Generation of a Transgenic BALB/c Mouse Line With Selective Expression of Human Mesothelin in Thyroid Gland: Application in Mesothelin-targeted Immunotherapy

Anti-mesothelin immunotoxin induces mesothelioma eradication, anti-tumor immunity, and the development of tertiary lymphoid structures

LMB-100 is a recombinant immunotoxin composed of a Fab linked to a toxin. It kills cells expressing human mesothelin (hMSLN), which is highly expressed on the surface of mesothelioma and many other cancer cells. Clinically, we observed some patients had delayed responses to an anti-hMSLN immunotoxin treatment, suggesting the induction of anti-tumor immunity. We aimed to develop a mouse model to investigate whether immunotoxin alone can induce anti-tumor immunity and to study the mechanism of this immunity. An immunocompetent transgenic mouse was used to grow mouse mesothelioma AB1 cells expressing hMSLN in the peritoneal cavity. Mice were treated with LMB-100, and mice with complete responses (CRs) were rechallenged with tumor cells to determine whether anti-tumor immunity developed. Changes in gene expression profiles were evaluated by Nanostring, and changes in cytokines and chemokines were checked by protein arrays. The distribution of various immune cells was assessed by immunohistochemistry. Our results show that the mice with tumor reached CRs and developed anti-tumor immunity after LMB-100 treatment alone. The primary response requires CD8⁺ T cells, CD4⁺ T cells, and B cells. Transcriptional profiling shows that LMB-100 treatment reshapes the tumor immune microenvironment by upregulating chemotaxis signals. LMB-100 treatment upregulates genes associated with tertiary lymphoid structures (TLS) development and induces TLS formation in tumors. In sum, immunotoxin-mediated cell death induces anti-tumor immunity and the development of TLS, which provides insights into how immunotoxins cause tumor regressions.

Therapeutic Potential of Antibody-Drug Conjugate-Based Therapy in Head and Neck Cancer: A Systematic Review

BACKGROUND

Antibody-drug conjugates (ADCs) are designed to deliver potent cytotoxic agents into tumor tissues. During the last two decades, a plethora of ADCs have been successfully developed and used for several indications, including hematologic and solid tumors. In this work, we systematically reviewed the progress in ADC development for the treatment of HNC.

METHODS

This review was registered in PROSPERO database. A comprehensive search was conducted following PRISMA guidelines and using PubMed, Scopus and Web of Science database.

RESULTS

In total, 19 studies were included. Due to the significant heterogeneity of the outcome measures, meta-analysis was not performed, and data were summarized in tables. HNC results are poorly represented in the cohorts of completed clinical trials; published data are mostly focused on safety evaluation rather than efficacy of ADCs.

CONCLUSIONS

Although several novel agents against a wide range of different antigens were investigated, showing promising results at a preclinical level, most of the targets reported in this review are not specific for HNC; hence, the development of ADCs tailored for the HNC phenotype could open up new therapeutic perspectives. Moreover, the results from the present systematic review call attention to how limited is the application of current clinical trials in HNC.

Anti-cancer Immunotoxins, Challenges, and Approaches

The development of recombinant immunotoxins (RITs) as a novel therapeutic strategy has made a revolution in the treatment of cancer. RITs result from the fusion of antibodies to toxin proteins for targeting and eliminating cancerous cells by inhibiting protein synthesis. Despite indisputable outcomes of RITs regarding inhibition of multiple cancer types, high immunogenicity has been known as the main obstacle in the clinical use of RITs. Various strategies have been proposed to overcome these limitations, including immunosuppressive therapy, humanization of the antibody fragment moiety, generation of immunotoxins originated from endogenous human cytotoxic enzymes, and modification of the toxin moiety to escape the immune system. This paper is devoted to review recent advances in the design of immunotoxins with lower immunogenicity.

Oncolytic adenovirus targeting TGF-β enhances anti-tumor responses of mesothelin-targeted chimeric antigen receptor T cell therapy against breast cancer

Chimeric antigen receptor (CAR)-modified T cell therapy evokes only modest antitumor responses in solid tumors. Meso-CAR-T cells are CAR-T cells targeted mesothelin, which are over-expressed in tumor tissues of breast cancer patients. To improve the therapeutic effects, we combined it with rAd.sT, a transforming growth factor β signaling-targeted oncolytic adenovirus, to therapy breast cancer. In subcutaneous MDA-MB-231 xenograft of NSG mice, both rAd.sT and meso-CAR-T inhibited tumor growth, however combination therapy produced stronger inhibitory effects. Interestingly, rAd.sT reduced tumor burden at initial stage following vector treatments, while meso-CAR-T cells decreased tumor burden at a later stage. Moreover, meso-CAR-T could target tumor microenvironments, and combination therapy could enhance cytokines production, such as interleukin (IL)-6 and IL-12 in tumor microenvironment. In conclusion, combination of rAd.sT with meso-CAR-T produced much more impressive antitumor responses to breast cancer and its metastasis, which could be developed as a promising therapeutic strategy.