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AKS-452 is a biologically-engineered vaccine comprising an Fc fusion protein of the SARS-CoV-2 viral spike protein receptor binding domain antigen (Ag) and human IgG1 Fc (SP/RBD-Fc) in clinical development for the induction and augmentation of neutralizing IgG titers against SARS-CoV-2 viral infection to address the COVID-19 pandemic. The Fc moiety is designed to enhance immunogenicity by increasing uptake via Fc-receptors (FcγR) on Ag-presenting cells (APCs) and prolonging exposure due to neonatal Fc receptor (FcRn) recycling. AKS-452 induced approximately 20-fold greater neutralizing IgG titers in mice relative to those induced by SP/RBD without the Fc moiety and induced comparable long-term neutralizing titers with a single dose vs. two doses. To further enhance immunogenicity, AKS-452 was evaluated in formulations containing a panel of adjuvants in which the water-in-oil adjuvant, Montanide™ ISA 720, enhanced neutralizing IgG titers by approximately 7-fold after one and two doses in mice, including the neutralization of live SARS-CoV-2 virus infection of VERO-E6 cells. Furthermore, ISA 720-adjuvanted AKS-452 was immunogenic in rabbits and non-human primates (NHPs) and protected from infection and clinical symptoms with live SARS-CoV-2 virus in NHPs (USA-WA1/2020 viral strain) and the K18 human ACE2-trangenic (K18-huACE2-Tg) mouse (South African B.1.351 viral variant). These preclinical studies support the initiation of Phase I clinical studies with adjuvanted AKS-452 with the expectation that this room-temperature stable, Fc-fusion subunit vaccine can be rapidly and inexpensively manufactured to provide billions of doses per year especially in regions where the cold-chain is difficult to maintain.

A link between obesity, metabolic dysfunction, and an increased risk in cancer mortality has been well established in several cancer types including, breast, colon, pancreatic, and prostate cancers. A likely mechanism driving this elevated risk is the associated increase in circulating insulin and insulin-like growth factor (IGF), which are known promoters of cancer growth and have been linked to shorter progression-free survival, and increased risk of metastatic disease and death in breast cancer patients. IGF receptor (IGF1R) targeting has been unsuccessful as insulin receptor (IR) also is functional in breast cancers. To address IR targeting, Akston Biosciences developed a novel insulin-Fc fusion protein (AKS-130) with the goal of lowering patient blood glucose levels without causing clinical hypoglycemia. AKS-130 was also found to downregulate IR expression in models of colon cancer (HCT-116) and malignant melanoma (WM266.4). Further, AKS-130 suppressed xenograft growth in fed and fasted states. We examined if AKS-130 had similar effects on estrogen receptor (ER) positive breast cancer cells as ER+ breast cancers may have elevated expression or activation of IGF1R and IR. Data from our lab show that development of endocrine therapy resistance in ER+ breast cancer cell lines is associated with loss of IGF1R expression and subsequently increased sensitivity to insulin signaling, which supports overlapping pro-tumorigenic signaling pathways to IGF1R. To test the hypothesis that resistance to endocrine therapy increases the reliance of ER+ breast cancer cells on IR signaling, we used the ER+ breast cancer cell line, MCF-7L, and a Tam resistant derivative, MCF-7L TamR, to assess IR/IGF1R activation and growth in response to AKS-130. Similar to HCT-116 and WM266.4 cells, MCF-7L parental and TamR cells showed that AKS-130 was an agonist of IR. But after 72 hours of exposure, a marked reduction in IR was seen and associated with partially suppressed downstream signaling to Akt. Interestingly, AKS-130 induced proliferation at similar levels to insulin treatment in MCF-7L parental cells at three and five days post treatment. However, pre-treatment of cells with AKS-130 suppressed further insulin-stimulated growth in MCF-7L TamR cells. Ongoing studies are evaluating the effects of AKS-130 on ER+ breast cancer xenografts in vivo to determine if the ability of the drug to downregulate IR expression results in decreased tumor growth. Taken together these data show that novel agents, such as AKS-130, can target IR function in cancer cells. AKS-130 is a drug which may serve as way to disrupt IR in cancer cells without affecting host glucose metabolism. Targeting of IR signaling may represent a new strategy to overcome endocrine therapy resistance in breast cancer. Citation Format: Lynsey M Fettig, Xihong Zhang, Kelly LaPara, Sylaja Murikipudi, Andrea R Delpero, Thomas M Lancaster, Todd C Zion, Douglas Yee. A novel long-acting insulin for cancer therapy reduces xenograft tumor growth [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-21-05.

To address the coronavirus disease 2019 (COVID-19) pandemic caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a recombinant subunit vaccine, AKS-452, is being developed comprising an Fc fusion protein of the SARS-CoV-2 viral spike protein receptor binding domain (SP/RBD) antigen and human IgG1 Fc emulsified in the water-in-oil adjuvant, Montanide™ ISA 720. A single-center, open-label, phase I dose-finding and safety study was conducted with 60 healthy adults (18-65 years) receiving one or two doses 28 days apart of 22.5 µg, 45 µg, or 90 µg of AKS-452 (i.e., six cohorts, N = 10 subjects per cohort). Primary endpoints were safety and reactogenicity and secondary endpoints were immunogenicity assessments. No AEs ≥ 3, no SAEs attributable to AKS-452, and no SARS-CoV-2 viral infections occurred during the study. Seroconversion rates of anti-SARS-CoV-2 SP/RBD IgG titers in the 22.5, 45, and 90 µg cohorts at day 28 were 70%, 90%, and 100%, respectively, which all increased to 100% at day 56 (except 89% for the single-dose 22.5 µg cohort). All IgG titers were Th1-isotype skewed and efficiently bound mutant SP/RBD from several SARS-CoV-2 variants with strong neutralization potencies of live virus infection of cells (including alpha and delta variants). The favorable safety and immunogenicity profiles of this phase I study (ClinicalTrials.gov: NCT04681092) support phase II initiation of this room-temperature stable vaccine that can be rapidly and inexpensively manufactured to serve vaccination at a global scale without the need of a complex distribution or cold chain.

For the treatment of diabetes mellitus (DM) in dogs, novel insulins with decreased injection frequency while maintaining safety and efficacy are desirable. Insulin fused with immunoglobulin-fragment-crystallizable (Fc) has an ultra-long plasma half-life because it recycles through cells, protected from proteolysis.Glycemic control can be achieved in diabetic dogs with a recombinant fusion protein of a synthetic insulin and canine Fc (AKS-218d) administered subcutaneously once-weekly.Five client-owned dogs with naturally occurring DM.Prospective clinical trial in dogs with DM that were recruited from the UC Davis Veterinary Teaching Hospital and local veterinary clinics. Dogs previously controlled using intermediate-acting insulin q12h were transitioned to once-weekly injections of a preliminary construct identified as AKS-218d. The dose of AKS-218d was titrated weekly for 8 weeks based on clinical response and continuous interstitial glucose monitoring. Clinical signs, body weight, serum fructosamine concentrations, and mean interstitial glucose concentrations (IG) over the preceding week were compared between baseline (before AKS-218d) and during the last week of treatment. Data were compared using nonparametric paired tests.Once-weekly AKS-218d, compared to baseline twice-daily insulin therapy, resulted in no significant changes in clinical signs, median (range) body weight (+0.4 kg [-0.5-1.1]; P = .6), fructosamine concentration (-75 mmol/L [-215 to +126]; P = .4), or mean IG (+81 mg/dL [-282 to +144]; P = .8). No adverse reactions were reported.Control of clinical signs, body weight, and maintenance of glycemia was achieved with this once-weekly novel insulin construct in 4 of 5 dogs.

Obesity and metabolic dysfunction are on the rise in the United States. Hyperinsulinemia, frequently seen in these conditions, correlates with an increased risk of development and mortality from estrogen receptor (ER) positive breast cancer. Expression of components of the insulin and insulin-like growth factor (IGF) family of proteins promote cancer cell growth in vitro, link to shorter progression-free survival, and is associates with an increased risk of metastatic disease and death in breast cancer patients. Previously our lab found that development of resistance to the commonly used ER-targeting drug tamoxifen (Tam) in vitro is associated with a loss of the type I IGF receptor expression with an increased dependence on the homologous insulin receptor (IR). These data argue for targeting IR in breast cancer, but concern has been raised due to the potential of disrupting glucose homeostasis in patients with or without existing metabolic disease. To address this concern, a novel insulin-Fc fusion protein (AKS-130) was developed to lower blood glucose levels without causing clinical hypoglycemia with a potential to target tumor IR. AKS-130 was found to downregulate IR expression in models of colorectal cancer (HCT-116) and malignant melanoma (WM266.4). Further, AKS-130 suppressed xenograft growth in fed and fasted states. We examined if AKS-130 had similar effects on ER positive breast cancer cells. To test the hypothesis that resistance to endocrine therapy increases the reliance of ER positive breast cancer cells on IR signaling, we utilized the ER positive breast cancer cell lines (MCF-7L, T47D) and their Tam resistant derivatives (MCF-7L TamR, T47D TamR). Similar to in HCT-116 and WM266.4 cells, we found that AKS-130 is a modest agonist of IR in ER+ breast cancer cells. Exposure to AKS-130 led to a marked reduction in IR expression in both parental and TamR cell lines, and was associated with partially suppressed downstream signaling to Akt. Interestingly, AKS130 induced IR downregulation was inhibited by pretreatment of BMS 536924, a dual IGF1R/IR kinase inhibitor. In vivo, AKS-130 treatment by itself scaled down MCF7L parental xenograft growth as compared to vehicle group, and AKS-130 in combination with Tam trended toward extending time to a tumor size of 500mm3. In MCF7L TamR xenografts, addition of AKS-130 to Tam treatment also trended toward delaying xenograft growth, though it was not statistically significant. Importantly, prolonged treatment with AKS-130 did not lead to significant changes in weight or blood glucose. Taken together these data show that novel agents, such as AKS-130, may serve as way to disrupt IR signaling in cancer cells without affecting host glucose metabolism. Addition of AKS-130 to Tam treatment trended toward delaying xenograft growth though further studies are needed, especially animal model systems of insulin resistance. These data indicate that IR signaling may represent a target to overcome or delay endocrine therapy resistance in breast cancer. Citation Format: Jingran Cao, Lynsey M. Fettig, Kelly LaPara, Xihong Zhang, Sylaja Murikipudi, Andrea R. Delpero, Thomas M. Lancaster, Todd C. Zion, Douglas Yee. Targeting insulin receptor in estrogen receptor positive breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-02-01.

Partial or even complete cancer regression can be achieved in some patients with current cancer treatments. However, such initial responses are almost always followed by relapse, with the recurrent cancer being resistant to further treatments. The discovery of therapeutic approaches that counteract relapse is, therefore, essential for advancing cancer medicine. Cancer cells are extremely heterogeneous, even in each individual patient, in terms of their malignant potential, drug sensitivity, and their potential to metastasize and cause relapse. Indeed, hypermalignant cancer cells, termed cancer stem cells or stemness-high cancer cells, that are highly tumorigenic and metastatic have been isolated from cancer patients with a variety of tumor types. Moreover, such stemness-high cancer cells are resistant to conventional chemotherapy and radiation. Here we show that BBI608, a small molecule identified by its ability to inhibit gene transcription driven by Stat3 and cancer stemness properties, can inhibit stemness gene expression and block spherogenesis of or kill stemness-high cancer cells isolated from a variety of cancer types. Moreover, cancer relapse and metastasis were effectively blocked by BBI608 in mice. These data demonstrate targeting cancer stemness as a novel approach to develop the next generation of cancer therapeutics to suppress cancer relapse and metastasis.

Endothelial cells (EC) are potent bioregulatory cells, modulating thrombosis, inflammation and control over mural smooth muscle cells and vascular health. The biochemical roles of EC are retained when cells are embedded within three-dimensional (3D) denatured collagen matrices. Though substrate mechanics have long been known to affect cellular morphology and function and 3D-EC systems are increasingly used as therapeutic modalities little is known about the effect of substrate mechanics on EC in these 3D systems. In this work, we examined the effect of isolated changes in modulus on EC growth and morphology, extracellular matrix gene expression, modulation of smooth muscle cell growth, and immunogenicity. EC growth, but not morphology was dependent on scaffold modulus. Increased scaffold modulus reduced secretion of smooth muscle cell growth inhibiting heparan sulfate proteoglycans (HSPGs), but had no effect on secreted growth factors, resulting in a loss of smooth muscle cell growth inhibition by EC on high modulus scaffolds. Expression of ICAM-1, VCAM-1 and induction of CD4[superscript +] T cell proliferation was reduced by increased scaffold modulus, and correlated with changes in integrin α5 expression. Expression of several common ECM proteins by EC on stiffer substrates dropped, including collagen IV(α1), collagen IV(α5), fibronectin, HSPGs (perlecan and biglycan). In contrast, expression of elastin and TIMPs were increased. This work shows even modest changes in substrate modulus can have a significant impact on EC function in three-dimensional systems. The mechanism of these changes is not clear, but the data presented here within suggests a model wherein EC attempt to neutralize changes in environmental force balance by altering ECM and integrin expression, leading to changes in effects on downstream signaling and function., National Institutes of Health (U.S.) (R01 GM49039), Else Kroner-Fresenius Stiftung (P36/07//A45/07)

Background. Endothelial cells (ECs) embedded in 3D matrices [matrix-embedded endothelial cells (MEECs)] of denatured collagen implanted around vascular access anastomoses preserve luminal patency. MEEC implant efficacy depends on embedded EC health. As the uremic milieu inhibits proliferation and induces apoptosis of ECs, we examined whether uremia might impact MEECs. Methods. ECs grown on 2D gelatin-coated polystyrene tissue culture plates (gTCPS) or in MEEC were treated with sera pooled from 20 healthy control or uremic patients with end-stage renal disease. EC viability was examined using 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide assay, cell counting and Trypan blue exclusion. Media conditioned (CM) with 2 and 3D-supported ECs were examined for its potential to inhibit vascular smooth muscle cell (vSMC) proliferation using 3[H] thymidine incorporation and cyclin D1 expression. ECs grown on gTCPS were treated with uremic serum filtered through matrices to examine if matrices retain uremic toxins or whether EC effects were cell mediated. Results. Uremic serum significantly reduced viability and number of live, and increased dead ECs when grown on gTCPS, but not in MEECs. EC survival correlated with vSMC inhibition. While CM from ECs grown in gTCPS with uremic serum inhibited vSMC proliferation no better than uremic serum alone (22 versus 27%), MEEC CM inhibited vSMC proliferation by 47% (P = 0.0004). Cyclin D1 expression tracked with indices of vSMC proliferation. There was no significant difference in EC viability between EC treated with matrix-filtered or unfiltered uremic serum. Conclusion. The viability, number and efficacy of MEECs were preserved in uremic serum compared to those of ECs on gTCPS. MEECs are protected from uremic toxicity, not from retention of uremic toxins by matrices, but likely from intrinsic changes in EC sensitivity to uremia. MEECs implanted at vascular access sites should inhibit neointimal hyperplasia in uremia. This study underscores the robustness of matrix embedding as a cell protectant, especially in hostile environments like uremia.

Cancer cells are extremely heterogeneous, even in each individual patient, in terms of their malignant potential, drug-senstivity, and their potential to metastasize and cause relapse. Subpopulations of cancer cells with extremely high tumorigenic potential have been isolated from cancer patients with a variety of tumor types and found to have high stemness properties termed cancer stem cells. These stemness-high cancer cells are extremely tumorigenic and are resistant to conventional therapeutics due to activation of pro-survival and anti-apoptotic pathways, overexpression of drug efflux pumps, and increased DNA repair capacity. Moreover, chemotherapy and radiation have been found to induce stemness genes in cancer cells, converting stemness-low cancer cells to stemness-high cancer cells. Such highly tumorigenic and drug-resistant stemness-high cancer stem cells are, therefore, likely to be “left-over” following chemotherapy or radiotherapy and ultimately responsible for relapse. We hypothesized that cancer stemness inhibition is sufficient to suppress metastasis and relapse. Stemness, initially defined by the expression of stem cells genes, is a property shared by embryonic stem cells and adult stem cells. It has been demonstrated that the gene expression profiles of cancer stem cells more closely resemble embryonic stem cells than adult stem cells, suggesting the feasibility to identify molecular targets that are required for cancer stemness, but not (or less so) by normal adult stem cells. Through gene-silencing approaches, we have identified Stat3 as critically important for maintaining cancer stemness, yet largely dispensable for adult stem cells. Here we show that BBI608, a small molecule identified by its ability to inhibit gene-transcription driven by Stat3 and cancer cell stemness properties, displays anticancer properties that are highly different from chemotherapeutics agents. Stemness-high cancer cells enriched by multiple techniques are resistance to chemotherapeutics, yet highly sensitive to the stemness inhibitor BBI608. Blockade of spherogenesis and reduction of stemness gene expression by BBI608 were observed in stemness-high cancer cells isolated from a variety of cancer types. While treatment of xenografted tumor models with chemotherapeutics enriched stemness-high cancer cells, BBI608 induced significant depletion of stemness-high populations in vivo. Moreover, the inhibition of stemness by BBI608 is sufficient to suppress cancer relapse and metastasis in xenografted human cancers in mice. These data demonstrate targeting cancer stemness as an effective way to suppress cancer relapse and metastasis. Citation Format: Youzhi Li, Harry A. Rogoff, Sarah Keates, Yuan Gao, Sylaja Murikipudi, Keith Mikule, David Leggett, Wei Li, Arthur Pardee, Chiang J. Li. Inhibition of stemness by BBI608 is sufficient to suppress cancer relapse and metastasis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-253. doi:10.1158/1538-7445.AM2015-LB-253