Enhanced Tumor Cell Apoptosis Research Articles

Olaparib Enhances the Efficacy of Third-Generation Oncolytic Adenoviruses Against Glioblastoma by Modulating DNA Damage Response and p66shc-Induced Apoptosis.

Patients with glioblastoma multiforme (GBM) do not benefit from current cancer treatments, and their prognosis is dismal. This study aimed to investigate the potential synergistic effects of TS-2021, a third-generation oncolytic adenovirus, combined with the PARP inhibitor olaparib in GBM. TS-2021's impact on p66shc-induced apoptosis, DNA damage response, and poly (ADP-ribose) polymerase (PARP) activation was evaluated in GBM cells. The synergistic effect of TS-2021 and olaparib was examined in GBM cell lines and an immunocompetent mouse model of GBM. Mechanistic studies focused on the role of p66shc phosphorylation in the observed effects. TS-2021 triggered p66shc-induced apoptosis, DNA damage response, and PARP activation. The combination of TS-2021 and olaparib synergistically increased cell apoptosis and DNA damage and reduced PARP expression compared to monotherapy. Olaparib promoted TS-2021 replication and release in GBM cells. Mechanistically, olaparib combined with TS-2021 upregulated p66shc phosphorylation, enhancing tumor cell apoptosis. Invivo, the combination therapy inhibited tumor growth and prolonged survival, confirming the synergistic effect. This study is the first to suggest that TS-2021 sensitizes GBM cells with wild-type BRCA1/2 to olaparib. The combination of TS-2021 and olaparib shows a synergistic therapeutic effect against GBM, providing a promising treatment strategy.

BCL2 expression is enriched in advanced prostate cancer with features of lineage plasticity.

The widespread use of potent androgen receptor signaling inhibitors (ARSIs) has led to an increasing emergence of AR-independent castration-resistant prostate cancer (CRPC), typically driven by loss of AR expression, lineage plasticity, and transformation to prostate cancers (PCs) that exhibit phenotypes of neuroendocrine or basal-like cells. The anti-apoptotic protein BCL2 is upregulated in neuroendocrine cancers and may be a therapeutic target for this aggressive PC disease subset. There is an unmet clinical need, therefore, to clinically characterize BCL2 expression in metastatic CRPC (mCRPC), determine its association with AR expression, uncover its mechanisms of regulation, and evaluate BCL2 as a therapeutic target and/or biomarker with clinical utility. Here, using multiple PC biopsy cohorts and models, we demonstrate that BCL2 expression is enriched in AR-negative mCRPC, associating with shorter overall survival and resistance to ARSIs. Moreover, high BCL2 expression associates with lineage plasticity features and neuroendocrine marker positivity. We provide evidence that BCL2 expression is regulated by DNA methylation, associated with epithelial-mesenchymal transition, and increased by the neuronal transcription factor ASCL1. Finally, BCL2 inhibition had antitumor activity in some, but not all, BCL2-positive PC models, highlighting the need for combination strategies to enhance tumor cell apoptosis and enrich response.

In-situ activated arsenic-molybdenum dual-prodrug nanocomplexes for glutathione-depletion enhanced photothermal/chemotherapy against triple-negative breast cancer

Arsenic trioxide, a traditional chemotherapeutic agent, has limitations in clinical application due to its nonspecific delivery and severe systemic toxicity. To address this challenge, we have capitalized on the promising potential of molybdenum-based materials for tumor diagnosis and treatment. We developed a novel multifunctional arsenic-molybdenum dual-prodrug nanocomposite delivery system (AsMo-NCM) by integrating arsenic compounds with molybdenum compounds. This system leverages elevated glutathione (GSH) levels within tumors for specific activation. Within the tumor microenvironment, the system converts Mo(VI) to the more active Mo(V), enabling combined photothermal therapy and photoacoustic imaging for comprehensive diagnosis and treatment. Furthermore, low-toxicity arsenic(V) is converted into highly toxic trivalent arsenic within the high-GSH tumor microenvironment, thereby enhancing tumor cell apoptosis, reducing toxicity to normal tissues, and synergistically improving treatment outcomes. In addition, AsMo-NCM can be biodegraded and rapidly excreted, reducing concerns about their long-term presence and possible toxic effects. The combination of these approaches maximizes GSH depletion, thereby enhancing the synergistic photothermal/chemotherapy effect of AsMo-NCM for precise and effective tumor treatment, thus offering promising prospects for cancer therapy.

Magnetothermal-activated gene editing strategy for enhanced tumor cell apoptosis

Precise and effective initiation of the apoptotic mechanism in tumor cells is one of the most promising approaches for the treatment of solid tumors. However, current techniques such as high-temperature ablation or gene editing suffer from the risk of damage to adjacent normal tissues. This study proposes a magnetothermal-induced CRISPR-Cas9 gene editing system for the targeted knockout of HSP70 and BCL2 genes, thereby enhancing tumor cell apoptosis. The magnetothermal nanoparticulate platform is composed of superparamagnetic ZnCoFe2O4@ZnMnFe2O4 nanoparticles and the modified polyethyleneimine (PEI) and hyaluronic acid (HA) on the surface, on which plasmid DNA can be effectively loaded. Under the induction of a controllable alternating magnetic field, the mild magnetothermal effect (42℃) not only triggers dual-genome editing to disrupt the apoptosis resistance mechanism of tumor cells but also sensitizes tumor cells to apoptosis through the heat effect itself, achieving a synergistic therapeutic effect. This strategy can precisely regulate the activation of the CRISPR-Cas9 system for tumor cell apoptosis without inducing significant damage to healthy tissues, thus providing a new avenue for cancer treatment.

PH-responsive drug-loaded peptides enhance drug accumulation and promote apoptosis in tumor cells

The efficacy of chemotherapeutic drugs in tumor treatment is limited by their toxicity and side effects due to their inability to selectively accumulate in tumor tissue. In addition, chemotherapeutic agents are easily pumped out of tumor cells, resulting in their inadequate accumulation. To overcome these challenges, a drug delivery system utilizing the amphiphilic peptide Pep1 was designed. Pep1 can self-assemble into spherical nanoparticles (PL/Pep1) and encapsulate paclitaxel (PTX) and lapatinib (LAP). PL/Pep1 transformed into nanofibers in an acidic environment, resulting in longer drug retention and higher drug concentrations within tumor cells. Ultimately, PL/Pep1 inhibited tumor angiogenesis and enhanced tumor cell apoptosis. The use of shape-changing peptides as drug carriers to enhance cancer cell apoptosis is promising.

Copper-coordinated nanoassemblies based on photosensitizer-chemo prodrugs and checkpoint inhibitors for enhanced apoptosis-cuproptosis and immunotherapy

Cuproptosis is a recently identified copper-dependent form of nonapoptotic cell death and holds great prospect in cancer treatment. One of the most intriguing aspects of cuproptosis is its ability to synergize with apoptosis-based cancer treatments. Herein, we presented a novel approach using copper-coordinated nanoassemblies (CCNAs) that were constructed by incorporating a photosensitizer Zinc Phthalocyanine (ZnPc)-chemotherapeutic (DOX) prodrug with a thioketal (TK) spacer and an IDO inhibitor (1-methyl tryptophan, 1-MT) as building blocks for Cu2+-coordination self-assembly to achieve combinational apoptosis-cuproptosis and immunotherapy. Upon NIR laser irradiation, the ZnPc component of CCNAs exhibited a photodynamic effect that generated reactive oxygen species (ROS). This triggered the release of DOX, leading to enhanced tumor cell apoptosis. Additionally, the presence of Cu2+ in the CCNAs not only enhanced the photodynamic process by catalyzing oxygen generation but also promoted the aggregation of toxic mitochondrial proteins, leading to cell cuproptosis. Importantly, the intensified cuproptosis-apoptosis effect triggered an immunogenic cell death (ICD) response. The released 1-MT complemented this response by reversing the immunosuppressive tumor microenvironment (ITM), synergistically amplifying anti-tumor immunity and suppressing the growth of primary and distant tumors. The findings of this study provide a new perspective on potential cancer treatments based on cuproptosis-apoptosis synergistic immunotherapy and stimulate further research in the design of advanced metal-coordinated nanomedicines. Statement of significanceThe combination of cuproptosis and apoptosis that act with different mechanisms holds enormous potential in cancer treatment. Here, copper-coordinated nanoassemblies (CCNAs) based on photosensitizer-chemo prodrugs and checkpoint inhibitors were constructed for mediating cuproptosis-apoptosis and subsequently promoting cancer immunotherapy. CCNAs not only promoted the photodynamic effect and activation of chemotherapy through catalyzing the generation of oxygen but also induced toxic mitochondrial protein aggregation, leading to cell cuproptosis. These synergistic antitumor effects triggered robust immune responses with the aid of immune checkpoint blockade, almost eradicating primary tumors and inhibiting distant tumors by around 83 % without systemic toxicity.

BRD7 suppresses tumor chemosensitivity to CHK1 inhibitors by inhibiting USP1-mediated deubiquitination of CHK1

Checkpoint kinase 1 (CHK1), a key effector in the cellular response to DNA lesions, is a crucial component of all cell cycle checkpoints. Recent reports have revealed that CHK1 is highly expressed in numerous cancer types in the clinical settings. However, the mechanisms underlying the regulation of CHK1 expression in tumor cells remain unclear. Here, we report that CHK1 is negatively regulated by the bromodomain-containing protein 7 (BRD7). Specifically, BRD7 silencing increased CHK1 (but not CHK2) expression at both mRNA and protein levels, in a p53-independent manner in multiple tumor cell lines. Furthermore, BRD7 silencing stabilized CHK1 via reducing its ubiquitination. Mechanistically, BRD7 knockdown not only increased the levels of USP1, a deubiquitinase for CHK1, but also promoted the interaction between CHK1 and USP1, subsequently enhancing the de-ubiquitination of CHK1. USP1 knockdown abrogated BRD7 silencing-induced CHK1 induction. Biologically, the increased expression of CHK1 in tumor cells caused by BRD7 silencing significantly increased cell sensitivity to CHK1 inhibitors by enhancing tumor cell apoptosis, and this effect was reversed by the simultaneous knockdown of CHK1 or USP1. Taken together, our findings suggest that BRD7 is a potential genetic or drug target that may help to improve the efficacy of chemotherapeutic drugs targeting CHK1 in combinatorial therapy.

Coaxial electrostatic spray-based preparation of localization missile liposomes on a microfluidic chip for targeted treatment of triple-negative breast cancer

Due to triple-negative breast cancer (TNBC) lacking specific targets for efficient therapies, nanoparticles have been widely developed to enhance efficacy and reduce the toxicity of chemotherapeutics. We prepared unique liposomes containing PTX and DOX by microfluidics-based coaxial electrostatic spray method, which have a uniform particle size, high drug loading capacity, and good stability. Meanwhile, the cRGD peptide was fused with the lipid membrane to form PTX/DOX@cRGD-Lipo, which played a GPS role in locating tumor neovascularization and further targeting TNBC cells where both overexpress αvβ3. The PTX/DOX@cRGD-Lipo showed synergistic anti-tumor activity of double drugs and enhanced tumor cell apoptosis. Fluorescence microscopy and flow cytometry showed that the co-loaded targeted liposomes could be effectively absorbed by MDA-MB-231 and 4T1 cells and then released the content. In addition, the PTX/DOX@cRGD-Lipo presented excellent targeting biodistribution in vivo and a higher tumor growth inhibition rate in the orthotopic tumor mouse model. All results suggested that the double drug-loaded targeted liposome could be a promising treatment modality for TNBC.

Abstract 2784: JW-1-283 inhibits melanoma tumor growth via the stabilization of p53 pathway

Abstract Melanoma is the most lethal skin cancer, with the increasing incidence in the past decade. Despite the significant advancements in immune therapy and targeted therapy, the overall prognosis for metastatic melanoma remains unsatisfactory. TP53 is a tumor suppressor, but its wildtype is inactivated in about 90% of melanoma. Since activated p53 can promote cancer cell apoptosis and thus effectively inhibit tumor growth and tumor metastasis, reactivation of p53 is considered a promising strategy for cancer therapy. Herein, we report a recently developed small molecule compound, JW-1-283, targeting the interactions between MDM2 E3 ubiquitin-protein ligase and p53 protein. In vitro, JW-1-283 showed potent cytotoxicity against A375 melanoma cell line (IC50 2.2±0.3 μM) which has wildtype p53, but its potency is substantially reduced in two other melanoma cell lines with either p53 mutation (M14) or p53 null (RPMI-7951) status. Treatment with JW-1-283 significantly dose-dependently reduced the stemness in A375 melanoma cells, as indicated by low numbers of colony formation, impaired tumor sphere formation abilities, and inhibition of cancer cell migration. Mechanistically, JW-1-283 disrupts the p53-MDM2 interaction, prevents p53 and MDM2 degradation in the existence of cycloheximide, and induces p38 and p53 phosphorylation in the apoptotic pathway. Genetic knockdown of p38 by siRNA further confirmed that the stabilized p53 could be subsequently phosphorylated by p38, leading to induced apoptosis as well as S phase cell cycle arrest. In vivo, when A375 tumors grown in NSG mice were treated with 7.5 mg/kg of JW-1-283 intraperitoneally every other day for a consecutive of 16 days, significant inhibition of tumor growth was observed, along with decreased tumor cell proliferation, tumor angiogenesis, and enhanced tumor cell apoptosis. In summary, this work provides the initial proof-of-concept of developing the JW-1-283 scaffold as a potential strategy for advanced melanoma, which inhibits tumor growth by activating the p53 signaling pathway. Citation Format: Yang Xie, Kelli Hartman, Zhongzhi Wu, Wei Li. JW-1-283 inhibits melanoma tumor growth via the stabilization of p53 pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2784.

Green Tea Catechin Potentiating Doxorubicine Effects against BE(2)C Neuroblastoma Cells In Vitro

Background: Neuroblastoma (NB), a malignant sympathetic nervous system cancer, is the second most common type of pediatric tumor. Increasing the number of NB death emerges to design a new strategy for NB treatment. Nowadays, the development of natural compounds has gradually increased due to their ability to apoptosis induction. Tea catechin, a flavonoid compound, is one of the natural combinations which inhibit tumor growth and enhance tumor cell apoptosis. In the current study, the effects of pure catechin, doxorubicin (DOX), and their combination on a cellular model of NB [BE(2)C cells] are perused. (NB) a malignant sympathetic nervous system cancer is the second most common type of pediatric tumor. Increasing the number of NB death emerges to design a new strategy for NB treatment. Nowadays, the development of natural compounds has gradually increased due to their ability to apoptosis induction. Tea catechin, a flavonoid compound, is one of the natural combinations which inhibit tumor growth and enhance tumor cell apoptosis. Objectives: In the current study, the effects of pure catechin, doxorubicin (DOX), and their combination on a cellular model of NB [BE(2)C cells] are perused. Methods: The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was done to assess a response dose for each drug. Fluorescent Microscopic and cell cycle analyses were performed for apoptosis detection. Finally, Colony formation was performed to examine cell migration and invasion. Results: The MTT assay showed that catechin and DOX treatment inhibited the viability of the cells while the combination of their ineffective doses had more cytotoxic effects. However, these treatments could not inhibit the cell growth of the normal human fibroblast. Moreover, this combination reduced cell attachment, chromatin fragmentation, and G/S arrest in the cell cycle. The clonogenic assay demonstrated that colony size and numbers obviously reduced after ten days; therefore, Catchin and its combination with DOX suppressed cell capacities of clone formation and migration. Conclusions: These results suggest that catechin, DOX, and their combination may inhibit the proliferation, invasion, and migration of BE(2)C Neuroblastoma cells in vitro while inducing cell apoptosis by arresting the cell cycle.

C-Src inhibitor PP2 inhibits head and neck cancer progression through regulation of the epithelial-mesenchymal transition.

Head and neck squamous cell carcinoma (HNSCC) is one of the most common cancer, causing considerable mortality and morbidity worldwide. Although HNSCC management has been extensively studied, the treatment outcomes have not improved - the 5-year survival rate of patients with HNSCC is 40%. Recent studies on the development of a novel HNSCC treatment have highlighted proto-oncogene tyrosine-protein kinase Src (c-Src) as one of the major therapeutic targets. However, the clinical efficacy of c-Src inhibitors against HNSCC was not comparable to that obtained in vitro. Furthermore, the molecular mechanisms underlying the efficacy of c-Src inhibitors remain elusive. In this study, we assessed the efficacy of 4-amino-5-(4-chlorophenyl)-7-(dimethylethyl)pyrazolo[3,4-d] pyrimidine (PP2), a selective c-Src inhibitor on HSNCC. Nine HNSCC cell lines (SNU1041, Fraud, SNU46, SNU1076, SNU899, SCC1483, YD15, YD9, and YD10-) were screened, and the effects of PP2 were evaluated using wound healing, apoptosis, and invasion assays. Western blot analysis of downstream markers was conducted to assess the specific mechanism of action of PP2 in HNSCC. The therapeutic efficacy of PP2 was further evaluated in xenograft mice. PP2 reduced tumor cell growth both in vitro and in vivo. Furthermore, it enhanced tumor cell apoptosis in cell lines and prevented metastasis in mice. PP2 also regulated the epithelial-mesenchymal transition pathway downstream of c-Src. More specifically, in SCC1483 and YD15PP2 HNSCC cell lines, PP2 exposure downregulated Erk, Akt/Slug, and Snail but upregulated E-cadherin. These results suggest that PP2 inhibits cell growth and progression in HNSCC by regulating the epithelial-mesenchymal transition pathway.

Abstract 1068: Anti-DR5 agonist IgM antibody IGM-8444 combined with SMAC mimetic birinapant induces strong synergistic tumor cytotoxicity

Abstract Apoptosis is induced through extrinsic and intrinsic signaling pathways. Extrinsic apoptosis can be activated through multimerization of death receptor 5 (DR5), a tumor necrosis factor (TNF) receptor family member highly expressed in many cancers. However, cellular resistance mechanisms within the intrinsic pathway may limit DR5 activity, including inhibitor of apoptosis proteins (IAPs) that block caspase activity or promote pro-survival NFκB signaling. Second mitochondria-derived activator of caspases (SMAC) is an endogenous bivalent IAP antagonist. Birinapant, a bivalent SMAC mimetic that binds and degrades IAPs, has been evaluated through Phase 2, demonstrating good safety and on target activity but minimal efficacy as a monotherapy. We hypothesized that simultaneously targeting the extrinsic apoptotic pathway with IGM-8444, an anti-DR5 multivalent IgM agonist, and the intrinsic apoptotic pathway with birinapant could enhance tumor cell apoptosis. Human cancer cell lines including triple negative breast cancer (TNBC), head and neck, ovarian, colorectal, lung, and sarcomas, were screened for sensitivity to IGM-8444 and birinapant combination. Strong synergistic cytotoxicity was observed in vitro in 36/45 (80%) cancer cell lines, as measured by both Bliss synergy score and maximal killing. IGM-8444 and birinapant combination also induced synergistic cytotoxicity in cells with acquired resistance to DR5 agonist antibodies. By contrast, IGM-8444 and birinapant did not kill primary human hepatocytes in vitro, demonstrating the potential clinical safety for this combination. In vivo, the IGM-8444 and birinapant combination dose-dependently reduced tumor growth in a MDA-MB-231 TNBC model, with 8/10 tumor-free mice at the highest dose of birinapant tested. By comparison, birinapant combination with an anti-DR5 IgG agonist showed a modest response. IGM-8444 and birinapant also showed significant anti-tumor responses in additional cell line and patient-derived xenograft models, including 7/9 tumor-free animals in a HT-1080 fibrosarcoma model and 9/10 complete responses in a EBC-1 lung squamous cell lung carcinoma model. Lastly, pharmacodynamic biomarkers including cIAP1 degradation, caspase activation, and caspase-cleaved cytokeratin 18 in tumor and serum correlated with anti-tumor response. In summary, combined targeting of the extrinsic and intrinsic apoptotic pathways with IGM-8444 and birinapant respectively enhances tumor cytotoxicity in multiple preclinical models. The combination of IGM-8444 with birinapant is currently under evaluation in a Phase 1 study in patients with relapsed and/or refractory solid cancers (NCT04553692). Citation Format: Beatrice T. Wang, Melanie Desbois, Susan E. Calhoun, Thomas J. Matthew, Poonam Yakkundi, Ling Wang, Xingjie Chen, Tasnim Kothambawala, Miho Oyasu, Maya F. Kotturi, Genevive Hernandez, Xiaohan Liu, Marvin S. Peterson, Eric W. Humke, Bruce A. Keyt, Angus M. Sinclair. Anti-DR5 agonist IgM antibody IGM-8444 combined with SMAC mimetic birinapant induces strong synergistic tumor cytotoxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1068.

Exosome-liposome hybrid nanoparticle codelivery of TP and miR497 conspicuously overcomes chemoresistant ovarian cancer

BackgroundAlthough cisplatin-based chemotherapy has been used as the first-line treatment for ovarian cancer (OC), tumor cells develop resistance to cisplatin during treatment, causing poor prognosis in OC patients. Studies have demonstrated that overactivation of the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway is involved in tumor chemoresistance and that overexpression of microRNA-497 (miR497) may overcome OC chemotherapy resistance by inhibiting the mTOR pathway. However, the low transcriptional efficiency and unstable chemical properties of miR497 limit its clinical application. Additionally, triptolide (TP) was confirmed to possess a superior killing effect on cisplatin-resistant cell lines, partially through inhibiting the mTOR pathway. Even so, the clinical applications of TP are restricted by serious systemic toxicity and weak water solubility.ResultsHerein, whether the combined application of miR497 and TP could further overcome OC chemoresistance by synergically suppressing the mTOR signaling pathway was investigated. Bioinspired hybrid nanoparticles formed by the fusion of CD47-expressing tumor exosomes and cRGD-modified liposomes (miR497/TP-HENPs) were prepared to codeliver miR497 and TP. In vitro results indicated that the nanoparticles were efficiently taken up by tumor cells, thus significantly enhancing tumor cell apoptosis. Similarly, the hybrid nanoparticles were effectively enriched in the tumor areas and exerted significant anticancer activity without any negative effects in vivo. Mechanistically, they promoted dephosphorylation of the overactivated PI3K/AKT/mTOR signaling pathway, boosted reactive oxygen species (ROS) generation and upregulated the polarization of macrophages from M2 to M1 macrophages.ConclusionOverall, our findings may provide a translational strategy to overcome cisplatin-resistant OC and offer a potential solution for the treatment of other cisplatin-resistant tumors.Graphical

Oncolytic adenovirus and gene therapy with EphA2-BiTE for the treatment of pediatric high-grade gliomas

BackgroundPediatric high-grade gliomas (pHGGs) are among the most common and incurable malignant neoplasms of childhood. Despite aggressive, multimodal treatment, the outcome of children with high-grade gliomas has not significantly improved...

Injectable Hyaluronic Acid Hydrogel for the Co-Delivery of Gemcitabine Nanoparticles and Cisplatin for Malignant Ascites Therapy.

Malignant ascites indicate the presence of malignant cells in the peritoneal cavity that lower patient survival and reduce quality of life. Current chemotherapy regimens suffer from the dilution of ascites and rapid metabolism limiting their therapeutic efficacy. The storage and sustained release of drugs at the tumor site represents a promising strategy to improve drug efficacy. The aim of this study was to develop injectable hyaluronic acid hydrogel containing polymeric gemcitabine nanoparticles and cisplatin for the local treatment of malignant ascites through a dual sustained drug release pattern. Cell uptake assays showed that the drug-loaded nanoparticles readily entered tumor cells. Apoptosis and cell cycle analysis showed that the hydrogel system could enhance tumor cell apoptosis and arrest more cells in the G1 phase. In vivo experiments indicated that mice treated with the drug-loaded hydrogels manifested the most significant efficacy in ascites volume, tumor nodules, body weight, abdominal circumference, and survival. The expression of Ki-67 and CD31 also significantly decreased compared with other groups, indicative of anti-tumor activity. In addition, intraperitoneal administration of the hydrogel system led to no significant damage to vital organs. These findings confirm the clinical potential of the drug-loaded hydrogel system for the treatment of malignant ascites.

The Antimicrobial Peptide, Nisin, Synergistically Enhances the Cytotoxic and Apoptotic Effects of Rituximab Treatment on Human Burkitt's Lymphoma Cell Lines.

Non-Hodgkin's lymphomas comprise the most common hematological cancers worldwide and consist of a heterogenous group of malignancies affecting the lymphoid system. Treatment of non-Hodgkin's lymphoma has been significantly enhanced with the addition of Rituximab to the standard chemotherapy regimen. However, even with the advancement of treatment patients continue to relapse and develop resistance to Rituximab, rendering subsequent treatments unsuccessful. The use of novel drugs with unique antitumor mechanisms has gained considerable attention. In this study, we explored the in vitro anti-cancer effects of the combined therapy of Rituximab and Nisin on human Burkitt's lymphoma cells. The human Burkitt's lymphoma cells lines, Raji and Daudi, were treated with Nisin, Rituximab, or a combination of the two agents at various concentrations. Cytotoxicity following treatment was determined using cell viability assay. The degree of apoptosis was verified via flow cytometric analysis using FITC annexin V/PI staining. Our findings show that the combined treatment of Rituximab and Nisin results in a more significant reduction in the survival of Raji and Daudi Burkitt's lymphoma cells, compared to Nisin or Rituximab treatment alone. Additionally, our results indicate that Nisin can induce a significant degree of apoptosis in the Burkitt's lymphoma cells compared to the negative controls. However, the addition of Nisin to the Rituximab treatment synergistically enhances the apoptotic antitumor effect. This study demonstrates the synergistic antitumor effect of Nisin treatment in vitro to enhance tumor cell apoptosis and the potential value of Nisin as an adjunct therapy in the treatment of lymphoma.

Vitexin attenuates epithelial ovarian cancer cell viability and motility in vitro and carcinogenesis in vivo via p38 and ERK1/2 pathways related VEGFA.

BackgroundEpithelial ovarian cancer (EOC) is the most common type of ovarian tumor, however, effective treatment does not currently exist for this condition. This study evaluated the role of vitexin in mitigating EOC both in vitro and in vivo.MethodSKOV-3 cells were used for in vitro experimentation. Xenotransplantation mouse models were set up by subcutaneously injecting mice with SKOV-3 cells. CCK8 was used to screen the optimal dose in vitro. Cell proliferation, invasion, number of microtubule nodules and apoptosis were respectively detected by colony formation assay, transwell assay, microtubule formation assay and flow cytometry. TUNEL and immunohistochemistry were used to detect tissues apoptosis and VEGF content. Western blot assay was used to detect the expression of Ki67, caspase-3, VEGFA, VEGFR2, ERK1/2 and p38.ResultsIn vitro experiment, compared with the control group, 10 µL of vitexin significantly reduced Ki67 levels and enhanced tumor cell apoptosis rate. Additionally, the colony forming rate, invasive cells per field, and number of nodes/HPF in vitexin treated group decreased dramatically. The result of western blot showed that levels of p-p38/p38 and p-ERK1/2/ERK1/2 also noticeably decreased. In vivo experiment, 40 mg/kg of vitexin significantly inhibited tumor growth. In addition, vitexin significantly enhanced the percentage of tissues apoptosis, which was accompanied by a decrease in the percentage of VEGF-positive cells.ConclusionsVitexin decreased the proliferation and invasion of SKOV-3 cells and noticeably reduced tumor growth. These findings suggest that vitexin could be a promising therapy for EOC.

Abstract 518: Agonistic Death Receptor 5 (DR5) IgM antibody IGM-8444 induces tumor cell apoptosis in vitro and in vivo and has a favorable in vitro safety profile

Abstract Death receptor 5 (DR5) is a member of the tumor necrosis factor (TNF) receptor superfamily that binds TNF-related apoptosis inducing ligand (TRAIL) to induce receptor trimerization and activate extrinsic apoptotic pathways. DR5 is expressed on a broad range of solid tumors as well as leukemias and lymphomas and has been targeted therapeutically with DR5 IgG antibodies and recombinant TRAIL agonists. However, agonistic IgG antibodies and TRAIL molecules targeting DR5 have been largely unsuccessful in clinical trials either in monotherapy or combination studies with chemotherapy due to insufficient receptor clustering to induce apoptotic pathways and/or due to very short half-life. Therefore, several new approaches have been taken to develop multivalent receptor DR5 agonists to enhance tumor cell apoptosis. We have taken the approach to efficiently cluster DR5 with multivalent IgM antibodies that contain 10 to 12 binding sites to DR5. First, we converted five agonistic IgG antibodies into the IgM antibody format and evaluated them using in vitro cell killing assays with colorectal cancer cell line Colo205 and compared them to IgG antibodies with the same binding domains. In all cases, we found the DR5 IgM antibodies significantly enhanced cellular cytotoxicity, resulting in at least 5,000 fold increased potency compared to IgGs. We have further developed a pentameric IgM antibody, IGM-8444, which has 10 binding sites specific for DR5 and efficiently triggers tumor cell apoptosis. In vitro tumor cell cytotoxicity screening identified IGM-8444 sensitive cell lines across 17 solid and hematologic cancer indications. IGM-8444 was efficacious as a monotherapy in both CDX and PDX preclinical mouse tumor xenograft models with complete and durable tumor regressions observed in a gastric PDX that expressed moderate levels of DR5 by immunohistochemistry. The combination of IGM-8444 with chemotherapeutic agents enhanced the cytotoxicity in several IGM-8444 resistant cell lines in vitro. IGM-8444 also combined well with standard-of-care therapies (e.g. irinotecan) in vivo, leading to enhanced efficacy. A significant challenge to the clinical development of multivalent DR5 agonists has been on-target liver toxicity. However, IGM-8444 had a favorable in vitro safety profile, with little/no in vitro cytotoxicity observed using primary human hepatocytes at concentrations >10,000 fold above the cytotoxicity EC50 observed in Colo205 cytotoxicity assays. Taken together, these data support the clinical development of IGM-8444 for the potential treatment of both solid and hematologic malignancies and an IND is projected to be filed in 2020. Citation Format: Beatrice Wang, Tasnim Kothambawala, Ling Wang, Bing Shan, Hai Lu, Ramesh Baliga, Marvin Peterson, Angus Sinclair, Bruce Keyt. Agonistic Death Receptor 5 (DR5) IgM antibody IGM-8444 induces tumor cell apoptosis in vitro and in vivo and has a favorable in vitro safety profile [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 518.

MEK blockade overcomes the limited activity of palbociclib in head and neck cancer.

Head and neck cancer (HNC) is characterized with multiple aberrations in cell cycle pathways, including amplification of cyclin D1. Palbociclib (PAL), a cyclin-dependent kinase 4/6 (CDK4/6) inhibitor, has been reported to regulate cell cycle progression in HNC. However, recent studies have revealed the acquired resistance of certain cells to PAL through activation of the mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway. Therefore, we investigated whether the inhibition of MEK/ERK pathway by trametinib (TRA) may overcome the limited efficacy of PAL in HNC. We evaluated the effect of PAL alone and in combination with TRA on the viability of HNC cells, and found that the combination treatment synergistically inhibited the proliferation of HNC cells. The combination treatment induced G0/G1 cell cycle arrest and apoptotic cell death. In particular, apoptosis mediated by the combination treatment was accompanied with an increase in caspase-3 activity and the number of TUNEL-positive apoptotic cells. These results were consistent with the decrease in cell cycle progression and mitogen-activated protein kinase (MAPK) pathway activation. In a xenograft mouse model of HNC, PAL and TRA synergistically inhibited tumor growth and enhanced tumor cell apoptosis, consistent with the increase in the number of TUNEL-positive cells. The anti-proliferative effects were evident in tumor tissues subjected to the combination treatment as compared with those treated with single drug. Taken together, our study demonstrates that the combination of PAL and TRA exerts synergistic anticancer effects and inhibits cell cycle check points and MEK/ERK pathway in HNC, suggestive of their potential application for HNC treatment.

Engineered algae: A novel oxygen-generating system for effective treatment of hypoxic cancer.

Microalgae, a naturally present unicellular microorganism, can undergo light photosynthesis and have been used in biofuels, nutrition, etc. Here, we report that engineered live microalgae can be delivered to hypoxic tumor regions to increase local oxygen levels and resensitize resistant cancer cells to both radio- and phototherapies. We demonstrate that the hypoxic environment in tumors is markedly improved by in situ-generated oxygen through microalgae-mediated photosynthesis, resulting in notably radiotherapeutic efficacy. Furthermore, the chlorophyll from microalgae produces reactive oxygen species during laser irradiation, further augmenting the photosensitizing effect and enhancing tumor cell apoptosis. Thus, the sequential combination of oxygen-generating algae system with radio- and phototherapies has the potential to create an innovative treatment strategy to improve the outcome of cancer management. Together, our findings demonstrate a novel approach that leverages the products of photosynthesis for treatment of tumors and provide proof-of-concept evidence for future development of algae-enhanced radio- and photodynamic therapy.