Cancer Cell Death Research Articles

Binary nanoconjugation of zein–methylcellulose for improving curcumin properties: solubility, controlled release and anticancer activity

AbstractFor cancer treatment, a novel nanocarrier has been developed, utilizing natural compounds. Zein protein (Z) and methylcellulose (MC) polysaccharide were formulated as a nanocarrier for nutraceutical curcumin (Cur). The zein–methylcellulose nanoconjugate (ZMC) appeared spherical/monodispersed in transmission electron microscopy images. Hydrodynamic sizes were 164 ± 20.2 and 190 ± 28.2 nm for ZMC and ZMC@Cur, respectively. For both formulations, zeta potential, differential scanning calorimetry, Fourier transform infrared spectroscopy and X‐ray diffraction analyses were conducted. Curcumin encapsulation efficiency was 92%, and its release profile was pH responsive. Using MTT assay, ZMC@Cur demonstrated a significant cytotoxic effect against MCF‐7 and HepG2, surpassing the impact of curcumin. This underscores the pivotal role of ZMC@Cur in enhancing curcumin properties, thereby potentiating cancer cell death. Compared with free curcumin, ZMC@Cur markedly promoted DNA damage in cancer cells, owing to precise curcumin targeting into the nucleus. Accordingly, the proposed bionanocomposite stands as an efficient vehicle for curcumin, showcasing its crucial role in combating cancer via improving the pharmaceutical properties of curcumin. © 2024 Society of Chemical Industry.

Dual roles of inflammatory programmed cell death in cancer: insights into pyroptosis and necroptosis.

Programmed cell death (PCD) is essential for cellular homeostasis and defense against infections, with inflammatory forms like pyroptosis and necroptosis playing significant roles in cancer. Pyroptosis, mediated by caspases and gasdermin proteins, leads to cell lysis and inflammatory cytokine release. It has been implicated in various diseases, including cancer, where it can either suppress tumor growth or promote tumor progression through chronic inflammation. Necroptosis, involving RIPK1, RIPK3, and MLKL, serves as a backup mechanism when apoptosis is inhibited. In cancer, necroptosis can enhance immune responses or contribute to tumor progression. Both pathways have dual roles in cancer, acting as tumor suppressors or promoting a pro-tumorigenic environment depending on the context. This review explores the molecular mechanisms of pyroptosis and necroptosis, their roles in different cancers, and their potential as therapeutic targets. Understanding the context-dependent effects of these pathways is crucial for developing effective cancer therapies.

Royal Jelly–Mediated Silver Nanoparticles Show Promising Anticancer Effect on HeLa and A549 Cells Through Modulation of the VEGFa/PI3K/Akt/MMP‐2 Pathway

ABSTRACTIn recent years, nanotechnology has revolutionized various sectors, particularly in nanomedicine, where nanomaterials are used for diagnosis, monitoring, control, prevention, and treatment. Among these, silver nanoparticles (AgNPs) stand out due to their remarkable antimicrobial and cytotoxic properties. Traditional chemical synthesis of AgNPs poses significant environmental and health risks. This study introduces a novel, eco‐friendly synthesis method using royal jelly (RJ), a nutrient‐rich secretion from honeybees, to produce AgNPs with potent anticancer effects. Our research provides a detailed investigation into RJ‐mediated AgNPs’ modulation of the VEGFa/PI3K/Akt/MMP‐2 pathway in HeLa and A549 cancer cell lines. AgNP characterization was performed by applying UV–Vis spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM) in combination with selected area electron diffraction (SAED). Cell signaling system components were determined by ELISA analysis. The cells were subjected to staining with hematoxylin and eosin to visualize the treatment’s effects. This study focuses on the green synthesis of AgNPs using RJ and its bioactivity against cancer cells. It provides a detailed characterization of the nanoparticles and examines their effects on cancer cells, specifically HeLa cervical cancer and A549 lung cancer cell lines. Green synthesized AgNPs demonstrate significant cytotoxic effects against HeLa and A549 cancer cell lines. The underlying molecular mechanisms contributing to their anticancer activity were elucidated. Our findings revealed a significant decrease in arginase activity upon exposure to AgNPs, accompanied by reductions in PI3K and phosphorylated and total Akt levels, indicative of pathway inhibition. Additionally, RJAgNP demonstrated a capacity to reduce nitric oxide levels and suppress angiogenesis‐related factors like VEGF and MMP‐2 and inflammation‐related factors like TNF‐α and COX‐2, thus impeding angiogenesis and metastasis. Moreover, our results shed light on the involvement of reactive oxygen intermediates (ROIs) in mediating apoptotic pathways, as evidenced by the increase in malondialdehyde (MDA) concentration and the corresponding decrease in Akt levels, ultimately promoting death in cancer cells. Our study contributes significantly to the field of nanomedicine and cancer therapy by introducing the use of green synthesis AgNPs using RJ and providing in‐depth insights into their molecular mechanisms of anticancer action. Our research findings demonstrate the anticancer potential of RJ‐AgNPs by targeting the VEGFa/PI3K/Akt/MMP‐2 pathway and modulation of ROS/RNS in cancer cells.

Construction of drug-free sodium bicarbonate nanoparticles with high water-tolerance for gas therapy to selectively induce non-apoptotic death of cancer cells

Developing drug-free nanotherapeutics is extremely appealing provided they could achieve effective therapeutic performances. This study proposes a sodium bicarbonate-dependent gas therapy modality targeting fragile lysosomes of cancer cells through carbon dioxide-induced lysosomal rupture. Interestingly, we reveal that this gas therapy induces cell death through the combination of necrosis, pyroptosis and ferroptosis, rather than the conventional apoptosis pathway. Notably, the high water-solubility of sodium bicarbonate presents a significant challenge in engineering its nanotherapeutics that require long-term water-tolerance for its intravenous delivery. To address this issue, an EPDPPP approach is here developed under aqueous conditions. Without any anticancer drugs, the sodium bicarbonate nanoparticles alone can selectively kill cancer cells with high specificity. Thanks to the high water tolerance, the sodium bicarbonate nanoparticles coated with cancer cell membranes have shown favorable performance in targeting and inhibiting tumors after intravenous administration. This water-tolerant sodium bicarbonate nanoplatform is expected to have potential applications in various medical fields, including the targeted gas therapy. Additionally, this study may suggest a viable direction for developing water-tolerant nanoparticles derived from water-soluble inorganic salts.

GPX4 Inhibition Enhances the Antitumor Effect of PARP Inhibitor on Homologous Recombination Proficient Ovarian Cancer Cells.

Poly (ADP-ribose) polymerase inhibitors (PARPi) are now widely used in BRCA1/2 mutation or homologous recombination (HR) deficiency ovarian cancer but have limited efficacy in HR-proficient patients. GPX4 is a key regulator of ferroptosis and has been proven to be associated with multiple drug sensitivities. As a molecule that regulates the sensitivity of multiple drugs, the relationship between GPX4 and the efficacy of PARPi in HR-proficient ovarian cancer has not been elucidated. In this study, siRNA transfection was used to regulate the expression of GPX4. The effect of GPX4 inhibition on HR-proficient ovarian cancer was determined by CCK-8 assay and flow cytometry. Immunofluorescence and comet assays were used to reflect DNA dam-age. ROS production was measured using DCFH-DA and flow cytometry. The combination index of PARP inhibitors and RSL3 was calculated using CompuSyn software based on Chou-Talalay methodology. GPX4 inhibition confers HR-proficient ovarian cancer cells sensitive to PARPi due to ROS generation and oxidative stress caused by DNA double-strand breakage. The combina-tion of olaparib and niraparib with GPX4 inhibitor RSL3 also showed a synergistic effect. Combining GPX4 inhibition with PARP inhibitors resulted in a notable increase in DNA damage, ultimately causing the death of cancer cells with proficient HR pathways. Our findings may provide new therapeutic options for HR-proficient patients to benefit from PARP inhibitors and improve outcomes.

Microneedle patch capable of dual drug release for drug delivery to brain tumors.

Primary brain tumors are mostly managed using surgical resection procedures. Nevertheless, in certain cases, a thin layer of tumors may remain outside of the resection process due to the possibility of permanent injury; these residual tumors expose patients to the risk of tumor recurrence. This study has introduced the use of microneedle patches implanted after surgery with a dual-release mechanism for the administration of doxorubicin. The proposed patches possess the capability to administer drugs directly to the residual tumors and initiate chemotherapy immediately following surgical procedures. Three-dimensional simulation of drug delivery to residual tumors in the brain has been performed based on a finite element method. The impact of four important parameters on drug delivery has been investigated, involving the fraction of drug released in the burst phase, the density of microneedles on the patch, the length of microneedles, and the microvascular density of the tumor. The simulation findings indicate that lowering the fraction of drug released in the initial burst phase reduces the maximum average concentration, but the sustained release that continues for a longer period, increasing the bioavailability of free drug. However, the area under curve (AUC) for different release rates remains unchanged due to the fact that an identical dose of drug is supplied in each instance. By increasing the density of microneedles on the patch, concentration accumulation is provided over an extensive region of tumor, which in turn induces more cancer cell death. A comparative analysis of various lengths reveals that longer microneedles facilitate profound penetration into the tumor layers and present better therapeutic response due to extensive area of the tumor which is exposure to chemotherapeutic drugs. Furthermore, high microvascular density, as a characteristic of the tumor microenvironment, is shown to have a significant impact on the blood microvessels drainage of drugs and consequently lower therapeutic response outcome. Our approach offers a computational framework for creating localized drug delivery systems and addressing the challenges related to residual brain tumors.

Combining Mitomycin C with inhibition of BAD phosphorylation enhances apoptotic cell death in advanced cervical cancer

ObjectiveMitomycin C (MMC), a DNA-damaging chemotherapeutic, is commonly used clinically for recurrent cervical carcinoma (CC), either alone or in combination. MMC generates DNA damage resulting in CC cell death yet also induces increased AKT-BAD phosphorylation associated with drug resistance and reduced clinical benefit. The present study evaluates the efficacy of combined MMC and a BAD phosphorylation inhibitor in CC. MethodsThe association and function of phosphorylation of BAD on serine 99 (pBADS99) for cell survival of both MMC-resistant or sensitive-CC cells was explored. BAD was mutated to BADS99A to examine the requirement of BADS99 for CC cell survival and a novel small-molecule inhibitor of pBADS99 was utilized. Cell proliferation, survival, foci formation, and patient-derived organoids (PDOs) assays were utilized to determine efficacy, synergy and related mechanisms. ResultsMMC IC50 was positively correlated to the cell line pBADS99/BAD ratio. Increased BADS99 phosphorylation was observed in both MMC-sensitive or -resistant CC cells after MMC treatment. Inhibition of pBADS99 in CC cell lines produced synergistic apoptosis through BAD-mediated apoptotic pathways and enhanced DNA damage in response to MMC. The concurrent use of pharmacological inhibition of pBADS99 and MMC was synergistic, resulting in diminished cell viability and inducing apoptotic cell death in MMC-sensitive and -resistant CC cell lines or patient-derived organoids. ConclusionA combination of MMC with inhibition of BAD phosphorylation potentiated efficacy compared to single agent treatment. The potential further development of such strategies may provide outcome benefits to patients with CC.

Hydroxychloroquine loaded hollow apoferritin nanocages for cancer drug repurposing and autophagy inhibition

Hydroxychloroquine sulfate (HCQ) is currently being repurposed for cancer treatment. The antitumor mechanism of HCQ is inhibition of cellular autophagy, but its therapeutic potential is severely limited by poor solubility, lack of tumor targeting and lower cellular uptake. Therefore, utilization of human H-chain apoferritin (HFn) composed only of heavy subunits is an attractive approach for tumor targeting drug delivery. This study focused on pH-triggered encapsulation of HCQ within the inner cavity of HFn to form HFn@HCQ nanoparticles for tumor-targeted drug delivery. Characterization using a range of techniques has been used to confirm the successful establishment of HFn@HCQ. HFn@HCQ exhibited pH-responsive release behavior, with almost no drug release at pH 7.4, but 80% release at pH 5.0. Owing to its intrinsic binding to transferrin receptor 1 (TfR1), HFn@HCQ was significantly internalized through TfR1-mediated endocytosis, with a 4.4-fold difference of internalization amount across cell lines. Additionally, HFn@HCQ enhanced the antitumor effect against four different cancer cell lines when compared against HCQ alone, especially in TfR1 high-expressing cells, where the inhibitory effect was 3-fold higher than free HCQ. The autophagy inhibition of HFn@HCQ has been demonstrated, which is a major pathway to induce cancer cell death. According to current findings, HFn based drug delivery is a promising strategy to target and kill TfR1 overexpressing tumor cells.

A Review of the Efficacy of Nanomaterial-Based Natural Photosensitizers to Overcome Multidrug Resistance in Cancer.

Natural photosensitizers (PS) are compounds derived from nature, with photodynamic properties. Natural PSs have a similar action to that of commercial PSs, where cancer cell death occurs by necrosis, apoptosis, and autophagy through ROS generation. Natural PSs have garnered great interest over the last few decades because of their high biocompatibility and good photoactivity. Specific wavelengths could cause phytochemicals to produce harmful ROS for photodynamic therapy (PDT). However, natural PSs have some shortcomings, such as reduced solubility and lower uptake, making them less appropriate for PDT. Nanotechnology offers an opportunity to develop suitable carriers for various natural PSs for PDT applications. Various nanoparticles have been developed to improve the outcome with enhanced solubility, optical adsorption, and tumor targeting. Multidrug resistance (MDR) is a phenomenon in which tumor cells develop resistance to a wide range of structurally and functionally unrelated drugs. Over the last decade, several researchers have extensively studied the effect of natural PS-based photodynamic treatment (PDT) on MDR cells. Though the outcomes of clinical trials for natural PSs were inconclusive, significant advancement is still required before PSs can be used as a PDT agent for treating MDR tumors. This review addresses the increasing literature on MDR tumor progression and the efficacy of PDT, emphasizing the importance of developing new nano-based natural PSs in the fight against MDR that have the required features for an MDR tumor photosensitizing regimen.

An “Iron-phagy” nanoparticle inducing irreversible mitochondrial damages for antitumor therapy

Cellular iron is inseparably related with the proper functionalities of mitochondria for its potential to readily donate and accept electrons. Though promising, the available endeavors of iron chelation antitumor therapies have tended to be adjuvant therapies. Herein, we conceptualized and fabricated an “iron-phagy” nanoparticle (Dp44mT@HTH) capable of inducing the absolute devastation of mitochondria via inhibiting the autophagy-removal of impaired ones for promoting cancer cell death. The Dp44mT@HTH with hyaluronic acid (HA) as hydrophilic shell can specifically target the highly expressed CD44 receptors on the surface of 4T1 tumor cells. After internalization and lysosomal escape, the nanoparticle disassembles in response to the reactive oxygen species (ROS), subsequently releasing the iron chelator Dp44mT and autophagy-inhibitory drug hydroxychloroquine (HCQ). Dp44mT can then seize cellular Fe2+ to trigger mitochondrial dysfunction via respiratory chain disturbance, while HCQ not only lessens Fe2+ intake, but also impedes fusions of autophagosomes and lysosomes. Consequentially, Dp44mT@HTH induces irreversible mitochondrial impairments, in this respect creating a substantial toxic stack state that induces apoptosis and cell death. Initiating from the perspective of endogenous substances, this strategy illuminates the promise of iron depletion therapy via irreversible mitochondrial damage induction for anticancer treatment.

Combination of ionizing radiation and 2-thio-6-azauridine induces cell death in radioresistant triple negative breast cancer cells by downregulating CD151 expression.

Triple-negative breast cancer (TNBC) represents the most aggressive subtype of breast cancer and is frequently resistant to therapy, ultimately resulting in treatment failure. Clinical trials have demonstrated the potential of sensitizing radiation therapy (RT)-resistant TNBC through the combination of chemotherapy and RT. This study sought to explore the potential of CD151 as a therapy response marker in the co-treatment strategy involving ionizing radiation (IR) and the repurposed antiviral drug 2-Thio-6-azauridine (TAU) for sensitizing RT-resistant TNBC (TNBC/RR). The investigation encompassed a variety of assessments, including viability using MTT and LDH assays, cell proliferation through BrdU incorporation and clonogenic assays, cell cycle analysis via flow cytometry, cell migration using wound scratch and Boyden chamber invasion assays, DNA damage assessment through γH2AX analysis, apoptosis evaluation through acridine-orange and ethidium bromide double staining assays, as well as caspase 3 activity measurement using a colorimetric assay. CD151 expression was examined through ELISA, flow cytometryand RT-qPCR. The results showed a significant reduction in TNBC/RR cell viability following co-treatment. Moreover, the co-treatment reduced cell migration, induced apoptosis, downregulated CD151 expression, and increased caspase 3 activity in TNBC/RR cells. Additionally, CD151 was predicted to serve as a therapy response marker for co-treatment with TAU and IR. These findings suggest the potential of combination treatment with IR and TAU as a promising strategy to overcome RT resistance in TNBC. Furthermore, CD151 emerges as a valuable therapy response marker for chemoradiotherapy.

The DNA repair pathway as a therapeutic target to synergize with trastuzumab deruxtecan in HER2-targeted antibody–drug conjugate–resistant HER2-overexpressing breast cancer

BackgroundAnti-HER2 therapies, including the HER2 antibody–drug conjugates (ADCs) trastuzumab emtansine (T-DM1) and trastuzumab deruxtecan (T-DXd), have led to improved survival outcomes in patients with HER2-overexpressing (HER2+) metastatic breast cancer. However, intrinsic or acquired resistance to anti-HER2–based therapies remains a clinical challenge in these patients, as there is no standard of care following disease progression. The purpose of this study was to elucidate the mechanisms of resistance to T-DM1 and T-DXd in HER2+ BC patients and preclinical models and identify targets whose inhibition enhances the antitumor activity of T-DXd in HER2-directed ADC-resistant HER2+ breast cancer in vitro and in vivo.MethodsTargeted DNA and whole transcriptome sequencing were performed in breast cancer patient tissue samples to investigate genetic aberrations that arose after anti-HER2 therapy. We generated T-DM1 and T-DXd–resistant HER2+ breast cancer cell lines. To elucidate their resistance mechanisms and to identify potential synergistic kinase targets for enhancing the efficacy of T-DXd, we used fluorescence in situ hybridization, droplet digital PCR, Western blotting, whole-genome sequencing, cDNA microarray, and synthetic lethal kinome RNA interference screening. In addition, cell viability, colony formation, and xenograft assays were used to determine the synergistic antitumor effect of T-DXd combinations.ResultsWe found reduced HER2 expression in patients and amplified DNA repair–related genes in patients after anti-HER2 therapy. Reduced ERBB2 gene amplification in HER2-directed ADC–resistant HER2+ breast cancer cell lines was through DNA damage and epigenetic mechanisms. In HER2-directed ADC–resistant HER2+ breast cancer cell lines, our non-biased RNA interference screening identified the DNA repair pathway as a potential target within the canonical pathways to enhance the efficacy of T-DXd. We validated that the combination of T-DXd with ataxia telangiectasia and Rad3-related inhibitor, elimusertib, led to significant breast cancer cell death in vitro (P < 0.01) and in vivo (P < 0.01) compared to single agents.ConclusionsThe DNA repair pathways contribute to HER2-directed ADC resistance. Our data justify exploring the combination treatment of T-DXd with DNA repair–targeting drugs to treat HER2-directed ADC–resistant HER2+ breast cancer in clinical trials.

Plant‐Derived Phytochemicals and Their Nanoformulations for Inducing Programed Cell Death in Cancer

AbstractPhytochemicals are a diverse class of compounds found in various plant‐based foods and beverages that have displayed the capacity to exert powerful anticancer effects through the induction of programed cell death (PCD) in malignancies. PCD is a sophisticated process that maintains in upholding tissue homeostasis and eliminating injured or neoplastic cells. Phytochemicals have shown the potential to induce PCD in malignant cells through various mechanisms, including modulation of cell signaling pathways, regulation of reactive oxygen species (ROS), and interaction with critical targets in cells such as DNA. Moreover, recent studies have suggested that nanomaterials loaded with phytochemicals may enhance cell death in tumors, which can also stimulate antitumor immunity. In this review, a comprehensive overview of the current understanding of the anticancer effects of phytochemicals and their potential as a promising approach to cancer therapy, is provided. The impacts of phytochemicals such as resveratrol, curcumin, apigenin, quercetin, and some approved plant‐derived drugs, such as taxanes on the regulation of some types of PCD, including apoptosis, pyroptosis, anoikis, autophagic cell death, ferroptosis, and necroptosis, are discussed. The underlying mechanisms and the potential of nanomaterials loaded with phytochemicals to enhance PCD in tumors are also explained.

In Vivo Tracking and 3D Mapping of Cell Death in Regeneration and Cancer Using Trypan Blue.

Tracking cell death in vivo can enable a better understanding of the biological mechanisms underlying tissue homeostasis and disease. Unfortunately, existing cell death labeling methods lack compatibility with in vivo applications or suffer from low sensitivity, poor tissue penetration, and limited temporal resolution. Here, we fluorescently labeled dead cells in vivo with Trypan Blue (TBlue) to detect single scattered dead cells or to generate whole-mount three-dimensional maps of large areas of necrotic tissue during organ regeneration. TBlue effectively marked different types of cell death, including necrosis induced by CCl4 intoxication in the liver, necrosis caused by ischemia-reperfusion in the skin, and apoptosis triggered by BAX overexpression in hepatocytes. Moreover, due to its short circulating lifespan in blood, TBlue labeling allowed in vivo "pulse and chase" tracking of two temporally spaced populations of dying hepatocytes in regenerating mouse livers. Additionally, upon treatment with cisplatin, TBlue labeled dead cancer cells in livers with cholangiocarcinoma and dead thymocytes due to chemotherapy-induced toxicity, showcasing its utility in assessing anticancer therapies in preclinical models. Thus, TBlue is a sensitive and selective cell death marker for in vivo applications, facilitating the understanding of the fundamental role of cell death in normal biological processes and its implications in disease.

Induction of Ferroptosis by an Amalgam of Extracellular Vesicles and Iron Oxide Nanoparticles Overcomes Cisplatin Resistance in Lung Cancer.

Extracellular vesicles (EVs) hold potential as effective carriers for drug delivery, providing a promising approach to resolving challenges in lung cancer treatment. Traditional treatments, such as with the chemotherapy drug cisplatin, encounter resistance in standard cell death pathways like apoptosis, prompting the need to explore alternative approaches. This study investigates the potential of iron oxide nanoparticles (IONP) and EVs to induce ferroptosis-a regulated cell death mechanism-in lung cancer cells. We formulated a novel EV and IONP-based system, namely 'ExoFeR', and observed that ExoFeR demonstrated efficient ferroptosis induction, evidenced by downregulation of ferroptosis markers (xCT/SLC7A11 and GPX4), increased intracellular and mitochondrial ferrous iron levels, and morphological changes in mitochondria. To enhance efficacy, tumor-targeting transferrin (TF)-conjugated ExoFeR (ExoFeR TF ) was developed. ExoFeR TF outperformed ExoFeR, exhibiting higher uptake and cell death in lung cancer cells. Mechanistically, nuclear factor erythroid 2-related factor 2 (Nrf2)-a key regulator of genes involved in glutathione biosynthesis, antioxidant responses, lipid metabolism, and iron metabolism-was found downregulated in the ferroptotic cells. Inhibition of Nrf2 intracellular translocation in ExoFeR TF -treated cells was also observed, emphasizing the role of Nrf2 in modulating ferroptosis-dependent cell death. Furthermore, ExoFeR and ExoFeR TF demonstrated the ability to sensitize chemo-resistant cancer cells, including cisplatin-resistant lung cancer patient-derived tumoroid organoids. In summary, ExoFeR TF presents a promising and multifaceted therapeutic approach for combating lung cancer by intrinsically inducing ferroptosis and sensitizing chemo-resistant cells.

Biomimetic Functional Nanocomplexes for Photothermal Cancer Chemoimmunotheranostics

This study presents a novel multimodal cancer theranostic platform developed using tumor cell‐coated biomimetic carbon nanohorn (CNH) complexes that encapsulate the anticancer drug paclitaxel (PTX). This platform combines photothermal therapy, chemotherapy, and immunotherapy to fight against malignant colorectal cancer. These engineered nanocomplexes are designed to deliver sufficient PTX molecules into a targeted solid tumor in a light‐controllable manner while inducing significant photothermal and antitumor immune responses. The outstanding photothermal conversion property of the CNHs under near‐infrared light enables effective cancer cell ablation and awakening of cytotoxic immune responses. Tumor cell membrane‐coated CNHs show improved water dispersibility, immune evasion, and targeting capabilities alongside enhanced immune activation against tumors. The efficacy of the biomimetic functional CNH nanocomplexes is demonstrated through excellent tumor‐targeting, controlled drug‐releasing behavior, and induction of cancer cell death, contributing to a robust antitumor response. This study provides a promising approach to cancer treatment by integrating multiple therapeutic modalities into a single platform, potentially enhancing treatment efficacy to combat intractable cancer.

Clustering of the Membrane Protein by Molecular Self-Assembly Downregulates the Signaling Pathway for Cancer Cell Inhibition.

This work reports a cyclic peptide appended self-assembled scaffold that recognizes the membrane protein EGFR and arrests the EGFR signaling through multivalent interactions by assembly-induced aggregation. When incubated with cells, the oligomers of PAD-1 first recognize the overexpressed EGFR on cancer cell membranes for arresting EGFR, which then initiates cellular uptake through endocytosis. The accumulation of PAD-1 and EGFR in the lysosome results in the formation of nanofibers, leading to the lysosomal membrane permeabilization (LMP). These processes disrupt the homeostasis of EGFR and inhibit the downstream signaling transduction of EGFR for cancer cell survival. Moreover, LMP induced the release of protein aggregates that could generate endoplasmic reticulum (ER) stress, resulting in cancer cell death selectively. In vivo studies indicate the efficient antitumor efficiency of PAD-1 in tumor-bearing mice. As a first example, this work provides an alternative strategy for controlling protein behavior for tuning cellular events in living cells.

Targeting DNA damage repair mechanism by using RAD50-silencing siRNA nanoparticles to enhance radiotherapy in triple negative breast cancer

Radiotherapy (RT) is one of major therapeutic modalities in combating breast cancer. In RT, ionizing radiation is employed to induce DNA double-strand breaks (DSBs) as a primary mechanism that causes cancer cell death. However, the induced DNA damage can also trigger the activation of DNA repair mechanisms, reducing the efficacy of RT treatment. Given the pivotal role of RAD50 protein in the radiation-responsive DNA repair pathways involving DSBs, we developed a novel polymer-lipid based nanoparticle formulation containing RAD50-silencing RNA (RAD50-siRNA-NPs) and evaluated its effect on the RAD50 downregulation as well as cellular and tumoral responses to ionizing radiation using human triple-negative breast cancer as a model. The RAD50-siRNA-NPs successfully preserved the activity of the siRNA, facilitated its internalization by cancer cells via endocytosis, and enabled its lysosomal escape. The nanoparticles significantly reduced RAD50 expression, whereas RT alone strongly increased RAD50 levels at 24 h. Pretreatment with RAD50-siRNA-NPs sensitized the cancer cells to RT with ∼2-fold higher level of initial DNA DSBs as determined by a γH2AX biomarker and a 2.5-fold lower radiation dose to achieve 50 % colony reduction. Intratumoral administration of RAD50-siRNA-NPs led to a remarkable 53 % knockdown in RAD50. The pretreatment with RAD50-siRNA-NPs followed by RT resulted in approximately a 2-fold increase in DNA DSBs, a 4.5-fold increase in cancer cell apoptosis, and 2.5-fold increase in tumor growth inhibition compared to RT alone. The results of this work demonstrate that RAD50 silencing by RAD50-siRNA-NPs can disrupt RT-induced DNA damage repair mechanisms, thereby significantly enhancing the radiation sensitivity of TNBC MDA-MB-231 cells in vitro and in orthotopic tumors as measured by colony forming and tumor regrowth assays, respectively.

Targeting ERK-MYD88 interaction leads to ERK dysregulation and immunogenic cancer cell death

The quest for targeted therapies is critical in the battle against cancer. The RAS/MAP kinase pathway is frequently implicated in neoplasia, with ERK playing a crucial role as the most distal kinase in the RAS signaling cascade. Our previous research demonstrated that the interaction between ERK and MYD88, an adaptor protein in innate immunity, is crucial for RAS-dependent transformation and cancer cell survival. In this study, we examine the biological consequences of disrupting the ERK-MYD88 interaction through the ERK D-recruitment site (DRS), while preserving ERK’s kinase activity. Our results indicate that EI-52, a small-molecule benzimidazole targeting ERK-MYD88 interaction induces an HRI-mediated integrated stress response (ISR), resulting in immunogenic apoptosis specific to cancer cells. Additionally, EI-52 exhibits anti-tumor efficacy in patient-derived tumors and induces an anti-tumor T cell response in mice in vivo. These findings suggest that inhibiting the ERK-MYD88 interaction may be a promising therapeutic approach in cancer treatment.

Induction of Paraptotic Cell Death in Cancer Cells by Triptycene-Peptide Hybrids and the Revised Mechanism of Paraptosis II.

In previous work, we reported on iridium(III) (Ir(III)) complex-peptide hybrids as amphiphilic conjugates (IPH-ACs) and triptycene-peptide hybrids as amphiphilic conjugates (TPH-ACs) and found that these hybrid compounds containing three cationic KK(K)GG peptide units through C6-C8 alkyl linkers induce paraptosis II, which is one of the nonapoptotic programmed cell death (PCD) types in Jurkat cells and different from previously reported paraptosis. The details of that study revealed that the paraptosis II induced by IPH-ACs (and TPH-ACs) proceeds via a membrane fusion or tethering of the endoplasmic reticulum (ER) and mitochondria, and Ca2+ transfer from the ER to mitochondria, which results in a loss of mitochondrial membrane potential (ΔΨm) in Jurkat cells. However, the detailed mechanistic studies of paraptosis II have been conducted only in Jurkat cells. In the present work, we decided to conduct mechanistic studies of paraptosis II in HeLa-S3 and A549 cells as well as in Jurkat cells to study the general mechanism of paraptosis II. Simultaneously, we designed and synthesized new TPH-ACs functionalized with peptides that contain cyclohexylalanine, which had been reported to enhance the localization of peptides to mitochondria. We found that TPH-ACs containing cyclohexylalanine promote paraptosis II processes in Jurkat, HeLa-S3 and A549 cells. The results of the experiments using fluorescence Ca2+ probes in mitochondria and cytosol, fluorescence staining agents of mitochondria and the ER, and inhibitors of paraptosis II suggest that TPH-ACs induce Ca2+ increase in mitochondria and the membrane fusion between the ER and mitochondria almost simultaneously, suggesting that our previous hypothesis on the mechanism of paraptosis II should be revised.