Prognostic significance of bcl-2 expression in resected pN2 non-small cell lung cancer

Overview of the anticancer activity of withaferin A, an active constituent of the Indian ginseng Withania somnifera

Cancer is still considered a "hopeless case", besides all of the advancements in oncology research. On the other hand, the natural products, as effective lead molecules, have gained significant interest for research due to the absence of toxic and harmful side effects usually associated with conventional treatment methods. Medicinal properties of herbal plants are strongly evidenced in traditional medicine from ancient times. In the context above, withaferin A (WA) was identified as the active principle of the plant Withania somnifera, its molecule being reported to have excellent anticancer and tumour inhibition activities in various cell lines. Furthermore, the in silico approaches in the medicinal chemistry of WA revealed the biological targets and gave momentum for the research that leads to many amazing pharmacological activities of WA which are not yet explored. This includes a broad spectrum of anticancer actions manifested in different organs (breast, pancreas, colon), melanoma and B cell lymphoma, etc. This review is an extensive survey of the most recent anticancer studies reported for WA, along with its mechanism of action and details about its in vitro and/or in vivo behaviour.

BIK drives an aggressive breast cancer phenotype through sublethal apoptosis and predicts poor prognosis of ER-positive breast cancer

Apoptosis is fundamental to normal animal development and is the target for many anticancer therapies. Recent studies have explored the consequences of "failed apoptosis" where the apoptotic program is initiated but does not go to completion and does not cause cell death. Nevertheless, this failed apoptosis induces DNA double-strand breaks generating mutations that facilitate tumorigenesis. Whether failed apoptosis is relevant to clinical disease is unknown. BCL-2 interacting killer (BIK) is a stress-induced BH3-only protein that stimulates apoptosis in response to hormone and growth factor deprivation, hypoxia, and genomic stress. It was unclear whether BIK promotes or suppresses tumor survival within the context of breast cancer. We investigated this and show that BIK induces failed apoptosis with limited caspase activation and genomic damage in the absence of extensive cell death. Surviving cells acquire aggressive phenotypes characterized by enrichment of cancer stem-like cells, increased motility and increased clonogenic survival. Furthermore, by examining six independent cohorts of patients (total n = 969), we discovered that high BIK mRNA and protein levels predicted clinical relapse of Estrogen receptor (ER)-positive cancers, which account for almost 70% of all breast cancers diagnosed but had no predictive value for hormone receptor-negative (triple-negative) patients. Thus, this study identifies BIK as a biomarker for tumor recurrence of ER-positive patients and provides a potential mechanism whereby failed apoptosis contributes to cancer aggression.

A fate worse than death: apoptosis as an oncogenic process

Apoptotic cell death is widely considered a positive process that both prevents and treats cancer. Although undoubtedly having a beneficial role, paradoxically, apoptosis can also cause unwanted effects that may even promote cancer. In this Opinion article we highlight some of the ways by which apoptosis can exert oncogenic functions. We argue that fully understanding this dark side will be required to optimally engage apoptosis, thereby maximizing tumour cell kill while minimizing unwanted pro-tumorigenic effects.

Prognostic value of Bcl-2 expression in patients with non-small-cell lung cancer: a meta-analysis and systemic review

Objective

B-cell-lymphoma-2 (Bcl-2) is a proto-oncogene that plays an important role in the regulation of apoptosis and cell survival. However, there are much conflicting data in the literature concerning the association between Bcl-2 and prognosis in non-small-cell lung cancer (NSCLC). There is little in the way of meta-analysis focused on Bcl-2 and its effect on NSCLC prognosis. This study was performed to provide an assessment of whether expression levels of Bcl-2 are associated with prognosis in patients with NSCLC.

Materials and methods

We searched PubMed, the Cochrane Library, and China National Knowledge Infrastructure for all eligible studies. The combined hazard ratios (HRs) and their corresponding 95% confidence intervals (CIs) in terms of overall survival were evaluated.

Results

Fifty published studies including 6,863 patients with lung cancer were included in this meta-analysis. Overall, Bcl-2 was expressed in 33% of the NSCLC tumors studied. Our analysis indicates that NSCLC patients with Bcl-2-positive expression have a better prognosis than those with Bcl-2-negative expression in both Asian and non-Asian study populations (HR 0.79, 95% CI 0.72–0.87, P<0.00001). However, Bcl-2-positive expression seems to have no significant impact on survival of stage I NSCLC patients.

Conclusion

Our results indicated that Bcl-2 might be a useful prognostic marker for NSCLC generally. Larger clinical trials are needed to confirm the prognostic value of Bcl-2 in stage I NSCLC.

Reasons for cancer metastasis: A holistic perspective

Over several years, scientists investigating cancer have focused their efforts on elucidating the mechanisms underlying cancer metastasis, with the aim of finding a way to inhibit this process. These mechanisms, however, only explain the process of cancer metastasis, but do not explain why cancer would metastasize in the first place. Cancer metastasizes due to several factors, namely attack by the immune system, lack of oxygen and necessary nutrients, large amounts of lactic acid produced by glycolysis and increased cell death. Therefore, the majority of the presently available treatments for cancer also bear the potential to induce metastasis. Thus, it is crucial in medical practice to minimize the risk of cancer metastasis during a time when there are no effective means to inhibit this process.

High expression of Bcl-2 protein predicts favorable outcome in non-small cell lung cancer: evidence from a systematic review and meta-analysis

BACKGROUND

The prognostic value of Bcl-2 protein expression in non-small cell lung cancer (NSCLC) is under debate. We therefore systematically reviewed the evidence for Bcl-2 protein effects on NSCLC survival to elucidate this issue.

MATERIALS AND METHODS

An electronic search in Pubmed and Embase complemented by manual searches in article references were conducted to identify eligible studies to evaluate the association between Bcl-2 protein expression and overall survival (OS) as well as disease free survival (DFS) of NSCLC patients. Combined hazard ratios (HRs) with corresponding 95% confidence intervals (95%CIs) were pooled using the random-effects model.

RESULTS

A total of 50 trials (including 52 cohorts) encompassing 7,765 patients were pooled in the meta-analysis regarding Bcl-2 expression and OS of NSCLC patients. High expression of Bcl-2 protein had a favorable impact (HR=0.76, 95%CI=0.67-0.86). In the group of Bcl-2 expression and DFS, 11 studies including 2,634 patients were included. The synthesized result indicated high expression of Bcl-2 protein might predict good DFS (HR=0.85, 95%CI=0.75-0.95).

CONCLUSIONS

Our present meta-analysis demonstrated favorable prognostic values of Bcl-2 expression in patients with NSCLC. Further prospective trails are welcomed to validate the utility of assessing Bcl-2 in NSCLC patient management.

MTA1--a stress response protein: a master regulator of gene expression and cancer cell behavior

Gene mutation's role in initiating carcinogenesis has been controversial, but it is consensually accepted that both carcinogenesis and cancer metastasis are gene-regulated processes. MTA1, a metastasis-associated protein, has been extensively researched, especially regarding its role in cancer metastasis. In this review, I try to elucidate MTA1's role in both carcinogenesis and metastasis from a different angle. I propose that MTA1 is a stress response protein that is upregulated in various stress-related situations such as heat shock, hypoxia, and ironic radiation. Cancer cells are mostly living in a stressful environment of hypoxia, lack of nutrition, and immune reaction attacks. To cope with all these stresses, MTA1 expression is upregulated, plays a role of master regulator of gene expression, and helps cancer cells to survive and migrate out of their original dwelling.

Resistance to apoptosis should not be taken as a hallmark of cancer

In the research community, resistance to apoptosis is often considered a hallmark of cancer. However, pathologists who diagnose cancer via microscope often see the opposite. Indeed, increased apoptosis and mitosis are usually observed simultaneously in cancerous lesions. Studies have shown that increased apoptosis is associated with cancer aggressiveness and poor clinical outcome. Furthermore, overexpression of Bcl-2, an antiapoptotic protein, is linked with better survival of cancer patients. Conversely, Bax, CD95, Caspase-3, and other apoptosis-inducing proteins have been found to promote carcinogenesis. This notion of the role of apoptosis in cancer is not new; cancer cells were found to be short-lived 88 years ago. Given these observations, resistance to apoptosis should not be considered a hallmark of cancer.

Apoptosis drives cancer cells proliferate and metastasize

Cancer has been considered to be the result of accumulated gene mutations, which result in uncontrolled cell proliferations for a long time. Cancers are also regarded to be capable of immune evasion. Furthermore, resistance to apoptosis was recognized as an important trait of cancer in the last score of years. However, there are numerous paradoxical issues in this whole set of theory. For example, there is no known set of genes of which mutations are responsible for human cancers. As for the trait of ‘resistance to apoptosis’, the fact is that cancer has increased frequency of apoptosis. The more malignant the tumour is, the more apoptosis shows. In this study, we propose a new theory that apoptosis plays a key role in the malignant progression and metastasis of cancer. The growth of tumour is the difference between tumour cell proliferation and attrition plus the hyperplastic growth of stroma. Increased and unpreventable death caused by innate or environmental factors such as ischaemia and inflammation drives the tumour cells to proliferate relentlessly, move to new lands to establish colonies. In short, increased cell death is the origin of malignancy.

Prognostic significance of micropapillary pattern in lung adenocarcinoma and expression of apoptosis-related markers: caspase-3, bcl-2, and p53

We evaluated the clinicopathological characteristics and prognostic significance of lung adenocarcinoma with micropapillary pattern (MPP) and analyzed the expression of apoptosis-related markers: caspase-3, bcl-2, and p53. A series of 166 lung adenocarcinoma that had been surgically resected between 2004 and 2009 were reviewed. Histopathologic patterns, presence of tumor necrosis, mitosis, lymphovascular and perineural invasion, the status of pleura, and tumor differentiation were examined. Of the 166 patients; 71 were stage I, 35 stage II, 51 stage III, and nine stage IV. Histologically they were divided into two groups: MPP-positive (n = 55) and MPP-negative (n = 111). The following items were significantly more frequent in the MPP positive group: female gender (p = 0.03), lymph node metastasis (p = 0.031), and pleural invasion (p = 0.045). Age, smoking status, tumor stage, lymphatic invasion, perineural invasion, mitotic count, and survival rates had no statistically significant difference between groups (p > 0.05). In MPP positive tumors, visceral pleural invasion was identified significantly more frequent than in MPP negative tumors, at stage I. Tumors with MPP showed elevated expressions of caspase-3 (94.5%), p53 (60%), and bcl-2 (54.5%). In MPP positive group, the expression of these three markers had no statistically significant impact on survival. In whole population, bcl-2 expression was correlated with a better outcome. We conclude that MPP is associated with poor prognostic factors both in early and late stages in lung adenocarcinoma. Bcl-2 provides prognostic information independent from the MPP.

High expression of BCL-2 predicts favorable outcome in non-small cell lung cancer patients with non squamous histology

Background

Bcl-2 promotes cell survival by inhibiting adapters needed for the activation and cleavage of caspases thus blocking the proteolytic cascade that ultimately dismantles the cell. Bcl-2 has been investigated as a prognostic factor in non small cell lung cancer (NSCLC) patients with conflicting results.

Methods

Here, we quantitatively assessed Bcl-2 expression in two large and independent cohorts to investigate the impact of Bcl-2 on survival. AQUA^®, a fluorescent-based method for analysis of in situ protein expression, was used to measure Bcl-2 protein levels and classify tumors by Bcl-2 expression in a cohort of 180 NSCLC patients. An independent cohort of 354 NSCLC patients was used to validate Bcl-2 classification and evaluate outcome.

Results

Fifty % and 52% of the cases were classified as high expressers in training and validation cohorts respectively. Squamous cell carcinomas were more likely to be high expressers compared to adenocarcinomas (63% vs. 45%, p = 0.002); Bcl-2 was not associated with other clinical or pathological characteristics. Survival analysis showed that patients with high BCL-2 expression had a longer median survival compared to low expressers (22 vs. 17.5 months, log rank p = 0.014) especially in the subset of non-squamous tumors (25 vs. 13.8 months, log rank p = 0.04). Multivariate analysis revealed an independent lower risk for all patients with Bcl-2 expressing tumors (HR = 0.53, 95% CI 0.37-0.75, p = 0.0003) and for patients with non-squamous tumors (HR = 0.5, 95% CI 0.31-0.81, p = 0.005).

Conclusions

Bcl-2 expression defines a subgroup of patients with a favorable outcome and may be useful for prognostic stratification of NSCLC patients.

Serum Vascular Endothelial Growth Factor (VEGF) and Bcl-2 Levels in Advanced Stage Non-Small Cell Lung Cancer

The characteristic changes in cancer process are assumed to be genetic alterations about the imbalance of cell proliferation and apoptotic cell death. This study was conducted to determine the value of the circulating vascular endothelial growth factor (VEGF) and Bcl-2 in patients with advanced stage non-small cell lung cancer (NSCLC). These serum factors were measured of 52 NSCLC patients pathologically verified on before and after chemotherapy in comparison with 16 healthy controls by using ELISA method. Both of the serum levels of VEGF (p = 0.015) and Bcl-2 (p < 0.001) were increased significantly in NSCLC patients compared with the healthy controls. No statistically significant relationships between investigated elevated serum parameters and various characteristics of patients and disease such as stage and tumor burden were determined. Likewise, we also found no correlation between serum VEGF and Bcl-2. Cytotoxic therapy of patients was accompanied by unchanged serum levels of serum factors. The median survival of all patients was 27 weeks and one-year survival rate was 22.4 percent. With the median serum levels as the cut-off value, patients were divided into high- and low-serum parameter groups. While we found that patients' performance status (p < 0.0001), serum LDH level (p = 0.0002), response to chemotherapy (p = 0.0023), and stage of the disease (p = 0.0085) were prognostic factors for survival, serum VEGF (p = 0.48) and Bcl-2 (p = 0.91) levels were determined as ineffective on survival in patients with advanced NSCLC. In conclusion, our data suggest that these serum factors, VEGF and Bcl-2, are useful diagnostic factors, not predictive and prognostic markers for overall survival in advanced NSCLC patients.

Prognostic implications of cell cycle-related proteins in primary resectable pathologic N2 nonsmall cell lung cancer

BACKGROUND

Patients who have pathologic N2 (pN2) nonsmall cell lung cancer (pN2 NSCLC) represent a heterogeneous group with regard to prognosis and treatment. Molecular features of NSCLC seem to be of interest. For the current study, to select an appropriate therapeutic strategy for each patient, patients with N2 NSCLC were stratified into homogenous subgroups according to the expression profiles of cell cycle-related markers.

METHODS

The expression levels of retinoblastoma protein (pRb), cyclin D1, p16, p53, and p21 proteins and values of the Ki-67 labeling index were evaluated in 61 primary surgically resected tumor specimens from patients with pN2 NSCLC using immunohistochemistry. The prognostic impact of these markers on overall survival was analyzed in both univariate and multivariate analyses.

RESULTS

In univariate analysis, p21, p16, and Ki-67 were correlated significantly with survival. In multivariate analysis, only p21 and p16 influenced survival. Indeed, the group of patients with pN2 NSCLC who were positive for p21 and p16 had the most favorable overall survival (P = .001) and were correlated significantly with the clinical lymph node (cN) status (cN2 disease; P = .008). Moreover, no significant difference in survival was observed between patients with cN0/cN1 disease and patients with cN2 disease within the group (P = .4333).

CONCLUSIONS

Loss of control of cell-cycle checkpoints is a common occurrence in pN2 NSCLC. Functional cooperation between different cell-cycle regulators constitutes another level of regulation in cell growth control and tumor suppression. Preoperative patients with pN2 NSCLC, even those with cN2 disease, who have positive p21 and p16 protein expression in their primary tumors are expected to have a favorable postoperative prognosis and may be candidates for primary resection.

Immunohistochemical markers of prognosis in non-small cell lung cancer: a review and proposal for a multiphase approach to marker evaluation

Characteristics of the tumour that affect and predict the survival outcome of patients with cancer are prognostic markers for cancer. In non-small cell lung carcinoma (NSCLC), stage is the main determinant of prognosis and the basis for deciding options for treatment. Patients with early-stage tumour are treated by complete surgical resection, which is curative in 40-70% of patients. That there are other factors important in determining the biology of these tumours, especially genes that have a role in metastasis, is indicated. Such factors could potentially be used to further classify patients into groups according to substages that may be treated differently. During the past decade, a large number of proteins that are putatively important in carcinogenesis and cancer biology have been studied for their prognostic value in NSCLC, but none of them have been proved to be sufficiently useful in clinical diagnosis. Several markers (epidermal growth factor receptor, human epidermal growth factor receptor 2, Ki-67, p53 and Bcl-2) have been studied exhaustively. Ki-67, p53 and Bcl-2 are suggested to be important but weak prognostic markers, by meta-analyses of the results. Cyclin E, vascular endothelial growth factor A, p16(INK4A), p27(kip1) and beta-catenin are promising candidates, but require further study in large randomised clinical trial samples by using standardised assays and scoring systems. Some issues and inconsistencies in the reported studies to date are highlighted and discussed. A guideline for a multi-phase approach for conducting future studies on prognostic immunohistochemistry markers is proposed here.

The expression of Bcl-2 family proteins differs between nonsmall cell lung carcinoma subtypes

BACKGROUND

Proteins of the Bcl-2 family play a key role in the control of apoptosis and carry out both proapoptotic and antiapoptotic functions. However, with the exception of Bcl-2 itself, little is known about the expression of these potentially critical proteins in nonsmall cell lung carcinoma.

METHODS

Immunohistochemistry was used to study the expression of Bcl-2 and 6 other Bcl-2 family proteins in a pilot series of 41 archival nonsmall cell lung carcinoma specimens (19 adenocarcinomas and 22 squamous cell carcinomas).

RESULTS

Overexpression of the apoptosis inhibitors Bcl-2 and Bcl-X(L) was observed in 10 of 41 samples (24%) and in 11 of 41 samples (27%), respectively. Loss of expression of proapoptotic proteins was observed as follows: Bak, 24 of 41 samples (59%); Bad, 21 of 41 samples (51%); Bid, 20 of 41 samples (49%); Bax, 14 of 41 samples (34%); and Bim/Bod, 2 of 41 samples (5%). Statistically significant differences in expression between adenocarcinoma samples and squamous cell carcinoma samples were observed for Bcl-X(L) (overexpression in 11 of 19 adenocarcinomas [58%] vs. 0 of 22 squamous cell carcinomas [0%]; P < 0.001) and for Bad (loss of expression in 5 of 19 adenocarcinomas [26%] vs. 16 of 22 squamous cell carcinomas [73%]; P = 0.004).

CONCLUSIONS

Although this was only a pilot study, the results revealed significant differences in the expression of apoptosis-related proteins both between individual samples of nonsmall cell lung carcinoma and between the two main histologic subtypes. Such differences may play a role in the development of lung tumors; and, if it is found that these differences are of clinical importance, then it may be required to regard nonsmall cell lung carcinoma subtypes as separate entities rather than as one disease.

The role of bcl-2 family members in non-small cell lung cancer

The treatment of advanced nonsmall cell lung cancer (NSCLC) continues to pose great challenges for the thoracic surgeon. Current therapeutic strategies with chemotherapy and radiation are often ineffective adjuncts to surgery. Accordingly, preclinical research concentration has turned to molecular targets that may prove to be more effective. The Bcl-2 family consists of a homologous network of genes that regulate apoptosis or programmed cell death. Altered expression of members in this family leads to aberrant cell proliferation and malignant growth. This review will discuss the expression and significance of Bcl-2 family members in NSCLC and consider potential methods of intervention that are currently being tested and may have clinical applicability. In addition, the current experience with clinical trials involving Bcl-2 down-regulation in solid organ tumors will be summarized.