Acquired resistance towards immune defense during metastatic progression represents a secondary phenomenon

Co-Occurring Infections in Cancer Patients Treated with Checkpoint Inhibitors Significantly Increase the Risk of Immune-Related Adverse Events

Therapeutic antibodies designed to target three immune checkpoint proteins have been applied in the treatment of various malignancies, including small and non-small cell lung cancers, melanoma, renal cell carcinoma, and others. These treatments combat cancers by reactivating cytotoxic T cells. Nevertheless, this mode of action was found to be associated with a broad range of immune-related adverse events (irAEs), including pneumonitis, sarcoidosis, myocarditis, nephritis, colitis, and hepatitis. Depending on their severity, these irAEs often necessitate the suspension or discontinuation of treatment and, in rare instances, may lead to fatalities. We analyzed over nineteen million reports and identified over eighty thousand adverse event reports from patients treated with immune checkpoint inhibitors submitted to the Food and Drug Administration's Adverse Event Reporting System MedWatch. Reports concerning pembrolizumab, nivolumab, cemiplimab, avelumab, durvalumab, atezolizumab, and ipilimumab revealed a statistically significant association between the irAEs and concurrent infectious diseases for five out of seven treatments. Furthermore, the association trend was preserved across all three types of checkpoint inhibitors and each of the five individual therapeutic agent cohorts, while the remaining two showed the same trend, but an increased confidence interval, due to an insufficient number of records.

Co-occurring infections in cancer patients treated with checkpoint inhibitors significantly increase the risk of immune related adverse events

Therapeutic antibodies designed to target immune checkpoint proteins such as PD-1, PD-L1, and CTLA-4 have been applied in the treatment of various tumor types, including small and non-small cell lung cancers, melanoma, renal cell carcinoma, and others. These treatments combat cancers by reactivating CD8 cytotoxic T-cells. Nevertheless, this unique targeted mode of action was found to be associated with a broader range of immune-related adverse events, irAEs, affecting multiple physiological systems. Depending on their severity, these irAEs often necessitate the suspension or discontinuation of treatment and, in rare instances, may lead to fatal consequences. In this study we investigated over eighty thousand adverse event reports of irAEs in patients treated with PD-1, PD-L1, and CTLA-4 inhibitors. FDA Adverse Event Reporting System MedWatch submissions were used as the data source. These therapeutics included pembrolizumab, nivolumab, cemiplimab, avelumab, durvalumab, atezolizumab, and ipilimumab. The data analysis of these reports revealed a statistically significant association of immune related adverse events, including serious and life-threatening events in patients who experienced infectious disease during treatment. Additionally, the association trend was preserved across all the three classes of checkpoint inhibitors and each of the seven individual therapeutic agent cohorts.

Enhanced tumor growth and metastatic spread of an MH134 variant lacking a part of the MM antigen: a possible role of antibody-dependent cellular cytotoxicity in control of tumor growth and metastases

The role of antibody-dependent cellular cytotoxicity (ADCC) in host defense against tumor growth and metastasis was investigated with MH134, an MM antigen-positive murine hepatoma, and MH134-M, a variant with enhanced tumorigenesis and metastasis, in syngeneic C3H/HeN mice. When inoculated subcutaneously into C3H/HeN mice, MH134-M tumors grew more rapidly than did MH134 tumors and consistently metastasized to the draining lymph nodes, whereas MH134 tumors did not. Also, MH134-M exhibited a significantly greater lung colonization potential than did MH134, when inoculated intravenously into C3H/HeN mice. In BALB/c nu/nu mice, however, solid MH134 tumors grew and metastasized to the same extent as MH134-M, indicating that there is no significant intrinsic difference between these two tumor lines in proliferative or metastatic capacity. Enzyme-linked immunosorbent assay (ELISA) and immunoblotting, performed after SDS-PAGE analysis of cellular extracts with a monoclonal antibody (MAb) that recognizes a part of the MM-antigen, revealed that the cells of MH134-M lack at least a part of the MM antigen. Sera of C3H/HeN mice bearing solid MH134 tumors were found to contain anti-MM-antigen antibodies, when tested by immunoblotting of SDS-PAGE-developed materials. Cytotoxicity testing in which thioglycollate-induced peritoneal macrophages were used as effector cells revealed that antibodies present in sera strongly induced ADCC to MH134 but not to MH134-M. On the other hand, sera of MH134-M tumor-bearing C3H/HeN mice neither contained anti-MM-antigen antibodies nor induced ADCC to MH134 or MH134-M tumor cells. Intravenous injection of carrageenan into C3H/HeN mice bearing solid MH134 tumors significantly enhanced tumor growth, whereas the growth of subcutaneously injected MH134-M tumors was not influenced by this treatment. These results suggest that the enhanced tumorigenesis and metastasis of the MH134-M line in C3H/HeN mice are based, at least in part, on significant loss of the MM antigen and the resultant inability to induce ADCC-triggering antibody production during tumor growth.

Changes in adhesive properties of tumor cells do not necessarily influence metastasizing capacity

BSp6S and BSp73AS are two rat tumors which grow locally after intra-footpad (ifp) application. BSp73ASML and BSp6AS are variants, which metastasize via the lymphatics. Both variants have lost adherence properties, as shown by in vitro culture on plastic surfaces, suggesting that loss of adherence may be accompanied by increased metastasizing capacity. However, after growth of BSp6S and BSp73AS in vitro on poly(2-hydroxyethylmethacrylate) (polyHEMA)-coated plates, which resulted in loss of adherence and spreading, and subsequent intravenous (iv) or ifp injection of non-adherent tumor cells into syngeneic rats, metastasizing capacity was not increased. It is concluded that loss of adherence may facilitate metastatic spread, but certainly is not sufficient for initiation.