Expression Of Bcl-2 In Tumor Cells Research Articles

PB2160: ASSOCIATION OF BCL-2 EXPRESSING TUMOR CELLS WITH RESPONSE TO FRONTLINE CHEMOTHERAPY IN NODULAR SCLEROSIS HODGKIN LYMPHOMA

Background: The BCL-2 protein belongs to the family of intracellular protein factors that control the processes of apoptosis. The process of regulation of programmed cell death depends on the balance between pro- and anti-apoptotic proteins of this family. In most cases, activation of BCL-2 helps suppress apoptosis and increase the lifespan of tumor cells, as well as increase their resistance to chemotherapy. The ability to block apoptosis is a hallmark of many malignant neoplasms, including hematological ones. Classical Hodgkin lymphoma (cHL) refers to a tumor of the hematopoietic system and has a relatively good response to treatment. However, in 15-20% of cases there is a lack of response to standard first-line chemotherapy. The data available in the relative literature regarding the relationship between BCL-2 expression in tumor cells and the effectiveness of treatment are contradictory. A number of authors confirms that the detection of this protein in Hodgkin and/or Reed-Sternberg cells (HRS) is an independent factor in the adverse outcome of cHL. But the inconsistency of the data indicates the advisability of further study of the association of the expression of the specified protein factor of apoptosis with the response to 1st line therapy. Aims: To study the relationship of BCL-2 expression with the response to frontline therapy in nodular sclerosis classical Hodgkin lymphoma (NSCHL). Methods: We used formalin-fixed paraffin-embedded (FFPE) lymph node samples of 37 patients with newly diagnosed NSCHL who were treated at the clinic of KRIHBT in the period from 2006 to 2018. Depending on the response to the 1st line therapy according to the BEACOPP-14 regimen, the subjects were divided into 2 groups: group 1 (n=17) included patients who achieved complete remission (CR). Group 2 (n=20) included patients with refractoriness to the first and subsequent lines of chemotherapy or minimal response to it, or patients who received autologous or allogeneic hematopoietic stem cell transplantation. To identify BCL-2+ tumor cells an immunohistochemical staining method was used. Pathomorphological analysis and relative number counting of BCL-2+ tumor cells were performed in sequential fields of view in 100 HRS cells for each sample. Results: According to the response to 1st-line chemotherapy, differences in the relative number of BCL-2+ tumor cells were established. In patients with a partial response (PR) to treatment, the number of positive cells was statistically significantly higher than in patients with CR: 80% (58-88) vs. 24% (8-42), respectively, p<0.001. The optimal threshold value for the proportion of BCL-2+ tumor cells was 46%. Based on the established threshold, all subjects were divided into two categories: with high (≥46%) and low (<46%) BCL-2 expression. Patients with a BCL-2+ cell count ≥46% are 18.4 and 59.5 times more likely to develop a PR and an adverse course, respectively, than those with a low threshold (p<0.05). The frequency of occurrence of BCL-2+ cells above the threshold level was detected statistically significantly more often in patients with frontline treatment failures of in relation to patients with CR: 17 (81%) versus 4 (19%) patients (p<0.001). Summary/Conclusion: A high relative content of BCL-2+ tumor cells (≥46%) is associated with treatment failures in patients with NSCHL. Determining the proportion of neoplastic cells marked with this antibody could be used as an additional morphological criterion for predicting the course of the disease already at the stage of diagnosing patients in order to apply a personalized approach to therapy with BCL-2 inhibitors.

Diagnostic value of CD10 and Bcl2 expression in distinguishing cutaneous basal cell carcinoma from squamous cell carcinoma and seborrheic keratosis

The distinction between cutaneous basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and seborrheic keratosis (SK), which are common entities in clinical practice, can be difficult clinically and histologically. CD10 and Bcl2 antigens are important factors in tumor growth, survival and spread. The aim of the present study is to define the frequency of CD10 and Bcl2 expression in such cutaneous tumors and its relation to the clinicopathological characteristics as well as their possible diagnostic utility. CD10 and Bcl2 immunohistochemistry was performed on 30 BCC, 20 SCC and 15 SK. 93.3% of SK cases and 53.3% of BCC cases showed significant expression of CD10 in tumor cells when compared either with each other or with SCC cases (100% negative). Stromal CD10 expression was positive in 50% of BCC cases and 75% of SCC cases. Stromal CD10 expression was significantly higher in high risk BCC and BCC with infiltrating deep margins; furthermore, it showed a significant positive correlation with grade of SCC. A significant inverse correlation between CD10 expression in stromal and tumor cells of BCC was present. Bcl2 was significantly expressed in 93.3% of SK cases and 80% of BCC cases when compared with SCC cases (100% negative). It was found that for distinguishing BCC from SK, only CD10 expression in tumor cells provided a high diagnostic value with positive likelihood ratio (PLR) was 7.00. In addition, CD10 and Bcl2 expression in tumor cells could give convincing diagnostic value to distinguish SCC from SK (PLR=15.00 for each marker). Moreover, for differentiating BCC from SCC, only Bcl2 in the tumor cells could provide a high diagnostic value (PLR=5.5). In conclusion, CD10 and Bcl2 can help in differentiating cutaneous BCC from SK and SCC. The overexpression of CD10 in the stromal cells of SCC and some variants of BCC suggests the invasive properties of such tumors.

Expression of Bax and Bcl-2 in Tumour Cells and Blood Vessels of Breast Cancer and their Association with Angiogenesis and Hormonal Receptors

A total of 96 cases of invasive breast ductal carcinoma were examined for immunohistochemical expression of Bax and Bcl-2 in the epithelial tumor cells and endothelial cells of the blood vessels. We also investigated the association between both proteins in the epithelium in relation to tumor characteristics such as tumor size, grade, lymph node involvement, microvessel density (MVD), hormonal receptors expression and c-erbB-2 overexpression. Bax expression showed a significant association between tumor and endothelial cells (p<0.001) while Bcl-2 expression in tumor cells was inversely associated with that in the endothelial cells (p<0.001). Expression of Bcl-2 in tumor cells was strongly associated with expression of estrogen and progesterone receptors (p=0.003 and p=0.004, respectively). In addition, intratumoral MVD was significantly higher than peritumoral MVD (p<0.001) but not associated with Bax or Bcl-2 expression and other tumor characteristics. We concluded that the number of endothelial cells undergoing apoptosis was in direct linkage with the number of apoptotic tumor cells. Anti-apoptotic activity of the surviving tumor cells appears to propagate cancer progression and this was influenced by the hormonal status of the cells. Tumor angiogenesis was especially promoted in the intratumoral region and angiogenesis was independent of anti-apoptotic activity.

Overexpression of SOX5 by a Novel Chromosome Translocation Involving the IGH Locus In a Follicular Lymphoma without BCL2 Expression

AbstractAbstract 4453The majority of follicular lymphoma (FL) cases are characterized by upregulation of BCL2 expression in tumor cells as results of a specific oncogenic event, t(14;18)(q32;q21), or other molecular mechanisms including amplification of the BCL2 gene. Approximately 10% of FL cases are lack of t(14;18)(q32;q21) and BCL2 expression. Molecular pathogenesis of BCL2 negative-FL has not been clarified.We found a case of BCL2-negative FL with a chromosome abnormalities including t(12;14)(p12;q32). Translocations involving 14q32 are frequently seen in B-lymphoid neoplasms, and breakpoints are often clustered within the IGH gene locus. Chromosome translocations involving the IGH locus represent the molecular mechanism of activation of a number of proto-oncogenes in B-cell neoplasms. In the present case, we hypothesized that as a result of the translocation a target gene on 12p12 is upregulated by juxtaposition to an enhancer region within the IGH gene and may play an important role in lymphoma development. Therefore, we attempted to determine a breakpoint of t(12;14)(p12;q32) by using a long-distance inverse PCR (LDI-PCR). Genomic DNA isolated from a lymph node sample was digested with restriction enzymes. Fragmented DNA was ligated to form circular DNA, and subjected to LDI-PCR. LDI-PCR was carried out using primer sets complementary to regions within the IGH locus. PCR products were subcloned into pGEM-T vector, and sequenced. The sequences were analyzed by a BLAST computational search. We determined the sequence around a breakpoint, in which we found the IGH gene J region on 14q32, as expected, and intron 1 of the SRY-related high-morbidity-group (HMG) box 5 (SOX5) gene on 12p12. In the rearranged chromosome region, an enhancer region within the IGH gene is located to up-stream of the exon 2 of the SOX5 gene. Coding region of the SOX5 genes spans from exons 5 to 20 so that all of coding exons of the SOX5 gene are retained on the rearranged chromosome. We examined SOX5 expression by immunohistochemistry using anti-SOX5 rabbit polyclonal antibody. SOX5 is overexpressed in nuclei of tumor cells in neoplastic follicle.SOX5 is a member of SOX family transcriptional factors which are characterized by the HMG box DNA binding domain. SOX5 is involved in the regulation of embryonic development and in the determination of the cell fate. In addition, SOX5 may play roles in the pathogenesis of some types of human cancers. In invasive testicular germ cell tumors, in which gain of short arm of chromosome 12 is frequently found, the SOX5 gene amplification is observed. In nasopharyngeal carcinoma, SOX5 overexpression is associated with poor clinical outcome, and SOX5 works as a transcriptional repressor for SPARC which is a putative tumor suppressor gene. These findings suggest that the SOX5 gene is a kind of proto-oncogene. Currently, Storlazzi et al. reported that SOX5 expression is upregulated by promoter swapping with the P2RY8 gene, as a result of t(X;12)(p22;p12) in primary splenic FL without BCL2 expression. Their report and our present result suggest that SOX5 overexpression play a role in BCL2-negative FL development. Further studies are necessary to clarify a molecular biological role of SOX5 overexpression in the pathogenesis of BCL2-negative FL. Disclosures:No relevant conflicts of interest to declare.

Targeted knockdown of Bcl2 in tumor cells using a synthetic TRAIL 3′‐UTR microRNA

Targeting tumor-related overexpression of anti-apoptotic Bcl2 protein by RNAi has been suggested as a potential treatment for cancer. However, the stability of RNAi and its delivery are still major obstacles to the clinical testing of Bcl2 RNAi. Here, we explore a novel strategy of expressing a synthetic Bcl2 microRNA (smRNA) in the 3' untranslated region (UTR) of the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), an apoptosis-inducing protein without apparent toxic effects in normal cells. TRAIL was specifically expressed from the human telomerase reverse transcriptase promoter (pTRT) that is active in many human tumors. Using this approach, we demonstrated that pTRT drove the tumor-specific expression of Bcl2 smRNA, which was processed by the host RNAi machinery and silenced endogenous Bcl2 expression in tumor cells. Bcl2 smRNA induced tumor cell apoptosis by activating caspase-3 and led to significant sensitization of tumor cells to TRAIL-induced apoptosis, while normal cells were spared. We also showed that the combined therapy of TRAIL-induced apoptosis and Bcl2 downregulation was superior to the mono-therapy of TRAIL or Bcl2 smRNA alone. This study proves a general paradigm for cancer therapy by using 3' UTR microRNA technology.

Role of Estrogen and Progesterone in the Survival of Ovarian Tumors — A Study of the Human Ovarian Adenocarcinoma Cell Line OC-117-VGH

The role of estrogen and progesterone in ovarian carcinogenesis and the growth and survival of ovarian cancer cells is controversial. In this study, we tested the effects of various concentrations of estrogen and progesterone on the survival of an ovarian cancer cell line. The ovarian adenocarcinoma cell line, OC-117-VGH, is deficient in the following receptors: estrogen receptor (ER)alpha, ERbeta, and progesterone receptor (PR). Serial concentrations of estrogen and progesterone were used to evaluate the effects of estrogen and progesterone on the survival of ovarian cancer cells. The apoptosis-related genes Bcl-2 and Bax were used to check the possible mechanism of an estrogen or progesterone effect on survival of the cancer cell line. Estrogen 0.01-1.0 microM and progesterone 0.1-10.0 microM affected cell survival. As predicted, progesterone successfully downregulated anti-apoptotic Bcl-2 expression, and dose-dependently suppressed Bcl-2 expression in tumor cells. Paradoxically, estrogen showed the same effects. In addition, both hormones downregulated proapoptotic Bax expression. The net effect confirmed the role of downregulated Bcl-2 in reducing the survival of ovarian cancer cells. Based on the findings of decreased survival and/or growth in OC-117-VGH ovarian adenocarcinoma cells treated with either estrogen or progesterone, we suspect that both hormones act effectively against ER-negative and PR-negative ovarian cancer cells. These findings should lead to a reassessment of hormone therapy for ovarian cancers.

Antisense oligonucleotides: promise and reality.

Antisense oligonucleotides have been used for more than a decade to downregulate gene expression. Phosphodiester oligonucleotides are nuclease sensitive, and the more nuclease-resistant phosphorothioate oligonucleotides are now in common use in the laboratory and have entered clinical trials. However, these molecules are highly bioactive and may inhibit gene expression by more than one mechanism. Although some dramatic successes have been demonstrated, it can still be difficult to properly interpret experimental data derived from the use of this class of oligonucleotide. This review discusses some of these issues with particular reference to a major area of current interest--inhibition of bcl-2 expression in tumor cells.

Analysis of Bcl-2 Protein Expression in Chronic Lymphocytic Leukemia

A number of studies revealed that high expression of the proto-oncogene bcl-2 correlated with poor prognosis or resistance to chemotherapy in some tumors but predicted a favorable clinical course in other neoplasias. In these studies, however, different immunologic techniques for Bcl-2 detection were used, raising the question of whether the methods applied were comparable. Using chronic lymphocytic leukemia (CLL) cells, the aims of our study were as follows: (1) to determine the reproducibility of Bcl-2 semiquantitation by immunocytochemistry, flow cytometry, or immunoblotting; (2) to study the agreement between results obtained by these methods; and (3) to examine the association between Bcl-2 expression in tumor cells of 99 patients with CLL and clinical parameters. We found that determination of Bcl-2 expression by immunocytochemistry was reproducible and the results were comparable with those of flow cytometry and immunoblotting. In the patient collective examined, Bcl-2 expression did not reflect the extent of tumor mass, but higher levels were found more often in patients with progressive disease.

Bcl-2 protein expression in astrocytomas in relation to patient survival and p53 gene status.

bcl-2 protein expression was characterized in a series of 58 astrocytomas from 21 pediatric and 37 adult patients. As part of a continuing attempt to define relevant prognostic factors which may predict clinical outcome, we have determined the impact of bcl-2 accumulation in malignant astrocytes on the length of patient survival. Aberrant overexpression of bcl-2 protein in tumor cells was detected in 57% (12 of 21) of pediatric and 73% (27 of 37) of the adult cases. Among pediatric patients, the median survival in months showed no relationship with the incidence of bcl-2-positive tumors. Among the adult patients, a favorable prognostic indicator was low-tumor grade (P = 0.05). bcl-2-positive tumors occurred with similar frequencies in WHO grades III and IV of malignancy. When bcl-2 expression in tumor cells was tested as a variable to predict for patient survival, the 6 patients without bcl-2 expression among 23 adult patients with grade IV tumors had a shorter median survival. The same 58 tumors had been previously analyzed for alterations of p53:4 pediatric and 16 adult tumors had p53 gene mutations. There was no significant difference in median survival related to p53 gene status. There was no relationship between bcl-2 expression and p53 gene status: approximately equal numbers of tumors with either wild-type or mutant p53 were bcl-2 negative or bcl-2 positive. bcl-2 expression is high (40-100%) among other tumors of the central nervous system which also show low malignant potential. Up-regulation of bcl-2 in malignant astrocytes or constitutive expression in some tumor types may be a factor leading to a more favorable clinical outcome.

皮膚Ｂ細胞性リンパ腫 Ｂｃｌ‐２発現に関する検討を加えて

皮膚Ｂ細胞性リンパ腫 Ｂｃｌ‐２発現に関する検討を加えて