Supplementary Figure 5 shows that bemcentinib potentiated efficacy of chemo-immunotherapy

Supplementary Figure 6 shows that bemcentinib treatment enhances induction of interferon stimulated gene

Supplementary Figure 3 shows IFNAR1 knockdown blocked the interferon-inducing effect of bemcentinib

Supplementary Figure 4 shows MK-2206 treatment reduces the phosphorylation of AKT

Supplementary Figure 1 shows Axl kinase inhibition enhanced type 1 IFN response in human melanoma cell lines

Supplementary Figure 7 shows that bemcentinib treatment enhances induction of type 1 and type II IFN response genes

Supplementary Figure 2 showsAxl kinase inhibition suppresses EMT, cell survival and growth associated responses, and enhances type 1 IFN, antiviral, proinflammatory and innate and adaptive immune response genes and proteins

AXL is an important negative regulator of type I IFN responses during viral infections. In the context of tumors, AXL is associated with driving tumor progression, spread, immune evasion, and therapy resistance. AXL regulation of tumor cell-intrinsic IFN responses remains unexplored. We show that AXL suppresses tumor cell-intrinsic IFN responses by inhibiting the cytosolic DNA sensor cGAS via an AKT-dependent pathway. AXL inhibition in combination with chemoimmunotherapy demonstrated potent antitumor effects in poorly immunogenic tumors that are refractory to immunotherapy. The inhibition of AXL correlated with increased cGAMP levels, activation of IFN, and enhanced infiltration of T cells and NK cells into the tumor microenvironment. These findings reveal a novel role for AXL in suppressing IFN within tumors and support AXL targeting as a promising strategy in conjunction with chemoimmunotherapy for treating therapy-resistant tumors.

Supplementary Figures S1 to S6 with figure legends

Supplementary Materials and Methods

The receptor tyrosine kinase AXL promotes tumor progression, metastasis, and therapy resistance through the induction of epithelial-mesenchymal transition (EMT). Here, we found that activation of AXL resulted in the phosphorylation of TANK-binding kinase 1 (TBK1) and the downstream activation of AKT3 and Snail, a transcription factor critical for EMT. Mechanistically, we showed that TBK1 directly bound to and phosphorylated AKT3 in a manner dependent on the multiprotein complex mTORC1. Upon activation, AKT3 interacted with and promoted the nuclear accumulation of Snail, which led to increased EMT as assessed by marker abundance. In human pancreatic ductal adenocarcinoma tissue, nuclear AKT3 colocalized with Snail and correlated with worse clinical outcomes. Primary mouse pancreatic cancer cells deficient in AKT3 showed reduced metastatic spread in vivo, suggesting selective AKT3 inhibition as a potential therapeutic avenue for targeting EMT in aggressive cancers.

Background and aimsMetabolic dysfunction-associated steatohepatitis (MASH) is a significant health concern with limited treatment options. AXL, a receptor tyrosine kinase activated by the GAS6 ligand, promotes MASH through activation of hepatic stellate cells and inflammatory macrophages. This study identified cell subsets affected by MASH progression and the effect of AXL inhibition.MethodsMice were fed chow or different fat-enriched diets to induce MASH, and small molecule AXL kinase inhibition with bemcentinib was evaluated. Gene expression was measured by qPCR. Time-of-flight mass cytometry (CyTOF) used single cells from dissociated livers, acquired on the Fluidigm Helios, and cell populations were studied using machine learning.ResultsIn mice fed different fat-enriched diets, liver steatosis alone was insufficient to elevate plasma soluble AXL (sAXL) levels. However, in conjunction with inflammation, sAXL increases, serving as an early indicator of steatohepatitis progression. Bemcentinib, an AXL inhibitor, effectively reduced proinflammatory responses in MASH models, even before fibrosis appearance. Utilizing CyTOF analysis, we detected a decreased population of Kupffer cells during MASH while promoting infiltration of monocytes/macrophages and CD8+ T cells. Bemcentinib partially restored Kupffer cells, reduced pDCs and GzmB− NK cells, and increased GzmB+CD8+ T cells and LSECs. Additionally, AXL inhibition enhanced a subtype of GzmB+CD8+ tissue-resident memory T cells characterized by CX3CR1 expression. Furthermore, bemcentinib altered the transcriptomic landscape associated with MASH progression, particularly in TLR signaling and inflammatory response, exhibiting differential cytokine expression in the plasma, consistent with liver repair and decreased inflammation.ConclusionOur findings highlight sAXL as a biomarker for monitoring MASH progression and demonstrate that AXL targeting shifted liver macrophages and CD8+ T-cell subsets away from an inflammatory phenotype toward fibrotic resolution and organ healing, presenting a promising strategy for MASH treatment.

Soluble biomarkers are paramount to personalized medicine. However, the in vivo turnover and biodistribution of soluble proteins is seldom characterized. The cleaved extracellular domain of the AXL receptor (sAXL) is a prognostic biomarker in several diseases and a predictive marker of AXL targeting agents. Plasma sAXL reflects a balance between production in tissues with lymphatic transport into the circulation and removal from blood by degradation or excretion. It is unclear how this transport cycle affects plasma sAXL levels that are the metric for biomarker development. Radiolabeled mouse sAxl was monitored after intravenous injection to measure degradation and urinary excretion of sAxl, and after intradermal injection to mimic tissue or tumor production. sAxl was rapidly taken-up and degraded by the liver and kidney cortex. Surprisingly, intact sAxl was detectable in urine, indicating passage through the glomerular filter and a unique sampling opportunity. The structure of sAxl showed an elongated, flexible molecule with a length of 18 nm and a thickness of only 3 nm, allowing passage through the glomerulus and excretion into the urine. Intradermally injected sAxl passed through local and distant lymph nodes, followed by uptake in liver and kidney cortex. Low levels of sAxl were seen in the plasma, consistent with an extended transit time from local tissue to circulation. The rapid plasma clearance of sAxl suggests that steady-state levels in blood will sensitively and dynamically reflect the rate of production of sAxl in the tissues but will be influenced by perturbations of liver and kidney function.

IntroductionThe incidence of chronic kidney disease (CKD) is increasing, in parallel with risk factors including obesity and diabetes mellitus. AXL plays a central role in CKD, providing a rationale to evaluate clinical AXL targeting agents.MethodsTo determine the efficacy and underlying molecular mechanisms of AXL inhibition in CKD, we employed a murine unilateral ureteral obstruction (UUO) model preventively treated with a selective AXL kinase inhibitor (bemcentinib) during disease progression. We isolated kidneys at an early (3 days) or late (15 days) timepoint and profiled the cell populations using mass cytometry.ResultsPreventive treatment with bemcentinib significantly attenuated fibrosis in the UUO model. The anti-fibrotic effect correlated with a decrease in mesangial cells and inhibition of innate immune cell infiltration, while the proportion of epithelial cells increased. We mapped AXL expression to a unique network of cells in the kidney: mesangial cells, pericytes, macrophages and dendritic cells.DiscussionWe propose that AXL targeting affects an important cellular interaction network underlying fibrotic progression. These results support the clinical application of AXL targeting agents to treat CKD.

AbstractThe survival rate for patients with head and neck cancer (HNC) diagnosed with cervical lymph node (cLN) or distant metastasis is low. Genomic alterations in the HRAS oncogene are associated with advanced tumor stage and metastasis in HNC. Elucidation of the molecular mechanisms by which mutated HRAS (HRASmut) facilitates HNC metastasis could lead to improved treatment options for patients. Here, we examined metastasis driven by mutant HRAS in vitro and in vivo using HRASmut human HNC cell lines, patient-derived xenografts, and a novel HRASmut syngeneic model. Genetic and pharmacological manipulations indicated that HRASmut was sufficient to drive invasion in vitro and metastasis in vivo. Targeted proteomic analysis showed that HRASmut promoted AXL expression via suppressing the Hippo pathway and stabilizing YAP1 activity. Pharmacological blockade of HRAS signaling with the farnesyltransferase inhibitor tipifarnib activated the Hippo pathway and reduced the nuclear export of YAP1, thus suppressing YAP1-mediated AXL expression and metastasis. AXL was required for HRASmut cells to migrate and invade in vitro and to form regional cLN and lung metastases in vivo. In addition, AXL-depleted HRASmut tumors displayed reduced lymphatic and vascular angiogenesis in the primary tumor. Tipifarnib treatment also regulated AXL expression and attenuated VEGFA and VEGFC expression, thus regulating tumor-induced vascular formation and metastasis. Our results indicate that YAP1 and AXL are crucial factors for HRASmut-induced metastasis and that tipifarnib treatment can limit the metastasis of HNC tumors with HRAS mutations by enhancing YAP1 cytoplasmic sequestration and downregulating AXL expression.Significance:Mutant HRAS drives metastasis of head and neck cancer by switching off the Hippo pathway to activate the YAP1–AXL axis and to stimulate lymphovascular angiogenesis.

Table showing inhibition of kinases

Levels of Akt and p70 S6 kinase after treatment with Pim kinase inhibitors

This file contains 6 supplementary figures and 5 supplementary Tables. Supplementary Figure S1 - Protein expression pattern of AXL in ccRCC specimens. Supplementary Figure S2 - Response rates, Survival and Biomarker analyses according to AXLneg, AXLlow and AXLhigh expression Supplementary Figure S3 - ORR and Progression-Free Survival according to PD-L1 Status alone or by grouping AXL expression plus PD-L1 status Supplementary Figure S4 - High AXL expression plus PD-L1 TC positivity is associated with worse OS in Nivolumab-treated patients in IMDC intermediate-risk/poor-risk group Supplementary Figure S5 - VHL status does not interfere with outcomes or AXL expression upon treatment with Nivolumab Supplementary Figure S6 - Biomarker distribution across AXL groups stratified based on VHL status

STK11 (LKB1) is a tumor suppressor, and loss-of-function mutations contribute to tumorigenesis. Mutations in the STK11 gene (STK11m) are present in ~ 20% of NSCLCs and are associated with poor response to chemotherapy and immune checkpoint inhibition (ICI) resulting in inferior survival outcomes. STK11m tumors are characterized by high oxidative stress/ROS, EMT, enhanced replication stress tolerance, resistance to DNA damage and a highly immunosuppressive tumor microenvironment with limited activation and expansion of anti-tumor CD8 T-cells. AXL, a member of the TAM family of receptor tyrosine kinases, is activated in response to cellular stress such as ROS and hypoxia. AXL expression and activation is associated with EMT and drug resistance, tumor tolerance towards oxidative stress and apoptosis, as well as an immunosuppressed tumor microenvironment. We have previously shown that selective AXL inhibition by bemcentinib potentiated ICI in STK11m NSCLC preclinical models and led to objective clinical response in individuals with STK11m NSCLC receiving bemcentinib and pembrolizumab (NCT03184571). Data from this clinical study, an independent real-world cohort of patients studied at the Haukeland Hospital in Bergen, Norway (REC 45562) and published results1, suggest AXL is expressed in ~ 80% of NSCLCs harboring a STK11m, indicating AXL expression is a characteristic of STK11m NSCLC and confirming that AXL is an attractive target in STK11m NSCLC. Inhibition of AXL in dendritic cells has been shown to increase ICI responses in preclinical models of STK11m NSCLC1. The relative contribution of targeting AXL in STK11m tumor cells vs the tumor microenvironment, and the impact on tumor cells after tumor cell targeting needs further exploration. Transcriptional analysis of STK11m and STK11wt sequences from public datasets, NCT03184571 patients and NSCLC cell lines identified transcriptional signatures consistent with the known roles of STK11 in DNA damage response and immunosuppression. Treatment of STK11m NSCLC cell lines with the AXL inhibitor bemcentinib led to a reduction in the STK11-associated DDR signature and increase in inflammatory signatures demonstrating the impact of AXL targeting on tumor cells. Due to the high unmet medical need in individuals harboring a STK11 mutation, the encouraging efficacy in the NCT03184571 clinical trial and the high incidence of AXL protein expression in STK11m tumors, a global, open-label Phase 1b/2a trial to determine the safety, tolerability and anti-tumor activity of bemcentinib with SOC (pembrolizumab, pemetrexed and carboplatin) in 1L advanced/metastatic non-squamous NSCLC patients with STK11 mutations and no actionable mutations is currently enrolling. The Phase 1b part of the study will evaluate the safety and tolerability of bemcentinib regardless of STK11 status, whereas the Phase 2a part will assess the efficacy in NSCLC patients with STK11 mutations. 1 Li et al., 2022; Cell Rep Med., PMID: 35492873 Citation Format: Magnus Blø, Austin Rayford, Noëlly Madeleine, Fabian Gärtner, Dana Bohan, Natalie Ruggio, Huiyu Li, Luc Girard, Rolf Brekken, John Minna, Marianne Ånerud, Wendy Maury, Claudia Gorcea-Carson, Gro Gausdal, David R. Micklem, Nigel McCracken. AXL as a therapeutic target in STK11 mutant NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3245.

This file contains supplementary Figures