Tandem therapy for retinoblastoma: immunotherapy and chemotherapy enhance cytotoxicity on retinoblastoma by increasing apoptosis

Ribonucleotide reductase subunit M2 promotes proliferation and epithelial-mesenchymal transition via the JAK2/STAT3 signaling pathway in retinoblastoma

Retinoblastoma (RB) is an intraocular malignant tumor that often occurs in children. Along with the improvement of treatment strategies, the cure rate of RB has increased significantly. However, the treatment of advanced and recurrent RB remains as a critical challenge. Therefore, studying the molecular mechanisms underlying the progression of RB is essential for the development of novel and effective therapeutic strategies. Through the analysis of a previously published microarray study, we found that ribonucleotide reductase subunit M2 (RRM2) was highly expressed in RB tissues as compared to normal tissues. The purpose of this study is to clarify the role and mechanism of RRM2 in regulating the progression of RB. We first demonstrated that RRM2 expression level in RB tissues and cell lines was significantly higher when compared to that in normal retinal tissue and cell lines, and high RRM2 expression level was associated with a poorer overall survival of patients. In RB cells, RRM2 overexpression promoted cell proliferation, migration, invasion and epithelial-mesenchymal transformation (EMT), while RRM2 silencing suppressed these biological features. Silencing RRM2 reduced the activation of Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway, and the presence of JAK2/STAT3 signaling pathway inhibitor INCB attenuated the effect of RRM2 overexpression. Collectively, our data indicate that RRM2 promotes the progression of RB by activating JAK2/STAT3 signaling pathway. Targeting RRM2/JAK2/STAT3 axis lays a theoretical foundation for the formulation of novel RB therapy.

Circ_0075804 promotes the malignant behaviors of retinoblastoma cells by binding to miR-138-5p to induce PEG10 expression

BACKGROUND

It has been gradually recognized that circular RNAs (circRNAs) are important modulators in multiple malignancies. Here, we analyzed the function of circ_0075804 and explored its associated mechanism in regulating retinoblastoma (RB) progression.

METHODS

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blot assay were utilized to measure RNA and protein expression, respectively. Cell proliferation was analyzed by Cell counting kit-8 (CCK8) assay and 5-Ethynyl-2'-deoxyuridine (EdU) assay. Cell apoptosis was assessed by flow cytometry. Cell migration and invasion abilities were analyzed by wound healing assay and transwell invasion assay. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were applied to verify intermolecular target relations. Xenograft tumor model was used to analyze the role of circ_0075804 in tumor growth in vivo.

RESULTS

Circ_0075804 expression was markedly up-regulated in RB tissues and cell lines. Circ_0075804 knockdown restrained the proliferation, migration and invasion whereas promoted the apoptosis of RB cells. Circ_0075804 acted as a molecular sponge for microRNA-138-5p (miR-138-5p), and circ_0075804 silencing-induced effects were partly reversed by miR-138-5p knockdown in RB cells. MiR-138-5p interacted with the 3' untranslated region (3'UTR) of paternally expressed 10 (PEG10). Circ_0075804 positively regulated PEG10 level by sponging miR-138-5p in RB cells. PEG10 overexpression largely overturned miR-138-5p overexpression-mediated effects in RB cells. Circ_0075804 knockdown blocked xenograft tumor growth in vivo.

CONCLUSION

Circ_0075804 promoted RB progression via miR-138-5p-dependent regulation of PEG10, which provided new insight in RB therapy.

GD2-specific chimeric antigen receptor-modified T cells targeting retinoblastoma - assessing tumor and T cell interaction

A novel disialoganglioside 2 (GD2)-specific chimeric antigen receptor (CAR)-modified T cell therapy against retinoblastoma (RB) were generated. GD2-CAR consists of a single-chain variable fragment (scFv) derived from a monoclonal antibody, hu3F8, that is linked with the cytoplasmic signaling domains of CD28, 41BB, a CD3ζ, and an inducible caspase 9 death fusion partner. GD2 antigen is highly expressed in Y79RB cell line and in several surgical RB tumor specimens. In vitro co-culture experiments revealed the effective killing of Y79RB cells by GD2-CAR T cells, but not by control CD19-CAR T cells. The killing activities of GD2-CAR T cells were diminished when repeatedly exposed to the tumor, due to an attenuated expression of GD2 antigen on tumor cells and upregulation of inhibitory molecules of the PD1 and PD-L1 axis in the CAR T cells and RB tumor cells respectively. This is the first report to describe the potential of GD2-CAR T cells as a promising therapeutic strategy for RB with the indication of potential benefit of combination therapy with immune checkpoint inhibitors.

RPL41 sensitizes retinoblastoma cells to chemotherapeutic drugs via ATF4 degradation

Retinoblastoma is the most common intraocular cancer with metastatic potential affecting infants and children. Although chemotherapy is available for retinoblastoma, side effects and drug resistance are frequent. Rpl41, encoding ribosomal protein L41 (RPL41), has been identified as a tumor suppressor gene, and its targeted degradation of activating transcription factor 4 (ATF4) produces an antitumor effect. The goal of the present study is to provide experimental evidence for the clinical application of a small peptide regimen in combination with chemotherapy for the treatment of retinoblastoma and to investigate the mechanism of their combined cytotoxicity. It was observed that treatment with the RPL41 peptide alone decreased the viability, migration, and invasion of retinoblastoma Y79 and Weri-Rb1 cells, in addition to promoting cell apoptosis and cell cycle arrest. Furthermore, RPL41 protein levels showed a significantly decreased trend in retinoblastoma specimens, whereas ATF4 protein levels tended to be increased. Mechanistically, ATF4 degradation as a result of RPL41 peptide treatment was observed in retinoblastoma Y79 and Weri-Rb1 cells. Most important, low-dose administration of the RPL41 peptide significantly enhanced the antitumor effect of carboplatin, and further analysis confirmed their synergistic effect as anti-retinoblastoma therapy, indicating that RPL41 sensitized Y79 and Weri-Rb1 retinoblastoma cells to carboplatin. Thus, our data provide a preclinical rationale for the exploration of the RPL41 peptide as a potential adjuvant to carboplatin treatment in retinoblastoma.

Dinutuximab Synergistically Enhances the Cytotoxicity of Natural Killer Cells to Retinoblastoma Through the Perforin-Granzyme B Pathway

Purpose

Conventional chemotherapy and enucleation usually fail to cure advanced retinoblastoma. We investigated the retinoblastoma immune microenvironment and the efficacy of the combination of dinutuximab and CD16-expressing NK-92MI (NK-92MI^hCD16-GFP) cells on retinoblastoma cells in this study.

Patients and Methods

Immunohistochemistry and flow cytometry (FC) were performed to assess the expression level of GD2 in retinoblastoma tissues and cells. Gene set enrichment analysis (GSEA), immunohistochemisrztry and immunocytochemistry were conducted to assess the retinoblastoma immune microenvironment and the integrity of the blood-retinal barrier (BRB). After overexpressing CD16 in NK-92MI cells, fluorescence-activated cell sorting (FACS) was applied to select the positive subpopulation. LDH assays and FC were used to detect LDH release and apoptosis in retinoblastoma cells subjected to a combination of dinutuximab and NK-92MI^hCD16-GFP cells. Finally, the release of perforin-granzyme B and the expression of CD107a in NK-92MI^hCD16-GFP stimulated by retinoblastoma cells were assessed via enzyme-linked immunosorbent assays (ELISAs) and FC in the presence of dinutuximab or an isotype control.

Results

GD2 was heterogeneously expressed in retinoblastoma tissues and cell lines and positively correlated with proliferation and staging. GSEA revealed the immunosuppressive status of retinoblastoma microenvironment. The immune cell profile of retinoblastoma tissues and vitreous bodies suggested BRB destruction. LDH release and apoptosis in retinoblastoma cells caused by NK-92MI^hCD16-GFP cells were significantly enhanced by dinutuximab. Finally, the release of perforin-granzyme B and the expression of CD107a in NK-92MI^hCD16-GFP cells stimulated by retinoblastoma cells were obviously increased by dinutuximab.

Conclusion

This study indicates that retinoblastoma impairs the integrity of the BRB and contributes to dysregulated immune cell infiltrates. GD2 is a specific target for natural killer (NK) cell-based immunotherapy and that the combination of dinutuximab and NK-92MI^hCD16-GFP cells exerts potent antitumor effects through antibody-dependent cell-mediated cytotoxicity.

MicroRNA-361-3p regulates retinoblastoma cell proliferation and stemness by targeting hedgehog signaling

Retinoblastoma (RB) is the most common type of intraocular malignancy in children. During RB oncogenesis, sonic hedgehog (SHH) is commonly differentially expressed. Additionally, microRNAs (miRs) are known to serve crucial roles as oncogenes or tumor suppressors. Specifically, miR-361-3p has been revealed to serve a vital role in cutaneous squamous cell carcinoma, cervical cancer, prostate cancer, colorectal cancer, gastric cancer, hepatocellular carcinoma, breast cancer and lung cancer. However, the role of miR-361-3p in RB and the potential molecular mechanisms involved remain unknown. Therefore, the current study aimed to determine the involvement of miR-361-3p in the development of RB by targeting SHH signaling. In the present study, miR-361-3p expression levels in RB tissue and serum samples obtained from 10 patients with RB, normal retinal tissue and serum samples obtained from 10 healthy controls, and two human RB cell lines (Y79 and Weri-Rb-1) were determined using reverse transcription-quantitative polymerase chain reaction. In addition, a cell counting kit-8 assay, a cell transfection assay, a MTT assay, western blotting, a tumor sphere formation assay and a luciferase assay were used to assess the expression, function and molecular mechanism of miR-361-3p in human RB. It was demonstrated that miR-361-3p was significantly downregulated in RB tissues, RB serum and RB cell lines compared with normal retinal tissues and normal serum. The ectopic expression of miR-361-3p decreased RB cell proliferation and stemness. Furthermore, GLI1 and GLI3 were verified as potential direct targets of miR-361-3p. miR-361-3p was also revealed to exhibit a negative correlation with GLI1/3 expression in RB samples. Taken together, the results indicate that miR-361-3p functions as a tumor suppressor in the carcinogenesis and progression of RB by targeting SHH signaling. Thus, miR-361-3p should be further assessed as a potential therapeutic target for RB treatment.

SYK-targeted dendritic cell-mediated cytotoxic T lymphocytes enhance the effect of immunotherapy on retinoblastoma

PURPOSE

Retinoblastoma (RB) is the most common primary intraocular tumor in children. Chemotherapy is currently the main method of RB treatment. Unfortunately, RB often becomes chemoresistant and turns lethal. Here, we used in vitro cell immunotherapy to explore whether adoptive immunotherapy could be used as a potential treatment for RB. We focused on spleen tyrosine kinase (SYK), which is significantly upregulated in RB cells and serves as a marker for RB cells.

METHODS

Using lentiviruses, we genetically modified dendritic cells (DCs) to express and present the SYK peptide antigen to cytotoxic T lymphocytes (CTLs) in vitro. We used SYK-negative cell lines (MDA-MB-231, MCF-10A, and hTERT-RPE1) and SYK-positive cell lines (MCF-7 and RB-Y79) to evaluate the specificity and cytotoxicity of DC presented CTLs using FACS, live-cell imaging, and RNA interference.

RESULTS

The cytotoxicity of CTLs induced by SYK-overexpressing DCs (SYK-DC-CTLs) was enhanced more than three times in SYK-positive cell lines compared with SYK-negative cell lines. DCs primed with SYK could drive CTL cytotoxicity against SYK-positive cell lines but not against SYK-negative cell lines. Moreover, SYK-silenced RB-Y79 cells successfully evaded the cytotoxic attack from SYK-DC-CTLs. However, SYK-DC-CTLs could target SYK overexpressed hTERT-RPE1 cells, suggesting that SYK is a specific antigen for RB. Furthermore, SYK-DC-CTL exhibited specific cytotoxicity against carboplatin-resistant RB-Y79 cells in vitro.

CONCLUSIONS

Our data showed that SYK could be a potential immunotherapy target mediated by DCs. We propose SYK as a candidate target for treatment of chemoresistant RB.

Blockade of sonic hedgehog signaling decreases viability and induces apoptosis in retinoblastoma cells: The key role of the PI3K/Akt pathway

Retinoblastoma (RB) is the most common type of malignant intraocular cancer in teenagers. One of the proteins abnormally expressed during oncogenesis of RB is sonic hedgehog (SHH), which possesses the capability to selectively activate transcription factors of different genes. However, the detailed function of SHH in RB remains unknown. Thus, the present study sought to investigate the role of SHH in the development of RB. The human RB WERI-Rb-1 cell line was used as an in vitro model for the knockdown of SHH by a specific short hairpin RNA (shRNA). To assess the effect of SHH inhibition on cell growth and apoptosis, cell viability, colony formation and flow cytometry assays were conducted. WERI-Rb-1 cells transfected with an shRNA targeting SHH were treated with the phosphoinositide-3 kinase (PI3K)/Akt agonist insulin-like growth factor 1 (IGF-1) to investigate the possible mechanism by which SHH promotes RB. The present results revealed that the silencing of SHH induced G1 cell-cycle arrest and apoptosis in WERI-Rb-1 cells and led to a decrease in cell viability, indicating that SHH has a critical role in the determination of RB cell survival. Moreover, according to the results of the IGF-1 assays, suppression of PI3K/Akt was a prerequisite for SHH inhibition, illuminating its potential role in the treatment of RB. The findings outlined in the present study elucidate a clear link between SHH and the PI3K/Akt pathway in RB cell survival, which could provide valuable inspiration for the advancement of therapies against RB.

Quercetin inhibits angiogenesis-mediated human retinoblastoma growth by targeting vascular endothelial growth factor receptor

Retinoblastoma (RB) is the most common malignant intraocular cancer in teenagers, occurrence of which depends on the mutation of multiple genes. Among all the signaling pathways involved in the oncogenesis of RB, the process of angiogenesis has been demonstrated to be associated with the local invasive growth and metastasis of this cancer type. Quercetin (Que) is a typical flavonoid and has been reported to inhibit angiogenesis in various types of tumors. In the present study, the effect of Que on RB cells and angiogenesis of RB was evaluated. The human RB Y79 cell line was subjected to treatment with Que of various concentrations. Viability, invasion and migration ability and apoptosis of Y79 cells were subsequently measured to assess the effect of Que on RB cells. In addition, the expression of vascular endothelial growth factor receptor (VEGFR) was also quantified. It was revealed that Que inhibited RB cell growth and invasion in vitro in a dose-dependent manner, with 100 µM Que exhibiting the strongest inhibitory effect. In addition, Que downregulated the expression of VEGFR, which was an indicator of the blockade of angiogenesis in RB by targeting VEGF. The effect of Que on angiogenesis was also observed to be dose-dependent. The results of the present study indicated that Que may be a potential anti-RB therapy due to its anti-angiogenesis effect.

Overexpression of KAI1 inhibits retinoblastoma metastasis in vitro

The present study aimed to investigate the expression of cluster of differentiation 82 (KAI1), a gene involved in the suppression of tumor metastasis, in human retinoblastoma (RB) tissue and to study the effect of KAI1 expression on RB cell migration and invasion. KAI1 expression was examined in 26 patients with non-invasive and invasive retinoblastoma using reverse transcription-quantitative polymerase chain reaction and western blot analysis. A lentiviral vector containing KAI1 cDNA was used to transfect the two RB cell lines, HXO-Rb44-Gl and Y79. Following successful transfection, the migratory and invasive capacity of the two RB cell lines was evaluated using a Transwell^® migration assay. KAI1 expression was observed to be downregulated in invasive RB compared to non-invasive RB. The migratory and invasive capacities of KAI1 transfected cell lines were significantly decreased compared to those of the control cells. KAI1 may be involved in retinoblastoma metastasis, and increased expression of KAI1 significantly inhibits the metastatic ability of RB cells in vitro.

Immunotherapy of DC-CIK cells enhances the efficacy of chemotherapy for solid cancer: a meta-analysis of randomized controlled trials in Chinese patients

OBJECTIVE

Professional antigen-presenting dendritic cells (DCs) and cytokine-induced killer (CIK) cells, components of anti-cancer therapy, have shown clinical benefits and potential to overcome chemotherapeutic resistance. To evaluate whether DC-CIK cell-based therapy improves the clinical efficacy of chemotherapy, we reviewed the literature on DC-CIK cells and meta-analyzed randomized controlled trials (RCTs).

METHODS

We searched several databases and selected studies using predefined criteria. RCTs that applied chemotherapy with and without DC-CIK cells separately in two groups were included. Odds ratio (OR) and mean difference (MD) were reported to measure the pooled effect.

RESULTS

Twelve reported RCTs (826 patients), which were all performed on Chinese patients, were included. Combination therapy exhibited better data than chemotherapy: 1-year overall survival (OS) (OR=0.22, P<0.01), 2-year OS (OR=0.28, P<0.01), 3-year OS (OR=0.41, P<0.01), 1-year disease-free survival (DFS) (OR=0.16, P<0.05), 3-year DFS (OR=0.32, P<0.01), objective response rate (ORR) (OR=0.54, P<0.01), and disease control rate (DCR) (OR=0.46, P<0.01). Moreover, the levels of CD3(+) T-lymphocytes (MD=-11.65, P<0.05) and CD4(+) T-lymphocytes (MD=-8.18, P<0.01) of the combination group were higher.

CONCLUSIONS

Immunotherapy of DC-CIK cells may enhance the efficacy of chemotherapy on solid cancer and induces no specific side effect. Further RCTs with no publishing bias should be designed to confirm the immunotherapeutic effects of DC-CIK cells.

Phenotypic characterization and anti-tumor effects of cytokine-induced killer cells derived from cord blood

BACKGROUND AIMS

Cytokine-induced killer (CIK) cell therapy represents a feasible immunotherapeutic option for treating malignancies. However, the number of anti-tumor lymphocytes cannot be easily obtained from the cancer patients with poor immunity status, and older patients cannot tolerate repeated collection of blood. Cord blood-derived CIK (CB-CIK) cells have shown efficacy in treating the patients with cancer in several clinical trials. This study was conducted to evaluate the biological characteristics and anti-tumor function of CB-CIK cells.

METHODS

The immunogenicity, chemokine receptors and proliferation of CB-CIK cells were analyzed by flow cytometry. The CIK cells on day 13 were treated with cisplatin and the anti-apoptosis capacity was analyzed. The function of CB-CIK cells against the human cancer was evaluated both in vitro and in vivo.

RESULTS

Compared with peripheral blood-derived CIK (PB-CIK) cells, CB-CIK cells demonstrated lower immunogenicity and increased proliferation rates. CB-CIK cells also had a higher percentage of main functional fraction CD3(+)CD56(+). The anti-apoptosis ability of CB-CIK cells after treatment with cisplatin was higher than that of PB-CIK cells. Furthermore, CB-CIK cells were effective for secreting interleukin-2 and interferon-γ and a higher percentage of chemokine receptors CCR6 and CCR7. In addition, tumor growth was greatly inhibited by CB-CIK treatment in a nude mouse xenograft model.

CONCLUSIONS

CB-CIK cells exhibit more efficient anti-tumor activity in in vitro analysis and in the preclinical model and may serve as a potential therapeutic approach for the treatment of cancer.

An update on new adoptive immunotherapy strategies for solid tumors with cytokine-induced killer cells

INTRODUCTION

Cytokine-induced killer (CIK) cells are mainly CD3(+)CD56(+) NKT cells exhibiting non-MHC-restricted cytotoxicity against a broad range of tumors. Much research is going on to improve CIK cell effectivity and to evaluate the clinical benefit of different combinations with conventional therapies.

AREAS COVERED

This review provides an update on in vitro/in vivo studies and clinical trials applying CIK cells for the treatment of solid tumors. This comprises attempts using additional cytokines, genetic engineering and combinations with different conventional and modern therapies.

EXPERT OPINION

Since our last review, much effort has been made to improve CIK cell cytotoxicity and clinical effectivity. Targeted CIK cell therapy and combinations of CIK cells with antiangiogenic drugs or oncolytic viruses are examples of recent outstanding achievements in the field of adoptive CIK cell therapy. The clinical application of CIK cells in combination with conventional therapies, especially, obtained promising results. However, the best combination and the optimal therapy schedule have yet to be defined.

Tumour cell lysate-loaded dendritic cell vaccine induces biochemical and memory immune response in castration-resistant prostate cancer patients

Background:

Recently, we produced a tumour antigen-presenting cells (TAPCells) vaccine using a melanoma cell lysate, called TRIMEL, as an antigen source and an activation factor. Tumour antigen-presenting cells induced immunological responses and increased melanoma patient survival. Herein, we investigated the effect of TAPCells loaded with prostate cancer cell lysates (PCCL) as an antigen source, and TRIMEL as a dendritic cell (DC) activation factor; which were co-injected with the Concholepas concholepas haemocyanin (CCH) as an adjuvant on castration-resistant prostate cancer (CRPC) patients.

Methods:

The lysate mix capacity, for inducing T-cell activation, was analysed by flow cytometry and Elispot. Delayed-type hypersensitivity (DTH) reaction against PCCL, frequency of CD8⁺ memory T cells (Tm) in blood and prostate-specific antigen (PSA) levels in serum were measured in treated patients.

Results:

The lysate mix induced functional mature DCs that were capable of activating PCCL-specific T cells. No relevant adverse reactions were observed. Six out of 14 patients showed a significant decrease in levels of PSA. DTH⁺ patients showed a prolonged PSA doubling-time after treatment. Expansion of functional central and effector CD8⁺ Tm were detected.

Conclusion:

Treatment of CRPC patients with lysate-loaded TAPCells and CCH as an adjuvant is safe: generating biochemical and memory immune responses. However, the limited number of cases requires confirmation in a phase II clinical trial.