Variety Of Solid Tumor Models Research Articles

Abstract 1873: D3L-001, a novel bispecific antibody targeting HER2 and CD47, demonstrates potent preclinical efficacy in solid tumors

Abstract Background: HER2 is overexpressed in different solid tumors, including 10-20% breast and gastric cancers. Many HER2-targeted drugs, including trastuzumab, pertuzumab, lapatinib, trastuzumab emtansine (T-DM1), and trastuzumab deruxtecan (T-DXd), have been approved for treatment of HER2-positive early and metastatic breast cancer (BC). However, trials involving pertuzumab, lapatinib and T-DM1 have failed to provide significant clinical improvements in patients with HER2-positive gastric cancer (GC), suggesting differences in HER2 mediated disease biology between HER2-positive BC and GC. Recent studies have suggested efficacy of HER2 antibodies could be further enhanced by antibody-dependent cellular phagocytosis (ADCP) principally regulated by “don’t-eat-me” CD47 signals, which is overexpressed in many HER2-positive cancers and suppresses phagocytosis through binding to SIRPα. Methods: BC and GC cell lines were used. Monocytes were isolated from human PBMC and differentiated into macrophages, which were used for in vitro ADCP assays. In in vivo animal experiments, D3L-001 and comparator antibodies were examined for efficacy in solid tumor xenograft models. Results: D3L-001 was designed to have higher HER2 affinity (KD < 1 nM) than that of CD47 (KD >10 nM). With this unique design, D3L-001 showed preferential binding to HER2/CD47 double positive tumor cells as compared to CD47 single positive cells. D3L-001 showed better anti-tumor effect than trastuzumab in a panel of solid tumor models, including but not limited to BC and GC cell lines or patient derived xenografts. Immunohistochemistry (IHC) analysis was performed in tumor FFPE slides to evaluate expression of HER2 and CD47 in the efficacy tested models, and we observed that D3L-001 showed broad tumor growth inhibition in HER2 or CD47 high/low expression models. In both in vitro and in vivo studies using breast cancer HCC1954, JIMT-1 and gastric cancer N87 models, we observed a synergistic effect in the combination of Trastuzumab with Magrolimab. Moreover, D3L-001 showed a trend of better efficacy than the combination of Trastuzumab and Magrolimab. These results confirm the synergistic effect of dual-targeting HER2 and CD47 simultaneously and suggest advantage of using bispecific antibodies to confer such effect. D3L-001 also displayed potent and comparable in vivo efficacy as Enhertu in gastric N87 model, and it showed synergistic in vivo efficacy, when combining with Pertuzumab or Paclitaxel, in breast HCC1954, JIMT-1 and gastric cancer N87 models. Conclusion: D3L-001, a novel HER2×CD47 bsAb, demonstrated potent anti-tumor effect in a variety of solid tumor models via HER2 guided CD47 co-blocking. It also showed synergistic efficacy when combining with other anti-tumor agents. D3L-001 will be further evaluated in clinic for its potential as a novel treatment option in HER2-positive BC, GC and other solid tumors. Citation Format: Haopeng Rui, Xiaofeng Yang, Jiahao Chen, Jia Wang, Zhiqiang Zheng, Zhiqiang Chen, Jingtao Lu, Peggy Wu, Janet Chen, Allison Wang, George Chen. D3L-001, a novel bispecific antibody targeting HER2 and CD47, demonstrates potent preclinical efficacy in solid tumors [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 1873.

Abstract 4157: Using a multivalent immunotherapy platform to extend intratumoral therapeutic durability

Abstract Purpose: There is a critical need in immunotherapy drug development to enable focused and sustained immune cell modulation within a tumor to induce and propagate a system-wide anti-tumor response. We have developed a novel immunotherapy platform that could be used to generate geographically focused cancer cell growth inhibition or immune cell activation, thereby stimulating an anti-tumor immune response against primary solid tumors that can also travel to secondary metastases. Methods: Using published methods, we synthesized multivalent protein (MVP) conjugates by conjugating multiple copies (i.e. valency) of immune stimulating proteins, checkpoint inhibitors or anti-tumor antibodies to soluble, long-chain biopolymers. We verified that we can reproducibly generate MVP valencies ranging from 20-120 protein copies (±10%) per polymer backbone. We determined the binding affinity of these MVPs to their respective targets using biolayer interferometry and cell bioassays, and we measured the hydrodynamic radius of these immunotherapies using dynamic light scattering. Then, we injected fluorescently modified MVPs or their unconjugated counterparts directly into a variety of solid tumor models in mice. By taking longitudinal in vivo fluorescence measurements of the intratumoral (IT) drug signal over multiple days, we measured the IT half-life of each treatment. Results: Based on binding affinity measurements, we found that MVP potency increased directly with protein valency, and at high valency, the potency of MVPs were substantially greater than the unconjugated protein controls. Multivalent conjugation also increased the hydrodynamic radius of the MVPs to at least ten times larger than the unconjugated therapeutics. This large size was sufficient to slow the diffusion of MVP immunotherapies through dense tissues, such as solid tumors, as demonstrated by our in vivo studies. MVPs exhibited a higher IT drug signal with a more durable gradient within the tumor compared to the unconjugated controls, resulting in an extension of their IT half-lives by >5X in mouse solid tumors. Conclusions: The MVP platform can be used to modulate the potency and therapeutic durability for a wide range of immunotherapy targets. Further, the MVPs stay focused within the tumor after IT injection where they could generate a sustained anti-tumor immune response with minimal systemic exposure. Therefore, we expect MVP immunotherapies to have a better safety profile than IT or systemic delivery of an unconjugated therapeutic. We will continue to develop our internal MVP pipeline to finalize a candidate for IND-enabling studies. We are also seeking collaborations for co-development of additional immunotherapies that could benefit from the extended IT exposure and potency modulation enabled by the MVP platform. Citation Format: Livia Brier, Amy A. Twite, Adam Barnebey, Mavish Mahomed, Wesley M. Jackson. Using a multivalent immunotherapy platform to extend intratumoral therapeutic durability [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4157.

Abstract P027: Extending intratumoral therapeutic durability using a multivalent immunotherapy platform

Abstract Purpose: The risk of severe side effects has limited the development of immune cell activating immunotherapies. There is a critical need in immunotherapy drug development to enable focused and sustained immune cell activation within a tumor to induce a system-wide anti-tumor response. We have developed a novel immunotherapy platform that could be used to generate geographically focused cancer cell growth inhibition or immune cell activation, thereby stimulating an anti-tumor immune response against primary solid tumors that can also travel to secondary metastases. Methods: Using published methods, we synthesized multivalent protein (MVP) conjugates by conjugating multiple copies (i.e. valency) of immune stimulating proteins (e.g. Interleukin-15) or anti-tumor antibodies (e.g. anti-Epidermal Growth Factor Receptor) to soluble, long-chain biopolymers (e.g. carboxymethylcellulose or hyaluronic acid, ~700 kDa). We verified that we can reproducibly generate MVP valencies ranging from 20-120 protein copies (±10%) per polymer backbone. We determined the binding affinity of these MVPs to their respective targets using biolayer interferometry and cell bioassays, and we measured the hydrodynamic radius of these immunotherapies using dynamic light scattering. Then, we injected flurosecently modified MVPs or their unconjugated counterparts directly into a variety of solid tumor models in mice. By taking longitudinal in vivo fuorescence measurments of the intratumoral (IT) drug signal over multiple days, we measured the IT half-life of each treatment. Results: Based on binding affinity measurements, we found that MVP potency increased directly with their protein valency, and at high valency, the potency of MVPs were substantially greater than the unconjugated protein controls. Multivalent conjugation also increased the hydrodynamic radius of the MVPs to at least ten times larger than the unconjugated therapeutics. This large size was sufficient to slow the diffusion of MVP immunotherapies through dense tissues, such as solid tumors, as demonstrated by our in vivo studies. MVPs exhibited a higher IT drug signal with a more durable gradient within the tumor compared to the unconjugated controls, resulting in an extension of their IT half-lives by >5X in mouse solid tumors. Conclusions: The MVP platform can be used to modulate the potency and therapeutic durability for a wide range of immunotherapy targets. Further, the MVPs stay focused within the tumor after IT injection where they could generate a sustained anti-tumor immune response with minimal systemic exposure. Therefore, we expect MVP immunotherapies to have a better safety profile than IT or systemic delivery of an unconjugated therapeutic. We will continue to develop our internal MVP pipeline to finalize a candidate for IND-enabling studies. We are also seeking to collaborations for co-development of additional immunotherapies that could benefit from the extended IT exposure and potency modulation enabled by the MVP platform. Citation Format: Livia W. Brier, Mavish Mahomed, Amy A. Twite, Adam Barnebey, Wesley M. Jackson. Extending intratumoral therapeutic durability using a multivalent immunotherapy platform [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2021 Oct 5-6. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(1 Suppl):Abstract nr P027.

Acidosis and cancer: from mechanism to neutralization.

The extracellular pH of solid tumors is unequivocally acidic due to a combination of high rates of lactic acid production (a consequence of fermentative glycolytic metabolism) and poor perfusion. This has been documented by us and others in a wide variety of solid tumor models, primarily using magnetic resonance spectroscopic imaging (MRSI). This acidity contributes to tumor progression by inducing genome instability, promoting local invasion and metastases, inhibiting anti-tumor immunity, and conferring resistance to chemo- and radio-therapies. Systemic buffer therapies can neutralize tumor acidity and has been shown to inhibit local invasion and metastasis and improve immune surveillance in a variety of cancer model systems. This review will revisit the causes and consequences of acidosis by summarizing strategies used by cancer cells to adapt to acidosis, and how this acidity associated with carcinogenesis, metastasis, and immune function. Finally, this review will discuss how neutralization of acidity can be used to inhibit carcinogenesis and metastasis and improve anti-cancer immunotherapy.

Abstract 43: ASN004, a novel 5T4-targeted Dolaflexin ADC, achieves complete regressions and tumor-free survivors in a broad variety of solid tumor models

Abstract ASN004 is an Antibody Drug Conjugate (ADC) that targets the 5T4 oncofetal antigen (trophoblast glycoprotein). High expression of 5T4 is observed in a wide range of malignant tumors, while very limited expression is found in normal tissues. ASN004 incorporates a novel single-chain homo-dimer antibody, Fleximer® linker technology (Mersana Therapeutics), and several cytotoxic dolastatin (auristatin) analog warheads per ADC molecule with a drug/antibody ratio of ~15:1. ASN004 shows high affinity for the 5T4 antigen (Kd < 30 pM) and 5T4-expressing tumor cells; rapid cellular internalization; and potent, selective cytotoxicity. ASN004 provides complete tumor regressions and tumor-free survivors in multiple tumor xenograft models, derived from human tumor cell lines having both high and low 5T4 expression levels. Tumor-free survivors were achieved at doses that are well-tolerated, based on xenograft body weight measures and exploratory toxicology studies in pharmacologically-relevant non-human primates. As well, tumor-free survivors were achieved in xenograft tumor models following administration of a single dose of ASN004, as low as 1 mg/kg iv. The broad activity of ASN004 has been demonstrated by its superior efficacy in a head-to-head study against trastuzumab-DM1, in a low-5T4, high-HER2 expressing tumor xenograft model. Finally, tumor xenografts that initially responded to ASN004 and later showed tumor regrowth, had not developed resistance and responded well to subsequent treatment with ASN004. Overall, ASN004 is demonstrated to be an ADC with high therapeutic potential in multiple tumor types, encompassing a wide range of 5T4-expression levels. IND-enabling toxicology studies are ongoing, in preparation for advancement to clinical studies in patients with solid tumors. Citation Format: Roger A. Smith, David J. Zammit, Sanjeeva P. Reddy. ASN004, a novel 5T4-targeted Dolaflexin ADC, achieves complete regressions and tumor-free survivors in a broad variety of solid tumor models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 43. doi:10.1158/1538-7445.AM2017-43

Arsenic trioxide inhibits HCCLM3 cells invasion through de novo ceramide synthesis and sphingomyelinase-induced ceramide production

Arsenic trioxide (ATO) has shown anticancer activity against a variety of solid tumor models through induction of apoptosis, promotion of cellular differentiation, and inhibition of cellular invasive ability. The present study investigated the role of ceramide in regulating the invasive activity of hepatoma carcinoma HCCLM3 cells during ATO treatment. We found that ATO treatment inhibited HCCLM3 cell invasion and downregulated matrix metalloproteinase-9 (MMP-9) protein levels in a concentration-dependent manner. ATO also dose dependently induced the generation and accumulation of ceramide in HCCLM3 cells. Blockage of intracellular ceramide production through the inhibition of de novo ceramide synthesis or the hydrolysis of sphingomyelin increased the invasive ability and upregulated MMP-9 protein levels. The findings of this study indicated that ATO induced ceramide production through de novo ceramide synthesis and the hydrolysis of sphingomyelin and suggested that ceramide accumulation in response to ATO stimuli may play an important role in cancer therapy.