Resistant Models Research Articles

Observation of magnetic islands in tokamak plasmas during the suppression of edge-localized modes

AbstractIn tokamaks, a leading platform for fusion energy, periodic filamentary plasma eruptions known as edge-localized modes occur in plasmas with high-energy confinement and steep pressure profiles at the plasma edge. These edge-localized modes could damage the tokamak wall but can be suppressed using small three-dimensional magnetic perturbations. Here we demonstrate that these magnetic perturbations can change the magnetic topology just inside the steep gradient region of the plasma edge. We identify signatures of a magnetic island, and their observation is linked to the suppression of edge-localized modes. We compare high-resolution measurements of perturbed magnetic surfaces with predictions from ideal magnetohydrodynamic theory where the magnetic topology is preserved. Although ideal magnetohydrodynamics adequately describes the measurements in plasmas exhibiting edge-localized modes, it proves insufficient for plasmas where these modes are suppressed. Nonlinear resistive magnetohydrodynamic modelling supports this observation. Our study experimentally confirms the predicted role of magnetic islands in inhibiting the occurrence of edge-localized modes. This will be beneficial for physics-based predictions in future fusion devices to control these modes.

ETx-22: a novel nectin-4-directed antibody drug conjugate, demonstrates safety and potent antitumor activity in low nectin-4 expressing tumors.

Nectin-4 is a cell-adhesion molecule expressed at various levels in many solid tumors, including urothelial cancer. As means to reduce on-target skin toxicity observed with enfortumab vedotin, an anti-nectin-4-MMAE ADC approved for patients with advanced urothelial cancer, 15A7.5, an anti-nectin-4 monoclonal antibody that exhibited differential nectin-4 binding between tumor and primary keratinocytes, was selected for the development of ETx-22. Exatecan, a topoisomerase I inhibitor, was chosen as payload. ETx-22 ADC induced rapid and long-lasting tumor regression in various patient derived xenograft models expressing low to high levels of nectin-4 and also in MonoMethyl Auristatin-E resistant xenograft model. ETx-22 has a highest non severely toxic dose of over 20 mg/kg in non-human primates without signs of important skin toxicity. ETx-22 represents a valuable therapy, for the treatment of patients with nectin-4 expressing tumors including those that have become resistant to enfortumab vedotin treatment.

Abstract B053: Neoadjuvant Personalized Viral Vectored vaccines are highly effective against tumor relapse in checkpoint inhibitor resistant murine models

Abstract B053: Neoadjuvant Personalized Viral Vectored vaccines are highly effective against tumor relapse in checkpoint inhibitor resistant murine models

Berberine Ameliorates High-fat-induced Insulin Resistance in HepG2 Cells by Modulating PPARs Signaling Pathway.

Berberine (BBR), also known as berberine hydrochloride, was isolated from the rhizomes of the Coptis chinensis. Studies have reported that BBR plays an important role in glycolipid metabolism, including insulin (IR). The targets, and molecular mechanisms of BBR against hyperlipid-induced IR is worthy to be further studied. The related targets of BBR were identified via Pharmmapper database and relevant targets of diabetes were obtained through GeneCards and Online Mendelian Inheritance in Man (OMIM) database. The common targets were employed with the STRING database and visualized with the protein-protein interactions (PPI) network. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was performed to explore the biological progress and pathways. In vitro, human hepatocellular carcinomas (HepG2) cell was used as experimental cell line, and an insulin resistant HepG2 cell model (IR-HepG2) was constructed using free fatty acid induction. After intervention with BBR, glucose consumption and uptake in HepG2 cells were observed. Molecular docking was used to test the interaction between BBR and key targets, and real-time fluorescence quantitative PCR was used to detect the regulatory effect of BBR on related targets. 262 overlapped targets were extracted from BBR and diabetes. In the KEGG enrichment analysis, the peroxisome proliferator activated receptor (PPAR) signaling pathway was included. In vitro experiments, BBR can significantly increase sugar consumption and uptake in IR HepG2 cells, while PPAR inhibitors can weaken the effect of BBR on IR-HepG2. The PPAR signaling pathway is one of the important pathways for BBR to improve high-fat-induced insulin resistance in HepG2 cells.

Prediction of homologous recombination deficiency identifies colorectal tumors sensitive to PARP inhibition

The synthetic lethal effect observed with the use of PARP inhibitors (PARPi) with tumors characterized by the loss of key players in the homologous recombination (HR) pathway, commonly referred to as “BRCAness”, is maintaining high interest in oncology. While BRCAness is a well-established feature in breast, ovarian, prostate, and pancreatic carcinomas, our recent findings indicate that up to 15% of colorectal cancers (CRC) also harbor defects in the HR pathway, presenting promising opportunities for innovative therapeutic strategies in CRC patients. We developed a new tool called HRDirect, which builds upon the HRDetect algorithm and is able to predict HR deficiency (HRD) from reference-free tumor samples. We validated HRDirect using matched breast cancer and CRC patient samples. Subsequently, we assessed its efficacy in predicting response to the PARP inhibitor olaparib by comparing it with two other commercial assays: AmoyDx HRD by Amoy Diagnostics and the TruSight Oncology 500 HRD (TSO500-HRD) panel by Illumina NGS technology. While all three approaches successfully identified the most PARPi-sensitive CRC models, HRDirect demonstrated superior precision in distinguishing resistant models compared to AmoyDX and TSO500-HRD, which exhibited overlapping scores between sensitive and resistant cells. Furthermore, we propose integrating HRDirect scoring with ATM and RAD51C immunohistochemical analysis as part of our “composite biomarker approach” to enhance the identification of HRD tumors, with an immediate translational and clinical impact for CRC personalized treatment.

The SRC-family serves as a therapeutic target in triple negative breast cancer with acquired resistance to chemotherapy.

Resistance to chemotherapy, combined with heterogeneity among resistant tumors, represents a significant challenge in the clinical management of triple negative breast cancer (TNBC). By dissecting molecular pathways associated with treatment resistance, we sought to define patient sub-groups and actionable targets for next-line treatment. Bulk RNA sequencing and reverse phase protein array profiling were performed on isogenic patient-derived xenografts (PDX) representing paclitaxel-sensitive and -resistant tumors. Pathways identified as upregulated in the resistant model were further explored as targets in PDX explants. Their clinical relevance was assessed in two distinct patient cohorts (NeoAva and MET500). Increased activity in signaling pathways involving SRC-family kinases (SFKs)- and MAPK/ERK was found in treatment resistant PDX, with targeted inhibitors being significantly more potent in resistant tumors. Up-regulation of SFKs- and MAPK/ERK-pathways was also detected in a sub-group of chemoresistant patients after neoadjuvant treatment. Furthermore, High SFK expression (of either SRC, FYN and/or YES1) was detected in metastatic lesions of TNBC patients with fast progressing disease (median disease-free interval 27 vs 105 months). Upregulation of SFK-signaling is found in a subset of chemoresistant tumors and is persistent in metastatic lesions. Based on pre-clinical results, these patients may respond favorably to treatment targeting SFKs.

PI3Kδ activation, IL6 overexpression, and CD37 loss cause resistance to naratuximab emtansine in lymphomas

AbstractCD37-directed antibody and cellular-based approaches have shown preclinical and promising early clinical activity. Naratuximab emtansine (Debio 1562; IMGN529) is an antibody-drug conjugate (ADC) incorporating an anti-CD37 monoclonal antibody conjugated to the maytansinoid DM1 as payload, with activity as a single agent and in combination with rituximab in patients with lymphoma. We studied naratuximab emtansine and its free payload in 54 lymphoma models, correlated its activity with CD37 expression, characterized 2 resistance mechanisms, and identified combination partners providing synergy. The activity, primarily cytotoxic, was more potent in B- than T-cell lymphoma cell lines. After prolonged exposure to the ADC, 1 diffuse large B-cell lymphoma (DLBCL) cell line developed resistance to the ADC due to the CD37 gene biallelic loss. After CD37 loss, we also observed upregulation of interleukin-6 (IL6) and related transcripts. Recombinant IL6 led to resistance. Anti-IL6 antibody tocilizumab improved the ADC’s cytotoxic activity in CD37+ cells. In a second model, resistance was sustained by a PIK3CD activating mutation, with increased sensitivity to PI3Kδ inhibition and a functional dependence switch from MCL1 to BCL2. Adding idelalisib or venetoclax overcame resistance in the resistant derivative and improved cytotoxic activity in the parental cells. In conclusion, targeting B-cell lymphoma with the naratuximab emtansine showed vigorous antitumor activity as a single agent, which was also observed in models bearing genetic lesions associated with inferior outcomes, such as MYC translocations and TP53 inactivation or R-CHOP (rituximab, cyclophosphamide, doxorubicin, Oncovin [vincristine], and prednisone) resistance. Resistant DLBCL models identified active combinations of naratuximab emtansine with drugs targeting IL6, PI3Kδ, and BCL2.

Multiple enzyme-mimic polypeptide based carbon nanoparticles by ROP and Fe coordination for ROS regulation and photo-thermal therapy against bacterial infection

Novel strategy is urgently needed to overcome the bacterial infection all over the world due to unreasonable use of biotics. In recent years, nanozymes have attracted great interests of researchers for their high catalytic efficiency and biocompatibility. In this study, a novel multiple enzyme-mimic polypeptide-based carbon nanoparticle was synthesized by N-carboxyanhydride mediated ring opening polymerization (ROP) and Fe coordination for actualizing ROS regulation and photo-thermal therapy. The multiple enzyme-mimic activities of the nanozyme, such as peroxidase, oxidase, catalase, and glutathione peroxidase, were detailly explored in ROS regulation for potential utilization in bacterial inhibition. The photo-thermal effect of the nanozyme was investigated under 808 nm NIR irradiation. Enhanced inhibition rate of the as prepared nanozyme was observed against Gram-negative Escherichia coli (99.03 %) and Gram positive Staphylococcus aureus (99.78 %) planktonic bacteria. Methicillin-resistant Staphylococcus aureus (MRSA) was chosen as the drug resistant bacteria model to evaluate the efficiency in bacterial biofilm disruption. Improved healing efficacy of 99.05 % against MRSA wound infection and excellent biosafety were observed in mice model experiments for the as prepared nanozyme. In conclusion, the as synthesized nanozyme with ROS regulation, enhanced bacteria inhibition, and excellent biocompatibility could be potentially applied in clinic against bacterial infection.

Cultures derived from pancreatic cancer xenografts with long-term gemcitabine treatment produce chemoresistant secondary xenografts: Establishment of isogenic gemcitabine-sensitive and -resistant models

In attempts to establish sophisticated models to reproduce the process of acquired drug resistance, we transformed normal human pancreatic ductal epithelial cells by introducing genes for multiple cellular factors. We also created isogenic gemcitabine-sensitive and -resistant models by short- and long-term gemcitabine treatment, respectively. These models demonstrated differences in drug resistance in vivo, but not in vitro. Gemcitabine treatment also induced squamous transdifferentiation in xenografts in mice. The transcription factor p63 was identified as a possible resistance-determining factor but was unlikely to be solely responsible for the resistance to gemcitabine. This system would prove useful to discover novel molecular targets to overcome chemotherapy resistance, by allowing the evaluation of molecules of interest in xenograft models after in vitro genetic ablation.

12527 Determining The Impact Of Dampened Oxidative Stress On Islet Function And Gene Expression During Diabetes Onset In NOD Mice

Abstract Disclosure: K.V. Coutinho: None. H. Shinde: None. J. Feduska: None. K. Burnette: None. S.O. Poole: None. H.M. Tse: None. C.S. Hunter: None. Type 1 diabetes (T1D) arises from autoimmune destruction of insulin-producing pancreatic β-cells. Revealing the mechanisms underlying T1D onset are critical for therapeutic development but not completely understood. NADPH oxidase (NOX) generates superoxide, a precursor of reactive oxygen species (ROS), to regulate cell survival, differentiation, signaling, and autoimmune responses in T1D. NOD (Non-Obese Diabetic) mice spontaneously develop T1D, featuring increased cytokine/chemokine synthesis, inflammatory responsive macrophages and T cells, and ROS. Here, we harness NOD mice deficient in NOX-derived superoxide (NOD.Ncf1m[1]J), which have significantly lower T1D incidence. However, the impacts on islet β-cells in this T1D resistant model are unknown. We assessed a time course of glucose homeostasis between 6-20 weeks (W), spanning the onset T1D in NOD mice. Surprisingly, comparative glucose tolerance testing (GTT) in NOD.Ncf1m[1]J mice revealed increased glucose intolerance at 10W with no differences at 6, 14, and 20W as compared to NOD. Insulin tolerance was similar between the two models at all stages examined. This suggests superoxide production is necessary for β-cell function, despite that NOD.Ncf1m[1]J mice are T1D resistant. To understand islet transcriptomic changes between NOD and NOD.Ncf1m[1]J mice, we conducted comparative bulk islet RNA sequencing from 6 to 20W. Principal component analysis was applied to ensure differences between genotypes at each timepoint. Quality control methods within the Nextflow core pipeline were used to ensure sample quality. As expected, NOD.Ncf1m[1]J mice had decreased Ncf1 and immune response-related mRNA levels. Expression of T-cell exhaustion (Pdcd1, Lag3, and Tigit) genes remained level in NOD mice, but had significantly lower expression at 6W in NOD.Ncf1m[1]J mice. Interestingly, Ctla4, encoding a gene product that inhibits T-cell function, was upregulated at 14W in NOD.Ncf1m[1]J mice. Furthermore, GO analysis of downregulated NOD.Ncf1m[1]J gene sets include T-cell activation, response to IFN-β and IFN-γ at 6W, and decreased cytokine production at 20W. Supporting the dysregulation of β-cell function, Bace2, encoding a protease that limits β-cell function and mass, was upregulated with NOD. Ncf1m[1]J. Additionally, 14W β-cell function gene expression was decreased in the NOD.Ncf1m[1]J mice, including Slc2a2, which encodes the β-cell GLUT2 glucose transporter, and Glp1r, which is involved in preserving β-cell mass and function. Taken together, NOX-derived superoxide, whose loss decreases T1D incidence, may also dampen β-cell gene expression and function. Future directions will include comparative NOD and NOD.Ncf1m[1]J single cell transcriptomics to determine cell type specific transcriptional signatures between islet and immune cell subtypes. Presentation: 6/2/2024

B-255 Identification of the protein expression of Androgen Receptor variants using Targeted proteomics in clinical Castration Resistant Prostate Cancer models

Abstract Background Castration Resistant Prostate Cancer (CRPC) is a treatment resistant form of prostate cancer (PCa). Currently, there is not a way to identify which patients will develop this resistance before full blown CRPC develops. Therefore, all PCa treatment approaches are similar yet this results in tumor regression in some cases and progression in others. Targeting the androgen receptor (AR) is still the main focus of current therapies even in CRPC. Emergence of AR splice variants (AR-Vs) after initial treatment is thought to be one of the primary mechanisms of resistance. AR-Vs lack the ligand binding domain rendering Androgen Deprivation Therapy (ADT) ineffective in tumors expressing these variants. Recent work has identified the DNA and RNA species of ARVs in CRPC but investigation into whether the protein is translated are unknown. One exception is the approval of an antibody test that detects a specific AR-v, AR-v7, from the blood of PC patients and predicts ADT response. However, there are instances where a patient may not express ARv7 and are still resistant to ADT. This may suggest that other AR-Vs, not currently detected at the protein level, are important predictors for ADT response. Methods The primary goal of this work is to expand the protein identification of known and unknown AR-Vs that may predict response to ADT using targeted liquid chromatography tandem mass spectrometry (LC-MS/MS). We developed the AR-V targeted LC-MS/MS assay by first designing AR splice variants from unique splice regions via RNA-guided sequences translated to amino acid sequences. The AR-variants full amino acid sequences were then in-silico trypsin digested using Expasy software tool that generated tryptic peptides. Blast analysis of the AR-V peptides was performed where no overlap with other human proteins was observed. These AR-V peptide sequences were commercially synthesized along with heavy isotopically analogs to be used as internal standards in the LC-MS/MS method. The method examined 9 peptides and included 2 to 3 MRM transitions per peptide and calibration curves were constructed using unlabeled peptides. Specimens examined consisted of a panel of PCa cell lines (n= 6), CRPC patient derived xenografts tumors (PDX) (n=4) and a negative control cell line (no androgen receptor expression), Cos-1, which served with a dual function and was used as matrix for peptide MRM optimization experiments. Linearity and sensitivity for each peptide included in the method was examined using calibration curves. Results The targeted MRM approached was successfully achieved for the quantification of 9 peptides from 8 proteins in 6 PCa cell lines and 4 PDX tumor specimens. Out of the 8 proteins evaluated, we observed 3 known targets (AR-exon1, AR-V7 and AR-V12) and 4 novel AR-Vs in 22Rv1 PCa cell lines. Additionally, CRPC PDX were assessed where 3 novel AR-Vs were detected. Conclusions These preliminary results using a LC-MS/MS platform show promising identification and quantification of novel AR-Vs that have not been measured before at the protein level. Subsequent analysis of larger cohorts will further elucidate AR-Vs role in PCa treatment resistance mechanisms and possibly assist in future treatment approaches.

358 (PB346): A novel small molecule inhibitor of PARG, YL-18319, promotes tumor regression in BRCAmutated, Homologous Recombination Deficient, and PARP-inhibitor resistant cancer models

358 (PB346): A novel small molecule inhibitor of PARG, YL-18319, promotes tumor regression in BRCAmutated, Homologous Recombination Deficient, and PARP-inhibitor resistant cancer models

Analysis and estimation of power losses in high-power, high-frequency transformers for isolated DC/DC converters

The paper presents an in-depth analysis of the power losses in the windings and the cores of two different transformers as applied to a phase-shifted full bridge (PSFB) converter at the power level of 20–25 kW and the switching frequency of 50 kHz. The main difference in the construction of the considered devices was the method of winding realization as well as the shape and material of the cores. The influence of the winding geometry on the conduction losses was analyzed, and the losses in the cores were analytically estimated, taking into account the operating conditions of these elements in the full-bridge system with phase-shift modulation. Original resistive models of windings made of cooper sheets are presented. The obtained results were verified by experimental tests carried out in an isolated full-bridge DC/DC converter.

Preclinical Characterization of ARX517, a Site-specific Stable PSMA-Targeted Antibody Drug Conjugate for Treatment of Metastatic Castration-Resistant Prostate Cancer.

Metastatic castration-resistant prostate cancer (mCRPC) is an advanced disease in which patients ultimately fail standard of care androgen-deprivation therapies and exhibit poor survival rates. The prostate-specific membrane antigen (PSMA) has been validated as a mCRPC tumor antigen with over-expression in tumors and low expression in healthy tissues. Using our proprietary technology for incorporating synthetic amino acids (SAAs) into proteins at selected sites, we have developed ARX517, an antibody drug conjugate (ADC) which is composed of a humanized anti-PSMA antibody site-specifically conjugated to a tubulin inhibitor at a drug-to-antibody ratio of 2. After binding PSMA, ARX517 is internalized and catabolized, leading to cytotoxic payload delivery and apoptosis. To minimize premature payload release and maximize delivery to tumor cells, ARX517 employs a non-cleavable PEG linker and stable oxime conjugation enabled via SAA protein incorporation to ensure its overall stability. In vitro studies demonstrate that ARX517 selectively induces cytotoxicity of PSMA-expressing tumor cell lines. ARX517 exhibited a long terminal half-life and high serum exposure in mice, and dose-dependent anti-tumor activity in both enzalutamide-sensitive and -resistant CDX and PDX prostate cancer models. Repeat dose toxicokinetic studies in non-human primates demonstrated ARX517 was tolerated at exposures well above therapeutic exposures in mouse pharmacology studies, indicating a wide therapeutic index. In summary, ARX517 inhibited tumor growth in diverse mCRPC models, demonstrated a tolerable safety profile in monkeys, and had a wide therapeutic index based on preclinical exposure data. Based on the encouraging preclinical data, ARX517 is currently being evaluated in a Phase 1 clinical trial ([NCT04662580]).

ORIC-101, a Glucocorticoid Receptor Antagonist, in Combination with Nab-Paclitaxel in Patients with Advanced Solid Tumors.

In preclinical models, glucocorticoid receptor (GR) signaling drives resistance to taxane chemotherapy in multiple solid tumors via upregulation of antiapoptotic pathways. ORIC-101 is a potent and selective GR antagonist that was investigated in combination with taxane chemotherapy as an anticancer regimen preclinically and in a phase 1 clinical trial. The ability of ORIC-101 to reverse taxane resistance was assessed in cell lines and xenograft models, and a phase 1 study (NCT03928314) was conducted in patients with advanced solid tumors to determine the dose, safety, and antitumor activity of ORIC-101 with nab-paclitaxel. ORIC-101 reversed chemoprotection induced by glucocorticoids in vitro and achieved tumor regressions when combined with paclitaxel in both taxane-naïve and -resistant xenograft models. In the phase 1 study, 21 patients were treated in dose escalation and 62 patients were treated in dose expansion. All patients in dose expansion had previously progressed on a taxane-based regimen. In dose escalation, five objective responses were observed. A preplanned futility analysis in dose expansion showed a 3.2% (95% confidence interval, 0.4-11.2) objective response rate with a median progression-free survival of 2 months (95% confidence interval, 1.8-2.8) across all four cohorts, leading to study termination. Pharmacodynamic analysis of tissue and plasma showed GR pathway downregulation in most patients in cycle 1. ORIC-101 with nab-paclitaxel showed limited clinical activity in taxane-resistant solid tumors. Despite clear inhibition of GR pathway signaling, the insufficient clinical signal underscores the challenges of targeting a single resistance pathway when multiple mechanisms of resistance may be in play. Glucocorticoid receptor (GR) upregulation is a mechanism of resistance to taxane chemotherapy in preclinical cancer models. ORIC-101 is a small molecule GR inhibitor. In this phase 1 study, ORIC-101 plus nab-paclitaxel did not show meaningful clinical benefit in patients who previously progressed on taxanes despite successful GR pathway downregulation.

The efficacy of gemcitabine and docetaxel chemotherapy for the treatment of relapsed and refractory osteosarcoma: A systematic review and pre-clinical study.

Osteosarcoma is the most common primary malignancy of the bone. There is a lack of effective treatments for patients who experience relapsed osteosarcoma. One treatment for relapsed patients is gemcitabine and docetaxel combination chemotherapy (GEMDOX). This systematic review aimed to establish the efficacy of this chemotherapy regimen, as well as identify the common severe toxicities that are associated with it. Resistant osteosarcoma cell lines developed from MG-63 and HOS-143B were used to represent relapsed osteosarcoma patients in a pre-clinical study. We identified 11 retrospective and Phase II studies that were suitable for inclusion in our review. 10.65% of patients had a response to gemcitabine and docetaxel combination therapy and the disease control rate was 35% (n = 197). 36%, 35.3% and 18.04% of patients experienced grade 3 or 4 neutropenia, thrombocytopenia and anaemia respectively (n = 133). Male patients (X2 = 9.14, p < 0.05) and those below the age of 18 (X 2 = 10.94, p < 0.05) responded better to GEMDOX treatment than females and patients older than 18 years. The resistant osteosarcoma cell lines remained sensitive to either single-agent gemcitabine, docetaxel, and the combination of both. Cisplatin-resistant models (MG-63/CISR8 & HOS-143B/CISR8) were the most responsive to GEMDOX treatment compared to doxorubicin, methotrexate, and triple-combination resistant models. GEMDOX treatment has potential efficacy in relapsed osteosarcoma patients especially those with cisplatin resistance. To directly compare the efficacy of GEMDOX therapy against other therapies randomised phase III clinical trials with adequate patient follow up must be performed to improve treatment options for osteosarcoma.

Neratinib plus dasatinib is highly synergistic in HER2-positive breast cancer in vitro and in vivo

BackgroundHER2-targeted therapies have revolutionised the treatment of HER2-positive breast cancer. However, de novo resistance or the emergence of acquired resistance is a persistent clinical problem. Here we report that neratinib, an irreversible pan-HER inhibitor, in combination with the multi-kinase inhibitor dasatinib, currently used to treat certain leukemias, has strong anti-proliferative effects against models of HER2-positive breast cancer that are innately resistant to trastuzumab or have acquired resistance to neratinib. MethodsNeratinib plus dasatinib was examined in a panel of 20 breast cancer cell lines, including HER2-positive, estrogen-receptor-positive, triple negative, and acquired HER2-targeted therapy resistant models. Drug effects on migration and apoptosis induction was evaluated and signaling alterations were determined by reverse phase protein array (RPPA). In vivo efficacy was examined using orthotopically-implanted HCC1954 cells. ResultsSynergy was observed in cell lines innately resistant to trastuzumab, models with acquired resistance to neratinib, and in triple negative breast cancer cell lines. Further investigation showed that neratinib plus dasatinib induced apoptosis and inhibited cell migration to a greater degree than either drug alone. RPPA revealed that the combination caused suppression of key survival signaling through EGFR, Akt, and MAPK inhibition. In vivo, neratinib plus dasatinib was well tolerated and had a prolonged anti-tumor effect against HCC1954 xenografts. ConclusionsThis study provides a strong pre-clinical rationale for the clinical investigation neratinib and dasatinib in HER2+ breast cancer.

Targeting Super-Enhancer-Driven Transcriptional Dependencies Suppresses Aberrant Hedgehog Pathway Activation and Overcomes Smoothened Inhibitor Resistance.

Aberrant activation of the Hedgehog (Hh) signaling pathway plays important roles in oncogenesis and therapeutic resistance in several types of cancer. The clinical application of FDA-approved Hh-targeted smoothened inhibitors (SMOi) is hindered by the emergence of primary or acquired drug resistance. Epigenetic and transcriptional-targeted therapies represent a promising direction for developing improved anti-Hh therapies. In this study, we integrated epigenetic/transcriptional-targeted small-molecule library screening with CRISPR/Cas9 knockout library screening and identified CDK9 and CDK12, two transcription elongation regulators, as therapeutic targets for antagonizing aberrant Hh activation and overcoming SMOi resistance. Inhibition of CDK9 or CDK12 potently suppressed Hh signaling and tumor growth in various SMOi responsive or resistant Hh-driven tumor models. Systemic epigenomic profiling elucidated the Hh-driven super-enhancer (SE) landscape and identified IRS1, encoding a critical component and cytoplasmic adaptor protein of the insulin-like growth factor (IGF) pathway, as an oncogenic Hh-driven SE target gene and effective therapeutic target in Hh-driven tumor models. Collectively, this study identifies SE-driven transcriptional dependencies that represent promising therapeutic vulnerabilities for suppressing the Hh pathway and overcoming SMOi resistance. As CDK9 and IRS inhibitors have already entered human clinical trials for cancer treatment, these findings provide comprehensive preclinical support for developing trials for Hh-driven cancers. Significance: Dissecting transcriptional dependencies driven by super-enhancers uncovers therapeutic targets in Hedgehog-driven cancers and identifies strategies for overcoming resistance to smoothened inhibitors.

The first-in-class pro-apoptotic peptide PEP-010 is effective in monotherapy and in combination with paclitaxel on resistant ovarian adenocarcinoma cell models.

Ovarian adenocarcinoma is the gynecological malignancy with the worst prognosis and the highest mortality rate. In the first stages of treatment, chemotherapy results effective, but its prolonged use and high doses lead to the appearance of resistance to treatments and relapse in most patients, representing a major challenge for clinicians. We developed PEP-010, a cell penetrating proapoptotic peptide disrupting the protein-protein interaction between caspase-9 and protein phosphatase 2A, thereby leading to the recovery of their activity in the apoptotic pathway. MTT assay or Annexin-V/Propidium Iodide staining and flow cytometry analysis were used to assess sensitivity to chemotherapies and apoptosis after treatment with PEP-010 in monotherapy or in combination with paclitaxel in ovarian carcinoma cell lines. DNA damage was assessed by immunofluorescence using γH2AX marker. We show here that PEP-010 effectively induces cell death in monotherapy on in up to 55% of cells from ovarian adenocarcinoma cell models resistant to different chemotherapies. Moreover, when used in combination with paclitaxel, one of the therapeutic options for recurrent ovarian carcinoma, PEP-010 showed a beneficial effect leading to the reduction of the IC50 of paclitaxel of 2.2 times and to apoptosis in 87% of cells. The described results suggest the potential therapeutic interest for PEP-010 and lead to the choice of ovarian adenocarcinoma as one of the major indications of the ongoing clinical trial.

Sonodynamic Treatment Triggers Cancer Cell Killing by Doxorubicin in P‐Glycoprotein‐Mediated Multidrug Resistant Cancer Models

Sonodynamic Treatment Triggers Cancer Cell Killing by Doxorubicin in P‐Glycoprotein‐Mediated Multidrug Resistant Cancer Models