Awesome! Autologous iPSC-based vaccines elicit anti-tumor responses in vivo (自体iPSC可作为抗肿瘤疫苗)

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Article Link

Titlehttps://www.sciencedirect.com/science/article/pii/S193459091830016X

1. Background

Cancer cells and embryonic tissues share some cellular and molecular properties. Pluripotent stem cells (iPSCs) express tumor-associated antigens, suggesting iPSCs may be harnessed to stimulate the immune response, then elicit anti-tumor response.

2. Knowledge accumulation

1. Th17 cells: Th17 cells are kind of pro-inflammatory T helper cells, which involve in adaptive immunity by response to pathogens. They also interact with B cells in response to pathogens. It's the mediator of type 3 allergic reaction.

2. Myeloid-derived suppressor cells (MDSCs): MDSCs is the precursor of dendritic cell (DCs), macrophage and granulocyte, which can suppress the response ability of immune cells.

3. The mice MDSDs' phenotype is CD11b+Gr-1+ and it can be divided into two subtypes, including CD11b+Ly6C-Ly6G+ and CD11b+Ly6C+Ly6G-. While human MSCDs are defined as Lin-HLA-DR-CD33+ or CD11b+CD14-CD33+, which suppress immunity responses by produce Arg-1, iNOS(NOS2) and ROS.

4. CpG sites: CpG sites also named CG sites. CpG is shorthand for 5'-cytosine-phosphate-guanine-3', which can be considered as a immunity stimulus.

5. CD4+ T cells: CD4+ T cell aid antigen-presenting cells (APC) to stimulate immunity responses via a combination of cell-to-cell interactions (e.g. CD40 and CD40L) and cytokines.

6. CD8+ T cells: CD8+ T cells (cytotoxic T cells, T-killer cell or killer T cell) is a lymphocyte that can kill cancer cells, infected cells with viruses, or other damaged cells.

7. Tumor-infiltrating lymphocytes (TILs): are white blood cells that have left the bloodstream and migrated toward tumor, including T and B cells.

8. Major histocompatibility complex (MHC): MHC is a kind of cell surface protein that help acquired immune system to recognize foreign molecules.

9. Antigen-presenting cells (APCs): APCs cells are the essential component of presenting antigens by display antigen complex via their surface MHCs.

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3. Material and methods

1. Animal model: FVB mice (白化病，同系交配小鼠);

   C57BL/6: It is the most widely used "genetic background" for genetically modified mice for use as models of human disease (常用于构造基因修饰小鼠).

   CBA/J: It’s a general-purpose strain and it is homozygous for the retinal degeneration allele Pde6brd1. is used in granulomatous experimental autoimmune thyroiditis (G-EAT) studies (常用于免疫相关研究).

2. The breast cancer line DB7: It was derived from FVB mice and is a non-metastatic cell line (小鼠乳腺癌细胞系--无转移能力).

   B16F0 melanoma cell line: B16F0 cell line is syngeneic to C57BL/6 mice, which has low-grade lymphoid metastatic potential to the lungs (小鼠高肺转移能力黑色素瘤细胞系).

   AC29 mesothelioma cancer line

3. CpG + iPSC vaccine preparation and immunization: The murine iPSCs were irradiated before injection.

4. Mixed lymphocyte reaction (MLR): Spleens were isolated, minced and divided into pellet and plated in plates, then incubated with DB7 tumor lysate. The cytokine analysis were performed by ELISArray kit.

5. Teratoma formation: The teratoma is due to the iPSCs.

4. Results

1. Human and Murine iPSCs Express Tumor-Specific and Tumor-Associated Antigens

   RNA sequencing results suggests that human iPSCs have overlap gene expression with human embryonic stem cells (hESCs) and the cancer tissues. Suggesting that using iPSCs to prime the host immunity response may also stimulate the immunity against unknown tumor-specific antigens (TSAs) and tumor-associated antigens (TAAs). 因为iPSCs与hESCs及肿瘤组织具有重叠的基因表达，尤其是肿瘤特异性的表面抗原。因此可用iPSC诱导机体免疫应答，从而杀伤与iPSCs具有相同表明抗原的肿瘤细胞。

2. iPSC-Vaccine-Primed Mice Mount Strong B and T Cell Responses against Breast Cancer In Vitro and In Vivo

   (1) When primed FVB mice with iPSCs or C+I for 4 weeks can arise the strongest in vitro T cell responses to DB7 tumor lysate.

   (2) The progression of DB7 tumor in vivo can be suppressed by 4 weeks vaccination.

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3. **C+I Vaccination Provides Breast Cancer and Melanoma Immunity by Upregulating Antigen Presentation and T-Helper/Cytotoxic T Cell Activity, which is the results of shared Shared Epitopes **

   (1) C+I vaccination stimulated immune response by increased effector/memory helper T cells (CD4+CD44+), effector/memory cytotoxic T cells (CD8+CD44+), APCs and decreased the percentages of regulatory T cells (CD4+CD25+FoxP3+). Furthermore, C+I-vaccinated FVB mice showed increased percentages of activated cytotoxic T cells (CD8+granzyme-B+) in spleens, mature antigen-presenting macrophage, CD4+CD44+ and CD8+CD44+ in draining lymph
   nodes (dLNs). 接种C+I后，小鼠脾脏辅助T细胞，杀伤T细胞及抗原呈递细胞数目上升，而负责免疫抑制的Treg数目下调，引流淋巴结中辅助T及杀伤T细胞数量均上调，表明C+I接种可诱发机体对iPSCs的免疫反应。

   (2) C+I vaccinated C57BL/6 mice showed suppression of the growth of melanoma.

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   (3) T cells isolated from C+I or vehicle-vaccinated mice were transferred to tumor-bearing orthotopic breast cancer mice. T cells from C+I have shown the suppression effect on tumor growth.

   以上结果表明，在C+I接种小鼠体内，由于C+I引起的免疫抵抗，使得肿瘤生长减缓。分离C+I接种小鼠的T细胞接种至肿瘤小鼠中，仍然起到抑制肿瘤生长的效果，进一步证实C+I疫苗通过诱导T淋巴细胞免疫反应，从而杀伤与iPSCs细胞具有相同表面抗原的肿瘤细胞。

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4. C+I Vaccination in a Mesothelioma Model Elicits a Pro-inflammatory Profile for Tumor-Infiltrating Lymphocytes; C+I Adjuvant Therapy after Tumor Resection Leads to Decreased Tumor Load in Resection Areas and dLNs.

在黑色素瘤小鼠模型上接种C+I疫苗可促进小鼠肿瘤浸润性淋巴细胞（TILs）的抗炎因子谱。即C+I疫苗--诱发小鼠TILs分泌大量促炎因子；同时，给予肿瘤切除术后小鼠接种C+I疫苗仍可通过诱导TILs免疫反应，从而抑制肿瘤复发并延长小鼠寿命。

5. Conclusion and discussion

conclusion: 具有与肿瘤细胞相同表面抗原的自体iPSCs，可作为具有特异性表面抗原肿瘤的预防及治疗性疫苗。

discussion: 1. iPSCs是具有多种分化能力的多功能干细胞，其基因组不仅与肿瘤细胞相似，还可与其他正常身体器官组织细胞基因组重叠，iPSCs对机体正常细胞尤其是造血细胞的影响还需要进一步研究；2. 正常细胞与肿瘤细胞表面抗原都非常复杂，尤其肿瘤耐药或转移后可能获得新的表型，并且肿瘤耐药、转移与复发常常是患者死亡的因素，因而可借鉴本文思路研究C+I疫苗在不同肿瘤阶段的作用。

Graphical Abstract

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