the PTEN gene in tissue samples obtained from glioblastoma patients. Computational tools and molecular dynamic simulation programs were used to identify the deleterious effects of these mutations. Furthermore, PTEN mRNA and protein expression levels were evaluated by qRT-PCR, Western Blot, and immunohistochemistry staining methods. Various computational tools predicted strong deleterious effects for the G36R, C105F, C136Y and N276S mutations. Molecular dynamic simulation revealed a significant decrease in protein stability for the Y68H and N276S mutations when compared with the wild type protein; whereas, C105F, D109N, V133I and R173C showed partial stability reduction. Significant residual fluctuations were observed in the R15S, N49I and C136Y mutations and radius of gyration graphs revealed the most compact structure for D109N and least for C136Y. In summary, our study is the first one to show the presence of PTEN E18G, N49I, D109N and N276S mutations in glioblastoma patients; where, D109N is neutral and N276S is a damaging and disease-associated mutation.Communicated by Ramaswamy H. Sarma.

Aims: Androgen receptor (AR) signaling is important in normal prostate and prostate tumor tissues. Thus, the new therapeutic strategies targeting ARs may also be important for treatment of prostate cancer (PC) and its biology. The studies have shown that miRNAs to be dysregulated in PC progression. Therefore, in the present study, differentially expressed miRNAs that predictively target the ARs were identified and investigated by in silico analysis., Main Methods: Cellular proliferation, qPCR, western blot and apoptosis assays were performed to investigate the molecular mechanism of the selected miRNAs in the PC cells., Key Findings: In our miRNA qPCR study, several miRNAs were found to be differentially regulated in castration resistant prostate cancer (CRPC) cells (LNCaP-Abl and LNCaP-104R2) compared with androgen dependent (AD) cells (LNCaP). The expression levels of miR-625-5p and miR-874-3p were significantly increased in LNCaP-Abl (2.62-fold, p = 0.0002; 4.00-fold, p = 0.00002, respectively) and LNCaP-104R2 (2.44-fold, p = 0.0455; 3.77-fold, p = 0.0383, respectively) compared with AD cells. The expression levels of AR and prostate specific antigen were increased in PC cells compared with AD cells. Furthermore, transfection of PC cells with anti-miRs suppressed their proliferation and AR protein levels (p < 0.05)., Significance: Several differentially regulated miRNAs were identified in CRPC cells, including miR-625-5p and miR-874-3p that are potentially involved in PC progression. These results may provide novel insights into the molecular mechanism underlying CRPC cells and miRNA applications may constitute a new and alternative method to prevent development of CRPC cells in the future., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Attention-Deficit/Hyperactivity Disorder (ADHD) is a phenotipically and neurobiologically heterogeneous disorder. Deficiencies at different levels in response inhibition, differences in dopamine transporter genotype (DAT1) and various symptomatic presentations contribute to ADHD heterogeneity. Integrating these three aspects into a functional neuroimaging research could help unreval specific neurobiological components of more phenotipically homogeneous groups of patients with ADHD. During the Go-NoGo trial, we investigated the effect of the DAT1 gene using 3 T MRI in 72 ADHD cases and 24 (TD) controls that typically developed between the ages 8 and 15 years. In the total ADHD group, DAT1 predicted homozygosity for the 10R allele and hypoactivation in the anterior cingulate cortex and paracingulate cortex. There were no significant activation differences between DAT1 10R/10R homozygotes and 9R carriers in TD controls. Subjects with predominantly inattentive ADHD (ADHD-I) presentation with DAT1 10R/10R homozygous reduced neuronal activation during Go trial particularly in the frontal regions and insular cortex, and in the parietal regions during NoGo trial (brain regions reported as part of Default Mode Network- DMN). Additionally, DAT1 10R/10R homozygousness was associated with increased occipital zone activation during only the Go trial in the ADHD combined presentation (ADHD-C) group. Our results point the three main findings: 1) The DAT1 gene is 10R homozygous for differentiated brain activation in ADHD cases but not in the TD controls, supporting the DAT1 gene as a potential marker for ADHD, 2) The relationship between the DAT1 gene and the occipital regions in ADHD-C group which may reflect compensatory mechanisms, 3) The relationship between DAT1 gene and the reduced DMN suppression for 9R carriers probabaly stems from the ADHD-I group.

Objective: Studies to reduce the heterogeneity of attention-deficit/hyperactivity disorder (ADHD) have increased interest in the concept of sluggish cognitive tempo (SCT). The aim of this study was to investigate if the prevalence of two variable-number tandem repeats (VNTRs) located within the 3'-untranslated region of the DAT1 gene and in exon 3 of the dopamine D4 receptor (DRD4) gene differ among four groups (31 subjects with SCT but no ADHD, 146 individuals with ADHD but no SCT, 67 subjects with SCT + ADHD, and 92 healthy controls)., Methods: We compared the sociodemographic profiles, neurocognitive domains, and prevalence of two VNTRs in SCT and ADHD subjects versus typically developing (TD) controls., Results: The SCT without ADHD group had a higher proportion of females and lower parental educational attainment. Subjects in this group performed worse on neuropsychological tests, except for psychomotor speed and commission errors, compared to controls. However, the ADHD without SCT group performed significantly worse on all neuropsychological domains than controls. We found that 4R homozygosity for the DRD4 gene was most prevalent in the ADHD without SCT group. The SCT without ADHD group had the highest 7R allele frequency, differing significantly from the ADHD without SCT group., Conclusion: The 7R allele of DRD4 gene was found to be significantly more prevalent in SCT cases than in ADHD cases. No substantial neuropsychological differences were found between SCT and ADHD subjects.

Purpose: We aimed to investigate the cisplatin-related hearing toxicity and its possible relationship with polymorphic variants in DNA repair genes, ERCC1, ERCC2, and XRCC1., Methods: Fifty patients treated with cisplatin in the past were included in the study. There were 29 females and 21 males; mean age 13.4 ± 6.0 years). The polymorphism in DNA repair genes was studied using primer and probes in Light Cycler device after DNA isolation was carried out with PCR technique. The polymorphisms and clinical risk factors were evaluated using Chi square test and logistic regression modelling., Results: The patients had hearing loss in 44%. For ERCC1 gene, the patients with hearing loss had 50% of GG (wild type), 40.9% of AG and 9.1% of AA genotypes, while the patients without hearing loss had 28.6% of GG, 53.5% of AG, and 17.9% of AA genotypes. For ERCC2 gene, the patients with hearing loss had 18.2% of GG (wild type), 40.9% of TG, and 40.9% of TT genotypes, while the patients without hearing loss had 10.7% of GG 39.3% of TG, and 50% of TT genotypes. For XRCC1 gene, the patients with hearing loss had 18.2% of CC (wild type), 59.1% of CT, and 22.7% of TT genotypes, while the patients without hearing loss had 35.7% of CC, 50% of CT, and 14.3% of TT genotypes. There was no statistically significant association among the groups (p = 0.24)., Conclusion: We did not find a relationship between DNA repair gene polymorphisms and hearing toxicity of cisplatin.

In the era of tyrosine kinase inhibitors, resistance still constitutes a problem in chronic myeloid leukemia (CML) patients; thus, new pathway-specific inhibitors like miRNAs have become important in the treatment of refractory patients. There are no satisfying data regarding the miRNAs and anti-miRNA treatment targeting STAT5A and 5B. In this study, we first researched the effect of dasatinib on apoptosis in the CML cell line K562. The expressions of miRNAs possibly targeting both STAT5A and 5B were then determined. The down- and upregulation of the miRNAs were compared using the ΔΔCT method. At the last stage of the study, we used a new primer probe in order to validate the results. The level of hsa-miR-940 was decreased 4.4 times and the levels of hsa-miR-527 and hsa-miR-518a-5p were increased 12.1 and 8 times, respectively, in the dasatinib-treated group when compared to the control group. We detected similar results in the validation step. As a conclusion, we determined the expression profiles of miRNAs targeting STAT5A and 5B that had an important role in the pathogenesis of CML. The data obtained could lead to determining new therapeutic targets for CML patients.

We aimed to determine the genotype distribution, allele frequency, and prognostic impact of IDH1/2, TET2, and ASXL1 single nucleotide polymorphisms (SNPs) in myeloproliferative neoplasms (MPNs). TET2 (rs763480), ASXL1 (rs2208131), and IDH1 (rs11554137) variant homozygous genotype frequencies were found at rates of 1.5%, 9.2%, and 2.3%, respectively. No IDH2 SNP was identified. IDH1 and TET2 frequencies were 5% in essential thrombocythemia (ET) and 1.7% in ET and 5% in primary myelofibrosis (PMF), respectively. ASXL1 frequencies were 8.3%-10% in MPN subgroups. The TET2 mutant allele T and ASXL1 mutant allele G had the highest frequencies with 0.272 in the PMF and 0.322 in the polycythemia vera (PV) group, respectively. There was no impact of the SNPs on prognosis. IDH1 frequency in MPNs was found similar to the literature. ASXL1 frequencies were similar between ET, PV, and PMF patients. The ASXL1 and TET2 allele frequencies of the Turkish population are similar to those of the European population. The role of SNPs in MPNs might be further evaluated in larger multicenter studies.

Objective: Methylphenidate is the first-choice medication for the Pervasive Developmental Disorders (PDDs), and comorbid Attention Deficit Hyperactivity Disorder (ADHD). But this approach generally results with poor outcomes, and increased adverse effects. It is aimed to investigate the comparison of cases who diagnosed with PDDs and Mild Mental Retardation (MR) and cases with pure ADHD in terms of the clinical response to MPH. Also we aimed to investigate the relations between CES-1 polymorphism gene and the clinical response to MPH., Methods: For clarifying this we searched for three polymorphisms (Arg199/His, Ser75/Asn, and Ile49/Val) in carboxylesterase-1 gene (CES-1) in the saliva of patients diagnosed with PDD+ADHD. Also, we assessed the clinical response to MPH by dimensional approach using the Attention Deficit Hyperactivity Disorder Rating Scale IV and Clinical Global Impression-Improvement scale., Results: PDD+ADHD groups had significantly higher Arg199/His polymorphism, and clinically responded poorer with symptoms sometimes even worsening to the MPH treatment compared with "pure" ADHD and ADHD+MR groups., Conclusion: This is the first study that an association between Arg199/His polymorphism in CES1 and altered treatment response to MPH in patients with PDD that presents with symptoms of ADHD.

This study aimed to provide novel insights into the white matter (WM) microstructural properties of Attention Deficit/Hyperactivity Disorder (ADHD) subtypes by recruiting a relatively large sample of stimulant-naïve children and adolescents who had no comorbidity other than Oppositional Defiant Disorder and were homogenous according to the DAT1 gene polymorphism. A sample of 72 ADHD subjects and 24 controls aged 8-15 years were enrolled in the study. We applied tract-based spatial statistics to the DTI measures for obtaining fractional anisotropy (FA) and axial, radial diffusivity (AD, RD) measures to explore ADHD type-related differences in WM for the whole brain. Comparing ADHD-Combined group (ADHD-C) with the ADHD predominantly inattentive group (ADHD-I) we detected increased RD in several bilateral brain area and increased AD mostly in left side of the brain, including the body and splenium of the corpus callosum; the anterior and posteriors limbs of the internal capsule; the superior, anterior and posterior corona radiata; the posterior thalamic radiation; and the superior longitudinal fasciculus. Likewise, mostly in the overlapping brain areas, the ADHD-C group presented increased AD values than ADHD-RI. Significant differences among ADHD types could be a preliminary evidence that they have distinct microstructural properties. There were no significant differences in diffusivity between controls and both the ADHD group as whole or any ADHD subgroups., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

During the process of developing the DSM-5, a new phenotype of ADHD was proposed-the ADHD restrictive inattentive presentation (ADHD-RI), describing subjects with high endorsement of inattentive symptoms and a low level of hyperactivity. However, this phenotype was not included in the DSM-5 because of the lack of robust neurobiological data. We aimed to assess the specific neurobiological underpinnings of individuals presenting ADHD-RI. We compared a sample of 301 subjects (101 ADHD-Combined; 50 ADHD-RI; 50 ADHD predominantly inattentive type and 100 typically developing subjects) aged 8-15 years, using a complete neuropsychological battery, molecular genetic data (DRD4 and DAT1 most studied polymorphisms) and functional MRI during a Go-No/Go task. Subjects with ADHD-RI had a significantly different neuropsychological profile compared with the other groups, including lower psychomotor speeds, longer reaction times and the worst overall performance in the global neurocognitive index. The proportion of subjects with the presence of DRD4-7 repeat allele was significantly higher in ADHD-RI. The fMRI data suggested that more attention-related posterior brain regions (especially temporo-occipital areas) are activated in ADHD-RI during both Go and No-Go cues compared to TD controls and ADHD predominantly inattentive type. ADHD-RI may represent a different phenotype than other types of ADHD. In addition, our results suggest that reducing the phenotypic heterogeneity may aid in the search for the neurobiological underpinnings of ADHD.

Purpose: Previously, we observed reciprocal changes in TRPC1 and TRPC6 expression levels in aging rat aorta and A7r5, rat embryonic vascular smooth muscle cells. Furthermore, downregulation of TRPC1 significantly elevated store-operated Ca(2+) entry suggesting the regulatory role of TRPC1 in A7r5 cells. Since TRPC6 upregulation shown to be associated with cell proliferation, the purpose of our study was to investigate the functional consequences of TRPC1 ion channel downregulation by RNA interference in Huh7 human hepatocellular carcinoma cell line., Methods: Huh7 cells used in quantitative gene and protein expression as well as in functional analyses. To determine mRNA and protein levels, quantitative real-time RT-PCR and western blot analyses were performed, respectively. In functional analyses, real-time changes in proliferation, migration and intracellular Ca(2+) levels were monitored., Results: In shTRPC1-transfected Huh7 cells, TRPC1 mRNA and protein levels significantly decreased whereas store-operated Ca(2+) entry significantly elevated. TRPC1-silencing suppressed cell proliferation without affecting cell migration in real-time cellular analyses., Conclusion: These results suggest that TRPC1 may take part both in regulation of store-operated Ca(2+) entry and proliferation of hepatocellular carcinoma cells., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

Aberrant expression profiles of microRNAs (miRNAs) have been previously demonstrated for having essential roles in a wide range of cancer types including leukemia. Antiproliferative or proapoptotic effects of capsaicin have been reported in several cancers. We aimed to study miRNAs involved in the Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway in chronic myeloid leukemia cell model and the effects of the capsaicin treatment on cell proliferation and miRNA regulation. miR-520a-5p expression was extremely downregulated in capsaicin-treated cells. Repressing the level of miR-520a-5p by transient transfection with specific miRNA inhibitor oligonucleotides resulted in induced inhibition of proliferation in leukemic cells. According to bioinformatics analysis, STAT3 messenger RNA was predicted as a putative miR-520a-5p target; which was confirmed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) and Western blot analysis. Cell proliferation inhibition was enhanced upon knockdown of STAT3 by RNA interference applications, but when miR-520a-5p inhibitor was additionally transfected onto STAT3 silenced cells, cell viability was dramatically decreased in leukemia cells. Finally, we observed the effects of capsaicin following miR-520a-5p inhibitor transfection upon cell proliferation, apoptosis, and STAT3 expression levels. We determined that, downregulation of miR-520a-5p affected the proliferation inhibition enhanced by capsaicin and reduced STAT3 mRNA and protein expression levels and increased apoptotic cell number. In summary, miR-520a-5p displays a therapeutic effect by targeting STAT3 and impacting the anticancer effects of capsaicin; whereas capsaicin, potentially through the miR-520a-5p/STAT3 interaction, induces apoptosis and inhibits K562 leukemic cell proliferation with need of further investigation.

In the current study, we aimed to identify the cytotoxic and apoptotic effects of bortezomib (BOR) on human K562 chronic myelogenous leukemia cells and to evaluate the potential roles of Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway members STAT3, STAT5, and JAK2 on BOR-induced cell death of leukemic cells. Cell viability was assessed via trypan blue dye exclusion test, and cytotoxicity of the BOR-treated cells was conducted by 2,3-bis(2-methoxy-4-nitro-5-sulphophenyl)-2H-tetrazolium-5-carboxanilide inner salt (XTT) assay. The relative messenger RNA (mRNA) expression levels of STAT3, STAT5A, STAT5B, and JAK2 were analyzed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). On the other hand, their protein expression levels were detected by western blot method. The obtained results indicated that BOR treatment reduced cell viability and induced leukemic cell apoptosis in a dose- and time-dependent manner as compared to untreated control cells. While mRNA expression levels of STAT5A, STAT5B, and STAT3 were significantly reduced following BOR treatment when compared to untreated controls, it had no effect upon JAK2 mRNA expression. As for protein levels, STAT expressions were downregulated after BOR treatment especially at 72nd and 96th hours. Our results pointed out that BOR treatment had a significant potential of being an anticancer agent for chronic myelogenous leukemia therapy, and this effect could be due to the expressional downregulations of JAK/STAT pathway members.

Janus Kinase 2 (JAK2) gene single point mutations, which have been reported to be associated with myeloproliferative disorders, are usually detected through conventional methods such as melting curve assays, allele-specific and quantitative Polymerase Chain Reactions (PCRs). Herein, an electrochemical biosensor for the detection of a Guanine (G) to Thymine (T) transversion at nucleotide position 1849 of the JAK2 gene was reported. Due to clinical importance of this mutation, easy and sensitive tests are needed to be developed. Our aim was to design a biosensor system that is capable of detecting the mutation within less than 1h with high sensitivity. For these purposes, an electrochemical sensing system was developed based on detecting hybridization. Hybridization between probe and its target and discrimination of single point mutation was investigated by monitoring guanine oxidation signals observed at +1.0 V with Differential Pulse Voltammetry (DPV) by using synthetic oligonucleotides and Polymerase Chain Reaction (PCR) amplicons. Hybridization between probe and PCR amplicons was also determined with Electrochemical Impedance Spectroscopy (EIS). We successfully detect hybridization first in synthetic samples, and ultimately in real samples involving blood samples from patients as well as additional healthy controls. The limit of detection (S/N=3) was calculated as 44 pmol of target sequence in a 40-μl reaction volume in real samples., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Purpose: Increased activation of the JAK-STAT signaling pathway is frequently observed in several primary cancers as well as cancer cell lines. Thus, targeting JAK-STAT pathway components by different molecular-biologic approaches in the search for new anticancer therapies has become widespread and resulted in encouraging outcomes. In this study, the effects of chemically modified anti-STAT3 small interfering (si)RNAs on cell viability, proliferation and apoptosis of parental and cisplatin resistant non-small cell lung cancer (NSCLC) cells were investigated with the aim to provide a new therapeutic strategy for overcoming cisplatin resistance in lung cancer., Methods: The parental NSCLC cell line Calu1 and its cisplatin- resistant subline CR-Calu1 were used to study the effects of STAT3 suppression with chemically modified anti-STAT3 siRNAs. STAT3 gene and protein expressions were analyzed by real-time (RT) quantitative (q) PCR and Western blot, respectively. Apoptosis was evaluated by Caspase-3 activity and cell death assays., Results: STAT3 messenger (m)RNA and protein expression were significantly increased in CR-Calu1 cells and suppressing its expression with specific siRNAs increased the rate of apoptosis through Caspase-3 activation. STAT3 suppression also significantly increased cisplatin sensitivity of Calu1 and CR-Calu1 cells after transfection with STAT3 siRNAs., Conclusions: NSCLC cells could be sensitized to cisplatin by targeting STAT3 with chemically modified siRNAs together, a fact which was accompanied with increased apoptosis.