Targeting carnitine palmitoyl transferase 1A (CPT1A) induces ferroptosis and synergizes with immunotherapy in lung cancer.

Despite the successful application of immune checkpoint therapy, no response or recurrence is typical in lung cancer. Cancer stem cells (CSCs) have been identified as a crucial player in immunotherapy-related resistance. Ferroptosis, a form of cell death driven by iron-dependent lipid peroxidation, is highly regulated by cellular metabolism remolding and has been shown to have synergistic effects when combined with immunotherapy. Metabolic adaption of CSCs drives tumor resistance, yet the mechanisms of their ferroptosis defense in tumor immune evasion remain elusive. Here, through metabolomics, transcriptomics, a lung epithelial-specific Cpt1a-knockout mouse model, and clinical analysis, we demonstrate that CPT1A, a key rate-limiting enzyme of fatty acid oxidation, acts with L-carnitine, derived from tumor-associated macrophages to drive ferroptosis-resistance and CD8+ T cells inactivation in lung cancer. Mechanistically, CPT1A restrains ubiquitination and degradation of c-Myc, while c-Myc transcriptionally activates CPT1A expression. The CPT1A/c-Myc positive feedback loop further enhances the cellular antioxidant capacity by activating the NRF2/GPX4 system and reduces the amount of phospholipid polyunsaturated fatty acids through ACSL4 downregulating, thereby suppressing ferroptosis in CSCs. Significantly, targeting CPT1A enhances immune checkpoint blockade-induced anti-tumor immunity and tumoral ferroptosis in tumor-bearing mice. The results illustrate the potential of a mechanism-guided therapeutic strategy by targeting a metabolic vulnerability in the ferroptosis of CSCs to improve the efficacy of lung cancer immunotherapy.

Chimeric antigen receptor macrophages activated through TLR4 or IFN-γ receptors suppress breast cancer growth by targeting VEGFR2.

Chimeric antigen receptor macrophage (CAR-M) is a promising immunotherapy strategy of anti-tumor due to its high infiltration, direct phagocytosis of tumor cells, immunomodulation of tumor microenvironment (TME) and linkage of innate and adaptive immunity. Here a series of novelly designed CAR-Ms by targeting vascular endothelial growth factor receptor-2 (VEGFR2), which highly expressed in tumor cells and TME, were evaluated. Their activation signals were transduced by Tlr4 or Ifn-γ receptors either alone or in combination, which were designed to mediate M1 polarization of macrophages as the downstream of lipopolysaccharide or Ifn-γ that had been widely reported. Our results showed that VEGFR2-targeting CAR-Ms could be activated under the stimulation of VEGFR2-expressing cells. They exhibited higher expression of CD86, MHCII and TNF-α in vitro and enhanced tumor suppressive abilities in vivo. Implantation of these CAR-Ms into 4T1 breast cancer-bearing mice could obviously inhibit the progression of tumor without significant toxic side effects, especially the group of mmC in which constructed with Tlr4 as the intracellular domain of CAR. In conclusion, this research provides a promising design of CAR that induce macrophages activation by Tlr4 and/or Ifn-γ receptors, and these CAR-Ms could effectively inhibit tumor growth through targeting VEGFR2.

Exosomal miRNA-223-3p derived from tumor associated macrophages promotes pulmonary metastasis of breast cancer 4T1 cells.

Research about the effect of exosomes derived from tumor associated macrophages (TAM-exos) in the distant organ metastasis of breast cancer is limited. In this study, we found that TAM-exos could promote the migration of 4T1 cells. Through comparing the expression of microRNAs in 4T1 cells, TAM-exos, and exosomes from bone marrow derived macrophages (BMDM-exos) by sequencing, miR-223-3p and miR-379-5p were screened out as two noteworthy differentially expressed microRNAs. Furthermore, miR-223-3p was confirmed to be the reason for the improved migration and metastasis of 4T1 cells. The expression of miR-223-3p was also increased in 4T1 cells isolated from the lung of tumor-bearing mice. Cbx5, which has been reported to be closely related with metastasis of breast cancer, was identified to be the target of miR-223-3p. Based on the information of breast cancer patients from online databases, miR-223-3p had a negative correlation with the overall survival rate of breast cancer patients within a three-year follow-up, while Cbx5 showed an opposite relationship. Taken together, miR-223-3p in TAM-exos can be delivered into 4T1 cells and exosomal miR-223-3p promotes pulmonary metastasis of 4T1 cells by targeting Cbx5.

The G allele of SNP rs3922 reduces the binding affinity between IGF2BP3 and CXCR5 correlating with a lower antibody production.

Effective vaccines that function through humoral immunity seek to produce high-affinity antibodies. Our previous research identified the single-nucleotide polymorphism rs3922G in the 3'UTR of CXCR5 as being associated with nonresponsiveness to the hepatitis B vaccine. The differential expression of CXCR5 between the dark zone (DZ) and light zone (LZ) is critical for organizing the functional structure of the germinal center (GC). In this study, we report that the RNA-binding protein IGF2BP3 can bind to CXCR5 mRNA containing the rs3922 variant to promote its degradation via the nonsense-mediated mRNA decay pathway. Deficiency of IGF2BP3 leads to increased CXCR5 expression, which results in the disappearance of CXCR5 differential expression between DZ and LZ, disorganized GCs, aberrant somatic hypermutations, and reduced production of high-affinity antibodies. Furthermore, the affinity of IGF2BP3 for the rs3922G-containing sequence is lower than that for the rs3922A counterpart, which may explain the nonresponsiveness to the hepatitis B vaccination. Together, our findings suggest that IGF2BP3 plays a crucial role in the production of high-affinity antibodies in the GC by binding to the rs3922-containing sequence to regulate CXCR5 expression.

Recent Advances in the Development of Toll-like Receptor Agonist-Based Vaccine Adjuvants for Infectious Diseases.

Vaccines are powerful tools for controlling microbial infections and preventing epidemic diseases. Efficient inactive, subunit, or viral-like particle vaccines usually rely on a safe and potent adjuvant to boost the immune response to the antigen. After a slow start, over the last decade there has been increased developments on adjuvants for human vaccines. The development of adjuvants has paralleled our increased understanding of the molecular mechanisms for the pattern recognition receptor (PRR)-mediated activation of immune responses. Toll-like receptors (TLRs) are a group of PRRs that recognize microbial pathogens to initiate a host's response to infection. Activation of TLRs triggers potent and immediate innate immune responses, which leads to subsequent adaptive immune responses. Therefore, these TLRs are ideal targets for the development of effective adjuvants. To date, TLR agonists such as monophosphoryl lipid A (MPL) and CpG-1018 have been formulated in licensed vaccines for their adjuvant activity, and other TLR agonists are being developed for this purpose. The COVID-19 pandemic has also accelerated clinical research of vaccines containing TLR agonist-based adjuvants. In this paper, we reviewed the agonists for TLR activation and the molecular mechanisms associated with the adjuvants' effects on TLR activation, emphasizing recent advances in the development of TLR agonist-based vaccine adjuvants for infectious diseases.

Sharpening up tumor microenvironment to enhance the efficacy of immune checkpoint blockade on head and neck cancer using a CpG-oligodeoxynucleotide.

Head and neck cancers are a type of life-threatening cancers characterized by an immunosuppressive tumor microenvironment. Only less than 20% of the patients respond to immune checkpoint blockade therapy, indicating the need for a strategy to increase the efficacy of immunotherapy for this type of cancers. Previously, we identified a type B CpG-oligodeoxynucleotide (CpG-ODN) called CpG-2722, which has the universal activity of eliciting an immune response in grouper, mouse, and human cells. In this study, we further characterized and compared its cytokine-inducing profiles with different types of CpG-ODNs. The antitumor effect of CpG-2722 was further investigated alone and in combination with an immune checkpoint inhibitor in a newly developed syngeneic orthotopic head and neck cancer animal model. Along with other inflammatory cytokines, CpG-2722 induces the gene expressions of interleukin-12 and different types of interferons, which are critical for the antitumor response. Both CpG-2722 and anti-programmed death (PD)-1 alone suppressed tumor growth. Their tumor suppression efficacies were further enhanced when CpG-2722 and anti-PD-1 were used in combination. Mechanistically, CpG-2722 shaped a tumor microenvironment that is favorable for the action of anti-PD-1, which included promoting the expression of different cytokines such as IL-12, IFN-ß, and IFN-γ, and increasing the presence of plasmacytoid dendritic cells, M1 macrophages, and CD8 positive T cells. Overall, CpG-2722 provided a priming effect for CD8 positive T cells by sharpening the tumor microenvironment, whereas anti-PD-1 released the brake for their tumor-killing effect, resulting in an enhanced efficacy of the combined CpG-2722 and anti-PD-1.

Lactate Dehydrogenase-A (LDH-A) Preserves Cancer Stemness and Recruitment of Tumor-Associated Macrophages to Promote Breast Cancer Progression.

Increasing evidence reveals that breast cancer stem cells (BCSCs) subtypes with distinct properties are regulated by their abnormal metabolic changes; however, the specific molecular mechanism and its relationship with tumor microenvironment (TME) are not clear. In this study, we explored the mechanism of lactate dehydrogenase A (LDHA), a crucial glycolytic enzyme, in maintaining cancer stemness and BCSCs plasticity, and promoting the interaction of BCSCs with tumor associated macrophages (TAMs). Firstly, the expression of LDHA in breast cancer tissues was much higher than that in adjacent tissues and correlated with the clinical progression and prognosis of breast cancer patients based on The Cancer Genome Atlas (TCGA) data set. Moreover, the orthotopic tumor growth and pulmonary metastasis were remarkable inhibited in mice inoculated with 4T1-shLdha cells. Secondly, the properties of cancer stemness were significantly suppressed in MDA-MB-231-shLDHA or A549-shLDHA cancer cells, including the decrease of ALDH+ cells proportion, the repression of sphere formation and cellular migration, and the reduction of stemness genes (SOX2, OCT4, and NANOG) expression. However, the proportion of ALDH+ cells (epithelial-like BCSCs, E-BCSCs) was increased and the proportion of CD44+ CD24- cells (mesenchyme-like BCSCs, M-BCSCs) was decreased after LDHA silencing, suggesting a regulatory role of LDHA in E-BCSCs/M-BCSCs transformation in mouse breast cancer cells. Thirdly, the expression of epithelial marker E-cadherin, proved to interact with LDHA, was obviously increased in LDHA-silencing cancer cells. The recruitment of TAMs and the secretion of CCL2 were dramatically reduced after LDHA was knocked down in vitro and in vivo. Taken together, LDHA mediates a vicious cycle of mutual promotion between BCSCs plasticity and TAMs infiltration, which may provide an effective treatment strategy by targeting LDHA for breast cancer patients.

Erratum: CCL16 maintains stem cell-like properties in breast cancer by activating CCR2/GSK3ß/ß-catenin/OCT4 axis: Erratum.

[This corrects the article DOI: 10.7150/thno.51000.].

Targeting macrophages in cancer immunotherapy.

Immunotherapy is regarded as the most promising treatment for cancers. Various cancer immunotherapies, including adoptive cellular immunotherapy, tumor vaccines, antibodies, immune checkpoint inhibitors, and small-molecule inhibitors, have achieved certain successes. In this review, we summarize the role of macrophages in current immunotherapies and the advantages of targeting macrophages. To better understand and make better use of this type of cell, their development and differentiation characteristics, categories, typical markers, and functions were collated at the beginning of the review. Therapeutic strategies based on or combined with macrophages have the potential to improve the treatment efficacy of cancer therapies.

MicroRNA-3613-3p functions as a tumor suppressor and represents a novel therapeutic target in breast cancer.

BACKGROUND: MicroRNAs have been reported to participate in tumorigenesis, treatment resistance, and tumor metastasis. Novel microRNAs need to be identified and investigated to guide the clinical prognosis or therapy for breast cancer. METHOD: The copy number variations (CNVs) of MIR3613 from Cancer Genome Atlas (TCGA) or Cancer Cell Line Encyclopedia (CCLE) were analyzed, and its correlation with breast cancer subtypes or prognosis was investigated. The expression level of miR-3613-3p in tumor tissues or serum of breast cancer patients was detected using in situ hybridization and qPCR. Gain-of-function studies were performed to determine the regulatory role of miR-3613-3p on proliferation, apoptosis, and tumor sphere formation of human breast cancer cells MDA-MB-231 or MCF-7. The effects of miR-3613-3p on tumor growth or metastasis in an immunocompromised mouse model of MDA-MB-231-luciferase were explored by intratumor injection of miR-3613-3p analogue. The target genes, interactive lncRNAs, and related signaling pathways of miR-3613-3p were identified by bioinformatic prediction and 3'-UTR assays. RESULTS: We found that MIR3613 was frequently deleted in breast cancer genome and its deletion was correlated with the molecular typing, and an unfavorable prognosis in estrogen receptor-positive patients. MiR-3613-3p level was also dramatically lower in tumor tissues or serum of breast cancer patients. Gain-of-function studies revealed that miR-3613-3p could suppress proliferation and sphere formation and promote apoptosis in vitro and impeded tumor growth and metastasis in vivo. Additionally, miR-3613-3p might regulate cell cycle by targeting SMS, PAFAH1B2, or PDK3 to restrain tumor progression. CONCLUSION: Our findings indicate a suppressive role of miR-3613-3p in breast cancer progression, which may provide an innovative marker or treatment for breast cancer patients.

CCL16 maintains stem cell-like properties in breast cancer by activating CCR2/GSK3ß/ß-catenin/OCT4 axis.

Rationale: Considerable evidence suggests that breast cancer metastasis and recurrence occur due to emergence of cancer stem cells (CSCs). In our previous study, we designed a high-throughput siRNA screening platform that identifies inflammation genes involved in the regulation of cancer cell stemness. We reported that CCL16 protein decreases OCT4 expression and reduces the ALDH+ subpopulation. However, the mechanism by which CCL16 maintains stem cell-like properties remains unclear. Methods: Tissue microarrays were used to evaluate CCL16 expression. Cancer stemness assays were performed in CCL16 knockdown and overexpressing cells in vitro and in a xenograft model in vivo. Human phosphokinase array, immunofluorescence and chromatin immunoprecipitation assays were performed to explore the underlying mechanism. Results: We report that CCL16 was overexpressed in breast tumors and significantly correlated with clinical progression. We found that silencing CCL16 in MDA-MB-231 and BT549 cells diminished CSC properties including ALDH+ subpopulation, side population, chemo-resistance, and sphere formation. Furthermore, mice bearing CCL16-silenced MDA-MB-231 xenografts had lower tumorigenic frequency and developed smaller tumors. Exploration of the underlying mechanism found that CCL16 selects CCR2 to activate p-AKT/GSK3ß signaling and facilitate ß-catenin nuclear translocation. Further, CCL16 binds to the OCT4 promoter and promotes OCT4 expression. In addition, shRNAs targeting CCR2 and XAV939 targeting ß-catenin abolished CCL16-mediated cancer stemness. Upstream, IL10 mediates STAT3 activation, which binds to the CCL16 promoter and enhances its expression. The STAT3-targeted inhibitor Stattic suppressed CCL16 expression in vitro and restrained tumor progression in vivo. Conclusions: We identified a potential CSC regulator and suggest a novel mechanism for how CCL16 governs cancer cell stemness. We propose that CCL16 could be an effective target for breast cancer therapy.

Mouse 4T1 Breast Cancer Cell-Derived Exosomes Induce Proinflammatory Cytokine Production in Macrophages via miR-183.

Tumor-associated macrophages (TAMs) play a critical role in the tumor inflammatory microenvironment and facilitate tumor growth and metastasis. Most types of tumors aberrantly express microRNAs (miRNAs), which can be transferred between cells by exosomes and can regulate gene expression in recipient cells, but it remains unclear whether tumor-derived miRNAs are transferred by exosomes and regulate the TAM phenotype. We report that mouse 4T1 breast cancer cell-derived exosomes enhanced TAM expression of IL-1ß, IL-6, and TNF-α and that inhibition of 4T1-cell exosome secretion through short hairpin RNA-mediated Rab27a/b depletion repressed tumor growth and metastasis and markedly downregulated IL-1ß, IL-6, and TNF-α in a 4T1 breast tumor model. Furthermore, miRNA expression profiling revealed that three miRNAs (miR-100-5p, miR-183-5p, and miR-125b-1-3p) were considerably more abundant in 4T1 cell exosomes than in mouse bone marrow-derived macrophages, indicating potential exosome-mediated transfer of the miRNAs, and, notably, miR-183-5p was found to be transferred from 4T1 cells to macrophages through exosomes. Moreover, PPP2CA was verified as an miR-183-5p target gene, and PPP2CA downregulation enhanced NF-κB signaling and promoted macrophage expression of IL-1ß, IL-6, and TNF-α. Lastly, when miR-183-5p was downregulated in exosomes through miR-183-5p sponge expression in 4T1 cells, these 4T1-derived exosomes triggered diminished p65 phosphorylation and IL-1ß, IL-6, and TNF-α secretion, and the miRNA downregulation also led to repression of tumor growth and metastasis in the 4T1 breast tumor model in vivo. Thus, miR-183-5p expressed in tumor cells was transferred to macrophages by exosomes and promoted the secretion of proinflammatory cytokines by inhibiting PPP2CA expression, which contributed to tumor progression in a breast cancer model.

MicroRNAs in tumor immunity: functional regulation in tumor-associated macrophages.

Tumor-associated macrophages (TAMs) are the most abundant immune cells in the tumor microenvironment (TME) and are critical for cancer initiation and progression. MicroRNAs (miRNAs) could notably influence the phenotype of TAMs through various targets and signal pathways during cancer progression due to their post-transcriptional regulation. In this review, we discuss mainly the regulatory function of miRNAs on macrophage differentiation, functional polarization, and cellular crosstalk. Firstly, during the generation process, miRNAs take part in the differentiation from myeloid cells to mature macrophages, and this maturation process directly influences their recruitment into the TME, attracted by tumor cells. Secondly, macrophages in the TME can be either tumor-promoting or tumor-suppressing, depending on their functional polarization. Large numbers of miRNAs can influence the polarization of macrophages, which is crucial for tumor progression, including tumor cell invasion, intravasation, extravasation, and premetastatic site formation. Thirdly, crosstalk between tumor cells and macrophages is essential for TME formation and tumor progression, and miRNAs can be the mediator of communication in different forms, especially when encapsulated in microvesicles or exosomes. We also assess the potential value of certain macrophage-related miRNAs (MRMs) as diagnostic and prognostic markers, and discuss the possible development of MRM-based therapies.

Cancer Stem Cells of Diffuse Large B Cell Lymphoma Are Not Enriched in the CD45+CD19- cells but in the ALDHhigh Cells.

Although the existence of cancer stem cells (CSCs) has been suggested in diffuse large B cell lymphoma (DLBCL), there is still no definitive marker. CD45+CD19- has been regarded as a potential marker of CSCs in mantle cell lymphoma (MCL). So, we explored the role of CD45+CD19- in DLBCL. However, both CD45+CD19- cells and CD45+CD19+ cells did not generate tumors until more than 100,000 cells were inoculated in NOD/SCID mice, even CD45+CD19+ cells generated more and larger tumors, as well as the soft agar colony formation in vitro; The aldehyde dehydrogenase (ALDH) activity was also identified in this study. Only 1,500 ALDHhigh cells were enough to generate tumors in mice while the same number of ALDH- cells were not. Moreover, both groups formed tumors when more cells were inoculated, but ALDHhigh cells formed more and larger tumors. The similar result was obtained in vitro clonogenicity experiments. OCT4, SOX2, Nanog, and ABCG2 genes did not show any difference in CD45+CD19+, CD45+CD19-, ALDHhigh and ALDH- cells. Taken together, CSCs are not enriched in the CD45+CD19- cells but in the ALDHhigh cells in DLBCL cell lines.

Phosphodiesterase 3A Represents a Therapeutic Target that Drives Stem Cell-like Property and Metastasis in Breast Cancer.

Considerable evidence suggests that as breast cancer progresses, genetic and epigenetic mechanisms contribute to the emergence of self-renewing cells (CSC), which may also arise as a consequence of metastasis. Although the molecular pathways that trigger stemness and metastasis are known, key molecular and mechanistic gaps in our understanding of these processes remain unclear. Here, we first screened the inflammation-associated stemness gene phosphodiesterase 3A (PDE3A) using a medium-throughput siRNA library, which was overexpressed in breast tumors and significantly correlated with clinical progression. PDE3A induced the inflammatory nuclear factor NFκB signaling pathway by suppressing cAMP/PKA, which promotes the expression of the stem cell marker OCT4. In addition, PDE3A also promoted the translocation of CCDC88A from the cytoplasm to nuclei, thereby boosting the invasion-metastasis cascade in breast cancer. Most importantly, the PDE3A-selective inhibitor cilostazol dramatically suppressed breast tumor growth and reduced metastasis to the lungs in xenograft breast cancer models, with minimum toxicity. Taken together, we show that PDE3A could predispose patients with breast cancer to metastases by acting as a mediator of cancer stemness. PDE3A is a potential therapeutic target for advanced breast cancer.

TGIF2 promotes the progression of lung adenocarcinoma by bridging EGFR/RAS/ERK signaling to cancer cell stemness.

TGF-ß-induced factor homeobox 2 (TGIF2) is a transcription regulator that plays essential roles in the regulation of development and cell fate decisions. Aberrant expression of TGIF family proteins has been observed in several cancers, including ovarian, esophageal, and colorectal cancers. Here, we report that TGIF2 mediates the EGFR-RAS-ERK signaling pathway to enhance the stemness of lung adenocarcinoma (LUAD) cells and, therefore, promote the progression and metastasis of LUAD. We found that high TGIF2 expression was closely correlated with tumor growth, lymph node metastasis, and survival of patients with LUAD. Mice bearing TGIF2-silenced H1299 xenografts developed smaller tumors and fewer lung metastases. Importantly, silencing TGIF2 decreased the cancer stem cell (CSC)-like properties in A549 and H1299 cells. Furthermore, we identified that TGIF2 binding to the OCT4 promoter promotes its expression. In both LUAD cells and in vivo LUAD mouse models, we revealed that EGFR-RAS-ERK signaling phosphorylated TGIF2 and increased its stability, which was important for TGIF2-promoted LUAD stemness since phosphorylation-deficient TGIF2 mutants lost these functions. Thus, our study revealed that an important factor, TGIF2, bridges EGFR signaling to the CSC characteristics of LUAD cells, which can be utilized as an effective target for LUAD therapy.

Targeting LIN28B reprograms tumor glucose metabolism and acidic microenvironment to suppress cancer stemness and metastasis.

The altered metabolism and acidic microenvironment plays an important role in promoting tumor malignant characteristics. A small population of cancer stem cells (CSCs) were considered as a therapy target to reserve tumor relapse, resistance, and metastasis. However, the molecular mechanism that regulates CSCs metabolism remains poorly understood. In this study, we demonstrate a fundamental role of stemness gene LIN28B in maintaining CSCs glycolysis metabolism. Using LIN28B-expressing cancer cell lines, we found that the rate of extracellular acidification, glucose uptake, and lactate secretion are all suppressed by LIN28B knockdown in vitro and in vivo. Importantly, metabolic analyses reveal that CSCs have enhanced aerobic glycolysis metabolic characteristics and the glycolytic product lactate further promotes cancer associated stemness properties. LIN28B silencing suppresses MYC expression that further increases miR-34a-5p level. Furthermore, the glycolysis metabolism of human breast cancer cell line MDA-MB-231 is suppressed by either MYC siRNA or miR-34a-5p mimic. Clinically, high MYC and low miR-34a-5p level are correlated with high LIN28B expression and poor prognosis in human breast cancer patients. Notably, blocking LIN28B/MYC/miR-34a-5p signaling pathway by LIN28B-specific inhibitor causes dramatic inhibition of tumor growth and metastasis in immunodeficient orthotopic mouse models of human breast cancer cell MDA-MB-231. Taken together, our findings offer a preclinical investigation of targeting LIN28B to suppress CSCs glycolysis metabolism and tumor progression that may improve the therapeutic benefit for cancer patients.

Immunostimulatory Activities of CpG-Oligodeoxynucleotides in Teleosts: Toll-Like Receptors 9 and 21.

Toll-like receptors (TLRs) are pattern-recognition receptors that detect a wide variety of microbial pathogens for the initiation of host defense immunological responses. Thirteen TLRs have been identified in mammals, and teleosts contain 22 mammalian or non-mammalian TLRs. Of these, TLR9 and TLR21 are the cytosine-phosphate-guanosine-oligodeoxynucleotides (CpG-ODNs) recognition TLRs in teleosts. TLR9 is a mammalian TLR expressed in teleost but not in the avian species. TLR21 is a non-mammalian TLR expressed in both teleost and the avian species. Synthetic CpG-ODNs are potent immunostimulants that are being studied for their application against tumors, allergies, and infectious diseases, and as a vaccine adjuvant in humans. The immunostimulatory effects of CpG-ODNs as vaccine adjuvants and their antimicrobial function in domestic animals and teleosts are also being investigated. Most of our current knowledge about the molecular basis for the immunostimulatory activity of CpG-ODNs comes from earlier studies of the interaction between CpG-ODN and TLR9. More recent studies indicate that in addition to TLR9, TLR21 is another receptor for CpG-ODN recognition in teleosts to initiate immune responses. Whether these two receptors have differential functions in mediating the immunostimulatory activity of CpG-ODN in teleost has not been well-studied. Nevertheless, the existence of two recognition TLRs suggests that the molecular basis for the immunostimulatory activity of CpG-ODN in teleosts is different and more complex than in mammals. This article reviews the current knowledge of TLR9 and TLR21 activation by CpG-ODNs. The key points that need to be considered for CpG-ODNs as immunostimulants with maximum effectiveness in activation of immune responses in teleosts are discussed. This includes the structure/activity relationship of CpG-ODN activities for TLR9 and TLR21, the structure/functional relationship of these two TLRs, and differential expression levels and tissue distributions for these two TLRs.

Low mutation and neoantigen burden and fewer effector tumor infiltrating lymphocytes correlate with breast cancer metastasization to lymph nodes.

Lymph node metastasis is of major prognostic significance for breast cancer. Lymph node metastasis arises at a very early stage in some patients. Using the data downloaded from the TCGA database, we studied the differences between primary tumors with and without lymph node metastasis at the multi-omics level using bioinformatics approaches. Our study found that low mutation and neoantigen burdens correlated with lymph node metastazation of breast cancer. All three conserved domains in TP53 were mutated in lymph node-negative breast cancers, whereas only one domain was mutated in lymph node-positive samples. Mutations in microtubule-related proteins appear to help immune cells recognize tumors and inhibit their lymph node metastasis. Destroying microtubule-related proteins is a potential therapeutic strategy to inhibit lymph node metastasis of breast cancer. As the neoantigens specifically present in lymph node-positive breast cancers, MAPK10, BC9L, TRIM65, CD93, KITLG, CNPPD1, CPED1, CCDC146, TMEM185A, INO80D, and PSMD11 are potential targets for vaccine design. In the tumor microenvironment, reduced numbers of effector immune cells, especially activated memory CD4+ T cells and activated mast cells, facilitate breast cancer metastasis to the lymph nodes. According to transcriptome data, lymph node metastasis was mostly driven by gene mutation rather than by gene expression. Although differential gene expression analysis was based on lymph node metastasis status, many genes were shown to be differentially expressed based on estrogen receptor status.

miR-100 maintains phenotype of tumor-associated macrophages by targeting mTOR to promote tumor metastasis via Stat5a/IL-1ra pathway in mouse breast cancer.

Tumor-associated macrophages (TAMs), the main part of immune cells in tumor microenvironment (TME), play a potent role in promoting tumorigenesis through mechanisms such as stimulating angiogenesis, enhancing tumor migration and suppressing antitumor immunity. MicroRNAs (miRNAs) are considered as crucial regulators in multiple biological processes. The relationship between miRNAs and macrophages function has been extensively reported, but the roles that miRNAs play in regulating TAMs phenotype remain unclear. In this study, we screened highly expressed microRNAs in TAMs, and first identified that miR-100 represented a TAMs-high expression pattern and maintained TAMs phenotype by targeting mTOR signaling pathway. Moreover, miR-100 expression level in TAMs was positively related to IL-1ra secretion, a traditional immune-suppressive cytokine, which was determined to promote tumor cells stemness via stimulating Hedgehog pathway. Mechanism study suggested that mTOR/Stat5a pathway was involved in IL-1ra transcriptional regulation process mediated by miR-100. More importantly, tumor metastasis and invasion capacity were significantly decreased in a 4T1 mouse breast cancer model injected intratumorally with miR-100 antagomir, and combination therapy with cisplatin showed much better benefit. In this study, we confirm that highly expressed miR-100 maintains the phenotype of TAMs and promotes tumor metastasis via enhancing IL-1ra secretion. Interfering miR-100 expression of TAMs in mouse breast cancer model could inhibit TAMs pro-tumor function and reduce tumor metastasis, which suggests that miR-100 could serve as a potential therapy target to remodel tumor microenvironment in breast cancer.