Biomedical subjects

Y Pang

Publications and source records attributed to Y Pang.

112 records · Page 7Linked to original sources

PubMedDate not supplied

Association of hyaluronidase and breast adenocarcinoma invasiveness.

Hyaluronic acid (HA) is a component of the extracellular matrix (ECM) that exists as a high molecular weight polymer composed of alternating disaccharides, D-glucuronic acid and N-acetyl D-glucosamine. The interaction of hyaluronidase with HA results in the disruption of basement membrane integrity and produces an angiogenic response that has been implicated in tumor invasiveness and metastasis. Although hyaluronidase is present in several neoplasms, levels of hyaluronidase expression in breast cancer are not known. This investigation defines the correlation of elevated levels of hyaluronidase with breast adenocarcinoma invasiveness. Utilizing RT-PCR, RNA was extracted from paraffin embedded tissues (n=6) of patients diagnosed with fibrocystic breast changes, ductal carcinoma in situ (DCIS), and invasive adenocarcinoma. After constructing cDNA primers for base pairs 504 and 759 of the PH-20 gene (which is homologous to the hyaluronidase gene), PCR was performed and the products were visualized with ethidium bromide using gel electrophoresis. Invasive breast adenocarcinoma had a significantly higher level of hyaluronidase expression compared to other breast tissue samples; (32+/-15 vs. 8+/-3; p<0.03). Elevated levels of hyaluronidase correlated with invasive breast adenocarcinoma. Our data suggests that elevated levels of hyaluronidase are associated with breast adenocarcinoma invasive potential. Hyaluronidase may play an integral role in breast cancer invasion and metastasis.

Adenocarcinoma↗

PubMedDate not supplied

Increased hyaluronidase expression in more aggressive prostate adenocarcinoma.

Tumor metastasis involves a complex sequence of cellular and biochemical events of which tumor cell penetration through the basement membrane is an essential component. Disruption of basement membrane integrity by hyaluronidase has been implicated in the development of locally advanced and metastatic carcinoma. This investigation correlates hyaluronidase expression with pathologic prognostic variables for prostate adenocarcinoma. Paraffin samples (n=9) of patients receiving prostatectomies for clinical stage B adenocarcinoma were evaluated. RT-PCR was utilized to detect the presence of hyaluronidase. These results were correlated with the histological assessment of each sample. Gleason score was significantly higher in patients with RT-PCR detectable hyaluronidase (mean +/- SD 7.25+/-1.8 versus 4.17+/-1.0; p<0.05). Histological evidence of perineural invasion was seen in 83% of the specimens with detectable hyaluronidase, whereas none was found in hyaluronidase negative samples (p<0.05). A trend was seen between hyaluronidase and capsular invasion with 33% hyaluronidase positive tumor exhibiting evidence of capsular invasion, while no evidence in the hyaluronidase negative tumor. These data suggest that hyaluronidase may be involved in prostate adenocarcinoma progression and metastasis.

Biomarkers, Tumor↗

PubMedDate not supplied

Insulin-like growth factor-I receptor antagonism results in increased cytotoxicity of breast cancer cells to doxorubicin and taxol.

Therapeutic strategies for patients with advanced-stage adenocarcinoma of the breast frequently include the use of cytotoxic chemotherapy. Insulin-like growth factor I (IGF-I) receptor, a key factor in cell-cycle regulation, is frequently overexpressed in high-grade breast cancers. IGF-I receptor overexpression in these tumors may provide a target for novel molecular therapy against this disease. Early passage samples of estrogen-responsive (ER+) MCF 7 and estrogen receptor-negative (ER-) MDA-231 cells were cultured in semi-confluent conditions. Dose-titrations were performed for doxorubicin and taxol with receptor modulation using IGF-I or a competitive receptor inhibitor, alphaIR3. The addition of 100 ng/ml IGF-I resulted in a >2-fold mitogenic response in both ER+ and ER- cells. Receptor activation prior to the treatment with cytotoxic chemotherapeutic agents altered the pattern of response with a 26.3% increase in IC50. Doxorubicin and taxol both produced dose-related toxicity with IC50 of 0.05 microg/ml and 0.00 microg/ml respectively. The addition of alphaIR3 resulted in increased cytotoxicity in IGF-I stimulated cells compared with the use of doxorubicin or taxol alone. These results suggest that IGF-I receptor modulation alters the response to cytotoxic chemotherapeutic agents in breast cancer cells.

Antibodies, Monoclonal↗

PubMedDate not supplied

[Molecular cloning and characterization of a novel WRKY gene from Brassica chinensis].

A new WRKY gene was cloned from Brassica chinensis by rapid amplification of cDNA ends (RACE). The full-length cDNA of BcWRKY was 1175 bp long and contained a 924 bp open reading frame (ORF) encoding a putative W-box-binding protein of 308 amino acids. The predicted BcWRKY protein was found to have a potential bipartite nuclear localization sequence (NLS-BP) in its N-terminal region followed by a WRKY DNA-binding domain. Bioinformatic analysis revealed that BcWRKY resembled other WRKY domain-containing proteins from Arabidopsis (AtWRKY18), tobacco (WIZZ), parsley (PcWRKY4) and wild oat (ABF2). Expression of the BcWRKY gene could be induced by salicylic acid (SA), and influenced by Pseudomonas syringae pv. tomato strain DC3000 infection and wounding treatment. Our study implies that BcWRKY might have similar functions possessed by other WRKY genes such as inducing the expression of some defense-related genes and increasing plant's disease resistance ability.

Amino Acid Sequence↗