Downregulation of lncRNA CCDC26 contributes to imatinib resistance in human gastrointestinal stromal tumors through IGF-1R upregulation

Imatinib is the first line of therapy for patients with metastatic or gastrointestinal stromal tumors (GIST). However, drug resistance limits the long-term effect of imatinib. Long non-coding RNAs (lncRNAs) are emerging as key players in regulating drug resistance in cancer. In this study, we investigated the association between lncRNA CCDC26 and IGF-1R in GIST and their involvement in drug resistance. Considering the key role of lncRNAs in drug resistance in cancer, we hypothesized that IGF-1R is regulated by lncRNAs. The expression of a series of reported drug resistance-related lncRNAs, including CCDC26, ARF, H19, NBR2, NEAT1, and HOTAIR, in GIST cells treated with imatinib H19 was examined at various time-points by qRT-PCR. Based on our results and published literature, CCDC26, a strongly down-regulated lncRNA following imatinib treatment, was chosen as our research target. GIST cells with high expression of CCDC26 were sensitive to imatinib treatment while knockdown of CCDC26 significantly increased the resistance to imatinib. Furthermore, we found that CCDC26 interacted with c-KIT by RNA pull down, and that CCDC26 knockdown up-regulated the expression of IGF-1R. Moreover, IGF-1R inhibition reversed CCDC26 knockdown-mediated imatinib resistance in GIST. These results indicated that treatments targeting CCDC26-IGF-1R axis would be useful in increasing sensitivity to imatinib in GIST.

Inhibitory Effect of High Concentration Insulin on K562 Cell Proliferation and Its Mechanism / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the inhibitory effect of high concentration insulin on K562 cell proliferation and its underlying mechanism.</p><p><b>METHODS</b>K562 cells were treated by different concentration of insulin and/or anti-IGF-1R antibody (IGF-1R-Ab), MTT assay and flow cytometry were used to detect the K562 cells proliferation and apoptosis, respectivety; Western blot was used to measure the expression and phosphorylation level of IGE-IR, Akt, Erk1/2 in K562 cells under the different concentration of insulin.</p><p><b>RESULTS</b>MTT assay showed that less than 40 mU/ml insulin could promote K562 cell proliferation, while high concentration (> 40 mU/ml) insulin has been shown to inhibit K562 cell proliferation; Flow cytometry showed that 40 mU/ml insulin suppressed K562 cell apoptosis (P < 0.05), while 200 mU/ml insulin could significantly induce K562 cell apoptosis (P < 0.01); 0.01 to 1.0 µg/ml IGF-1R-Ab has significantly enhanced the inhibitory and inducing effects of high concentration (> 40 mU/ml) of insulin on K562 cell proliferation and apoptosis respectively (r = 0.962, P < 0.001); Western blot showed that after K562 cells were treated with different concentrations of insulin ERK, and the p-ERK expression did not change significantly, after K562 cells were treated with 200 mU/ml insulin, the expression of IGF-1R and AKT also not were changed obviously, while the phosphorylation level of IGF-1R and AKT increased.</p><p><b>CONCLUSION</b>High concentration (>40 mU/ml) of insulin inhibits K562 cell proliferation and induces its apoptosis, and its mechanism may be related with the binding IGF-1R by insulin, competitively inhibiting the binding of IGF-1 and IGF-1R, the blocking the transduction of PI3K/AKT signal pathway.</p>

Association between the expression of IGF1R and estrogen receptor and efficacy of neoadjuvant chemotherapy in beast cancer patients / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To detect the expression of IGF1R and estrogen receptor, and to explore the relationship between their expression and the pathological complete response (pCR) rate of neoadjuvant chemotherapy (docetaxel plus epirubicin) in breast cancer patients.</p><p><b>METHODS</b>We selected 139 women with breast cancer who underwent neoadjuvant chemotherapy (docetaxel plus epirubicin), and detected the expression of IGF1R and estrogen receptor in the samples taken before chemotherapy by Immunohistochemistry. The association between their expression and pCR rate of neoadjuvant chemotherapy was analyzed.</p><p><b>RESULTS</b>Among the 139 cases, IGF1R was highly expressed in 45.3% (63/139) cases, and ER was positively expressed in 62.6% (87/139) cases. IGF1R was highly expressed in 54.0% (47/87) of the ER+ cases, significantly higher than that of ER- cases (30.8%, P<0.01). The overall pCR rate of all the 139 patients who received docetaxel plus epirubicin as neoadjuvant chemotherapy was 10.1% (14/139). The pCR rate was 19.2% (10/52) of the ER- patients and 4.6% (4/87) of the ER+ patients (P<0.05). The pCR rate was 10.5% (8/76) in the patients with low IGF1R expression and 9.5% (6/63) in the patients with high IGF1R expression (P>0.05). The patients with negative expression of ER and high expression of IGF1R showed the highest pCR rate (31.2%, P<0.01).</p><p><b>CONCLUSIONS</b>Breast cancer patients with negative expression of ER and high expression of IGF1R are more sensitive to neoadjuvant chemotherapy of docetaxel plus epirubicin, and their pCR rate is significantly higher than that of other patients.</p>

Association between polymorphisms of insulin-like growth factor receptor gene and susceptibility to non-small-cell lung cancer in Fujian Chinese / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To assess the association between polymorphisms of insulin-like growth factor receptor (IGF-1R and IGF-2R) and genetic susceptibility and non-small-cell lung cancer (NSCLC).</p><p><b>METHODS</b>A case-control study of 260 patients with NSCLC and 258 cancer-free subjects from Fujian was carried out. Genotypes of polymorphisms of IGF-1R +1013 and IGF-2R +1619 were determined by DNA sequencing and polymerase chain reaction-restrictive fragment length polymorphism.</p><p><b>RESULTS</b>(1) Significant differences in allele frequency and genotypes distribution of IGF-1R +1013 (G/A) were found between the two groups (P<0.05). On multivariate analysis after controlling age and gender, compared with GG genotype of the IGF-1R +1013 (G/A), the risk of lung cancer for individuals with GA genotype was increased by 0.80 times (95%CI: 1.24-2.59, P = 0.002), those with AA genotype was increased by 2.56 times (95%CI: 1.78-7.26, P = 0.000), and those with the polymorphic A variant (GA or AA) was increased by 0.98 times (95%CI: 1.39-2.83, P = 0.000). No significant differences in genotypic or allelic frequencies of IGF-2R +1619 (G/A) were found between the two groups (P> 0.05). (2) After stratification of the clinical status, the IGF-1R +1013 A allele increased the risk of lung squamous cell carcinoma (OR = 3.20, 95%CI: 1.75-5.84, P = 0.000), lung adenocarcinoma (OR = 1.55, 95%CI: 1.00-2.41, P = 0.049) and other types of lung cancer (OR = 1.96, 95% CI: 1.10-3.49, P = 0.023), but no association was found between the two SNPs and other clinical features. (3) IGF-1R +1013 (G/A) and IGF-2R +1619(G/A) polymorphisms showed a synergic effect (P = 0.003).</p><p><b>CONCLUSION</b>The common IGF-1R gene polymorphism G1013A may influence the risk of lung cancer. The polymorphisms of IGF-1R +1013 (G/A) and IGF-2R +1619 (G/A) have synergistic influence on the risk of lung cancer.</p>

Inhibition of cytohesin-1 by siRNA leads to reduced IGFR signaling in prostate cancer

To explore how cytohesin-1 (CYTH-1) small interfering RNA (siRNA) influences the insulin-like growth factor receptor (IGFR)-associated signal transduction in prostate cancer, we transfected human prostate cancer PC-3 cell lines with liposome-encapsulatedCYTH-1 siRNA in serum-free medium and exposed the cells to 100 nM IGF-1. The mRNA and protein levels of the signal molecules involved in the IGFR signaling pathways were determined by real-time PCR and detected by Western blotting. The relative mRNA levels of CYTH-1, c-Myc, cyclinD1 and IGF-1R (CYTH-1 siRNA group vs scrambled siRNA group) were 0.26 vs 0.97, 0.34 vs 1.06, 0.10 vs 0.95, and 0.27 vs 0.41 (P < 0.05 for all), respectively. The relative protein levels of CYTH-1, pIGF-1R, pIRS1, pAkt1, pErk1, c-Myc, and cyclinD1 (CYTH-1 siRNA group vsscrambled siRNA group) were 0.10 vs 1.00 (30 min), 0.10 vs 0.98 (30 min), 0.04 vs 0.50 (30 min), 0.10 vs 1.00 (30 min), 0.10 vs 1.00 (30 min), 0.13 vs 0.85 (5 h), and 0.08 vs 0.80 (7 h), respectively. The tyrosine kinase activity of IGF-1R was associated with CYTH-1. The proliferative activity of PC-3 cells transfected with CYTH-1 siRNA was significantly lower than that of cells transfected with scrambled siRNA at 48 h (40.5 vs87.6 percent, P < 0.05) and at 72 h (34.5 vs 93.5 percent, P < 0.05). In conclusion, the interference of siRNA with cytohesin-1 leads to reduced IGFR signaling in prostate cancer; therefore, CYTH-1 might serve as a new molecular target for the treatment of prostate cancer.

Biological & physiological aspects of action of insulin-like growth factor peptide family.

The insulin-like growth factor (IGF) is a complex system of peptide hormones (insulin-like growth factors of type 1 and 2, IGF-1 and IGF-2), cell surface receptors (insulin receptor, IR; insulin-like growth factor receptors of type 1 and 2, IGF-R1, IGF-R2) and circulating binding proteins (insulinlike growth factor binding proteins, IGF-BP 1-6). IGF-1 and -2 are mitogens that play a role in regulating cell proliferation, differentiation and apoptosis. Their effects are mediated through the IGF-R1 which initiates signaling cascades that result in regulation of a number of biological responses. IGF-R2, together with IGF-BPs is involved in binding, internalization and degradation of IGF-2. IGF proteins regulate cell proliferation in an interconnected action via autocrine, paracrine and endocrine regulatory mechanisms. Consequently, any perturbation in each level of the IGF signaling proteins has been shown to be implicated in development and progression of numerous cancer types. The most important single components in this processes are IGF ligands as well as IGF-R1 - when disturbed they act as oncogenes. It has been shown that: (i) high serum concentrations of IGF-1 and IGF-2 are associated with an increased risk of breast, prostate, colorectal and lung cancers; and (ii) IGF-R1 is commonly disturbed in many tumours (like gastric, lung, endometrial cancer) leading to a phenotype of anchorage-independent tumour growth. In contrast, IGF-R2 is considered to act as a tumour suppressor gene; it protects the cells from neoplastic impulses. Consistent with the IGFs autocrine/paracrine regulation of tumour growth, cancer treatment strategies interfering with IGF-R1 signaling have been developed, that may be useful in future diagnostic and therapeutic strategies.

Bloqueo del receptor del factor de crecimiento semejante a la insulina tipo I utilizando oligodeoxinucleótidos antisentido en cáncer de mama experimental / Type I insulin-like growth factor receptor antisense strategies in experimental breast cancer

We addressed the effect of targeting type I insulin-like growth factor receptor (IGF-IR), with antisense strategies in in vivo growth of breast cancer cells. We used C4HD tumors from an experimental model of hormonal carcinogenesis in which medroxyprogesterone acetate induced mammary adenocarcinomas in Balb/c mice. Intratumor or systemic administration of phosphorothiolated antisense oligodeoxynucleotides (AS[S]ODN) to IGF-IR mRNA resulted in a significant inhibition of C4HD tumor growth. The antitumor effect was specific since inhibition of tumor growth was dose-dependent and no effect was observed in mice treated with sense S[S]ODN. Tumors from AS[S]ODN-treated mice showed a decrease in IGF-IR expression and in insulin receptor substrate-1 tyrosine phosphorylation. Activation of PI-3K/Akt, p42/p44 MAPK and ErbB-2 was abolished in tumors treated with AS[S]ODN. Progesterone receptor expression or activity remained invariable. This is the first demonstration that breast cancer growth can be inhibited by direct in vivo administration of IGF-IR AS[S]ODN.

Evaluamos el efecto del bloqueo de la expresión del receptor del factor de crecimiento semejante a lainsulina tipo I (IGF-IR) sobre el crecimiento in vivo de cáncer de mama empleando una estrategia“antisentido”. Utilizamos el adenocarcinoma mamario murino progestágeno-dependiente C4HD. La administración intratumoral o sistémica de oligodeoxinucleótidos antisentido fosfotiolados al ARNm del IGF-IR (AS[S]ODN) inhibió el crecimiento tumoral. El efecto antitumoral fue específico debido a su dosis-dependencia y a la faltade efecto en ratones tratados con el S[S]ODN “sentido”. Los tumores obtenidos de ratones tratados con AS[S]ODN mostraron: disminución en la expresión de IGF-IR y en la fosforilación del sustrato del receptor de insulina-1, inhibición de la activación de PI-3K/Akt, p42/p44MAPK y ErbB-2, mientras que la expresión y activación del receptor de progesterona no se afectó. Es la primera demostración que el

Niveles plasmáticos de insulina en pacientes con cáncer de mama: su posible valor pronóstico / Insulin plasmatic level in patients with breast carcinoma, its possible pronostic value

La insulina, miembro de la familia de factores de crecimiento que incluyen al factor de crecimiento tipo insulina I (IGF-I) y II (IGF-II), presenta efectos mitogénicos sobre células epiteliales mamarias normales y malignas (Goodwin y col., 2002). Se postula que altos niveles de insulina permiten identificar mujeres con una mala evolución de su cáncer de mama, en quienes deberán aplicarse estrategias terapéuticas más efectivas. Se estudiaron 32 pacientes con cáncer de mama, de las cuales 18 presentaron carcinoma ductal invasor, incluidos 3 multifocales (56 por ciento), 6 carcinoma lobulillar infiltrante (19 por ciento), 3 carcinoma papilar (10 por ciento) y el resto otros tipos (15 por ciento). Dos pacientes (7 por ciento) presentan diabetes mellitus no-insulino dependiente. Los niveles de insulina plasmática en ayunas determinados por RIA (Insulin-CT kit) resultaron en: 18 pacientes (56 por ciento) con niveles normales (5,5 a 19,9 µUI/ml), el resto (44 por ciento) con insulinemias superiores al normal. La insulinemia plasmática en ayunas en voluntarias sanas resultó ser de 13,9ñ4,3 µUI/ml (n=10)...

Factores de crecimiento insulino símiles: estructura, bioactividad y métodos de ensayo / Insulin-like growth factors: structure, bioativity and methods of assay

El sistema de los factores de crecimiento insulino-símiles (IGF) se halla involucrado en diferentes aspectos de la regulación celular y tisular, como así también en el desarrollo y el crecimiento corporal. Este sistema depende de la interacción entre ligandos (IGF-I, IGF-II), receptores (Tipo I, Tipo II), proteínas ligadoras o transportadoras (IGFBP-1 a -6), y proteasas específicas para las IGFBPs. La acción de los IGFs se encuentra regulada por diferentes factores y estímulos, tales como la hormona de crecimiento, que actúan a diversos niveles. El desarrollo de nuevos métodos para analizar los diferentes componentes del sistema de los IGFs ha aportado elementos adicionales para la evaluación, diagnóstico y seguimiento de pacientes con alteraciones del crecimiento