Autoantibodies against Angiotensin-converting enzyme 2 and immune molecules are associated with COVID-19 disease severity

Increased inflammation caused by SARS-CoV-2 infection can lead to severe coronavirus disease 2019 (COVID-19) and long-term disease manifestations referred to as post-acute sequalae of COVID (PASC). The mechanisms of this variable long-term immune activation are poorly defined. Autoantibodies targeting immune factors such as cytokines, as well as the viral host cell receptor, angiotensin-converting enzyme 2 (ACE2), have been observed after SARS-CoV-2 infection. Autoantibodies to immune factors and ACE2 could interfere with normal immune regulation and lead to increased inflammation, severe COVID-19, and long-term complications. Here, we deeply pro led the features of ACE2, cytokine, and chemokine autoantibodies in samples from patients recovering from severe COVID-19. We identified epitopes in the catalytic domain of ACE2 targeted by these antibodies, that could inhibit ACE2 function. Levels of autoantibodies targeting ACE2 and other immune factors could serve as determinants of COVID-19 disease severity, and represent a natural immunoregulatory mechanism in response to viral infection.

Identification of conserved coronavirus epitopes targeted by antibodies after SARS-CoV-2 infection or vaccination

SARS-CoV-2 is a novel betacoronavirus that causes coronavirus disease 2019 and has resulted in millions of deaths worldwide. Novel coronavirus infections in humans have steadily become more common. Understanding antibody responses to SARS-CoV-2, and identifying conserved, cross-reactive epitopes among coronavirus strains could inform the design of vaccines and therapeutics with broad application. Here, we determined that individuals with previous SARS-CoV-2 infection or vaccinated with the Pfizer-BioNTech BNT162b2 vaccine produced antibody responses that cross-reacted with related betacoronaviruses. Moreover, we designed a peptide-conjugate vaccine with a conserved SARS-CoV-2 S2 spike epitope, immunized mice and determined cross-reactive antibody binding to SARS-CoV-2 and other related coronaviruses. This conserved spike epitope also shared sequence homology to proteins in commensal gut microbiota and antibodies targeting this region reacted with proteins in human fecal protein extracts. This indicated that the composition of the gut microbiota could prime immune responses in humans. Thus, SARS-CoV-2 conserved epitopes elicited cross-reactive immune responses to both related coronaviruses and host bacteria that could serve as future targets for broad coronavirus therapeutics and vaccines.

This work was supported through internal institutional funds from Children’s Mercy Research Institute and Children’s Mercy Kansas City.

Humoral immune responses during SARS-CoV-2 mRNA vaccine administration in seropositive and seronegative individuals

BACKGROUND

The global pandemic of coronavirus disease 2019 (COVID-19) is caused by infection with the SARS-CoV-2 virus. Currently, there are three approved vaccines against SARS-CoV-2 in the USA, including two based on messenger RNA (mRNA) technology that has demonstrated high vaccine efficacy. We sought to characterize humoral immune responses, at high resolution, during immunization with the BNT162b2 (Pfizer-BioNTech) vaccine in individuals with or without prior history of natural SARS-CoV-2 infection.

METHODS

We determined antibody responses after each dose of the BNT162b2 SARS-CoV-2 vaccine in individuals who had no prior history of SARS-CoV-2 infection (seronegative) and individuals that had previous viral infection 30-60 days prior to first vaccination (seropositive). To do this, we used both an antibody isotype-specific multiplexed bead-based binding assays targeting multiple SARS-CoV-2 viral protein antigens and an assay that identified potential SARS-CoV-2 neutralizing antibody levels. Moreover, we mapped antibody epitope specificity after immunization using SARS-CoV-2 spike protein peptide arrays.

RESULTS

Antibody levels were significantly higher after a single dose in seropositive individuals compared to seronegative individuals and were comparable to levels observed in seronegative individuals after two doses. While IgG was boosted by vaccination for both seronegative and seropositive individuals, only seronegative individuals had increased IgA or IgM antibody titers after primary immunization. We identified immunodominant peptides targeted on both SARS-CoV-2 spike S1 and S2 subunits after vaccination.

CONCLUSION

These findings demonstrated the antibody responses to SARS-CoV-2 immunization in seropositive and seronegative individuals and provide support for the concept of using prior infection history as a guide for the consideration of future vaccination regimens. Moreover, we identified key epitopes on the SARS-CoV-2 spike protein that are targeted by antibodies after vaccination that could guide future vaccine and immune correlate development.

Abstract 4888: Disrupting MUC1/IFITM1 crosstalk reverses the aggressive phenotype of aromatase inhibitor-resistant breast cancer

Breast cancer is the most commonly diagnosed and second most lethal cancer among women, affecting over 252,000 women in 2017. The ER+/PR+ subtype of breast cancer is the most frequently diagnosed, representing approximately 70% of all cases. Estrogen depletion through aromatase inhibitors (AIs) is the standard of care to cause tumor regression in the ER+ subtype. Our research focuses on targeting the AI-resistant tumors that develop in 30% of women. The human oncoprotein, mucin 1 (MUC1), drives tumorigenesis in breast carcinomas promoting the epithelial-mesenchymal transition, epigenetic reprogramming, and evasion of the immune response. MUC1 interacts with the STAT proteins, via the JAK/STAT signaling pathway, and stimulates transcription of interferon-stimulated genes (ISGs) including IFITM1. Our laboratory has shown that IFITM1 is overexpressed in AI-resistant breast cancer cells and AI-resistant tumors and promotes an aggressive phenotype. In this study, we demonstrate that MUC1 is differentially regulated in endocrine-sensitive (MCF-7 and T-47D) compared to AI-resistant (MCF-7:5C) cells and that it plays a critical role in enhancing IFITM1 expression in the resistant cells. Analysis of a tumor microarray of 94 ER+ human breast tumors indicated that co-expression of both MUC1 and IFITM1 correlated with poor recurrence-free survival, poor overall survival, and AI resistance. To investigate how disruption of the MUC1/IFITM1 crosstalk effects cell survival and proliferation, we used an AI-resistant cell line (MCF-7:5C) that overexpresses MUC1, P-STAT1, and IFITM1. We genetically manipulated breast cancer cells by knocking down the levels of MUC1 with siRNA and observed lowered expression of IFITM1 at the mRNA and protein level and reduced IFITM1 promoter activation. Additionally, knockdown of MUC1 and IFITM1 levels with siRNA induced cell death in AI-resistant cells (MCF-7:5C). We verified this effect with the pharmacologic inhibitors GO-201 (a MUC1 inhibitor) and ruxolitinib (a JAK/STAT inhibitor) to interfere with the MUC1/IFITM1 crosstalk in vitro. Both agents significantly reduced cell proliferation in resistant cells (MCF-7:5C) but not in estrogen-sensitive cell lines (MCF-7 and T-47D). Co-IP confirmed the physical interaction between MUC1 and STAT1/2 and ruxolitinib treatment blocked this interaction by inhibiting STAT phosphorylation in both AI-resistant and -sensitive cells. In vivo studies using ruxolitinib significantly reduced tumor size in NSG mice and decreased expression of MUC1, P-STAT1, and IFITM1. The research discussed here highlights a novel mechanism by which breast cancer cells develop AI resistance and suggests that disrupting MUC1/IFITM1 crosstalk might be therapeutically beneficial to patients with AI-resistant disease.

Citation Format: Taylor E. Escher, Eric Geanes, Asona Lui, Joan Lewis-Wambi. Disrupting MUC1/IFITM1 crosstalk reverses the aggressive phenotype of aromatase inhibitor-resistant breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4888.

Abstract 1899: Targeting interferon induced transmembrane protein-1 (IFITM1) attenuates the aggressive phenotype of inflammatory breast cancer

Inflammatory breast cancer (IBC) is the most aggressive and lethal subtype of breast cancer, with triple-negative IBC being the most difficult to treat IBC subgroup. Improved understanding of mechanisms that lead to aggressiveness of triple-negative IBC could provide a basis for therapeutic targets. Our laboratory has identified a novel interferon (IFN)-α signaling target called interferon induced transmembrane protein-1 (IFITM1), which we hypothesize to promote the aggressive phenotype of triple-negative IBC. CRISPR/CAS9 was utilized to silence IFITM1 in SUM149 TN-IBC cells. In vitro, we found that knockout of IFITM1 increased in colony and mammosphere formation, inhibited migration as observed by the wound healing assay, and enhanced sensitivity to mainstay chemotherapeutic agents (taxol and doxorubicin) analyzed by flow cytometry, MTT and Tunel staining. Western blot analysis shows a decrease in c-Src and p-Src, vimentin, and CD44v expression, which are important regulators of migration and invasion. RNA sequencing analysis further indicates that knocking down IFITM1 promotes overall downregulation of pathways including breast cancer invasion, supporting our in vitro findings. In vivo, IFITM1-CRISPR/KD SUM149 cells were injected into the mammary fat pads of immunosuppressed female NSG mice to assess tumor growth. We found that mice injected with IFITM1-CRISPR/KD SUM149 cells showed significantly reduced tumor growth compared to mice injected with CRISPR/control SUM149 cells, which was observed at all time points examined. We used the mammary intraductal (MIND) method to assess tumor invasion in vivo. IFITM1-CRISPR/KD SUM149 cells showed decreased invasion outside of the mammary duct and decreased vimentin expression, further corroborating our in vitro data. Lastly, through tail vein injections to model metastasis, 33% of mice injected with SUM149 wildtype cells developed liver metastasis while 0% of mice injected with IFITM1-CRISPR/KD SUM149 mice developed liver metastasis. We have ongoing studies to further understand the mechanism by which IFITM1 regulates cellular migration, as well as invasion and angiogenesis in triple-negative IBC, which are all shown to be downregulated through RNA sequencing analysis. Overall, these findings indicate that IFITM1 may be driving the aggressiveness of triple-negative IBC and they suggest that IFITM1 may serve as a potential therapeutic target.

Citation Format: Olivia Provance, Eric Geanes, Joshua Ogony, Asona Lui, Eric Young, Sumedha Gunewardena, Joan Lewis-Wambi. Targeting interferon induced transmembrane protein-1 (IFITM1) attenuates the aggressive phenotype of inflammatory breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1899.

Abstract 3848: The clinical relevance of targeting IFITM1 in three distinct subtypes of aggressive breast cancer

Breast cancer can be separated into estrogen receptor/ progesterone receptor positive (ER+/PR+), Her2/neu positive (HER2+), and triple negative (ER-/PR-/HER2-) subtypes. Additionally, breast cancer may manifest clinically as either non-inflammatory or inflammatory disease. Inflammatory breast cancer is a highly lethal subtype of breast carcinoma that may express any of the three aforementioned receptors. Our laboratory has found that a novel marker, interferon-induced transmembrane protein 1 (IFITM1), is overexpressed in multiple subtypes of breast cancer and its overexpression is associated with poor overall survival as well as resistance to endocrine therapy, chemotherapy, and radiation. IFITM1 is a type 1 interferon (IFN) stimulated gene that is not expressed in normal breast tissue, and is only induced upon IFN exposure. In this study, we conducted immunohistochemical staining for IFITM1 in 94 ER+ human breast tumor samples and discovered that high IFITM1 expression was associated with increased clinical stage and resistance to endocrine therapy. Elevated expression of IFITM1 was also detected in human triple negative breast cancer (TNBC) samples as compared to normal breast tissue. Notably, this overexpression was most pronounced in TNBC tumors from African American (AA) patients. We screened a panel of nine cell lines that represent all major subtypes of breast cancer and found IFITM1 overexpression in ER+ aromatase inhibitor-resistant MCF-7:5C, AA-derived triple negative MDA-MB-468 and MDA-MB-157, and triple negative inflammatory SUM149 cells. We used inducible shRNA and CRSPR/Cas9 respectively, to investigate the effect of IFITM1 knockdown on MCF-7:5C and SUM149 xenograft tumors using two in vivo breast cancer models. The orthotopic (mammary fat pad) model evaluated tumor proliferation, and the mammary intraductal (MIND) model assessed tumor cell invasion out of the milk duct. We found that loss of IFITM1 in MCF-7:5C and SUM149 cells significantly inhibited their ability to form tumors in vivo and it completely blocked their ability to invade out of the milk duct. Additional studies indicated that hyper-activated JAK/STAT signaling was responsible for driving IFITM1 expression in MCF-7:5C, MDA-MB-468, and SUM149 cells. Furthermore, we demonstrated that JAK/STAT activation can be targeted in vivo with the FDA approved JAK inhibitor ruxolitinib (Jakafi™). Oral treatment of mice with 50 μg/g bodyweight ruxolitinib reduced IFITM1 expression and inhibited the growth of both MCF-7:5C and MDA-MB-468 tumors by loss of STAT1/2 phosphorylation. The overexpression of IFITM1 in three distinct breast cancer subtypes indicates that IFITM1 may be a targetable marker of aggressive disease in general and may open the door for novel therapies of treatment-refractory breast cancer.

Citation Format: Asona Lui, Joshua Ogony, Jordan Marquess, Eric Geanes, William Jewell, Ikbale El Ayachi, Gustav Miranda-Carboni, Ossama Tawfik, Joan Lewis-Wambi. The clinical relevance of targeting IFITM1 in three distinct subtypes of aggressive breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3848. doi:10.1158/1538-7445.AM2017-3848