Role of BAX for outcome prediction in gastrointestinal malignancies

Tumor biomarkers for diagnosis, prognosis and targeted therapy

Tumor biomarkers, the substances which are produced by tumors or the body's responses to tumors during tumorigenesis and progression, have been demonstrated to possess critical and encouraging value in screening and early diagnosis, prognosis prediction, recurrence detection, and therapeutic efficacy monitoring of cancers. Over the past decades, continuous progress has been made in exploring and discovering novel, sensitive, specific, and accurate tumor biomarkers, which has significantly promoted personalized medicine and improved the outcomes of cancer patients, especially advances in molecular biology technologies developed for the detection of tumor biomarkers. Herein, we summarize the discovery and development of tumor biomarkers, including the history of tumor biomarkers, the conventional and innovative technologies used for biomarker discovery and detection, the classification of tumor biomarkers based on tissue origins, and the application of tumor biomarkers in clinical cancer management. In particular, we highlight the recent advancements in biomarker-based anticancer-targeted therapies which are emerging as breakthroughs and promising cancer therapeutic strategies. We also discuss limitations and challenges that need to be addressed and provide insights and perspectives to turn challenges into opportunities in this field. Collectively, the discovery and application of multiple tumor biomarkers emphasized in this review may provide guidance on improved precision medicine, broaden horizons in future research directions, and expedite the clinical classification of cancer patients according to their molecular biomarkers rather than organs of origin.

Up-regulation of peroxiredoxin-1 promotes cell proliferation and metastasis and inhibits apoptosis in cervical cancer

Objective: To investigate the effect of peroxiredoxin 1 (PRDX1) on the biological behavior of cervical cancer cells and the possible mechanism. Materials and methods: The expression of PRDX1 in human cervical cancer tissues and adjacent non-tumor tissues were detected by immunohistochemistry (IHC). Lentivirus containing PRDX1-cDNA or shRNA against PRDX1 was constructed to overexpress or knockdown PRDX1 in SiHa cervical cancer cells. Cell proliferation was tested by CCK-8 and BrdU incorporation assay and cell apoptosis was evaluated by AnnexinV-PE /7AAD assay. Scratch wound and transwell invasion assay were used to test migration and invasion activity after PRDX1 was overexpressed or suppressed. Furthermore, the effect of PRDX1 on cell proliferation and apoptosis was also studied using a xenograft model of nude mice. Results: The expression of PRDX1 protein was significantly up-regulated in the tumor tissues compared with the paired adjacent non-tumor tissues. Meanwhile, PRDX1 overexpression was associated with tumor stage, lymphatic metastasis and differentiation. Overexpression of PRDX1 significantly promoted proliferation and inhibited apoptosis by increasing the expression of Nanog, proliferating cell nuclear antigen (PCNA), B-cell lymphoma-2 (Bcl-2) and downregulating the expression of Bcl2-associated X protein (BAX) in SiHa cervical cancer cells. Moreover, PRDX1 overexpression increased invasion and migration of SiHa cervical cancer cells via up-regulating the expression of Snail and matrix metalloprotein 9 (MMP-9) and down-regulating the expression of E-cadherin. Knockdown of PRDX1 resulted in the opposite results. The role of PRDX1 in promoting SiHa cervical cancer cell proliferation and inhibiting apoptosis has also been confirmed in vivo in a mouse xenograft model. Conclusions: PRDX1 promoted cell proliferation, migration, and invasion and suppressed apoptosis of cervical cancer possibly via regulating the expression of related protein.

Correlation study of GAPDH, Bcl-2, and Bax protein immunoexpression in patients with colorectal adenocarcinoma

Introduction

Colorectal cancer (CRC) is the third and second most commonly diagnosed cancer worldwide in males and females, respectively. Despite prominent progress in diagnosis and treatment, the recurrence rates are still high. A tumour hypoxic environment leads to an increase in glycolytic metabolism. The crucial intermediate component of glycolysis, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), could play a significant role in cancer progression. An increased level of GAPDH has been described in oncogene-induced transformation and anti-apoptotic function. In other studies, GAPDH has been involved in apoptosis induction.

Aim

We examined colorectal adenocarcinoma samples to assess the immunoexpression of GAPDH protein. We also evaluated the correlation between the expression of GAPDH protein and apoptotic parameters including expression of Bcl2 and Bax.

Material and methods

Paraffin sections were incubated for 60 min with primary antibody against GAPDH, Bcl-2, and Bax.

Results

Results of our study have shown that GAPDH expression in colorectal cancer is upregulated. We revealed significant positive correlation between expression of this protein and grade and size of tumour, and regional lymph node involvement. In the case of apoptosis-associated proteins, e.g. Bcl-2 and Bax, we found negative correlations between expression of these proteins and grade and size of tumour, lymphovascular invasion, and regional lymph node involvement. Finally, we demonstrated that GAPDH up-regulation is connected with down-regulation in Bcl-2 and Bax.

Conclusions

Up-regulation of GAPDH protein and down-regulation of Bcl-2 and Bax may result in increased of cancer.

Bax is involved in the anticancer activity of Velcade in colorectal cancer

Numerous chemotherapeutic agents promote tumor cell death by activating the intrinsic apoptosis signaling pathway. This pathway is regulated by mitochondrial dysfunction, which occurs through an intricate process controlled by complex interactions between B-cell lymphoma 2 (Bcl-2) family members and other cellular proteins. Bcl-2-associated X protein (Bax) is a proapoptotic protein that is an essential component of the intrinsic apoptosis signaling pathway. Patients lacking Bax may be less sensitive to chemotherapy due to an impaired intrinsic apoptosis signaling pathway. The present study demonstrated that Bax expression in colorectal cancer (CRC) tissues was typically increased compared with that in adjacent normal tissues. Furthermore, Bax^-/- HCT-116 cells exhibited reduced proliferation and colony formation ability compared with Bax^+/+ HCT116 cells, although the rate of apoptosis of these cells remained unchanged. However, Bax^-/- HCT116 cells became more resistant to apoptosis when treated with Velcade. The results of the present study provide novel insights into the relevance of Bax expression to the prognosis of CRC.

A Study of Gene Expression of Survivin, its Antiapoptotic Variants, and Targeting Survivin In Vitro for Therapy in Retinoblastoma

Apoptosis is a natural process regulated by apoptotic and antiapoptotic molecules. We investigated mRNA expression of survivin and its splice variants, along with B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X (Bax), in a cohort of 20 retinoblastoma (RB) tumors by real-time polymerase chain reaction. We hypothesized a correlation between the Bcl-2/Bax and survivin splice variants and also that expression of these would be associated with clinicopathologic features of tumors. The Bcl-2 expression was significantly higher (P<0.001) in RB, and Bcl-2/Bax ratio was remarkably higher in poorly differentiated tumors. A statistically significant higher expression of Survivin-WT (wild type) compared with its variant Survivin-2β (P<0.05) was observed. Bcl-2 did not exhibit positive correlation with any of the survivin variants except Survivin-2β, whereas Bax exhibited significant (P<0.05) correlation with the variants. Thus, it could be suggested that a superior player out of a likely interaction between the variants and Bcl-2/Bax uses its activity for the progression of RB. Silencing of Survivin-WT in the Y79 cell line was studied by siRNA technology and cell-permeable dominant negative survivin (SurR9-C84A). siRNA showed higher proapoptotic effects and increased caspase 3/7 activity in Y79 cells. Effective internalization of SurR9-C84A in Y79 cells induced cytotoxic effects. Thus, the current study confirms survivin as a promising target for therapy.

Emerging role of N-myc downstream-regulated gene 2 (NDRG2) in cancer

N-myc downstream-regulated gene 2 (NDRG2) is a tumor suppressor and cell stress-related gene. NDRG2 is associated with tumor incidence, progression, and metastasis. NDRG2 regulates tumor-associated genes and is regulated by multiple conditions, treatments, and protein/RNA entities, including hyperthermia, trichostatin A and 5-aza-2'-deoxycytidine, which are promising potential cancer therapeutics. In this review, we discuss the expression as well as the clinical and pathological significance of NDRG2 in cancer. The pathological processes and molecular pathways regulated by NDRG2 are also summarized. Moreover, mechanisms for increasing NDRG2 expression in tumors and the potential directions of future NDRG2 research are discussed. The information reviewed here should assist in experimental design and increase the potential of NDRG2 as a therapeutic target for cancer.

Activation of Toll-like receptor 7 inhibits the proliferation and migration, and induces the apoptosis of pancreatic cancer cells

Pancreatic cancer is one of the most malignant types of tumor and has a poor prognosis. Toll‑like receptor 7 (TLR7) has been found to be present and have different roles in different types of cancer cells. In the present study, the roles of TLR7 in BxPC‑3 cells, a human pancreatic adenocarcinoma cell line, were investigated. The cells were treated with gardiquimod, an agonist of TLR7, following which the properties of the cells, including proliferation, migration, cell cycle and apoptosis, were analyzed. It was revealed that activation of TLR7 by gardiquimod inhibited cell proliferation and migration, and induced apoptosis of the cells. In addition, gardiquimod downregulated the expression levels of cyclin B1, cyclin E and B‑cell lymphoma 2, while upregulating the expression of B‑cell‑associated X protein. These results suggested that the activation of TLR7 suppresses the progression of pancreatic cancer.

BAX and CDKN1A polymorphisms correlated with clinical outcomes of gastric cancer patients treated with postoperative chemotherapy

This study aims to examine the correlation between two single nucleotide polymorphisms (SNPs) of apoptosis-related genes and clinical outcomes in gastric cancer. A total of 221 patients with stage T2 and T3 gastric cancer treated with postoperative chemotherapy between 2003 and 2008 were retrospectively collected in this study to explore the association of rs4645878 located in BAX gene and rs1801270 located in CDKN1A gene with survival, recurrence, and toxicity to chemotherapy. Additionally, immunohistochemistry was used to detect the BAX expression in gastric cancer tissues. Patients carrying at least one variant genotype in BAX SNP (rs4645878) showed a significantly increased recurrence risk [hazard ratio (HR) 2.63; 95 % confidence internal (95 % CI) 1.71-4.03] and poor survival (HR 2.89; 95 % CI 1.88-4.44). Moreover, the recurrence and survival rate in patients with GA genotype was 72.7 and 24.7 %, respectively, compared with total recurrence rate of 54.8 %, P = 0.006, and compared with total survival rate of 46.6 %, P = 0.001. In addition, the GA genotype was related to lower BAX expression in gastric cancer tissues. The CDKN1A (rs1801270) mutant genotype was associated with a significantly decreased risk of hematologic toxicity [odds ratio (OR) 0.28; 95 % CI 0.12-0.63]. SNPs located in BAX and CDKN1A genes are closely associated with clinical outcomes in patients with gastric cancer.