Apoptosome-dependent caspase activation proteins as prognostic markers in Stage II and III colorectal cancer

The power of mumps virus: Matrix protein activates apoptotic pathways in human colorectal cell lines

New therapeutic approaches can significantly impact the control of colorectal cancer (CRC), which is increasing worldwide. In this study, we investigated the potential of targeting viral proteins to combat cancer cells. Specifically, we examined the anticancer potential of the matrix (M) protein of the mumps virus Hoshino strain in SW480 CRC cell lines. To begin, we individually transfected SW480 cells with pcDNA3 plasmids containing the mumps virus M gene. We then investigated the percentage of cell death, caspase activity, and the expression levels of genes involved in apoptosis pathways. Following this, we performed bioinformatics analysis on the M protein to identify any similarities with Bcl-2 family members and their viral homologs. Our diagnostic methods showed that treatment with the mumps M protein induced apoptosis and upregulated the expression and activity of pro-apoptotic proteins in SW480 CRC cells compared to the control and vector groups. Based on our bioinformatics studies, we proposed that the BH3 motif in the M protein may trigger apoptosis in CRC cells by interacting with cellular Bax. Overall, our study showed for the first time that the mumps virus M protein could be considered as a targeted treatment for CRC by inducing apoptotic pathways.

Impairment of apoptosis pathway via Apaf1 downregulation during chlorpyrifos and/or cypermethrin induced lung damage

Chlorpyrifos is an organophosphate and the cypermethrin is type 2 pyrethroid insecticide that are used for indoor and outdoor pest control. The present study aimed to investigate differential transcriptional profiling to identify the candidate gene associated with lung injury following exposure to chlorpyrifos and/or cypermethrin in a mouse model system. Swiss male albino mice (n = 24) were divided into three treatment groups (n = 6 each) that were given chlorpyrifos (2.76 mg kg^-1 body weight), cypermethrin (2 mg kg^-1 body weight) and the combination of both pesticides orally dissolved in corn oil and one control group (n = 6) that received corn oil for 90 days. The pulmonary expression of the Apaf1 was observed using RT2 Profiler PCR Array. The results showed that chronic exposure to chlorpyrifos, cypermethrin and their combination downregulated (67, 63 and 66 genes) and upregulated (4, 2 and 2 genes), respectively. The pulmonary expression of Apaf1 that plays important role in apoptosis was found to be downregulated. The immunohistochemistry depicted reduced expression of Apaf1 in both airway epithelium and alveolar septa following exposure to chlorpyrifos and/or cypermethrin. In conclusion, results demonstrated that exposure to chlorpyrifos, cypermethrin and their combination cause lung damage by the dysregulation of Apaf1 gene expression.

Prognostic significance of X-linked inhibitor of apoptosis protein in patients with gastrointestinal tract cancers: A meta-analysis

BACKGROUND

The aim of this meta-analysis was to systematically evaluate the prognostic significance of X-linked inhibitor of apoptosis protein (XIAP) in patients with gastrointestinal tract (GIT) cancers.

METHODS

PubMed, Web of Science, EMBASE, Cochrane Library and China National Knowledge Infrastructure were searched for potentially eligible literature. The baseline characteristics and relevant data were extracted. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated to assess the prognostic role of XIAP in patients with GIT cancers.

RESULTS

Twelve studies with 2,477 patients were included. The pooled HRs of higher expression of XIAP for overall survival (OS) and recurrence free survival (RFS) in patients with GIT cancers were 1.64 (95% CI, 1.27-2.13) and 1.06 (95% CI, 0.96-1.16), respectively. Subgroup analysis and sensitivity analysis were also performed. No significant publication bias was found.

CONCLUSION

Our results suggested that XIAP could be a prognostic marker for OS but not RFS in patients with GIT cancers. Higher expression of XIAP was related to poorer OS. These findings may help evaluate the prognosis of patients and assist future research on novel therapeutic strategies of GIT cancers by targeting XIAP. However, more well-designed studies are warranted to verify the results.

Procaspase-3 Overexpression in Cancer: A Paradoxical Observation with Therapeutic Potential

Many anticancer strategies rely on the promotion of apoptosis in cancer cells as a means to shrink tumors. Crucial for apoptotic function are executioner caspases, most notably caspase-3, that proteolyze a variety of proteins, inducing cell death. Paradoxically, overexpression of procaspase-3 (PC-3), the low-activity zymogen precursor to caspase-3, has been reported in a variety of cancer types. Until recently, this counterintuitive overexpression of a pro-apoptotic protein in cancer has been puzzling. Recent studies suggest subapoptotic caspase-3 activity may promote oncogenic transformation, a possible explanation for the enigmatic overexpression of PC-3. Herein, the overexpression of PC-3 in cancer and its mechanistic basis is reviewed; collectively, the data suggest the potential for exploitation of PC-3 overexpression with PC-3 activators as a targeted anticancer strategy.

Prognostic Value of XIAP Level in Patients with Various Cancers: A Systematic Review and Meta-Analysis

Background: X-linked inhibitor of apoptosis protein (XIAP) plays an important role in cancer pathogenesis, which has been found to be overexpressed in multiple human cancers and associated with survival rates. Herein, we performed a meta-analysis to explore the predictive value of XIAP level in patients with various solid tumors. Methods: Relevant articles exploring the relationship between XIAP expression and survival of cancer patients were retrieved in PubMed, PMC, EMBASE and Web of Science published from 2001 to 2018. The combined hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to evaluate the significance. Results: A total of 6554 patients from 40 articles were included in this meta-analysis. It was shown in 37 studies with 4864 cases that the over-expression of XIAP was associated with poorer overall survival (OS) (combined HR=1.61, 95% CI: 1.33-1.96). Meanwhile, 8 studies with 1862 cases revealed that elevated XIAP level predicted shorter disease-free survival (DFS) (HR=2.17, 95% CI: 1.03-4.59). Subgroup analyses showed that higher XIAP detection was related to worse OS in gastric cancer (HR=1.42, 95% CI: 1.18-1.72) and head and neck cancer (HNC) (HR=2.97, 95% CI: 1.97-4.47). Conclusion: Our results suggested that elevated XIAP level seemed to represent an unfavorable prognostic factor for clinical outcomes in cancer patients. However, there were limited studies describing the association between XIAP expression and clinical prognosis in each different type of tumors. Therefore, concrete roles of XIAP in various cancers need to be further explored.

Expression Level of Caspase Genes in Colorectal Cancer

Background:

Caspases proteins are protease enzymes involved in the initiation and execution of apoptosis process. Regulation of apoptosis process plays an important role in the normal biological events and development. In addition to developmental abnormalities, dysregulated apoptosis system may lead to tumorigenesis, autoimmunity, and other serious health problems. Aberrant regulation of apoptosis may also be the paramount cause of chemoresistance during cancer therapy. It is aimed through this study to evaluate the transcript levels of Caspase 3, 8, and 9 in tumoral tissues from patients with colorectal cancer (CRC) and compare it with normal marginal tissues.

Methods:

Fifty tumor tissues and their matched marginal tissues, as control group, were obtained from CRC patients. Total mRNA of all tissue samples was extracted and cDNA was synthesized. Using SYBR Green PCR master mix and Real-time gene expression technique, the transcript level of target genes was quantified.

Results:

Experiments indicated that mRNA expressions of caspase 9 and 3 were downregulated in tumoral tissues from CRC patients in comparison to marginal tissues. In contrast, tumoral tissues expressed mRNA of caspase 8 higher than normal marginal tissues. Modified transcript levels of caspase 3, 8, and 9 were correlated with the clinical manifestations of the patients.

Conclusions:

Alteration in the mRNA level of caspase genes may be involved in the development of CRC.

Activated Caspase 3 Expression in Remnant Disease After Neoadjuvant Chemotherapy May Predict Outcomes of Breast Cancer Patients

BACKGROUND

A number of studies have indicated that patients obtaining a pathological complete response (pCR) from neoadjuvant chemotherapy (NAC) have a good prognosis; however, prognostic factors for non-pCR patients are not yet well-established. By examining remnant cancer in non-pCR patients, the expression of cleaved Caspase 3 (Casp3), an activated apoptotic marker, was immunohistochemically investigated to determine whether this protein has the potential to serve as a novel marker for predicting patient outcomes.

METHODS

We investigated 218 patients with invasive breast cancer who received NAC and underwent surgery during the 2006 through 2008 period at our institution. Following surgery, standard adjuvant endocrine therapy was administered if a tumor was hormone receptor-positive. Casp3 was evaluated in remnant cancer based on the number of positive cells in five high-power fields.

RESULTS

pCR was obtained in 49 patients, and 50 of the 169 non-pCR patients developed recurrences during the median 82-month observation period. We found large tumor size, lymph node involvement, lymph vessel invasion, estrogen receptor-negative, progesterone receptor-negative, high Ki67 and high Casp3 expression to be factors related to tumor recurrence. A logistic regression model revealed that lymph node involvement, as well as high Ki67 and Casp3, to be factors independently predicting recurrence, while lymph vessel invasion and high Ki67 expression were found to be related to breast cancer mortality.

CONCLUSIONS

Patients with remnant cancer showing high Casp3 expression had poor outcomes. Our results showed that Casp3 is a potential prognostic marker for non-pCR patients.

Derivatives of Procaspase-Activating Compound 1 (PAC-1) and their Anticancer Activities

PAC-1 induces the activation of procaspase-3 in vitro and in cell culture by chelation of inhibitory labile zinc ions via its ortho-hydroxy-N-acylhydrazone moiety. First reported in 2006, PAC-1 has shown promise in cell culture and animal models of cancer, and a Phase I clinical trial in cancer patients began in March 2015 (NCT02355535). Because of the considerable interest in this compound and a well-defined structure-activity relationship, over 1000 PAC-1 derivatives have been synthesized in an effort to vary pharmacological properties such as potency and pharmacokinetics. This article provides a comprehensive examination of all PAC-1 derivatives reported to date. A survey of PAC-1 derivative libraries is provided, with an indepth discussion of four derivatives on which extensive studies have been performed.

Chromatin status of apoptosis genes correlates with sensitivity to chemo-, immune- and radiation therapy in colorectal cancer cell lines

The apoptosis pathway of programmed cell death is frequently deregulated in cancer. An intact apoptosis pathway is required for proper response to anti-cancer treatment. We investigated the chromatin status of key apoptosis genes in the apoptosis pathway in colorectal cancer cell lines in relation to apoptosis induced by chemo-, immune- or radiation therapy. Using chromatin immunoprecipitation (ChIP), we measured the presence of transcription-activating histone modifications H3Ac and H3K4me3 and silencing modifications H3K9me3 and H3K27me3 at the gene promoter regions of key apoptosis genes Bax, Bcl2, Caspase-9, Fas (CD95) and p53. Cell lines DLD1, SW620, Colo320, Caco2, Lovo and HT29 were treated with cisplatin, anti-Fas or radiation. The apoptotic response was measured by flow cytometry using propidium iodide and annexin V-FITC. The chromatin status of the apoptosis genes reflected the activation status of the intrinsic (Bax, Bcl2, Caspase-9 and p53) and extrinsic (Fas) pathways. An active intrinsic apoptotic pathway corresponded to sensitivity to cisplatin and radiation treatment of cell lines DLD1, SW620 and Colo320. An active Fas promoter corresponded to an active extrinsic apoptotic pathway in cell line DLD1. mRNA expression data correlated with the chromatin status of the apoptosis genes as measured by ChIP. In conclusion, the results presented in this study indicate that the balance between activating and silencing histone modifications, reflecting the chromatin status of apoptosis genes, can be used to predict the response of tumor cells to different anti-cancer therapies and could provide a novel target to sensitize tumors to obtain adequate treatment responses.

DNA methylation of apoptosis genes in rectal cancer predicts patient survival and tumor recurrence

Deregulation of the apoptotic pathway, one of the hallmarks of tumor growth and -progression, has been shown to have prognostic value for tumor recurrence in rectal cancer. In order to develop clinically relevant biomarkers, we studied the methylation status of promoter regions of key apoptosis genes in rectal cancer patients, using methylation-sensitive restriction enzymes. DNA was extracted from fresh-frozen tumor tissues of 49 stage I-III rectal cancer patients and 10 normal rectal tissues. The results of this pilot study were validated in 88 stage III tumor tissues and 18 normal rectal tissues. We found that methylation of the intrinsic apoptotic pathway genes Apaf1, Bcl2 and p53 correlated with the apoptotic status (M30) of the tumor. Combined survival analyses of these three genes, based on the number of genes showing high methylation (all low, 1 high, 2 high or all high), showed shorter patient survival and recurrence-free periods with an increasing number of methylated markers. Multivariate analyses showed significant differences for overall survival (p = 0.01; HR = 0.28 (0.09-0.83)), cancer-specific survival (p = 0.004; HR = 0.13 (0.03-0.67)) and distant recurrence-free survival (p = 0.001; HR = 0.22(0.05-0.94)). The shortest survival was observed for patients showing low methylation of all markers, which-as was expected-correlated with high apoptosis (M30), but also with high proliferation (Ki-67). The study of epigenetic regulation of apoptosis genes provides more insight in the tumorigenic process in rectal cancer and might be helpful in further refining treatment regimens for individual patients.

Prognostic value of Caspase-3 expression in cancers of digestive tract: a meta-analysis and systematic review

Various studies have evaluated the relationship between Caspase-3 expression and cancers of digestive tract. However, the prognostic value of Caspase-3 expression remains unclear. Hence, a meta-analysis was conducted with eligible studies which quantitatively evaluated the relationship between Caspase-3 expression and survival of patients in gastrointestinal tract cancers. Electronic databases updated to April 12(th), 2015 were searched to obtain relevant primary articles. Twelve studies were finally included with 2402 patients of esophageal, gastric or colorectal cancers. The detection of Caspase-3 was performed by immunohistochemistry (IHC). Survival data were aggregated and quantitatively analyzed. Combined hazard ratios (HRs) suggested that Caspase-3 expression had no specific impact on the overall survival (OS) (HR=0.94, 95% CI (0.64-1.37), I(2)=79.6%, P<0.001) of cancers of digestive tract. When each subtype of gastrointestinal cancer was analyzed separately, the over-expression of Caspase-3 was associated with favorable prognosis of OS in esophageal cancer HR=0.31, 95% CI (0.09-1.09), I(2)=54.6%, P=0.138). On the contrary, high level of Caspase-3 was correlated with poor prognosis of OS in gastric cancer HR=1.53, 95% CI (0.93-2.50), I(2)=46.4%, P=0.172). However, the expression of Caspase-3 showed no relationship of OS for patients with colorectal cancer (HR=1.03, 95% CI (0.66-1.63), I(2)=0.0%, P=0.410). Furthermore, the Caspase-3 expression was an indicator of poor prognosis of recurrence-free survival (RFS) for digestive tract cancer (HR=1.65, 95% CI (1.12-2.41), I(2)=43.9%, P=0.148). More studies need to be carried out to certify the prognostic value of Caspase-3 expression for patients with digestive tract cancers.

Removal of Metabolic Liabilities Enables Development of Derivatives of Procaspase-Activating Compound 1 (PAC-1) with Improved Pharmacokinetics

Procaspase-activating compound 1 (PAC-1) is an o-hydroxy-N-acylhydrazone that induces apoptosis in cancer cells by chelation of labile inhibitory zinc from procaspase-3. PAC-1 has been assessed in a wide variety of cell culture experiments and in vivo models of cancer, with promising results, and a phase 1 clinical trial in cancer patients has been initiated (NCT02355535). For certain applications, however, the in vivo half-life of PAC-1 could be limiting. Thus, with the goal of developing a compound with enhanced metabolic stability, a series of PAC-1 analogues were designed containing modifications that systematically block sites of metabolic vulnerability. Evaluation of the library of compounds identified four potentially superior candidates with comparable anticancer activity in cell culture, enhanced metabolic stability in liver microsomes, and improved tolerability in mice. In head-to-head experiments with PAC-1, pharmacokinetic evaluation in mice demonstrated extended elimination half-lives and greater area under the curve values for each of the four compounds, suggesting them as promising candidates for further development.

Cell death controlling complexes and their potential therapeutic role

Programmed cell death plays a central role in the regulation of homeostasis and development of multicellular organisms. Deregulation of programmed cell death is connected to a number of disorders, including cancer and autoimmune diseases. Initiation of cell death occurs in the multiprotein complexes or high molecular weight platforms. Composition, structure, and molecular interactions within these platforms influence the cellular decision toward life or death and, therefore, define the induction of a particular cell death program. Here, we discuss in detail the key cell-death complexes-including DISC, complex II, and TNFRI complex I/II, and the necrosome, RIPoptosome, apoptosome, and PIDDosome-that control apoptosis or necroptosis pathways as well as their regulation. The possibility of their pharmacological targeting leading to the development of new strategies of interference with cell death programs via control of the high molecular weight platforms will be discussed.

Decreased expression of APAF-1 and increased expression of cathepsin B in invasive pituitary adenoma

PURPOSE

Apoptotic protease-activating factor-1 (APAF-1) and cathepsin B are important functional proteins in apoptosis; the former is involved in the intrinsic (mitochondrial) pathway, while the latter is associated with both intrinsic and extrinsic pathways. Changes in the expression of apoptosome-related proteins could be useful indicators of tumor development since a priori defects in the mitochondrial pathway might facilitate the inception and progression of human neoplasms. Our aim was to evaluate the profiles of APAF-1 and cathepsin B in relation with other molecules involved in apoptosis/proliferation and to correlate them with the aggressive behavior of invasive pituitary adenomas.

MATERIALS AND METHODS

APAF-1 and cathepsin B were assessed in tissue samples from 30 patients with pituitary adenomas, of which 16 were functional adenomas and 22 were invasive adenomas.

RESULTS

A positive relationship between high proliferation and invasiveness was observed in invasive pituitary adenomas when compared to their noninvasive counterparts (Ki-67 labeling index - 4.72% versus 1.75%). Decreased expression of APAF-1 was recorded in most of the invasive adenomas with a high proliferation index, while the cathepsin B level was elevated in this group. We have noticed a negative correlation between the low level of APAF-1 and invasiveness (63.63%; P<0.01); at the same time, a positive correlation between cathepsin B expression and invasiveness (59.09%; P<0.01) was found. In all, 81.25% out of the total APAF-1-positive samples were cathepsin B negative (P<0.01); 76.92% out of the total cathepsin B-positive samples were APAF-1-negative (P<0.01). These results were reinforced by an apoptosis protein array examination, which showed inhibition of the extrinsic apoptotic pathway in an invasive pituitary adenoma.

CONCLUSION

A bidirectional-inverted relationship between APAF-1 and cathepsin B expressions was noticed. One might hypothesize that shifting the balance between mediators of cell death could result in changes in tumor behavior.

Identification of clinically relevant molecular subtypes in colorectal cancer: the dawning of a new era

In recent years, a number of protein and genomic-based biomarkers have begun to refine the prognostic information available for colorectal cancer (CRC) and predict defined patient groups that are likely to benefit from systemic treatment or targeted therapies. Of these, KRAS represents the first biomarker integrated into clinical practice for CRC. Microarray-based gene expression profiling has been used to identify prognostic signatures and, to a lesser extent, predictive signatures in CRC. Despite these advances, a number of major challenges remain. This article, which is based on a lecture delivered as part of the 2013 Bob Pinedo Cancer Care Prize, reviews the impact of molecular biomarkers on the management of CRC, emphasizing changes that have occurred in recent years, and focuses on potential mechanisms of patient stratification and opportunities for novel therapeutic development based on enhanced biological understanding of colorectal cancer.

Harnessing system models of cell death signalling for cytotoxic chemotherapy: towards personalised medicine approaches?

Most cytotoxic chemotherapeutics are believed to kill cancer cells by inducing apoptosis. Understanding the factors that contribute to impairment of apoptosis in cancer cells is therefore critical for the development of novel therapies that circumvent the widespread chemoresistance. Apoptosis, however, is a complex and tightly controlled process that can be induced by different classes of chemotherapeutics targeting different signalling nodes and pathways. Moreover, apoptosis initiation and apoptosis execution strongly depend on patient-specific, genomic and proteomic signatures. Here, we will review recent translational studies that suggest a critical link between the sensitivity of cancer cells to initiate apoptosis and clinical outcome. Next we will discuss recent advances in the field of system modelling of apoptosis pathways for the prediction of treatment responses. We propose that initiation of mitochondrial apoptosis, defined as the process of mitochondrial outer membrane permeabilisation (MOMP), is a dose-dependent decision process that allows for a prediction of individual therapy responses and therapeutic windows. We provide evidence in contrast that apoptosis execution post-MOMP may be a binary decision that dictates whether apoptosis is executed or not. We will discuss the implications of this concept for the future use of novel adjuvant therapeutics that specifically target apoptosis signalling pathways or which may be used to reduce the impact of cell-to-cell heterogeneity on therapy responses. Finally, we will discuss the technical and regulatory requirements surrounding the use and implications of system-based patient stratification tools for the future of personalised oncology.

Systems analysis of cancer cell heterogeneity in caspase-dependent apoptosis subsequent to mitochondrial outer membrane permeabilization

Deregulation of apoptosis is a hallmark of carcinogenesis. We here combine live cell imaging and systems modeling to investigate caspase-dependent apoptosis execution subsequent to mitochondrial outer membrane permeabilization (MOMP) in several cancer cell lines. We demonstrate that, although most cell lines that underwent MOMP also showed robust and fast activation of executioner caspases and apoptosis, the colorectal cancer cell lines LoVo and HCT-116 Smac(-/-), similar to X-linked inhibitor of apoptosis protein (XIAP)-overexpressing HeLa (HeLa XIAP(Adv)) cells, only showed delayed and often no caspase activation, suggesting apoptosis impairment subsequent to MOMP. Employing APOPTO-CELL, a recently established model of apoptosis subsequent to MOMP, this impairment could be understood by studying the systemic interaction of five proteins that are present in the apoptosis pathway subsequent to MOMP. Using APOPTO-CELL as a tool to study detailed molecular mechanisms during apoptosis execution in individual cell lines, we demonstrate that caspase-9 was the most important regulator in DLD-1, HCT-116, and HeLa cells and identified additional cell line-specific co-regulators. Developing and applying a computational workflow for parameter screening, systems modeling identified that apoptosis execution kinetics are more robust against changes in reaction kinetics in HCT-116 and HeLa than in DLD-1 cells. Our systems modeling study is the first to draw attention to the variability in cell specific protein levels and reaction rates and to the emergent effects of such variability on the efficiency of apoptosis execution and on apoptosis impairment subsequent to MOMP.