BAG-1 Expression Research Articles

Clinicopathologic significance of BAG1 and TIMP3 expression in colon carcinoma

To explore the expression of BAG1 and tissue inhibitor of metalloproteinase 3 (TIMP3) in colon carcinoma and their correlation and clinicopathologic significance. SABC immunohistochemistry was used to detect the expression of BAG1 and TIMP3 in 80 colon carcinoma tissues and 20 normal colonic mucosa. Positive rate of BAG1 in colon carcinoma tissue (80%) was notably higher compared to normal colonic mucosa (10%) (P < 0.05). However, no significant difference was observed in positive rate of TIMP3 in colon carcinoma tissue (43.75%) as compared with normal colonic mucosa (60%) (P > 0.05). Expression of BAG1 and TIMP3 was strongly associated with colon carcinoma differentiation, Duke's staging, lymph node metastasis and survival rate (P < 0.05), but not associated with gender and age. Moreover, BAG1 expression was not correlated with TIMP3. Our results suggest that over-expression of BAG1 or attenuated expression of TIMP3 may play an important role in genesis and development of colon carcinoma. The protein expression levels of BAG1 and TIMP3 are related to the malignant degree, infiltration and metastasis of colon carcinoma. BAG1 and TIMP3 might be new biological parameters in predicting invasion and metastasis of colon carcinoma.

Cytoplasmic localization of BAG-1 in leukoplakia and carcinoma of the tongue: correlation with p53 and c-erbB2 in carcinoma

The present study evaluated the clinical significance of BAG-1, an antiapoptotic protein, in leukoplakia and carcinoma of the tongue. BAG-1 expression was evaluated by immunohistochemistry in paraffin-embedded tissues of leukoplakia (n=25) and carcinoma of the tongue (n=61). Cytoplasmic expression was predominantly seen in 80% and 70% of patients with leukoplakia and carcinoma, respectively. BAG-1 expression was found to be significantly lower in tobacco users than in non-tobacco users. BAG-1 expression in tobacco-using leukoplakia and carcinoma patients was compared by grouping the carcinoma patients according to lymph node status and disease stage. Carcinoma patients with tumor-positive lymph nodes had significantly lower BAG-1 expression than patients with negative lymph nodes and leukoplakia. Further, a trend towards an inverse correlation was observed with p53 and c-erbB2. In univariate and multivariate survival analysis, patient subgroups with 2+ or 3+ marker positivity (BAG-1 negativity, p53 and c-erbB2 positivity) had a reduced overall survival compared with patient subgroups with 1+ marker positivity or negativity. BAG-1 negativity in association with p53 and c-erbB2 positivity identified a subgroup of tongue cancer patients with an aggressive phenotype. Hence, an antiapoptotic protein, BAG-1, was found to be down-regulated in chewing-tobacco-mediated tongue carcinogenesis.

Immunohistochemical features of a papillary squamous cell carcinoma of the endometrium with transitional cell differentiation

An 84-year-old woman underwent hysterectomy due to a friable endometrial mass infiltrating almost half way through the myometrial wall. The tumor consisted of papillary structures with thin fibrovascular cores covered by several layers of pleomorphic cells. The deeply located neoplastic cells were ovoid with a pale eosinophilic cytoplasm resembling urothelial cells. A diagnosis of papillary squamous cell carcinoma of the endometrium with transitional cell differentiation was made. Although she recovered well after surgery, she died one year later because of disseminated disease. In an attempt to obtain new insights into the physiopathology of this very rare tumor, an immunohistochemical panel with 32 markers was performed. The neoplastic cells were positive for cytokeratin 5, vimentin, p63, p21, VEGF, Ki67, BAG1, and bcl-2. The expression of BAG-1 and bcl-2 may suggest that anti-apoptotic stimuli are preponderant in this neoplasm.

The growth compromised HSV-2 mutant ΔRR prevents kainic acid-induced apoptosis and loss of function in organotypic hippocampal cultures

We have previously shown that the HSV-2 anti-apoptotic protein ICP10PK is delivered by the replication incompetent virus mutant ΔRR and prevents kainic acid (KA)-induced epileptiform seizures and neuronal cell loss in the mouse and rat models of temporal lobe epilepsy. The present studies used ΔRR and the ICP10PK deleted virus mutant ΔPK to examine the mechanism of neuroprotection. ΔRR-infected neuronal cells expressed a chimeric protein in which ICP10PK is fused in frame to LacZ (p175) while retaining ICP10PK kinase activity. ΔPK-infected neuronal cells expressed a mutant ICP10 protein that is deleted in the PK domain and is kinase negative (p95). p175 and p95 were expressed in CA3 (86 ± 3%) and CA1 (69 ± 7%) cells from ΔRR or ΔPK-infected organotypic hippocampal cultures (OHC) and 80–85% of the ICP10 positive cells co-stained with antibody to β III Tubulin (neuronal marker). ΔRR, but not ΔPK, inhibited KA-induced cell death and caspase-3 activation in CA3 neurons, an inhibition seen whether ΔRR was delivered 2 days before or 2 days after KA administration (95% neuroprotection). Neuroprotection was associated with ERK and Akt activation and was abrogated by simultaneous treatment with the MEK (U0126) and PI3-K (LY294002) inhibitors. ΔRR-mediated neuroprotection was associated with increased expression of the anti-apoptotic protein Bag-1 and decreased expression of the pro-apoptotic protein Bad. The surviving neurons retained normal synaptic function potentially related to increased expression of the transcription factor CREB. The data indicate that ΔRR is a promising platform for neuroprotection from excitotoxic injury.

Fludarabine induces apoptosis in chronic lymphocytic leukemia - the role of P53, Bcl-2, Bax, Mcl-1, and Bag-1 proteins

The expression of P53, Bcl-2, Bax, Bag-1, and Mcl-1 proteins in CD5/CD20-positive B-chronic lymphocytic leukemia (B-CLL) cells from 30 typical CLL patients was evaluated before and after 48 h of incubation with 10(-6) M fludarabine using multiparametric flow cytometric analysis. Protein expression was correlated with annexin V expression, Rai modified clinical staging, lymphocyte doubling time, and previous treatment. Our main goal was to determine the predictive value of these proteins in CLL cells in terms of disease evolution. Bcl-2 expression decreased from a median fluorescence index (MFI) of 331.71 +/- 42.2 to 245.81 +/- 52.2 (P < 0.001) after fludarabine treatment, but there was no difference between viable cells (331.57 +/- 44.6 MFI) and apoptotic cells (331.71 +/- 42.2 MFI) before incubation (P = 0.859). Bax expression was higher in viable cells (156.24 +/- 32.2 MFI) than in apoptotic cells (133.56 +/- 35.7 MFI) before incubation, probably reflecting defective apoptosis in CLL (P = 0.001). Mcl-1 expression was increased in fludarabine-resistant cells and seemed to be a remarkable protein for the inhibition of the apoptotic process in CLL (from 233.59 +/- 29.8 to 252.04 +/- 35.5; P = 0.033). After fludarabine treatment, Bag-1 expression was increased in fludarabine-resistant cells (from 425.55 +/- 39.3 to 447.49 +/- 34.5 MFI, P = 0.012), and interestingly, this higher expression occurred in patients who had a short lymphocyte doubling time (P = 0.022). Therefore, we could assume that Bag-1 expression in such situation might identify CLL patients who will need treatment earlier.

Expression of BAG‐1 protein correlates with aggressive behavior of prostate cancers

Differences in tumor behavior, ranging from indolent to aggressive, create a need for novel prognostic biomarkers. BAG-1 is a co-chaperone that regulates the activity of Hsp70, Bcl-2, Raf-1, growth factor, and steroid receptors (e.g., the Androgen Receptor). Using immunohistochemical method, we explored BAG-1 expression in prostate cancers and its association with clinicopathological parameters. BAG-1 immunostaining was elevated in prostate cancer compared to normal prostatic epithelium. Higher nuclear BAG-1 in hormone-refractory (n = 34) compared to localized untreated tumors (n = 58) (P < 0.0001) suggested that upregulation of the nuclear isoform may contribute to disease progression. In 64 early-stage patients (T2N0M0) treated with external-beam irradiation, cytosolic BAG-1 correlated with higher pretreatment levels of serum Prostate specific antigen (P = 0.04) and shorter time to disease progression (P = 0.00004). Increased cytosolic and nuclear BAG-1 expression may denote more aggressive variants of prostate cancer.

In vitro effects of bovine dialyzable leukocyte extract (bDLE) in cancer cells

Bovine dialyzable leukocyte extract (bDLE) is a dialyzate of a heterogeneous mixture of low molecular weight substances released from disintegrated blood leukocytes or lymphoid tissue obtained from homogenized bovine spleen. The purpose of this study was to determine if bDLE had cytotoxic effects and modulated apoptosis gene expression in breast cancer cells. The MCF-7, BT-474, MDA-MB-453, A-427, Calu-1, U937 and L5178Y cancer cell lines and PBMC human cells were treated with bDLE (0-0.66 U/mL) for 72 h. The bDLE effect on cell growth proliferation was evaluated by MTT assay, and the MCF-7 was evaluated by ethidium bromide-acridine orange staining; total DNA was evaluated for DNA fragmentation, and total RNA was isolated for p53, bag-1, c-myc, bim, bax, bcl-2 and bad mRNA expression. The bDLE had dose-dependent cytotoxic effects and demonstrated an IC50 at a dosage of 0.06 U/mL (P<0.05). The bDLE did not affect the viability of normal human PBMC. The bDLE induced DNA fragmentation at doses of 0.06 and 0.13 U/mL in MCF-7 breast cancer cells. The bDLE induced cytotoxic effects and suppressed the p53, bag-1, c-myc, bax, bcl-2, and bad mRNA expression that influences apoptosis in MCF-7 breast cancer cells. Bim mRNA expression was not detected. This may open up interesting prospects for the treatment of human breast cancer.

Toxoplasma gondii: DNA vaccination with bradyzoite antigens induces protective immunity in mice against oral infection with parasite cysts

Infection of the host by Toxoplasma gondii leads to an acute systemic dissemination of tachyzoites, followed by a chronic phase, in which bradyzoites, enclosed in cysts, persist in the brain, the heart, and other tissues. Among putative vaccine candidates, the bradyzoite antigens BAG1 and MAG1 look promising since they are preferentially expressed during the chronic stage of the parasite. This work focused on studying the immunogenicity of bradyzoite antigens in a mouse model of chronic toxoplasmosis. A mixture of plasmids directing the cytoplasmic expression of MAG1 and BAG1 in mammalian cells was used to immunize mice. We show here that immunized mice developed, preferentially, specific anti-MAG1 and anti-BAG1 IgG2a subclass antibodies, indicating a shift towards a Th1-like response after DNA immunization. We then demonstrated that DNA immunization followed by challenge infection elicited effective protection in mice, suggesting that bradyzoite antigens should be considered in the design of vaccines against toxoplasmosis.

Estrogen receptor beta (ERβ) protein expression correlates with BAG-1 and prognosis in brain glial tumours

Estrogen receptor beta (ERbeta) is an important mediator of estrogen function in a variety of tissues. Its expression declines in breast, ovarian, prostatic and colon carcinomas as well as in astrocytic tumours. BAG-1 is a multifunctional protein with an important role in neoplasia and is possibly regulated by estrogen receptors. One of the direct targets of BAG-1 is HSP70. The purpose of this study was to analyse the expression pattern of these proteins in two distinct types of glial neoplasms, to investigate their possible correlation and probe their impact on prognosis. ERbeta, BAG-1 and HSP70 protein expression was monitored immunohistochemically in 66 cases of astrocytomas and 20 oligodendrogliomas. In astrocytic tumours low ERbeta expression correlated significantly with high grade (P < 0.001), higher expression of cytoplasmic BAG-1 (P < 0.001) and worse survival (log rank P = 0.02). Multivariate analysis revealed that ERbeta expression had a prognostic value for overall survival in these patients (Cox P = 0.03), which was not dependent on grade. There was also statistically significant association of BAG-1 nuclear expression with HSP70 cytoplasmic expression. Our results strengthen the hypothesis that ERbeta, BAG-1 and HSP70 play an important role in the pathogenesis and progression of glial neoplasms. Moreover, ERbeta expression in astrocytic tumors might be an important prognostic factor for survival.

Bag-1 Expression in Hyperplastic and Neoplastic Prostate Tissue: Is There Any Relationship with BCL-Related Proteins and Androgen Receptor Status?

To evaluate the function and distribution of BAG-1 protein in hyperplastic and neoplastic prostate tissue and establish the relationship between this protein and BCL-related proteins (BCL-2 and BAX), androgen receptor (AR) expression and chromogranin A. Twenty-eight prostatic adenocarcinomas and 16 prostate hyperplasias were included in this retrospective study. BAG-1, BCL-2, BAX, androgen receptor and chromogranin A immunostaining was performed by means of standard avidin-biotin peroxidase methods. The M30 antibody was used to identify preapoptotic and apoptotic cells. The immunohistochemical histological score (HSCORE) semiquantative system was used to evaluate immunohistochemical staining. Statistical analysis showed a significant difference in HSCOREs of BAX, M30 and AR between the carcinoma and hyperplasia groups. Carcinomas expressed higher HSCOREs of these markers than hyperplasias. There were significant differences in nuclear and cytoplasmic BAG-1 positivity between high and low-grade carcinomas. BAG-1 expression was higher in low-grade carcinomas. In the carcinoma group there was a positive correlation (Pearson) between BCL-2 and cytoplasmic/nuclear BAG-1. In the hyperplasia group there was a negative correlation between BAX and BCL-2, and between AR and M30. We also detected a positive correlation between AR and nuclear/cytoplasmic BAG-1 and between nuclear and cytoplasmic BAG-1 in hyperplasias. BAG-1 showed the same specific basal cell localization as BCL-2 in hyperplastic and normal glands. The BAG-1 protein showed a distinct distribution pattern in hyperplastic and neoplastic prostate. BAG-1 in association with BCL-2 inhibits apoptosis and may prolong the life of neoplastic cells and give them a chance to gain new oncogenic features in early carcinogenesis.

The Anti-Apoptotic, Glucocorticoid Receptor Cochaperone Protein BAG-1 Is a Long-Term Target for the Actions of Mood Stabilizers

Increasing data suggest that impairments of cellular plasticity/resilience underlie the pathophysiology of bipolar disorder. A series of microarray studies with validating criteria have recently revealed a common, novel target for the long-term actions of the structurally highly dissimilar mood stabilizers lithium and valproate: BAG-1 [BCL-2 (B-cell CLL/lymphoma 2)-associated athanogene]. Because BAG-1 attenuates glucocorticoid receptor (GR) nuclear translocation, activates ERK (extracellular signal-regulated kinase) MAP (mitogen-activated protein) kinases, and potentiates anti-apoptotic functions of BCL-2, extensive additional studies were undertaken. Chronic administration of both agents at therapeutic doses increased the expression of BAG-1 in rat hippocampus. Furthermore, these findings were validated at the protein level, and the effects were seen in a time frame consistent with therapeutic effects and were specific for mood stabilizers. Functional studies showed that either lithium or valproate, at therapeutically relevant levels, inhibited dexamethasone-induced GR nuclear translocation and inhibited GR transcriptional activity. Furthermore, small interfering RNA studies showed that these inhibitory effects on GR activity were mediated, at least in part, through BAG-1. The observation that BAG-1 inhibits glucocorticoid activation suggests that mood stabilizers may counteract the deleterious effects of hypercortisolemia seen in bipolar disorder by upregulating BAG-1. Additionally, these studies suggest that regulation of GR-mediated plasticity may play a role in the treatment of bipolar disorder and raise the possibility that agents affecting BAG-1 more directly may represent novel therapies for this devastating illness.

Expression levels of Rab2, a G protein, and Bag-1, a Bcl-2 binding protein are controlled by withdrawal of nicotine from cultured pheochromocytoma PC12 cells

We previously reported that nicotine withdrawal up-regulates transcription of some immediately early genes (IEGs), c-fos (Ichino et al., 1999) and egr1, nur77 (Ichino et al., 2002) in cultures of pheochromocytoma PC12 cells, which are of neuronal lineage. In the present study we aimed at further elucidating the effects of nicotine withdrawal on the expression of the genes downstream of IEGs. We examined the changes in the protein levels of 2 GTP-binding proteins, Rab2 (Ras-related protein) and Rac1. PC12 cells were cultured in the presence of nicotine for 24 hours, and then the nicotine was removed from the medium. The protein level of Rab2 was low in the presence of nicotine, but was rapidly increased after nicotine withdrawal. In contrast, that of Rac1 did not change after the withdrawal. Considering the neuroprotective effect of nicotine, we also examined the level of Bag-1 protein, which is a binding protein for Bcl-2, an anti-apoptotic factor, and found a slight increase in the gene expression of Bag-1 following nicotine withdrawal. Among 56-kDa, 50-kDa, and 36-kDa protein components of the Bag-1 protein complex, the levels of 56-kDa and 50-kDa proteins were not changed by the addition or withdrawal of nicotine; but the level of the 36-kDa protein, which had been increased in the presence of nicotine, was markedly decreased after nicotine withdrawal. The present results suggest that such changes may also occur in individuals during abstaining from smoking and be related to the withdrawal symptoms experienced after smokers stop smoking.

Nuclear BAG-1 expression inhibits apoptosis in colorectal adenoma-derived epithelial cells

BAG-1 is an anti-apoptotic protein that is frequently deregulated in a variety of malignancies including colorectal cancer. There are three isoforms: BAG-1L is located in the nucleus, BAG-1M and BAG-1S are located both in the nucleus and the cytoplasm. In colon cancer, the expression of nuclear BAG-1 is associated with poorer prognosis and is potentially a useful predictive factor for distant metastasis. However, the function of BAG-1 in colonic epithelial cells has not been studied. Having previously shown a predominant nuclear localisation of BAG-1 in adenoma-derived cell lines, we wanted to determine the function of nuclear BAG-1 in these non-tumourigenic cells, to identify whether nuclear BAG-1 was implicated in tumour progression in the colon. In the current report we established that nuclear BAG-1 inhibits apoptosis in a colorectal adenoma-derived cell line. We demonstrate that apoptosis induced by gamma-radiation or the vitamin D analogue EB1089 in the non-tumourigenic human colorectal adenoma-derived S/RG/C2 cell line, was preceded by a decrease in nuclear and an increase in cytoplasmic BAG-1 expression. This change in subcellular localisation of BAG-1 was due to the redistribution of the BAG-1M isoform. In addition, we have shown that the maintenance of high nuclear BAG-1 through enforced expression of the nuclear localised BAG-1L isoform enhanced cellular survival after gamma-radiation or exposure to EB1089. Furthermore the expression of cytoplasmic BAG-1S isoform fused with a nuclear localisation signal protected against gamma-radiation induced apoptosis. This demonstrates that nuclear localisation of the BAG-1 protein confers a survival advantage in colorectal adenoma-derived cells and that nuclear BAG-1 could potentially be an important survival factor in colorectal carcinogenesis.

BAG-1 associates with the polyglutamine-expanded huntingtin aggregates

Huntington's disease (HD) is characterised by the proteolytic production of N-terminal fragments of huntingtin containing polyglutamine repeats that forms intracellular ubiquitinated aggregates in the affected neurons. Using cellular and transgenic mice model of HD, we report here that BAG-1 co-immunoprecipitates with the polyglutamine-expanded truncated N-terminal huntingtin (tNhtt) and associates with their aggregates through its interaction with the chaperones Hsc70/Hsp70. We further demonstrate that the over expression of BAG-1 protects polyglutamine-expanded tNhtt induced cell death. Since, BAG-1 is essential for cell survival, its association with tNhtt aggregates might disrupt its normal function and thereby promote polyglutamine-expanded tNhtt-induced cell death.

BAG-1 haplo-insufficiency impairs lung tumorigenesis

BackgroundBAG-1 is a multifunctional co-chaperone of heat shock proteins (Hsc70/Hsp70) that is expressed in most cells. It interacts with Bcl-2 and Raf indicating that it might connect protein folding with other signaling pathways. Evidence that BAG-1 expression is frequently altered in human cancers, in particular in breast cancer, relative to normal cells has been put forward but the notion that overexpression of BAG-1 contributes to poor prognosis in tumorigenesis remains controversial.MethodsWe have evaluated the effect of BAG-1 heterozygosity in mice in a model of non-small-cell lung tumorigenesis with histological and molecular methods. We have generated mice heterozygous for BAG-1, carrying a BAG-1 null allele, that in addition express oncogenic, constitutively active C-Raf kinase (SP-C C-Raf BxB) in type II pneumocytes. SP-C C-Raf BxB mice develop multifocal adenomas early in adulthood.ResultsWe show that BAG-1 heterozygosity in mice impairs C-Raf oncogene-induced lung adenoma growth. Lung tumor initiation was reduced by half in BAG-1 heterozygous SP-C C-Raf BxB mice compared to their littermates. Tumor area was reduced by 75% in 4 month lungs of BAG-1 haploinsufficient mice compared to mice with two BAG-1 copies. Whereas BAG-1 heterozygosity did not affect the rate of cell proliferation or signaling through the mitogenic cascade in adenoma cells, it increased the rate of apoptosis.ConclusionReduced BAG-1 expression specifically targets tumor cells to apoptosis and impairs tumorigenesis. Our data implicate BAG-1 as a key player in oncogenic transformation by Raf and identify it as a potential molecular target for cancer treatment.

Bag-1 expression as a prognostic factor in tongue squamous cell carcinomas.

To investigate the prognostic significance of the antiapoptotic protein Bag-1. In addition, the relationship between Bag-1 expression, other apoptosis-related and proliferative parameters. Eighty-five randomly selected patients with T1 to T4 oral tongue squamous cell carcinomas (SCC) were studied. Sections from diagnostic, formalin-fixed, paraffin-embedded specimens were stained immunohistochemically to detect Bag-1 protein. Bag-1 expression correlated positively with apoptosis-related parameters such as Bcl-2 expression (P =.001) and proliferation-related parameters including Ki-67, mean argyrophilic nucleolar organizer regions (mAgNOR), and the percentage of AgNOR (pAgNOR) (P =.0117, P =.0257, and P =.0008, respectively). Correlation with Bag-1 expression and T classification (P =.0362), N classification (P =.0284), and clinical stage (P =.0117) was also found. In addition, Bag-1 expression was associated with the carbohydrate epitopes H-antigen and Le (P =.0004 and P =.0011, respectively). No correlation was found between Bag-1 expression and p53 accumulation, Bax expression, or apoptotic index (AI). However, a combined score of Bcl-2 and Bag-1 expression was inversely associated with AI (P =.046). Patients with tumors expressing high Bag-1 values had a shortened disease-specific survival time when compared with those with low Bag-1 values (P =.0017). A two-parameter combination between Bag-1 expression and Bax expression or AI, respectively, revealed an enhanced prognostic potential (P <.0001) when compared with single parameters. Correlation between Bag-1 expression and other biologic variables revealed that Bag-1 might be involved in several biologic processes including apoptosis and cell proliferation. The expression of Bag-1 protein, particularly in combination with Bax expression or AI, respectively, has prognostic value in oral tongue SCC.

Age-related expression patterns of Bag-1 and Bcl-2 in growth plate and articular chondrocytes.

Aging cartilage displays increased chondrocyte apoptosis and decreased responsiveness of chondrocytes to growth factors. The molecular mechanisms responsible for these changes have not been identified. Bag-1 is a Bcl-2-binding protein that promotes cell survival, interacts with a diverse group of cellular proteins, and may integrate multiple pathways involved in controlling cell survival, growth, and phenotype. Bcl-2 is important for maintaining chondrocyte phenotype and delaying terminal differentiation and apoptosis of chondrocytes. Comparatively little is known about the role of Bag-1 in cartilage. Here we show that both growth plate and articular chondrocytes in the mouse express the Bag-1 protein. In the growth plate, Bag-1 expression is prominent in the late proliferative and prehypertrophic chondrocytes, displaying a pattern similar to what has been reported for Bcl-2. Further, the expression of both Bcl-2 and Bag-1 declines with age in the articular cartilage. Growth assays demonstrate that knocking down Bag-1 expression causes a decrease in growth rate. These results suggest that Bag-1 is involved in the regulation of chondrocyte phenotype and cartilage aging.

Prognostic value of apoptosis in breast cancer (pT1-pT2). A TUNEL, p53, bcl-2, bag-1 and Bax immunohistochemical study.

Apoptosis or programmed cell death produces cells breaking into several fragments of nuclei, cytoplasm or both nuclei and cytoplasm, known as apoptotic bodies which can be visualized in haematoxylin-eosin staining. Some genes (promoters and suppressors) control this process and certain mutations may induce the expression of abnormal proteins, which can be detected by immunohistochemical staining. Apoptosis can be detected by the TUNEL method either identifying apoptotic bodies or cells at the initial stages of the fragmentation process. We have studied 186 cases of infiltrating ductal breast carcinoma, stages pT1-pT2, and analysed the prognostic significance of tumour recurrence and overall survival of apoptotic index (AI) through univariate and multivariate analysis. We have also studied the immunohistochemical protein expression of apoptosis promoter and suppressors gene (p53, nuclear expression; bcl-2 and Bax, cytoplasm expression; BAG-1, nuclear and cytoplasm expression). The results indicate prognostic significance of p53 and bcl-2 related to patient death and bcl-2 and tumour size to tumour recurrence, bcl-2 acting as a protector factor (apoptotic suppressor) in both situations. On the other hand, we have not found useful prognostic information of AI either to tumour recurrence or overall survival in univariate or multivariate studies. In this study, Bax expression does not provide a new prognostic role in breast carcinoma, although it contrasts to the bcl-2 action and accelerates death.

BAG-1 expression in normal and neoplastic endometrium

Objective. BAG-1 has anti-apoptotic actions and is known to bind BCL-2 and steroid receptors. High levels of BAG-1 have been implicated as a prognostic indicator in breast cancer. Whether this observation can be generalized to endometrial cancer remains unknown. Methods. IRB permission was obtained for use of human discarded tissue. Immunohistochemical analyses were performed on: proliferative endometrium (PEM, 6), secretory endometrium (SEM, 28), “low-grade” neoplastic lesions (complex atypical hyperplasia and grade 1 endometrial adenocarcinomas) (19), and “high-grade” cancers (grade 2 and 3 endometrial adenocarcinomas) (13). The level of total BAG-1 and its isoforms was evaluated by Western blot in lysates from Ishikawa cells (grade 1), MFE 296 cells (grade 2), and SK-UT 2 cells (grade 3). Results. The proportion of “high-grade” cancers with positive cytoplasmic staining for BAG-1 was higher than that of secretory endometrium ( P = 0.006). Additionally, the proportion of specimens with positive staining for nuclear BAG-1 expression was significantly higher among high-grade carcinoma specimens compared to secretory specimens ( P = 0.009). A high proportion (91%) of all specimens were positive for BCL-2, limiting the ability to subcategorize the other variables analyzed. There was no relationship between positive nuclear BAG-1 expression and either estrogen receptor (ER) or progesterone receptor (PR) expression. BAG-1 was expressed in the three cell lines evaluated and total BAG-1 level was not different among the different cell lines. Conclusion. BAG-1 is expressed in the endometrium. High-grade cancers stain more frequently than secretory endometrium for both cytoplasmic and nuclear BAG-1 expression, perhaps indicating an association between expression of BAG-1 and prognosis.

BAG-1 expression correlates with Bcl-2, p53, differentiation, estrogen and progesterone receptors in invasive breast carcinoma.

BAG-1, a recently identified anti-apoptotic protein, is overexpressed in the majority of invasive breast carcinomas. Overexpression of BAG-1 is important for both multi-step oncogenesis and resistance of cancer cells to apoptosis induced by DNA-damaging alkylating agents. BAG-1 protein species are localized differentially; nuclear expression may be associated with a shorter disease-free and overall survival in early stage breast cancer, while cytoplasmic expression has been associated with longer survival in non-small cell lung cancer. Growing evidence suggests that Bcl-2 and p53 are also involved in the oncogenesis of breast cancer. Since BAG-1 interacts with Bcl-2 and is upregulated by mutant p53 in vitro, it would be interesting to determine if their expressions are correlated with each other and with other clinical prognostic factors in invasive breast cancer. To address this question we conducted a large scale retrospective study of BAG-1, Bcl-2 and p53 in 185 breast cancer patients. Our study again showed that BAG-1 is overexpressed in the majority of breast cancer patients. In addition, it demonstrated that the expression of BAG-1 correlates with that of Bcl-2, p53, differentiation, estrogen and progesterone receptors. Our clinical study supports the preclinical finding of the interaction between BAG-1 and Bcl-2, p53 and estrogen and progesterone receptors. Further experiments to explore the prognostic and therapeutic role of BAG-1 in breast cancer are warranted.