Co-transduction of ribosomal protein L23 enhances the therapeutic efficacy of adenoviral-mediated p53 gene transfer in human gastric cancer

Effects of L-Leu-L-Leu peptide on growth, proliferation, and apoptosis in broiler intestinal epithelial cells

Small peptides are nutrients and bioactive molecules that have dual regulatory effects on nutrition and physiology. They are of great significance for maintaining the intestinal health and production performance of broilers. We here cultured the primary small intestinal epithelial cells (IEC) of chicken in a medium containing L-Leu (Leu) and L-Leu-L-Leu (Leu-Leu) for 24 h. The untreated cells were considered as the control group. The growth, proliferation, and apoptosis of IEC were examined. By combining RNA-seq and label-free sequencing technology, candidate genes, proteins, and pathways related to the growth, proliferation, and apoptosis of IEC were screened. Immunofluorescence detection revealed that the purity of the isolated primary IEC was >90%. The Leu-Leu group significantly promoted IEC growth and proliferation and significantly inhibited IEC apoptosis, and the effect was better than those of the Leu and control groups. Using transcriptome sequencing, four candidate genes, CCL20, IL8L1, IL8, and IL6, were screened in the Leu group, and one candidate gene, IL8, was screened in the Leu-Leu group. Two candidate genes, IL6 and RGN, were screened in the Leu-Leu group compared with the Leu group. Nonquantitative proteomic marker sequencing results revealed that through the screening of candidate proteins and pathways, found one growth-related candidate protein PGM3 and three proliferation-related candidate proteins RPS17, RPS11, and RPL23, and two apoptosis-related candidate proteins GPX4 and PDPK1 were found in the Leu-Leu group compared with Leu group. In short, Leu-Leu could promote IEC growth and proliferation and inhibit IEC apoptosis. On combining transcriptome and proteome sequencing technologies, multiple immune- and energy-related regulatory signal pathways were found to be related to IEC growth, proliferation, and apoptosis. Three candidate genes of IL8, IL6, and RGN were identified, and six candidate proteins of PGM3, RPS17, RPS11, RPL23, GPX4, and PDPK1 were involved in IEC growth, proliferation, and apoptosis. The results provide valuable data for preliminarily elucidating small peptide-mediated IEC regulation pathways, improving the small peptide nutrition theoretical system, and establishing small peptide nutrition regulation technology.

Identification of three small nucleolar RNAs (snoRNAs) as potential prognostic markers in diffuse large B-cell lymphoma

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) is a non-Hodgkin lymphoma with high mortality rates. Small nucleolar RNAs (snoRNAs) are tumor-specific biological markers, but there are few studies on the role of snoRNAs in DLBCL.

MATERIALS AND METHODS

Survival-related snoRNAs were selected to construct a specific snoRNA-based signature via computational analyses (Cox regression and independent prognostic analyses) to predict the prognosis of DLBCL patients. To assist in clinical applications, a nomogram was built by combining the risk model and other independent prognostic factors. Pathway analysis, gene ontology analysis, transcription factor enrichment, protein-protein interactions, and single nucleotide variant analysis were used to explore the potential biological mechanisms of co-expressed genes.

RESULTS

Twelve prognosis-correlated snoRNAs were selected from the DLBCL patient cohort of microarray profiles, and a three-snoRNA signature consisting of SNORD1A, SNORA60, and SNORA66 was constructed. DLBCL patients could be divided into high-risk and low-risk cohorts using the risk model, and the high-risk group and activated B cell-like (ABC) type DLBCL were linked with disappointing survival. In addition, SNORD1A co-expressed genes were inseparably linked to the biological functions of the ribosome and mitochondria. Potential transcriptional regulatory networks have also been identified. MYC and RPL10A were the most mutated SNORD1A co-expressed genes in DLBCL.

CONCLUSION

Put together, our findings explored the potential biological effects of snoRNAs in DLBCL, and provided a new predictor for DLBCL prediction.

Overview of the pre-clinical and clinical studies about the use of CAR-T cell therapy of cancer combined with oncolytic viruses

Background

Cancer is one of the critical issues of the global health system with a high mortality rate even with the available therapies, so using novel therapeutic approaches to reduce the mortality rate and increase the quality of life is sensed more than ever.

Main body

CAR-T cell therapy and oncolytic viruses are innovative cancer therapeutic approaches with fewer complications than common treatments such as chemotherapy and radiotherapy and significantly improve the quality of life. Oncolytic viruses can selectively proliferate in the cancer cells and destroy them. The specificity of oncolytic viruses potentially maintains the normal cells and tissues intact. T-cells are genetically manipulated and armed against the specific antigens of the tumor cells in CAR-T cell therapy. Eventually, they are returned to the body and act against the tumor cells. Nowadays, virology and oncology researchers intend to improve the efficacy of immunotherapy by utilizing CAR-T cells in combination with oncolytic viruses.

Conclusion

Using CAR-T cells along with oncolytic viruses can enhance the efficacy of CAR-T cell therapy in destroying the solid tumors, increasing the permeability of the tumor cells for T-cells, reducing the disturbing effects of the immune system, and increasing the success chance in the treatment of this hazardous disease.

In recent years, significant progress has been achieved in using oncolytic viruses alone and in combination with other therapeutic approaches such as CAR-T cell therapy in pre-clinical and clinical investigations. This principle necessitates a deeper consideration of these treatment strategies. This review intends to curtly investigate each of these therapeutic methods, lonely and in combination form. We will also point to the pre-clinical and clinical studies about the use of CAR-T cell therapy combined with oncolytic viruses.

Ribosomal Protein L23 Drives the Metastasis of Hepatocellular Carcinoma via Upregulating MMP9

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths globally. Tumor metastasis is one of the major causes of high mortality of HCC. Identifying underlying key factors contributing to invasion and metastasis is critical to understand the molecular mechanisms of HCC metastasis. Here, we identified RNA binding protein L23 (RPL23) as a tumor metastasis driver in HCC. RPL23 was significantly upregulated in HCC tissues compared to adjacent normal tissues, and closely related to poor clinical outcomes in HCC patients. RPL23 depletion inhibited HCC cell proliferation, migration and invasion, and distant metastasis. Mechanistically, RPL23 directly associated with 3'UTR of MMP9, therefore positively regulated MMP9 expression. In conclusion, we identified that RPL23 might play an important role in HCC metastasis in an MMP9-dependent manner and be a potential therapeutic target for HCC tumorigenesis and metastasis.

Adenovirus vector-attributed hepatotoxicity blocks clinical application in gene therapy

Adenoviruses (Ads), common self-limiting pathogens in humans and animals, usually cause conjunctivitis, mild upper respiratory tract infection or gastroenteritis in humans and hepatotoxicity syndrome in chickens and dogs, posing great threats to public health and livestock husbandry. Artificially modified Ads, which wipe out virulence-determining genes, are the most frequently used viral vectors in gene therapy, and some Ad vector (AdV)-related medicines and vaccines have been licensed and applied. Inherent liver tropism enables AdVs to specifically deliver drugs/genes to the liver; however, AdVs are closely associated with acute hepatotoxicity in immunocompromised individuals, and the side effects of AdVs, which stimulate a strong inflammatory reaction in the liver and cause acute hepatotoxicity, have largely limited clinical application. Therefore, this review systematically elucidates the intimate relationship between AdVs and hepatotoxicity in terms of virus and host and precisely illustrates the accumulated understanding in this field over the past decades. This review demonstrates the liver tropism of AdVs and molecular mechanism of AdV-induced hepatotoxicity and looks at the studies on AdV-mediated animal hepatotoxicity, which will undoubtedly deepen the understanding of AdV-caused liver injury and be of benefit in the further safe development of AdVs.

Ribosome Biogenesis and Cancer: Overview on Ribosomal Proteins

Cytosolic ribosomes (cytoribosomes) are macromolecular ribonucleoprotein complexes that are assembled from ribosomal RNA and ribosomal proteins, which are essential for protein biosynthesis. Mitochondrial ribosomes (mitoribosomes) perform translation of the proteins essential for the oxidative phosphorylation system. The biogenesis of cytoribosomes and mitoribosomes includes ribosomal RNA processing, modification and binding to ribosomal proteins and is assisted by numerous biogenesis factors. This is a major energy-consuming process in the cell and, therefore, is highly coordinated and sensitive to several cellular stressors. In mitochondria, the regulation of mitoribosome biogenesis is essential for cellular respiration, a process linked to cell growth and proliferation. This review briefly overviews the key stages of cytosolic and mitochondrial ribosome biogenesis; summarizes the main steps of ribosome biogenesis alterations occurring during tumorigenesis, highlighting the changes in the expression level of cytosolic ribosomal proteins (CRPs) and mitochondrial ribosomal proteins (MRPs) in different types of tumors; focuses on the currently available information regarding the extra-ribosomal functions of CRPs and MRPs correlated to cancer; and discusses the role of CRPs and MRPs as biomarkers and/or molecular targets in cancer treatment.

Role of heat-shock proteins in infection of human adenocarcinoma cell line MCF-7 by tumor-adapted rotavirus isolates

Background:

Viruses are being used as alternative and complementary tools for treating cancers. Oncolytic viruses exhibit tumor tropism, ability to enhance anti-tumor immunity and ability to be used in combination with conventional chemotherapy and radiotherapy. We have recently selected some rotavirus isolates which are adapted to efficiently infect and kill tumor cell lines.

Aim:

We tested five tumor cell-adapted rotavirus isolates for their ability to infect the human adenocarcinoma cell line MCF-7.

Methods:

Cell surface membrane-associated proteins mediating virus particle attachment were characterized using ELISA, immunoprecipitation, FACS analysis, and antibody blocking.

Results:

It was found that heat shock proteins (HSPs) such as Hsp90, Hsp70, Hsp60, and Hsp40 are expressed on the cell surface forming complexes with protein disulfide isomerase (PDI), integrin β3, and heat shock cognate protein 70 (Hsc70) in lipid raft microdomains. Interaction of rotavirus isolates with these cellular proteins was further confirmed by a competition assay and an inhibition assay involving the HSPs tested.

Conclusion:

Our findings suggest that the tumor cell-adapted rotavirus isolates studied here offer a promising tool for killing tumor cells, thus encouraging further research into this topic, including animal models.

Isoforms of the p53 Family and Gastric Cancer: A Ménage à Trois for an Unfinished Affair

Simple Summary

The p53 family is a complex family of transcription factors with different cellular functions that are involved in several physiological processes. A massive amount of data has been accumulated on their critical role in the tumorigenesis and the aggressiveness of cancers of different origins. If common features are observed, there are numerous specificities that may reflect particularities of the tissues from which the cancers originated. In this regard, gastric cancer tumorigenesis is rather remarkable, as it is induced by bacterial and viral infections, various chemical carcinogens, and familial genetic alterations, which provide an example of the variety of molecular mechanisms responsible for cell transformation and how they impact the p53 family. This review summarizes the knowledge gathered from over 40 years of research on the role of the p53 family in gastric cancer, which still displays one of the most elevated mortality rates amongst all types of cancers.

Abstract

Gastric cancer is one of the most aggressive cancers, with a median survival of 12 months. This illustrates its complexity and the lack of therapeutic options, such as personalized therapy, because predictive markers do not exist. Thus, gastric cancer remains mostly treated with cytotoxic chemotherapies. In addition, less than 20% of patients respond to immunotherapy. TP53 mutations are particularly frequent in gastric cancer (±50% and up to 70% in metastatic) and are considered an early event in the tumorigenic process. Alterations in the expression of other members of the p53 family, i.e., p63 and p73, have also been described. In this context, the role of the members of the p53 family and their isoforms have been investigated over the years, resulting in conflicting data. For instance, whether mutations of TP53 or the dysregulation of its homologs may represent biomarkers for aggressivity or response to therapy still remains a matter of debate. This uncertainty illustrates the lack of information on the molecular pathways involving the p53 family in gastric cancer. In this review, we summarize and discuss the most relevant molecular and clinical data on the role of the p53 family in gastric cancer and enumerate potential therapeutic innovative strategies.

Viral Vector-Based Melanoma Gene Therapy

Gene therapy applications of oncolytic viruses represent an attractive alternative for cancer treatment. A broad range of oncolytic viruses, including adenoviruses, adeno-associated viruses, alphaviruses, herpes simplex viruses, retroviruses, lentiviruses, rhabdoviruses, reoviruses, measles virus, Newcastle disease virus, picornaviruses and poxviruses, have been used in diverse preclinical and clinical studies for the treatment of various diseases, including colon, head-and-neck, prostate and breast cancer as well as squamous cell carcinoma and glioma. The majority of studies have focused on immunotherapy and several drugs based on viral vectors have been approved. However, gene therapy for malignant melanoma based on viral vectors has not been utilized to its full potential yet. This review represents a summary of the achievements of preclinical and clinical studies using viral vectors, with the focus on malignant melanoma.

Guerrero C, Acosta O. Role of heat-shock proteins in infection of human adenocarcinoma cell line MCF-7 by tumor-adapted rotavirus isolates

Background: Viruses are being used as alternative and complementary tools for treating cancers. Oncolytic viruses exhibit tumor tropism, ability to enhance anti-tumor immunity and ability to be used in combination with conventional chemotherapy and radiotherapy. We have recently selected some rotavirus isolates which are adapted to efficiently infect and kill tumor cell lines. Aim: We tested five tumor cell-adapted rotavirus isolates for their ability to infect the human adenocarcinoma cell line MCF-7. Methods: Cell surface membrane-associated proteins mediating virus particle attachment were characterized using ELISA, immunoprecipitation, FACS analysis, and antibody blocking. Results: It was found that heat shock proteins (HSPs) such as Hsp90, Hsp70, Hsp60, and Hsp40 are expressed on the cell surface forming complexes with protein disulfide isomerase (PDI), integrin β3, and heat shock cognate protein 70 (Hsc70) in lipid raft microdomains. Interaction of rotavirus isolates with these cellular proteins was further confirmed by a competition assay and an inhibition assay involving the HSPs tested. Conclusion: Our findings suggest that the tumor cell-adapted rotavirus isolates studied here offer a promising tool for killing tumor cells, thus encouraging further research into this topic, including animal models.

Oncolytic adenoviruses: a game changer approach in the battle between cancer and the immune system

INTRODUCTION

Oncolytic adenoviruses are among the most studied oncolytic viruses because of their tumor selectivity, safety, and transgene-delivery capability. With a growing number of different immunotherapies against cancer, the extraordinary immunogenicity of the adenovirus has emerged as a differentiating strength. Enabling T-cell related therapies with oncolytic adenoviruses appears a promising approach due to its inherent ability to elicit responses from the adaptive immune compartment.

AREAS COVERED

These viruses have successfully enhanced both adoptive T-cell therapies and immune-checkpoint therapies. Oncolytic viruses induce several effects at the tumor and on the systemic level that help to circumvent current limitations of T-cells and related therapies, such as T-cell trafficking, tumor immune suppressivity and antigen spreading

EXPERT OPINION

Taking into account the multitude of possibilities of treating cancer with immunotherapies, learning to optimize the combinations and administration strategies of these drugs, could lead to durable responses in patients with currently incurable cancers.

Quercetin Inhibits the Proliferation and Aflatoxins Biosynthesis of Aspergillus flavus

In this work of quercetin’s anti-proliferation action on A. flavus, we revealed that quercetin can effectively hamper the proliferation of A. flavus in dose-effect and time-effect relationships. We tested whether quercetin induced apoptosis in A. flavus via various detection methods, such as phosphatidylserine externalization and Hoechst 33342 staining. The results showed that quercetin had no effect on phosphatidylserine externalization and cell nucleus in A. flavus. Simultaneously, quercetin reduced the levels of reactive oxygen species (ROS). For a better understanding of the molecular mechanism of the A. flavus response to quercetin, the RNA-Seq was used to explore the transcriptomic profiles of A. flavus. According to transcriptome sequencing data, quercetin inhibits the proliferation and aflatoxin biosynthesis by regulating the expression of development-related genes and aflatoxin production-related genes. These results will provide some theoretical basis for quercetin as an anti-mildew agent resource.

The roles of moonlight ribosomal proteins in the development of human cancers

"Moonlighting protein" is a term used to define a single protein with multiple functions and different activities that are not derived from gene fusions, multiple RNA splicing, or the proteolytic activity of promiscuous enzymes. Different proteinous constituents of ribosomes have been shown to have important moonlighting extra-ribosomal functions. In this review, we introduce the impact of key moonlight ribosomal proteins and dependent signal transduction in the initiation and progression of various cancers. As a future perspective, the potential role of these moonlight ribosomal proteins in the diagnosis, prognosis, and development of novel strategies to improve the efficacy of therapies for human cancers has been suggested.

Pembrolizumab for the treatment of gastric cancer

INTRODUCTION

Gastric cancer is one of a few gastrointestinal malignancies in which immunotherapy has shown meaningful activity. Pembrolizumab is the first and only immune checkpoint inhibitor to be FDA-approved in gastric cancer. Areas Covered: This review summarizes the current and emerging clinical evidence for immune checkpoint inhibitors in advanced and metastatic gastric cancer, with a focus on pembrolizumab. Expert Commentary: Pembrolizumab has shown impressive activity in the third-line treatment of locally advanced and metastatic gastric cancer. It is currently being studied as upfront therapy in combination with chemotherapy. The emerging understanding of the molecular alterations and tumor immune microenvironment as predictors of immunotherapy response in gastric cancer are discussed. The impact of gastric mucosal dysbiosis on gastric carcinogenesis and the modulation of immunotherapy response by the gut microbiome are also reviewed.

New frontiers in oncolytic viruses: optimizing and selecting for virus strains with improved efficacy

Oncolytic viruses have demonstrated selective replication and killing of tumor cells. Different types of oncolytic viruses – adenoviruses, alphaviruses, herpes simplex viruses, Newcastle disease viruses, rhabdoviruses, Coxsackie viruses, and vaccinia viruses – have been applied as either naturally occurring or engineered vectors. Numerous studies in animal-tumor models have demonstrated substantial tumor regression and prolonged survival rates. Moreover, clinical trials have confirmed good safety profiles and therapeutic efficacy for oncolytic viruses. Most encouragingly, the first cancer gene-therapy drug – Gendicine, based on oncolytic adenovirus type 5 – was approved in China. Likewise, a second-generation oncolytic herpes simplex virus-based drug for the treatment of melanoma has been registered in the US and Europe as talimogene laherparepvec.

Glutamate-rich WD40 repeat containing 1 regulates ribosomal protein L23 levels via the ubiquitin-proteasome system

GRWD1 is a Cdt1-binding protein that promotes MCM loading through its histone chaperone activity. GRWD1 acts as a tumor-promoting factor by downregulating p53 via the RPL11-MDM2-p53 axis. Here, we identified GRWD1-interacting proteins using a proteomics approach and showed that GRWD1 interacts with various proteins involved in transcription, translation, DNA replication and repair, chromatin organization, and ubiquitin-mediated proteolysis. We focused on the ribosomal protein RPL23, which positively regulates nucleolar stress responses through MDM2 binding and inhibition, thereby functioning as a tumor suppressor. Overexpression of GRWD1 decreased RPL23 protein levels and stability; this effect was restored by the proteasome inhibitor MG132. EDD, an E3 ubiquitin ligase that interacts with GRWD1, also downregulated RPL23, and the decrease was further enhanced by co-expression of GRWD1. Conversely, siRNA-mediated GRWD1 knockdown upregulated RPL23. Co-expression of GRWD1 and EDD promoted RPL23 ubiquitination. These data suggest that GRWD1 acts together with EDD to negatively regulate RPL23 via the ubiquitin-proteasome system. GRWD1 reversed the RPL23-mediated inhibition of anchorage-independent growth in cancer cells. Our data suggest that GRWD1-induced RPL23 proteolysis plays a role in p53 downregulation and tumorigenesis.

Latest trends in cancer therapy applying viral vectors

Gene therapy based on viral vectors has demonstrated steady progress recently, not only in the area of cancers. A multitude of viral vectors has been engineered for both preventive and therapeutic applications. Two main approaches comprise of viral vector-based delivery of toxic or anticancer genes or immunization with anticancer antigens. Tumor growth inhibition and tumor regression have been observed, providing improved survival rates in animal tumor models. Furthermore, vaccine-based cancer immunotherapy has demonstrated both tumor regression and protection against challenges with lethal doses of tumor cells. Several clinical trials with viral vectors have also been conducted. Additionally, viral vector-based cancer drugs have been approved. This review gives an overview of different viral vector systems and their applications in cancer gene therapy.

Transcriptomic profiling of long non-coding RNAs in hepatitis B virus-related hepatocellular carcinoma

Long non-coding RNAs (lncRNAs) have been reported to be involved in the development and progression of hepatocellular carcinoma (HCC). However, few studies have focus on the dyregulation and the role of lncRNAs in HBV-related HCC. We performed a comprehensive analysis of lncRNAs expression profile in HBV-related HCC tissues samples using deep sequencing. We revealed that a total of 1242 lncRNA transcripts (983 up-regulated and 259 down-regulated) and 1841 mRNA transcripts were significantly differentially expressed in HBV-related HCC patients. Pathway and gene ontology analysis showed that they are involved in the biological process related to HCC development by cis-regulation of co-expressed protein-coding genes. 10 candidate lncRNAs were selected and validated with quantitative real-time PCR analysis. Furthermore, we found that one of most down-regulated lncRNAs, n346077, could suppress HCC cells invasion and migration in vitro. Our findings provide an overview of aberrantly expressed lncRNAs in HBV-related HCC and will be useful for further functional studies of lncRNAs in HBV-related pathogenesis.

Ribosomal protein L23 negatively regulates cellular apoptosis via the RPL23/Miz-1/c-Myc circuit in higher-risk myelodysplastic syndrome

Ribosomal protein (RP) L23 is a negative regulator of cellular apoptosis, and RPL23 overexpression is associated with abnormal apoptotic resistance in CD34+ cells derived from patients with higher-risk myelodysplastic syndrome (MDS). However, the mechanism underlying RPL23-induced apoptotic resistance in higher-risk MDS patients is poorly understood. In this study, we showed that reduced RPL23 expression led to suppressed cellular viability, increased apoptosis and G1-S cell cycle arrest. Gene microarray analysis comparing RPL23-knockdown and control cells identified an array of differentially expressed genes, of which, Miz-1, was upregulated with transactivation of the cell cycle inhibitors p15^Ink4b and p21^Cip1, and Miz-1’s functional repressor, c-Myc, was downregulated. Cells derived from higher-risk MDS patients demonstrated consistently increased expression of RPL23 and c-Myc and decreased Miz-1 expression compared with cells from lower-risk patients. In conclusion, Miz-1-dependent induction of p15^Ink4b and p21^Cip1 was depressed with decreased Miz-1 and increased c-Myc expression under conditions of elevated RPL23 expression, leading to apoptotic resistance in higher-risk MDS patients. Because RPL23 is encoded by a target gene of c-Myc, the RPL23/Miz-1/c-Myc regulatory circuit provides a feedback loop that links efficient RPL23 expression with c-Myc’s function to suppress Miz-1-induced Cdk inhibitors and thereby leads to apoptotic resistance in higher-risk MDS patients.

Clinical significance of expression of murine double minute 2 and ribosomal protein L23 in gastric cancer

AIM: To detect the expression of murine double minute 2 (MDM2) and ribosomal protein L23 (RPL23) in gastric cancer and explore their biological significance in the development of gastric cancer.

METHODS: The expression of MDM2 and RPL23 was detected by immunohistochemistry in 90 human gastric carcinoma specimens and 30 normal gastric tissue specimens. The correlation of MDM2 and RPL23 expression with the clinicopathologic features of gastric carcinoma was analyzed statistically.

RESULTS: The positive expression rate of MDM2 in gastric cancer tissues was significantly higher than that in the control group (62.2% vs 40%, P < 0.05), while the positive rate of RPL23 expression was significantly lower in gastric cancer tissues (30% vs 63.3%, P < 0.05). The expression of MDM2 and RPL23 in gastric cancer was negatively correlated (r = -0.23, P = 0.029). Multivariate analysis showed that overexpression of MDM2, low expression of RPL23, lymph node metastasis, depth of invasion and tumor size were significant prognostic factors.

CONCLUSION: MDM2 and RPL23 expression may be associated with the development of gastric cancer, and they may be used as prognostic markers and new therapeutic targets in gastric cancer.

Arsenic sulfide, the main component of realgar, a traditional Chinese medicine, induces apoptosis of gastric cancer cells in vitro and in vivo

Background

Arsenic sulfide (As₄S₄), the main component of realgar, a traditional Chinese medicine, has shown antitumor efficacy in several tumor types, especially for acute promyelocytic leukemia. In this study, we aimed to explore the efficacy and mechanism of As₄S₄ in gastric cancer.

Methods

The effect of As₄S₄ on cell proliferation and apoptosis of gastric cancer cells was investigated by MTT assay, 4′,6-diamidino-2-phenylindole (DAPI) staining, and annexin V–fluorescein isothiocyanate/propidium iodide staining using gastric cancer cell lines AGS (harboring wild-type p53) and MGC803 (harboring mutant p53) in vitro. The expression of apoptosis-related proteins was measured by Western blotting, real-time polymerase chain reaction, and immunohistochemistry analysis. Mouse xenograft models were established by inoculation with MGC803 cells, and the morphology and the proportion of apoptotic cells in tumor tissues were detected by hematoxylin and eosin staining and TdT-mediated dUTP nick end labeling (TUNEL) assay, respectively.

Results

As₄S₄ inhibited the proliferation and induced apoptosis of AGS and MGC803 cells in a time- and dose-dependent manner. As₄S₄ upregulated the expression of Bax and MDM2 while downregulated the expression of Bcl-2. The expression of p53 increased significantly in the AGS cells but did not readily increase in the MGC803 cells, which harbored mutant p53. Pifithrin-α, a p53 inhibitor, blocked the modulation of As₄S₄ on AGS cells, but not on MGC803 cells. Using xenograft as a model, we showed that As₄S₄ suppressed tumor growth and induced apoptosis in vivo and that the expression of p53 increased accordingly.

Conclusion

As₄S₄ is a potent cytotoxic agent for gastric cancer cells, as it induced apoptosis both in vitro and in vivo through a p53-dependent pathway. Our data indicate that As₄S₄ may have therapeutic potential in gastric cancer.

Clinical utility of recombinant adenoviral human p53 gene therapy: current perspectives

Gene therapy has promised to be a highly effective antitumor treatment by introducing a tumor suppressor gene or the abrogation of an oncogene. Among the potential therapeutic transgenes, the tumor suppressor gene p53 serves as an attractive target. Restoration of wild-type p53 function in tumors can be achieved by introduction of an intact complementary deoxyribonucleic acid copy of the p53 gene using a suitable viral vector, in most cases an adenoviral vector (Adp53). Preclinical in vitro and in vivo studies have shown that Adp53 triggers a dramatic tumor regression response in various cancers. These viruses are engineered to lack certain early proteins and are thus replication defective, including Gendicine, SCH-58500, and Advexin. Several types of tumor-specific p53-expressing conditionally replicating adenovirus vectors (known as replication-competent CRAdp53 vectors) have been developed, such as ONYX 015, AdDelta24-p53, SG600-p53, OBP-702, and H101. Various clinical trials have been conducted to investigate the safety and efficiency of these adenoviral vectors. In this review we will talk about the biological mechanisms, clinical utility, and therapeutic potentials of the replication-deficient Adp53-based and replication-competent CRAdp53-based gene therapy.