Synergistic Anticancer Effect Research Articles

HDAC8-Selective Inhibition by PCI-34051 Enhances the Anticancer Effects of ACY-241 in Ovarian Cancer Cells.

HDAC6 is overexpressed in ovarian cancer and is known to be correlated with tumorigenesis. Accordingly, ACY-241, a selective HDAC6 inhibitor, is currently under clinical trial and has been tested in combination with various drugs. HDAC8, another member of the HDAC family, has recently gained attention as a novel target for cancer therapy. Here, we evaluated the synergistic anticancer effects of PCI-34051 and ACY-241 in ovarian cancer. Among various ovarian cancer cells, PCI-34051 effectively suppresses cell proliferation in wild-type p53 ovarian cancer cells compared with mutant p53 ovarian cancer cells. In ovarian cancer cells harboring wild-type p53, PCI-34051 in combination with ACY-241 synergistically represses cell proliferation, enhances apoptosis, and suppresses cell migration. The expression of pro-apoptotic proteins is synergistically upregulated, whereas the expressions of anti-apoptotic proteins and metastasis-associated proteins are significantly downregulated in combination treatment. Furthermore, the level of acetyl-p53 at K381 is synergistically upregulated upon combination treatment. Overall, co-inhibition of HDAC6 and HDAC8 through selective inhibitors synergistically suppresses cancer cell proliferation and metastasis in p53 wild-type ovarian cancer cells. These results suggest a novel approach to treating ovarian cancer patients and the therapeutic potential in developing HDAC6/8 dual inhibitors.

The Efficacy and Mechanism of Proteasome Inhibitors in Solid Tumor Treatment.

The ubiquitin-proteasome system (UPS) is critical in cellular protein degradation and widely involved in the regulations of cancer hallmarks. Targeting the UPS pathway has emerged as a promising novel treatment in hematological malignancies and solid tumors. This review mainly focuses on the preclinical results of proteasome inhibitors in solid tumors. We analyzed the published articles associated with the anticancer results of proteasome inhibitors alone or combination chemotherapy in solid tumors. Important data presented in abstract form were also discussed in this review. Proteasome inhibitors, such as bortezomib and carfilzomib, are highly effective in treating solid tumors. The anticancer efficacy is not limited to affect the proteasomal inhibition- associated signaling pathways but also widely involves the signaling pathways related to cell cycle, apoptosis, and epithelial-mesenchymal transition (EMT). In addition, proteasome inhibitors overcome the conventional chemo-resistance of standard chemotherapeutics by inhibiting signaling pathways, such as NF-κB or PI3K/Akt. Combination chemotherapy of proteasome inhibitors and standard chemotherapeutics are widely investigated in multiple relapsed or chemo-resistant solid tumor types, such as breast cancer and pancreatic cancer. The proteasome inhibitors re-sensitize the standard chemotherapeutic regimens and induce synergistic anticancer effects. The development of novel proteasome inhibitors and delivery systems also improves the proteasome inhibitors' anticancer efficacy in solid tumors. This review summarizes the current preclinical results of proteasome inhibitors in solid tumors and reveals the potential anticancer mechanisms.

Computational Exploration of the Synergistic Anticancer Effect of a Multi-Action Ru(II)-Pt(IV) Conjugate.

An in-depth computational study of the ability of a recently proposed multi-action Ru(II)–Pt(IV) conjugate to act as a photosensitizer in photodynamic therapy (PDT) and chemotherapeutic drugs is presented here. The investigated complex is characterized by a polypyridyl Ru(II) chromophore linked to a Pt(IV) complex that, acting as a prodrug, should be activated by reduction releasing the Ru-based chromophore that can absorb light of proper wavelength to be used in PDT. The reaction mechanism for active species formation has been fully elucidated by means of density functional theory and its time-dependent extension. The reduction mechanism, assisted by ascorbate, of the Pt(IV) prodrug to the Pt(II) active species has been explored, taking into consideration all the possible modes of attack of the reductant for releasing the axial ligands and affording active cisplatin. Given the similarity in the photophysical properties of the chromophore linked or not to the Pt(IV) complex, both the Ru(II)–Pt(IV) conjugate precursor and the Ru(II) chromophore should be able to act as PDT photosensitizers according to type I and type II photoprocesses. In particular, they are able to generate singlet oxygen cytotoxic species as well as auto-ionize to form highly reactive O2–• species.

Matairesinol Induces Mitochondrial Dysfunction and Exerts Synergistic Anticancer Effects with 5-Fluorouracil in Pancreatic Cancer Cells.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive types of cancer and exhibits a devastating 5-year survival rate. The most recent procedure for the treatment of PDAC is a combination of several conventional chemotherapeutic agents, termed FOLFIRINOX, that includes irinotecan, leucovorin, oxaliplatin, and 5-fluorouracil (5-FU). However, ongoing treatment using these agents is challenging due to their severe side effects and limitations on the range of patients available for PDAC. Therefore, safer and more innovative anticancer agents must be developed. The anticarcinoma activity of matairesinol that can be extracted from seagrass has been reported in various types of cancer, including prostate, breast, cervical, and pancreatic cancer. However, the molecular mechanism of effective anticancer activity of matairesinol against pancreatic cancer remains unclear. In the present study, we confirmed the inhibition of cell proliferation and progression induced by matairesinol in representative human pancreatic cancer cell lines (MIA PaCa-2 and PANC-1). Additionally, matairesinol triggers apoptosis and causes mitochondrial impairment as evidenced by the depolarization of the mitochondrial membrane, disruption of calcium, and suppression of cell migration and related intracellular signaling pathways. Finally, matairesinol exerts a synergistic effect with 5-FU, a standard anticancer agent for PDAC. These results demonstrate the therapeutic potential of matairesinol in the treatment of PDAC.

Targeted co-delivery of doxorubicin and methotrexate to breast cancer cells by a pH-sensitive biocompatible polymeric system based on β-cyclodextrin crosslinked glycodendrimer with magnetic ZnO core

Nowadays, co-delivery of multiple therapeutics and combinational therapies using a delivery system is a promising approach to attain a synergistic anticancer effect. Hence, in the present study, we designed and synthesized a new pH-sensitive and biocompatible glycodendrimer immobilized on ZnO coated magnetic nanocomposite (Fe3O4@ZnO@CAMAD-β-CD) with antioxidant properties for co-delivery of doxorubicin (DOX) and methotrexate (MTX) to breast cancer cells. The structural properties of the new synthesized system were analyzed using various techniques. The drug loading results revealed that the Fe3O4@ZnO@CAMAD-β-CD nanocomposite displayed encapsulation efficiency (EE) of 96.08 % for DOX and 68.03 % for MTX. In vitro drug release study at pHs 5, 6.8, and 7.4 also showed that the release process was noticeably controlled, and pH-dependent manner with tumor target release behavior. Furthermore, the results of MTT cytotoxicity assessment, DAPI staining, confocal microscopy, and flow cytometry analysis against MDA-MB-231 breast cancer cell lines illustrated that the prepared Fe3O4@ZnO@CAMAD-β-CD has good biocompatibility and could easily enter the cells. The flow-cytometry analysis also showed that the apoptotic effects of DOX-MTX- Fe3O4@ZnO@CAMAD-β-CD have higher due to the synergistic effect in comparison to free drugs. The DPPH test for the study of antioxidant activity of Fe3O4@ZnO@CAMAD-β-CD nanocomposite showed that the carrier has excellent antioxidant activity (81.3 %). According to the results of this study, the prepared Fe3O4@ZnO@CAMAD-β-CD as a biocompatible carrier could be successfully used in the targeted co-delivery of DOX and MTX to cancer cells.

One-Pot Synthesis of Ag/Quaternary Ammonium Salt Co-Decorated Mesoporous Silica Nanoparticles for Synergistic Treatment of Cancer and Bacterial Infections.

Developing drug delivery nanosystems with both anticancer and antibacterial effects is of great clinical value. Herein, we report a facile approach to synthesize Ag and quaternary ammonium salt (QAS) co-decorated mesoporous silica nanoparticles (MSNs), namely, Ag/QAS-MSNs, for synergistic treatment of cancer and bacterial infections. In vitro studies demonstrated that Ag/QAS-MSNs not only had a strong antibacterial activity against the bacterial pathogens but also could efficiently induce cancer cell death through an apoptotic pathway. Moreover, in vivo combination therapy with Ag and QAS in Ag/QAS-MSNs was also tested in a nude mouse tumor model, and a significant synergistic anticancer effect, which is superior to that obtained by therapy with Ag-MSNs or QAS-MSNs alone, was achieved. Such excellent anticancer and antibacterial activity of Ag/QAS-MSNs could be attributed to the synergistic effect of Ag ions and QAS. Thus, Ag/QAS-MSNs have a promising future as potent anticancer agents with high antibacterial performance.

Solid Self-Nano Emulsifying Nanoplatform Loaded with Tamoxifen and Resveratrol for Treatment of Breast Cancer.

The solid self-nanoemulsifying drug delivery system (s-SNEDDS) is a growing platform for the delivery of drugs via oral route. In the present work, tamoxifen (TAM) was loaded in SNEDDS with resveratrol (RES), which is a potent chemotherapeutic, antioxidant, anti-inflammatory and P-gp inhibitor for enhancing bioavailability and to obtain synergistic anti-cancer effect against breast cancer. SNEDDS were developed using capmul MCM as oil, Tween 80 as surfactant and transcutol-HP as co-surfactant and optimized by central composite rotatable design. Neusilin US2 concentration was optimized for adsorption of liquid SNEDDS to prepare s-SNEDDS. The developed formulation was characterized and investigated for various in vitro and cell line comparative studies. Optimized TAM-RES-s-SNEDDS showed spherical droplets of a size less than 200 nm. In all in vitro studies, TAM-RES-s-SNEDDS showed significantly improved (p ˂ 0.05) release and permeation across the dialysis membrane and intestinal lumen. Moreover, TAM-RES-s-SNEDDS possessed significantly greater therapeutic efficacy (p < 0.05) and better internalization on the MCF-7 cell line as compared to the conventional formulation. Additionally, oral bioavailability of TAM from SNEDDS was 1.63 folds significantly higher (p < 0.05) than that of combination suspension and 4.16 folds significantly higher (p < 0.05) than TAM suspension. Thus, findings suggest that TAM- RES-s-SNEDDS can be the future delivery system that potentially delivers both drugs to cancer cells for better treatment.

Co-Delivery of erlotinib and resveratrol via nanostructured lipid Carriers: A synergistically promising approach for cell proliferation prevention and ROS-Mediated apoptosis activation

Cancer treatments are always associated with various challenges, and scientists are constantly trying to find new therapies and methods. Erlotinib (ELT) is a well-known medicine against non-small cell lung cancer (NSCLC). However, treatments by ELT disrupt therapy due to drug resistance and pose severe challenges to patients. To achieve high-performance treatment, we gained nanostructured lipid carriers (NLCs) to evaluate synergistic anticancer effects of co-delivery of ELT and resveratrol (RES), a natural herbal derived phenol against NSCLC. NLCs are prepared via the hot homogenization method and characterized. In vitro cytotoxicity of formulations were evaluated on adenocarcinoma human alveolar basal epithelial (A549) cells. Prepared NLCs showed a narrow particle size (97.52 ± 17.14 nm), negative zeta potential (-7.67 ± 4.55 mV), and high encapsulation efficiency (EE%) was measured for the prepared co-delivery system (EE% 89.5 ± 5.16 % for ELT and 90.1 ± 6.61 % for RES). In vitro outcomes from cell viability study (12.63 % after 48 h of treatment), apoptosis assay (85.50%.), cell cycle (40.00% arrest in G2-M), and western blotting investigations (decreasing of protein expression levels of survivin, Bcl-2, P-Caspase 3P-caspase 9, and P-ERK 1/2, and additionally, increasing protein levels of BAX, P53, C-Caspase 3 and 9), DAPI staining, and colony formation assays showed the augment cytotoxic performances for co-delivery of ELT and RES loaded NLCs. Our study introduced the co-delivery of ELT and RES by NLCs as a novel strategy to elevate the efficacy of chemotherapeutics for NSCLC.

Pentagalloyl Glucose and Cisplatin Combination Treatment Exhibits a Synergistic Anticancer Effect in 2D and 3D Models of Head and Neck Carcinoma.

Although cisplatin is a first-line chemotherapy drug for head and neck squamous cell carcinoma (HNSCC), its therapeutic efficacy is limited owing to serious side effects and acquired drug resistance. This study determined whether combining pentagalloyl glucose (PGG) and cisplatin enhanced their anti-tumor activities on HNSCC cell lines. We investigated the anticancer effect of PGG combined with cisplatin in 2D and 3D multicellular spheroid cell culture. The results revealed that PGG combined with cisplatin inhibited cell viability and produced synergistic effects. PGG potentiates the anticancer effect of cisplatin by promoting apoptosis and inhibiting cell migration. The western blot and molecular docking analysis revealed that the synergistic effect of the combination treatment may be related to the PGG-mediated reduced expression of phosphorylated STAT3 and phosphorylated Akt. Furthermore, we found that the combined treatment of PGG and cisplatin’s effect on 3D multicellular spheroid size was more potent than the monotherapies. Our findings indicated that the combination therapy of PGG and cisplatin synergistically inhibited HNSCC cancer cell viability and induced apoptosis in 2D and 3D models. The present results suggested that PGG may be a promising adjunct drug used with cisplatin for a practical therapeutic approach to head and neck cancer.

Molecular dynamics simulation and in vitro evaluation of herb-drug interactions involving dietary polyphenols and CDK inhibitors in breast cancer chemotherapy.

Dietary polyphenols such as quercetin and curcumin have been extensively administered to patients with cancer in the form of herbal supplements. They may have a synergistic anticancer effect; however, a risk of pharmacokinetic interactions with selective CDK-4/6 inhibitors that are metabolized by the CYP3A4 enzyme exists. Considering these pharmacokinetic aspects, the current study examined the effects of curcumin and quercetin on human CYP3A4 to ascertain CYP3A4-mediated herb-drug interactions with CDK inhibitors. In this study, using in silico methods and CYP3A4 inhibition kinetics in human liver microsomes and recombinant CYP3A4 enzymes, the effects of concentration-dependent inhibition of CYP3A4 by quercetin and curcumin on CDK inhibitors metabolism were examined. Based on our in-silico docking findings, curcumin and quercetin were considerably bound to CYP3A4 protein and displace CDK inhibitors from the CYP3A4 substrate binding domain. The IC50 values of curcumin and quercetin were 16.10 and 0.05 μM, respectively, for CYP3A4-mediated 1'-hydroxylation of midazolam. The dietary polyphenols prolonged the in vitro half-life of palbociclib and ribociclib by 6.4-fold and decreased their intrinsic microsomal clearance by approximately 4.6 times. Our findings indicate that curcumin and quercetin effectively cause herb-drug interactions and should be cautiously used to avoid therapeutic failure.

Visualizing Lysosomal Positioning with a Fluorescent Probe Reveals a New Synergistic Anticancer Effect

The observation and discovery of lysosome dynamic alterations will greatly contribute to the in-depth understanding of lysosome biology and the development of new cancer therapeutics. To visualize lysosomal dynamics, here we have developed a lysosome-targetable fluorescent probe of NIM-3 showing integrated high selectivity, high photostability, and low cytotoxicity. With the aid of the excellent spatial and temporal imaging capability of NIM-3, three different types of motion of lysosomes were defined, and perinuclear accumulation of lysosomes in response to the pro-inflammatory cytokine stimulus was observed in various cells. More importantly, through lysosomal positioning studies, a new and potential anticancer therapy, i.e., the combination treatment of TNFα (tumor necrosis factor alpha) and chloroquine (CQ, a lysosomal pH elevator), was disclosed. The efficacy of the "CQ + TNFα" treatment was verified by different types of human cancer cells, and the anticancer mechanism may be partially attributed to lysosomal dilation.

Co-Delivery of Repurposing Itraconazole and VEGF siRNA by Composite Nanoparticulate System for Collaborative Anti-Angiogenesis and Anti-Tumor Efficacy against Breast Cancer

Combinations of two different therapeutic modalities of VEGF inhibitors against angiogenesis can cooperatively impede breast cancer tumor growth and enhance therapeutic efficacy. Itraconazole (ITZ) is a conventional antifungal drug with high safety; however, it has been repurposed to be a multi target anti-angiogenesis agent for cancer therapy in recent years. In the present study, composite nanoparticles co-loaded with ITZ and VEGF siRNA were prepared in order to investigate their anti-angiogenesis efficacy and synergistic anticancer effect against breast cancer. The nanoparticles had a suitable particle size (117.9 ± 10.3 nm) and weak positive surface charge (6.69 ± 2.46 mV), as well as good stability and drug release profile in vitro. Moreover, the nanoparticles successfully escaped from endosomes and realized cell apoptosis and cell proliferation inhibition in vitro. In vitro and in vivo experiments showed that the nanoparticles could induce the silencing of VEGF-related expressions as well as anti-angiogenesis efficacy, and the co-loaded ITZ-VEGF siRNA NPs could inhibit tumor growth effectively with low toxicity and side effects. Taken together, the as-prepared delivery vehicles are a simple and safe nano-platform that improves the antitumor efficacy of VEGF siRNA and ITZ, which allows the repositioning of the generic drug ITZ as a great candidate for antitumor therapy.

Chemo-Phototherapy with Carfilzomib-Encapsulated TiN Nanoshells Suppressing Tumor Growth and Lymphatic Metastasis.

The design of nanomedicine for cancer therapy, especially the treatment of tumor metastasis has received great attention. Proteasome inhibition is accepted as a new strategy for cancer therapy. Despite being a big breakthrough in multiple myeloma therapy, carfilzomib (CFZ), a second-in-class proteasome inhibitor is still unsatisfactory for solid tumor and metastasis therapy. In this study, hollow titanium nitride (TiN) nanoshells are synthesized as a drug carrier of CFZ. The TiN nanoshells have a high loading capacity of CFZ, and their intrinsic inhibitory effect on autophagy synergistically enhances the activity of CFZ. Due to an excellent photothermal conversion efficiency in the second near-infrared (NIR-II) region, TiN nanoshell-based photothermal therapy further induces a synergistic anticancer effect. In vivo study demonstrates that TiN nanoshells readily drain into the lymph nodes, which are responsible for tumor lymphatic metastasis. The CFZ-loaded TiN nanoshell-based chemo-photothermal therapy combined with surgery offers a remarkable therapeutic outcome in greatly inhibiting further metastatic spread of cancer cells. These findings suggest that TiN nanoshells act as an efficient carrier of CFZ for realizing enhanced outcomes for proteasome inhibitor-based cancer therapy, and this work also presents a "combined chemo-phototherapy assisted surgery" strategy, promising for future cancer treatment.

Abstract 1047: Combinatorial anticancer therapy strategy using a pan-class I glucose transporter inhibitor with chemotherapy and target drugs in vitro and in vivo

Abstract Non-Small Cell Lung Cancer (NSCLC) is the most common type of lung cancer, accounting for 84% of all lung cancer diagnoses. While there are current standard treatments for NSCLC, these treatments may cause severe side effects, drug resistance, or lead to ineffective treatment, recurrence of the cancer, and death. It has been shown that most cancer types are “addicted” to glucose, and are sensitive and vulnerable to glucose deprivation, making the inhibition of glucose transport into these cells an attractive anticancer strategy. DRB18 is a small molecule proprietary compound that has been shown to target and inhibit class I glucose transporters (GLUTs, GLUT1-4), which are responsible for the uptake of glucose into cells, particularly these types of cancer cells. DRB18 has been shown to be effective in inhibiting cancer cell growth in vitro and in vivo without noticeable side effects.1 While this may be a promising anticancer therapy by itself, combining DRB18 with another anticancer drug that has a totally different anticancer mechanism should substantially increase the efficacy of the treatment while potentially minimizing the rate of resistance and recurrence of the cancer without increasing unwanted side effects. This research focuses on combining DRB18 with FDA-approved target drugs Trametinib and Brigatinib, the FDA-approved chemotherapy drug Paclitaxel, and a glutamine transporter inhibitor (V-9302). Thus, the treatment groups are vehicle, each of the previously mentioned drugs alone, as well as DRB18+Trametinib, DRB18+Brigatinib, DRB18+Paclitaxel, and DRB18+V-9302. This study tests the hypothesis that, due to their different anticancer mechanisms, the combination of DRB18 with these anticancer drugs will have a synergistic anticancer effect. Preliminary in vitro data and an in vivo pilot tumor study in nude mice, using human NSCLC A549 cells, have shown the improved anticancer efficacy of the combinatorial approach by further reducing tumor growth when compared with single drug treatment. The results of a larger nude mouse study, as well as basic mechanistic studies in vitro, that are currently underway will be presented later at the AACR meeting. This combination therapy has great therapeutic implications and the potential to benefit cancer patients for decades to come. 1. Shriwas P, Roberts D, Li Y, Wang L, Qian Y, Bergmeier S, Hines J, Adhicary S, Nielsen C, &amp; Chen X. (2021). A small molecule pan-class I glucose transporter inhibitor reduces cancer cell proliferation in vitro and tumor growth in vivo by targeting glucose-based metabolism. Cancer and Metabolism, 9 (14). Citation Format: Lindsey M. Bachmann, Pratik Shriwas, Ryan A. Ward, Liyi Wang, Stephen C. Bergmeier, Yunsheng Li, Xiaozhuo Chen. Combinatorial anticancer therapy strategy using a pan-class I glucose transporter inhibitor with chemotherapy and target drugs in vitro and in vivo [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 1047.

Abstract 3026: Inhibition of glutaminolysis overcomes metabolic adaptation to devimistat treatment

Abstract The identification and development of reagents that can limit preferential metabolic effectors in tumors as well as trigger unfavorable tumoral metabolic cues is of tremendous importance for suppressing malignancy. However, insufficient blocking of critical metabolic dependencies of cancer allows the development of metabolic bypasses, which significantly dampens therapeutic benefits of selective agents that target a single metabolic enzyme or pathway. We report here that head and neck squamous cell carcinoma (HNSCC) cells display strong addiction to glutamine. Devimistat, a novel lipoate analog, redirects cellular activity towards tumor-promoting glutaminolysis, leading to low anticancer efficacy in HNSCC cells. Mechanistically, devimistatinhibits the tricarboxylic acid cycle by blocking the enzyme activities of pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase, which upregulates GLS1 and eventually promotes the compensatory role of glutaminolysis in cancer cell survival. Most importantly, the addition of a GLS1 inhibitor CB-839 to devimistat treatment abrogates the metabolic dependency of HNSCC cells on glutamine, achieving a synergistic anticancer effect in glutamine-addicted HNSCC. These novel and significant findings could lay a scientific foundation for developing more effective treatments targeting the metabolic requirements of HNSCC. Citation Format: Liwei Lang, Fang Wang, Chloe Shay, Yonggang Ke, Nabil Saba, Yong Teng. Inhibition of glutaminolysis overcomes metabolic adaptation to devimistat treatment [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 3026.

Abstract 6022: Synergistic anti-cancer effects of selinexor and bevacizumab in mouse xenograft models of glioblastoma

Abstract Background: Glioblastoma (GBM) is the most common primary brain tumor with a poor prognosis. It is also one of the most vascularized human tumors. The anti-angiogenesis agent bevacizumab (BEV) is the only US FDA approved agent for recurrent GBM. Given the high resistance of GBM to current therapies and the failure of BEV to prolong overall survival, new therapeutic agents are in urgent need. Selinexor is a first-in-class oral inhibitor of nuclear export protein Exportin 1 (XPO1/CRM1), it readily crosses the blood-brain-barrier and demonstrates anti-cancer activity in various hematological and solid tumors. Selinexor can attenuate multiple cancer hallmarks simultaneously, anti-angiogenesis is one of the many anti-cancer mechanisms that selinexor has. In a phase 2 clinical trial of recurrent GBM, selinexor monotherapy demonstrated clinically relevant disease control with manageable side effects (Lassman 2021 Clin Cancer Res). We tested mouse xenograft models of GBM to evaluate the anti-GBM effects of selinexor and BEV. Methods: Thirty-two female nude mice with subcutaneously implanted U87MG xenografts were allocated to four treatment groups of eight mice: vehicle control, selinexor, BEV, and the selinexor and BEV combination. Selinexor was given via oral gavage at 15 mg/kg once a week on Mondays, and BEV was given at 2.5 mg/kg via intraperitoneal injection every three days, starting on Monday, for four weeks. Tumor volume and body weight of test mice were monitored throughout the experiment. Xenograft tumor samples were collected at the end of the study for gene expression analysis and immunohistochemistry tests. Results: Selinexor and BEV significantly inhibited tumor growth as single agents relative to controls, at Day 26, tumor growth inhibition (TGI) of 54.1% (p&amp;lt;0.0001) and 64.0% (p&amp;lt;0.0001), respectively. The combination of the two agents almost completely inhibited tumor growth, with a TGI of 95% (p&amp;lt;0.0001). Gene expression analysis showed that genes involved in angiogenesis were significantly downregulated in tumor samples collected from mice treated with both agents and was more significant than in animals treated with BEV alone. Conclusions: Synergistic anti-GBM effects of selinexor and BEV are likely due to the enhanced inhibition of angiogenesis related genes. An ongoing GBM clinical trial (XPORT-GBM-029, NCT04421378) is investigating the therapeutic efficacy of selinexor and BEV combination. Citation Format: Leah Henegar, Hua Chang, Christopher J. Walker, Trinayan Kashyap, Marie Maloof, Feng Wang, Kathleen Martyn, Shira Orr, Sharon Tamir, Michael G. Kauffman, Sharon Shacham, Yosef Landesman. Synergistic anti-cancer effects of selinexor and bevacizumab in mouse xenograft models of glioblastoma [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 6022.

Abstract 6023: Selinexor synergizes with temozolomide in preclinical models of glioblastoma independent of MGMT promoter methylation

Abstract Background: The alkylating agent temozolomide (TMZ) is widely applied as an effective first line treatment to glioblastoma (GBM), but its effectiveness is substantially reduced by the MGMT O6-methylguanine-DNA methyltransferase that repairs the main cytotoxic methylguanine generated by TMZ. Thus, TMZ is more effective in patients who have GBM with MGMT gene silencing promoter hypermethylation. Selinexor is an oral selective inhibitor of Exportin-1 (XPO1/CRM1) with efficacy in various solid and hematological cancers and clinically approved to treat multiple myeloma and diffuse large B cell lymphoma. Selinexor also crosses the blood brain barrier and demonstrates clinically relevant disease control with manageable and reversible side effects in a phase 2 clinical trial for patients with recurrent GBM as a monotherapy (Lassman 2021 Clin Cancer Res). To evaluate the effects of selinexor and TMZ combination, preclinical studies were performed with GBM cell lines in vitro and in mouse xenograft models in vivo. Methods: Cytotoxic effects of selinexor and TMZ were evaluated with two GBM cell lines LN18 and U87MG. The MGMT promoter is hypermethylated in U87MG cells while unmethylated in LN18 cells. The anti-cancer effects of selinexor (20 mg/kg, PO, once weekly) and TMZ (50 mg/kg, PO, QDX5, week 1 only) were also tested in a mouse xenograft model of U87MG using different dosing schedules (8 mice per treatment group). Results: Synergistic cytotoxic effects of selinexor and TMZ were observed in vitro in both LN18 and U87MG cells, regardless of the methylation status of MGMT promoter. In mouse xenograft models of U87MG, at Day 29 of study, compared with the control group, tumor growth inhibition (TGI) is 64.5% (p=0.0002) for selinexor and 67.2% (p=0.0001) for TMZ. The combination of the two agents completely inhibited tumor growth, with a TGI of 101.9% (p&amp;lt;0.0001) for a concomitant schedule and a TGI of 104.1% (p&amp;lt;0.0001) for a sequential schedule. Conclusion: The selinexor and TMZ combination demonstrated synergistic anti-cancer effects in preclinical GBM models. Previous studies have shown that selinexor treatment reduces DNA damage repair proteins involved in multiple DNA repair pathways, which would provide a mechanism to enhance the cytotoxic effects of TMZ in GBM cells independent of MGMT promoter methylation. This combination is now being investigated in an ongoing GBM clinical trial (XPORT-GBM-029, NCT04421378). Citation Format: Leah Henegar, Hua Chang, Christopher J. Walker, Trinayan Kashyap, Marie Maloof, Feng Wang, Kathleen Martyn, Shira Orr, Sharon Tamir, Michael G. Kauffman, Sharon Shacham, Yosef Landesman. Selinexor synergizes with temozolomide in preclinical models of glioblastoma independent of MGMT promoter methylation [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 6023.

Abstract 1286: Oral administration of poly gamma glutamic acid significantly enhances the antitumor immune response of doxorubicin in a murine cancer model through regulating tumor microenvironment

Abstract Immunogenic cell death (ICD) is a type of cancer cell death triggered by certain chemotherapeutic drugs, oncolytic viruses, and other therapies. In particular, doxorubicin (DOX), one of the chemo-drugs, is well known to induce ICD, which involves the activation of the immune system against cancer in immunocompetent hosts. ICD comprises the release of damage-associated molecular patterns (DAMPs) from dying tumor cells that result in the activation of tumor-specific immune responses, thus eliciting long-term efficacy of anticancer drugs by combining direct cancer cell killing and antitumor immunity. However, the antitumor immunity can be achieved by overcoming the immunosuppressive tumor microenvironment (TME). Most current treatment strategies harnessing the tumor microenvironment focus on T cell-immune response, either by promoting activating signals or suppressing inhibitory ones.We here present a novel approach to cope with the inhibitory TME, combinatory treatment of DOX with poly gamma glutamic acid (γ-PGA). PGA, a safe edible biomaterial secreted by B. subtillis, has been evaluated in the clinical trials with the patients diagnosed as cervical intraepithelial neoplasia 1 (CIN 1). From the study using murine cancer models, including MC38, we found the combinatory treatment with γ-PGA restored the downregulation of NK cell activity caused by DOX, enhanced ICD and T cell responses, and reduced proinflammatory cytokines in the tumor tissues. Taken together, co-administration of γ-PGA exhibited synergistic anti-cancer effects by favoring the immunosuppressive TME in the combinatory treatment with conventional chemo-drugs. Citation Format: Joungwoo Choi, Solmin Jung, Yena Oh, Jaepyeong Jang, Yeondong Cho, Do young Lee, Youngcheol Park, Kwangil Jeong. Oral administration of poly gamma glutamic acid significantly enhances the antitumor immune response of doxorubicin in a murine cancer model through regulating tumor microenvironment [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 1286.

Abstract 1800: Novel NSDHL inhibitor (Compound 9) exerts anti-proliferative and cytotoxic activity in breast cancer cells

Abstract Background: NAD(P) Dependent Steroid Dehydrogenase-Like (NSDHL) is an enzyme involved in post-squalene cholesterol biosynthesis. We recently suggest new insights into the critical role of the NSDHL involved in breast tumor growth and metastasis and its potential for targeted cancer therapy. Compound 9, which is a novel inhibitor of NSDHL, was kindly provided by Dr. Lee B-J in Seoul National University College of Pharmacy. This study aimed to investigate the anti-cancer potential of Compound 9 in breast cancer. Methods: Therapeutic potential of Compound 9 (10~100 μM) was investigated in several human breast cancer cell lines. Total intracellular cholesterol level was measured using Total Cholesterol Assay Kit. Cell cycle analysis using DNA staining with PI, apoptosis analysis using Annexin V/PI-labeling, and transwell migration assay were performed. The Synergistic anticancer effect of compound-9 and paclitaxel was evaluated by crystal violet assay. Western blot and immunofluorescent staining were assessed for investigating the mechanism by which Compound 9 exerts the anti-cancer effect. Results: Time-dependent intracellular uptake of Compound 9 by breast cancer cells was observed. Compound 9 induced cytotoxic, anti-proliferative, and apoptotic effects and cell cycle arrest (G0/G1), and suppressed migration activity on diverse breast cancer cell lines in a time- and dose-dependent manner. Total intracellular cholesterol level was reduced by Compound 9. Combination with Compound-9 and Paclitaxel led to synergistic cytotoxicity. Compound-9 increased the autophagy-related proteins (P62, LC3II) but decreased the anti-apoptotic proteins (XIAP, BCL2). Conclusion: Our data show that Compound 9 exerts strong anti-proliferative and cytotoxic activity in breast cancer cells, suggesting potential additional utility as an anti-cancer drug. Further studies are necessary to validate the potential anti-cancer effect of Compound-9 in breast tumor mice models. Citation Format: So-Hyun Yoon, Hoe Suk Kim, Moonjou Baek, Seungyeon Ryu, Sangeun Lee, Han-Byoel Lee, Bong-Jin Lee, Wonshik Han. Novel NSDHL inhibitor (Compound 9) exerts anti-proliferative and cytotoxic activity in breast cancer cells [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 1800.

Synergistic co-administration of docetaxel and curcumin to chemoresistant cancer cells using PEGylated and RIPL peptide-conjugated nanostructured lipid carriers

BackgroundA targeted co-administration system of docetaxel (DTX) and curcumin (CUR) using a PEG-modified RIPL peptide (IPLVVPLRRRRRRRRC)-conjugated nanostructured lipid carrier (P/R-NLC) was constructed to exert synergistic anticancer effects against chemoresistant breast cancer.ResultsDTX- or CUR-loaded NLCs and P/R-NLCs were prepared using the solvent emulsification–evaporation method. NLCs showed homogeneous spherical morphology with nano-sized dispersion (< 210 nm) with zeta potential varying from − 16.4 to − 19.9 mV. DTX or CUR was successfully encapsulated in the NLCs: encapsulation efficiency (> 95%); drug loading (8 − 18%). All NLC formulations were stable for 4 weeks under the storage conditions at 4 °C. Drug release was diffusion-controlled, revealing the best fit to the Higuchi equation. DTX- or CUR-loaded formulations showed dose-dependent cytotoxicity. The DTX/CUR combination (1:3 w/w) in P/R-NLC formulations exhibited the strongest synergism in both MCF7 and MCF7/ADR cells with combination index values of 0.286 and 0.130, respectively. Co-treatment with DTX- or CUR-P/R-NLCs increased apoptosis in both cell lines exhibited the superior synergistic inhibitory effect on MCF7/ADR three-dimensional spheroids. Finally, in OVCAR3-xenografted mouse models, co-treatment with DTX- or CUR-loaded P/R-NLCs significantly suppressed tumor growth compared to the other treatment groups.ConclusionsCo-administration of DTX/CUR (1:3 w/w) using P/R-NLCs induced a synergistic effect against chemoresistant cancer cells.Graphical