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Figure S1 shows the gating strategy for PMN apoptosis analysis, RT-PCR, immunofluorescence staining, and flow cytometry analyses of FPR2/ALX-transfected HEK cells, effect of NAP1051 on dTHP-1 cells with selective kinase inhibitors, and Western blot with normal HEK cells and FPR2/ALX-transfected HEK cells

Table S1 lists flow cytometry antibodies and panel design. Table S2 lists primers for RT-PCR analyses. Table S3 includes antibodies for immunohistochemistry and immunofluorescent staining.

Resolving tumor-associated inflammation in the tumor microenvironment (TME) may promote antitumor effects. Lipoxin A4 (LXA4) is a short-lived endogenous bioactive lipid with potent anti-inflammatory and pro-resolving properties. Here, a biomimetic of LXA4, NAP1051, was shown to have LXA4-like in vitro properties and antitumor activity in colorectal cancer xenograft models. NAP1051 inhibited neutrophil chemotaxis toward fMLP and dose-dependently promoted dTHP-1 efferocytosis which was equipotent to aspirin-triggered lipoxin A4 (ATLA). In dTHP-1 cells, NAP1051 induced strong phosphorylation on ERK1/2 and AKT similar to formyl peptide receptor 2 (FPR2/ALX) agonists. In two mouse xenograft colorectal cancer models, NAP1051 significantly inhibited tumor growth when given orally at 4.8 to 5 mg/kg/day. Flow cytometric analyses showed that NAP1051 reduced splenic and intratumoral neutrophil and myeloid-derived suppressor cell populations, which correlated to the antitumor effect. In addition, NAP1051 reduced NETosis in the TME while stimulating T-cell recruitment. Overall, these results show that NAP1051 possesses key lipoxin-like properties and has antitumor activity against colorectal cancer via modulation of neutrophils and NETosis in the TME.

Purpose: Resolving tumor-associated inflammation in the tumor microenvironment (TME) can restore the immune response against malignant tissue. Lipoxin A4 (LXA4) is a short-lived endogenous bioactive lipid with potent anti-inflammatory and pro-resolving properties. We developed a LXA4 biomimetic, NAP1051, with increased stability and longer half-life, and demonstrated its properties using in vitro assays and in vivo xenograft tumor models and explored the underlying mechanism of action (MoA). Methods: Differentiated HL-60 and THP-1 induced by DMSO and PMA, respectively, were used as models. dHL-60 was used to determine the effect of NAP1051 on fMLP-induced neutrophil chemotaxis. NAP1051-induced dTHP-1 efferocytosis of apoptotic dHL-60 was measured using fluorescent microscopy. Concentration escalation and time of NAP1051 exposure were used to probe the molecular mechanism using Western Blot and RT-PCR. The efficacy of oral NAP1051 was evaluated in CT26 (CRC) xenograft model established in immunocompetent Balb/c mice with a dosage escalation design. Results: NAP1051 inhibited neutrophil chemotaxis towards fMLP by > 40% at 1, 10 and 100 nM (p < 0.05). NAP1051 dose-dependently promoted dTHP-1 efferocytosis (p < 0.05) and was equipotent to ATLA4. In dTHP-1 cells, NAP1051 induced strong phosphorylation on ERK1/2 and AKT from 10 nM to 1 µM. When compared to ATLA4 and W-peptide, NAP1051 caused strong phosphorylation at both S473 and T308 of AKT. The NAP1051-induced p-ERK1/2 and p-AKT were in parallel and in a dose-dependent and time-dependent way. MoA studies revealed that such p-ERK1/2 was mediated by MEK1/2. However, NAP1051 led to p-AKT at both S473 and T308 despite PI3K inhibition, indicating a PI3K-independent pathway was involved. In the mouse xenograft CRC model, we demonstrated that NAP1051 significantly inhibit tumor growth when given p.o. at 5 mg/kg/day. Flow cytometry on splenic cells showed that NAP1051 reduced splenic neutrophil and MDSC populations, which correlated to the tumor sizes. IHC analyses revealed that NAP1051 decreased the intratumoral Ly6G+ neutrophils most significantly at 5 mg/kg/day (p Conclusions: NAP1051 has LXA4-like activity including inhibiting fMLP-mediated neutrophil chemotaxis and promoting macrophage efferocytosis of apoptotic cells. The molecular MoA of NAP1051 involves ERK1/2 and AKT signaling pathways which are interrelated closely. A PI3K-independent pathway may be activated and resulted in AKT activation. NAP1051 inhibited tumor growth significantly at 5 mg/kg/day in a CRC model with significant changes in splenic and intratumoral immune cell populations. With these properties, NAP1051 may be an effective component in the treatment of CRCs by modulating the inflammatory immune cells in the TME. Citation Format: Tiange Dong, Priyal Dave, Brandon Ebright, Kabir Ahluwalia, Eugene Zhou, Isaac Asante, Malika Salimova, Hua Pei, Tracey Lin, Andrew Mead, Zeyang Li, Nicos Petasis, Stan Louie. Mechanistic investigation of NAP1051, a lipoxin A4 biomimetic, in treating colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1436.

Background: Cancer survival is dependent on the increase of protein synthesis for cell migration, proliferation and metastasis. Cancer adaptive mechanisms include upregulation of endoplasmic reticulum (ER) activities to accommodate increases in misfolded proteins. Sarcoendoplasmic reticulum calcium ATPase (SERCA) are important regulators of calcium found in the endoplasmic reticulum, where inhibition can lead to protein misfolding. Since breast cancer cells express higher level of SERCA2, its overexpression maybe a target for drug development. Method: Using an in vitro screening method to guide our development, we have developed a pharmacophore and made structural changes to enhance anti-cancer activity while reducing of COX-2 inhibition. In this effort, we have identified C1, a coxib analogue with improved antitumor activities with minimal COX-2 inhibitory properties. We have further tested C1 in nu/nu athymic mice xenograft with human breast cancer cell line (MDA MB 231). Tumor volume and animal weights were measured three times a week for 28 days. At the end of the study, tumor volume was correlated with molecular markers using RT-PCR and IHC staining. Results: Our screening identified C1 as a promising anti-cancer compound in vitro and affirmed in xenograft triple negative breast cancer (TNBC) animal model. C1 has EC50 of 85% tumor reduction when compared to vehicle after 28 days of treatment. The safety of C1 was assessed for 48 days at 100 mg/kg/day, where no detectable biochemical, hematologic or histological toxicities were detected. RT-PCR analysis of residual tumor correlated with cell death indicated through the activation of CHOP and DR5 marker. Finally, C1 treatment also decreased angiogenesis markers VEGF-α and IL-8, corresponding to reduction in microvessel formation. Conclusion: C1 is a bioavailable coxib analogue with minimal COX-2 inhibition while possessing broad spectrum antitumor activity, including TNBC. Treatment with C1 leads to dosage dependent antitumor properties as a consequence of specific SERCA2 inhibition. In dosage escalation studies up to 100 mg/kg/day, no detectable biochemical and histological toxicities were detected. With these properties, C1 may be an effective component in the treatment of TNBCs, where effective therapy(ies) is much needed. Citation Format: Tracey J. Lin1, Julie Yoo2, Priyal Dave, Andrew Mead, Kabir Ahluwalia, Tiange Dong, Eugene Zhou, Hua Pei, Isaac Asante, Nicos Petasis, Stan Louie Citation Format: Tracey Lin, Julie Yoo, Priyal Dave, Andrew Mead, Kabir Ahluwalia, Tiange Dong, Eugene Zhou, Hua Pei, Isaac Asante, Nicos Petasis, Stan Louie. Oral administration of novel compound targeting triple negative breast cancer (TNBC) through the inhibition of SERCA2 [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4172.