Albumin-bound Nanoparticle Research Articles

Abstract 7196: Evaluation of nab-sirolimus in combination with fulvestrant or PI3K pathway inhibitors to overcome resistance in breast cancer cell lines

Abstract Background: Endocrine therapy (ET) is the standard of care for hormone receptor positive (HR+) breast cancer (BC), but ET resistance develops in most patients (pts). One resistance mechanism involves cross talk between the PI3K-AKT-mTOR and estrogen receptor (ER) signaling pathways, resulting in increased ER signaling and tumor proliferation. This is mitigated by mTOR inhibition as demonstrated by improved outcomes with exemestane plus the mTOR inhibitor (mTORi) everolimus in pts with HR+ advanced BC. While PI3K inhibitors (PI3Ki [e.g. alpelisib]) are efficacious in pts with HR+, PIK3CA-mutated BC, resistance can occur due to acquired genomic alterations in the PI3K-AKT-mTOR pathway. Combination therapy that targets a critical downstream node, mTOR, could delay or overcome acquired resistance due to activation of upstream components of the PI3K-AKT-mTOR pathway. nab-Sirolimus is an intravenously administered, albumin-bound nanoparticle form of the mTORi sirolimus, with significantly greater tumor accumulation, mTOR target suppression, and improved antitumor effects than oral mTORis in nonclinical tumor models. We evaluated the antiproliferative and cytotoxic effects of nab-sirolimus in combination with ET or PI3Kis in BC cell lines. Methods: HR+, PI3K-mutated BC cell lines (MCF7 or MDA-MB-361) were incubated for 5 days with increasing concentrations of nab-sirolimus and the selective ER degrader fulvestrant. MDA-MB-361 cells or HR-negative (HR−), PI3K-mutated BC cells, MDA-MD-453, were incubated for 5 days with increasing concentrations of nab-sirolimus and PI3K-AKT-mTOR pathway inhibitors gedatolisib or alpelisib. Antiproliferative/cytotoxic effects of single-agent and combination treatment were assessed via an automated trypan blue exclusion assay. Results: Addition of 20 or 80 nM nab-sirolimus to fulvestrant (12.5-500 nM) markedly decreased cell viability and nearly doubled cell death in MCF7 and MDA-MB-361 cells. Antiproliferative effects of low-dose gedatolisib (2.5-10 nM) were enhanced by 61-71% when nab-sirolimus (20 or 80 nM) was added to MDA-MB-453 cells. While low doses (2.5, 5, and 10 nM) of gedatolisib alone led to limited cytotoxicity (4.2-9.6%), up to 48.9% of cell death occurred when 20 or 80 nM nab-sirolimus was added. Results were similar with alpelisib (1 uM) plus nab-sirolimus (20 or 80 nM). Western blot showed increased p4EBP1 in response to fulvestrant or PI3Ki treatment, which was reversed with the addition of nab-sirolimus. Conclusions: nab-Sirolimus enhanced the cytotoxic effects of fulvestrant in HR+ BC cells and of PI3Kis in HR+ and HR− BC cells. Addition of nab-sirolimus to ET or other PI3K-AKT-mTOR pathway inhibitors may overcome mechanisms of resistance; further exploration is warranted to elucidate clinical relevance. Citation Format: Khine Nyein Myint, Sean Wallace, Shihe Hou, Maria Zalath, Brian McMorran, Andrew Kwon, Igor Vivanco. Evaluation of nab-sirolimus in combination with fulvestrant or PI3K pathway inhibitors to overcome resistance in breast cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7196.

Abstract B010: Response to treatment with nab-sirolimus among patients with primary uterine tumors: A subgroup analysis from AMPECT

Abstract Introduction/objective: AMPECT (NCT02494570) is a pivotal study of nab-sirolimus in patients with malignant perivascular epithelioid cell tumors (PEComa). Malignant PEComa is an aggressive, rare sarcoma for which cytotoxic chemotherapies provide limited patient benefit. Inactivation of TSC1 or TSC2 tumor suppressor genes, upstream of mTORC1, is commonly associated with malignant PEComa; these mutations occurred in 56% of patients in AMPECT. nab-Sirolimus is an mTOR inhibitor (mTORi) that utilizes albumin-bound nanoparticle technology to drive higher intratumoral drug levels and more complete pathway suppression than conventional mTORis. nab-Sirolimus is approved in the USA for the treatment of advanced or metastatic malignant PEComa based on the primary analysis results of the AMPECT trial, which showed a confirmed overall response rate (ORR) of 39%, regardless of mutation status. We describe outcomes of a subset of patients with primary uterine PEComa, representing 23% of efficacy-evaluable patients in AMPECT. Methods: AMPECT was an open-label, multicenter, phase 2 registration study in mTORi-naïve adult patients (≥18 years old) with a histologically confirmed diagnosis of malignant PEComa and Eastern Cooperative Oncology Group performance status score ≤1. Patients received nab-sirolimus 100 mg/m2 intravenously on days 1 and 8 of a 21-day cycle until progression or unacceptable toxicity. The primary endpoint was ORR by independent radiology review. Key secondary endpoints included time to response, duration of response (DOR), and safety. Results: A total of 7 patients with uterine PEComa were treated with nab-sirolimus in AMPECT and were evaluable for both safety and efficacy. Mean ± SD age was 60.0 ± 13.4 years, and 71% (5/7) of patients were White. ORR was 43% (3/7 patients); all 3 were confirmed partial responses and were seen in patients with tumors with somatic inactivating alterations in TSC1 or TSC2. Two (29%) patients had best response of stable disease. For the 3 responders, time to response was 1.4, 1.4, and 1.5 months, and DOR was 5.6, 36.0+, and 39.7 months. All 7 patients had ≥1 treatment-related adverse event (TRAE; grade 3, 43%); no grade ≥4 or serious TRAEs occurred. Conclusions: Rates of response to treatment and safety findings in patients with primary uterine PEComa treated with nab-sirolimus in AMPECT were consistent with those previously reported in the overall patient population. Responses were rapid and durable. Notably, all responders had TSC1 or TSC2 alterations; however, there were too few patients in this subset to draw conclusions regarding efficacy in tumors without these alterations. nab-Sirolimus is being further evaluated in a tumor-agnostic trial of patients with TSC1 or TSC2 inactivating alterations (PRECISION I; NCT05103358). Citation Format: Vinod Ravi, Mark A. Dickson, Kristin Ganjoo, Li Ding, Anita N. Schmid, Norma A. Palma, Willis H. Navarro, Andrew J. Wagner. Response to treatment with nab-sirolimus among patients with primary uterine tumors: A subgroup analysis from AMPECT [abstract]. In: Proceedings of the AACR Special Conference on Endometrial Cancer: Transforming Care through Science; 2023 Nov 16-18; Boston, Massachusetts. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(5_Suppl):Abstract nr B010.

Abstract A117: Evaluation of nab-sirolimus in combination with PI3K pathway inhibitors to overcome PI3K/mTOR resistance in PI3K-mutant breast cancer cell lines

Abstract Background: The PI3K-AKT-mTOR pathway is frequently activated in many cancer types and plays a central role in tumorigenesis. However, clinical use of therapies targeting this pathway is limited by compensatory vertical and horizontal feedback activation loops, which limit antitumor efficacy and lead to drug resistance. Combination therapy strategies employing simultaneous inhibition of multiple PI3K-AKT-mTOR pathway elements may overcome these resistance mechanisms and improve antitumor activity. nab-Sirolimus is a novel albumin-bound nanoparticle form of the mTOR inhibitor sirolimus that has significantly greater tumor accumulation, mTOR target suppression, and improved antitumor effects compared with conventional first generation mTOR inhibitors in preclinical models. Here, we analyzed the effects of nab-sirolimus combinations in PI3K-mutant breast cancer (BrCa) cells. Methods: PI3K mutated BrCa cell lines (MDA-MD-453, hormone receptor [HR]-; and MDA-MB-361, HR+) were incubated for 5 days with increasing concentrations of nab-sirolimus, the PI3K pathway inhibitors gedatolisib and alpelisib, or the AKT inhibitors miransertinib and capivasertib. The antiproliferative and cytotoxic effects of single agent and combination treatment were assessed using cell viability and cell death assays. Cell signaling was analyzed by western blot. Results: The antiproliferative effects of gedatolisib at low doses (2.5-10 nM) were enhanced by 61-71% in combination with nab-sirolimus (20 or 80 nM) in MDA-MB-453 cells. Limited cell death (4.2-9.6%) was observed in HR- MDA-MB-453 cells with low doses (2.5, 5, and 10 nM) of gedatolisib alone. In contrast, and despite the well-established cytostatic action of mTOR inhibitors, the addition of 20 and 80 nM nab-sirolimus led to high levels of cell death (up to 48.9%). Similar results were observed with alpelisib at 1 µM in combination with nab-sirolimus (20 or 80 nM), and also with capivasertib (1 µM) or miransertib (250 nM) combined with 80 nM nab-sirolimus. Western blot analysis demonstrated that gedatolisib or alpelisib alone each triggered upregulation of p4EBP1 whereas nab-sirolimus treatment alone activated a negative feedback loop through increased pAKT. Importantly, these compensatory feedback activation loops were both reversed by the combination of PI3K inhibitors and nab-sirolimus. Similar cell death and cell viability results were observed with nab-sirolimus plus PI3K inhibitors (gedatolisib or alpelisib) and AKT inhibitors (capivasertib or miransertib) in HR+ MDA-MB-361 cells. Conclusions: The antitumor effects of PI3K and AKT inhibitors were enhanced by the addition of the novel mTOR inhibitor nab-sirolimus. The improved effectiveness of the PI3K and mTOR inhibitor combination was due to the reciprocal overcoming of resistance mechanisms induced by single agent treatment. These data support a vertical PI3K pathway inhibition strategy using nab-sirolimus and PI3K/AKT inhibitors in PIK3CA-mutated BrCa, regardless of HR status. Citation Format: Sean Wallace, Khine Nyein Myint, Shihe Hou, Maria Zalath, Andrew Kwon, Brian McMorran, Igor Vivanco. Evaluation of nab-sirolimus in combination with PI3K pathway inhibitors to overcome PI3K/mTOR resistance in PI3K-mutant breast cancer cell lines [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A117.

Abstract 5484: Synergistic antitumor activity of nab-sirolimus in combination with KRAS inhibitors (KRASis) sotorasib and adagrasib in KRAS G12C NSCLC and bladder cancer xenografts

Abstract KRAS is frequently mutated in non-small cell lung cancer (NSCLC) and other tumor types, with KRAS G12C mutation representing ~12% of patients with NSCLC. Sotorasib (sot) is approved and adagrasib (ada) is under review for the treatment of KRAS G12C NSCLC. Mutations in KRAS may lead to mTORC1 activation, and mTOR may contribute to adaptive resistance to KRASis. nab-Sirolimus (nab-S) is a novel albumin-bound nanoparticle form of the mTOR inhibitor sirolimus approved for the treatment of locally advanced unresectable or metastatic malignant perivascular epithelioid cell tumors. This study investigated the antitumor activity of nab-s in combination with KRASis in KRAS G12C NSCLC and bladder xenograft models. Athymic mice bearing subcutaneous KRAS G12C- and STK11-mutant NCI-H2030 and NCI-H2122 NSCLC and KRAS G12C and PTEN-null UMUC3 bladder cancer were treated for 6 weeks with nab-s IV at 15 mg/kg/wk, sot or ada (for NCI-H2122 and UMUC3) orally at 30 mg/kg/d alone or in combination. Tumor samples were harvested for analysis of tumor drug levels and biomarkers. In all 3 models tested, single-agent (SA) nab-s or KRASis overall showed modest tumor growth suppression. In contrast, nab-s in combination with either sot or ada showed greater tumor growth inhibition and a higher meaningful tumor regression rate vs SA (Table). There was no significant difference in antitumor activity between combinations of nab-s with either sot or ada. High trough intertumoral sirolimus levels were observed in groups treated with nab-s alone or in combination with KRASis, indicating sustained presence of sirolimus in the tumor. nab-S in combination with either sot or ada showed synergistic antitumor activity compared to the SA. A multicenter, single-arm, open-label Phase 1/2 clinical study is planned to determine the recommended Phase 2 dose, safety, tolerability, and efficacy for the combination of ada and nab-s in patients with KRAS G12C tumors. Changes in TGI and Tumor Regression Tumor Model Combination Treatment TGI vs Single Agent (%) P Value vs Single Agent for Tumor Growth Curve (ANOVA) Tumor Regression Over 30% P Value vs Single Agents for Rate of Tumor Regression Over 30% (Chi-Square) vs nab-S vs KRASi vs nab-S vs KRASi NCI-H2030 nab-S + Sotorasib 129 111 0.01 0.001 3/6 0.03 NCI-H2122 nab-S + Sotorasib 112 106 0.001 <0.001 8/10 <0.001 nab-S + Adagrasib 101 100 0.001 <0.001 4/10 0.03 UMUC3 nab-S + Sotorasib 107 105 <0.001 <0.001 6/6 <0.001 nab-S + Adagrasib 107 107 <0.001 0.04 6/6 0.001 ANOVA, analysis of variance; KRASi, KRAS inhibitor; nab-s, nab-sirolimus; TGI, tumor growth inhibition. Citation Format: Shihe Hou, Andrew Kwon, Jorge Nieva, Neil Desai. Synergistic antitumor activity of nab-sirolimus in combination with KRAS inhibitors (KRASis) sotorasib and adagrasib in KRAS G12C NSCLC and bladder cancer xenografts. [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 5484.

Intravital Microscopy Reveals Endothelial Transcytosis Contributing to Significant Tumor Accumulation of Albumin Nanoparticles.

The principle of enhanced permeability and retention (EPR) effect has been used to design anti-cancer nanomedicines over decades. However, it is being challenged due to the poor clinical outcome of nanoparticles and controversial physiological foundation. Herein, we use a near-infrared-II (1000-1700 nm, NIR-II) fluorescence probe BPBBT to investigate the pathway for the entry of human serum albumin-bound nanoparticles (BPBBT-HSA NPs) into tumor compared with BPBBT micelles with phospholipid-poly (ethylene glycol) of the similar particle size about 110 nm. The plasma elimination half-life of BPBBT micelles was 2.8-fold of that of BPBBT-HSA NPs. However, the area under the BPBBT concentration in tumor-time curve to 48 h post-injection (AUCtumor0→48h) of BPBBT-HSA NPs was 7.2-fold of that of BPBBT micelles. The intravital NIR-II fluorescence microscopy revealed that BPBBT-HSA NPs but not BPBBT micelles were transported from the tumor vasculature into tumor parenchyma with high efficiency, and endocytosed by the tumor cells within 3 h post-injection in vivo. This effect was blocked by cross-linking BPBBT-HSA NPs to denature HSA, resulting in the AUCtumor0→48h decreased to 22% of that of BPBBT-HSA NPs. Our results demonstrated that the active process of endothelial transcytosis is the dominant pathway for albumin-bound nanoparticles' entry into tumor.

A Phase I/II Study of Necitumumab Plus Pembrolizumab, Nab-Paclitaxel, and Carboplatin for Previously Untreated Advanced Squamous Non–Small Cell Lung Cancer Study: (NEJ048A/NEXUS)

BackgroundPlatinum-based combination therapy plus a programmed cell death 1/programmed cell death ligand 1 (PD-1/PD-L1) inhibitor is a standard treatment for patients with stage IV non–small cell lung cancer. However, necitumumab is used with gemcitabine and cisplatin as a first-line treatment option for squamous cell lung cancer (SqCLC). Furthermore, the combination of necitumumab with immune checkpoint inhibitors has the potential to enhance tumor immunity and improve the therapeutic effect. Thus, we planned and initiated this phase I/II study to evaluate the safety and efficacy of necitumumab plus pembrolizumab, nanoparticle albumin–bound (nab)-paclitaxel), and carboplatin therapy for patients with previously untreated SqCLC. Patients and MethodsIn phase I, the primary endpoint is the tolerability and recommended dose of necitumumab combined with pembrolizumab plus nab-paclitaxel and carboplatin. In phase II, the primary endpoint is the overall response rate. Secondary endpoints are disease control rate, progression-free survival, overall survival, and safety. Forty-two patients will be enrolled in phase II. ConclusionThis is the first study to investigate the efficacy and safety of necitumumab plus pembrolizumab combined with platinum-based chemotherapy in patients with previously untreated SqCLC.

Assessment of superiority of HSP70-targeting aptamer-functionalized drug-nanocarrier over non-targeted commercially available counterpart in HCC therapy: in vitro and in vivo investigations and molecular modeling

AimsThis research aims to compare the therapeutic potential of target-specific phosphorothioate backbone-modified aptamer L5 (TLS9a)-functionalized paclitaxel (PTX)-loaded nanocarrier (PTX-NPL5) that we formulated with that of non-targeted commercial formulation, protein albumin-bound nanoparticles of PTX, Abraxane® (CF) against hepatocellular carcinoma (HCC) through a myriad of preclinical investigations. Main methodsA variety of in vitro and in vivo assays have been executed to compare the therapeutic effects of the formulations under investigation, including the investigation of the degree of apoptosis induction and its mechanism, cell cycle analysis, the level of ROS production, and redox status, the morphological and histological characteristics of malignant livers, and in vivo imaging. The formulations were also compared concerning pharmacokinetic behaviors. Finally, in silico molecular docking has been performed to predict the possible interactions between aptamer and target(s). Key findingsPTX-NPL5 exhibited therapeutic superiority over CF in terms of inducing apoptosis, cell cycle arrest, endorsing oxidative stress to neoplastic cells, and reducing hepatic cancerous lesions. Unlike CF, PTX-NPL5 did not exhibit any significant toxicity in healthy hepatocytes, proving enough impetus regarding the distinctive superiority of PTX-NPL5 over CF. The pharmacokinetic analysis further supported superior penetration and retention of PTX-NPL5 in neoplastic hepatocytes compared to CF. A molecular modeling study proposed possible interaction between aptamer L5 and heat shock protein 70 (HSP70). SignificanceThe target-specificity of PTX-NPL5 towards neoplastic hepatocytes, probably achieved through HSP70 recognition, enhanced its therapeutic efficacy over CF, which may facilitate its real clinical deployment against HCC in the near future.

Successful second conversion surgery after trastuzumab deruxtecan for recurrent HER2-positive gastric cancer.

A 65-year-old woman with HER2-positive gastric cancer with multiple liver metastases underwent first conversion surgery of gastrectomy with D2 lymph nodes dissection and three liver metastases after combination therapy with capecitabine, cisplatin, and trastuzumab. Two years later, she experienced multiple liver metastases that were refractory to combination therapy with paclitaxel albumin-bound nanoparticles and ramucirumab. She participated in the DESTINY-Gastric01 trial and received tri-weekly trastuzumab deruxtecan as third-line treatment for 26 cycles. The recurrent lesions markedly shrank, and this effect continued for 19months. We then performed partial hepatectomy for the one remaining lesion. No adjuvant chemotherapy was given, and she remains alive without recurrence 18months after the second conversion surgery. Trastuzumab deruxtecan may generate a notable tumor response and subsequent conversion surgery could be a treatment option for HER2-positive stage IV gastric cancer.

Preparation and Characterization of Bovine Serum Albumin Nanoparticles of Curcumin using a Chemometric Approach

Bovine Serum Albumin (BSA) has been presupposed to be a versatile protein polymer for targeted drug delivery. BSA nanoparticles can lead to passive targeting of drugs to the inflamed joint via the Enhanced Permeability and Retention (EPR) effect and due to their specific affinity towards the inflamed joint because of the inadequacy of protein in the affected region. Hence, the aim of the study was to develop BSA nanoparticles loading curcumin (BSA_CUR_NPs) by nanoparticle albuminbound technology and its optimization was conducted by 33 Box Behnken Design (BBD) in order to achieve the desired particle size and entrapment efficiency. Further, the optimised nanoparticles were also assessed for polydispersity index, zeta potential, total drug content, and in-vitro drug release study. The response surface plots and equations generated by BBD predicted the relationship between variables under study. The optimised formulation C12 was found to have a particle size of 207.1 ± 1.36nm, PDI of 0.138 ± 0.03, entrapment efficiency of 75.04 ± 0.06 %, total drug content of 91.40 ± 0.08% and zeta potential of -32.9mV. The optimised nanoparticles exhibited good sustained release for up to 8 days. The use of a chemometric approach led to the development of BSA_CUR_NPs with the desired characteristics with a less experimental procedure. Therefore, it presents an important model for producing the nanoparticles of the desired characteristics using albumin as a polymer for the enhanced and sustained delivery of loaded drugs to the inflamed joint.

Recent Developments and Anticancer Therapeutics of Paclitaxel: An Update.

Plants are a source of diverse classes of secondary metabolites with anticancer properties. Paclitaxel (Taxol) is an anticancer drug isolated from various Taxus species and is used as a chemotherapeutic agent against various cancers. The biosynthesis of paclitaxel is a complex pathway, making its total chemical synthesis commercially non-viable; hence, alternative novel sources - like plant cell culture and heterologous expression systems, are being investigated to overcome this issue. Advancements in the field of genetic engineering, microbial fermentation engineering, and recombinant techniques have significantly increased the achievable yields of paclitaxel. Indeed, paclitaxel selectively targets microtubules and causes cell cycle arrest in the G2/M phase, inducing a cytotoxic effect in a concentration and time-dependent manner. Innovative drug delivery formulations, like the development of albumin-bound nanoparticles, nano-emulsions, nano-suspensions, liposomes, and polymeric micelles, have been applied to enhance the delivery of paclitaxel to tumor cells. This review focuses on the production, biosynthesis, mechanism of action, and anticancer effects of paclitaxel.

163 (PB043) - KRAS G12C mutated NSCLC and bladder cancer xenografts treated with sotorasib and adagrasib in combination with mTOR inhibitors show improved antitumor activity of nab-sirolimus vs everolimus

Background: KRAS is frequently mutated in non-small cell lung cancer (NSCLC) and other tumor types, with KRAS G12C mutation representing ∼9% of NSCLC patients. mTOR pathway is often activated in patients with KRAS mutation and contributes to adaptive resistance to KRAS inhibitors. A combination of mTOR and KRAS inhibitors may mitigate resistance. nab-Sirolimus is a novel albumin-bound nanoparticle form of mTOR inhibitor sirolimus and is approved for the treatment of locally advanced unresectable or metastatic malignant perivascular epithelioid cell tumor (PEComa).

Pharmacokinetic behaviors of soft nanoparticulate formulations of chemotherapeutics.

Chemotherapeutic treatment with conventional drug formulations pose numerous challenges, such as poor solubility, high cytotoxicity and serious off-target side effects, low bioavailability, and ultimately subtherapeutic tumoral concentration leading to poor therapeutic outcomes. In the field of Nanomedicine, advances in nanotechnology have been applied with great success to design and develop novel nanoparticle-based formulations for the treatment of various types of cancer. The approval of the first nanomedicine, Doxil® (liposomal doxorubicin) in 1995, paved the path for further development for various types of novel delivery platforms. Several different types of nanoparticles, especially organic (soft) nanoparticles (liposomes, polymeric micelles, and albumin-bound nanoparticles), have been developed and approved for several anticancer drugs. Nanoparticulate drug delivery platformhave facilitated to overcome of these challenges and offered key advantages of improved bioavailability, higher intra-tumoral concentration of the drug, reduced toxicity, and improved efficacy. This review introduces various commonly used nanoparticulate systems in biomedical research and their pharmacokinetic (PK) attributes, then focuses on the various physicochemical and physiological factors affecting the in vivo disposition of chemotherapeutic agents encapsulated in nanoparticles in recent years. Further, it provides a review of the current landscape of soft nanoparticulate formulations for the two most widely investigated anticancer drugs, paclitaxel, and doxorubicin, that are either approved or under investigation. Formulation details, PK profiles, and therapeutic outcomes of these novel strategies have been discussed individually and in comparison, to traditional formulations. This article is categorized under: Nanotechnology Approaches to Biology > Cells at the Nanoscale Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

The Neonatal Fc Receptor Is Elevated in Monocyte-Derived Immune Cells in Pancreatic Cancer.

The neonatal Fc receptor (FcRn) is responsible for recycling of IgG antibodies and albumin throughout the body. This mechanism has been exploited for pharmaceutic delivery across an array of diseases to either enhance or diminish this function. Monoclonal antibodies and albumin-bound nanoparticles are examples of FcRn-dependent anti-cancer therapeutics. Despite its importance in drug delivery, little is known about FcRn expression in circulating immune cells. Through time-of-flight mass cytometry (CyTOF) we were able to characterize FcRn expression in peripheral blood mononuclear cell (PBMC) populations of pancreatic ductal adenocarcinoma (PDAC) patients and non-cancer donors. Furthermore, we were able to replicate these findings in an orthotopic murine model of PDAC. Altogether, we found that in both patients and mice with PDAC, FcRn was elevated in migratory and resident classical dendritic cell type 2 (cDC2) as well as monocytic and granulocytic myeloid-derived suppressor cell (MDSC) populations compared to tumor-free controls. Furthermore, PBMCs from PDAC patients had elevated monocyte, dendritic cells and MDSCs relative to non-cancer donor PBMCs. Future investigations into FcRn activity may further elucidate possible mechanisms of poor efficacy of antibody immunotherapies in patients with PDAC.

Abstract 245: Interleukin-4 receptor-targeted Abraxane inhibits tumor growth by enhancing drug delivery and reprogramming of M2-type macrophages into M1 phenotype

Abstract Abraxane, an albumin-bound paclitaxel nanoparticle, is widely used in treating patients with cancer such as breast cancer. The present study aims at a targeted delivery of Abraxane to tumors by conjugating it with IL4RPep-1, an interleukin-4 receptor (IL4R)-binding peptide. IL4R is up-regulated in many tumor cells and M2-polarized macrophages. IL4R-targeted Abraxane (IL4RPep-1-Abx) showed more efficient binding and internalization into IL4R-high tumor cells and M2-type macrophages than untargeted Abraxane, which was inhibited in part by an inhibitor of macropinocytotsis and receptor-mediated endocytosis, respectively, while being completely inhibited by an IL4R-blocking antibody. In the same context, IL4RPep-1-Abx induced higher levels of cytotoxicity to IL4R-high tumor cells and reprogramming of M2-type macrophages into M1-like phenotype than untargeted Abraxane. In vivo fluorescence imaging showed that IL4RPep-1-Abx homed to tumor, with little accumulation in the liver and lung, more efficiently than untargeted Abraxane. In addition, IL4RPep-1-Abx inhibited tumor growth and metastasis to the lung in 4T1 or LLC tumor-bearing mice and reduced the number of tumor nodules in the lung of K-ras transgenic mice more efficiently than untargeted Abraxane. Liver function was maintained within the normal ranges after treatment with IL4RPep-1-Abx. In 4T1 and LLC tumor tissues, IL4RPep-1-Abx reduced the population of immune-suppressive cells such as M2-type macrophages and increased that of immune-stimulatory cells such as CD8+ T cells compared with untargeted Abraxane. These results suggest that IL4R-targeted Abraxane can enhance the therapeutic efficacy and anti-tumor immunity of Abraxane and is a promising strategy for targeted cancer therapy. Citation Format: Poongkavithai Vadevoo Sri Murugan, Gunassekaran Gowri Rangaswamy, Byungheon Lee. Interleukin-4 receptor-targeted Abraxane inhibits tumor growth by enhancing drug delivery and reprogramming of M2-type macrophages into M1 phenotype [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 245.

Abstract 4070: Caveolin-1 functions as a potential predictive biomarker for JNTX-101, an albumin encapsulated gemcitabine prodrug

Abstract Purpose: Human serum albumin (HSA) is an attractive candidate as a carrier in developing novel albumin-bound nanoparticle therapeutic drugs. Gemcitabine has been used in the treatment of solid tumors, including non-small cell lung, pancreatic, bladder, and breast cancers. Our previous work in pancreatic and lung cancer models demonstrates that caveolin-1 (Cav-1) enhances uptake of albumin and albumin-conjugated drugs. The aim of this study is to investigate whether the presence of Cav-1 expression alters therapeutic efficacy of JNTX-101, a novel albumin encapsulated gemcitabine prodrug. Experimental design: We first determined the treatment efficacy of JNTX-101 in a panel of 4 pancreatic/lung cancer cell lines (MIAPaCa-2, PANC-1, H23, and HCC15) by alamarBlue cell viability assay. We further established 4 pairs of Cav-1 isogenic cells stably expressing shRNA targeting Cav-1 (shCav-1) or scrambled control shRNA (shCtrl). We investigated whether the absence of Cav-1 expression alters sensitivity of JNTX-101 using alamarBlue cytotoxicity assay and western blotting in both high and low serum conditions. In addition, we tested whether JNTX-101 treatment can alter expression and cellular distribution of Cav-1 as well as other caveolae resident proteins, such as Cav-2 and Cavin-1. Results: Differences in Cav-1 expression resulted in different uptake of albumin prodrug conjugate and Cav-1 depletion attenuated sensitivity of the cells to JNTX-101. Decreased Cav-1 expression markedly reduced JNTX-101-induced apoptosis in a panel of cells in both high and low serum conditions, but particularly in low serum conditions. In addition, our data showed both serum starvation and JNTX-101 independently increased Cav-1 expression in a time-dependent manner (24hrs, 48hrs, 72hrs) similar to gemcitabine, with peak level at 48 hrs post treatment, while other caveolae resident proteins were minimally affected. Conclusions: Our preliminary results suggest that JNTX-101 effectively inhibits cell viability in pancreatic/lung cancer cells and Cav-1 expression dictates sensitivity to JNTX-101, at least partially through reduced apoptotic cell death. These data indicate that Cav-1 may be a potential predictive biomarker of JNTX-101 sensitivity, especially in nutrient deprived conditions. Further study will be performed to explore the impact of Cav-1 expression on JNTX-101 sensitivity in mouse models of pancreatic/lung cancer. Citation Format: Tiantian Cui, Sergio Corrales-Guerrero, Dan Maneval, Curtis Monnig, Patrick Kearney, Sam Ellis, Terence M. Williams. Caveolin-1 functions as a potential predictive biomarker for JNTX-101, an albumin encapsulated gemcitabine prodrug [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 4070.

Paclitaxel Restores Sensitivity to Chemotherapy in Preclinical Models of Multidrug-Resistant Intrahepatic Cholangiocarcinoma.

The treatment of unresectable cholangiocarcinoma (CCA) is limited by the development of resistance to conventional first-line chemotherapy based on gemcitabine (GEM). In addition, a prior treatment with GEM frequently induces cross-resistance to other drugs employed in the second-line. Paclitaxel (PTX) is now emerging as an alternative option for the management of advanced/metastatic CCA. In the present work, we evaluate the antitumor activity of PTX in preclinical models of multidrug-resistant intrahepatic cholangiocarcinoma (iCCA). In vitro, PTX decreases tumor cell viability by affecting the cell cycle and inducing apoptosis and impairs the stem cell compartment. In vivo, a therapeutic regimen containing albumin-bound nanoparticle (Nab)-PTX overcomes drug resistance resulting in delayed tumor growth, impaired organization of the tumor vasculature, and reduced glucose uptake. Together, our results provide a rationale to consider PTX-based regimens in patients with iCCA who became refractory to conventional therapies.

Synergistic effect of microRNA and albumin-bound nanoparticles for inhibition of glioblastoma cancer cell proliferation

The functional significance of upregulation miR-34a in combination with albumin-bound paclitaxel nanoparticles in U251 glioblastoma cell line has been evaluated. The MTT assay determined that miR-34a and albumin-bound paclitaxel nanoparticles can reduce cell viability, but the combination of both factors has a stronger effect on cell viability. The application of qRT-PCR has demonstrated that the transduction of miR-34a could lead to exogenous upregulation of miR-34a level and downregulation of SURVIVIN. Moreover, treatment of U251 cells with miR-34a and nanoparticles together considerably inhibit SURVIVIN expression compared to miR-34a and nanoparticles alone. Flow cytometry showed that upon miR-34a overexpression cell cycle arrested in G1 phase, while treatment with nanoparticles increased the cell population in G2 phase. Upregulation of miR-34a along with treatment with nanoparticles elevated the number of cells arrested in G1/ G2 phases of the cell cycle. Expression of miR-34a with albumin-bound paclitaxel nanoparticles reduced cell viability, downregulated SURVIVIN and enhanced cell cycle arrest in G1/G2 phases. Thus, the upregulation of miR-34a with these nanoparticles are potential candidates therapeutic for glioblastoma cancer.

Abstract 3890: Pharmacodynamic and proteomic analysis of combined gemcitabine/nab-paclitaxel in patient-derived pancreatic cancer xenograft models

Abstract Gemcitabine (GEM) combined with albumin-bound paclitaxel nanoparticles (nab-PTX) is the first-line therapy for patients with metastatic pancreatic adenocarcinoma (PDAC). However, the in vivo mechanisms of drug action and interaction have not been investigated quantitatively for this combination. We evaluated the effects of GEM (100 mg/kg iv weekly) and nab-PTX (equivalent to 30 mg/kg PTX iv weekly), alone or combined, on tumor volume progression in 3 patient-derived xenograft (PDX) PDAC models in SCID mice. The MS1-based quantitative proteomic analysis (IonStar), which offers highly reproducible and accurate quantification with extremely low missing data (<0.5%), was conducted on Days 1, 4, and 8 after dosing to evaluate tumor pharmacodynamic responses in protein expression. Proteins were quantified based on species-specific peptides in order to identify responses of the PDAC cells (human) and tumor-associated stromal cells (murine). A population pharmacokinetic/pharmacodynamic model was developed to quantify tumor growth inhibition by the individual and combined drugs. Tumor growth kinetics were described by a composite function of exponential growth transitioning to linear growth. Treatment effects were represented by a 2nd-order, concentration-dependent parameter k that leads to cell death following delays arising from signal transduction. All 3 PDX models responded to the combination therapy, but with different sensitivities. PDX#14312 showed the least inhibition by the drugs alone (k[GEM]=13.6, k[PTX]=37.0 /day/mM), compared to the other PDXs (#18254: k[GEM]=68.1, k[PTX]=125; 18269: k[GEM]=112, k[PTX]=51.2 /day/mM). Compared to the more potent single-drug treatment for each PDX, the combination resulted in 1.33-fold greater cell death in #14312, 1.39 fold in #18269 and 1.19 fold in #18254. Model simulations showed distinct temporal profiles of cytotoxic signals in the 3 PDXs. Pathway analysis showed that the top changes mediated by the drug combination in PDX#14312 PDAC cells included extracellular matrix organization (FDR-corrected p-value = 7E-5), synthesis of nucleotide di- and triphosphates (p = 0.012), and interferon signaling (p = 0.04), whereas top changes in stroma included increased platelet activation (p = 3.8E-4) and extracellular matrix organization (p = 0.046). These processes represent potential contributors to the resistance of PDX#14312 to the drug combination. Top changes in #18269 and #18254, which were sensitive to the combination, included increased glycolysis (p = 0.038), decreased fatty acid beta-oxidation (p = 3E-5) and DNA replication (p = 0.0058) in PDAC cells, and increased complement activation (p < 1E-5) in stroma. Overall, inter-patient variability in PDAC responsiveness to GEM/nab-PTX therapy may be associated with tumor stress responses partially resembling wound healing processes. Citation Format: Jin Niu, Xue Wang, Shichen Shen, Ju Qu, Donald Mager, Robert M. Straubinger. Pharmacodynamic and proteomic analysis of combined gemcitabine/nab-paclitaxel in patient-derived pancreatic cancer xenograft models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3890.

PATIENTS WITH SEVERE PULMONARY ARTERIAL HYPERTENSION TREATED WITH ABI-009, NAB-SIROLIMUS, AN MTOR INHIBITOR: INTERIM RESULTS FROM A PHASE 1 CLINICAL TRIAL

mTOR activation is implicated in the proliferative aspect of PAH. ABI-009, albumin-bound nanoparticle sirolimus, has anti-proliferative activity and high lung accumulation, and is being explored as a novel treatment approach in patients (pts) with severe PAH. This phase 1 study investigates the

Tumor targeting Salmonella typhimurium A1-R in combination with gemcitabine (GEM) regresses partially GEM-resistant pancreatic cancer patient-derived orthotopic xenograft (PDOX) nude mouse models

ABSTRACTGemcitabine (GEM) is first-line therapy for pancreatic cancer but has limited efficacy in most cases. Nanoparticle-albumin bound (nab)-paclitaxel is becoming first-line therapy for pancreatic cancer, but also has limited efficacy for pancreatic cancer. Our goal was to improve the treatment outcome in patient-like models of pancreatic cancer. We previously established patient-derived orthotopic xenografts (PDOX) pancreatic cancers from two patients. The pancreatic tumor was implanted orthotopically in the pancreatic tail of nude mice to establish the PDOX models. Five weeks after implantation, 50 PDOX mouse models were randomized into five groups of 10 mice for each pancreatic cancer PDOX: untreated control; GEM (100 mg/kg, i.p., once a week for 2 weeks); GEM + nab-PTX (GEM: 100 mg/kg, i.p., once a week for 2 weeks, nab-PTX: 10 mg/kg, i.v., twice a week for 2 weeks); S. typhimurium A1-R (5 × 107 CFU/100 μl, i.v., once a week for 2 weeks); GEM + S. typhimurium A1-R (GEM: 100 mg/kg, i.p., once a week for 2 weeks, S. typhimurium A1-R; 5 × 107 CFU/100 μl, i.v., once a week for 2 weeks). GEM + nab-PTX was significantly more effective than GEM alone in one PDOX model (p = 0.0004), but there was no significant difference in the other PDOX model. The combination of GEM + S. typhimurium A1-R regressed both PDOX models. These results show S. typhimurium A1-R can overcome the ineffectiveness or partial effectiveness of GEM in patient-like models of pancreatic cancer and demonstrate clinical potential for this combination.