Paclitaxel Research Articles

Abstract 2703: Effect of combination of calcipotriol with paclitaxel on pancreatic ductal adenocarcinoma orthotopic mouse model

Abstract Pancreatic ductal adenocarcinoma (PDAC) remains one of the leading causes of cancer-related mortality in the United States, with a dismal 5-year overall survival rate of less than 11%. The progression and treatment resistance of PDAC is heavily influenced by its dense stromal environment, acting as a physical and biochemical barrier, limiting the effective delivery of therapeutics to tumor tissues. This stromal barrier significantly contributes to suboptimal drug efficacy and poor therapeutic outcomes. Calcipotriol (Cal), a known modulator of tumor stroma, may disrupt this barrier and enhance drug delivery to tumors. In this study, we investigated the combination of Cal with paclitaxel (PTX), a commonly used chemotherapeutic agent, to evaluate its ability to improve therapeutic efficacy and drug distribution in a PDAC mouse model. Using an orthotopic Kras* C57bl/6 mouse model of PDAC, we assessed the pharmacokinetics, biodistribution, and antitumor effects of Cal, PTX, and the combination (Cal/PTX). Mice were randomized into four treatment groups: Cal/PTX combination therapy (3 doses of 2 mg/kg /20 mg/kg and 3 doses of 1 mg/kg/10 mg/kg) (N=3), Cal alone (2 mg/kg) (N=3), PTX alone (20 mg/kg) (N=3), and vehicle control (N=4). All treatments were administered intraperitoneally with the solvent Ethanol:Cremophore:Saline (1:1:8) as vehicle and a dosing regimen of 3 days a week (day on day off) for 2 weeks. Tumor intensity was monitored over two weeks using bioluminescence imaging with an IVIS system. Drug concentrations in blood and tumor tissues were quantified using a validated LC-MS/MS method with a lower limit of quantification (LLOQ) of 0.5 ng/ml. In the Cal/PTX group, tumor growth was effectively inhibited, with a 100% response rate observed after 6th dose. Conversely, in the groups treated with Cal or PTX alone, tumor growth continued in 2 out of 3 mice, suggesting limited efficacy of the single agents. Similarly, 3 out of 4 mice showed no signs of tumor regression in the vehicle group. Biodistribution studies further supported these findings, with significantly higher accumulation of both Cal and PTX at the tumor site in the combination group compared to single-agent groups, indicating improved tumor-specific delivery. In the tumor, the mean concentrations (ng/g) (±SD) of Cal and PTX in the combination group were 98.08 ± 55.5 and 147.4 ± 45.07, respectively, compared to 3.71±2.33 and 52.46 ± 21.25 in the alone group. These findings highlight the potential of the Cal/PTX combination therapy to overcome stromal barriers and enhance drug delivery and antitumor efficacy in PDAC. Ongoing work focuses on developing a co-formulated polymeric micelle system (M-Cal/PTX) to be tested on Kras* mouse model to enhance drug delivery further, maximize therapeutic outcomes, and overcome drugs’ associated toxicity. This novel approach could pave the path for more effective treatment strategies for PDAC. Citation Format: Fatima Dagher, Mikayla Skillman, Guodong Zhang, Lu Dai, Amir Mohammad Gholizadeh, Chun Li, Diana S-L Chow. Effect of combination of calcipotriol with paclitaxel on pancreatic ductal adenocarcinoma orthotopic mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2703.

Abstract 6886: Pharmacokinetics of paclitaxel and cyclopamine co-administered via polymeric micelle in HCC mice

Abstract Hepatocellular Carcinoma (HCC) is a highly aggressive form of liver cancer that is typically diagnosed at an advanced stage, leaving limited treatment options. The current non-surgical, first-line treatment, Sorafenib, is non-curative and does not improve patient quality of life. Our study involved pharmacokinetic (PK) analysis of Paclitaxel (PTX) and Cyclopamine (CPA) in an HCC mouse model. PTX is a microtubule-stabilizing drug, while CPA is a Hedgehog signaling pathway inhibitor. Together, the compounds arrest the cell cycle at the M and G phases, preventing tumor cell proliferation. The compounds were co-administered using a polymeric micelle formulation, termed M-CPA/PTX, which contained 2.5 mg each of PTX and CPA, with size of 70.63 ± 3.4 nm, PDI of 0.122 ± 0.038, and encapsulation efficiency of ≥80% for both compounds. The PK was evaluated in HCC transgenic mice expressing the C-MYC oncogene, after IV dosing of M-CPA/PTX at 5 mg/kg/drug every other day for 1, 2, and 3 doses, respectively. The injection volume ranged from 100 - 200 μL based on body weight. The mice were randomized into four groups: vehicle (n = 10), 1 dose (n =8), 2 doses (n=7), and 3 doses (n = 10). After the last dose of each group, PK blood samples were withdrawn at specified time points up to 24 hours when the tumor and organs were harvested. Samples were analyzed using a validated LCMS/MS method with an LLOQ of 0.5 ng/mL, following a liquid-liquid extraction with a volume ratio of 5:1 ACN: H2O (1:1 v/v) to blood sample or tissue homogenates. PK analysis was performed by both 1 and 2-compartment models using Phoenix WinNonlin™ to derive the PK parameters. ANOVA with the Tukey post hoc test was used to compare data across dosing groups with p-value <0.05 for significance. For PTX, the clearance (CL) was 43.17 ± 11.0 L/h/kg, not changing significantly after multiple dosing. The AUC had a notable, but insignificant, increase from 177.1 ± 44.23 h*ng/mL to 193.05 ± 31.76 h*ng/mL. The volume of distribution (Vd) was 91.3 ± 61 L/kg with no appreciable trend across the three groups. For CPA, the CL increased from 23.02 ± 10.34 L/h/kg to 63.48 ± 35.82 L/h/kg and 52.81 ± 31.45 L/h/kg after two and three doses, respectively. The AUC was 253.53 ± 103.2 h*ng/mL after one dose, which decreased to 230.55 ± 99.67 h*ng/mL and 153.96 ± 67.19 h*ng/mL after two and three doses, respectively. The Vd increased from 77.77 ± 12.91 L/kg to 130.57 ± 41.83 L/kg after three doses; however, this increase was not statistically significant. Tumor drug accumulation was also analyzed. In blood, the drug concentrations at 24 hr were below the LLOQ, so the absolute tumor concentration was evaluated. The concentrations were 9.24 ± 5.91 ng/g for PTX and 8.99 ± 4.1 ng/g for CPA. In conclusion, the PK of PTX and CPA in HCC mouse model from single and multiple dosing of M-CPA/PTX were characterized. Multiple dosing yielded no changes in CL and Vd of PTX, but increased CL and decreased AUC in CPA. Citation Format: Emanuel R. Baltrip, Lu Dai, Diana S-L Chow, Chun Li. Pharmacokinetics of paclitaxel and cyclopamine co-administered via polymeric micelle in HCC mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 6886.

Abstract 4234: Synergistic anti-proliferative effects of JIN-001, a novel HSP90 selective inhibitor, in combination with platinum-based drugs in ovarian cancer cell lines

Abstract Introduction: Heat shock proteins (HSPs) have been considered as a promising therapeutic target for ovarian cancer (OC), the most lethal gynecologic malignancy. HSPs facilitate tumor cell adaptation to short-term stress, promoting the development of more malignant phenotypes and the acquisition of resistance to therapeutic treatments over time. To date, Clinical trials of HSP90 inhibitors have shown modest benefits in advanced cancer patients, with no sufficient efficacy as monotherapy. Here, We investigated the anti-proliferative effects of JIN-001, a selective HSP90i, combined with platinum-based drugs in OC cell lines. Material and methods: We examined the co-treatment effects of JIN-001 and paclitaxel (PTX) or cisplatin (Cis, platinum-based) on viability in OC cell lines (OV90, TOV21G, and OVCAR3) and drug-resistance sublines (OV90/PTX200, TOV21G/PTX100, and OVCAR3-CisR). Drug-resistant OC sublines were generated by gradually exposing OC cells to increasing concentrations of PTX or Cis. Each drug was tested either for monotherapy or in 1:1 ratio combination. Also, we assessed the synergistic anti-proliferative effects of JIN-001 (0.1 or 0.05 μM) with Cis on OVCAR3 and OVCAR3-CisR. Results: Co-treatment of JIN-001 with PTX or Cis reduced IC50 in drug-resistant OC sublines compared to PTX or Cis alone. The IC50 of JIN-001 at a fixed dose in combination with Cis were lower in the OVACAR3 and OVCAR-CisR, compared to the single treatment. IC50 (μM) are shown below. Conclusion: The combination of JIN-001 with PTX or Cis enhanced anti-proliferative effects and reduced IC50 in OC cell lines and drug-resistant sublines compared to monotherapy. This suggests JIN-001’s potential as a combination therapy with platinum-based drugs in OC patients. Further studies are needed to examine whether the combination therapy of JIN-001 and the conventional drugs decelerates the tumor’s ability to adapt and develop drug resistance. Citation Format: Jue Young Kim, Ha-Yeon Shin, Anna Jo, Ethan Seah, Choonok Kim, Jae-Hoon Kim. Synergistic anti-proliferative effects of JIN-001, a novel HSP90 selective inhibitor, in combination with platinum-based drugs in ovarian cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4234.

Abstract 5219: Taxanes induce interleukin 6 cytokine in women's cancer and stromal cells in vitro

Abstract Background: Taxane microtubule stabilizers, including paclitaxel (PTX), docetaxel (DTX) and nab-paclitaxel (Nab-PTX), are standard of care in the treatment of women’s cancer alone or in combination with other therapies. The effects of specific taxanes on cancer cells have been well studied such as disruption of cell division and inhibition of cellular trafficking, inducing cancer cell death; however, their effect on the tumor microenvironment is less understood. Cytokines released by cancer cells into the tumor microenvironment such as interleukin 6 (IL-6) can contribute to therapeutic resistance. Specifically, IL-6 binds to the IL-6 receptor (IL-6R) consisting of alpha and beta subunits, and activates the JAK/STAT signaling pathway, promoting chemoresistance. Taxane effects on tumor microenvironment, specifically tumor vasculature, have been less studied. We hypothesized that PTX, DTX, and Nab-PTX, including pericytes, and human dermal lymphatic endothelial cells (HDLECs), result in IL-6 secretion unique to each taxane, promoting chemoresistance. Methods: Primary human pericytes and HDLECs, 5 human women’s cancer cell lines, and 2 human breast epithelial cell lines were grown in vitro. The CCK-8 cell viability/cytotoxicity assay determined IC50 potency for the taxanes in primary human cells and cancer cells. Quantitative-PCR and cytokine arrays were used to evaluate IL-6 transcript levels and protein secretion, and flow cytometry to determine the abundance of IL-6 receptors at the cell surface. Results: DTX had the lowest IC50 values with a range of 0.3 - 2.1 nM, followed by PTX with 1.0 - 4.0 nM, and Nab-PTX with 2.9 - 64.5 nM after 72h treatment across 5 different cancer cell lines. DTX and PTX increased IL-6 transcript levels more than 2-fold following 24h treatment, p<0.05), whereas Nab-PTX showed a slight increase (p > 0.05). MDA-MB-231 cells had the highest basal IL-6 transcript levels compared to cancer and stromal cells. All cells tested expressed both IL-6R subunits at varying levels, suggesting taxane chemoresistance via IL-6R activation is possible in cancer cells and tumor associated cells. Primary human pericytes or HDLECs did not reach 50% survival following 24h treatment of 10 nM taxanes. DTX increased pericyte IL-6 transcript levels by two-fold following 24h treatment, p<0.05. Preliminary cytokine array data revealed IL-6 was increased in 10 nM DTX-treated pericytes following 24h treatment compared to DMSO (2-fold change). Summary: We show that DTX is the most potent taxane following 72h treatment. DTX also induces IL-6 production in both women’s cancer cell lines and stromal cells, potentially contributing to chemoresistance and cancer progression. All cells express varying levels of IL-6R subunits, suggesting that combining DTX treatment with IL-6 inhibitors may prevent DTX resistance in women’s cancer patients. Citation Format: Samantha S. Yee, Jacky Gomez-Villa, Sonia L. Hernandez. Taxanes induce interleukin 6 cytokine in women's cancer and stromal cells in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5219.

Abstract 1788: Exosomal formulation of cannabidiol (CBD) inhibits lung cancer proliferation and enhances uptake and tumor targeting

Abstract Lung cancer remains a leading cause of cancer-related deaths, with treatment specificity posing a major challenge. Thus, we aim to repurpose cannabidiol (CBD) as an antitumor agent, delivered via tumor-targeted exosomes (Exo). We demonstrated that oral CBD administration inhibited orthotopic lung tumor growth by ∼60% (p < 0.01), with enhanced efficacy (∼80%; p < 0.001) achieved using folic acid-functionalized exosomes loaded with CBD. We hypothesized that the enhanced antitumor efficacy is due to 1) increased accumulation at the tumor site due to FA-targeting; 2) improved cellular uptake of CBD via exosomal delivery; and 3) modulation of mechanistic pathways by CBD. To evaluate tumor targeting, FA-Exo labeled with Alexa Fluor-750 (AF750) were administered orally to tumor-bearing mice. Single doses of free AF750, Exo-AF750, and FA-Exo-AF750 were compared (n=3 per group). After 12 hr, mice were euthanized and imaged ex vivo using Odyssey LiCor Imager. For bioavailability studies, female C57BL/6 mice were given a single oral dose of 40 mg/kg CBD or ExoCBD, and tissue CBD levels were quantified 4 hr post-administration. Additionally, ER stress modulation by CBD was assessed in A549 lung cancer cells through analysis of key markers. FA-Exo-AF750 exhibited 3-fold higher signal in tumor tissues compared to non-functionalized exosomes (p<0.01). In bioavailability studies, ExoCBD demonstrated significantly higher CBD levels in the liver (5-fold) and mammary pads (10-fold) compared to free CBD (p<0.001). Notably, free CBD was undetectable in plasma, whereas ExoCBD achieved plasma CBD levels of 500 ng/mL, suggesting enhanced bioavailability and prolonged circulation time. In A549 lung cancer cells, CBD downregulated key ER stress markers, including PERK, IRE1α, BiP, CHOP, Calnexin, and PDI, anti-inflammatory marker NFκB and oncogenic CB2. Furthermore, combination of CBD with paclitaxel (PAC) substantially reduced the IC50 value of PAC against both drug-sensitive (12.5 to 5 nM) and drug-resistant (325 to 80 nM) A549 cells compared to PAC alone. In fact, the activity of PAC and CBD was synergistic against A549 cells, as shown by the combination index (CI = 0.62) calculated using Calcusyn software. Importantly, CBD reversed PAC resistance by downregulating MDR-1 in drug-resistant A549 cells. Overall, tumor-targeted exosomal formulations significantly enhance CBD’s bioavailability, tumor accumulation, and therapeutic efficacy. Combined with its ability to overcome chemotherapy resistance, these findings highlight the promise of CBD-loaded exosomes as a novel therapeutic against lung cancer. Funding: Supported by Agnes Brown Duggan Endowment Funds, the Jewish Heritage Fund for Excellence Research Enhancement Grant and IPIBS Fellowship at the University of Louisville. Citation Format: Disha Nagesh Moholkar, Raghuram Kandimalla, Jeyaprakash Jeyabalan, Ramesh C. Gupta, Farrukh Aqil. Exosomal formulation of cannabidiol (CBD) inhibits lung cancer proliferation and enhances uptake and tumor targeting [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1788.

Abstract 1850: MUC13-targeted PPNPs efficiently inhibited pancreatic tumor growth and influenced tumor immune surveillance

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal types of cancer, characterized by a dismal 5-year overall survival rate, primarily due to lack of early detection and limited effective treatment. Gemcitabine (GEM) is most effective therapy for pancreatic cancer (PanCa), but it only offers a marginal survival benefit of 6 months. A combination of Paclitaxel (PTX) albumin nano-formulation (Abraxane) and GEM has shown marginal improvement in PanCa treatment. This poor treatment response has been associated with desmoplastic stroma, microbiome effects, altered tumor microenvironment (TME), suppressive immune cells and PDAC-specific signaling pathways. Our research has demonstrated that MUC13 is highly overexpressed in PanCa and is associated with cancer progression and metastases. Considering these facts, we have generated an MUC13 antibody targeted nanoparticle formulation for tumor specific targeted delivery of paclitaxel using a multi-layered Pluronic F127 and polyvinyl alcohol stabilized and poly-L-lysine coated poly(lactic-co-glycolic acid) nanoparticles (PPNPs) to improve therapeutic outcome of PanCa therapy. Our MUC13-targeted PPNPs (MUC13-PPNPs) showed enhanced cellular uptake of MUC13-PPNPs formulation in HPAF-II (MUC13+) compared with Panc-1 (MUC13) PanCa cells as determined by immunofluorescence. Further, our novel formulation effectively inhibits growth and metastatic phenotypes in MUC13+ cells as compared with MUC13- cells of PanCa in vitro. In our PanCa xenograft mouse model (HPAF-II + stromal cells), we found that PPNPs alone significantly inhibited growth of tumor (P < 0.05 when compared with control (PLGA) and treatment group PTX. Furthermore, the tumor volume of MUC13-PPNPs group was not only highly significantly lower than control PLGA and PTX (P < 0.05), but also lower than PPNPs alone group (P < 0.05) or control (P < 0.05). Our findings also demonstrated that PPNPs/MUC13-PPNPs synergize GEM therapy response in vitro and in vivo mouse models. Further, tumor tissue treated with PPNPs/MUC13-PPNPs demonstrate the downregulated expression of sonic hedgehog and other oncogenic signaling axis determined by qPCR, Western blots, and immunofluorescence analyses. Additionally, our nano formulation effectively reduced tumor volume in syngeneic orthotopic xenograft mouse model involving injection of KPC-Luc in C57Black/6 mice and target tumor-associated macrophages (TAM) by repolarizing M2 into M1 phenotype via inhibiting expression of M2 markers and an increase in M1 markers. In conclusion, we observed that our novel formulation has high therapeutic ability for achieving pancreatic tumor specific delivery PTX, synergize GEM therapy response and altered the tumor immune surveillance mechanisms. Thus, this unique approach can effectively enhance therapeutic efficacy main line chemotherapies and immune checkpoint immunotherapies. Citation Format: Vivek Kumar Kashyap, Neeraj Chauhan, Mohammed Sikander, Eswara N. Ghali, Fnu Shabnam, Rahul Tiwari, Sheema Khan, Bilal B. Hafeez, Murali M. Yallapu, Meena Jaggi, Subhash C. Chauhan. MUC13-targeted PPNPs efficiently inhibited pancreatic tumor growth and influenced tumor immune surveillance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1850.

Abstract 3141: Development and comprehensive preclinical evaluation of dual-drug polymeric micelles ONP-001 for PDAC and HCC

Introduction: Pancreatic ductal adenocarcinoma (PDAC) and hepatocellular carcinoma (HCC) remain the leading causes of cancer-related mortality, with poor outcomes. This study comprehensively evaluated the mechanisms of polymeric micelles co-encapsulating cyclopamine (CPA) and paclitaxel (PTX) (M-CPA/PTX, ONP-001) and the effectiveness against HCC and PDAC. The dual-drug delivery system targets embryonic signaling pathways, such as Hedgehog (Hh), which drives tumor progression and resistance. Methods: CPA and PTX were encapsulated in micelles (∼55 nm in size) to improve bioavailability and tumor concentrations. Preclinical experiments included in vitro assays for cytotoxicity, tumorsphere, and colony formation in both cancer cell lines. In vivo models included orthotopic Kras* cell implanted PDAC and spontaneous HCC in transgenic LAP-tTA/TRE-MYC mice. The antitumor efficacy was examined by intravenously injection of ONP-001 at 2.5, 5.0, and 7.5 mg/drug equivalent/kg thrice weekly for 4 weeks, as well as combination regimens with irreversible electroporation (IRE) and an immune checkpoint inhibitor. Survival, tumor burden, immune modulation, and cytokine profiles were analyzed using Kaplan-Meier survival curves, bioluminescence imaging, and multiplex cytokine assays. Results: In the PDAC model, ONP-001 significantly extended median survival at 2.5 mg equivalent drug/kg (p<0.01), 5.0 mg/kg (p<0.0001), and 7.5 mg/kg (p<0.05) compared untreated control. ONP-001 administered at 7.5 mg/kg displayed shorter median survival than 5.0 mg/kg suggesting that the optimal regimen tested was 5 mg/kg. ONP-001 reprogrammed tumor stroma, and reduced cancer stem cell (CSC)-associated tumorsphere formation. Combination of ONP-001 with IRE and anti-PD-1 further enhanced survival and immune infiltration, overcoming PDAC’s immunosuppressive microenvironment. In HCC, ONP-001 significantly inhibited tumor growth and colony formation. Tumor cytokine profiling revealed significant reductions in markers associated with CSC maintenance (e.g., IL-15, IL-33) and tumor progression, highlighting an anti-inflammatory effect on the tumor microenvironment. Studies in the transgenic HCC model also confirmed significantly greater antitumor efficacy for ONP-001, with no observed hepatotoxicity, compared to sorafenib treatment. Conclusion: ONP-001 was an effective therapeutic strategy for PDAC and HCC, targeting CSCs, modulating the stroma, and enhancing immunotherapy, at 5.0 mg/kg, TIW, with enhanced benefits when in combination regimens. Ongoing studies will further characterize the pharmacokinetics, tumor uptake and biodistribution of both drugs. The data supports further development of ONP-001 for potential future clinical development. Citation Format: Qiu-Xu Teng, Guodong Zhang, Lu Dai, Defeng Deng, Ping Pan, Diana S-L Chow, Guorong Ma, Peiying Yang, Chun Li. Development and comprehensive preclinical evaluation of dual-drug polymeric micelles ONP-001 for PDAC and HCC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 3141.

Abstract 1213: Immune aging impedes intratumoral T-cell activity to reduce response to therapy in triple negative breast cancer

Abstract Age is the biggest risk factor for developing most cancers, including breast cancer. While over 50% of cancer cases occur in patients over 65, fewer than 25% of patients enrolled in clinical trials are in this age range. Furthermore, most preclinical trials are performed in young mice, meaning that from the preclinical through clinical stages trials do appropriately reflect the patients most affected by cancer. Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer which lacks targeted therapies, and as such is typically treated with a combination of chemotherapy, such as paclitaxel (PTX), and immunotherapy, such as anti-PDL1. With age, there is also a characteristic change in immune fitness - expansion of myeloid cells, increase in inflammatory cytokines, decrease in naïve T cell pools - suggesting that patients of different ages will respond differently to immunotherapies which rely on immune fitness. It is not completely known how age impacts TNBC therapeutic responses, as most studies have been underpowered to properly study the impact of age. We utilized a preclinical model where young (8-10 week old) and aged (12-16 month old) FVB mice display hallmarks of immune aging in their peripheral blood. Orthotopic injection of syngeneic TNBC tumor cells, Met1, results in tumors that are more aggressive in young mice, but also more responsive to anti-PDL1, PTX, and particularly to a combination of both. This is accompanied by an increase in CD8+ cytotoxic T-cell infiltration in aged control mouse tumors, but no further increase in infiltration with treatment. This is opposite in young mice which see a robust increase in T-cell infiltration with treatment, highlighting their improved response to therapy. Depletion of cytotoxic CD8+ T-cells leads to faster tumor growth in both young and aged mice, but completely abrogates any age-associated difference in tumor growth, demonstrating the critical role of immune aging in this age-associated phenotype. Bulk RNAseq suggests that tumors in aged mice are enriched for IFNg-response programs. Treatment with anti-IFNg antibodies alone has no impact on tumor growth, but completely blocks any response to anti-PDL1 in young mice, with no impact on the aged mouse anti-PDL1 response. Flow cytometry reveals that the tumor-infiltrating CD8s in aged mice have decreased CD107a and IFNg expression, markers of CD8+ T-cell activity and activation. Further, IFNg+ CD8s in aged mice show signs of increased T-cell exhaustion by PD1, TIM3, and LAG3 expression. These data demonstrate that immune aging significantly impacts T-cell function leading to age-associated differences in disease progression and therapeutic response. Our continued work to target T-cell activity and infiltration via IFNg-response programs in the tumor microenvironment will lead to age-stratified treatment options and improved therapeutic outcomes for patients of all ages. Citation Format: Milos Spasic, Melissa Dolan, Adrienne Parsons, Dimitry Lineker, Elizabeth Mittendorf, Peter van Galen, Sandra McAllister. Immune aging impedes intratumoral T-cell activity to reduce response to therapy in triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1213.

Abstract 2692: 3D in vitro models for identifying primary vs. metastatic tumors in targeted breast cancer treatment

Abstract Metastatic disease is responsible for over 90% of cancer-related deaths, with breast cancer patients exhibiting a survival rate of only 5% once bone metastases develop. Traditional 2D in vitro models often fail to accurately replicate the tumor microenvironment (TME) and drug responses observed in vivo. To address these limitations, we utilized advanced 3D in vitro models to better simulate primary and metastatic tumors, enabling the study of cancer-stromal interactions and drug efficacy. Patient-derived cancer cells (PDCs) from three molecular subtypes of breast cancer were used to model both primary tumors (using a hanging drop system) and bone metastases (using a bioengineered bone-mimetic scaffold). Stromal components, including endothelial cells (ECs), macrophages, and cancer-associated fibroblasts (CAFs), were co-cultured with PDCs to mimic TME more closely. As expected, drug sensitivity profiles generated within 48 hours revealed significant differences between 2D and 3D models when treated with paclitaxel (PTX), doxorubicin (DOX), lapatinib (LAPA), and 4-hydroxy tamoxifen (4-OH TAM). PDCs at bone metastatic sites exhibited higher survival rates post-treatment, as indicated by elevated BCL2 and Ki67 expression and lower CAS9 expression compared to primary tumor sites. This suggests site-specific resistance mechanisms, emphasizing that bone metastases may require higher drug doses to achieve comparable efficacy. Stromal interactions significantly influenced angiogenic capacity. While drug treatments substantially altered network formation when ECs and PDCs were cultured together, the presence of CAFs produced opposing effects. These findings underscore the complexity of bone TME and suggest that higher drug doses or combination therapies may be necessary to effectively target metastatic tumors. Additionally, we are incorporating macrophages into the TME in ongoing experiments to further elucidate their contributions to angiogenesis and therapeutic resistance. Moving forward, we will employ single-cell sequencing of 3D models to investigate tumor heterogeneity and refine dose-specific treatments, advancing precision medicine strategies to combat metastasis and improve patient outcomes. This work is currently in progress. Our single-cell sequencing data aims to reveal distinct gene expression differences between primary tumor sites and metastatic sites within the tumor microenvironment. By identifying unique gene expression profiles in cancer cells, stromal cells, and immune cells at each site, we aim to uncover critical pathways driving metastasis. These findings will guide the development of targeted therapies that specifically address metastatic tumors, thereby preventing metastasis and minimizing off-target effects. Citation Format: Shrinwanti Ghosh, Sangdeuk Ha, Anu Gaba, Kalpana Katti, Jiha Kim. 3D in vitro models for identifying primary vs. metastatic tumors in targeted breast cancer treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2692.

Thrombospondin-1 induces immunogenic cell death in human mucoepidermoid carcinoma MC-3 cells via the PERK/eIF2α signaling pathway: potential implications for tumor immunotherapy

ObjectiveTo investigate whether Thrombospondin-1 (TSP-1) induces immunogenic cell death (ICD) in human mucoepidermoid carcinoma (MC-3) cells and explore its potential to induce calreticulin (CRT) exposure via the PERK/eIF2α signaling pathway.MethodsThe MC-3 cell line was used as the research model. The CCK-8 assay was performed to determine the optimal seeding density, TSP-1 concentration, and treatment time. Annexin V/PI double staining combined with flow cytometry was used to assess apoptosis across different experimental groups (blank control, TSP-1, paclitaxel (PTX), TSP-1 + PTX). Cells were divided into groups: blank control, PTX, TSP-1, TSP-1 + ISRIB (ISRIB: Integrated Stress Response Inhibitor), and TSP-1 + PTX, and CRT expression was detected by flow cytometry. Immunofluorescence, Western blot, and qPCR were used to detect the expression of PERK (Protein Kinase R-like Endoplasmic Reticulum Kinase), eIF2α (eukaryotic Initiation Factor 2α), and CRT. All experiments were performed in triplicate, and data were analyzed using GraphPad Prism 8.0 software. Statistical significance was set at P < 0.05.ResultsAt a seeding density of 2 × 104/mL, MC-3 cells reached the growth plateau by day six. The optimal concentration and duration of TSP-1 treatment were 0.1 μmol/L and 72 h, respectively. Flow cytometry, immunofluorescence, Western blot, and qPCR results revealed that TSP-1 significantly induced CRT exposure in MC-3 cells (P < 0.05), accompanied by the upregulation of PERK and eIF2α expression (P < 0.05). Co-treatment with PTX further enhanced these effects, while the addition of ISRIB reduced the expression of PERK, eIF2α, and CRT (P < 0.05).ConclusionTSP-1 induces ICD in MC-3 cells, accompanied by CRT exposure, potentially mediated through the activation of the PERK/eIF2α signaling pathway. These findings suggest that TSP-1 may have potential as an adjunct to chemotherapy for enhancing tumor immunotherapy.

Unravelling Paclitaxel Resistance in Gastric Cancer: The Role of Small Extracellular Vesicles in Epithelial Mesenchymal Transition and Extracellular Matrix Remodelling

Background: Gastric cancer (GC) is a highly aggressive disease often complicated by resistance to chemotherapy agents like paclitaxel (PTX), which targets microtubules to induce apoptosis. Resistance arises through complex molecular mechanisms, including the overexpression of pro-angiogenic factors (VEGFA, ANG-2), activation of survival pathways (PDGFRβ, PPARγ), and epithelial-mesenchymal transition (EMT) driven by proteins such as VIM, E-CAD, N-CAD, and FLOT-1. The extracellular matrix (ECM), regulated by COL1A1 and influenced by PPARγ, acts as a physical barrier to drug penetration. Small extracellular vesicles (sEVs) have emerged as critical mediators of intercellular communication and may influence these resistance pathways. Methods: This study investigated the role of sEVs isolated from metastatic GC patients treated with Ramucirumab and PTX. Patients were stratified by progression-free survival (PFS) into rapidly progressing (RP) and controlled disease (CD) groups. sEVs from these patients were applied to HCEC-1CT and HEPA-RG cell lines. Cell viability assays, gene and protein expression analyses, and bioinformatic studies were conducted to assess the impact of sEVs on resistance-related markers. Results: Results showed that sEVs from CD patients reduced the expression of markers associated with drug resistance, while sEVs from RP patients increased these markers, promoting angiogenesis, EMT, and ECM remodeling. These changes correlated with enhanced cell survival and resistance phenotypes. Bioinformatic analyses confirmed that sEVs modulate inflammation, ECM dynamics, and EMT pathways. Conclusions: In conclusion, sEVs from metastatic GC patients significantly influence chemoresistance and tumor progression. Targeting sEV-mediated signaling may offer novel therapeutic strategies to overcome resistance and improve treatment outcomes in gastric cancer.

Size-Tunable Micro-Nano Liposomes: Enhanced Lung Targeting and Tumor Penetration for Combination Treatment of Lung Cancer.

The inefficient delivery of nanocarriers and drug resistance seriously limit therapeutic effects of lung cancer. Here, a size-tunable micro-nano liposome system, PCAL@TM, is designed for targeted delivery of paclitaxel (PTX) and oxygen to lung tumors. PTX-loaded corosolic acid (CA) nano-liposomes (PCAL, 100nm) are anchored to the surface of oxygenated perfluorotributylamine (TBA)-loaded multivesicular liposomes (TM, 10µm) via the biotin-avidin interactions with matrix metalloproteinase-9 (MMP-9) cleavable linker. After intravenous administration to lung tumor-bearing mice, the distribution amount of PCAL@TM in the lungs is extremely higher than that in the liver and spleen. The MMP-9-sensitive PCAL@TM can decouple into nano-PCAL and micro-TM in tumors; while, TMs enable breaking into smaller vesicles under vascular pressure, and release oxygen leading to the downregulation of HIF-1α and platelet-activated TGF-β. Meanwhile, PCAL can penetrate deeply into tumor by the tumor-targeted-penetrable CA liposomes, to promote the reduction of inflammation levels and enhance PTX-induced immunogenic cell death (ICD). Together, these results lead to the reversals of chemoresistance and tumor immunosuppressive, achieving significant improvement in PTX chemotherapy and α-PD-1 immunotherapy. The PCAL@TM system presents a novel strategy to enhance the efficiency of nano-drug delivery and the outcome of combined therapy for lung tumor.

Biotemplated Diatom Microrobots for Dual-Drug Delivery in Targeted Neuroblastoma Therapy.

Neuroblastoma, a highly malignant pediatric tumor, demands innovative targeted drug delivery strategies to overcome the limitations of conventional therapies. In this study, we developed magnetic diatom microrobots (DMs) using diatom frustules as biotemplates, leveraging their natural hierarchical porosity and biocompatibility. Functionalized with amino groups and folic acid, these microrobots demonstrated enhanced drug conjugation and tumor-targeting capabilities. Designed to carry either cisplatin (CDDP) or paclitaxel (PTX), the DMs facilitated complementary therapeutic effects through pH-responsive release, enabling synergistic neuroblastoma therapy. Magnetic actuation tests confirmed multimodal propulsion and precise motion control. In vitro experiments demonstrated enhanced therapeutic efficacy and reduced off-target effects compared to those of conventional approaches. These diatom-templated magnetic microrobots, with their facile fabrication and superior performance, represent a promising platform for targeted drug delivery and advanced cancer therapy.

GSH-Responsive Heterodimeric Dual-Targeted Nanomedicine Modulates EMT to Conquer Paclitaxel-Induced Invasive Breast Cancer Metastasis.

Paclitaxel (PTX), although effective against primary breast cancer, presents formidable clinical challenges due to severe toxicity and pro-metastatic potential, a critical concern as distant metastasis causes 90% of breast cancer-related deaths. To address these limitations, we designed and prepared a tumor microenvironment-responsive nanoprodrug, PTX-SS-3'HPT@RGD-HA NPs, that engineered RGD peptide-modified hyaluronic acid (HA) nanocarriers encapsulating the antimetastatic 3'-hydroxy pterostilbene (3'HPT) and PTX heterodimer linked by a glutathione (GSH)-cleavable disulfide bond. These nanoparticles targeting CD44 and αvβ receptors overexpressed in aggressive breast cancer cells and synergized enhanced permeability and retention effects with receptor-mediated endocytosis, facilitating superior tumor-specific drug deposition and GSH-activated payload release in vitro and in vivo. Moreover, PTX-SS-3'HPT@RGD-HA NPs achieved excellent tumor growth inhibition while mitigating systemic toxicity and metastatic risks in 4T1 tumor-bearing mice. Mechanistically, 3'HPT counteracted PTX-induced epithelial-mesenchymal transition by downregulating MMP-9/N-cadherin and restoring E-cadherin expression, thereby neutralizing PTX-triggered pro-metastatic effects. This study pioneers a dual-targeted, toxicity-shielding nanoplatform that simultaneously improves therapeutic efficacy and addresses chemotherapy-driven metastasis, offering a revolutionary strategy for managing highly invasive breast cancer.

Differences in chemotherapeutic drug sensitivity before and after patient-derived tumor organoid construction.

Differences in chemotherapeutic drug sensitivity before and after patient-derived tumor organoid construction.

Targeting PFKFB4 Biomimetic Codelivery System Synergistically Enhances Ferroptosis to Suppress Small Cell Lung Cancer and Augments the Efficacy of Anti-PD-L1 Immunotherapy.

Small cell lung cancer (SCLC) is an extremely aggressive and highly malignant type of lung cancer that frequently develops resistance and recurrence following initial treatment. Paclitaxel (PTX) is a second-line therapeutic option for SCLC patients with resistance to first-line treatment. However, its clinical application is limited due to suboptimal efficacy and the risk of hypersensitivity reactions. To address these challenges, a novel therapeutic strategy employing a cationic liposome-based biomimetic drug co-delivery system, siPFKFB4/PRLPTX@RBCM-cRGD, which simultaneously delivers paclitaxel and PFKFB4-targeting small interfering RNA (siRNA) to SCLC cells and tissues is proposed. These findings demonstrate that this co-delivery system can induce ferroptosis in SCLC cells, thereby enhancing their sensitivity to paclitaxel. Moreover, It promotes the infiltration of immune cells and the secretion of cytokines within the SCLC immune microenvironment, effectively activating anti-tumor immunity. When combined with anti-PD-L1 antibodies, it further potentiates anti-tumor immune responses. These results suggest that the biomimetic codelivery system not only induces ferroptosis to enhance paclitaxel efficacy but also reprograms the SCLC immune microenvironment, thereby potentiating the effects of anti-PD-L1 immunotherapy and providing a promising new therapeutic strategy for SCLC.

Injectable anticancer biodegradable hydrogel-based nanocomposites: Synergistic pH-responsive paclitaxel/β-cyclodextrin nanocomplex delivery in polyvinyl alcohol hydrogel for targeted pancreatic ductal adenocarcinoma treatment.

Injectable anticancer biodegradable hydrogel-based nanocomposites: Synergistic pH-responsive paclitaxel/β-cyclodextrin nanocomplex delivery in polyvinyl alcohol hydrogel for targeted pancreatic ductal adenocarcinoma treatment.

Protein-based nanocarriers for paclitaxel (PTX) delivery in cancer treatment: A review.

Protein-based nanocarriers for paclitaxel (PTX) delivery in cancer treatment: A review.

Tenacissoside G reverses paclitaxel resistance by inhibiting Src/PTN/P-gp signaling axis activation in ovarian cancer cells.

Ovarian cancer (OC) is the most common malignant gynecologic tumor, with the highest mortality rate among female reproductive system cancers. Resistance to chemotherapy drugs, which often develops after long-term use, is a major cause of treatment failure. In recent years, traditional Chinese medicine has been widely used in the treatment of tumor for their advantages in improving the efficacy of chemotherapy and alleviating the toxic side effects. Tenacissoside G (Tsd-G), as one of the main active ingredients of Marsdenia tenacissima, exhibits anti-tumor effects. However, its impact on ovarian cancer is not well understood. To assess the role and mechanism of Tsd-G in reversing paclitaxel (PTX) resistance, the reversal fold of Tsd-G in combination with PTX on OC PTX-resistant (A2780/T) cells was determined using CCK-8 assay. The apoptosis level and migration ability of A2780/T cells after 24h treatment with Tsd-G and PTX were assessed by Hoechst 33,342, flow cytometry, and wound healing assay. Western Blot and Src overexpression plasmid were used to explore the relationship between Src and PTX resistance. The relationship between Src expression and human OC was analyzed by gene expression database. The effect of Tsd-G on P-gp activity was detected by flow cytometry. Western blot and RT-PCR experiments were performed to detect the differences in mRNA and protein expression of Src/PTN/P-gp signaling axis to validate the mechanism of Tsd-G in reversing the resistance to PTX in ovarian cancer. The results showed that Tsd-G reverses PTX resistance in ovarian cancer cells by regulating cell proliferation, cell cycle, inducing apoptosis, and inhibiting migration. The mechanism might associate with the inhibition of Src expression and phosphorylation activation, which in turn inhibits the expression and activity of downstream PTN and P-gp. This study provides a new idea for the treatment of PTX-resistant OC patients and provides theoretical support for revealing the anti-ovarian cancer active ingredients in Marsdenia tenacissima.

Inhibiting Chemotherapy Immune Tolerance and Reversing Tumor Microenvironment by Macrophage‐Targeted Nanohybrid Systems for Enhancing Tumor Chemo‐Immunotherapy

AbstractChemotherapy combined with immunotherapy (chemo‐immunotherapy) has emerged as a critical strategy in tumor treatment. However, chemotherapy induced immune tolerance and the immunosuppressive tumor microenvironment limit its effectiveness. Secondary necrosis can generate additional immunogenic substances, enhancing the immunogenicity of tumor cells, but macrophage‐mediated clearance of apoptotic cells inhibits the occurrence of secondary necrosis. In this study, a tumor‐associated macrophage (TAM)‐targeting nanohybrid system, SC@P@U, is designed by combining poly (lactic‐co‐glycolic acid) (PLGA)‐loaded MerTK inhibitor UNC2025 (P@U) with saccharomyces cerevisiae‐derived β‐glucan (SC shell). This nanohybrid system specifically targets TAMs, preventing them from clearing apoptotic tumor cells induced by chemotherapy and inhibiting their polarization into immune‐suppressive M2 macrophages. More importantly, it activates the macrophage STING pathway, further stimulating dendritic cells and initiating T cell‐mediated immune responses. In vivo experiments demonstrated that SC@P@U, when combined with paclitaxel (PTX), significantly suppressed tumor growth, activated anti‐tumor immunity, and, when used in conjunction with the immune checkpoint inhibitor αPD‐1, markedly enhanced the anti‐tumor effect. This strategy overcomes chemotherapy immune tolerance in traditional chemo‐immunotherapy, reverses the immunosuppressive tumor microenvironment, and offers a promising approach to tumor treatment.