Susana del Toro-Arreola

B7-H6, an immunoligand for the natural killer cell activating receptor NKp30, reveals inhibitory effects on cell proliferation and migration, but not apoptosis, in cervical cancer derived-cell lines

AbstractBackgroundAlthough great progress has been made in treatment regimens, cervical cancer remains as one of the most common cancer in women worldwide. Studies focusing on molecules that regulate carcinogenesis may provide potential therapeutic strategies for cervical cancer. B7-H6, an activating immunoligand expressed by several tumor cells, is known to activate NK cell-mediated cytotoxicity once engaged with its natural receptor NKp30. However, the opposite, that is, the effects in the tumor cell triggered by B7-H6 after interacting with NKp30 has not yet been well explored.MethodsIn this study, we evaluated the surface expression of B7-H6 by flow cytometry. Later, we stimulated B7-H6 positive cervical cancer derived-cell lines (HeLa and SiHa) with recombinant soluble NKp30 (sNKp30) protein and evaluated biological effects using the impedance RTCA system for cell proliferation, the scratch method for cell migration, and flow cytometry for apoptosis. Cellular localization of B7-H6 was determined using confocal microscopy.ResultsNotably, we observed that the addition of sNKp30 to the cervical cancer cell lines decreased tumor cell proliferation and migration rate, but had no effect on apoptosis. We also found that B7-H6 is selectively maintained in tumor cell lines, and that efforts to sort and purify B7-H6 negative or positive cells were futile, as negative cells, when cultured, regained the expression of B7-H6 and B7-H6 positive cells, when sorted and cultivated, lost a percentage of B7-H6 expression.ConclusionsOur results suggest that B7-H6 has an important, as of yet undescribed, role in the biology of the cervical tumor cells themselves, suggesting that this protein might be a promising target for anti-tumor therapy in the future.

Positive staining of the immunoligand B7-H6 in abnormal/transformed keratinocytes consistently accompanies the progression of cervical cancer

Abstract Background B7-H6 has been revealed as an endogenous immunoligand expressed in a variety of tumors, but not expressed in healthy tissues. Heretofore, no studies have been reported describing B7-H6 in women with cervical cancer. To investigate this question, our present study was conducted. Results This retrospective study comprised a total of 62 paraffinized cervical biopsies, which were distributed in five groups: low-grade squamous intraepithelial lesions (LSIL), high-grade squamous intraepithelial lesions (HSIL), squamous cervical carcinoma (SCC), uterine cervical adenocarcinoma (UCAC), and a group of cervicitis (as a control for non-abnormal/non-transformed cells). Cervical sections were stained by immunohistochemistry to explore the expression of B7-H6, which was reported according to the immunoreactive score (IRS) system. We observed a complete lack of B7-H6 in LSIL abnormal epithelial cells. Interestingly, B7-H6 began to be seen in HSIL abnormal epithelial cells; more than half of this group had B7-H6 positive cells, with staining characterized by a cytoplasmic and membranous pattern. B7-H6 in the SCC group was also seen in the majority of the sections, showing the same cytoplasmic and membranous pattern. Strong evidence of B7-H6 was notably found in UCAC tumor columnar cells (in 100% of the specimens, also with cytoplasmic and membranous pattern). Moreover, consistent B7-H6 staining was observed in infiltrating plasma cells in all groups. Conclusions B7-H6 IRS positively correlated with disease stage in the development of cervical cancer; additionally, B7-H6 scores were found to be even higher in the more aggressive uterine cervical adenocarcinoma, suggesting a possible future therapeutic target for this cancer type.

Immune checkpoint expression on peripheral cytotoxic lymphocytes in cervical cancer patients: moving beyond the PD-1/PD-L1 axis

SummaryImmune checkpoint therapy to reverse natural killer (NK) and T cell exhaustion has emerged as a promising treatment in various cancers. While anti-programmed cell death 1 (PD-1) pembrolizumab has recently gained Food and Drug Administration (FDA) approval for use in recurrent or metastatic cervical cancer, other checkpoint molecules, such as T cell immunoreceptor with immunoglobulin (Ig) and immunoreceptor tyrosine-based inhibition motif (ITIM) domains (TIGIT) and T cell immunoglobulin and mucin-domain containing-3 (Tim-3), have yet to be fully explored in this disease. We report expression of TIGIT, Tim-3 and PD-1 on subsets of peripheral blood NK (CD56dim/negCD16bright/dim/neg and CD56brightCD16dim/neg) and T cells. The percentages of these cells were increased in women with cervical cancer and pre-malignant lesions. PD-1+ NK and T cells were likely to co-express TIGIT and/or Tim-3. These cells, with an apparently ‘exhausted’ phenotype, were augmented in patients. A subset of cells were also natural killer group 2 member D (NKG2D)- and DNAX accessory molecule 1 (DNAM-1)-positive. PD-1int and PD-1high T cells were notably increased in cervical cancer. Soluble programmed cell death ligand 1 (PD-L1) was higher in cancer patient blood versus healthy donors and we observed a positive correlation between sPD-L1 and PD-1+ T cells in women with low-grade lesions. Within the cancer group, there were no significant correlations between sPD-L1 levels and cervical cancer stage. However, when comparing cancer versus healthy donors, we observed an inverse association between sPD-L1 and total T cells and a correlation between sPD-L1 and CD56dim NK cells. Our results may show an overview of the immune response towards pre-cancerous lesions and cervical cancer, perhaps giving an early clue as to whom to administer blocking therapies. The increase of multiple checkpoint markers may aid in identifying patients uniquely responsive to combined antibody therapies.

Cataloging circulating CD3+CD56+ NKT-like cells through a series of stimulating (NKG2D and DNAM-1) and inhibitory (PD-1, TIGIT, and Tim-3) immune checkpoint receptors in women diagnosed with precancerous cervical lesions or invasive cervical carcinoma

Persistent human papillomavirus infection is associated with the development of premalignant lesions that can eventually lead to cervical cancer. In this study, we evaluated the expression of activating (NKG2D, DNAM-1) and inhibitory immune checkpoints receptors (PD-1, TIGIT, and Tim-3) in peripheral blood NKT-like (CD3

Beyond Canonical Immune Checkpoints: Overexpression of TNFRSF Members 4‐1BB and OX‐40 Marks T Cells Exhibiting Phenotypic Features of Exhaustion in Cervical Carcinoma

ABSTRACTT cells are pivotal in combating cancer; however, they can become exhausted during tumour progression, losing their cytotoxic capacity and upregulating inhibitory receptors including PD‐1 and TIGIT. While checkpoint blockade has emerged as a potent treatment option for numerous cancers, patient selection, long‐term efficacy, and adverse effects still remain an issue. For these reasons, it is important to investigate other pathways that might lead to selective reactivation of the immune system. Co‐stimulatory TNFRSF receptors, including 4‐1BB and OX‐40, have emerged as promising targets for reactivating exhausted T cells. However, their expression on exhausted peripheral and tumour‐infiltrating lymphocytes (TILs) is not well characterised, particularly in cervical cancer (CC), which remains the leading cause of gynaecological cancer mortality in low‐ and middle‐income countries. To investigate the expression of these receptors, PBMCs were collected from CC patients and healthy donors, along with TILs from tumour biopsies, and analysed using multiparametric flow cytometry. Our findings revealed an increased population of phenotypically exhausted (PD‐1+TIGIT+) CD4+ and CD8+ T cells in TILs, and, to a lesser extent, in peripheral blood and from CC patients. These exhausted T cell subsets exhibited selective overexpression of 4‐1BB and OX‐40 compared to phenotypically non‐exhausted cells (PD‐1−TIGIT−). In TILs, 4‐1BB was overexpressed 12.7‐fold in CD8 cells with the exhausted phenotype, OX‐40 was overexpressed 3.3‐fold; in CD4 cells with the exhausted phenotype, the overexpression was 7.8× and 3.8× for 4‐1BB and OX‐40, respectively. CD8 and CD4 T cells that were PD‐1 + TIGIT+ 4‐1BB+ were 7.3× and 16× more likely to be found in the tumour versus peripheral blood. Additionally, subpopulations of PD‐1high T cells were significantly elevated in the tumour‐infiltrating T cells and TIGIT expression was positively associated with PD‐1 levels in peripheral patient CD8+ and CD4+ T cells, potentially indicating an advanced state of exhaustion. These findings suggest that TNFRSF members, especially 4‐1BB, may serve as potential immunotherapeutic targets for reinvigorating exhausted T cells in CC.