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Morphine analgesia is mediated principally by the micro -opioid receptor (MOR). Since morphine and other opiates have been shown to influence glucose homeostasis, we investigated the hypothesis of direct cross talk between the MOR and the insulin receptor (IR) signaling cascades. We show that prolonged morphine exposure of cell lines expressing endogenous or transfected MOR, IR, and the insulin substrate 1 (IRS-1) protein specifically desensitizes IR signaling to Akt and ERK cascades. Morphine caused serine phosphorylation of the IR and impaired the formation of the signaling complex among the IR, Shc, and Grb2. Morphine also resulted in IRS-1 phosphorylation at serine 612 and reduced tyrosine phosphorylation at the YMXM p85-binding motifs, weakening the association of the IRS-1/p85 phosphatidylinositol 3-kinase complex. However, the IRS-1/Grb2 complex was unaffected by chronic morphine treatment. These results suggest that morphine attenuates IR signaling to Akt by disrupting the IRS-1-p85 interaction but inhibits signaling to ERK by disruption of the complex among the IR, Shc, and Grb2. Finally, we show that systemic morphine induced IRS-1 phosphorylation at Ser612 in the hypothalamus and hippocampus of wild type, but not MOR knockout, mice. Our results demonstrate that opiates can inhibit insulin signaling through direct cross talk between the downstream signaling pathways of the MOR and the IR.

To study the BRCA1 mutations in eastern Chinese patients with early onset breast cancer and affected relatives, 41 patients' genomic DNA from peripheral mononuclear blood cells was studied by using single strand conformational polymorphism (SSCP) and DNA sequencing. The BRCA1 mutations were detected in the whole gene sequence. Three novel disease-causing mutations (c.582C>T, c.735C>T and c.2790delT) occurred in all the patients. Two occurred in the patients younger than 35 years old (9.1%) and one in the patients with affected relatives (5%). Additional sequence variants identified included a novel missense mutation of unknown significance and six polymorphisms. The prevalence of BRCA1 mutations in Chinese patients in Shanghai with early onset breast cancer is similar to that observed in western women, but the incidence of mutations in breast cancer patients in Shanghai with affected relatives isn't as high as that in western women., (Copyright 2003 Wiley-Liss, Inc.)

A novel and highly stereoselective tandem rearrangement-reduction reaction of 1-benzyloxy-2,3-epoxide, under the promotion of triethylaluminum (AlEt3), has been developed to construct a quaternary stereocenter and the hydroxymethyl attached to the carbon center in one-step.

Objective: To evaluate the clinical value of mutated p53 in the peripheral blood of breast cancer patients., Methods: Plasma DNA of 126 breast cancer patients and 92 healthy women was examined. DNA extraction from the tumor and tissue samples was performed by a nonorganic method. Plasma DNA was purified on Qiagen columns. PCR-SSCP analysis was performed to examine the point mutations in the conserved exons 5, 6, 7 and 8 of TP53., Results: The mean concentration of plasma DNA was 21 ng/ml in healthy women and 211 ng/ml in patients with breast cancer (P < 0.01). p53 mutations in the primary tumor were detected in 46 of 126 (36.5%) breast cancer patients. Of these 46 patients, 30 (65.1%) were also found to have p53 mutations in their plasma DNA. p53 mutation in plasma DNA was closely correlated with clinical stage, tumor size, lymph node (LN) metastasis and estrogen receptor status (P < 0.05). Survival of the patients with both primary tumor and plasma p53 mutations was the worst. Thirteen of the 22 (59.0%) patients with recurrence and/or metastasis had detectable p53 mutations in their plasma DNA., Conclusion: p53 mutations in plasma DNA may be a useful prognostic factor and an early marker of recurrence or distant metastasis in breast cancer.

Objective: To evaluate the feasibility of lymphoscintigraphy in sentinel lymph node biopsy of breast cancer., Method: Lymphoscintigraphy was performed after peritumoral or subdermal injection of radioactive colloid. Then, sentinel lymph node (SLN) biopsy guided by gamma detector probe was performed. Factors correlated with identification-detection rate were assessed., Results: Lymphatic drainage was present in preoperative lymphoscintigraphy in 88(93%) out of 95 patients, with 39 (44.3%) positive for lymphatic drainage other than in the axilla. A total of 91 (95.8%) patients had their SLN identified in the intraoperative procedure. The quality of lymphoscintigraphic image was closely related to SLN identification-detection rate in the intraoperative procedure (P = 0.025)., Conclusion: Sentinel lymph node outside the axilla can be detected by lymphoscintigraphy. The combination of lymphoscintigraphy and gamma detector probe for sentinel lymph node biopsy of breast cancer not only is acceptable but promising.

The role of asymmetric charge neutralization as a primary determinant of protein-induced DNA helical bending remains controversial. Electrophoretic phasing experiments have been conducted previously for peptides derived from the yeast basic leucine zipper (bZIP) transcription factor GCN4 bound to AP-1 sites in duplex DNA. Mutations altering the electrostatic character of amino acids close to the DNA backbone result in phase-dependent gel mobility changes, interpreted as evidence of DNA bending. However, alternate interpretations are possible. The effect of electrostatic interactions on DNA conformation has now been investigated further, using purified peptides having indistinguishable AP-1 DNA affinity. Two independent techniques have been employed: electrophoretic phasing and fluorescence resonance energy transfer (FRET). The phasing results imply DNA bending by bZIP charge variants, consistent with earlier findings. FRET studies yield the mean 5' end to 3' end distance of AP-1 DNA when free or bound to neutral or charged bZIP peptides. These distances were reduced in the charged variant complexes relative to those in the free duplex and the wild-type complex. Bending of the DNA helical axis is shown by molecular modeling to be the simplest interpretation of these results. The electrophoretic phasing and FRET results thus offer two mutually supportive lines of evidence for induced bending of the DNA helical axis due to asymmetric changes in charge density caused by the electrostatic character of the amino acids residing near the DNA backbone.

Objective: To evaluate the accuracy of sentinel lymph node biopsy (SLNB) to predict the axillary lymph node status in breast cancer patients and its clinical significance., Methods: Seventy patients with clinical TNM status T(1 - 2)N(0)M(0) underwent sentinel lymph node biopsy using Tc-99m sulfur colloid radiotracer and gamma probe, which was followed by standard axillary dissection. SLNB was compared with standard axillary dissection for its ability to reflect the final pathological status of the axillary nodes. The SLNs that were tumor negative in conventional HE staining were further evaluated using immunohistochemical stains for CK8, CK19 and KP-1 antibodies., Results: The sentinel lymph node (SLN) was successfully identified in 67 (95.7%) out of 70 patients. The number of sentinel nodes harvested ranged from 1 to 5 (average 1.6). The nonsentinel nodes ranged from 5 to 20 (average 12.3). Of the 67 patients, 29 (43.3%) had histologically positive axillary lymph nodes. SLN was positive in 24 patients with metastasis (35.8%), and in 7 patients without metastasis (10.4%). In 5 patients, SLN was negative for tumor with positive nodes. The accuracy of sentinel lymph node biopsy to predict the axillary lymph node status was 92.5% and the false negative rate was 7.5%. For tumors with diameter less than or equal to 2 cm, the accuracy was 100%. 65 SLNs that were negative for HE stain were also non-reactive to immunostain for CK8 and CK19 antibody., Conclusions: SLNB can accurately predict the axillary lymph node status in most of breast cancer patients. The accuracy is about 100% in patients with T(1) lesions. Immunohistochemical staining at the same level of HE stain can not increase the detection of lymph node micrometastasis.

Insulin receptor substrate 1 (IRS-1) plays an important role in the insulin signaling cascade. In vitro and in vivo studies from many investigators have suggested that lowering of IRS-1 cellular levels may be a mechanism of disordered insulin action (so-called insulin resistance). We previously reported that the protein levels of IRS-1 were selectively regulated by a proteasome degradation pathway in CHO/IR/IRS-1 cells and 3T3-L1 adipocytes during prolonged insulin exposure, whereas IRS-2 was unaffected. We have now studied the signaling events that are involved in activation of the IRS-1 proteasome degradation pathway. Additionally, we have addressed structural elements in IRS-1 versus IRS-2 that are required for its specific proteasome degradation. Using ts20 cells, which express a temperature-sensitive mutant of ubiquitin-activating enzyme E1, ubiquitination of IRS-1 was shown to be a prerequisite for insulin-induced IRS-1 proteasome degradation. Using IRS-1/IRS-2 chimeric proteins, the N-terminal region of IRS-1 including the PH and PTB domains was identified as essential for targeting IRS-1 to the ubiquitin-proteasome degradation pathway. Activation of phosphatidylinositol 3-kinase is necessary but not sufficient for activating and sustaining the IRS-1 ubiquitin-proteasome degradation pathway. In contrast, activation of mTOR is not required for IRS-1 degradation in CHO/IR cells. Thus, our data provide insight into the molecular mechanism of insulin-induced activation of the IRS-1 ubiquitin-proteasome degradation pathway.

Apoptosis and expression of apoptosis-regulating proteins, Bcl-2 and Bax, have been observed in human breast carcinomas. The authors investigated whether expression of Bcl-2 and Bax proteins and apoptotic index (AI) had significance in cases of primary breast cancer. The authors evaluated Bcl-2 and Bax immunoreactivity and AI in primary breast cancers with the ApopTag method in 91 breast cancer patients retrospectively with long-term follow-up (median 60 months). Bcl-2 expression was seen in 60 (65.9%) cases and Bax expression was observed in 59 (64.8%) cases. Increased Bcl-2 and absence or low Bax immunoreactivity were significantly associated with low AI, high tumor grade, axillary lymph node involvement, postoperative recurrence, and metastasis. Thirty-five (38.5%) samples expressed high AI, which correlated with low tumor grade, absent axillary lymph node metastasis, and low levels of Bcl-2 with Bax overexpression. In univariate analysis, the variables associated with short relapse-free survival (RFS) and overall survival (OS) were large tumor size, axillary lymph node involvement, high histologic grade, low AI, high Bcl-2 expression, and absence or low Bax expression. In multivariate analysis, only Bcl-2 expression, lymph node status, and histologic grade were of independent prognostic value with respect to RFS and OS. Because the vast majority of the patients in this study received chemotherapy, it can be concluded that these apoptotic markers were also predictive of response to chemotherapy. Immunostaining of apoptosis-related genes, Bcl-2 and Bax, together with AI, may stratify high- versus low-risk breast cancer patients.