Abstract 3069: Involvement of ROS species in amiloride derivative-induced lysosome-dependent cell death in triple-negative breast cancer cells

Cancer Research · 2026-04-03

Abstract Drug resistance leading to cancer recurrence poses a particularly challenging barrier to clinical disease management. Since tumor cells commonly activate anti-apoptotic pathways that cause caspase-dependent pathways to malfunction, cellular resistance to apoptosis is perhaps the most critical factor contributing to the therapeutic failure of conventional and targeted therapeutic agents. Consequently, subpopulations of apoptosis-resistant cells, such as cancer stem cells (CSCs), persist after therapy to seed primary tumor recurrence and metastatic lesions, even after complete remission. The overarching goal of this project is to develop novel drugs that exploit the process of lysosome-dependent cell death, a programmed necrotic cell death mechanism, in suppressing CSC-mediated triple-negative breast cancer. We have previously observed that hexamethylene amiloride (HMA), a derivative of the FDA-approved diuretic amiloride, is cytotoxic in vitro and ex vivo toward cultured cells from a variety of tumor types but not non-transformed cells. HMA also suppresses primary and metastatic tumor outgrowth in vivo. HMA acts on breast tumor cells regardless of subtype, proliferative status, or species of origin. It engages a potent caspase- and autophagy-independent programmed necrotic death mechanism in tumor cells that alters lysosome structure, dysregulates lipid synthesis, leads to lysosomal membrane permeabilization, and acts efficiently toward therapy-resistant CSC-related subpopulations. Although some specifics of the mechanism remain unknown, we examine how the formation of reactive oxygen species is crucial to the induction of necrosis and the potency of HMA and other amiloride derivatives. Citation Format: Noemi Castro, Michelle Hu, Anastasia Berg, Ruiwu Liu, KIT LAM, Kermit Carraway III. Involvement of ROS species in amiloride derivative-induced lysosome-dependent cell death in triple-negative breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 3069.

Abstract 3014: Targeting PLXND1 using RNA bioengineering technologies and customized lipid nanoparticles in advanced prostate cancer

Cancer Research · 2026-04-03

Abstract Background: PLXND1 (Plexin D1) is a transmembrane receptor that plays critical roles in promoting neural lineage plasticity and driving resistance to enzalutamide therapy in prostate cancer. Despite its significance, PLXND1 has been considered "undruggable." siRNA-based therapeutics offer a strategy to silence disease-driving genes like PLXND1 but face limitations, including instability, poor cellular uptake, and off-target effects. Methods: We employed an RNA bioengineering approach using a tRNA/pre-miRNA-mir-34a scaffold to stabilize and express siRNAs targeting PLXND1 (BioRNA-siPLXND1). BioRNA/PLXND1-siRNA expression plasmids were constructed via molecular cloning, and the resulting BioRNA was purified and analyzed for quality, yield, and endotoxin levels. We tested BioRNA-siPLXND1 function in vitro and formulated it into lipid nanoparticles (LNPs) using two lipid components: DOPE and DOTAP. The stability, transfection efficiency, and safety of each formulation were evaluated in vitro and in vivo using prostate cancer cell lines and neuroendocrine prostate cancer (NEPC) patient-derived xenograft (PDX) organoids. Results: BioRNA-siPLXND1 achieved high yield and purity with low endotoxin levels. It efficiently silenced PLXND1 at the mRNA and protein levels, significantly inhibiting cell proliferation, colony formation, and organoid growth in vitro. Among the LNP formulations, LNP-DOTAP demonstrated higher transfection efficiency but greater cytotoxicity in normal cells, whereas LNP-DOPE showed a favorable safety profile and effective delivery. LNP-DOPE-loaded BioRNA-siPLXND1 remained stable for at least 7 days in vitro and suppressed tumor growth in NEPC PDX organoids. In vivo, LNP-DOPE accumulated in tumors within 2 hours, persisted for up to 4 days, and was predominantly retained in tumor tissue by day 7. Conclusions: Our study demonstrates the feasibility and therapeutic potential of a tRNA-based BioRNA platform for delivering PLXND1-targeting siRNAs in prostate cancer. LNP-DOPE serves as a safe and effective delivery system, offering a promising strategy for targeting "undruggable" oncogenes like PLXND1 in therapy-resistant prostate cancer. Financial support: This work was supported in part by grants from NIH/NCI R37CA249108 (Liu), R01CA251253 (Liu), R21CA277171 (Liu), Department of Defense HT9425-23-1-0144 (Liu), HT9425-23-1-0325 (Liu), HT9425-23-1-0324 (Dall’Era), and UC Davis Comprehensive Cancer Center Support Grant (CCSG) awarded by the National Cancer Institute (NCI P30CA093373). Citation Format: Huan Qu, Menghuan Tang, Qiufang Zong, Sohaib Mahri, Pengfei Xu, Joy C. Yang, Fan Wei, Junwei Zhao, Meijuan Tu, Neelu Bartra, Leyi Wang, Allen C. Gao, Kit Lam, Marc A. Dall'Era, Aiming Yu, Yuanpei Li, Chengfei Liu. Targeting PLXND1 using RNA bioengineering technologies and customized lipid nanoparticles in advanced prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 3014.

277P: Preliminary results of LC-SHIELD study: Lung cancer screening in high risk non-smokers with artificial intelligence device

Journal of Thoracic Oncology · 2025-03-01

Planar, Kinked, or Twisted? Molecular Structures of Blue and Red Phase Polydiacetylene Langmuir Films

Langmuir · 2025-06-18 · 2 citations

Polydiacetylenes (PDAs) possess dramatic chromatic transitions, which can be exploited to make stimuli-responsive sensors. Key to developing robust sensors is understanding the changes in molecular structure responsible for these chromatic transitions. We report systematic multiscale studies of different surfactant PDAs using grazing incidence X-ray diffraction (GIXD), X-ray reflectivity (XRR), and atomic force microscopy (AFM) to determine the structure of PDAs in different phases. Monomer films have significant multilayer registry, which is lost after polymerization to the blue phase. Still the monomer and the blue phase are structurally similar: the molecules are uniformly tilted with the diacetylene motif aligned to enable topochemical polymerization. The transition from the monomer to the blue to red phase PDA is not uniform, and at the molecular scale, all three phases may be present within a film. Measurements with Zn2+ in the subphase or boronic acid functionalized PDA precluded the formation of the red phase, enabling blue phase PDA to be characterized unambiguously. In the blue phase, the molecules are uniformly tilted without registry between multilayers. In comparison, red phase PDA adopts a nonplanar conformation with a decrease in molecular tilt. Red phase GIXD patterns can be fit with two potential conformations, a kinked geometry or a twisted geometry. Finally, AFM and XRR measurements reveal that even relatively uniform appearing PDA films are heterogeneous, from no film (bare) regions to monolayer, bilayer, trilayer, and many multilayers at boundaries.

Dynamic Reprogramming of Immune-Related Signaling During Progression to Enzalutamide Resistance in Prostate Cancer

Cancers · 2025-09-30

BACKGROUND: Treatment with androgen receptor (AR) signaling inhibitors, such as enzalutamide, can induce neural lineage plasticity in prostate cancer, potentially progressing to t-NEPC. However, the molecular mechanisms underlying this enzalutamide-driven plasticity, particularly the contribution of immune signaling pathways, remain poorly understood. METHODS: We analyzed transcriptomic profiles of patient samples and prostate cancer cell lines to investigate changes in immune signaling pathways. Interferon gamma (IFNγ), interferon alpha (IFNα), and interleukin 6 (IL6)-Janus kinase (JAK)-signal transducer and activator of transcription 3 (STAT3) signaling were assessed in enzalutamide-sensitive and -resistant prostate cancer cells. Functional assays were conducted to examine cell responsiveness to cytokine stimulation and susceptibility to STAT1 inhibition using fludarabine. RESULTS: Immune-related pathways, including IFNγ, IFNα, IL6-JAK-STAT3, and inflammatory responses, were significantly suppressed in NEPC patient samples compared to those with castration-resistant prostate cancer (CRPC). Enzalutamide-resistant and NEPC cells exhibited markedly impaired IFNγ and IL6 signaling. In contrast, early-stage enzalutamide treatment paradoxically enhanced IFNγ and IL6 responsiveness. Transcriptomic profiling revealed coordinated upregulation of E2F target genes and activation of IFNα/IFNγ and JAK/STAT signaling pathways during early treatment. Importantly, these early-stage cells remained highly sensitive to IFNγ and IL6 stimulation and showed increased susceptibility to STAT1 inhibition by fludarabine, a sensitivity that was lost in resistant cells. CONCLUSIONS: Early enzalutamide treatment enhances immune responsiveness, while the development of resistance is associated with suppressed immune signaling and increased lineage plasticity. These results suggest a therapeutic window where combining enzalutamide with STAT inhibitors may delay or prevent lineage plasticity and resistance.

Designing Programmable Peptide Nucleic Acid‐based Nanovaccines for Anticancer Immune Activation

Small · 2025-11-07 · 1 citations

Abstract Targeted delivery of antigens and adjuvants to the immune cells without eliciting uncontrolled inflammation is a major challenge in cancer vaccine development. Here, a highly versatile and programmable peptide nucleic acid (PNA)‐based vaccine nanoplatform (PVN) is reported to elicit a robust anti‐tumor immune response against B16‐OVA syngeneic melanoma model. The PVN is built on an 11‐mer PNA scaffold, enabling efficient “one‐pot” loading of a PNA‐modified ovalbumin antigenic peptide (SIINFEKL), CpG adjuvant, and a PNA‐derivatized LLP2A ligand (an immune cell and melanoma cell targeting ligand). Super‐resolution fluorescence imaging reveals the spatial arrangement of OVA 8 within LP 10‐12 [ OVA 8 /CpG/LLP2A ], while circular dichroism spectroscopy confirmsparalleled binding of complementary PNA strands in LP 11 [ OVA 8 /CpG/LLP2A ]. LLP2A displayed on PVNs target activated α4β1 integrin expressed by immune and melanoma cells, boosting antigen presentation by dendritic cells and eliciting strong CD8+T cell and natural killer cell responses. This amplified antitumor immune response leads to significant tumor regression and prolonged survival of mice bearing syngeneic B16‐OVA melanoma. The modular nature and versatility of PVN allow convenient one‐pot assembling of peptide antigens, immunomodulators, immune cell and tumor cell targeting ligands, making it practical for the custom design and preparation of personalized cancer vaccines.

My Perspective on OBOC Combinatorial Technology

Methods in molecular biology · 2025-01-01

A phase I first-in-human clinical trial with PLZ4-coated paclitaxel-loaded micelles (PPM) in therapy-resistant non-muscle-invasive bladder cancer (NMIBC).

Journal of Clinical Oncology · 2025-02-10 · 1 citations

806 Background: Approximately 75% of patients with non-muscle invasive bladder cancer (NMIBC) treated with transurethral resection (TUR) followed by intravesical Bacillus Calmette-Guérin (BCG) experience cancer recurrence. When BCG-unresponsive, most patients continue to have recurrences even with newly approved therapies and nearly 30% progress to invasive stages. We developed a first-in-class bladder cancer-specific nanotherapeutic, PPM, which is administered intravesically. Our preclinical data has demonstrated PPM can selectively target bladder cancer cells and deliver paclitaxel payload into these cancer cells following intravesical or intravenous administration. Methods: This is a 3+3 first-in-human dose escalation trial. Eligible patients must have pathologically confirmed NMIBC, be unresponsive to intravesical BCG therapy (with or without cytotoxic chemotherapy), possess adequate vital organ function, and consent to cystoscopy with TUR for response evaluation. PPM is administered via intravesical instillation once weekly for six weeks. The trial features three dose levels, with paclitaxel doses of 25 mg, 50 mg, and 75 mg. The primary endpoints include safety and the recommended Phase II dose; secondary endpoints encompass response rate, duration of response, systemic drug absorption, and molecular correlative studies. Patients will be followed at 3 month intervals for 2 years or until disease progression. Results: To date, three patients with pathologically confirmed NMIBC have completed a total of 18 treatments at the first dose level without any PPM-related adverse events: one patient was unresponsive to BCG and intravesical mitomycin therapy, while the other two had BCG-unresponsive disease. Two out of the three patients achieved ongoing complete remission for over six and nine months, respectively. The third patient demonstrated persistent disease, but no progression was noted. Enrollment for Dose Level 2 is currently open. Conclusions: PPM has demonstrated promising clinical activity without toxicity at the first dose level in patients with BCG-unresponsive NMIBC. Data at other dose levels will be presented at the meeting (ClinicalTrials.gov identifier: NCT05519241). Clinical trial information: NCT05519241 .

Abstract B078: The novel small molecule inhibitor LLS132 reduces pancreatic cancer growth, in part, through modulation of the cell cycle pathway

Cancer Research · 2025-09-28

Abstract Pancreatic ductal adenocarcinoma (PDA) is a highly aggressive cancer with a 5-year survival rate of approximately 13% in the United States, highlighting the urgent need for effective, clinically translatable therapies beyond those currently offering limited benefit. To address this, we developed a novel small-molecule inhibitor, LLS132, and evaluated its safety and efficacy in multiple preclinical models of PDA. We assessed the antiproliferative activity of LLS132 in vitro using human pancreatic cancer cell lines and organoids derived from the genetically engineered LSL-Kras G12D , LSL-Trp53 R172H/+ , Pdx1-Cre (KPC) mouse model. In vivo efficacy and safety were evaluated using subcutaneous and orthotopic pancreatic allograft models, as well as KPC mice. Pharmacokinetics and tumor penetration were analyzed by LC-MS, while RNA sequencing and western blotting were used to identify molecular pathways affected by LLS132. LLS132 inhibited the growth of human pancreatic cancer cell lines and KPC-derived tumor organoids in vitro. In vivo, LLS132 significantly suppressed tumor growth across all tested models. In a subcutaneous allograft model, LLS132 (30 mg/kg, i.p., 5x/week for 1 week) reduced tumor burden by 79% compared to controls, outperforming gemcitabine (100 mg/kg, i.p., 2x/week), which achieved 48% inhibition. In an orthotopic model, LLS132 at 37.5 mg/kg (75% of the maximum tolerated dose, i.p., 5x/week) reduced tumor volume by 43% after 3 weeks and in the clinically relevant KPC model, LLS132 suppressed tumor progression by 65% over 30 days. Importantly, treatment was well tolerated, with no significant weight loss or liver toxicity observed. Pharmacokinetic analysis revealed a maximum plasma concentration of 19063.7 ± 6656.4 ng/mL at tmax = 1.3± 0.5 hours, and a tumor concentration of 111.5 ± 22.5 ng/mg in KPC mice, confirming effective tumor penetration. Transcriptomic analysis of LLS132-treated Panc-1 cells identified cell cycle regulation as a key pathway, with CDK2 emerging as an important target. LLS132 reduced CDK2 expression in both cancer cells and allograft tumor tissue. In conclusion, LLS132 is a promising therapeutic candidate for PDA, exhibiting potent antitumor activity and favorable safety in preclinical models, mediated in part through suppression of CDK2 and modulation of cell cycle pathways. Citation Format: Irena Krga, Laura Musumeci, Hala Addassi, Kit S. Lam, Ruiwu Liu, Gerardo G. Mackenzie. The novel small molecule inhibitor LLS132 reduces pancreatic cancer growth, in part, through modulation of the cell cycle pathway [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research—Emerging Science Driving Transformative Solutions; Boston, MA; 2025 Sep 28-Oct 1; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2025;85(18_Suppl_3):Abstract nr B078.

Versatility and stability of melamine foam-based biosensors (f-ELISA) using antibodies, nanobodies, and peptides as sensing probes

Talanta · 2024-07-29 · 10 citations