TLR3 agonist and Sorafenib combinatorial therapy promotes immune activation and controls hepatocellular carcinoma progression

Therapeutic liposomal combination to enhance chemotherapy response and immune activation of tumor microenvironment

Multiple oxaliplatin-resistance mechanisms have been proposed such as increase of anti-inflammatory M2 macrophages and lack of cytotoxic T-cells. Thereby oxaliplatin chemotherapy promotes an immunosuppressive tumor microenvironment and inhibits anti-tumor efficacy. It has been shown that toll-like receptor (TLR) agonists are capable of triggering broad inflammatory responses, which may potentially reduce oxaliplatin-resistance and improve the efficacy of chemotherapy. In this study, we established colorectal tumor-bearing zebrafish and mice, and investigated the effects of TLR agonists and oxaliplatin in macrophage function and anti-tumor T cell immunity as well as tumor growth control in vivo. To increase the potential of this strategy as well minimize side effects, neutral liposomes carrying oxaliplatin and cationic liposomes co-loaded with TLR agonists Poly I:C and R848 were employed for maximum immune activation. Both of two liposomal systems exhibited good physicochemical properties and excellent biological activities in vitro. The combination strategy delivered by liposomes showed more pronounced tumor regression and correlated with decreased M2 macrophage numbers in both zebrafish and mice. Increasing numbers of dendritic cells, DC maturation and T cell infiltration mediated via immunogenic cell death were observed in treated mice. Our study offers valuable insights into the potential of liposomal combination therapy to improve cancer treatment by reprogramming the tumor microenvironment and enhancing immune responses.

Liposomes-Encapsulating Double-Stranded Nucleic Acid (Poly I:C) for Head and Neck Cancer Treatment

Polyriboinosinic acid-polyribocytidylic acid (Poly I:C) serves as a synthetic mimic of viral double-stranded dsRNA, capable of inducing apoptosis in numerous cancer cells. Despite its potential, therapeutic benefits, the application of Poly I:C has been hindered by concerns regarding toxicity, stability, enzymatic degradation, and undue immune stimulation, leading to autoimmune disorders. To address these challenges, encapsulation of antitumor drugs within delivery systems such as cationic liposomes is often employed to enhance their efficacy while minimizing dosages. In this study, we investigated the potential of cationic liposomes to deliver Poly I:C into the Head and Neck 12 (HN12) cell line to induce apoptosis in the carcinoma cells and tumor model. Cationic liposomes made by the hydrodynamic focusing method surpass traditional methods by offering a continuous flow-based approach for encapsulating genes, which is ideal for efficient tumor delivery. DOTAP liposomes efficiently bind Poly I:C, confirmed by transmission electron microscopy images displaying their spherical morphology. Liposomes are easily endocytosed in HN12 cells, suggesting their potential for therapeutic gene and drug delivery in head and neck squamous carcinoma cells. Activation of apoptotic pathways involving MDA5, RIG-I, and TLR3 is evidenced by upregulated caspase-3, caspase-8, and IRF3 genes upon endocytosis of Poly(I:C)-encapsulated liposomes. Therapeutic evaluations revealed significant inhibition of tumor growth with Poly I:C liposomes, indicating the possibility of MDA5, RIG-I, and TLR3-induced apoptosis pathways via Poly I:C liposomes in HN12 xenografts in J:NU mouse models. Comparative histological analysis underscores enhanced cell death with Poly I:C liposomes, warranting further investigation into the precise mechanisms of apoptosis and inflammatory cytokine response in murine models for future research.

Post-translational modifications and immune responses in liver cancer

Post-translational modification (PTM) refers to the covalent attachment of functional groups to protein substrates, resulting in structural and functional changes. PTMs not only regulate the development and progression of liver cancer, but also play a crucial role in the immune response against cancer. Cancer immunity encompasses the combined efforts of innate and adaptive immune surveillance against tumor antigens, tumor cells, and tumorigenic microenvironments. Increasing evidence suggests that immunotherapies, which harness the immune system's potential to combat cancer, can effectively improve cancer patient prognosis and prolong the survival. This review presents a comprehensive summary of the current understanding of key PTMs such as phosphorylation, ubiquitination, SUMOylation, and glycosylation in the context of immune cancer surveillance against liver cancer. Additionally, it highlights potential targets associated with these modifications to enhance the response to immunotherapies in the treatment of liver cancer.

In situ vaccination followed by intramuscular poly-ICLC injections for the treatment of hepatocellular carcinoma in mouse models

The efficacy of treatment for advanced hepatocellular carcinoma (HCC) has remained limited. Polyinosinic-polycytidylic acid-poly-L-lysine carboxymethylcellulose (poly-ICLC) is a synthetic double-stranded RNA that serves as a viral mimic and induces an immune response. Intratumoral (IT) poly-ICLC injections can induce an autovaccination effect and prime the immune system, whereas intramuscular (IM) injection of poly-ICLC can attract and maintain tumor-specific cytotoxic T lymphocytes in tumors. We found that IT injection of poly-ICLC upregulated the expression of CD83 and CD86 on conventional type 1 dendritic cells in tumors. Combination therapy with IT followed by IM injections of poly-ICLC significantly inhibited tumor growth and increased the tumor-infiltrating CD8⁺ T cells in two syngeneic mouse models of HCC. Depletion of CD8⁺ T cells attenuated the antitumor effect. An IFN-γ enzyme-linked immunospot of purified tumoral CD8⁺ T cells revealed a significant proportion of tumor-specific T cells. Finally, the sequential poly-ICLC therapy induced abscopal effects in two dual-tumor models. This study provides evidence that the sequential poly-ICLC therapy significantly increased infiltration of tumor-specific CD8⁺ T cells in the tumors and induced CD8⁺ T cell-dependent inhibition of tumor growth, as well as abscopal effects.

In vitro characterization of immune modulating drug-eluting immunobeads towards transarterial embolization in cancer

Hepatocellular carcinoma (HCC) is an aggressive liver cancer with limited effective treatment options. In this study, we selected TLR agonists imiquimod (IMQ), gardiquimod (GARD), GS-9620 and DSR 6434, and a small molecule checkpoint inhibitor, BMS-202, for characterization of drug loading and release from radiopaque embolic beads (DC Bead LUMI) for potential use in image-guided transarterial embolization (TACE) of HCC. The maximum drug loading capacity and amount of drug released over time were determined by high performance liquid chromatography and compared with the commonly used anthracycline, doxorubicin hydrochloride (Dox). Maximum drug loading was 204.54 ± 3.87, 65.28 ± 3.09, 65.95 ± 6.96, 65.97 ± 1.54, and 148.05 ± 2.24 mg of drug per milliliter of DC Bead LUMI for Dox, GARD, DSR 6434, IMQ, and BMS-202, respectively. Fast loading and subsequent rapid release in saline were observed for IMQ, GARD, and DSR 6434. These drugs could also be partially removed from the beads by repeated washing with de-ionized water suggesting weak interaction with the beads. Aggregation of IMQ was observed in water and saline. GS-9620 partially decomposed in the solubilizing solution, so loading and release were not characterized. Compared to TLR agonists, slower loading and release were observed for Dox and BMS-202. Potential factors influencing drug loading into and release from DC Bead LUMI including steric hinderance, hydrophobicity, drug pKa, and the electrostatic nature of the beads are discussed. The maximum loading capacity of BMS-202 and Dox in DC Bead LUMI exceeded the maximum theoretical loading capacity of the beads expected from ionic interaction alone suggesting additional drug-bead or drug-drug interactions may play a role. Slightly more release was observed for BMS-202 at early time points followed by a slower release compared to Dox. Further study of these drug-bead combinations is warranted in search of new tools for locoregional delivery of immune-modulating agents for treatment of HCC via drug-eluting bead chemoembolization.

ADAR3 activates NF-κB signaling and promotes glioblastoma cell resistance to temozolomide

The RNA binding protein ADAR3 is expressed exclusively in the brain and reported to have elevated expression in tumors of patients suffering from glioblastoma compared to adjacent brain tissue. Yet, other studies have indicated that glioblastoma tumors exhibit hemizygous deletions of the genomic region encompassing ADAR3 (10p15.3). As the molecular and cellular consequences of altered ADAR3 expression are largely unknown, here we directly examined the impacts of elevated ADAR3 in a glioblastoma cell line model. Transcriptome-wide sequencing revealed 641 differentially expressed genes between control and ADAR3-expressing U87-MG glioblastoma cells. A vast majority of these genes belong to pathways involved in glioblastoma progression and are regulated by NF-κB signaling. Biochemical and molecular analysis indicated that ADAR3-expressing U87-MG cells exhibit increased NF-κB activation, and treatment with an NF-κB inhibitor abrogated the impacts of ADAR3 on gene expression. Similarly, we found that increased cell survival of ADAR3-expressing cells to temozolomide, the preferred chemotherapeutic for glioblastoma, was due to increased NF-κB activity. Aberrant constitutive NF-κB activation is a common event in glioblastoma and can impact both tumor progression and resistance to treatment. Our results suggest that elevated ADAR3 promotes NF-κB activation and a gene expression program that provides a growth advantage to glioblastoma cells.

Recent advances in cancer immunotherapy: Modulation of tumor microenvironment by Toll-like receptor ligands

Immunotherapy is considered a promising approach for cancer treatment. An important strategy for cancer immunotherapy is the use of cancer vaccines, which have been widely used for cancer treatment. Despite the great potential of cancer vaccines for cancer treatment, their therapeutic effects in clinical settings have been limited. The main reason behind the lack of significant therapeutic outcomes for cancer vaccines is believed to be the immunosuppressive tumor microenvironment (TME). The TME counteracts the therapeutic effects of immunotherapy and provides a favorable environment for tumor growth and progression. Therefore, overcoming the immunosuppressive TME can potentially augment the therapeutic effects of cancer immunotherapy in general and therapeutic cancer vaccines in particular. Among the strategies developed for overcoming immunosuppression in TME, the use of toll-like receptor (TLR) agonists has been suggested as a promising approach to reverse immunosuppression. In this paper, we will review the application of the four most widely studied TLR agonists including agonists of TLR3, 4, 7, and 9 in cancer immunotherapy.

Myeloid-derived suppressor cells promote tumor growth and sorafenib resistance by inducing FGF1 upregulation and fibrosis

Background

Methods

Results

Conclusions

The Dynamic Role of NK Cells in Liver Cancers: Role in HCC and HBV Associated HCC and Its Therapeutic Implications

Hepatocellular carcinoma (HCC) remains an important complication of chronic liver disease, especially when cirrhosis occurs. Existing treatment strategies include surgery, loco-regional techniques, and chemotherapy. Natural killer cells are distinctive cytotoxic lymphocytes that play a vital role in fighting tumors and infections. As an important constituent of the innate immune system against cancer, phenotypic and functional deviations of NK cells have been demonstrated in HCC patients who also exhibit perturbation of the NK-activating receptor/ligand axis. The rate of recurrence of tumor-infiltrating and circulating NK cells are positively associated with survival benefits in HCC and have prognostic significance, suggesting that NK cell dysfunction is closely related to HCC progression. NK cells are the first-line effector cells of viral hepatitis and play a significant role by directly clearing virus-infected cells or by activating antigen-specific T cells by producing IFN-γ. In addition, chimeric antigen receptor (CAR) engineered NK cells suggest an exclusive opportunity to produce CAR-NKs with several specificities with fewer side effects. In the present review, we comprehensively discuss the innate immune landscape of the liver, particularly NK cells, and the impact of tumor immune microenvironment (TIME) on the function of NK cells and the biological function of HCC. Furthermore, the role of NK cells in HCC and HBV-induced HCC has also been comprehensively elaborated. We also elaborate on available NK cell-based immunotherapeutic approaches in HCC treatment and summarize current advancements in the treatment of HCC. This review will facilitate researchers to understand the importance of the innate immune landscape of NK cells and lead to devising innovative immunotherapeutic strategies for the systematic treatment of HCC.

ThPOK inhibits the immune escape of gastric cancer cells by inducing STPG1 to inactivate the ERK pathway

Background

Gastric cancer is the second most frequently diagnosed cancer worldwide. Weak immunogenicity helps cancer cells escape from immune elimination and grow into predominant subpopulations. This study aimed to investigate the effect of Zinc finger and BTB domain containing 7B (Zbtb7b, Alias ThPOK) on T cell activation after coculture with gastric cancer cells.

Methods

Cell Counting Kit-8 assay (CCK-8) was performed to explore the viability of gastric cancer cells. Flow cytometry analysis was used to measure CD3+ T cell proliferation and the ratio of activated IFN-γ+ T cells which were co-incubated with gastric cancer cells (HGC-27, SNU-1). The binding between ThPOK and the promoter of its target sperm tail PG-rich repeat containing 1 (STPG1) was explored using ChIP and luciferase reporter assays. Relative gene expression was quantified using RT-qPCR.

Results

ThPOK was expressed at a low level in gastric cancer tissues and cells at mRNA and protein levels. Gastric cancer patients with lower ThPOK expression had poorer prognosis. ThPOK overexpression suppressed gastric cancer cell viability and increased T cell activation. ThPOK served as a transcription factor for STPG1. STPG1 expression was also at a low level in the tissues and cells of gastric cancer. ThPOK positively regulated the mRNA and protein levels of STPG1 in gastric cancer cells. Moreover, ThPOK was demonstrated to bind with STPG1 promoter. STPG1 upregulation also exerted inhibitory effects on gastric cancer cell viability and T cell activation. Additionally, ThPOK and STPG1 were revealed to inactivate the ERK pathway in gastric cancer cells.

Conclusion

ThPOK inhibits gastric cancer cell viability and increases T cell activation by inducing STPG1 to inactivate the ERK pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-022-00485-5.

The effects of Sorafenib and Natural killer cell co-injection in combinational treatment of hepatocellular carcinoma; an in vivo approach

BACKGROUND

Natural killer cells (NKC) and Sorafenib (Sor) are two important agents for the treatment of hepatocellular carcinoma (HCC). Over the past decade, the interaction of Sor and NKC against HCC has been widely challenging. This study aimed to assess the efficacy of NKC & Sor for the treatment of HCC in vivo.

METHODS

Subcutaneous xenograft models of HCC were established in nude mice. For safety assessment of treatment, the kidney and liver functions were analyzed. Paraffin embedded tumor sections were histopathologically studied and immunohistochemistry (IHC) tests were done to evaluate the angiogenesis (CD34) and proliferation (Ki67) indexes. The terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was performed to identify the tumor cells undergoing apoptosis. The serum levels of tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) were measured by enzyme-linked immunosorbent assay (ELISA) and expression levels of major inflammatory cytokines and cytoplasmic granules in xenograft HCC were quantified using real-time PCR.

RESULTS

NKC & Sor significantly inhibited necrosis and apoptosis in tumor cells and increased angiogenesis and proliferation of HCC compared to the monotherapy of NKC or Sor alone. The serum levels of TNF-α, IFN-γ as well as the expression levels of TNF-α, IFN-γ, interleukins (ILs)-1, 6, 10, granzyme-B and perforin in the xenograft HCC tissues of the treated mice with NKC & Sor were significantly lower than those of treated with NKC or Sor alone.

CONCLUSION

Therapy with the specific dosage of NKC & Sor could not inhibit the HCC xenograft growth rate through a synergistic effect in a mouse model of HCC.

Combined Inhibition of TGF-β1-Induced EMT and PD-L1 Silencing Re-Sensitizes Hepatocellular Carcinoma to Sorafenib Treatment

Hepatocellular carcinoma (HCC) is the most common type of primary hepatic malignancy. HCC is one of the leading causes of cancer deaths worldwide. The oral multi-tyrosine kinase inhibitor Sorafenib is the standard first-line therapy in patients with advanced unresectable HCC. Despite the significant survival benefit in HCC patients post treatment with Sorafenib, many patients had progressive disease as a result of acquiring drug resistance. Circumventing resistance to Sorafenib by exploring and targeting possible molecular mechanisms and pathways is an area of active investigation worldwide. Epithelial-to-mesenchymal transition (EMT) is a cellular process allowing epithelial cells to assume mesenchymal traits. HCC tumour cells undergo EMT to become immune evasive and develop resistance to Sorafenib treatment. Immune checkpoint molecules control immune escape in many tumours, including HCC. The aim of this study is to investigate whether combined inhibition of EMT and immune checkpoints can re-sensitise HCC to Sorafenib treatment. Post treatment with Sorafenib, HCC cells PLC/PRF/5 and Hep3B were monitored for induction of EMT and immune checkpoint molecules using quantitative reverse transcriptase (qRT)- PCR, western blot, immunofluorescence, and motility assays. The effect of combination treatment with SB431542, a specific inhibitor of the transforming growth factor (TGF)-β receptor kinase, and siRNA mediated knockdown of programmed cell death protein ligand-1 (PD-L1) on Sorafenib resistance was examined using a cell viability assay. We found that three days of Sorafenib treatment activated EMT with overexpression of TGF-β1 in both HCC cell lines. Following Sorafenib exposure, increase in the expression of PD-L1 and other immune checkpoints was observed. SB431542 blocked the TGF-β1-mediated EMT in HCC cells and also repressed PD-L1 expression. Likewise, knockdown of PD-L1 inhibited EMT. Moreover, the sensitivity of HCC cells to Sorafenib was enhanced by combining a blockade of EMT with SB431542 and knockdown of PD-L1 expression. Sorafenib-induced motility was attenuated with the combined treatment of SB431542 and PD-L1 knockdown. Our findings indicate that treatment with Sorafenib induces EMT and expression of immune checkpoint molecules, which contributes to Sorafenib resistance in HCC cells. Thus, the combination treatment strategy of inhibiting EMT and immune checkpoint molecules can re-sensitise HCC cells to Sorafenib.

Curcumin-enhanced antitumor effects of sorafenib via regulating the metabolism and tumor microenvironment

Curcumin, the main active ingredient of turmeric, is widely used as a kind of food additive and also displays a range of pharmacological activities, such as anti-inflammation, anti-tumor, liver and kidney protection, and so forth. Sorafenib was the first targeted agent against hepatocellular carcinoma (HCC), whose intolerance is related to the promotion of lipid synthesis and epithelial-to-mesenchymal transition (EMT) formation. In this study, biochemical analysis, immune cells composition, the tumor microenvironment, metabolomics, and relative metabolic enzymes and transporters were detected in H22-bearing mice treated with curcumin combined with sorafenib vs. control groups. It was found that curcumin protected against liver cancer progression through reducing the level of alpha fetoprotein in liver tissues, increasing the number of immune cells, like NK cells, inhibiting EMT via the regulation of IL-6/JAK/STAT3 and IL-1β/NF-κB pathways, suppressing anaerobic glycolysis through the inhibition of LDH and HIF-1α, and decreasing the lipid synthesis via the downregulation of FASN, and upregulated the serum HDL-C and mRNA levels of apoA1 in the sorafenib-treated mice. Furthermore, curcumin regulation of the disorder of glycolipid metabolism and EMT was also based on the PI3K/AKT pathway. A docking study was performed and proved the strong affinity between curcumin and the proteins of STAT3, FASN, and AKT. All in all, this experiment provided evidence for the addition of curcumin in the diet to enhance the antitumor efficacy of sorafenib through activating immune function, downregulating EMT, and reversing disorders of the metabolism.

C-X-C chemokine receptor 2 (Cxcr2) promotes hepatocellular carcinoma immune evasion via regulating programmed death-ligand 1 (PD-L1)

Strategies to sensitize hepatocellular carcinomas (HCC) to programmed death-1 (PD1)/programmed death-ligand 1 (PD-L1) inhibitor therapies are important in improving the survival of HCC patients. The aim of the study was to characterize C-X-C chemokine receptor 2 (Cxcr2) as a therapeutic target in HCC and evaluate the effects of Cxcr2 suppression in sensitizing HCC to PD1/PD-L1 inhibitor therapies. To this end, we constructed a Cxcr2-knockout HCC cell line (Hepa1-6 KO) using the CRISPR-Cas9 approach and assessed the tumor growth rate and survival of mice after subcutaneously inoculating Hepa1-6 KO cells in mice. We show that Cxcr2 knockdown does not dramatically inhibit tumor growth and improve mouse survival. In tumor xenografts, the proportion of T cells is not affected but the ratio of M1/M2 macrophage is greatly increased. Cxcr2 knockdown does not alter cell viability but macrophages co-cultured with Hepa1-6 KO cells are shifted to M1 phenotypes compared to WT cells. Hepa-1-6 KO cells exhibit lower levels of PD-L1 expression. c-Myc is suppressed in Hepa1-6 KO cells, which contributes to PD-L1 downregulation. Knockdown of Cxcr2 decreases PD-L1 levels and consequently promotes the shift of macrophages to the M1 phenotype, which is mediated by downregulating c-Myc. In summary, Cxcr2 is a potential target for suppressing immune escape in HCC.

Combination of NK-based immunotherapy and sorafenib against hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most frequent malignancy of the liver, which is considered the fourth leading cause of cancer-related death in the United States. Liver transplant and surgical resection are curative treatments for HCC, but only 10-15% of HCC patients are eligible candidates. The FDA-approved sorafenib is a multi-kinase inhibitor systemic therapy for advanced HCC that extends the overall survival by over 3 months when compared with placebo. Adoptive transfer of Natural Killer (NK) cells holds great promise for clinical cancer treatment. However, only limited clinical benefit has been achieved in cancer patients. Therefore, there is currently considerable interest in development of the combination of sorafenib and NK cells for the treatment of HCC patients. However, the mechanism of how sorafenib affects the function of NK cells remains to be comprehensively clarified. In this paper, we will discuss NK cell-based immunotherapies that are currently under preclinical and clinical investigation and its potential combination with sorafenib for improving the survival of HCC patients.

Double-Stranded RNA Immunomodulators in Prostate Cancer

Relatively simple, synthetic, double-stranded RNAs can be powerful viral pathogen-associated molecular pattern (PAMP) mimics, inducing a panoply of antiviral and antitumor responses that act at multiple stages of host defense. Their mechanisms of action and uses are beginning to be understood, alone, in combination with other therapeutics, or as novel PAMP-adjuvants providing the critical danger signal that has been missing from most cancer and other modern vaccines. Dose, timing, route of administration combinations, and other clinical variables can have a critical impact on immunogenicity. This article reviews advances in the use of polyinosinic-polycytidylic acid and derivatives, in particular poly-ICLC.

Atypical immunometabolism and metabolic reprogramming in liver cancer: Deciphering the role of gut microbiome

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related mortality worldwide. Much recent research has delved into understanding the underlying molecular mechanisms of HCC pathogenesis, which has revealed to be heterogenous and complex. Two major hallmarks of HCC include: (i) a hijacked immunometabolism and (ii) a reprogramming in metabolic processes. We posit that the gut microbiota is a third component in an entanglement triangle contributing to HCC progression. Besides metagenomic studies highlighting the diagnostic potential in the gut microbiota profile, recent research is pinpointing the gut microbiota as an instigator, not just a mere bystander, in HCC. In this chapter, we discuss mechanistic insights on atypical immunometabolism and metabolic reprogramming in HCC, including the examination of tumor-associated macrophages and neutrophils, tumor-infiltrating lymphocytes (e.g., T-cell exhaustion, regulatory T-cells, natural killer T-cells), the Warburg effect, rewiring of the tricarboxylic acid cycle, and glutamine addiction. We further discuss the potential involvement of the gut microbiota in these characteristics of hepatocarcinogenesis. An immediate highlight is that microbiota metabolites (e.g., short chain fatty acids, secondary bile acids) can impair anti-tumor responses, which aggravates HCC. Lastly, we describe the rising 'new era' of immunotherapies (e.g., immune checkpoint inhibitors, adoptive T-cell transfer) and discuss for the potential incorporation of gut microbiota targeted therapeutics (e.g., probiotics, fecal microbiota transplantation) to alleviate HCC. Altogether, this chapter invigorates for continuous research to decipher the role of gut microbiome in HCC from its influence on immunometabolism and metabolic reprogramming.

Acetylsalicylic acid and salicylic acid present anticancer properties against melanoma by promoting nitric oxide-dependent endoplasmic reticulum stress and apoptosis

Melanoma is the most aggressive and fatal type of skin cancer due to being highly proliferative. Acetylsalicylic acid (ASA; Aspirin) and salicylic acid (SA) are ancient drugs with multiple applications in medicine. Here, we showed that ASA and SA present anticancer effects against a murine model of implanted melanoma. These effects were also validated in 3D- and 2D-cultured melanoma B16F10 cells, where the drugs promoted pro-apoptotic effects. In both in vivo and in vitro models, SA and ASA triggered endoplasmic reticulum (ER) stress, which culminates with the upregulation of the pro-apoptotic transcription factor C/EBP homologous protein (CHOP). These effects are initiated by ASA/SA-triggered Akt/mTOR/AMPK-dependent activation of nitric oxide synthase 3 (eNOS), which increases nitric oxide and reactive oxygen species production inducing ER stress response. In the end, we propose that ASA and SA instigate anticancer effects by a novel mechanism, the activation of ER stress.

Poly-ICLC, a multi-functional immune modulator for treating cancer

Immunotherapies have become the first line of treatment for many cancer types. Unfortunately, only a small fraction of patients benefits from these therapies. This low rate of success can be attributed to 3 main barriers: 1) low frequency of anti-tumor specific T cells; 2) lack of infiltration of the anti-tumor specific T cells into the tumor parenchyma and 3) accumulation of highly suppressive cells in the tumor mass that inhibit the effector function of the anti-tumor specific T cells. Thus, the identification of immunomodulators that can increase the frequency and/or the infiltration of antitumor specific T cells while reducing the suppressive capacity of the tumor microenvironment is necessary to ensure the effectiveness of T cell immunotherapies. In this review, we discuss the potential of poly-ICLC as a multi-functional immune modulator for treating cancer and its impact on the 3 above mentioned barriers. We describe the unique capacity of poly-ICLC in stimulating 2 separate pattern recognition receptors, TLR3 and cytosolic MDA5 and the consequences of these activations on cytokines and chemokines production. We emphasize the role of poly-ICLC as an adjuvant in the setting of peptide-based cancer vaccines and in situ tumor vaccination by mimicking natural immune responses to infections. Finally, we summarize the impact of poly-ICLC in enhancing T infiltration into the tumor parenchyma and address the implication of this finding in the clinic.

Myeloid Differentiation Primary Response 88-Cyclin D1 Signaling in Breast Cancer Cells Regulates Toll-Like Receptor 3-Mediated Cell Proliferation

Toll-like receptor 3 (TLR3)-mediated apoptotic changes in cancer cells are well-documented, and hence, several synthetic ligands of TLR3 are being used for adjuvant therapy, but there are reports showing a contradictory effect of TLR3 signaling, which include our previous report that had shown cell proliferation following surface localization of TLR 3. However, the underlying mechanism of cell surface localization of TLR3 and subsequent cell proliferation lacks clarity. This study addresses the TLR3 ligand-mediated signaling cascade that regulates a proliferative effect in breast cancer cells (MDA-MB-231 and T47D) challenged with TLR3 ligand in the presence of myeloid differentiation primary response 88 (MyD88) inhibitor. Evidences were obtained using immunoblotting, coimmunoprecipitation, confocal microscopy, immunocytochemistry, ELISA, and flow cytometry. Results had revealed that TLR3 ligand treatment significantly enhanced breast cancer cell proliferation marked by an upregulated expression of cyclinD1, but the same was suppressed by the addition of MyD88 inhibitor. Also, expression of interleukin 1 receptor-associated kinase 1 (IRAK1)-TNF receptor-associated factor 6 (TRAF6)-transforming growth factor beta-activated kinase 1 (TAK1) was altered in the given TLR3-signaling pathway. Inhibition of MyD88 disrupted the downstream adaptor complex and mediated signaling through the TLR3-MyD88-NF-κB (p65)-IL-6-cyclin D1 pathway. TLR3-mediated alternative signaling of the TLR3-MyD88-IRAK1-TRAF6-TAK1-TAB1-NF-κB axis leads to upregulation of IL6 and cyclin D1. This response is hypothesized to be via the MyD88 gateway that culminates in the proliferation of breast cancer cells. Overall, this study provides first comprehensive evidence on the involvement of canonical signaling of TLR3 using MyD88-cyclin D1-mediated breast cancer cell proliferation. The findings elucidated herein will provide valuable insights into understanding the TLR3-mediated adjuvant therapy in cancer.

Protein tyrosine phosphatase receptor type delta (PTPRD) suppresses the expression of PD-L1 in human hepatocellular carcinoma by down-regulating STAT3

BACKGROUND

Protein tyrosine phosphatase receptor type delta (PTPRD) is a tumor suppressor that is often inactivated in hepatocellular carcinoma (HCC). However, the mechanisms of how PTPRD inhibits HCC are not well understood. Programmed cell death ligand 1 (PD-L1), an immune checkpoint, plays a seminal role in the regulation of carcinogenesis of HCC. The sustained activation of STAT3 is closely related to PTPRD deletion and PD-L1 overexpression; however, whether there is a relationship between PTPRD and PD-L1 expression in HCC has not been investigated. This study aims to investigate the relationship between PTPRD and PD-L1 in HCC samples and illuminate potential new molecular mechanisms of PTPRD effects on PD-L1 in HepG2 cells.

METHODS

We collected 16 pairs of tumorous tissues and adjacent normal tissues from HCC patients. The mRNA and protein expression levels of PTPRD and PD-L1 in the HCC tissues were detected by RT-PCR and Western blot analysis. Next, Spearman's correlation analysis was performed to evaluate the relationship between PTPRD and PD-L1. Then, we transfected the overexpressed or knocked-down PTPRD genes into the HepG2 cell line, and the effects of PTPRD on PD-L1 in HCC cells were evaluated. The activity from the STAT3 and p-STAT3 in the HepG2 cells transfected with PTPRD gene overexpression and knockdown was determined by Western blotting tests.

RESULTS

The expression of PTPRD was significantly down-regulated in the HCC tissues compared with the adjacent control tissues; however, PD-L1 was significantly higher in the HCC tissues. There was a negative correlation between PTPRD and PD-L1 expression in the HCC tissues. PTPRD over-expression significantly inhibited PD-L1 expression; meanwhile, PTPRD depletion promoted PD-L1 expression in the HepG2 cells. Furthermore, PTPRD over-expression significantly inhibited the expression of STAT3 and p-STAT3, while PTPRD depletion promoted these cytokines. Our studies revealed that PTPRD repressed PD-L1 expression in the HepG2 cells, which might occur via the STAT3 pathway.

CONCLUSIONS

The results from our study show that PTPRD and PD-L1 are negatively correlated in HCC tissues. PTPRD suppresses PD-L1 expression in HepG2 cells by down-regulating STAT3. These findings are expected to become a new target for the immunotherapy of HCC.

Sorafenib and Mesenchymal Stem Cell Therapy: A Promising Approach for Treatment of HCC

Hepatocellular carcinoma (HCC) is the fifth most commonly diagnosed cancer and the second most common cause of cancer-related death worldwide. Sorafenib (Sora) is used as a targeted therapy for HCC treatment. Mesenchymal stem cells (MSCs) are applied as a new approach to fight malignancies. Drug resistance and side effects are the major concerns with Sora administration. The effect of using the combination of sorafenib and MSCs on tumor regression in xenograft HCC models was evaluated in this study. Methods and Materials. Human hepatocellular carcinoma cell lines (HepG2) were subcutaneously implanted into the flank of 18 nude mice. The animals were randomly divided into six groups (n = 3); each received Sora (oral), MSCs (IV injection), MSCs (local injection), Sora + MSCs (IV injection), Sora + MSCs (local injection), or no treatment (the control group). Six weeks after tumor implantation, the mice were scarified and tumoral tissues were resected in their entirety. Histopathological and immunohistochemical evaluations were used to measure tumor proliferation and angiogenesis. Apoptotic cells were quantified using the TUNEL assay. Results. No significant difference was found in the tumor grade among the treatment groups. Differentiation features of the tumoral cells were histopathologically insignificant in all the groups. Tumor necrosis was highest in the hpMSC (local) + Sora group. Tumor cell proliferation was reduced in hpMSC (local) + Sora-treated and hpMSC (IV) + Sora-treated mice compared with the other groups. Apoptotic-positive cells occupied a greater proportion in the Sora, hpMSC (IV) + Sora, and hpMSC (local) + Sora groups. Conclusion. A combination of chemotherapy and MSC can yield to more favorable results in the treatment of HCC.

Myeloid derived suppressor cells in cancer, premalignancy and inflammation: A roadmap to cancer immunoprevention

The ultimate success of any form of cancer therapy or cancer prevention depends on its ability to engage the power of the immune system to completely eliminate a growing tumor, lower the life-time tumor risk and establish long-term memory to prevent recurrence or future tumors. For that reason, all therapies but especially immunotherapies depend on the immune health (immunocompetence) of each treated individual. Cancer and chronic illnesses, combined with a usually more advanced age of cancer patients or those at risk for cancer are known to severely suppress multiple antitumor functions of the immune system. Understanding the critical mechanisms controlling and mediating immune suppression can lead to additional therapies to alleviate the effects of those mechanisms and improve the outcome of cancer therapy and prevention. We introduce and review here a highly immunosuppressive cell population found in cancer, precancer, and chronic inflammatory diseases, myeloid derived suppressor cells (MDSC). First described in the setting of advanced cancer, their presence and immunosuppressive activity has been seen more recently in early premalignant lesions and in chronic inflammatory diseases leading to cancer. We describe the detrimental effects of their presence on cancer immunotherapy, immunosurveillance and immunoprevention and review early attempts to develop drugs to eliminate them or reduce their negative impact.

Harnessing cancer immunotherapy during the unexploited immediate perioperative period

The immediate perioperative period (days before and after surgery) is hypothesized to be crucial in determining long-term cancer outcomes: during this short period, numerous factors, including excess stress and inflammatory responses, tumour-cell shedding and pro-angiogenic and/or growth factors, might facilitate the progression of pre-existing micrometastases and the initiation of new metastases, while simultaneously jeopardizing immune control over residual malignant cells. Thus, application of anticancer immunotherapy during this critical time frame could potentially improve patient outcomes. Nevertheless, this strategy has rarely been implemented to date. In this Perspective, we discuss apparent contraindications for the perioperative use of cancer immunotherapy, suggest safe immunotherapeutic and other anti-metastatic approaches during this important time frame and specify desired characteristics of such interventions. These characteristics include a rapid onset of immune activation, avoidance of tumour-promoting effects, no or minimal increase in surgical risk, resilience to stress-related factors and minimal induction of stress responses. Pharmacological control of excess perioperative stress-inflammatory responses has been shown to be clinically feasible and could potentially be combined with immune stimulation to overcome the direct pro-metastatic effects of surgery, prevent immune suppression and enhance immunostimulatory responses. Accordingly, we believe that certain types of immunotherapy, together with interventions to abrogate stress-inflammatory responses, should be evaluated in conjunction with surgery and, for maximal effectiveness, could be initiated before administration of adjuvant therapies. Such strategies might improve the overall success of cancer treatment.

Sorafenib Induces Pyroptosis in Macrophages and Triggers Natural Killer Cell-Mediated Cytotoxicity Against Hepatocellular Carcinoma

Antiangiogenic and cytotoxic effects are considered the principal mechanisms of action of sorafenib, a multitarget kinase inhibitor approved for the treatment of hepatocellular carcinoma (HCC). We report that sorafenib also acts through direct immune modulation, indispensable for its antitumor activity. In vivo cell depletion experiments in two orthotopic HCC mouse models as well as in vitro analysis identified macrophages (MΦ) as the key mediators of the antitumoral effect and demonstrate a strong interdependency of MΦ and natural killer (NK) cells for efficient tumor cell killing. Caspase 1 analysis in sorafenib-treated MΦ revealed an induction of pyroptosis. As a result, cytotoxic NK cells become activated when cocultured with sorafenib-treated MΦ, leading to tumor cell death. In addition, sorafenib was found to down-regulate major histocompatibility complex class I expression of tumor cells, which may reduce the tumor responsiveness to immune checkpoint therapies and favor NK-cell response. In vivo cytokine blocking revealed that sorafenib efficacy is abrogated after inhibition of interleukins 1B and 18. Conclusion: We report an immunomodulatory mechanism of sorafenib involving MΦ pyroptosis and unleashing of an NK-cell response that sets it apart from other spectrum kinase inhibitors as a promising immunotherapy combination partner for the treatment of HCC.

The role of natural killer cells in hepatocellular carcinoma development and treatment: A narrative review

A major obstacle for treatment of HCC is the inadequate efficacy and limitation of the available therapeutic options. Despite the recent advances in developing novel treatment options, HCC still remains one of the major causes of cancer morbidity and mortality around the world. Achieving effective treatment and eradication of HCC is a challenging task, however recent studies have shown that targeting Natural Killer cells, as major regulators of immune system, can help with the complete treatment of HCC, restoration of normal liver function and subsequently higher survival rate of HCC patients. Studies have shown that decrease in the frequency of NK cells, their dysfunction due to several factors such as dysregulation of receptors and their ligands, and imbalance of different types of inhibitory and stimulating microRNA expression is associated with higher rate of HCC progression and development, and poor survival outcome. Here in our review, we mainly focused on the importance of NK cells in HCC development and treatment.

ERK is a Pivotal Player of Chemo-Immune-Resistance in Cancer

The extracellular signal-related kinases (ERKs) act as pleiotropic molecules in tumors, where they activate pro-survival pathways leading to cell proliferation and migration, as well as modulate apoptosis, differentiation, and senescence. Given its central role as sensor of extracellular signals, ERK transduction system is widely exploited by cancer cells subjected to environmental stresses, such as chemotherapy and anti-tumor activity of the host immune system. Aggressive tumors have a tremendous ability to adapt and survive in stressing and unfavorable conditions. The simultaneous resistance to chemotherapy and immune system responses is common, and ERK signaling plays a key role in both types of resistance. In this review, we dissect the main ERK-dependent mechanisms and feedback circuitries that simultaneously determine chemoresistance and immune-resistance/immune-escape in cancer cells. We discuss the pros and cons of targeting ERK signaling to induce chemo-immune-sensitization in refractory tumors.

Myeloid Derived Suppressor Cells Interactions With Natural Killer Cells and Pro-angiogenic Activities: Roles in Tumor Progression

Myeloid-derived suppressor cells (MDSCs) contribute to the induction of an immune suppressive/anergic, tumor permissive environment. MDSCs act as immunosuppression orchestrators also by interacting with several components of both innate and adaptive immunity. Natural killer (NK) cells are innate lymphoid cells functioning as primary effector of immunity, against tumors and virus-infected cells. Apart from the previously described anergy and hypo-functionality of NK cells in different tumors, NK cells in cancer patients show pro-angiogenic phenotype and functions, similar to decidual NK cells. We termed the pro-angiogenic NK cells in the tumor microenvironment "tumor infiltrating NK" (TINKs), and peripheral blood NK cells in cancer patients "tumor associated NK" (TANKs). The contribution of MDSCs in regulating NK cell functions in tumor-bearing host, still represent a poorly explored topic, and even less is known on NK cell regulation of MDSCs. Here, we review whether the crosstalk between MDSCs and NK cells can impact on tumor onset, angiogenesis and progression, focusing on key cellular and molecular interactions. We also propose that the similarity of the properties of tumor associated/tumor infiltrating NK and MDSC with those of decidual NK and decidual MDSCs during pregnancy could hint to a possible onco-fetal origin of these pro-angiogenic leukocytes.

Poly(d,l-lactide-co-glycolide) Nanoparticles as Delivery Platforms for TLR7/8 Agonist-Based Cancer Vaccine

Targeted drug delivery can significantly influence the efficacy of a drug. In the past decades, diverse drug-delivery technologies, including nano- and microparticles, co-crystals, and microneedles have been developed to maximize therapeutic efficacy and minimize undesired side effects of therapeutics. Nanoparticles-submicron-sized drug carriers-have been actively investigated for the delivery of antibiotics, nucleic acids, peptide/proteins, and chemotherapeutics. Recently, nanoparticles have gained attention as a vaccine delivery platform for tumor-associated antigens (TAAs) and/or vaccine adjuvants. Agonists of imidazoquinoline-based Toll-like receptor (TLR) 7/8 are potent cytokine inducers that are used as cancer vaccine adjuvants to elicit robust T-cell response by activating dendritic cells (DCs). Despite their in vitro potency, the translation of TLR7 agonists as cancer vaccine adjuvants in the clinic has been limited by their poor retention at the injection site. Therefore, a formulation that could improve the availability of TLR7/8 agonists to DCs via conventional vaccine administration routes (subcutaneous, intramuscular) can broaden the application of TLR7/8 agonists for cancer immunotherapy. Polymeric nanoparticles fabricated with poly(d,l-lactide-co-glycolide) (PLGA) can be an efficient TLR7/8 agonist delivery platform. PLGA is a biocompatible polymer, and nanoparticles prepared from this polymer are stable in saline and are small enough to be administered by subcutaneous or intramuscular injections. Furthermore, nanoparticulate TLR7/8 delivery can enhance DC uptake and facilitate lymphatic drainage, both of which can enhance the adjuvanticity of TLR7/8 agonists compared with soluble forms. In this review, we discuss the use of PLGA nanoparticles with TLR7/8 agonists for improving cancer immunotherapy.

ACTG1 and TLR3 are biomarkers for alcohol-associated hepatocellular carcinoma

Alcohol consumption is a risk factor for the development of hepatocellular carcinoma (HCC); however, the association between alcohol and HCC remains unknown. The present study aimed to identify key genes related to alcohol-associated HCC to improve the current understanding of the pathology of this disease. Alcohol-associated and non-alcohol-associated HCC samples in the GSE50579 dataset of the Gene Omnibus Database were analyzed to investigate altered gene expression. Integrated bioinformatics methods were employed to clarify the biological functions of the differentially expressed genes (DEGs), including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and protein-protein interactions (PPIs). The present study reported that candidate biomarker micro (mi)RNAs via TargetScan Human 7.1. DEGs and their associated miRNAs (according to bioinformatics analysis) were validated using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Additionally, 284 EGs from the GSE50579 dataset were revealed. In GO term analysis, DEGs were closely associated with the ‘regulation of nucleic acid metabolism’. KEGG pathway analysis indicated that the DEGs were tightly engaged in the ‘VEGF and VEGF receptor signaling network’, ‘proteoglycan syndecan-mediated signaling events’, ‘erbB receptor signaling’ and ‘β1 integrin cell surface interactions’. According to the results of PPI and heat map analysis, the main hub genes were centrin 3 (CETN3), Toll-like receptor 3 (TLR3), receptor tyrosine-protein kinase (ERBB4), heat shock protein family member 8, actin γ1 (ACTG1) and α-smooth muscle actin. it was demonstrated that the ACTG1, TLR3, miR-6819-3p and miRΝΑ (miR)-6877-3P had undefined associations. Furthermore, RT-qPCR analysis revealed that miR-6819-3p and miR-6877-3P may enhance the expression levels of ACTG1 and inhibit the expression levels of TLR3 in alcohol-associated HCC tissues. TLR3 and ACTG1 were proposed as potential biomarkers of alcohol-associated HCC. Investigation into the regulatory functions of miR-6819-3p and miR-6877-3P may provide novel insights into the treatment of alcohol-associated HCC.

Combination therapy of sorafenib with mesenchymal stem cells as a novel cancer treatment regimen in xenograft models of hepatocellular carcinoma

AIM

Hepatocellular carcinoma (HCC) is the most common liver malignancy and the second leading cause of cancer-related deaths in the world. Sorafenib is the first-line treatment of HCC. Although sorafenib has positive effects on the survival of patients, novel therapeutic strategies are needed to extend survival and improve the efficacy of sorafenib. This study combines sorafenib with mesenchymal stem cells (MSCs) as a new approach to enhance the efficacy of sorafenib.

MATERIAL AND METHODS

A subcutaneous xenograft model of HCC, established by human HepG2 cell lines, was implanted into the flank of nude mice and was used to evaluate tumor growth after treatment with sorafenib alone or in combination with MSCs. The aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, and creatinine levels were measured for safety assessment. Histopathological studies were performed using hematoxylin and eosin staining, and immunohistochemistry tests were performed to evaluate proliferation (Ki67) and angiogenesis (CD34). The TUNEL assay was used to detect apoptosis and measure the expression of major inflammatory cytokines (IL-1a, IL-10, and TNF-α) with real-time polymerase chain reaction.

RESULT

Sorafenib, in combination with MSCs, strongly inhibited tumor growth in the xenograft model. Furthermore, the combination therapy significantly inhibited HCC cell proliferation, decreased tumor angiogenesis, and induced apoptosis and maintained antitumor-associated anti-inflammatory effects of MSCs.

CONCLUSION

This combination therapy strategy could be used as a new therapeutic approach to the treatment of HCC that significantly improves upon the results achieved using sorafenib as monotherapy.

Staphylococcal Enterotoxins Dose-Dependently Modulate the Generation of Myeloid-Derived Suppressor Cells

Staphylococcus aureus is one of the major human bacterial pathogens causing a broad spectrum of serious infections. Myeloid-derived suppressor cells (MDSC) represent an innate immune cell subset capable of regulating host-pathogen interactions, yet their role in the pathogenesis of S. aureus infections remains incompletely defined. The aim of this study was to determine the influence of different S. aureus strains and associated virulence factors on human MDSC generation. Using an in vitro MDSC generation assay we demonstrate that low concentrations of supernatants of different S. aureus strains led to an induction of functional MDSC, whereas increased concentrations, conversely, reduced MDSC numbers. The concentration-dependent reduction of MDSC correlated with T cell proliferation and cytotoxicity. Several findings supported a role for staphylococcal enterotoxins in modulating MDSC generation. Staphylococcal enterotoxins recapitulated concentration-dependent MDSC induction and inhibition, T cell proliferation and cytotoxicity, while an enterotoxin-deficient S. aureus strain largely failed to alter MDSC. Taken together, we identified staphylococcal enterotoxins as main modulators of MDSC generation. The inhibition of MDSC generation by staphylococcal enterotoxins might represent a novel therapeutic target in S. aureus infections and beyond in non-infectious conditions, such as cancer.

Combinational immune-cell therapy of natural killer cells and sorafenib for advanced hepatocellular carcinoma: a review

Background

High prevalence of hepatocellular carcinoma (HCC) and typically poor prognosis of this disease that lead to late stage diagnosis when potentially curative therapies are least effective; therefore, development of an effective and systematic treatment is an urgent requirement.

Main body

In this review, several current treatments for HCC patients and their advantages or disadvantages were summarized. Moreover, various recent preclinical and clinical studies about the performances of "two efficient agents, sorafenib or natural killer (NK) cells", against HCC cells were investigated. In addition, the focus this review was on the chemo-immunotherapy approach, correlation between sorafenib and NK cells and their effects on the performance of each other for better suppression of HCC.

Conclusion

It was concluded that combinational therapy with sorafenib and NK cells might improve the outcome of applied therapeutic approaches for HCC patients. Finally, it was also concluded that interaction between sorafenib and NK cells is dose and time dependent, therefore, a careful dose and time optimizing is necessary for development of a combinational immune-cell therapy.

Premature activation of Cdk1 leads to mitotic events in S phase and embryonic lethality

Cell cycle regulation, especially faithful DNA replication and mitosis, are crucial to maintain genome stability. Cyclin-dependent kinase (CDK)/cyclin complexes drive most processes in cellular proliferation. In response to DNA damage, cell cycle surveillance mechanisms enable normal cells to arrest and undergo repair processes. Perturbations in genomic stability can lead to tumor development and suggest that cell cycle regulators could be effective targets in anticancer therapy. However, many clinical trials ended in failure due to off-target effects of the inhibitors used. Here, we investigate in vivo the importance of WEE1- and MYT1-dependent inhibitory phosphorylation of mammalian CDK1. We generated Cdk1^AF knockin mice, in which two inhibitory phosphorylation sites are replaced by the non-phosphorylatable amino acids T14A/Y15F. We uncovered that monoallelic expression of CDK1^AF is early embryonic lethal in mice and induces S phase arrest accompanied by γH2AX and DNA damage checkpoint activation in mouse embryonic fibroblasts (MEFs). The chromosomal fragmentation in Cdk1^AF MEFs does not rely on CDK2 and is partly caused by premature activation of MUS81-SLX4 structure-specific endonuclease complexes, as well as untimely onset of chromosome condensation followed by nuclear lamina disassembly. We provide evidence that tumor development in liver expressing CDK1^AF is inhibited. Interestingly, the regulatory mechanisms that impede cell proliferation in CDK1^AF expressing cells differ partially from the actions of the WEE1 inhibitor, MK-1775, with p53 expression determining the sensitivity of cells to the drug response. Thus, our work highlights the importance of improved therapeutic strategies for patients with various cancer types and may explain why some patients respond better to WEE1 inhibitors.

CD14+ CD15- HLA-DR- myeloid-derived suppressor cells impair antimicrobial responses in patients with acute-on-chronic liver failure

OBJECTIVE

Immune paresis in patients with acute-on-chronic liver failure (ACLF) accounts for infection susceptibility and increased mortality. Immunosuppressive mononuclear CD14⁺HLA-DR^- myeloid-derived suppressor cells (M-MDSCs) have recently been identified to quell antimicrobial responses in immune-mediated diseases. We sought to delineate the function and derivation of M-MDSC in patients with ACLF, and explore potential targets to augment antimicrobial responses.

DESIGN

Patients with ACLF (n=41) were compared with healthy subjects (n=25) and patients with cirrhosis (n=22) or acute liver failure (n=30). CD14⁺CD15^-CD11b⁺HLA-DR^- cells were identified as per definition of M-MDSC and detailed immunophenotypic analyses were performed. Suppression of T cell activation was assessed by mixed lymphocyte reaction. Assessment of innate immune function included cytokine expression in response to Toll-like receptor (TLR-2, TLR-4 and TLR-9) stimulation and phagocytosis assays using flow cytometry and live cell imaging-based techniques.

RESULTS

Circulating CD14⁺CD15^-CD11b⁺HLA-DR^- M-MDSCs were markedly expanded in patients with ACLF (55% of CD14+ cells). M-MDSC displayed immunosuppressive properties, significantly decreasing T cell proliferation (p=0.01), producing less tumour necrosis factor-alpha/interleukin-6 in response to TLR stimulation (all p<0.01), and reduced bacterial uptake of Escherichia coli (p<0.001). Persistently low expression of HLA-DR during disease evolution was linked to secondary infection and 28-day mortality. Recurrent TLR-2 and TLR-4 stimulation expanded M-MDSC in vitro. By contrast, TLR-3 agonism reconstituted HLA-DR expression and innate immune function ex vivo.

CONCLUSION

Immunosuppressive CD14⁺HLA-DR^- M-MDSCs are expanded in patients with ACLF. They were depicted by suppressing T cell function, attenuated antimicrobial innate immune responses, linked to secondary infection, disease severity and prognosis. TLR-3 agonism reversed M-MDSC expansion and innate immune function and merits further evaluation as potential immunotherapeutic agent.

Targeting VEGF/VEGFR to Modulate Antitumor Immunity

In addition to the crucial role in promoting the growth of tumor vessels, vascular endothelial growth factor (VEGF) is also immunosuppressive. VEGF can inhibit the function of T cells, increase the recruitment of regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs), and hinder the differentiation and activation of dendritic cells (DCs). Recent studies have investigated the role of antiangiogenic agents in antitumor immunity, especially in recent 3 years. Therefore, it is necessary to update the role of targeting VEGF/VEGFR in antitumor immunity. In this review, we focus on the latest clinical and preclinical findings on the modulatory role of antiangiogenic agents targeting VEGF/VEGFR in immune cells, including effector T cells, Tregs, MDSCs, DCs, tumor-associated macrophages, and mast cells. Our review will be potentially helpful for the development of combinations of angiogenesis inhibitors with immunological modulators.

Combination of sorafenib and cytokine-induced killer cells in metastatic renal cell carcinoma: a potential regimen

Metastatic renal cell carcinoma (MRCC) exhibits primary resistance to both chemotherapy and radiotherapy. As an immunogenic cancer, MRCC is relatively sensitive to immunotherapy such as that with cytokines, immune checkpoint inhibitors and adoptive T-cell therapy. In addition, many targeted agents developed over the past decade exhibit greater efficacy than cytokines and have become the standard first-line therapy for MRCC. Several preclinical studies have shown that the targeted agent sorafenib possesses an immunomodulation function and may be suitable for combination with immunotherapy. Here, combinatorial therapy consisting of sorafenib and cytokine-induced killer cell immunotherapy was administered to an MRCC patient resulting in a synergistic effect without serious adverse effects. These results suggest a potential combinatorial regimen for MRCC patients.

Combinatorial treatment with polyI:C and anti-IL6 enhances apoptosis and suppresses metastasis of lung cancer cells

Activation of TLR3 stimulates cancer cell apoptosis and triggers secretion of inflammatory cytokines. PolyI:C, a TLR3 agonist, activates immune cells and regresses metastatic lung cancer in vivo. Although polyI:C reportedly kills lung carcinomas, the mechanism remains elusive. Here, we demonstrated that polyI:C suppressed the proliferation and survival of metastatic (NCI-H358 and NCI-H292) and non-metastatic (A549) lung cancer cells. Notably, A549, NCI-H292 and NCI-H358 which are inducible by polyI:C, expressed low-to-medium level of TLR3 protein, and were susceptible to polyI:C treatment. By contrast, NCI-H1299, which endogenously expresses high level of TLR3 protein, was insensitive to polyI:C. We showed that polyI:C stimulated pro-inflammatory cytokines associated with survival and metastasis in a cell type-specific manner. While A549 and NCI-H292 released high levels of IL6, IL8 and GRO, the NCI-H358 cells endogenously secretes abundant levels of these cytokines, and was not further induced by polyI:C. Thus, NCI-H358 was resistant to the inhibition of cytokine-dependent metastasis. NCI-H1299, which was unresponsive to polyI:C, did not produce any of the pro-inflammatory cytokines. Treatment of A549 with a combination of polyI:C and anti-IL6 antibody significantly decreased IL6 production, and enhanced polyI:C-mediated killing and suppression of oncogenicity and metastasis. While polyI:C stimulated the phosphorylation of STAT3 and JAK2, blockade of these proteins enhanced polyI:C-mediated suppression of survival and metastasis. Taken together, polyI:C alone provoked apoptosis of lung cancer cells that express low-to-medium levels of functional TLR3 protein. The combinatorial treatment with polyI:C and anti-IL6 enhanced polyI:C-mediated anticancer activities through IL6/JAK2/STAT3 signalling, and apoptosis via TLR3-mediated caspase 3/8 pathway.

Bufalin Suppresses Migration and Invasion of Hepatocellular Carcinoma Cells Elicited by Poly (I:C) Therapy

The Toll-like receptor 3 (TLR3) agonists as polyriboinosinic–polyribocytidylic acid (poly (I:C)) have been implicated as potential immunotherapy adjuvant for cancer whereas the exact roles of TLR3 agonists in hepatocellular carcinoma (HCC) treatment have not been clearly evaluated. In consistent with previous reports, we found that poly (I:C) triggering of TLR3 inhibited cell proliferation and induced apoptosis in HCC cells. However, poly (I:C), when used at lower concentration that cannot remarkably inhibit proliferation and induce apoptosis in HCC cells, enhanced the migration and invasion in vitro and the metastasis in vivo. More importantly, we found that bufalin, a prominent component of toad venom, could suppress poly (I:C)-inspired migration, invasion and metastasis of HCC cells despite that bufalin could not potentiate poly (I:C)-induced inhibition of proliferation and induction of apoptosis. In MHCC97 H cells, bufalin impaired poly (I:C)-induced activation of Tank-binding kinase 1 (TBK1) and interferon regulatory factor 3 (IRF3) pathway and NF-κB pathway. Inhibitor for TBK1 but not NF-κB suppressed poly (I:C)-inspired migration and invasion, which was further supported by using TBK1 deficient (Tbk1^–/–) cells. In another model using poly (I:C) transfection, bufalin could also suppress the migration and invasion of HCC cells, which was not observed in Tbk1^–/– MHCC97 H cells. Our data suggest that bufalin can suppress the metastasis of HCC cells in poly (I:C) therapy by impairing TBK1 activation, indicating that bufalin may be used in combination with poly (I:C) therapy in HCC treatment for the sake of reversing poly (I:C)-triggered metastasis of HCC cells.

ESCMID Study Group for Infections in Compromised Hosts (ESGICH) Consensus Document on the safety of targeted and biological therapies: an infectious diseases perspective (Cell surface receptors and associated signaling pathways)

BACKGROUND

The present review is part of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Infections in Compromised Hosts (ESGICH) consensus document on the safety of targeted and biologic therapies.

AIMS

To review, from an infectious diseases perspective, the safety profile of therapies targeting cell surface receptors and associated signaling pathways among cancer patients and to suggest preventive recommendations.

SOURCES

Computer-based Medline searches with MeSH terms pertaining to each agent or therapeutic family.

CONTENT

Vascular endothelial growth factor (VEGF)-targeted agents (bevacizumab and aflibercept) are associated with a meaningful increase in the risk of infection, likely due to drug-induced neutropaenia, although no clear benefit is expected from the universal use of anti-infective prophylaxis. VEGF tyrosine kinase inhibitors (i.e. sorafenib or sunitinib) do not seem to significantly affect host's susceptibility to infection, and universal anti-infective prophylaxis is not recommended either. Anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (cetuximab or panitumumab) induce neutropaenia and secondary skin and soft tissue infection in cases of severe papulopustular rash. Systemic antibiotics (doxycycline or minocycline) should be administered to prevent the latter complication, whereas no recommendation can be established on the benefit from antiviral, antifungal or anti-Pneumocystis prophylaxis. A lower risk of infection is reported for anti-ErbB2/HER2 monoclonal antibodies (trastuzumab and pertuzumab) and ErbB receptor tyrosine kinase inhibitors (including dual-EGFR/ErbB2 inhibitors such as lapatinib or neratinib) compared to conventional chemotherapy, presumably as a result of the decreased occurrence of drug-induced neutropaenia.

IMPLICATIONS

With the exception of VEGF-targeted agents, the overall risk of infection associated with the reviewed therapies seems to be low.

Alternative treatments in advanced hepatocellular carcinoma patients with progressive disease after sorafenib treatment: a prospective multicenter cohort study

Sorafenib is an oral multikinase inhibitor that has been approved to treat advanced hepatocellular carcinoma (HCC), though it is unclear how much benefit advanced HCC patients with progressive disease (PD) derive from sorafenib treatment. This study aimed to assess survival risk factors and evaluate therapeutic strategies for advanced HCC patients with PD after sorafenib treatment. We analyzed the clinical data and treatment outcomes for 315 consecutive advanced HCC patients treated with sorafenib. Univariate analyses of overall survival identified therapeutic effect as an independent risk factor in all patients. Among all patients, 141 developed PD. Of those, 58 (41%) were treated with sorafenib monotherapy, 70 (50%) with agents other than sorafenib, and 13 (9%) were not treated at all. The median survival time was 6.1 months for PD patients with sorafenib monotherapy and 12.2 months for those administered alternative treatments (p < 0.0001). Our results indicated that sorafenib treatment may have negative long-term therapeutic effects in advanced HCC patients with PD, and that alternative treatments should be considered for these patients after sorafenib administration.

Poly(I:C) primes primary human glioblastoma cells for an immune response invigorated by PD-L1 blockade

Prognosis of glioblastoma remains dismal, underscoring the need for novel therapies. Immunotherapy is generating promising results, but requires combination strategies to unlock its full potential. We investigated the immunomodulatory capacities of poly(I:C) on primary human glioblastoma cells and its combinatorial potential with programmed death ligand (PD-L) blockade. In our experiments, poly(I:C) stimulated expression of both PD-L1 and PD-L2 on glioblastoma cells, and a pro-inflammatory secretome, including type I interferons (IFN) and chemokines CXCL9, CXCL10, CCL4 and CCL5. IFN-β was partially responsible for the elevated PD-1 ligand expression on these cells. Moreover, real-time PCR and chloroquine-mediated blocking experiments indicated that poly(I:C) triggered Toll-like receptor 3 to elicit its effect. Cocultures of poly(I:C)-treated glioblastoma cells with peripheral blood mononuclear cells enhanced lymphocytic activation (CD69, IFN-γ) and cytotoxic capacity (CD107a, granzyme B). Additional PD-L1 blockade further propagated immune activation. Besides activating immunity, poly(I:C)-treated glioblastoma cells also doubled the attraction of CD8⁺ T cells, and to a lesser extent CD4⁺ T cells, via a mechanism which included CXCR3 and CCR5 ligands. Our results indicate that by triggering glioblastoma cells, poly(I:C) primes the tumor microenvironment for an immune response. Secreted cytokines allow for immune activation while chemokines attract CD8⁺ T cells to the front, which are postulated as a prerequisite for effective PD-1/PD-L1 blockade. Accordingly, additional blockade of the concurrently elevated tumoral PD-L1 further reinforces the immune activation. In conclusion, our data proposes poly(I:C) treatment combined with PD-L1 blockade to invigorate the immune checkpoint inhibition response in glioblastoma.

Delivery of the TLR ligand poly(I:C) to liver cells in vitro and in vivo by calcium phosphate nanoparticles leads to a pronounced immunostimulation

The selective activation of the immune system is a concurrent problem in the treatment of persistent diseases like viral infections (e.g. hepatitis). For the delivery of the toll-like receptor ligand poly(I:C), an immunostimulatory action was discovered earlier by hydrodynamic injection. However, this technique is not clinically transferable to human patients. A modular system where the immunoactive toll-like-receptor ligand 3 (TLR-3) poly(I:C) was incorporated into calcium phosphate nanoparticles was developed. The nanoparticles had a hydrodynamic diameter of 275nm and a zeta potential of +20mV, measured by dynamic light scattering. The diameter of the solid core was 120nm by scanning electron microscopy. In vitro, the nanoparticle uptake was investigated after 1 and 24h of incubation of THP-1 cells (macrophages) with nanoparticles by fluorescence microscopy. After intravenous injection into BALB/c and C57BL/6J mice, respectively, the in vivo uptake was especially prominent in lung and liver, 1 and 3h after the injection. Pronounced immunostimulatory effects of the nanoparticles were found in vitro with primary liver cells, i.e. Kupffer cells (KC) and liver sinusoidal endothelial cells (LSEC) from wild-type C57BL/6J mice. Thus, they represent a suitable alternative to hydrodynamic injection treatments for future vaccination concepts.

STATEMENT OF SIGNIFICANCE

The selective activation of the immune system is a concurrent problem in the treatment of persistent diseases like viral infections (e.g. hepatitis). For the delivery of the toll-like receptor ligand poly(I:C), an immunostimulatory action has been discovered earlier by hydrodynamic injection. However, this technique is not clinically transferable to human patients. We have developed a modular system where poly(I:C) was incorporated into calcium phosphate nanoparticles. The uptake into relevant liver cells was studied both in vitro and in vivo. After intravenous injection into mice, the in vivo uptake was especially prominent in lung and liver, 1 and 3h after the injection. The corresponding strong immune reaction proves their high potential to turn up the immune system, e.g. against viral infections, without adverse side reactions.

Immunotherapy of Hepatocellular Carcinoma: Facts and Hopes

Treatment of patients with hepatocellular carcinoma (HCC) in the advanced stage remains a great challenge, with very few drugs approved. After decades of failure of immune therapies, immune checkpoint inhibitors have emerged as potentially effective treatments for patients with HCC in the advanced stage. Immune checkpoints, including human cancer, cytotoxic T-lymphocyte protein 4 (CTLA-4), and programmed cell death protein 1 (PD-1), are surface proteins expressed in a variety of immune cells and mostly provide immunosuppressive signals. Monoclonal antibodies able to block these molecules have shown antitumor activity against a wide spectrum of human cancers. Clinical experience with checkpoint inhibitors in HCC includes early trials with the anti-CTLA-4 agent tremelimumab and a large phase II trial with the anti-PD-1 agent nivolumab. The latter has shown strong activity particularly as second-line therapy, both in terms of tumor response and patient survival. At least three topics should be the focus of future research: (i) the search for activity in patients at less-advanced stages, including the adjuvant treatment of patients with resectable or ablatable tumors; (ii) the enhanced efficacy of combination therapies, including particularly the combination with those targeted and locoregional therapies that may have a synergistic effect or act upon mechanisms of primary or acquired resistance to checkpoint inhibitors; and (iii) the identification of clinical features and serum or tissue biomarkers that would allow a better patient selection for individual treatments. Hopefully, ongoing trials will help to design better treatments in the future. Clin Cancer Res; 24(7); 1518-24. ©2017 AACR.

Natural Killer Cell Response to Chemotherapy-Stressed Cancer Cells: Role in Tumor Immunosurveillance

Natural killer (NK) cells are innate cytotoxic lymphoid cells that actively prevent neoplastic development, growth, and metastatic dissemination in a process called cancer immunosurveillance. An equilibrium between immune control and tumor growth is maintained as long as cancer cells evade immunosurveillance. Therapies designed to kill cancer cells and to simultaneously sustain host antitumor immunity are an appealing strategy to control tumor growth. Several chemotherapeutic agents, depending on which drugs and doses are used, give rise to DNA damage and cancer cell death by means of apoptosis, immunogenic cell death, or other forms of non-apoptotic death (i.e., mitotic catastrophe, senescence, and autophagy). However, it is becoming increasingly clear that they can trigger additional stress responses. Indeed, relevant immunostimulating effects of different therapeutic programs include also the activation of pathways able to promote their recognition by immune effector cells. Among stress-inducible immunostimulating proteins, changes in the expression levels of NK cell-activating and inhibitory ligands, as well as of death receptors on tumor cells, play a critical role in their detection and elimination by innate immune effectors, including NK cells. Here, we will review recent advances in chemotherapy-mediated cellular stress pathways able to stimulate NK cell effector functions. In particular, we will address how these cytotoxic lymphocytes sense and respond to different types of drug-induced stresses contributing to anticancer activity.

Program death-1 immune checkpoint and tumor microenvironment in malignant liver tumors

Hepatic malignancies are one of the leading causes of cancer death globally. Considering the limited efficacy of current standard treatments in management of patients with advanced liver cancers, there has been a growing interest in identifying novel therapies. Despite achieving promising results in initial clinical trials, the therapeutic benefit of immunotherapy is limited due to strong immune-tolerogenic characteristics of liver tumors. Therapeutic regimens that impede tumor immunosuppressive mechanisms or elaborate tumor-specific immunity may improve clinical outcomes of patients with liver malignancies. Programmed cell death 1 (PD-1), an inhibitory checkpoint molecule, and its ligands (PD-L1 and -L2) are the main mediators of immunosuppression within the tumor microenvironment. The expression level of PD-1/PD-L1 may act as a biomarker to predict disease progression, as well as long-term survival. Furthermore, early trials have demonstrated the efficacy and safety of targeting PD-1/PD-L1 as an emerging field in the management of patients with advanced hepatocellular carcinoma. We herein review the role of PD-1/PD-L1 in the pathogenesis of liver malignancies, as well as its potential diagnostic and therapeutic implications.

Therapeutic vaccine to cure large mouse hepatocellular carcinomas

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide with limited therapeutic options. Here we report the development of a therapeutic vaccination regimen (shortened as ‘TheraVac’) consisting of intratumoral delivery of high-mobility group nucleosome-binding protein 1 (HMGN1), R848/resiquimod, and one of the checkpoint inhibitors (e.g. anti-CTLA4, anti-PD-L1, or low dose of Cytoxan). C57BL/6 mice harboring large (approximately 1 cm in diameter) established subcutaneous Hepa1-6 hepatomas were cured by intratumoral injections of TheraVac and became tumor-free long-term survivors. Importantly, the resultant tumor-free mice were resistant to re-challenge with Hepa1-6 hepatoma, not B16 melanoma, demonstrating the acquisition of hepatoma-specific immunity in the absence of any administered tumor antigen. Mechanistic studies showed that upon treatment with TheraVac, Hepa1-6-bearing mice generated increased Hepa1-6-specific CTLs in the draining lymph nodes and showed greatly upregulated expression of CXCL9, CXCL10, and IFN-γ and elevated infiltration of T lymphocytes in tumor tissues. Treatment of large Hepa1-6 hepatomas on one mouse flank also eliminated smaller (approximately 0.5 cm in diameter) hepatomas implanted on the other flank. Thus, TheraVac has potential as a curative immunotherapeutic regimen for the treatment of human HCC.