Application of CT Image Technology Based on Nearest Neighbor Propagation Clustering Segmentation Algorithm in Lung Cancer Radiotherapy

Objective. This paper uses the nearest neighbor propagation clustering segmentation algorithm to explore the impact of PET/CT image segmentation technology on lung cancer radiotherapy planning. Methods. In this paper, PET/CT scan was performed on 12 patients with nonmetastatic lung cancer. The self-written automatic segmentation program based on PCNN model is used to segment the PET target area, and then the tumor target area is manually sketched based on CT images and PET/CT images, and the intensity-modulated radiotherapy plan is formulated with the same parameters. Target volume and dose distribution were analyzed. Results. There was no statistical difference between the PET automatic segmentation target area and the PET manual contouring target area ( P < 0.05 ); the segmentation method was accurate and reliable; the difference between the CT manual contouring target area was statistically significant ( P 0.05 ). Conclusion. Based on the nearest neighbor propagation clustering segmentation algorithm, PET/CT image segmentation technology improves the accuracy of tumor target area delineation. The radiotherapy plan based on the segmentation target area can reduce the normal tissue exposure range and reduce the incidence of complications.

IL-1 SRS Without the Bunker: Introduction and Clinical Experience of ZAP-X Gyroscopic Radiosurgery

Each year more than two million patients worldwide are potential candidates for SRS, yet due to the significant costs and complexities of historical delivery systems, only 150,000 patients currently receive such treatment. Japan Shonin-cleared in 2020, ZAP Surgical’s ZAP-X Gyroscopic Radiosurgery platform was designed to solve this challenge, and ultimately bring world-class SRS to more patients in more places. ZAP-X is recognized for being the first and only vault-free SRS delivery system, thereby typically eliminating the need for providers to build costly shielded radiation treatment rooms. Utilizing a modern linear accelerator to produce radiation, ZAP-X is also the first and only dedicated radiosurgery system to no longer require Cobalt-60 radioactive sources, thereby eliminating the significant costs to license, secure and regularly replace live radioactive isotopes. Built on a distinctive dual-gimbaled gantry design, the ZAP-X system uses gyroscopic mobility to direct radiosurgical beams from hundreds of unique angles to precisely concentrate radiation on the tumor target. This pioneering approach supports the clinical objective of protecting healthy brain tissue and patient neuro-cognitive function, as well as enable future potential SRS re-treatments without the unnecessary risks associated with multi-purpose radiation delivery technologies.

894 The bispecific innate cell engagers AFM13 (CD30/CD16A) and AFM24 (EGFR/CD16A) increase the fraction of tumor target-responsive NK cells and boost serial killing

BackgroundThe use of bispecific natural killer (NK) cell engagers has emerged as a successful strategy for immune cell activation and killing of tumor cells through antibody-dependent cellular cytotoxicity (ADCC). Among these, tetravalent, bispecific innate cell engagers (ICE®) with specificity for the activating receptor CD16A selectively triggering innate responses from NK cells or macrophages represent the most clinically advanced concept. The CD30/CD16A specific ICE® AFM13, has shown efficacy in patients with CD30+ lymphomas as monotherapy1 and combination therapy with check-point inhibitors2 and most recently in combination with adoptive NK cell therapy.3 The EGFR/CD16A specific ICE® AFM24, targeting a variety of solid tumors like colorectal, or lung cancer with a unique mode of action independent of EGFR signaling inhibition, is currently evaluated in an ongoing Ph1/2a clinical study.MethodsWe used a microchip-based screening with single cell resolution4 to elucidate the dynamic responses of individual NK cells towards tumor target cells upon treatment with AFM13 or AFM24.ResultsWe found that AFM13 and AFM24 mediated potent activation of NK cells, leading to increased responsive cytotoxic NK cells and significantly increased the number of NK cells that exerted engagement with multiple target cells rendering these NK cells serial killers. Strikingly, bispecific ICE® molecules triggered stronger cytotoxic responses compared to monoclonal antibodies. One suggested strategy to boost killing by NK cells is to use molecular inhibitors or protein constructs that prevent shedding of CD16.5 However, previous results have shown that this can lead to impaired detachment from target cells, reducing the capacity for an individual NK cell to form serial contacts to target cells.6 We observed that the elevated NK cell killing induced by ICE® molecules was largely conserved when cells were treated with the shedding inhibitor Batimastat. Analysis of the functional dynamics of NK cells revealed that inhibition of CD16 shedding prevented NK cell detachment from target cells, resulting in cell cluster formation. This might strongly impact targeting of distant tumor cells by an individual NK cell thus limiting its anti-tumoral activity.ConclusionsIn conclusion, we show that both AFM13 and AFM24 increase the fraction of tumor-target responsive NK cells and boost serial killing of target cells by individual NK cells. Based on these data, ICE® molecules can be characterized as potent anti-tumoral agents leveraging the enormous potential of NK cells while maintaining crucial features of NK cell biology.AcknowledgementsWe thank members of the Önfelt lab for their valuable help and feedback.ReferencesSawas A, Elgedawe H, Vlad G, Lipschitz M, Chen P-H, Rodig SJ, et al. Clinical and biological evaluation of the novel CD30/CD16A tetravalent bispecific antibody (AFM13) in relapsed or refractory CD30-positive lymphoma with cutaneous presentation: a biomarker phase Ib/IIa study (NCT03192202). Blood 2018;132(Supplement 1):2908–2908.Bartlett NL, Herrera AF, Domingo-Domenech E, Mehta A, Forero-Torres A, Garcia-Sanz R, et al. A phase 1b study of AFM13 in combination with pembrolizumab in patients with relapsed or refractory Hodgkin lymphoma. Blood 2020. Blood 2020;136(21):2401–2409.Kerbauy LN, Marin ND, Kaplan M, Banerjee PP, Berrien-Elliott MM, Becker-Hapak M, et al. Combining AFM13, a bispecific CD30/CD16 antibody, with cytokine-activated blood and cord blood–derived NK cells facilitates CAR-like responses against CD30 + malignancies. Clin Cancer Res Epub 2021.Guldevall K, Brandt L, Forslund E, Olofsson K, Frisk TW, Olofsson PE, et al. Microchip screening platform for single cell assessment of NK cell cytotoxicity. Front Immunol 2016;7:119.Romee R, Foley B, Lenvik T, Wang Y, Zhang B, Ankarlo D, et al. NK cell CD16 surface expression and function is regulated by a disintegrin and metalloprotease-17 (ADAM17). Blood 2013;121(18):3599–608.Srpan K, Ambrose A, Karampatzakis A, Saeed M, Cartwright ANR, Guldevall K, et al. Shedding of CD16 disassembles the NK cell immune synapse and boosts serial engagement of target cells. J Cell Biol 2018;217(9):3267–83.Ethics ApprovalThis work was performed with NK cells from healthy anonymous blood donors, which requires no ethical permit according to local regulations.

The Regulatory Role of RNA Metabolism Regulator TDP-43 in Human Cancer

TAR-DNA-binding protein-43 (TDP-43) is a member of hnRNP family and acts as both RNA and DNA binding regulator, mediating RNA metabolism and transcription regulation in various diseases. Currently, emerging evidence gradually elucidates the crucial role of TDP-43 in human cancers like it is previously widely researched in neurodegeneration diseases. A series of RNA metabolism events, including mRNA alternative splicing, transport, stability, miRNA processing, and ncRNA regulation, are all confirmed to be closely involved in various carcinogenesis and tumor progressions, which are all partially regulated and interacted by TDP-43. Herein we conducted the first overall review about TDP-43 and cancers to systematically summarize the function and precise mechanism of TDP-43 in different human cancers. We hope it would provide basic knowledge and concepts for tumor target therapy and biomarker diagnosis in the future.

44/47 Scandium Labelled Cholecystokinin Derivative for Cancer Theragnostics

The cholecystokinin (CCK) receptors are known to overexpress in various types of tumors. Through a previous study, a cyclic CCK analogue, DOTA-[Nle]-cCCK, was confirmed to have high in vivo stability and the tumor target ability of DOTA-[Nle]-cCCK capable of binding to the CCK receptor was confirmed through Lu-177 labeling. In this study, DOTA-[Nle]-cCCK was labeled with the pair-isotope, Sc-44/47, to confirm a technology that possibly could be applicable to radiopharmaceutical. First, we confirmed that the CCK receptor was overexpressed in AR42J, a cancer cell overexpressed in cancer tissue, and measured the binding ability of the receptor and DOTA-[Nle]-cCCK. We established the labeling method of radioactive scandium, and we confirmed that the Sc-44 labeled DOTA-[Nle]-cCCK administered to mice remained mostly in the bladder within an hour. Cell experiments with Sc-47 labeled DOTA-[Nle]-cCCK confirmed that more than half of the cancer cells were killed at a concentration of 5 MBq/ml. Through this study, we were able to confirm the diagnostic/therapeutic applicability of the DOTA-[Nle]-cCCK label with pair-isotope Sc-44/47.

Selection of Human Single Domain Antibodies (sdAb) Against Thymidine Kinase 1 and Their Incorporation Into sdAb-Fc Antibody Constructs For Potential Use In Cancer Therapy.

Thymidine Kinase 1 (TK1) is primarily known as a cancer biomarker with good prognostic capabilities for liquid and solid malignancies. However, recent studies targeting TK1 at protein and mRNA levels have shown that TK1 may be useful as a tumor target. In order to examine the use of TK1 as a tumor target, it is necessary to develop therapeutics specific for TK1. Single domain antibodies (sdAbs), represent an exciting approach for the development of immunotherapeutics due to their cost-effective production and higher tumor penetration than conventional antibodies. In this study, we isolated sdAb fragments specific to human TK1 from a human sdAb library. A total of 400 sdAbs were screened through 5 rounds of selection by monoclonal phage ELISA. The most sensitive sdAb fragments were selected as candidates for preclinical testing. The sdAb fragments showed specificity for human TK1 in phage ELISA, Western blot analysis and had a limit of detection of 3.9 ng/ml for 4-H-TK1_A1 and 1.9 ng/ml for 4-H-TK1_D1. The antibody fragments were successfully expressed and used for detection of membrane associated TK1 (mTK1) through flow cytometry on cancer cells [lung (~95%), colon (~87%), breast (~53%)] and healthy human mono nuclear cells (MNC). The most sensitive antibody fragments, 4-H-TK1_A1 and 4-H-TK1_D1 were fused to an engineered IgG1 Fc fragment. When added to cancer cells expressing mTK1 co-cultured with human MNC, the anti-TK1-sdAb-IgG1_A1 and D1 were able to elicit a significant antibody-dependent cell-mediated cytotoxicity (ADCC) response by human MNCs against lung cancer cells compared to isotype controls (P<0.0267 and P<0.0265, respectively). To our knowledge this is the first time that the isolation and evaluation of human anti TK1 single domain antibodies using phage display technology has been reported. The antibody fragments isolated here may represent a valuable resource for the detection and the targeting of TK1 in tumor cells

Scaffolding Protein IQGAP1 is Dispensable But Its Overexpression Promotes Hepatocellular Carcinoma via YAP1 Signaling

IQ motif–containing GTPase-activating protein 1 (IQGAP1) is a ubiquitously expressed scaffolding protein that is overexpressed in a number of cancers, including liver cancer, and is associated with pro-tumorigenic processes such as cell proliferation, motility, and adhesion. IQGAP1 can integrate multiple signaling pathways and could be an effective anti-tumor target. Therefore, we examined the role for IQGAP1 in tumor initiation and promotion during liver carcinogenesis. We found that ectopic overexpression of IQGAP1 in the liver is not sufficient to initiate tumorigenesis. Moreover, the tumor burden and cell proliferation in the DEN-induced liver carcinogenesis model in Iqgap1-/- mice maybe driven by MET signaling. In contrast, IQGAP1 overexpression enhanced YAP activation and subsequent NUAK2 expression to accelerate and promote hepatocellular carcinoma (HCC) in a clinically relevant model expressing activated (S45Y) β-catenin and MET. Here, increasing IQGAP1 expression in vivo does not alter β-catenin or MET activation; instead, it promotes YAP activity. Overall, we demonstrate that although IQGAP1 expression is not required for HCC development, the gain of IQGAP1 function promotes the rapid onset and increased liver carcinogenesis. Our results show that an adequate amount of IQGAP1 scaffold is necessary to maintain the quiescent status of the liver.

Design Strategy for the EPR Tumor-Targeting of 1,2-Bis(sulfonyl)-1-alkylhydrazines

A design strategy for macromolecular prodrugs is described, that are expected to exhibit robust activity against most solid tumor types while resulting in minimal toxicities to normal tissues. This approach exploits the enhanced permeability, and retention (EPR) effect, and utilizes carefully engineered rate constants to selectively target tumor tissue with short-lived cytotoxic moieties. EPR based tumor accumulation (half-life ~ 15 h) is dependent upon the ubiquitous abnormal solid tumor capillary morphology and is expected to be independent of individual tumor cell genetic variability that leads to resistance to molecularly targeted agents. The macromolecular sulfonylhydrazine-based prodrugs hydrolyze spontaneously with long half-life values (~10 h to >300 h dependent upon their structure) resulting in the majority of the 1,2-bis(sulfonyl)-1-alkylhydrazines (BSHs) cytotoxic warhead being released only after tumor sequestration. The very short half-life (seconds) of the finally liberated BSHs localizes the cytotoxic stress to the tumor target site by allowing insufficient time for escape. Thus, short lifespan anticancer species are liberated, and exhibit their activity largely within the tumor target. The abnormal tumor cell membrane pH gradients favor the uptake of BSHs compared to that of normal cells, further enhancing their selectivity. The reliance on physicochemical/chemical kinetic parameters and the EPR effect is expected to reduce response variability, and the acquisition of resistance.