Cancer Models Research Articles

MYBL2 Drives Prostate Cancer Plasticity: Inhibiting its Transcriptional Target CDK2 for RB1-Deficient Neuroendocrine Prostate Cancer.

Phenotypic plasticity is a recognized mechanism driving therapeutic resistance in prostate cancer (PCa) patients. While underlying molecular causations driving phenotypic plasticity have been identified, therapeutic success is yet to be achieved. To identify putative master regulator transcription factors (MR-TF) driving phenotypic plasticity in PCa, this work utilized a multiomic approach using genetically engineered mouse models of prostate cancer combined with patient data to identify MYBL2 as a significantly enriched transcription factor in PCa exhibiting phenotypic plasticity. Genetic inhibition of Mybl2 using independent murine PCa cell lines representing phenotypic plasticity demonstrated Mybl2 loss significantly decreased in vivo growth as well as cell fitness and repressed gene expression signatures involved in pluripotency and stemness. Because MYBL2 is currently not druggable, a MYBL2 gene signature was employed to identify cyclin-dependent kinase-2 (CDK2) as a potential therapeutic target. CDK2 inhibition phenocopied genetic loss of Mybl2 and significantly decreased in vivo tumor growth associated with enrichment of DNA damage. Together, this work demonstrates MYBL2 as an important MR-TF driving phenotypic plasticity in PCa. Further, high MYBL2 activity identifies PCa that would be responsive to CDK2 inhibition.

The effects of carbon-ion beam irradiation on three-dimensional in vitro models of normal oral mucosa and oral cancer: development of a novel tool to evaluate cancer therapy.

Given that the original tumor microenvironment of oral cancer cannot be reproduced, predicting the therapeutic effects of irradiation using monolayer cultures and animal models of ectopic tumors is challenging. Unique properties of carbon-ion irradiation (CIR) characterized by the Bragg peak exert therapeutic effects on tumors and prevent adverse events in surrounding normal tissues. However, the underlying mechanism remains unclear. The biological effects of CIR were evaluated on three-dimensional (3D) in vitro models of normal oral mucosa (NOMM) and oral cancer (OCM3 and OCM4) consisting of HSC-3 and HSC-4 cells. A single 10- or 20-Gy dose of CIR was delivered to NOMM, OCM3, and OCM4 models. Histopathological and histomorphometric analyses and labeling indices for Ki-67, γH2AX, and TUNEL were examined after CIR. The concentrations of high mobility group box 1 (HMGB1) were measured. NOMM exhibited epithelial thinning after CIR, which could be caused by the decreased presence of Ki-67-labeled basal cells. The relative proportion of the thickness of cancer cells to the underlying stroma in cancer models decreased after CIR. This finding appeared to be supported by changes in the three labeling indices, indicating CIR-induced cancer cell death, mostly via apoptosis. Furthermore, the three indices and the HMGB1 release levels significantly differed among the OCM4 that received different doses and with different incubation times after CIR while those of the OCM3 models did not, suggesting more radiosensitivity in the OCM4. The three 3D in vitro models can be a feasible and novel tool to elucidate radiation biology.

IPSC-derived lung and lung cancer organoid model to evaluate cisplatin encapsulated autologous iPSC-derived mesenchymal stromal cell-isolated extracellular vesicles

BackgroundLung cancer remains a leading cause of cancer-related mortality globally. Although recent therapeutic advancements have provided targeted treatment approaches, the development of resistance and systemic toxicity remain primary concerns. Extracellular vesicles (EVs), especially those derived from mesenchymal stromal cells (MSC), have gained attention as promising drug delivery systems, offering biocompatibility and minimal immune responses. Recognizing the limitations of conventional 2D cell culture systems in mimicking the tumor microenvironment, this study aims to describe a proof-of-principle approach for using patient-specific organoid models for both lung cancer and normal lung tissue and the feasibility of employing autologous EVs derived from induced pluripotent stem cell (iPSC)-MSC in personalized medicine approaches.MethodsFirst, we reprogrammed healthy fibroblasts into iPSC. Next, we differentiated patient-derived iPSC into branching lung organoids (BLO) and generated patient-matched lung cancer organoids (LCO) from patient-derived tumor tissue. We show a streamlined process of MSC differentiation from iPSC and EV isolation from iPSC-MSC, encapsulated with 0.07 µg/mL of cytotoxic agent cisplatin and applied to both organoid models. Cytotoxicity of cisplatin and cisplatin-loaded EVs was recorded with LDH and CCK8 tests.ResultsFibroblast-derived iPSC showed a normal karyotype, pluripotency staining, and trilineage differentiation. iPSC-derived BLO showed expression of lung markers, like TMPRSS2 and MUC5A while patient-matched LCO showed expression of Napsin and CK5. Next, we compared the effects of iPSC-MSC derived EVs loaded with cisplatin against empty EVs and cisplatin alone in lung cancer organoid and healthy lung organoid models. As expected, we found a cytotoxic effect when LCO were treated with 20 µg/mL cisplatin. Treatment of LCO and BLO with empty EVs resulted in a cytotoxic effect after 24 h. However, EVs loaded with 0.07 µg/mL cisplatin failed to induce any cytotoxic effect in both organoid models.ConclusionWe report on a proof-of-principle pipeline towards using autologous or allogeneic iPSC-MSC EVs as drug delivery tests for lung cancer in future. However, due to the time and labor-intensive processes, we conclude that this pipeline might not be feasible for personalized approaches at the moment.

Natural Derivatives of Selective HDAC8 Inhibitors with Potent in Vivo Antitumor Efficacy against Breast Cancer.

HDAC8 is a therapeutic target with great promise for breast cancer. Here, we reported a novel compound corallorazine D from Nocardiopsis sp. XZB108, selectively inhibited HDAC8 (IC50 = 0.90 ± 0.014 μM), suggesting that it may be a promising nonhydroxamate HDAC8 inhibitor. Upon additional modifications of corallorazine D, a candidate compound 5k, demonstrated remarkable inhibitory potency against HDAC8 (IC50 = 0.12 ± 0.01 nM), 89-fold superior to PCI-34051. The selectivity of 5k was at least 439-fold, superior to corallorazine D, confirming the efficacy of our modifications. In an orthotopic mouse model of breast cancer, 5k displayed nearly 4-fold superior antitumor activity than SAHA. Furthermore, 5k triggered antitumor immunity by activating T cells. Treatment with 5k significantly increased the proportion of M1 macrophages and decreased the proportion of M2 macrophages (M1/M2 ratio = 2.67 ± 0.25). 5k represents a promising compound for further investigation as a potential treatment for breast cancer.

Sacituzumab Govitecan in patients with breast cancer brain metastases and recurrent glioblastoma: a phase 0 window-of-opportunity trial

Sacituzumab Govitecan (SG) is an antibody-drug conjugate that has demonstrated efficacy in patients with TROP-2 expressing epithelial cancers. In a xenograft model of intracranial breast cancer, SG inhibited tumor growth and increased mouse survival. We conducted a prospective window-of-opportunity trial (NCT03995706) at the University of Texas Health Science Center at San Antonio to examine the intra-tumoral concentrations and intracranial activity of SG in patients undergoing craniotomy for breast cancer with brain metastases (BCBM) or recurrent glioblastoma (rGBM). We enrolled 25 patients aged ≥18 years diagnosed with BCBM and rGBM to receive a single intravenous dose of SG at 10 mg/kg given one day before resection and continued on days 1 and 8 of 21-day cycles following recovery. The PFS was 8 months and 2 months for BCBM and rGBM cohorts, respectively. The OS was 35.2 months and 9.5 months, respectively. Grade≥3 AE included neutropenia (28%), hypokalemia (8%), seizure (8%), thromboembolic event (8%), urinary tract infection (8%) and muscle weakness of the lower limb (8%). In post-surgical tissue, the median total SN-38 was 249.8 ng/g for BCBM and 104.5 ng/g for rGBM, thus fulfilling the primary endpoint. Biomarker analysis suggests delivery of payload by direct release at target site and that hypoxic changes do not drive indirect release. Secondary endpoint of OS was 35.2 months for the BCBM cohort and 9.5 months for rGBM. Non-planned exploratory endpoint of ORR was 38% for BCBM and 29%, respectively. Exploratory endpoint of Trop-2 expression was observed in 100% of BCBM and 78% of rGBM tumors. In conclusion, SG was found to be well tolerated with adequate penetration into intracranial tumors and promising preliminary activity within the CNS. Trial Registration: Trial (NCT03995706) enrolled at Clinical Trials.gov as Neuro/Sacituzumab Govitecan/Breast Brain Metastasis/Glioblastoma/Ph 0: https://clinicaltrials.gov/study/NCT03995706?cond=NCT03995706.

Prevention of chemotherapy-related bone loss with doxorubicin-loaded solid lipid nanoparticles.

Aim: Breast cancer and its metastases involve high mortality even with advances in chemotherapy. Solid lipid nanoparticles provide a platform for drug delivery, reducing side effects and treatment-induced bone loss. A solid nanoparticle containing doxorubicin was evaluated for its ability to prevent bone loss in a pre-clinical breast cancer model. Methods: We investigated the effects of SLNDox in an aggressive metastatic stage IV breast cancer model, which has some important features that are interesting for bone loss investigation. This study evaluates bone loss prevention potential from solid lipid nanoparticles containing doxorubicin breast cancer treatment, an evaluation of the attenuation of morphological changes in bone tissue caused by the treatment and the disease and an assessment of bone loss imaging using computed tomography and electron microscopy. Results: Chemotherapy-induced bone loss was also observed in tumor-free animals; a solid lipid nanoparticle containing doxorubicin prevented damage to the growth plate and to compact and cancellous bones in the femur of tumor-bearing and healthy animals. Conclusion: The association of solid lipid nanoparticles with chemotherapeutic drugs with proven efficacy promotes the prevention of serious consequences of chemotherapy, reducing tumor progression, increasing quality of life and improving prognosis and survival.

Liver X Receptors Enhance Epithelial to Mesenchymal Transition in Metastatic Prostate Cancer Cells

Prostate cancer (PCa) is one of the most common cancers in men. Metastasis is the leading cause of death in prostate cancer patients. One of the crucial processes involved in metastatic spread is the “epithelial–mesenchymal transition” (EMT), which allows cells to acquire the ability to invade distant organs. Liver X Receptors (LXRs) are nuclear receptors that have been demonstrated to regulate EMT in various cancers, including hepatic cancer. Our study reveals that the LXR pathway can control pro-invasive cell capacities through EMT in prostate cancer, employing ex vivo and in vivo approaches. We characterized the EMT status of the commonly used LNCaP, DU145, and PC3 prostate cancer cell lines through molecular and immunohistochemistry experiments. The impact of LXR activation on EMT function was also assessed by analyzing the migration and invasion of these cell lines in the absence or presence of an LXR agonist. Using in vivo experiments involving NSG-immunodeficient mice xenografted with PC3-GFP cells, we were able to study metastatic spread and the effect of LXRs on this process. LXR activation led to an increase in the accumulation of Vimentin and Amphiregulin in PC3. Furthermore, the migration of PC3 cells significantly increased in the presence of the LXR agonist, correlating with an upregulation of EMT. Interestingly, LXR activation significantly increased metastatic spread in an NSG mouse model. Overall, this work identifies a promoting effect of LXRs on EMT in the PC3 model of advanced prostate cancer.

Gastrointestinal Cancer Patient Derived Organoids at the Frontier of Personalized Medicine and Drug Screening

Cancer is a leading cause of death worldwide. Around one-third of the total global cancer incidence and mortality are related to gastrointestinal (GI) cancers. Over the past few years, rapid developments have been made in patient-derived organoid (PDO) models for gastrointestinal cancers. By closely mimicking the molecular properties of their parent tumors in vitro, PDOs have emerged as powerful tools in personalized medicine and drug discovery. Here, we review the current literature on the application of PDOs of common gastrointestinal cancers in the optimization of drug treatment strategies in the clinic and their rising importance in pre-clinical drug development. We discuss the advantages and limitations of gastrointestinal cancer PDOs and outline the microfluidics-based strategies that improve the throughput of PDO models in order to extract the maximal benefits in the personalized medicine and drug discovery process.

A Fully Integrated Conformal Wearable Ultrasound Patch for Continuous Sonodynamic Therapy.

Cancer treatment is a continuous process, that the current therapy cannot meet the requirement well, including radiotherapy and chemotherapy. Wearable ultrasound device has the potential for continuous sonodynamic therapy due to its portability. However, the miniaturization of ultrasonic probe, system integration of device, and the strategy of continuous treatment are still urgent issues to be addressed. Herein, a portable wearable antitumor system is introduced, which utilizes a custom-developed multiplexed ultrasonic patch array (CWUS Patch) to accurately focus ultrasound on the lesion site and controllably stimulate sonosensitizer to produce a large amount of toxic reactive oxygen species (ROS). The system enables dynamic control of the ultrasound patches and allows real-time adjustments to optimize their performance in various applications, providing greater flexibility and precision in healthcare technology. Furthermore, the excellent penetration property of ultrasound into tumor tissues that induce synchronous apoptosis of tumor cells from the inside out is verified through a mouse model of breast cancer. This fully integrated conformal wearable ultrasound system provides a promising approach to noninvasively, continuously, and efficiently treat deep tumors.

Preclinical Efficacy of VTX-0811: A Humanized First-in-Class PSGL-1 mAb Targeting TAMs to Suppress Tumor Growth

Omnipresent suppressive myeloid populations in the tumor microenvironment limit the efficacy of T-cell-directed immunotherapies, become more inhibitory after administration of T-cell checkpoint inhibitors, and are overall associated with worse survival of cancer patients. In early clinical trials, positive outcomes have been demonstrated for therapies aimed at repolarizing suppressive myeloid populations in the tumor microenvironment. We have previously described the key role of P-selectin glycoprotein ligand-1 (PSGL-1) in maintaining an inhibitory state of tumor-associated macrophages (TAMs), most of which express high levels of PSGL-1. Here we describe a novel, first-in-class humanized high-affinity monoclonal antibody VTX-0811 that repolarizes human macrophages from an M2-suppressive phenotype towards an M1 inflammatory phenotype, similar to siRNA-mediated knockdown of PSGL-1. VTX-0811 binds to PSGL-1 of human and cynomolgus macaque origins without inhibiting PSGL-1 interaction with P- and L-Selectins or VISTA. In multi-cellular assays and in patient-derived human tumor cultures, VTX-0811 leads to the induction of pro-inflammatory mediators. RNAseq data from VTX-0811 treated ex vivo tumor cultures and M2c macrophages show similar pathways being modulated, indicating that the mechanism of action translates from isolated macrophages to tumors. A chimeric version of VTX-0811, consisting of the parental murine antibody in a human IgG4 backbone, inhibits tumor growth in a humanized mouse model of cancer. VTX-0811 is exceptionally well tolerated in NHP toxicology assessment and is heading into clinical evaluation after successful IND clearance.

The Anticancer Activity of Monosaccharides: Perspectives and Outlooks

A major hallmark of cancer is the reprogramming of cellular metabolism from oxidative phosphorylation (OXPHOS) to glycolysis, a phenomenon known as the Warburg effect. To sustain high rates of glycolysis, cancer cells overexpress GLUT transporters and glycolytic enzymes, allowing for the enhanced uptake and consumption of glucose. The Warburg effect may be exploited in the treatment of cancer; certain epimers and derivatives of glucose can enter cancer cells and inhibit glycolytic enzymes, stunting metabolism and causing cell death. These include common dietary monosaccharides (ᴅ-mannose, ᴅ-galactose, ᴅ-glucosamine, ʟ-fucose), as well as some rare monosaccharides (xylitol, ᴅ-allose, ʟ-sorbose, ʟ-rhamnose). This article reviews the literature on these sugars in in vitro and in vivo models of cancer, discussing their mechanisms of cytotoxicity. In addition to this, the anticancer potential of some synthetically modified monosaccharides, such as 2-deoxy-ᴅ-glucose and its acetylated and halogenated derivatives, is reviewed. Further, this article reviews how certain monosaccharides can be used in combination with anticancer drugs to potentiate conventional chemotherapies and to help overcome chemoresistance. Finally, the limitations of administering two separate agents, a sugar and a chemotherapeutic drug, are discussed. The potential of the glycoconjugation of classical or repurposed chemotherapy drugs as a solution to these limitations is reviewed.

Folate Receptor β (FRβ) Expression on Myeloid Cells and the Impact of Reticuloendothelial System on Folate-Functionalized Nanoparticles' Biodistribution in Cancer.

Folate uptake is largely mediated by folate receptor (FR)β, encoded by FOLR2 gene, in myeloid immune cells such as granulocytes, monocytes, and especially in macrophages that constitute the reticuloendothelial system (RES) and infiltrate the tumor microenvironment. Since the myeloid immune compartment dynamically changes during tumorigenesis, it is critical to assess the infiltration status of the tumors by FRβ-expressing myeloid cells to better define the targeting efficacy of folate-functionalized drug delivery systems. On the other hand, clearance by RES is a major limitation for the targeting efficacy of nanoparticles decorated with folate. Therefore, the aims of this study are (i) to determine the amount and subtypes of FRβ+ myeloid cells infiltrating the tumors at different stages, (ii) to compare the amount and subtype of FRβ+ myeloid cells in distinct organs of tumor-bearing and healthy animals, (iii) to test if the cancer-targeting efficacy and biodistribution of a prototypic folate-functionalized nanoparticle associates with the density of FRβ+ myeloid cells. Here, we report that myeloid cell infiltration was enhanced and FRβ was upregulated at distinct stages of tumorigenesis in a mouse breast cancer model. The CD206+ subset of macrophages highly expressed FRβ, prominently both in tumor-bearing and healthy mice. In tumor-bearing mice, the amount of all myeloid cells, but particularly granulocytes, was remarkably increased in the tumor, liver, lungs, spleen, kidneys, lymph nodes, peritoneal cavity, bone marrow, heart, and brain. Compared with macrophages, the level of FRβ was moderate in granulocytes and monocytes. The density of FRβ+ immune cells in the tumor microenvironment was not directly associated with the tumor-targeting efficacy of the folate-functionalized cyclodextrin nanoparticles. The lung was determined as a preferential site of accumulation for folate-functionalized nanoparticles, wherein FRβ+CD206+ macrophages significantly engulfed cyclodextrin nanoparticles. In conclusion, our results demonstrate that the tumor formation augments the FR levels and alters the infiltration and distribution of myeloid immune cells in all organs which should be considered as a major factor influencing the targeting efficacy of nanoparticles for drug delivery.

The highly metastatic 4T1 breast carcinoma model possesses features of a hybrid epithelial-mesenchymal phenotype.

Epithelial-mesenchymal transitions (EMTs) are thought to promote metastasis via downregulation of E-cadherin and upregulation of mesenchymal markers such as N-cadherin and vimentin. Contrary to this, E-cadherin is retained in many invasive carcinomas and promotes collective cell invasion. To investigate how E-cadherin regulates metastasis, we examined the highly metastatic, E-cadherin-positive murine 4T1 breast cancer model, together with the less metastatic, 4T1-related cell lines, 4T07, 168FARN, and 67NR. We found that 4T1 cells display a hybrid-E/M phenotype with co-expression of epithelial and mesenchymal markers, while 4T07, 168FARN, and 67NR display progressively more mesenchymal phenotypes in vitro that relate inversely to their metastatic capacity in vivo. Using RNA interference and constitutive expression, we demonstrate that the expression level of E-cadherin does not determine 4T1 or 4T07 cell metastatic capacity in mice. Mechanistically, 4T1 cells possess highly dynamic, unstable cell-cell junctions and can undergo collective invasion without E-cadherin downregulation. However, 4T1 orthotopic tumors in vivo also contain subregions of EMT-like loss of E-cadherin. Thus, 4T1 cells function as a model for carcinomas with a hybrid-E/M phenotype that promotes invasion and metastasis.

Natural Killer Cell Regulation of Breast Cancer Stem Cells Mediates Metastatic Dormancy.

Breast cancer patients with estrogen receptor positive tumors face a constant risk of disease recurrence for the remainder of their lives. Dormant tumor cells residing in tissues such as the bone marrow may generate clinically significant metastases many years after initial diagnosis. Previous studies suggest that dormant cancer cells display "stem like" properties (CSCs), which may be regulated by the immune system. To elucidate the role of the immune system in controlling dormancy and its escape, we studied dormancy in immunocompetent, syngeneic mouse breast cancer models. Three mouse breast cancer cell lines, PyMT, Met-1 and D2.0R, contained CSCs that displayed both short- and long-term metastatic dormancy in vivo, which was dependent on the host immune system. Each model was regulated by different components of the immune system. Natural killer (NK) cells were key for the metastatic dormancy phenotype in D2.0R cells. Quiescent D2.0R CSCs were resistant to NK cell cytotoxicity, while proliferative CSCs were sensitive. Resistance to NK cell cytotoxicity was mediated, in part, by expression of BACH1 and SOX2 transcription factors. Expression of STING and STING targets was decreased in quiescent CSCs, and the STING agonist MSA-2 enhanced NK cell killing. Collectively, these findings demonstrate the role of immune regulation of breast tumor dormancy and highlight the importance of utilizing immunocompetent models to study this phenomenon.

Proteomics analysis of carcinogenesis in a rat model of mammary cancer induced by DMBA (7,12-dimethylbenz[a]anthracene)

Background: Mammary cancer, called breast cancer in humans, results from the abnormal growth of cells in the mammary glands that attack the surrounding tissue. The process of carcinogenesis at the molecular level can be monitored through the production of proteins as biomarkers for carcinogenesis. 7,12-Dimethylbenz[a]anthracene (DMBA) is a known carcinogenic compound. This study aimed to analyze the proteomic profile as critical data regarding DMBA-induced carcinogenesis in Sprague‒Dawley rats. Methods: Experimental animals were divided into two groups: a treatment group given DMBA at a dose of 10 mg/kg (intramammary) at intervals of 48 hours for a total of 10 doses, and a negative control group that was not given any treatment. Measurement of the total protein concentration was carried out using a spectrophotometer, and the data were analyzed using a t-test, while the characterization of protein profiles was carried out based on molecular weight data using SDS‒PAGE. Mammary gland histopathology was evaluated by hematoxylin and eosin (H&E) staining. Results: The results showed a significant (p<0.05) increase of 27% in the total protein concentration in the rat mammary cancer model. The results of proteomic characterization showed a protein profile containing proteins of 187, 169, 68, 64, 53, 41, 24, 18, and 14 kDa, which were suspected to be HER-2, Nischarin, COX-2, Albumine, Vimentin, ACTB, TNF, p16, and fatty acid binding protein 3 (FABP3), respectively. Histopathology of the mammary glands showed an irregular and indistinct arrangement of the alveoli and extensive epithelial cell proliferation from the surface to the lumen of the mammary ducts, and the mammary stroma showed the formation of new epithelial cells, which were cancer cells that spread to surrounding tissue. Conclusions: The proteomic profile was strongly associated with morphological alterations in mammary carcinogenesis in a rat model of DMBA-induced mammary cancer.

Combining iRGD with HuFOLactis enhances antitumor potency by facilitating immune cell infiltration and activation

ABSTRACT Multiple research studies have demonstrated the efficacy of lactic acid bacteria in boosting both innate and adaptive immune responses. We have created a Lactococcus lactis variant that produces a modified combination protein with Fms-like tyrosine kinase 3 ligand and co-stimulator O × 40 ligand, known as HuFOLactis. The genetically modified variant was purposely created to activate T cells, NK cells, and DC cells in a laboratory setting. Furthermore, we explored the possibility of using the tumor-penetrating peptide iRGD to deliver HuFOLactis-activated immune cells to hard-to-reach tumor areas. Following brief stimulation with HuFOLactis, immune cell phenotypes and functions were assessed using flow cytometry. Confocal microscopy was employed to demonstrate the infiltrative and cytotoxic capabilities of iRGD-modified HuFOLactis-activated immune cells within tumor spheroids. The efficacy of iRGD modified HuFOLactis-activated immune cells against tumors was assessed in xenograft mouse models. HuFOLactis treatment resulted in notable immune cell activation, demonstrated by elevated levels of CD25, CD69, and CD137. Additionally, these activated immune cells showed heightened cytokine production and enhanced cytotoxicity against MKN45 cell lines. Incorporation of the iRGD modification facilitated the infiltration of HuFOLactis-activated immune cells into multicellular spheroids (MCSs). Additionally, immune cells activated by HuFOLactis and modified with iRGD, in combination with anti-PD-1 treatment, effectively halted tumor growth and prolonged survival in a mouse model of gastric cancer.

The elasticity of silicone-stabilized liposomes has no impact on their in vivo behavior

BackgroundThe elastomechanical properties of nanocarriers have recently been discussed as important for the efficient delivery of various therapeutics. Some data indicate that optimal nanocarriers’ elasticity can modulate in vivo nanocarrier stability, interaction with phagocytes, and uptake by target cells. Here, we presented a study to extensively analyze the in vivo behavior of LIP-SS liposomes that were modified by forming the silicone network within the lipid bilayers to improve their elastomechanical properties. We verified liposome pharmacokinetic profiles and biodistribution, including retention in tumors on a mouse model of breast cancer, while biocompatibility was analyzed on healthy mice.ResultsWe showed that fluorescently labeled LIP-SS and control LIP-CAT liposomes had similar pharmacokinetic profiles, biodistribution, and retention in tumors, indicating that modified elasticity did not improve nanocarrier in vivo performance. Interestingly, biocompatibility studies revealed no changes in blood morphology, liver, spleen, and kidney function but indicated prolonged activation of immune response manifesting in increased concentration of proinflammatory cytokines in sera of animals exposed to all tested liposomes.ConclusionIncorporating the silicone layer into the liposome structure did not change nanocarriers’ characteristics in vivo. Further modification of the LIP-SS surface, including decoration with hydrophilic stealth polymers, should be performed to improve their pharmacokinetics and retention in tumors significantly. Activation of the immune response by LIP-SS and LIP-CAT, resulting in elevated inflammatory cytokine production, requires detailed studies to elucidate its mechanism.Graphical

Co-targeting SOS1 enhances the antitumor effects of KRASG12C inhibitors by addressing intrinsic and acquired resistance.

Combination approaches are needed to strengthen and extend the clinical response to KRASG12C inhibitors (KRASG12Ci). Here, we assessed the antitumor responses of KRASG12C mutant lung and colorectal cancer models to combination treatment with a SOS1 inhibitor (SOS1i), BI-3406, plus the KRASG12C inhibitor, adagrasib. We found that responses to BI-3406 plus adagrasib were stronger than to adagrasib alone, comparable to adagrasib with SHP2 (SHP2i) or EGFR inhibitors and correlated with stronger suppression of RAS-MAPK signaling. BI-3406 plus adagrasib treatment also delayed the emergence of acquired resistance and elicited antitumor responses from adagrasib-resistant models. Resistance to KRASG12Ci seemed to be driven by upregulation of MRAS activity, which both SOS1i and SHP2i were found to potently inhibit. Knockdown of SHOC2, a MRAS complex partner, partially restored response to KRASG12Ci treatment. These results suggest KRASG12C plus SOS1i to be a promising strategy for treating both KRASG12Ci naive and relapsed KRASG12C-mutant tumors.

73 Fasting mediated gut microbiome modulation improves response to immune checkpoint therapy in Renal Cell Cancer

Abstract Background Gut microbiome and microbial metabolome has been shown to be a predictor and modulator of response to immune checkpoint blocker therapy (ICB) in clear cell renal cancer (ccRCC). Based on preliminary data from a prospective clinical study of 100 ccRCC patients, we showed differences in gut microbiome, microbial metabolome and progression free survival. Specifically higher abundance of indole acetic acid, indole acetaldehyde and indole pyruvic acid (IPyA), which represent microbial metabolism of tryptophan were significantly associated with immunotherapy resistance and shorter progression free survival. We hypothesized that time restricted eating would favorably modulate the gut microbiome, microbial metabolome to improve ICB response.We therefore evaluated the efficacy and mechanism of time restricted eating to improve response to immune checkpoint therapy in preclinical kidney cancer models. Methods Specific pathogen free (SPF) BL6 mice were injected subcutaneously with 0.5X106 LVRCC67(Renal adenocarcinoma) cell lines to develop kidney cancer preclinical models followed by randomization into two equal groups when average tumor size reached 100 mm3. Both groups were treated with anti-mouse PD1 twice weekly and daily tyrosine kinase inhibitor (TKI) while group 1 was additionally started on 14 hours of daytime fast(corresponding to period of inactivity), with feeding restricted to ten hours at night, 3 days prior to start of systemic treatment. Tumor volumes were measured twice weekly to evaluate progression free survival (defined as 30% increase in tumor volume), and mice were euthanized at end point, defined as completion of eight doses of antiPD1 treatment. To demonstrate that modulation of gut microbiome is the driving mechanism mediating favorable effect of TRE on ICB response, we conducted fecal microbiota transplant from fasting and non-fasting mice respectively into two groups of germ-free mice. Allowing two weeks for FMT to engraft, mice were injected with RenCa cell lines and subsequently treated with anti-mouse PD1 and TKI, without fasting, once tumors reached an average size of 100 mm 3.Tumors were measured twice weekly to assess PFS, until end point, defined similar to above. Results TRE was associated with significantly longer PFS via modulation of gut microbiome, which is necessary and sufficient to improve ICB response. Tumor growth was significantly slower and PFS significantly longer in SPF TRE mice as compared to non-TRE mice (median PFS 14 days vs 6 days, TRE vs non-TRE, p-0.02). Further GF mice engrafted with fasting microbiome developed significantly smaller tumors, which regressed after treatment, as opposed to those with non-fasting microbiota [(Mean tumor volume-45 mm3 vs 120 mm3, p-0.001 at day15 of injection), median PFS- not reached(NR) vs 7 days, P-0.007)]. Conclusions TRE improves response to ICB in renal cell cancer and can be developed into a cost effective, adjunctive therapy to improve PFS and overall survival of ccRCC patients treated with ICB. Deeper understanding of TRE mediated changes in gut microbiome and microbial metabolome can be leveraged to improve ICB response in patients who are unable to fast.

Targeting fatty acid oxidation enhances response to HER2-targeted therapy

Metabolic reprogramming, a hallmark of tumorigenesis, involves alterations in glucose and fatty acid metabolism. Here, we investigate the role of Carnitine palmitoyl transferase 1a (Cpt1a), a key enzyme in long-chain fatty acid (LCFA) oxidation, in ErbB2-driven breast cancers. In ErbB2+ breast cancer models, ablation of Cpt1a delays tumor onset, growth, and metastasis. However, Cpt1a-deficient cells exhibit increased glucose dependency that enables survival and eventual tumor progression. Consequently, these cells exhibit heightened oxidative stress and upregulated nuclear factor erythroid 2-related factor 2 (Nrf2) activity. Inhibiting Nrf2 or silencing its expression reduces proliferation and glucose consumption in Cpt1a-deficient cells. Combining the ketogenic diet, composed of LCFAs, or an anti-ErbB2 monoclonal antibody (mAb) with Cpt1a deficiency significantly perturbs tumor growth, enhances apoptosis, and reduces lung metastasis. Using an immunocompetent model, we show that Cpt1a inhibition promotes an antitumor immune microenvironment, thereby enhancing the efficacy of anti-ErbB2 mAbs. Our findings underscore the importance of targeting fatty acid oxidation alongside HER2-targeted therapies to combat resistance in HER2+ breast cancer patients.