Adenovirus-mediated IL-24 expression enhances the chemosensitivity of multidrug-resistantgastric cancer cells to cisplatin

Role of Interleukins and New Perspectives in Mechanisms of Resistance to Chemotherapy in Gastric Cancer

Gastric cancer (GC) is the fourth most common cancer in the world in terms of incidence and second in terms of mortality. Chemotherapy is the main treatment for GC. The greatest challenge and major cause of GC treatment failure is resistance to chemotherapy. As such, research is ongoing into molecular evaluation, investigating mechanisms, and screening therapeutic targets. Several mechanisms related to both the tumor cells and the tumor microenvironment (TME) are involved in resistance to chemotherapy. TME promotes the secretion of various inflammatory cytokines. Recent studies have revealed that inflammatory cytokines affect not only tumor growth, but also chemoresistance. Cytokines in TME can be detected in blood circulation and TME cells. Inflammatory cytokines could serve as potential biomarkers in the assessment of chemoresistance and influence the management of therapeutics in GC. This review presents recent data concerning research on inflammatory cytokines involved in the mechanisms of chemoresistance and provides new clues in GC treatment.

Salinomycin reduces epithelial-mesenchymal transition-mediated multidrug resistance by modifying long noncoding RNA HOTTIP expression in gastric cancer cells

Chemotherapy is the main treatment for advanced gastric cancer. However, the emergence of multidrug resistance (MDR) has become a major obstacle in chemotherapy in many tumors, including gastric cancer. Epithelial-mesenchymal transition (EMT), which is considered an important process in cancer development, also contributes toward tumor MDR. Salinomycin, an EMT blocker, shows broad-spectrum antitumor and chemosensitization properties. Here, we hypothesized that salinomycin could reverse the MDR of SGC7901/cisplatin (CDDP) gastric cancer cell by inhibiting EMT and further explored its possible underlying mechanisms. Our results indicated higher 50% inhibiting concentration (IC50) and stronger migration capacity in SGC7901/CDDP than in SGC7901 cells, whereas salinomycin could reduce the IC50 (50% inhibition of the concentration of chemodrugs after 4 μmol/l salinomycin treatment) and migration capacity in SGC7901/CDDP cells. At the molecular level, we found that the expression of E-cadherin, ZO-1 decreased, whereas the expression of N-cadherin, Vimentin, ZEB-1, and Twist increased in SGC7901/CDDP cells, and that salinomycin potently blocked the EMT by enhancing the expression of E-cadherin, ZO-1 and reducing the expression of N-cadherin, Vimentin, ZEB-1, and Twist in the above MDR cells. In addition, we also found that long noncoding RNA HOTTIP, an oncogenic regulator, was upregulated in SGC7901/CDDP cells, whereas its downregulation could markedly attenuate the EMT, thereby reversing the MDR. Furthermore, our data showed that the salinomycin-elicited MDR-reversion effect was associated closely with suppression of EMT through inhibition of the expression of long noncoding RNA HOTTIP. Collectively, our findings suggest a new underlying mechanism and applicable therapeutic regimen for MDR gastric cancer.

A Review of Research Progress in Multidrug-Resistance Mechanisms in Gastric Cancer

Gastric cancer is one of the most common malignant tumors, and it is also one of the leading causes of cancer death worldwide. Because of its insidious symptoms and lack of early dictation screening, many cases of gastric cancer are at late stages which make it more complicated to cure. For these advanced-stage gastric cancers, combination therapy of surgery, chemotherapy, radiotherapy and target therapy would bring more benefit to the patients. However, the drug-resistance to the chemotherapy restricts its effect and might lead to treatment failure. In this review article, we discuss the mechanisms which have been found in recent years of drug resistance in gastric cancer. And we also want to find new approaches to counteract chemotherapy resistance and bring more benefits to the patients.

The Interleukin-20 Cytokines in Intestinal Diseases

Autoimmune/inflammatory intestinal diseases, such as Crohn’s disease and ulcerative colitis, infectious gastrointestinal diseases, and gastrointestinal cancers, such as colorectal cancer, are worldwide a significant health problem. Intercellular communication and direct contact with the environment as the microbiota colonizes the gastrointestinal surface facilitates these diseases. Cytokines mediate the intercellular communication to maintain the equilibrium between host and environment and to regulate immune responses. One cytokine family that exchange information between immune cells and epithelial cells is the IL-20 cytokine family which includes the cytokines IL-19, IL-20, IL-22, IL-24, and IL-26. These cytokines share common receptor subunits and signaling pathways. IL-22 is the most intensively studied cytokine within this family in contexts of gastrointestinal disease, but the importance of other family members is more and more appreciated. In this review, the potential function of IL-20 cytokines concerning gastrointestinal conditions is discussed.

Reversal effect of adenovirus-mediated human interleukin 24 transfection on the cisplatin resistance of A549/DDP lung cancer cells

Interleukin-24 (IL-24) is a tumor-suppressor gene that has been documented in human melanoma cells. IL-24 has marked antitumor activities on various types of human cancer, but its underlying mechanism remains unclear. In the present, we investigated the effects of human IL-24 (hIL-24) on the chemotherapy resistance of lung cancer cells. The cisplatin (DDP)-resistant lung carcinoma cell line A549/DDP was subjected to adenovirus-mediated transfection with the human IL-24 gene (Ad-hIL-24). The growth-inhibitory and apoptotic effects of Ad-hIL-24 on A549/DDP cells were observed, and the expression levels of AKT, phosphorylated-AKT (p-AKT) and P-glycoprotein (P-gp) were detected. Ad-hIL-24 significantly decreased the levels of p-AKT and P-gp, and effectively inhibited A549/DDP cell growth. Furthermore, A549/DDP cells exhibited a significantly increased rate of apoptosis, as well as G2/M-phase arrest, following transfection with Ad-hIL-24, and these effects were increased in cells treated with Ad-IL-24 combined with DDP when compared with those treated with Ad-hIL-24 or DDP alone. These results suggest that hIL-24 can reverse the DDP resistance of lung cancer cells, and that the associated mechanism involves the induction of apoptosis and G2/M-phase arrest through the phosphoinositide3-kinase (PI3K)/AKT signaling pathway, as well as a decrease in drug resistance through P-gp expression.

Oncolytic adenovirus‑mediated mda‑7/IL‑24 expression suppresses osteosarcoma growth and enhances sensitivity to doxorubicin

Osteosarcoma (OS) is a malignant disease with a high mortality rate and poor response to current chemotherapy. Melanoma differentiation associated gene‑7 (Mda7)/interleukin (IL)‑24 has been demonstrated to suppress the growth of OS. However, the expression level of Mda7/IL‑24 mediated by the current adenoviral vector is limited for effective clinical treatment of OS. In order to solve this issue, an oncolytic adenovirus was employed to express IL‑24 (OA‑IL‑24) in OS cells. Quantitative polymerase chain reaction, immunoblot and ELISA assays verified that OA‑IL‑24 expressed IL‑24 at a higher level than the replication‑deficient adenoviral vector, Ad‑IL24. OA‑IL‑24 infection led to decreased cell viability and increased apoptosis of OS cells, compared with Ad‑IL‑24. Animal studies further confirmed the increased anti‑tumor activity of OA‑IL‑24. Notably, OA‑IL‑24 was also found to sensitize OS cells to doxorubicin. OA‑IL‑24‑induced multiple drug resistance reversion was associated with reduced expression of Pgp and BCRP1, as well as minimized autophagy. Furthermore, restoring Pgp and BCRP1 expression as well as autophagy, was able to rescue the effect of IL‑24 on the cytotoxicity of doxorubicin to OS. In conclusion, a method for inducing a high expression of IL‑24 in OS was provided. In addition, IL‑24 was demonstrated to increase the sensitivity of OS to doxorubicin.

CSBF/C10orf99, a novel potential cytokine, inhibits colon cancer cell growth through inducing G1 arrest

Cytokines are soluble proteins that exert their functions by binding specific receptors. Many cytokines play essential roles in carcinogenesis and have been developed for the treatment of cancer. In this study, we identified a novel potential cytokine using immunogenomics designated colon-derived SUSD2 binding factor (CSBF), also known as chromosome 10 open reading frame 99 (C10orf99). CSBF/C10orf99 is a classical secreted protein with predicted molecular mass of 6.5 kDa, and a functional ligand of Sushi Domain Containing 2 (SUSD2). CSBF/C10orf99 has the highest expression level in colon tissue. Both CSBF/C10orf99 and SUSD2 are down-regulated in colon cancer tissues and cell lines with different regulation mechanisms. CSBF/C10orf99 interacts with SUSD2 to inhibit colon cancer cell growth and induce G1 cell cycle arrest by down-regulating cyclin D and cyclin-dependent kinase 6 (CDK6). CSBF/C10orf99 displays a bell-shaped activity curve with the optimal effect at ~10 ng/ml. Its growth inhibitory effects can be blocked by sSUSD2-Fc soluble protein. Our results suggest that CSBF/C10orf99 is a novel potential cytokine with tumor suppressor functions.

Molecular targets and signaling pathways regulated by interleukin (IL)-24 in mediating its antitumor activities

Cancer remains a major health issue in the world and the effectiveness of current therapies is limited resulting in disease recurrence and resistance to therapy. Therefore to overcome disease recurrence and have improved treatment efficacy there is a continued effort to develop and test new anticancer drugs that are natural or synthetic - (conventional chemotherapeutics, small molecule inhibitors) and biologic (antibody, tumor suppressor genes, oligonucleotide) product. In parallel, efforts for identifying molecular targets and signaling pathways to which cancer cells are "addicted" are underway. By inhibiting critical signaling pathways that is crucial for cancer cell survival, it is expected that the cancer cells will undergo a withdrawal symptom akin to "de-addiction" resulting in cell death. Thus, the key for having an improved and greater control on tumor growth and metastasis is to develop a therapeutic that is able to kill tumor cells efficiently by modulating critical signaling pathways on which cancer cells rely for their survival.Currently several small molecule inhibitors targeted towards unique molecular signaling pathways have been developed and tested in the clinic. Few of these inhibitors have shown efficacy while others have failed. Thus, targeting a single molecule or pathway may be insufficient to completely block cancer cell proliferation and survival. It is therefore important to identify and test an anticancer drug that can inhibit multiple signaling pathways in a cancer cell, control growth of both primary and metastatic tumors and is safe.One biologic agent that has the characteristics of serving as a potent anticancer drug is interleukin (IL)-24. IL-24 suppresses multiple signaling pathways in a broad-spectrum of human cancer cells leading to tumor cell death, inhibition of tumor angiogenesis and metastasis. Additionally, combining IL-24 with other therapies demonstrated additive to synergistic antitumor activity. Clinical testing of IL-24 as a gene-based therapeutic for the treatment of solid tumors demonstrated that IL-24 is efficacious and is safe. The unique features of IL-24 support its further development as an anticancer drug for cancer treatment.In this review we summarize the current understanding on the molecular targets and signaling pathways regulated by IL-24 in mediating its anticancer activity.