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Expression of Intratumoral IGF-II Is Regulated by the Gene Imprinting Status in Triple Negative Breast Cancer from Vietnamese Patients.

Radhakrishnan VK, Hernandez LC, Anderson K, Tan Q, De León M, De León DD - Int J Endocrinol (2015)

Bottom Line: Tumors with biallelic IGF-II gene expression exhibited the highest levels of proIGF-II and Survivin.Although 100% of these tissues corresponding normal samples were biallelic, they expressed significantly lower levels of or no proIGF-II and Survivin.Thus, IGF-II biallelic gene expression is differentially regulated in normal versus tumor tissues.

View Article: PubMed Central - PubMed

Affiliation: Center for Health Disparities and Molecular Medicine, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA.

ABSTRACT
African American women suffer higher incidence and mortality of triple negative breast cancer (TNBC) than Caucasian women. TNBC is very aggressive, causing the worst clinical outcome. We previously demonstrated that tumors from these patients express high IGF-II and exhibit high activation of the IGF signaling pathways. IGF-II gene expression is imprinted (monoallelic), promotes tumor progression, and metastasis and regulates Survivin, a TNBC prognostic marker. Since BC mortality has increased among young Vietnamese women, we analyzed 48 (paired) TNBC samples from Vietnamese patients to assess IGF-II expression. We analyzed all samples by qrtPCR for identification of IGF-II heterozygosity and to determine allelic expression of the IGF-II gene. We also analyzed the tissues for proIGF-II and Survivin by RT-PCR and Western blotting. A total of 28 samples displayed IGF-II heterozygosity of which 78% were biallelic. Tumors with biallelic IGF-II gene expression exhibited the highest levels of proIGF-II and Survivin. Although 100% of these tissues corresponding normal samples were biallelic, they expressed significantly lower levels of or no proIGF-II and Survivin. Thus, IGF-II biallelic gene expression is differentially regulated in normal versus tumor tissues. We propose that intratumoral proIGF-II is dependent on the IGF-II gene imprinting status and it will promote a more aggressive TNBC.

No MeSH data available.


Related in: MedlinePlus

(a) Representative bar graph of proIGF-II (17.5 kDa) in paired malignant and normal TNBC samples in Hom, Hom SNP, and Het. Figure depicts the averages of three separate experiments and each was done in triplicate. Heterozygous (N = 14, M = 13), Homozygous with SNP (N = 5, M = 6), and Homozygous (N = 5, M = 5). Asterisks indicate values statistically significant ∗(p < 0.05) using the Wilcoxon paired t-test. (b) Representative bar graph of Survivin (16.5 kDa) in paired malignant and normal TNBC samples in Hom, Hom SNP, and Het. Figure depicts the averages of three separate experiments and each was done in triplicate. Heterozygous (N = 14, M = 13), Homozygous with SNP (N = 5, M = 6), and Homozygous (N = 5, M = 5). Asterisks indicate values statistically significant ∗(p < 0.05) using the Wilcoxon paired t-test.
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fig5: (a) Representative bar graph of proIGF-II (17.5 kDa) in paired malignant and normal TNBC samples in Hom, Hom SNP, and Het. Figure depicts the averages of three separate experiments and each was done in triplicate. Heterozygous (N = 14, M = 13), Homozygous with SNP (N = 5, M = 6), and Homozygous (N = 5, M = 5). Asterisks indicate values statistically significant ∗(p < 0.05) using the Wilcoxon paired t-test. (b) Representative bar graph of Survivin (16.5 kDa) in paired malignant and normal TNBC samples in Hom, Hom SNP, and Het. Figure depicts the averages of three separate experiments and each was done in triplicate. Heterozygous (N = 14, M = 13), Homozygous with SNP (N = 5, M = 6), and Homozygous (N = 5, M = 5). Asterisks indicate values statistically significant ∗(p < 0.05) using the Wilcoxon paired t-test.

Mentions: We analyzed the levels of proIGF-II and Survivin protein in all 24 paired informative cases of TNBC by Western blot. Bands were revealed using chemiluminescence followed by exposure to radiography film. Relative protein quantification was determined by using QuantityOne 1-D Analysis Software and data is expressed as IDV proIGF-II and Survivin units/control IDV protein units from Ponceau red stain as seen in the y-axis in Figures 4(a), 4(b), 4(c), 5(a), and 5(b).


Expression of Intratumoral IGF-II Is Regulated by the Gene Imprinting Status in Triple Negative Breast Cancer from Vietnamese Patients.

Radhakrishnan VK, Hernandez LC, Anderson K, Tan Q, De León M, De León DD - Int J Endocrinol (2015)

(a) Representative bar graph of proIGF-II (17.5 kDa) in paired malignant and normal TNBC samples in Hom, Hom SNP, and Het. Figure depicts the averages of three separate experiments and each was done in triplicate. Heterozygous (N = 14, M = 13), Homozygous with SNP (N = 5, M = 6), and Homozygous (N = 5, M = 5). Asterisks indicate values statistically significant ∗(p < 0.05) using the Wilcoxon paired t-test. (b) Representative bar graph of Survivin (16.5 kDa) in paired malignant and normal TNBC samples in Hom, Hom SNP, and Het. Figure depicts the averages of three separate experiments and each was done in triplicate. Heterozygous (N = 14, M = 13), Homozygous with SNP (N = 5, M = 6), and Homozygous (N = 5, M = 5). Asterisks indicate values statistically significant ∗(p < 0.05) using the Wilcoxon paired t-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig5: (a) Representative bar graph of proIGF-II (17.5 kDa) in paired malignant and normal TNBC samples in Hom, Hom SNP, and Het. Figure depicts the averages of three separate experiments and each was done in triplicate. Heterozygous (N = 14, M = 13), Homozygous with SNP (N = 5, M = 6), and Homozygous (N = 5, M = 5). Asterisks indicate values statistically significant ∗(p < 0.05) using the Wilcoxon paired t-test. (b) Representative bar graph of Survivin (16.5 kDa) in paired malignant and normal TNBC samples in Hom, Hom SNP, and Het. Figure depicts the averages of three separate experiments and each was done in triplicate. Heterozygous (N = 14, M = 13), Homozygous with SNP (N = 5, M = 6), and Homozygous (N = 5, M = 5). Asterisks indicate values statistically significant ∗(p < 0.05) using the Wilcoxon paired t-test.
Mentions: We analyzed the levels of proIGF-II and Survivin protein in all 24 paired informative cases of TNBC by Western blot. Bands were revealed using chemiluminescence followed by exposure to radiography film. Relative protein quantification was determined by using QuantityOne 1-D Analysis Software and data is expressed as IDV proIGF-II and Survivin units/control IDV protein units from Ponceau red stain as seen in the y-axis in Figures 4(a), 4(b), 4(c), 5(a), and 5(b).

Bottom Line: Tumors with biallelic IGF-II gene expression exhibited the highest levels of proIGF-II and Survivin.Although 100% of these tissues corresponding normal samples were biallelic, they expressed significantly lower levels of or no proIGF-II and Survivin.Thus, IGF-II biallelic gene expression is differentially regulated in normal versus tumor tissues.

View Article: PubMed Central - PubMed

Affiliation: Center for Health Disparities and Molecular Medicine, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA.

ABSTRACT
African American women suffer higher incidence and mortality of triple negative breast cancer (TNBC) than Caucasian women. TNBC is very aggressive, causing the worst clinical outcome. We previously demonstrated that tumors from these patients express high IGF-II and exhibit high activation of the IGF signaling pathways. IGF-II gene expression is imprinted (monoallelic), promotes tumor progression, and metastasis and regulates Survivin, a TNBC prognostic marker. Since BC mortality has increased among young Vietnamese women, we analyzed 48 (paired) TNBC samples from Vietnamese patients to assess IGF-II expression. We analyzed all samples by qrtPCR for identification of IGF-II heterozygosity and to determine allelic expression of the IGF-II gene. We also analyzed the tissues for proIGF-II and Survivin by RT-PCR and Western blotting. A total of 28 samples displayed IGF-II heterozygosity of which 78% were biallelic. Tumors with biallelic IGF-II gene expression exhibited the highest levels of proIGF-II and Survivin. Although 100% of these tissues corresponding normal samples were biallelic, they expressed significantly lower levels of or no proIGF-II and Survivin. Thus, IGF-II biallelic gene expression is differentially regulated in normal versus tumor tissues. We propose that intratumoral proIGF-II is dependent on the IGF-II gene imprinting status and it will promote a more aggressive TNBC.

No MeSH data available.


Related in: MedlinePlus