Servin-Garrido Roberto Raúl, Ilhuicatzi-Alvarado Damaris, Jiménez-Chávez Ángel de Jesús, Moreno-Fierros Leticia
Laboratorio de Inmunidad en Mucosas, Unidad de Investigación en Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios 1 Los Reyes Iztacala CP 54090, Tlalnepantla, Estado de México, México.
Breast Cancer (Auckl). 2022 Jan 5;16:11782234211065154. doi: 10.1177/11782234211065154. eCollection 2022.
The Cry1Ac protoxin from is a systemic and mucosal adjuvant, able to confer protective immunity in different infection murine models and induce both Th1 and TCD8+ cytotoxic lymphocyte responses, which are required to induce antitumor immunity. The Cry1Ac toxin, despite having not being characterized as an adjuvant, has also proved to be immunogenic and able to activate macrophages. Here, we investigated the potential antitumor adjuvant effect conferred by the Cry1Ac protoxin and Cry1Ac toxin in a triple negative breast cancer (TNBC) murine model. First, we evaluated the ability of Cry1Ac proteins to improve dendritic cell (DC) activation and cellular response through intraperitoneal (i.p.) coadministration with the 4T1 cellular lysate. Mice coadministered with the Cry1Ac protoxin showed an increase in the number and activation of CD11c+MHCII- and CD11c+MHCII+ in the peritoneal cavity and an increase in DC activation (CD11c+MHCII+) in the spleen. Cry1Ac protoxin increased the proliferation of TCD4+ and TCD8+ lymphocytes in the spleen and mesenteric lymph nodes (MLN), while the Cry1Ac toxin only increased the proliferation of TCD4+ and TCD8+ in the MLN. Remarkably, when tested in the in vivo TNBC mouse model, prophylactic immunizations with 4T1 lysates plus the Cry1Ac protoxin protected mice from developing tumors. The antitumor effect conferred by the Cry1Ac protoxin also increased specific cytotoxic T cell responses, and prevented the typical tumor-related decrease of T cells (TCD3+ and TCD4+) as well the increase of myeloid-derived suppressor cells (MDSC) in spleen. Also in the tumor microenvironment of mice coadministered twice with Cry1Ac protoxin immunological improvements were found such as reductions in immunosupressive populations (T regulatory lymphocytes and MDSC) along with increases in macrophages upregulating CD86. These results show a differential antitumor adjuvant capability of Cry1Ac proteins, highlighting the ability of Cry1Ac protoxin to enhance local and systemic tumor immunity in TNBC. Finally, using a therapeutic approach, we evaluated the coadministration of Cry1Ac protoxin with doxorubicin. A significant reduction in tumor volume and lung metastasis was found, with increased intratumoral levels of tumor necrosis factor-α and IL-6 with respect to the vehicle group, further supporting its antitumor applicability.
来自苏云金芽孢杆菌的Cry1Ac原毒素是一种全身性和黏膜佐剂，能够在不同的感染小鼠模型中赋予保护性免疫，并诱导Th1和TCD8 + 细胞毒性淋巴细胞反应，而这些反应是诱导抗肿瘤免疫所必需的。尽管Cry1Ac毒素尚未被鉴定为佐剂，但它也已被证明具有免疫原性并能够激活巨噬细胞。在此，我们研究了Cry1Ac原毒素和Cry1Ac毒素在三阴性乳腺癌（TNBC）小鼠模型中赋予的潜在抗肿瘤佐剂效应。首先，我们通过与4T1细胞裂解物腹腔内（i.p.）联合给药来评估Cry1Ac蛋白改善树突状细胞（DC）激活和细胞反应的能力。与Cry1Ac原毒素联合给药的小鼠腹腔内CD11c + MHCII - 和CD11c + MHCII + 的数量和激活增加，脾脏中DC激活（CD11c + MHCII +）增加。Cry1Ac原毒素增加了脾脏和肠系膜淋巴结（MLN）中TCD4 + 和TCD8 + 淋巴细胞的增殖，而Cry1Ac毒素仅增加了MLN中TCD4 + 和TCD8 + 的增殖。值得注意的是，在体内TNBC小鼠模型中进行测试时，用4T1裂解物加Cry1Ac原毒素进行预防性免疫可保护小鼠不发生肿瘤。Cry1Ac原毒素赋予的抗肿瘤作用还增加了特异性细胞毒性T细胞反应，并防止了脾脏中典型的肿瘤相关T细胞（TCD3 + 和TCD4 +）减少以及髓系来源抑制细胞（MDSC）增加。同样，在与Cry1Ac原毒素联合给药两次的小鼠的肿瘤微环境中也发现了免疫改善，例如免疫抑制群体（T调节淋巴细胞和MDSC）减少，同时上调CD86的巨噬细胞增加。这些结果显示了Cry1Ac蛋白不同的抗肿瘤佐剂能力，突出了Cry1Ac原毒素增强TNBC局部和全身肿瘤免疫的能力。最后，使用治疗方法，我们评估了Cry1Ac原毒素与阿霉素的联合给药。发现肿瘤体积和肺转移显著减少，相对于载体组，肿瘤内肿瘤坏死因子-α和IL-6水平增加，进一步支持了其抗肿瘤适用性。
