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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

3% agarose gel showing ApaI restriction digestion of the 292 gDNA PCR products for the 48 breast normal (N) and malignant (M) samples. The IGF-II allelic pattern determined to be Heterozygous (Het; n = 27) displayed three bands of 292, 227, and 65 bp. The Homozygous with SNP (Hom SNP; n = 11) allelic pattern displayed two bands of 227 and 65 bp. Only one band (292 bp) is seen in the Homozygous without a SNP (Hom; n = 10) IGF-II allelic pattern. Symbols #, ∗, $, &, and @ represent paired samples from normal and malignant that were not next to each other's lane.
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fig1: 3% agarose gel showing ApaI restriction digestion of the 292 gDNA PCR products for the 48 breast normal (N) and malignant (M) samples. The IGF-II allelic pattern determined to be Heterozygous (Het; n = 27) displayed three bands of 292, 227, and 65 bp. The Homozygous with SNP (Hom SNP; n = 11) allelic pattern displayed two bands of 227 and 65 bp. Only one band (292 bp) is seen in the Homozygous without a SNP (Hom; n = 10) IGF-II allelic pattern. Symbols #, ∗, $, &, and @ represent paired samples from normal and malignant that were not next to each other's lane.

Mentions: Figure 1 shows a composite of 5 representative 3% agarose gels of all 48 TNBC samples. Symbols #, ∗, $, &, and @ were used to identify paired samples that were not loaded next to each other. The Heterozygous profile for IGF-II was identified by the presence of two polymorphic bands of 292 bp (undigested) and 227 bp + 65 bp if the IGF-II rs680 SNP is present (digested). The Homozygous profile without SNP was identified by the 292 bp single band and Homozygous with SNP yielded two fragments 227 bp + 65 bp, respectively. Samples were further identified by N (normal tissue) and M (malignant tissue). Thus, the gDNA analysis of all 48 TNBC samples resulted in samples characterized as Heterozygous (n = 27), Homozygous (n = 10), and Homozygous with a SNP (n = 11). Thus, approximately 58% of the samples were Het, 21% were Hom, and another 21% were Hom SNP. Therefore, approximately 80% of all samples express the IGF-II rs680 SNP. The parental origin of the SNP was not considered in these experiments since the parental blood samples were not available for analysis.


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)

3% agarose gel showing ApaI restriction digestion of the 292 gDNA PCR products for the 48 breast normal (N) and malignant (M) samples. The IGF-II allelic pattern determined to be Heterozygous (Het; n = 27) displayed three bands of 292, 227, and 65 bp. The Homozygous with SNP (Hom SNP; n = 11) allelic pattern displayed two bands of 227 and 65 bp. Only one band (292 bp) is seen in the Homozygous without a SNP (Hom; n = 10) IGF-II allelic pattern. Symbols #, ∗, $, &, and @ represent paired samples from normal and malignant that were not next to each other's lane.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4581569&req=5

fig1: 3% agarose gel showing ApaI restriction digestion of the 292 gDNA PCR products for the 48 breast normal (N) and malignant (M) samples. The IGF-II allelic pattern determined to be Heterozygous (Het; n = 27) displayed three bands of 292, 227, and 65 bp. The Homozygous with SNP (Hom SNP; n = 11) allelic pattern displayed two bands of 227 and 65 bp. Only one band (292 bp) is seen in the Homozygous without a SNP (Hom; n = 10) IGF-II allelic pattern. Symbols #, ∗, $, &, and @ represent paired samples from normal and malignant that were not next to each other's lane.
Mentions: Figure 1 shows a composite of 5 representative 3% agarose gels of all 48 TNBC samples. Symbols #, ∗, $, &, and @ were used to identify paired samples that were not loaded next to each other. The Heterozygous profile for IGF-II was identified by the presence of two polymorphic bands of 292 bp (undigested) and 227 bp + 65 bp if the IGF-II rs680 SNP is present (digested). The Homozygous profile without SNP was identified by the 292 bp single band and Homozygous with SNP yielded two fragments 227 bp + 65 bp, respectively. Samples were further identified by N (normal tissue) and M (malignant tissue). Thus, the gDNA analysis of all 48 TNBC samples resulted in samples characterized as Heterozygous (n = 27), Homozygous (n = 10), and Homozygous with a SNP (n = 11). Thus, approximately 58% of the samples were Het, 21% were Hom, and another 21% were Hom SNP. Therefore, approximately 80% of all samples express the IGF-II rs680 SNP. The parental origin of the SNP was not considered in these experiments since the parental blood samples were not available for analysis.

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