Molecular analysis and prognostic impact of the novel apoptotic gene BCL2L12 in gastric cancer

NUDT1 Could Be a Prognostic Biomarker and Correlated with Immune Infiltration in Clear Cell Renal Cell Carcinoma

Background

Clear cell renal cell carcinoma (ccRCC) is a malignant tumor with high morbidity and mortality. As a member of the Nudix hydrolase superfamily, Nudix (nucleoside diphosphate-linked moiety X)-type motif 1 (NUDT1) is closely related to the occurrence and development of cancer. Our study aims to explore the role of NUDT1 in ccRCC and its relationship with immune infiltration.

Methods

The NUDT1 expression matrix and corresponding clinical information were obtained from The Cancer Genome Atlas (TCGA) database. The expression difference of NUDT1 in ccRCC and its relationship with the clinical characteristics were investigated using R software. Kaplan-Meier (K-M) analysis, univariate Cox regression, multivariate Cox regression, receiver operating characteristic (ROC) curve, and nomogram were utilized to evaluate the survival and prognosis of patients. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were utilized to explore the function of differential genes in low- or high-expression group of NUDT1. TCGA dataset and Tumor IMmune Estimation Resource (TIMER) database were utilized to explore the relationship between NUDT1 and immune infiltration. Finally, TCGA dataset was utilized for gene set enrichment analysis (GSEA).

Results

NUDT1 was not only overexpressed in ccRCC but also significantly correlated with clinicopathological features (P < 0.05). K-M survival analysis showed that upregulated NUDT1 was closely related to the decrease of overall survival (OS) and progression-free survival (PFS) in ccRCC patients. Multivariate Cox regression revealed that NUDT1 was a independent prognostic indicator (HR = 1.437, 95% CI: 1.065-1.939, P=0.018). The ROC curve showed that NUDT1 had a certain accuracy in predicting the outcome of ccRCC patiens. Furthermore, a total of 150 coexpressed genes and 1,886 differentially expressed genes (DEGs) were identified. GO/KEGG and GSEA results suggested that NUDT1 and its DEGs were involved in the immune-related pathways. NUDT1 expression was positively correlated with infiltrating levels of regulatory T cells (Tregs), CD8⁺ T cells, follicular helper T cells, and M0 macrophages. In addition, NUDT1 was positively related to immune checkpoints, such as PD-1, LAG3, CTLA4, and CD70, in ccRCC.

Conclusion

NUDT1 plays a key role in the prognosis and immune cell infiltration of ccRCC patients, indicating its potential use as a prognostic biomarker and therapeutic target.

Screening for Biomarkers for Progression from Oral Leukoplakia to Oral Squamous Cell Carcinoma and Evaluation of Diagnostic Efficacy by Multiple Machine Learning Algorithms

The aim of the study is to identify key genes during the progression from oral leukoplakia (OL) to oral squamous cell carcinoma (OSCC) and predict effective diagnoses. Weighted gene co-expression network analysis (WGCNA) and differential expression analysis were performed to identify seven genes associated with the progression from OL to OSCC. Twelve machine learning algorithms including k-nearest neighbor (KNN), neural network (NNet), and extreme gradient boosting (XGBoost) were used to construct multi-gene models, which revealed that each model had good diagnostic efficacy. The functional mechanism or the pathways associated with these genes were evaluated using enrichment analysis, subtype clustering, and immune infiltration analysis. The enrichment analysis revealed that the genes enriched were associated with the cell cycle, cell division, and intracellular energy metabolism. The immunoassay results revealed that the genes primarily affected the infiltration of proliferating T cells and macrophage polarization. Finally, a nomogram and Kaplan-Meier survival analysis were used to predict the prognostic efficacy of key genes in OSCC patients. The results showed that genes could predict the prognosis of the patients, and patients in the high-risk group had a poor prognosis. Our study identified that the seven key genes, including DHX9, BCL2L12, RAD51, MELK, CDC6, ANLN, and KIF4A, were associated with the progression from OL to OSCC. These genes had good diagnostic efficacy and could be used as potential biomarkers for the prognosis of OSCC patients.

Spherical Nucleic Acids as Precision Therapeutics for the Treatment of Cancer-From Bench to Bedside

Spherical Nucleic Acids (SNAs) emerged as a new class of nanotherapeutics consisting of a nanoparticle core densely functionalized with a shell of radially oriented synthetic oligonucleotides. The unique three-dimensional architecture of SNAs protects the oligonucleotides from nuclease-mediated degradation, increases oligonucleotide bioavailability, and in the absence of auxiliary transfection agents, enables robust uptake into tumor and immune cells through polyvalent association with cell surface pattern recognition receptors. When composed of gene-regulatory small interfering (si)RNA or immunostimulatory DNA or RNA oligonucleotides, SNAs silence gene expression and induce immune responses superior to those raised by the oligonucleotides in their "free" form. Early phase clinical trials of gene-regulatory siRNA-based SNAs in glioblastoma (NCT03020017) and immunostimulatory Toll-like receptor 9 (TLR9)-agonistic SNAs carrying unmethylated CpG-rich oligonucleotides in solid tumors (NCT03086278) have shown that SNAs represent a safe, brain-penetrant therapy for inhibiting oncogene expression and stimulating immune responses against tumors. This review focuses on the application of SNAs as precision cancer therapeutics, summarizes the findings from first-in-human clinical trials of SNAs in solid tumors, describes the most recent preclinical efforts to rationally design next-generation multimodal SNA architectures, and provides an outlook on future efforts to maximize the anti-neoplastic activity of the SNA platform.

Identification of microRNA Signature and Key Genes Between Adenoma and Adenocarcinomas Using Bioinformatics Analysis

Background

In worldwide, colorectal cancer (CRC) is very common and the mechanisms remain unclear. This study aims to identify between adenomas with epithelial dislocation (false invasion) and adenomas with early adenocarcinoma (true invasion).

Methods

GSE41655 and GSE57965 datasets were obtained in the Gene Expression Omnibus (GEO) database. microRNA expression profiles and clinicopathological data from the TCGA (The Cancer Genome Atlas) database were downloaded to further validate the results in GEO. GEO software and the GEO2R calculation method were used to analyze two gene profiles. The co-expression of differentially expressed microRNAs (DEMs) and genes (DEGs) were identified and searched in the FunRich databases for pathway and ontology analysis. Cytoscape was utilized to construct the mRNA-microRNA network. Validation of gene expression levels was conducted by online databases and qRT-PCR and IHC experiments.

Results

In total, 6 DEMs and 34 DEGs are selected after calculating. KEGG results indicated that genes are enriched in certain tumor associated pathways. Four out of 6 microRNAs had a significant relationship with the overall survival (P < 0.05) and showed a good performance in predicting the survival risk of patients with colorectal carcinoma. Furthermore, expression levels of hsa-miR-455 and hsa-miR-125a were then verified by qRT-PCR which all target BCL2L12. IHC results showed that the expression level of BCL2L12 was higher in adenocarcinoma than in adenoma. Based on the selected gene, the top 10 small molecules were screened out as potential drugs.

Conclusion

By using microarray and bioinformatics analyses, DEMs and DEGs were selected and a complete gene network was constructed. To our knowledge, BCL2L12 and related molecules including hsa-miR-455 and hsa-miR-125a were firstly identified as potential biomarkers in the progression from adenoma to adenocarcinoma.

Positive BCL2L12 expression predicts favorable prognosis in patients with laryngeal squamous cell carcinoma

BACKGROUND

Laryngeal squamous cell carcinoma (LSCC) constitutes the third most frequent head and neck cancer. Several tissue biomarkers have been studied for their prognostic significance in LSCC.

OBJECTIVE

To investigate the prognostic significance of BCL2L12, a new member of the BCL2 family, in primary LSCC along with well-examined biomarkers such as BCL2 and BAX.

METHODS

Cancerous tissue specimens of patients with primary LSCC were collected during 2005 and 2012 as pretreatment tissue biopsy. The specimens were immunohistochemically evaluated for the protein expression of BCL2L12, BCL2 and BAX. Kaplan-Meier survival curves and Cox proportional hazard regression models were performed to evaluate prognosis.

RESULTS

In the study cohort of 78 patients with primary LSCC, Kaplan-Meier survival curves demonstrated that advanced-stage LSCC patients with BCL2L12-positive tumors had significantly higher OS time in comparison with advanced-stage LSCC patients with BCL2L12-negative tumors (p= 0.014). Also, advanced-stage LSCC patients with BCL2L12-positive tumors had significantly lower risk of death from LSCC compared to advanced-stage LSCC patients with BCL2L12-negative tumors (HR = 0.228, 95%CI = 0.063-0.833, p= 0.025).

CONCLUSIONS

BCL2L12 protein expression could be used as a favorable prognostic tissue biomarker in patients with primary advanced-stage LSCC. On the contrary, BCL2 and BAX did not correlate with prognosis in patients with primary LSCC.

BCL2L12 improves risk stratification and prediction of BFM-chemotherapy response in childhood acute lymphoblastic leukemia

Background Risk-adjusted treatment has led to outstanding improvements of the remission and survival rates of childhood acute lymphoblastic leukemia (ALL). Nevertheless, overtreatment-related toxicity and resistance to therapy have not been fully prevented. In the present study, we evaluated for the first time the clinical impact of the apoptosis-related BCL2L12 gene in prognosis and risk stratification of BFM-treated childhood ALL. Methods Bone marrow specimens were obtained from childhood ALL patients upon disease diagnosis and the end-of-induction (EoI; day 33) of the BFM protocol, as well as from control children. Following total RNA extraction and reverse transcription, BCL2L12 expression levels were determined by qPCR. Patients' cytogenetics, immunophenotyping and minimal residual disease (MRD) evaluation were performed according to the international guidelines. Results BCL2L12 expression was significantly increased in childhood ALL and correlated with higher BCL2/BAX expression ratio and favorable disease markers. More importantly, BCL2L12 expression was associated with disease remission, while the reduced BCL2L12 expression was able to predict patients' poor response to BFM therapy, in terms of M2-M3 response and MRD≥0.1% on day 15. The survival analysis confirmed the significantly higher risk of the BFM-treated patients underexpressing BCL2L12 at disease diagnosis for early relapse and worse survival. Lastly, evaluation of BCL2L12 expression clearly strengthened the prognostic value of the established disease prognostic markers, leading to superior prediction of patients' outcome and improved specificity of BFM risk stratification. Conclusions The expression levels of the apoptosis-related BCL2L12 predict response to treatment and survival outcome of childhood ALL patients receiving BFM chemotherapy.

BCL2L12: a multiply spliced gene with independent prognostic significance in breast cancer

Background

Alternative splicing is a key process in carcinogenesis and, from a clinical aspect, holds great promises, as alternatively spliced variants have emerged as an untapped source of diagnostic and prognostic markers. Our aim was to assess the prognostic value of three recently recognized splice variants of the apoptosis-related gene, BCL2L12, in breast cancer (BC).

Methods

Total RNA was extracted from breast samples (150 BC and 80 tumor-adjacent normal tissues) and, following cDNA synthesis, a variant-specific qPCR was performed for the expressional quantification of BCL2L12 v.1, v.2 and v.4 transcript variants. Extensive statistical analysis, including bootstrap resampling and internal validation, was conducted in order to evaluate the associations of v.1, v.2 and v.4 expression with patients’ clinopathological and survival data.

Results

All examined BCL2L12 variants were significantly upregulated in BC specimens compared to their non-cancerous counterpart (v.1, p<0.001; v.2, p=0.009; v.4, p=0.004). Increased BCL2L12 v.4 mRNA expression was associated with markers of unfavorable prognosis namely, advanced tumor grade (p=0.002), ER- (p=0.015)/PR- (p<0.001) negativity, Ki-67-positivity (p=0.007) and high NPI (Nottingham prognostic index) score (p=0.033). Moreover, v.4 was significantly overexpressed in women with triple negative BC (TNBC) and HER2-positive tumors compared to those harboring luminal tumors (p<0.001). Survival analysis disclosed that BCL2L12 v.2 overexpression, as a continuous variable ([HR]=0.45, 95% CI=0.17–0.82, p=0.010), is a strong and independent marker of favorable prognosis for BC patients. Interestingly, v.2 retains its prognostic value in patients with Grade II/III ([HR]=0.21, 95% CI=0.05–0.57, p=0.006) or HER2-positive/TNBC tumors ([HR]=0.25, 95% CI=0.05–0.74, p=0.042).

Conclusions

BCL2L12 v.1, v.2, v.4 are aberrantly expressed in BC. Their expressional analysis by cost-effective molecular methods could provide a novel molecular tool for BC management.

Identification of novel alternative splice variants of the BCL2L12 gene in human cancer cells using next-generation sequencing methodology

The next-generation sequencing (NGS) technology has enabled genome-wide studies, providing massively parallel DNA sequencing. NGS applications constitute a revolution in molecular biology and genetics and have already paved new ways in cancer research. BCL2L12 is an apoptosis-related gene, previously cloned from members of our research group. Like most members of the BCL2 gene family, it is highly implicated in various types of cancer and hematological malignancies. In the present study, we used NGS to discover novel alternatively spliced variants of the apoptosis-related BCL2L12 gene in many human cancer cell lines, after 3'-RACE nested PCR. Extensive computational analysis uncovered new alternative splicing events and patterns, resulting in novel alternative transcripts of the BCL2L12 gene. PCR was then performed to validate NGS data and identify the derived novel transcripts of the BCL2L12 gene. Therefore, 50 novel BCL2L12 splice variants were discovered. Since BCL2L12 is involved in the apoptotic machinery, the quantification of distinct BCL2L12 transcripts in human samples may have clinical applications in different types of cancer.

The novel function of CD82 and its impact on BCL2L12 via AKT/STAT5 signal pathway in acute myelogenous leukemia cells

The aim of this study was to explore the biological functions of a tetraspanin family protein CD82 expressed aberrantly in chemotherapy-resistant CD34(+)/CD38(-) acute myelogenous leukemia (AML) cells. Microarray analysis of patient-isolated CD34(+)/CD38(-) AML cells revealed that the levels of anti-apoptotic protein BCL2L12 were downregulated after CD82 depletion by specific short hairpin RNA (shRNA). Western blot analysis indicated that BCL2L12 was aberrantly expressed in patient-isolated AML cells and AML cell lines. Furthermore, CD82 blockade by a specific antibody downregulated BCL2L12 in parallel with dephosphorylation of signal transducer and activator of transcription 5 (STAT5) and AKT, whereas pharmacological inhibition of STAT5 and AKT activation decreased BCL2L12 expression in leukemia cells. In addition, shRNA-mediated downregulation of BCL2L12 increased the levels of cleaved caspase-3 and suppressed proliferation of leukemia cells, impairing their engraftment in immunodeficient mice. Taken together, our results indicate that CD82 regulated BCL2L12 expression via STAT5A and AKT signaling and stimulated proliferation and engrafting of leukemia cells, suggesting that CD82 and BCL2L12 may be promising therapeutic targets in AML.

Differential roles of Bcl2L12 and its short variant in breast cancer lymph node metastasis

Bcl2L12 plays a role in post-mitochondrial apoptosis through multiple mechanisms involving p53, αB-crystallin, caspase-3 and -7 in glioblastoma. Bcl2L12 is reported to be a good prognostic marker in breast cancer and correlated with ER and Bcl2 expression status. However, the mechanisms by which Bcl2L12 regulates apoptosis in breast cancer (BCa) remain unknown. Recent studies have shown that Bcl2L12 expression is a useful biomarker in other types of cancer. Thus, we examined whether Bcl2L12 and Bcl2L12A mRNA were associated with breast cancer progression or a specific subtype. In total, 106 paraffin-embedded, different stage breast cancer specimens were prepared and quantified for Bcl2L12 and Bcl2L12A expression by PCR. The correlation between Bcl2L12 and Bcl2L12A mRNA levels and clinicopathological characteristics was statistically analyzed. The results showed that Bcl2L12 and Bcl2L12A mRNA expression was not significantly different across the different stage, grade and TNM classification groups (P>0.005). Using linear regression, Bcl2L12 mRNA was associated with Bcl2L12A mRNA, grade 3 tumor and the triple-negative breast cancer (TNBC) subtype. In non-TNBC specimens, Bcl2L12 mRNA was only correlated with Bcl2L12A mRNA. Bcl2L12A mRNA was positively associated with Bcl2L12 mRNA and the number of lymph node metastases, but negatively correlated with staging in the non-TNBC group. Specifically, Bcl2L12, but not Bcl2L12A, mRNA was significantly higher in TNBC and grade 3 tumors, respectively. In non-TNBC, Bcl2L12A mRNA was significantly highly expressed in tumors with ≥ 12 metastatic lymph nodes. Bcl2L12 and its variant mRNA were highly expressed in carcinoma in situ (CIS) samples. In addition, they were estimated to be correlated with the total sample and non-TNBC, but not the TNBC group. In summary, a high Bcl2L12 mRNA expression was associated with the high-grade BCa and TNBC subtype. In addition, the interplay between Bcl2L12 and its variant may be associated with high lymph node metastasis in non-TNBC tumors.

Clinicopathological and prognostic significance of p53, Ki-67, and Bcl-2 expression in Tunisian gastric adenocarcinomas

Gastric carcinoma (GC) is a highly aggressive malignancy with poor prognosis. It is widely accepted that malignancy results from abnormal cell growth due to dysregulation of the balance between cell proliferation and apoptosis. Our study aimed to investigate the clinicopathological and prognostic significance of p53, Ki-67, and Bcl-2 in Tunisian GC patients by immunohistochemistry. It was observed that the older patients showed p53 overexpression compared with the younger patients (p<0.05). There was higher p53 expression in the intestinal-type compared with the diffuse-type (p<0.05), and in well/moderate differentiated than in poor differentiated tumors. The expression of Ki-67 was positively associated with tumor size and venous invasion (p<0.05). Bcl2 expression occurred in male patients and correlated with depth of invasion (p=0.02). A Kaplan-Meier analysis indicated an inverse correlation between p53 and Ki-67 expression and the overall survival. Multivariate analysis revealed that the tumor site, Ki-67 and p53 expression were independent prognostic factors for gastric carcinomas (p<0.05). Finally, combined expression of p53, Ki-67 and Bcl-2 showed that the group of patients with tumors p53+/Ki-67+/Bcl2- had aggressive behavior and poor prognosis (p log rank=0.000). In summary, our data indicated that the expression of p53, Ki-67, and Bcl-2 may provide useful information for identifying patients with aggressive behavior and poor prognosis of GC.

Spherical nucleic acid nanoparticle conjugates as an RNAi-based therapy for glioblastoma

Glioblastoma multiforme (GBM) is a neurologically debilitating disease that culminates in death 14 to 16 months after diagnosis. An incomplete understanding of how cataloged genetic aberrations promote therapy resistance, combined with ineffective drug delivery to the central nervous system, has rendered GBM incurable. Functional genomics efforts have implicated several oncogenes in GBM pathogenesis but have rarely led to the implementation of targeted therapies. This is partly because many "undruggable" oncogenes cannot be targeted by small molecules or antibodies. We preclinically evaluate an RNA interference (RNAi)-based nanomedicine platform, based on spherical nucleic acid (SNA) nanoparticle conjugates, to neutralize oncogene expression in GBM. SNAs consist of gold nanoparticles covalently functionalized with densely packed, highly oriented small interfering RNA duplexes. In the absence of auxiliary transfection strategies or chemical modifications, SNAs efficiently entered primary and transformed glial cells in vitro. In vivo, the SNAs penetrated the blood-brain barrier and blood-tumor barrier to disseminate throughout xenogeneic glioma explants. SNAs targeting the oncoprotein Bcl2Like12 (Bcl2L12)--an effector caspase and p53 inhibitor overexpressed in GBM relative to normal brain and low-grade astrocytomas--were effective in knocking down endogenous Bcl2L12 mRNA and protein levels, and sensitized glioma cells toward therapy-induced apoptosis by enhancing effector caspase and p53 activity. Further, systemically delivered SNAs reduced Bcl2L12 expression in intracerebral GBM, increased intratumoral apoptosis, and reduced tumor burden and progression in xenografted mice, without adverse side effects. Thus, silencing antiapoptotic signaling using SNAs represents a new approach for systemic RNAi therapy for GBM and possibly other lethal malignancies.

CXC chemokines and chemokine receptors in gastric cancer: From basic findings towards therapeutic targeting

Gastric cancer is the fourth most common cancer, and the second-highest cause of cancer-related deaths worldwide. Despite extensive research to identify novel diagnostic and therapeutic agents, patients with advanced gastric cancer suffer from a poor quality of life and poor prognosis, and treatment is dependent mainly on conventional cytotoxic chemotherapy. To improve the quality of life and survival of gastric cancer patients, a better understanding of the underlying molecular pathologies, and their application towards the development of novel targeted therapies, is urgently needed. Chemokines are a group of small proteins associated with cytoskeletal rearrangements, the directional migration of several cell types during development and physiology, and the host immune response via interactions with G-protein coupled receptors. There is also growing evidence to suggest that chemokines not only play a role in the immune system, but are also involved in the development and progression of tumors. In gastric cancer, CXC chemokines and chemokine receptors regulate the trafficking of cells in and out of the tumor microenvironment. CXC chemokines and their receptors can also directly influence tumorigenesis by modulating tumor transformation, survival, growth, invasion and metastasis, as well as indirectly by regulating angiogenesis, and tumor-leukocyte interactions. In this review, we will focus on the roles of CXC chemokines and their receptors in the development, progression, and metastasis of gastric tumors, and discuss their therapeutic potential for gastric cancer.

Increased BCL2L12 expression predicts the short-term relapse of patients with TaT1 bladder cancer following transurethral resection of bladder tumors

OBJECTIVES

More than half of the diagnosed patients with bladder cancer (BCa) recur at least once following their initial treatment. Thus, patients' monitoring and prognosis is of utmost importance. However, the need for intensive surveillance of BCa significantly burdens patients' health-related quality of life. The aim of the present study is the expression analysis of BCL2L12, a recently identified member of the BCL2 apoptosis-related gene family, in BCa and the evaluation of BCL2L12 prognostic significance for the survival outcome of the patients.

METHODS AND MATERIALS

Our study included 115 patients with BCa, and tissue specimens were obtained from the tumor area as well as from adjacent normal bladder wall. BCL2L12 expression was determined using quantitative real-time polymerase chain reaction assay, and was further correlated with patients' clinicopathological features and follow-up survival data.

RESULTS

Up-regulated BCL2L12 expression levels were detected in malignant bladder specimens compared with normal ones. The higher BCL2L12 expression was further associated with shorter disease-free survival of the patients with BCa. Focusing on patients with TaT1 non-muscle invasive BCa, BCL2L12 expression levels were correlated with higher recurrence rate at the first follow-up cystoscopy and were unveiled to be an independent unfavorable predictor of patients' short-term recurrence following transurethral resection. Finally, BCL2L12 expression levels were also associated with poor disease-free survival of the high-grade TaT1 patients.

CONCLUSIONS

Our data highlight the unfavorable prognostic value of BCL2L12 for patients with BCa and support its potential clinical use for the assessment of TaT1 patients' recurrence risk.

Effect of doxorubicin, oxaliplatin, and methotrexate administration on the transcriptional activity of BCL-2 family gene members in stomach cancer cells

Defective apoptosis comprises the main reason for tumor aggressiveness and chemotherapy tolerance in solid neoplasias. Among the BCL-2 family members, whose mRNA or protein expression varies considerably in different human malignancies, BCL2L12 is the one for which we have recently shown its propitious prognostic value in gastric cancer. The purpose of the current work was to investigate the expression behavior of BCL2L12, BAX, and BCL-2 in human stomach adenocarcinoma cells following their exposure to anti-tumor substances. The 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide and trypan blue methods assessed the impact of doxorubicin, oxaliplatin and methotrexate on AGS cells' viability and growth. Following isolation from cells, total RNA was reverse-transcribed to cDNA. Quantification of target genes' expression was performed with real-time PCR using SYBR Green detection system. The relative changes in their mRNA levels between drug-exposed and untreated cells were calculated with the comparative Ct method (2(-ddCt)). All three drugs, as a result of their administration to AGS cancer cells for particular time intervals, provoked substantial fluctuations in the transcriptional levels of the apoptosis-related genes studied. While BAX was principally upregulated, striking similar were the notable changes regarding BCL-2 and BCL2L12 expression in our cellular system. Our findings indicate the growth suppressive effects of doxorubicin, oxaliplatin and methotrexate treatment on stomach carcinoma cells and the implication of BCL2L12, BAX, and BCL-2 expression profiles in the molecular signaling pathways triggered by chemotherapy.

Quantitative expression analysis of the apoptosis-related gene, BCL2L12, in head and neck squamous cell carcinoma

BACKGROUND

BCL2L12 is a recently identified gene belonging to the BCL2 family, members of which are implicated in head and neck squamous cell carcinoma (HNSCC). We have recently shown that BCL2L12 mRNA expression is an unfavorable prognostic indicator in nasopharyngeal carcinoma (NPC) and that BCL2L12 can be regarded as a novel, useful tissue biomarker for the prediction of NPC patients' short-term relapse. The aim of this study was to analyze the mRNA expression of the novel apoptosis-related gene BCL2L12 in patients with HNSCC.

METHODS

Total RNA was isolated from 53 malignant tumors originating in larynx, pharynx, tongue, buccal mucosa, parotid glands, and nasal cavity, as well as from 34 adjacent non-cancerous tissue specimens, resected from patients with HNSCC. A highly sensitive real-time PCR method for BCL2L12 mRNA quantification in head and neck tissues was developed using the SYBR(®) Green chemistry. After preparing cDNA by reverse transcription, relative quantification was performed using the comparative C(T) () method.

RESULTS

BCL2L12 mRNA levels were lower in laryngeal tumors of advanced tumor, node, metastasis (TNM) stage or bigger size and in well-differentiated malignant tongue neoplasms, compared with early-stage laryngeal tumors or poorly differentiated tongue tumors. Interestingly, the BCL2L12 expression showed significant discriminatory value, distinguishing efficiently patients with tongue squamous cell carcinoma (SCC) from non-cancerous population.

CONCLUSIONS

This is the first study examining the BCL2L12 mRNA expression in HNSCC. Our results suggest that BCL2L12 mRNA expression may serve as a potential prognostic biomarker in tongue and/or larynx SCC, which principally constitute the great majority of HNSCC cases worldwide.

Meta-analysis of the association of CYP1A1 polymorphisms with gastric cancer susceptibility and interaction with tobacco smoking

The association of two cytochrome P4501A1 (CYP1A1) polymorphisms, m1 (T6235C transition) and m2 (A4889G transition), with gastric cancer risk is inconclusive. We conducted a meta-analysis of all available studies to evaluate the potential role of the polymorphisms and their interactions with tobacco smoking in gastric cancer susceptibility. Published literature from PubMed was retrieved by two investigators independently. Fourteen case-control studies with 2,032 gastric cancer cases and 5,099 controls were selected. A fixed effects model or a random-effects model was used to estimate the odds ratio (OR) for the CYP1A1 polymorphisms and the occurrence of gastric cancer. Significant associations between CYP1A1 m1 and m2 polymorphisms and gastric cancer susceptibility were not observed in all genetic models in the overall analyses. Subgroup analyses by ethnicity and source of controls did not reveal significant associations with gastric cancer risk. Stratification analysis by smoking status found that carriers of the heterozygous and homozygous m1 genotypes decreased the susceptibility of gastric cancer among ever-smokers (pooled OR = 0.56, 95 % CI 0.36-0.89, fixed effects). In contrast, the m2 genotypes (G/G and A/G) did not show any relevance to gastric cancer risk among the smoking population (pooled OR = 1.30, 95 % CI 0.84-2.00, fixed effects). Overall, we found that the CYP1A1 polymorphism itself, either m1 or m2, did not represent an independent genetic risk factor influencing gastric cancer. However, subgroup analyses suggest that carriers of the heterozygous and homozygous m1 genotype who are exposed to tobacco smoke have a significantly lower risk of developing gastric cancer. To explain the observed reduction of gastric cancer risk, we proposed a novel hypothesis of "observation bias". This hypothesis is also applicable to explain the combined effects of other genetic polymorphisms and environmental factors on the risk of developing cancers, and the rationality of the hypothesis needs to be further investigated.

Molecular cloning of novel alternatively spliced variants of BCL2L12, a new member of the BCL2 gene family, and their expression analysis in cancer cells

In the past, we identified and cloned the BCL2-like 12 (BCL2L12) gene, a novel member of the BCL2 family, which is implicated in various malignancies. The classical BCL2L12 protein isoform contains a highly conserved BH2 domain, a BH3-like motif, and a proline-rich region, and is involved in apoptosis. Most members of this apoptosis-related family are subjected to alternative splicing, thus generating multiple protein isoforms with distinct properties, and sometimes even with opposite function (pro- vs. anti-apoptotic). In the current study, we report the identification, molecular cloning, and expression pattern of novel splice variants of the human BCL2L12 gene in cancer cell lines. EST clones displaying high sequence identity (≥90%) with the classical BCL2L12 transcript were aligned, in order to identify those containing at least one novel splice junction. EST database mining led to the identification of three previously unknown splice variants of this apoptotic gene. In our effort to experimentally validate these novel transcripts, we also cloned seven more, previously unidentified, BCL2L12 alternatively spliced variants. Expression analysis of all BCL2L12 splice variants in human cancer cell lines and embryonic kidney cells revealed remarkable differences between their BCL2L12 expression profiles. Interestingly, 7 out of 10 novel splice variants of BCL2L12 are predicted to encode new protein isoforms, some of which are BH3-only proteins, in contrast to the classical BCL2L12 isoform, which also contains a functional BH2 domain. The remaining three novel splice variants of BCL2L12 are nonsense-mediated mRNA decay (NMD) candidates.

The novel member of the BCL2 gene family, BCL2L12, is substantially elevated in chronic lymphocytic leukemia patients, supporting its value as a significant biomarker

BCL2L12 is a recently identified gene belonging to the BCL2 family, members of which are implicated in hematologic malignancies, including chronic lymphocytic leukemia (CLL). The aim of this study was to analyze the mRNA expression of the novel apoptosis-related gene BCL2L12 in patients with CLL and to examine its prognostic and predictive value and potential clinical application as a novel molecular biomarker for CLL. For this purpose, total RNA was isolated from peripheral blood of 65 CLL patients and 23 healthy donors. An ultrasensitive quantitative real-time polymerase chain reaction methodology for BCL2L12 and BCL2 mRNA quantification was developed using SYBR Green chemistry. After preparing cDNA by reverse transcription, relative quantification analysis was performed using the comparative C(T) (2(-ΔΔCT)) method. Furthermore, analysis of IGHV mutational status, CD38 expression, and detection of early apoptosis by double staining with Annexin V-FITC and propidium iodide were performed. According to our findings, BCL2L12 mRNA expression is significantly higher in CLL patients than in healthy donors. Receiver operating characteristic analysis demonstrated that BCL2L12 expression had significant discriminatory value, distinguishing very efficiently CLL patients from the non-leukemic population. Moreover, BCL2L12 expression predicts the presence of CLL, as demonstrated by both univariate and multivariate logistic regression analyses. Finally, high BCL2L12 mRNA levels are associated with advanced clinical stage and predict shorter overall survival in CLL patients.

Glycomic and glycoproteomic analysis of serum from patients with stomach cancer reveals potential markers arising from host defense response mechanisms

Despite the reduced incidence of gastric cancer in the developed world, a diagnosis of stomach carcinoma still carries a poor prognosis due to the asymptomatic nature of the disease in the early stages, subsequent advanced stage diagnosis, and a low 5 year survival rate. Endoscopy remains the primary standard for diagnosis of stomach carcinoma and the current marker, carbohydrate antigen 19-9 (CA19-9) lacks the levels of sensitivity and specificity required in order to make it clinically useful for diagnostic monitoring. Therefore, there is a current need for additional markers to improve the diagnostic accuracy for the early stages of stomach cancer. Together, glycomic, proteomic, and glycoproteomic analyses of serum have the potential to identify such probable markers. A discovery study is reported here using preoperative serum from 80 stomach cancer patients, 10 patients bearing benign stomach disease, and 20 matched controls. Glycomic analysis of the total and immunoaffinity depleted serum revealed statistically significant increases in the levels of sialyl Lewis X epitopes (SLe(X)) present on triantennary glycans accompanied by increased levels of core fucosylated agalactosyl biantennary glycans present on IgG (referred to as the IgG G0 glycoform) which are associated with increasing disease pathogenesis. Protein expression analysis using 2D-DiGE returned a number of differentially expressed protein candidates in the depleted serum, many of which were shown to carry triantennary SLe(X) during subsequent glycomic investigations. Biological pathway analysis of the experimental data returned complement activation and acute phase response signaling as the most significantly altered pathways in the stomach cancer patient serum. Upon the basis of these findings, it is suggested that increased expression of IgG G0 and complement activation are a host response to the presence of the stomach tumor while the increased expression of SLe(X) and acute phase response proteins is a result of pro-inflammatory cytokine signaling, including IL-6, during carcinogenesis. The approach presented herein provides an insight into the underlying mechanisms of disease and the resulting changes in the glycome and glycoproteome offer promise as potential markers for diagnosis and prognostic monitoring in stomach cancer.

Immune clearance gastric carcinoma cells in ascites by activating caspase-9-induced apoptosis

Floating gastric adenocarcinoma cells in ascitic fluid are the main cause of peritoneal dissemination. Activation of apoptosis is an important mechanism by which tumor cells are eliminated by the immune surveillance system. Hence, we examined caspase-9 expression and the apoptosis in gastric adenocarcinoma cells in ascitic fluid using immunohistochemistry, real-time polymerase chain reaction and in situ cell death detection kits, flow cytometry. The results revealed strong expression of caspase-9 in 58.49% (31/53) malignant cells and a relatively weak expression of caspase-9 in 41.51% (22/53) malignant cells. The proportion of apoptotic cells in 31 malignant cases with strong caspase-9 expression (35.14 ± 3.42)% was significantly higher than that in 22 malignant cases with relatively weak caspase-9 expression (17.29 ± 7.62)% or in mesothelial cells (10.76 ± 4.21%; p < 0.05). Kaplan-Meier survival curves demonstrated that the patients with low caspase-9 expression showed significantly shorter survival (p < 0.05) than those with high caspase-9 expression. These findings suggest that immune clearance gastric carcinoma cells in ascites activated by caspase-9 helped to improve the prognosis of patients with gastric cancer.

BCL2L12 is a novel biomarker for the prediction of short-term relapse in nasopharyngeal carcinoma

BCL2-like 12 (BCL2L12 ) is a new member of the apoptosis-related BCL2 gene family, members of which are implicated in various malignancies. Nasopharyngeal carcinoma is a highly metastatic, malignant epithelial tumor, with a high prevalence in Southeast Asia and North Africa. The purpose of the current study was to quantify and investigate the expression levels of the BCL2L12 gene in nasopharyngeal carcinoma biopsies and to assess its prognostic value. Total RNA was isolated from 89 malignant and hyperplastic nasopharyngeal biopsies from Tunisian patients. After testing the quality of the extracted RNA, cDNA was prepared by reverse transcription. A highly sensitive real-time polymerase chain reaction (PCR) method for BCL2L12 mRNA quantification was developed using SYBR Green chemistry. GAPDH served as a reference gene. Relative quantification analysis was performed using the comparative C(T) (2(-ΔΔCT)) method. Higher BCL2L12 mRNA levels were detected in undifferentiated carcinomas of the nasopharynx, rather than in nonkeratinizing nasopharyngeal tumors (P = 0.045). BCL2L12 expression status was also found to be positively associated with the presence of distant metastases (P = 0.014). Kaplan-Meier survival analysis demonstrated that patients with BCL2L12-positive nasopharyngeal tumors have significantly shorter disease-free survival (P = 0.020). Cox regression analysis showed BCL2L12 expression to be an unfavorable and independent prognostic indicator of short-term relapse in nasopharyngeal carcinoma (P = 0.042). Our results suggest that mRNA expression of BCL2L12 may constitute a novel biomarker for the prediction of short-term relapse in nasopharyngeal carcinoma.

Genetic and epigenetic alteration in gastric carcinogenesis

Gastric cancer (GC) is an important cause of morbidity and mortality worldwide. In addition to environmental factors, genetic factors also play an important role in GC etiology, as demonstrated by the fact that only a small proportion of individuals exposed to the known environmental risk factors develop GC. Molecular studies have provided evidence that GC arises not only from the combined effects of environmental factors and susceptible genetic variants but also from the accumulation of genetic and epigenetic alterations that play crucial roles in the process of cellular immortalization and tumorigenesis. This review is intended to focus on the recently described basic aspects that play key roles in the process of gastric carcinogenesis. Genetic variation in the genes DNMT3A, PSCA, VEGF, and XRCC1 has been reported to modify the risk of developing gastric carcinoma. Several genes have been newly associated with gastric carcinogenesis, both through oncogenic activation (MYC, SEMA5A, BCL2L12, RBP2 and BUBR1) and tumor suppressor gene inactivation mechanisms (KLF6, RELN, PTCH1A, CLDN11, and SFRP5). At the level of gastric carcinoma treatment, the HER-2 tyrosine kinase receptor has been demonstrated to be a molecular target of therapy.