Search

Supplementary Figure S1-S8

Supplementary Table 1: CRASH-IT switches, variant constructs lacking one or more functional domains and codon optimized DNA sequences

Adoptive transfer of genetically modified or donor-derived T cells can efficiently eradicate human tumors but is also frequently associated with major toxicity. There are several switches that can be used to kill the infused cell pool in the case of major toxicity, but the irreversible nature of these suicide switches means that the therapeutic effect is lost when they are used. To address this issue, we engineered a small-molecule responsive genetic safety switch that in the absence of drug robustly blocked cytotoxicity and cytokine expression of primary human T cells. Upon administration of drug, T-cell functions were restored in a reversible and titratable manner. We showed that this T-cell switch was universal, as it could be combined with endogenous or transduced T-cell receptors (TCR), as well as chimeric antigen receptors. The modular nature of the Chemically Regulated - SH2-delivered Inhibitory Tail (CRASH-IT) switch concept, in which inhibitory domains are brought to activating immune receptors in a controlled manner, makes it a versatile platform to regulate the activity of cell products that signal through immunoreceptor tyrosine-based activation motif (ITAM)–containing receptors.

Although immune checkpoint blockade (ICB) has shown remarkable clinical benefit in a subset of patients with melanoma and lung cancer, most patients experience no durable benefit. The receptor tyrosine kinase AXL is commonly implicated in therapy resistance and may serve as a marker for therapy-refractory tumors, for example in melanoma, as we previously demonstrated. Here, we show that enapotamab vedotin (EnaV), an antibody–drug conjugate targeting AXL, effectively targets tumors that display insensitivity to immunotherapy or tumor-specific T cells in several melanoma and lung cancer models. In addition to its direct tumor cell killing activity, EnaV treatment induced an inflammatory response and immunogenic cell death in tumor cells and promoted the induction of a memory-like phenotype in cytotoxic T cells. Combining EnaV with tumor-specific T cells proved superior to either treatment alone in models of melanoma and lung cancer and induced ICB benefit in models otherwise insensitive to anti–PD-1 treatment. Our findings indicate that targeting AXL-expressing, immunotherapy-resistant tumors with EnaV causes an immune-stimulating tumor microenvironment and enhances sensitivity to ICB, warranting further investigation of this treatment combination.Significance:These findings show that targeting AXL-positive tumor fractions with an antibody–drug conjugate enhances antitumor immunity in several humanized tumor models of melanoma and lung cancer.

Supplementary Table 1 Differentially expressed genes of PCA3, comparing EnaV-treated tumors to control tumors

Adoptive transfer of genetically modified or donor-derived T cells can efficiently eradicate human tumors but is also frequently associated with major toxicity. There are several switches that can be used to kill the infused cell pool in the case of major toxicity, but the irreversible nature of these suicide switches means that the therapeutic effect is lost when they are used. To address this issue, we engineered a small-molecule responsive genetic safety switch that in the absence of drug robustly blocked cytotoxicity and cytokine expression of primary human T cells. Upon administration of drug, T-cell functions were restored in a reversible and titratable manner. We showed that this T-cell switch was universal, as it could be combined with endogenous or transduced T-cell receptors (TCR), as well as chimeric antigen receptors. The modular nature of the Chemically Regulated - SH2-delivered Inhibitory Tail (CRASH-IT) switch concept, in which inhibitory domains are brought to activating immune receptors in a controlled manner, makes it a versatile platform to regulate the activity of cell products that signal through immunoreceptor tyrosine-based activation motif (ITAM)–containing receptors.

Although immune checkpoint blockade (ICB) has shown remarkable clinical benefit in a subset of patients with melanoma and lung cancer, most patients experience no durable benefit. The receptor tyrosine kinase AXL is commonly implicated in therapy resistance and may serve as a marker for therapy-refractory tumors, for example in melanoma, as we previously demonstrated. Here, we show that enapotamab vedotin (EnaV), an antibody–drug conjugate targeting AXL, effectively targets tumors that display insensitivity to immunotherapy or tumor-specific T cells in several melanoma and lung cancer models. In addition to its direct tumor cell killing activity, EnaV treatment induced an inflammatory response and immunogenic cell death in tumor cells and promoted the induction of a memory-like phenotype in cytotoxic T cells. Combining EnaV with tumor-specific T cells proved superior to either treatment alone in models of melanoma and lung cancer and induced ICB benefit in models otherwise insensitive to anti–PD-1 treatment. Our findings indicate that targeting AXL-expressing, immunotherapy-resistant tumors with EnaV causes an immune-stimulating tumor microenvironment and enhances sensitivity to ICB, warranting further investigation of this treatment combination. Significance: These findings show that targeting AXL-positive tumor fractions with an antibody–drug conjugate enhances antitumor immunity in several humanized tumor models of melanoma and lung cancer.

Despite the success of immune checkpoint blockade (ICB) most patients fail to respond durably, in part owing to reduced interferon gamma (IFNγ) sensitivity. Thus, elevating tumor IFNγ-receptor 1 (IFNγ-R1) expression to enhance IFNγ-mediated cytotoxicity is of potential clinical interest. Here, we show that increased IFNγ-R1 expression sensitizes tumors to IFNγ-mediated killing. To unveil the largely undefined mechanism governing IFNγ-R1 expression, we performed a genome-wide CRISPR/Cas9 screen for suppressors of its cell surface abundance. We uncovered STUB1 as key mediator of proteasomal degradation of the IFNγ-R1/JAK1 complex. STUB1 inactivation amplified IFNγ signaling, thereby sensitizing to cytotoxic T cells, but also inducing PD-L1. STUB1 loss in a rational combination with PD-1 blockade strongly inhibited melanomas in vivo. Clinically corroborating these results, a STUB1-KO gene signature was strongly associated with anti-PD-1 response. These results uncover STUB1 as pivotal regulator of IFNγ tumor signaling and provide a rationale for its inhibition combined with anti-PD-1.