Paclitaxel enhances tumoricidal potential of TRAIL via inhibition of MAPK in resistant gastric cancer cells

Death receptor 5 promotes tumor progression in gastric cancer

Death receptor 5 (DR5) can inhibit malignant proliferation via tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in many cancers. Here we examined the expression and sublocalization of DR5 in gastric cancer, as well as its effects on clinical prognosis and cellular processes. Our analysis included a cohort of 240 gastric cancer patients. Bioinformatic analysis showed a significant correlation between DR5 and DNA replication, tumor mutation burden (TMB), and tumor stemness. Unlike death receptor 4 (DR4TRAIL-R1), DR5 was expressed in the cytoplasm and nucleus, and was found to be positively correlated with lymphovascular invasion, lymph node metastasis, and TNM stage. Patients with positive DR5 had worse overall survival (OS) (P = 0.006). The multivariate Cox model showed that DR5 is an independent poor prognostic factor (hazard ratio = 1.693). Furthermore, knockdown of DR5 inhibited aggressive behaviors, including proliferation and metastasis in gastric cancer cells, and inhibited lung metastasis in vivo. In summary, nuclear localization of DR5 expression is a poor prognosis factor in gastric cancer and promotes growth, invasion, and metastasis of tumor cells in vitro and in vivo.

Death Receptor 5 (TNFRSF10B) Is Upregulated and TRAIL Resistance Is Reversed in Hypoxia and Normoxia in Colorectal Cancer Cell Lines after Treatment with Skyrin, the Active Metabolite of Hypericum spp

Skyrin (SKR) is a plant bisanthraquinone secondary metabolite from the Hypericum genus with potential use in anticancer therapy. However, its effect and mechanism of action are still unknown. The negative effect of SKR on HCT 116 and HT-29 cancer cell lines in hypoxic and normoxic conditions was observed. HCT 116 cells were more responsive to SKR treatment as demonstrated by decreased metabolic activity, cellularity and accumulation of cells in the G1 phase. Moreover, an increasing number of apoptotic cells was observed after treatment with SKR. Based on the LC-MS comparative proteomic data from hypoxia and normoxia (data are available via ProteomeXchange with the identifier PXD019995), SKR significantly upregulated Death receptor 5 (DR5), which was confirmed by real-time qualitative PCR (RT-qPCR). Furthermore, multiple changes in the Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-activated cascade were observed. Moreover, the reversion of TRAIL resistance was observed in HCT 116, HT-29 and SW620 cell lines, even in hypoxia, which was linked to the upregulation of DR5. In conclusion, our results propose the use of SKR as a prospective anticancer drug, particularly as an adjuvant to TRAIL-targeting treatment to reverse TRAIL resistance in hypoxia.

Anti-Cancer Effect of Cordycepin on FGF9-Induced Testicular Tumorigenesis

Cordycepin, a bioactive constituent from the fungus Cordyceps sinensis, could inhibit cancer cell proliferation and promote cell death via induction of cell cycle arrest, apoptosis and autophagy. Our novel finding from microarray analysis of cordycepin-treated MA-10 mouse Leydig tumor cells is that cordycepin down-regulated the mRNA levels of FGF9, FGF18, FGFR2 and FGFR3 genes in MA-10 cells. Meanwhile, the IPA-MAP pathway prediction result showed that cordycepin inhibited MA-10 cell proliferation by suppressing FGFs/FGFRs pathways. The in vitro study further revealed that cordycepin decreased FGF9-induced MA-10 cell proliferation by inhibiting the expressions of p-ERK1/2, p-Rb and E2F1, and subsequently reducing the expressions of cyclins and CDKs. In addition, a mouse allograft model was performed by intratumoral injection of FGF9 and/or intraperitoneal injection of cordycepin to MA-10-tumor bearing C57BL/6J mice. Results showed that FGF9-induced tumor growth in cordycepin-treated mice was significantly smaller than that in a PBS-treated control group. Furthermore, cordycepin decreased FGF9-induced FGFR1-4 protein expressions in vitro and in vivo. In summary, cordycepin inhibited FGF9-induced testicular tumor growth by suppressing the ERK1/2, Rb/E2F1, cell cycle pathways, and the expressions of FGFR1-4 proteins, suggesting that cordycepin can be used as a novel anticancer drug for testicular cancers.

Apoptotic effect of fluoxetine through the endoplasmic reticulum stress pathway in the human gastric cancer cell line AGS

Gastric cancer is the fourth most common cancer in the world. Fluoxetine (FLX), a selective serotonin reuptake inhibitor, can inhibit the growth of cancer cells by inducing apoptotic cell death through various signaling pathways. This study was aimed to determine the mechanism of apoptotic cell death induced by FLX in AGS cells. MTT assay for cell viability test and colony forming assay was performed for detection of cell proliferation. Western blot analysis was conducted for protein expression. Increased fluorescence intensity and chromatin condensation were observed using DAPI staining. Production of reactive oxygen species (ROS) was measured by DCFDA assay. AGS cell proliferation was remarkedly inhibited by FLX in a dose-dependent manner starting at a concentration of 20 μM. The expression of death receptors was increased, which resulted in elevated expression of activated caspases and cleaved PARP, leading to FLX-induced apoptosis. Moreover, FLX significantly increased production of ROS, and N-acetyl cysteine, which scavenges ROS, attenuated the cytotoxic effects of FLX. In addition, treatment with FLX increased the expression of the endoplasmic reticulum (ER) stress marker, CHOP. P53 protein expression in AGS cells also decreased significantly with FLX treatment. Inhibition of ER stress significantly decreased the expressions of death receptor 5 (DR5), cleaved caspase 3, and cleaved PARP, but not to control levels. FLX-induced apoptosis in AGS involved upregulation of death receptors, ROS generation, and activation of ER stress.

A novel anti-DR5 antibody-drug conjugate possesses a high-potential therapeutic efficacy for leukemia and solid tumors

It is well known that tumor necrosis factor-related apoptosis inducing ligand receptor 1 or 2 (DR4/DR5) is specifically expressed in various tumor cells, but less or no expression in most normal cells. Many first generations of TRAIL agonists including recombinant preparations of TRAIL, agonistic antibodies against DR4/DR5 have been developed in phase I/II clinical trials for cancer therapy. However, the outcomes of clinical trials by using DR4/DR5 agonist mono-therapy were disappointed even though the safety profile was well tolerance. In the present study, we report an anti-DR5 antibody-drug conjugate (ADC, named as Zapadcine-1) possesses a higher potential for the therapy of lymphocyte leukemia and solid cancers. Methods: Zapadcine-1 was made by a fully humanized DR5-specific monoclonal antibody (Zaptuzumab) coupled via a cleavable linker to a highly toxic inhibitor of tubulin, monomethyl auristatin D (MMAD), by using ThioBridge technology. Cytotoxicity of the ADC in various tumor cells was identified by luminescent cell viability assay and the efficacy in vivo was determined in cells derived xenografts (CDX) of Jurkat E6-1, BALL-1, Reh, and patient derived xenografts (PDX) of human acute leukemia. Preliminary safety evaluation was carried out in rat and monkey. Results: Zapadcine-1 possesses a similar binding ability to the death receptor DR5 as the naked monoclonal antibody Zaptuzumab, and can be rapidly endocytosed into the lysosome of cancer cells. Zapadcine-1 specifically kills human lymphocyte leukemia cells and solid tumor cells, but not normal cells tested. More importantly, Zapadcine-1 drastically eliminates the xenografts in both CDX and PDX models of human acute leukemia. The excellent and comparable therapeutic efficacy is also observed in lung cancer NCI-H1975 CDX mouse model. The maximum-tolerated dose (MTD) of single injected Zapadcine-1 in rat and cynomolgus monkey shows an acceptable safety profile. Conclusion: These data demonstrate a promising anti-cancer activity, meriting further exploration of its potential as a novel cancer therapeutic agent, especially for the acute lymphocyte leukemia.

Activation of LXRβ inhibits proliferation, promotes apoptosis, and increases chemosensitivity of gastric cancer cells by upregulating the expression of ATF4

Recently, great advances have been achieved in both surgery and chemotherapy for the treatment of gastric cancer, but there is still poor prognosis for this disease. The aim of this study is to investigate the role of liver X receptor β (LXRβ) in chemosensitivity of gastric cancer SGC7901 cells. From 171 patients with gastric cancer, the gastric cancer and paracancerous tissues were selected to measure the expression of LXRβ and ATF4. Gastric cancer cell lines were cultured and screened to figure out the proliferation and apoptosis of gastric cancer SGC7901 cells with the treatment of LXRβ agonist (GW3965), ATF4 short hairpin RNA (shRNA), and chemotherapy drug paclitaxel. The expression of apoptosis-related gene cleaved caspase-3 was detected by Western blot analysis. First, we found that the expressions of LXRβ and ATF4 in gastric cancer tissues and cells were significantly lower than those in their paracancerous tissues and gastric mucosal epithelial cells. In addition, activation of LXRβ and paclitaxel treatment suppressed proliferation of SGC7901 cells, and the expression of ATF4 was upregulated in a concentration-dependent manner. Furthermore, shRNA significantly inhibited the expression of ATF4 and blocked the chemosensitivity of SGC7901 cells to LXRβ activation. Our study demonstrates that the expression of LXRβ was low in gastric cancer. In addition, activation of LXRβ may inhibit the proliferation of gastric cancer cells, promote apoptosis, and increase chemosensitivity by upregulating the expression of ATF4.

MSC-Delivered Soluble TRAIL and Paclitaxel as Novel Combinatory Treatment for Pancreatic Adenocarcinoma

Pancreatic cancer is the fourth leading cause of cancer death in western countries with more than 100,000 new cases per year in Europe and a mortality rate higher than 90%. In this scenario, advanced therapies based on gene therapies are emerging, thanks to a better understanding of tumour architecture and cancer cell alterations. We have demonstrated the efficacy of an innovative approach for pancreatic cancer based on mesenchymal stromal cells (MSC) genetically engineered to produce TNF-related Apoptosis Inducing Ligand (TRAIL). Here we investigated the combination of this MSC-based approach with the administration of a paclitaxel (PTX)-based chemotherapy to improve the potential of the treatment, also accounting for a possible resistance onset.

Methods: Starting from the BXPC3 cell line, we generated and profiled a TRAIL-resistant model of pancreatic cancer, testing the impact of the combined treatment in vitro with specific cytotoxicity and metabolic assays. We then challenged the rationale in a subcutaneous mouse model of pancreatic cancer, assessing its effect on tumour size accounting stromal and parenchymal organization.

Results: PTX was able to restore pancreatic cancer sensitivity to MSC-delivered TRAIL by reverting its pro-survival gene expression profile. The two compounds cooperate both in vitro and in vivo and the combined treatment resulted in an improved cytotoxicity on tumour cells.

Conclusion: In summary, this study uncovers the potential of a combinatory approach between MSC-delivered TRAIL and PTX, supporting the combination of cell-based products and conventional chemotherapeutics as a tool to improve the efficacy of the treatments, also addressing possible mechanisms of resistance.

Regulatory T-cell density and cytotoxic T lymphocyte density are associated with complete response to neoadjuvant paclitaxel and carboplatin chemoradiotherapy in gastric cancer

Regulatory T-cell density and cytotoxic T lymphocyte density are crucial in regulating antitumor immune responses. Tumor infiltration has marked therapeutic effects in gastric carcinoma, and there is evidence that chemoradiotherapy (CRT) exhibits an immune-mediated component. In the present study, the density of CD4⁺ and CD8⁺ cells were evaluated in post-CRT surgical samples from 68 patients with gastric cancer using immunohistochemistry. The associations between T-cell density, cytotoxic T lymphocyte density and clinical survival rate were also analyzed. Cytotoxic T lymphocyte density was associated with gastric carcinoma regression grade and regulatory T-cell density was also associated with gastric carcinoma regression grade. Of the patients who had a pathologic complete response, 84 and 76% were found to have a high CD3⁺ and CD4⁺ cell density, which was significantly different to patients who had a low CD3⁺ and CD4⁺ cell density. High cytotoxic T lymphocyte density was also associated with improved survival rates of patients with gastric cancer. In conclusion, these outcomes indicated that regulatory T-cell density and cytotoxic T lymphocyte density in the tumor microenvironment were associated with the response to neoadjuvant CRT and may represent a therapeutic target for gastric cancer.

Telomerase reverse transcriptase interference synergistically promotes tumor necrosis factor‑related apoptosis‑inducing ligand‑induced oral squamous cell carcinoma apoptosis and suppresses proliferation in vitro and in vivo

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is known to induce cell apoptosis in many types of cancer cells. However, some malignant cells still exhibit anti-apoptosis features induced by TRAIL; thus the underlying mechanisms that regulate sensitivity and resistance of tumor cells to TRAIL-induced apoptosis remain unclear. Human telomerase reverse transcriptase (hTERT) is overexpressed in most types of human tumors and is mostly inactive in somatic cells. The present study aimed to investigate the endogenous effects and mechanisms of hTERT inhibition and TRAIL overexpression on TRAIL-induced apoptosis of human oral squamous cell carcinoma (OSCC) cells. The effects of adeno-associated virus (AAV)-mediated TRAIL and hTERT gene silencing by RNA interference were investigated on the proliferation and apoptosis of human OSCC cells in vitro and in vivo. The present results suggest that knockdown of hTERT expression accelerated TRAIL-resistant OSCC cells to TRAIL-induced apoptosis and impaired OSCC cell proliferation. In addition, this process is accompanied by the upregulation of caspase-3, caspase-8 and caspase-9, and downregulation of B cell lymphoma-2. Additionally, the possible mechanisms underlying the association between TRAIL expression and hTERT silencing were explored. The results demonstrated that TRAIL expression levels were elevated when the hTERT gene was silenced, and notable anti-tumor effects were observed when TRAIL upregulation and hTERT gene silencing were carried out simultaneously. The present findings provide experimental evidence for the combined use of TRAIL and hTERT as a possible gene therapy strategy in oral cancer.

The mechanism study of lentiviral vector carrying methioninase enhances the sensitivity of drug-resistant gastric cancer cells to Cisplatin

Background

To investigate the mechanism of lentiviral vector carrying methioninase enhances the sensitivity of drug-resistant gastric cancer cells to Cisplatin.

Methods

Death receptors, anti-apoptotic protein, NF-κB, and TRAIL pathway-related factors were detected. The influence of LV-METase transfection on cell viability and pathway-related proteins were assessed by MTT method and western blot, respectively. Different treatments (NF-κB or caspase-3 inhibitor induction, TRAIL supplement, etc.) were performed in gastric cancer cells and the above parameters were analysed. Moreover, the connection between miR-21 and NF-κB or caspase-8 was determined by Chip and luciferase assay, respectively. LV-METase transfection drug-resistant gastric cancer cells were injected subcutaneously into mice.

Results

The expression of free MET, miR-21-5p, MDR1, P-gp, and DR5 was significantly increased in drug-resistant gastric cancer cell lines. When cells were transfected with LV-METase, intracellular TRAIL signalling was activated while NF-κB pathway was inhibited. Besides, enhanced TRAIL signalling or repressed NF-κB pathway can promote the sensitivity of drug-resistant strains to Cisplatin, and the combination shows more sensitive to sensitisation. LV-METase promoted TRAIL expression by reducing NF-κB, thereby contributing to the downregulation of P-gp and enhancing the susceptibility of drug-resistant gastric cancer cells to Cisplatin. Furthermore, miR-21 regulated by NF-κB mediated the expression of P-gp protein via inhibiting caspase-8, thus regulating Cisplatin-induced cell death.

Conclusions

Our results suggest that LV-METase has potential as a therapeutic agent for gastric cancer treatment.

Should We Keep Walking along the Trail for Pancreatic Cancer Treatment? Revisiting TNF-Related Apoptosis-Inducing Ligand for Anticancer Therapy

Despite recent advances in oncology, diagnosis, and therapy, treatment of pancreatic ductal adenocarcinoma (PDAC) is still exceedingly challenging. PDAC remains the fourth leading cause of cancer-related deaths worldwide. Poor prognosis is due to the aggressive growth behavior with early invasion and distant metastasis, chemoresistance, and a current lack of adequate screening methods for early detection. Consequently, novel therapeutic approaches are urgently needed. Many hopes for cancer treatment have been placed in the death ligand tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) since it was reported to induce apoptosis selectively in tumor cells in vitro and in vivo. TRAIL triggers apoptosis through binding of the trans-membrane death receptors TRAIL receptor 1 (TRAIL-R1) also death receptor 4 (DR4) and TRAIL receptor 2 (TRAIL-R2) also death receptor 5 (DR5) thereby inducing the formation of the death-inducing signaling complex (DISC) and activation of the apoptotic cascade. Unlike chemotherapeutics, TRAIL was shown to be able to induce apoptosis in a p53-independent manner, making TRAIL a promising anticancer approach for p53-mutated tumors. These cancer-selective traits of TRAIL led to the development of TRAIL-R agonists, categorized into either recombinant variants of TRAIL or agonistic antibodies against TRAIL-R1 or TRAIL-R2. However, clinical trials making use of these agonists in various tumor entities including pancreatic cancer were disappointing so far. This is thought to be caused by TRAIL resistance of numerous primary tumor cells, an insufficient agonistic activity of the drug candidates tested, and a lack of suitable biomarkers for patient stratification. Nevertheless, recently gained knowledge on the biology of the TRAIL-TRAIL-R system might now provide the chance to overcome intrinsic or acquired resistance against TRAIL and TRAIL-R agonists. In this review, we summarize the status quo of clinical studies involving TRAIL-R agonists for the treatment of pancreatic cancer and critically discuss the suitability of utilizing the TRAIL-TRAIL-R system for successful treatment.

ShDcR3 sensitizes TRAIL-resistant HCC cells by inducing caspase-dependent apoptosis while suppressing NF-κB dependent cFLIPL expression

Evidence has shown that most hepatocellular carcinoma (HCC) cells are resistant to tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. However, the molecular mechanisms underlying TRAIL-mediated apoptosis resistance are not well understood. In this study, we reported that downregulation of Decoy receptor 3 (DcR3) expression by lentiviral vectors carrying shRNA against DcR3 (LV-ShDcR3, shDcR3) in Huh7 both greatly enhanced TRAIL-mediated apoptosis and reduced cell proliferation capability. In addition, silencing DcR3 resulted in upregulation of the cell apoptotic regulators including Bid, caspase-3, and caspase-8. Caspase inhibitors inhibited shDcR3-mediated cell death, which indicated that downregulation of DcR3 expression in Huh7 cells increased TRAIL-induced caspase-dependent apoptotic cell death. Furthermore, although the knockdown of DcR3 altered the expression of some Bcl-2- and IAP-family proteins, this change was inhibited by pretreatment with a pancaspase inhibitor, which indicated the cytotoxic effect of shDcR3 was not due to the expression of these proteins. In contrast, shDcR3 significantly inhibited TRAIL-induced transcription factor nuclear κB (NF-κB) activation through the IκB kinase (IKK) pathway, as well as inhibited TRAIL-induced increases in FLICE-inhibitory protein long form (cFLIP_L) expression at the transcriptional level. Silencing cFLIP_L expression mimicked the cytotoxic effect of shDcR3 on TRAIL-mediated cell apoptosis. Moreover, overexpression of cFLIP_L effectively prevented the increase in cell apoptosis in Huh7 cells co-treated with TRAIL and shDcR3. Taken together, our findings indicated that silencing DcR3 sensitizes TRAIL-mediated apoptosis in HCC cells by inhibiting NF-κB.

SPARCL1 suppresses cell migration and invasion in renal cell carcinoma

Previous studies have shown that the human SPARC‑like 1 (SPARCL1) is crucial for human cancer migration and invasion. In the present study, the expression, biological function and possible molecular regulatory mechanisms of SPARCL1 were investigated in human renal cell carcinoma (RCC). The protein expression of SPARCL1 in cells was evaluated using western blot analysis and immunohistochemical staining in the tissue microarray. The effects of SPARCL1 on the biological behaviors of RCC cells were assessed using in vitro assays. The present study also provisionally investigated the role of SPARCL1 on the mitogen‑activated protein kinase (MAPK) signaling pathway. The results revealed that the expression of SPARCL1 was decreased in the RCC cell lines examined and in the tissue microarray. The overexpression of SPARCL1 significantly inhibited cell migration and invasion, and this may have been due to the inactivation of p38/c‑Jun N‑terminal kinase (JNK)/extracellular signal‑regulated kinase (ERK) MAPKs. The results showed that high expression levels of SPARCL1 offered potential as a useful prognostic factor in RCC. Taken together, the present study demonstrated that the expression of SPARCL1 was downregulated in RCC cells and tissues, however, the overexpression of SPARCL1 inhibited RCC cell migration and invasion. SPARCL1 also reduced the expression of phosphorylated p38/JNK/ERK MAPKs. These data suggested that increasing the protein expression level of SPARCL1 may be novel strategy for treating RCC.

Targeting Apoptotic Activity Against Prostate Cancer Stem Cells

Numerous data suggest that an increase of cancer stem cells (CSCs) in tumor mass can be the reason for failure of conventional therapies because of their resistance. CD44+/CD24- cells are a putative cancer stem cells subpopulation in prostate cancer. TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) is an activator of apoptosis in tumor cells. However, some tumors are TRAIL-resistant. Cancer cells can be re-sensitized to TRAIL induced apoptosis by a combination of TRAIL and taxanes. The aim of this work was to analyze the enhancement of the anticancer effect of TRAIL by paclitaxel, cabazitaxel and docetaxel in the whole population of PC3 and DU145 prostate cancer cells, but also in CD44+/CD24- prostate cancer stem cells. We examined the apoptotic effect of TRAIL and taxanes using flow cytometry and Annexin-V-PE staining. The co-treatment with taxanes and TRAIL enhanced significantly the apoptosis in CD44+/CD24- cells only in PC3 cell line but not in DU145 cells. We discovered also that taxanes can increase the expression of death receptor TRAIL-R2 in PC3 prostate cancer cells. The results of our study show that treatment with paclitaxel, cabazitaxel and docetaxel is able to enhance the apoptosis induced by TRAIL even in prostate cancer stem cells.

Paclitaxel-loaded pluronic F127/P123 silica nanocapsules with surface conjugated rhTRAIL for targeted cancer therapy

A novel anticancer drug PFPSNT, paclitaxel (PTX)-loaded polymeric F127/P123 silica nanocapsules conjugated with TRAIL (tumor necrosis factor (TNF)-related apoptosis-inducing ligand), was designed and synthesized.