Head and Neck Cancer Immunotherapy beyond the Checkpoint Blockade

The success of immune checkpoint receptor blockade has brought exciting promises for the treatment of head and neck squamous cell carcinoma (HNSCC). While patients who respond to checkpoint inhibitors tend to develop a durable response, <15% of patients with HNSCC respond to immune checkpoint inhibitors, underscoring the critical need to alleviate cancer resistance to immunotherapy. Major advances have been made to elucidate the intrinsic and adaptive resistance mechanisms to immunotherapy. Central genomic events in HNSCC have been found to possess previously unknown roles in suppressing immune sensing. Such inhibitory function affects both the innate and adaptive arms of tumor-specific immunity. While checkpoint blockade effectively reinvigorates adaptive T-cell responses, additional targeting of the oncogenic inhibitors of innate immune sensing likely informs a novel and potent strategy for immune priming. This review discusses the recent advances on the identification of key HNSCC oncogenes that impair antitumor immunity and emerging immune-priming approaches that sensitize poorly immunogenic HNSCCs to checkpoint blockade. These approaches include but are not limited to cancer vaccine systems utilizing novel type I interferon agonists as immune adjuvants, radiation, DNA damage-inducing agents, and metabolic reprogramming. The goal of these multipronged approaches is to expand tumor-specific effector T-cells, break checkpoint receptor-mediated tolerance, and metabolically support sustained T-cell activation. The translation of therapeutics that reverses oncogenic inhibition of immune sensing requires thorough characterization of the HNSCC regulators of innate immune sensors, development of additional immunocompetent HNSCC mouse models, as well as engineering of more robust immune adjuvant delivery systems. Built on the success of checkpoint blockade, validation of novel immune-priming approaches holds key promises to expand the pool of responders to immunotherapy.

Discovery of a Potent Steroidal Glucocorticoid Receptor Antagonist with Enhanced Selectivity against the Progesterone and Androgen Receptors (OP-3633)

Structure-based modification of mifepristone (1) led to the discovery of novel mifepristone derivatives with improved selectivity profile. Addition of a methyl group at the C10 position of the steroid has a significant impact on progesterone receptor (PR) and androgen receptor (AR) activity. Within this series, OP-3633 (15) emerged as a glucocorticoid receptor (GR) antagonist with increased selectivity against PR and AR, improved cytochrome P450 inhibition profile, and significantly improved pharmacokinetic properties compared to 1. Furthermore, 15 demonstrated substantial inhibition of GR transcriptional activity in the GR positive HCC1806 triple negative breast cancer xenograft model. Overall, compound 15 is a promising GR antagonist candidate to clinically evaluate the impact of GR inhibition in reversal or prevention of therapy resistance.

Abstract 3822: ORIC-101 reverses a GR-driven EMT-like phenotype and sensitizes TNBC cells to chemotherapy

The Glucocorticoid Receptor (GR) is a member of the superfamily of nuclear hormone receptors that is activated by human cortisol and synthetic glucocorticoids such as dexamethasone (Dex). Upon ligand binding, GR translocates to the nucleus and regulates the expression of a wide spectrum of genes involved in diverse biological processes, including inflammation, immunity, metabolism, cell cycle, and differentiation. Dysregulated cortisol levels are associated with poor prognosis, drug resistance, and increased cancer recurrence. Multiple studies have shown that GR inhibition reverses resistance to chemotherapy in cancers of epithelial origin including prostate, bladder, renal, ovarian, pancreatic, and triple negative breast cancer (TNBC).

We have recently reported the discovery of ORIC-101, a potent GR antagonist with a unique cytochrome P450 inhibition profile that makes this compound particularly suitable for combination with taxanes such as paclitaxel (Rew Y et al, 2018). Consistent with previous reports, our data showed that activation of GR promoted growth of TNBC cells in 3D culture conditions and protected TNBC cells from paclitaxel. Treatment with ORIC-101 fully reversed these effects. To understand the molecular basis of the observed GR-mediated chemotherapy resistance, we set out to isolate the pool of TNBC cells that escaped from paclitaxel treatment in the presence of Dex. Molecular profiling of these “chemotherapy escapees” pointed to a number of glucocorticoid-regulated biological pathways, including basal stem cell lineage genes and mesenchymal markers, suggesting the acquisition of an EMT-like phenotype in chemo-resistant cells. In support of this finding, we found using ChIP-seq analysis that GR directly bound within the promoter/enhancer regions of well-established EMT genes such as SNAI2 and FN1, and regulated their expression in response to Dex treatment. Functionally, RNAi-mediated knockdown of SNAI2 partially restored sensitivity to paclitaxel, suggesting that the GR-driven EMT phenotype contributes to paclitaxel resistance in TNBC cells. Consistent with the in vitro observations, immunohistochemical analysis showed that GR activation upregulated the levels of both basal stem cell and mesenchymal markers in “chemotherapy escapees” from paclitaxel-treated TNBC xenografts. Importantly oral administration of ORIC-101 fully blocked these effects.

Altogether, we found that activation of GR drove an EMT-like phenotype in TNBC cells in vitro and in vivo. ORIC-101 reversed these effects and sensitized TNBC cells to chemotherapy. Our findings thus provide mechanistic insights into the role of GR as a mediator of therapy resistance in TNBC. Clinical evaluation is being planned to assess the therapeutic potential of ORIC-101 in combination with standard-of-care chemotherapeutic agents.

Citation Format: Haiying Zhou, Jessica Sun, Wayne Kong, Yosup Rew, Xiaohui Du, John Eksterowicz, Daqing Sun, Qiuping Ye, Omar Kabbarah, Valeria R. Fantin. ORIC-101 reverses a GR-driven EMT-like phenotype and sensitizes TNBC cells to chemotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3822.

Clinical characteristics and treatments of patients with alpha-fetoprotein producing gastric carcinoma

Alpha-fetoprotein (AFP) is a well-known tumor marker of hepatic carcinoma and yolk sac tumor. Alpha-fetoprotein producing gastric carcinoma (AFPGC) is a rare type of gastric cancer with high malignancy and poor prognosis, which make it different from other types of gastric cancer. This rare gastric cancer patient subgroup is likely frequently misdiagnosed which may be related to lack of knowledge of the disease. The purpose of this article is to summarize the mechanism of AFP positive gastric cancer, classification, biological behavior and treatment, in order to assist clinical practitioners to detect AFPGC earlier and treat it better. Previous studies have showed that AFPGC has a complex pathophysiology mechanism. AFPGC is more aggressive and characterized by stronger proliferation, neovascularization, lymphatic invasion and distant metastasis. Furthermore, so far there has been no standard treatment for patients with AFPGC. Nevertheless, our present study summarizes some effective treatments based on previous research outcome. In conclusion, the present study demonstrates that the importance of detecting AFP routinely in serum and tissues in gastric cancer cases, which will greatly improve the diagnosis rate of AFPGC, and in regards to treatment, surgery, chemotherapy, targeted therapy and interventional treatment may have positive impacts on AFPGC treatment outcome. However, further study with a larger sample is required to confirm the reliability and validity of these methods.

A knock-in mouse model of Pendred syndrome with Slc26a4 L236P mutation

SLC26A4 gene mutations lead to Pendred syndrome and non-syndromic hearing loss (DFNB4). The mouse model is well used to study the pathology of Pendred syndrome, however, mice with different Slc26a4 mutations exhibit different phenotypes, and these mice have severe deafness and inner ear malformations that are not imitated less severely Human phenotype. In this study, we generated a knock-in mouse model of Pendred syndrome with Slc26a4 L236P mutation to mimic the most common mutation found in human. Some L236P mice were observed to have significant vestibular dysfunction including torticollis and circling, the giant otoconia and destruction of the otoconial membrane was observed in L236P mice. Unlike other profoundly deafness in Slc26a4 mouse model, L236P mice present mild to profound hearing loss, consistent with the hearing threshold, inner ear hair cells also lost from slight to significant. Together, these data demonstrate that the L236P mouse phenotype is more similar to the human phenotype and should be used as a tool for further research into the human Pendred syndrome.

Clinical and genetic characteristics of familial hypercholesterolemia patients with type 2 diabetes

PURPOSE

Though type 2 diabetes mellitus (T2DM) is an important and independent risk factor for coronary artery disease (CAD) in the general population, the impact of T2DM on CAD in patients with familial hypercholesterolemia (FH) is less understood. Thus, the current study aimed to examine the features of FH patients with T2DM and explore the effects of T2DM on CAD in FH.

METHODS

A total of 289 clinical heterozygous FH (HeFH) patients diagnosed with Dutch Lipid Clinic Criteria were consecutively recruited and divided into a T2DM group (n = 58) and non-T2DM group (n = 231). Clinical characteristics and laboratory findings were compared between the two groups. Target exome sequencing was used for gene mutation analysis.

RESULTS

HeFH patients with T2DM had significantly higher levels of triglycerides, body mass index and free fatty acids than did non-T2DM patients; moreover, patients with T2DM more frequently exhibited hypertension. However, the spectrum of FH-causing mutations was not significantly different (p = 0.061). Notably, patients with T2DM had higher prevalence of CAD (p = 0.012) and higher Gensini Score (p = 0.002). The regression analysis confirmed that HbA1c was an independent risk factor for both the presence and severity of CAD [OR 2.321 (1.098-4.904), p = 0.027; OR 1.349 (1.032-1.762), p = 0.028, respectively] in patients with HeFH.

CONCLUSIONS

Although there were not many differences in the clinical, lipid and genetic aspects of HeFH patients with and without T2DM, T2DM and HbA1c were associated with worse coronary lesions, suggesting that diabetes and the degree of blood glucose control are also important determinants of cardiovascular disease in these patients.

[Application of dental floss traction-assisted endoscopic submucosa dissection to rectal neuroendocrine neoplasm]

Objective: To evaluate the safety and efficacy of dental floss traction-assisted endoscopic submucosal dissection (DFS-ESD) for rectal neuroendocrine neoplasm (NEN). Methods: A retrospective cohort study was performed. Clinical data of rectal NEN patients undergoing ESD at Endoscopy Center of Zhongshan Hospital, Fudan University from January 2016 to December 2017 were retrospectively analyzed. Inclusion criteria: 1) age of 18 to 80 years old; 2) maximal diameter of lesions <1.5 cm; 3) tumor locating in the submucosa without invasion into the muscularis propria; 4) no enlarged lymph nodes around bowel and in abdominal cavity; 5) ESD requested actively by patients. A total of 37 patients were enrolled, including 23 male and 14 female cases with mean age of (56.0±11.3) years. All the lesions were single tumor of stage T1, and the mean size was 0.8±0.2(0.5-1.2) cm. Postoperative pathology revealed all samples as neuroendocrine tumors (NET). Seventeen patients received DFS-ESD treatment (DFS-ESD group) and 20 patient received conventional ESD treatment (conventional ESD group). In DFS-ESD group, after the mucosa was partly incised along the marker dots, the endoscopy was extracted, and the dental floss was tied to one arm of the metallic clip. When the endoscope was reinserted, the hemoclip was attached onto the incised mucosa; another hemoclip was attached onto normal mucosa opposite to the lesion in the same way. The submucosa was clearly exposed with the traction of dental floss and the resection could proceed. The conventional ESD group received the traditional ESD operation procedure. The operation time, modified operation time (remaining time after excluding the assembly time of dental floss traction in DFS-ESD group), en bloc resection rate, R0 resection rate, morbidity of operative complication, recurrence and metastasis were compared between two groups. Results: The average tumor size was (0.8±0.2) cm in DFS-ESD group and (0.7±0.2) cm in conventional ESD group (t=0.425, P=0.673). According to postoperative pathological grading of rectal neuroendocrine neoplasm, 13 were G1 and 4 were G2 in DFS-ESD group, while 17 cases were G1 and 3 cases were G2 in conventional ESD group without significant difference (P=0.680). There were no significant differences in baseline data between in the two groups (all P>0.05). All the basal resection margins were negative, the en bloc resection rate was 100% and the R0 resection rate was 100%. Pathological results showed tumor tissue close to the burning margin in 5 cases of conventional ESD group and in 2 cases of DFS-ESD group (P=0.416). The operation time was (17.9±6.6) minutes in conventional ESD group and (14.7±3.3) minutes in DFS-ESD group (t=1.776, P=0.084). The modified operation time of DFS-ESD group was (11.9±2.8) minutes, which was significantly shorter than (17.9±6.6) minutes in conventional ESD group (t=3.425, P=0.002). The hospital stay was (2.3±0.6) days and (2.0±0.5) days in conventional ESD group and DFS-ESD group, respectively, without significant difference (t=1.436, P=0.160). No patient was transferred to surgery, and no delayed bleeding or perforation occurred in either group. There was no recurrence or primary tumor-related death, and all the patients recovered well during a follow-up period of 14(1-24) months. Conclusion: Dental floss traction-assisted ESD for rectal neuroendocrine neoplasm can simplify operation and ensure negative basal margin.

Acanthopanax senticosus polysaccharide suppressing proliferation and metastasis of the human non-small cell lung cancer NCI-H520 cells is associated with Wnt/β-catenin signaling

Lung cancer (LC) is the highest lethality in all tumors. Non-small cell lung cancer (NSCLC) accounts for about 80% of all LC. Acanthopanax senticosus polysaccharide (ASPS) is extracted from the root of Acanthopanax senticosus (AS). Herein, we examined the effect and molecular mechanism of ASPS on NSCLC. The proliferation, invasion and migration of NCI-H520 cells were detected by cell counting kit-8 (CCK-8), transwell assay and wound healing assay, respectively. The epithelial-mesenchymal transition (EMT) and Wnt/β-catenin pathway-related factors were evaluated using quantitative real-time PCR (QRT-PCR) and western blot assay. Our results observed that ASPS significantly decreased the proliferation of cells at 24 and 48 h. Moreover, ASPS markedly repressed the invasion and migration capacities of cells in a concentration-dependent manner. Besides, ASPS obviously down-regulated the levels of matrix metalloproteinase-2 (MMP-2), MMP-9, fibronectin 1 (FN1), vimentin, wnt3a, phosphorylated-glycogen synthase kinase 3β (p-GSK3β) and cyclin D1, whereas, up-regulating E-cadherin level. The level of GSK3β was not changed in the different groups. ASPS conspicuously inhibited the abilities of proliferation and metastasis in human non-small cell lung cancer cell line NCI-H520 possibly by suppressing Wnt/β-catenin pathway mediated-EMT.

Long-term hydrolytically stable bond formation for future membrane-based deep ocean microfluidic chemical sensors

Future ocean profiling of dissolved inorganic carbon and other analytes will require miniaturised chemical analysis systems based on sealed gas membranes between two fluid channels. However, for long-term deployment in the deep ocean at high pressure, the ability to seal incompatible materials represents an immense challenge. We demonstrate proof of principle high strength bond sealing. We show that polydimethylsiloxane (PDMS) is a preferred membrane material for rapid CO2 transfer, without ion leakage, and report long-term stable bonding of thin PDMS membrane films to inert thermoplastic poly(methyl methacrylate) (PMMA) patterned manifolds. Device channels were filled with 0.01 M NaOH and subjected to repeated tape pull and pressure - flow tests without failure for up to six weeks. Bond formation utilised a thin coating of the aminosilane bis-[3-trimethoxysilylpropyl]amine (BTMSPA) conformally coated onto PMMA channels and surfaces and cured. All surfaces were subsequently plasma treated and devices subject to thermocompressive bond annealing. Successful chemically resistant bonding of membrane materials to thermoplastics opens the possibility of remote environmental chemical analysis and offers a route to float-based depth profiling of dissolved inorganic carbon in the oceans.

Multi-population GWAS and enrichment analyses reveal novel genomic regions and promising candidate genes underlying bovine milk fatty acid composition

Background

The power of genome-wide association studies (GWAS) is often limited by the sample size available for the analysis. Milk fatty acid (FA) traits are scarcely recorded due to expensive and time-consuming analytical techniques. Combining multi-population datasets can enhance the power of GWAS enabling detection of genomic region explaining medium to low proportions of the genetic variation. GWAS often detect broader genomic regions containing several positional candidate genes making it difficult to untangle the causative candidates. Post-GWAS analyses with data on pathways, ontology and tissue-specific gene expression status might allow prioritization among positional candidate genes.

Results

Multi-population GWAS for 16 FA traits quantified using gas chromatography (GC) in sample populations of the Chinese, Danish and Dutch Holstein with high-density (HD) genotypes detects 56 genomic regions significantly associated to at least one of the studied FAs; some of which have not been previously reported. Pathways and gene ontology (GO) analyses suggest promising candidate genes on the novel regions including OSBPL6 and AGPS on Bos taurus autosome (BTA) 2, PRLH on BTA 3, SLC51B on BTA 10, ABCG5/8 on BTA 11 and ALG5 on BTA 12. Novel genes in previously known regions, such as FABP4 on BTA 14, APOA1/5/7 on BTA 15 and MGST2 on BTA 17, are also linked to important FA metabolic processes.

Conclusion

Integration of multi-population GWAS and enrichment analyses enabled detection of several novel genomic regions, explaining relatively smaller fractions of the genetic variation, and revealed highly likely candidate genes underlying the effects. Detection of such regions and candidate genes will be crucial in understanding the complex genetic control of FA metabolism. The findings can also be used to augment genomic prediction models with regions collectively capturing most of the genetic variation in the milk FA traits.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5573-9) contains supplementary material, which is available to authorized users.

Genetic association of DDIT3, RPL23A, SESN2 and NR4A1 genes with milk yield and composition in dairy cattle

Previously, we identified by RNA sequencing that DDIT3, RPL23A, SESN2 and NR4A1 genes were significantly differentially expressed between the mammary glands of lactating Holstein cows with extremely high and low milk protein and fat percentages; thus, these four genes are considered as promising candidates potentially affecting milk yield and composition traits in dairy cattle. In the present study, we further verified whether these genes have genetic effects on milk traits in a Chinese Holstein population. By re-sequencing part of the non-coding and the entire coding regions of the DDIT3, RPL23A, SESN2 and NR4A1 genes, a total of 35 SNPs and three insertions/deletions were identified, of which three were found in DDIT3, 12 in RPL23A, 16 in SESN2 and seven in NR4A1. Moreover, two of the insertions/deletions-g.125714860_125714872del and g.125714806delinsCCCC in SESN2-were novel and have not been reported previously. Subsequent single SNP analyses revealed multiple significant association with all 35 SNPs and three indels regressed against the dairy production traits (P-value = <0.0001-0.0493). In addition, with a linkage disequilibrium analysis, we found one, one, three, and one haplotype blocks in the DDIT3, RPL23A, SESN2 and NR4A1 genes respectively. Haplotype-based association analyses revealed that some haplotypes were also significantly associated with milk production traits (P-value = <0.0001-0.0461). We also found that 12 SNPs and two indels (two in DDIT3, two in RPL23A, nine in SESN2 and one in NR4A1) altered the specific transcription factor binding sites in the promoter, thereby regulating promoter activity, suggesting that they might be promising potential functional variants for milk traits. In summary, our findings first determined the genetic associations of DDIT3, RPL23A, SESN2 and NR4A1 with milk yield and composition traits in dairy cattle and also suggested potentially causal variants, which require in-depth validation.

Silencing of ATPase family AAA domain-containing protein 2 inhibits migration and invasion of colorectal cancer cells

Colorectal cancer is one of the most common malignant tumors with a high rate of distant metastasis, postoperative recurrence and mortality. ATPase family AAA domain-containing protein 2 (ATAD2), a member of ATPase family, is highly expressed in various cancers, including colorectal cancer. However, whether ATAD2 plays a role in the migration and invasion of colorectal cancer cells remains unknown. In this study, we established ATAD2 knockdown in colorectal cancer cell lines by RNA interference and found that silencing of ATAD2 inhibited the migration and invasion ability of Caco-2 and SW-480 cells. Moreover, ATAD2 silencing suppressed epithelial-mesenchymal transition (EMT), and reduced the expression and enzymatic activity of matrix metalloproteinases (MMPs) in Caco-2 and SW-480 cells. In summary, our results suggest that silencing of ATAD2 inhibits migration and invasion of colorectal cancer cells by suppressing EMT and decreasing the activity of MMPs. Hence, ATAD2 could be considered as a novel molecular marker of metastatic colorectal cancer, and it may provide new insights for clinical diagnosis and treatment of colorectal cancer.

[Effects of airway management team in the treatment of severely mass burn patients combined with inhalation injury]

Objective: To explore and analyze the effects of airway management team (AMT) in the treatment of severely mass burn patients combined with inhalation injury. Methods: The clinical data of 58 severely burned patients combined with inhalation injury hospitalized in our unit from January 2012 to August 2014, conforming to the inclusion criteria, were retrospectively analyzed. According to whether airway management was implemented by AMT or not, patients hospitalized from January 2012 to July 2014 were divided into control group (n=27), while patients in Kunshan factory aluminum dust explosion accident hospitalized on 2nd August 2014 were divided into observation group (n=31). Patients in control group received regular airway nursing carried out by nurses on duty, while patients in observation group received specialized airway concentration nursing implemented by AMT. The concrete implementation included overall assessment of patients' airway, elaborate airway care, and controlled management of mechanical ventilation. Arterial blood gas indexes and oxygenation index of patients in the two groups on post injury day (PID) 1, 7, and 14 were compared. Sputum viscosity, ventilator-associated pneumonia (VAP) occurrence rate, and ventilation time of patients in the two groups in post injury week(s) 1, 2, and 3 after admission were monitored and recorded. Survival rates of patients in the two groups were compared. Data were processed with analysis of variance for repeated measurement, t test and Bonferroni correction, chi-square test, and Wilcoxon rank sum test. Results: (1) There were no statistically significant differences in pH value, arterial partial pressure of oxygen (PaO(2)), arterial partial pressure of carbon dioxide (PaCO(2)), arterial oxygen saturation (SaO(2)), and oxygenation index of patients in the two groups on PID 1 (t=0.595, -0.166, 1.518, -0.828, 0.458, P>0.05). The pH values of patients in observation group on PID 7 and 14 were 7.327±0.050 and 7.367±0.043, respectively, significantly better than those in control group (7.304±0.021 and 7.390±0.029, respectively, t=-2.385, 2.391, P<0.05). The PaO(2) values of patients in observation group on PID 7 and 14 were (95.1±6.7) and (106.3±7.8) mmHg (1 mmHg=0.133 kPa), respectively, significantly higher than those in control group [(91.6±5.7) and (102.0±8.3) mmHg, respectively, t=-2.109, -2.059, P<0.05]. The PaCO(2) values of patients in observation group on PID 7 and 14 were (41±4) and (40±4) mmHg, respectively, significantly lower than those in control group [(43±5) and (43±4) mmHg, respectively, t=2.220, 2.304, P<0.05]. The SaO(2) values of patients in observation group on PID 7 and 14 were 0.95±0.04 and 0.96±0.04, respectively, significantly higher than those in control group (0.93±0.05 and 0.94±0.05, respectively, t=-2.201, -2.016, P<0.05). The oxygenation indexes of patients in observation group on PID 7 and 14 were (286±18) and (329±20) mmHg, significantly higher than those in control group [(277±14) and (306±58) mmHg, respectively, t=-2.263, -2.022, P<0.05]. (2) Sputum viscosity of patients in observation group in post injury week(s) 1, 2, and 3 were superior to that in control group (Z=-2.096, -2.076, -2.033, P<0.05). (3) VAP occurrence rate of patients in observation group was lower than that in control group, and time of mechanical ventilation of patients in observation group was shorter than that in control group (χ(2)=4.244, t=2.425, P<0.05). (4) Survival rate of patients in observation group was higher than that in control group (χ(2)=4.244, P<0.05). Conclusions: The special intensive care of airway management by AMT can effectively improve the oxygenation status of severely burned patients combined with inhalation injury, alleviate the sputum viscosity, reduce the occurrence of VAP, and shorten the time of mechanical ventilation, thus benefits the treatment of severely mass burn patients combined with inhalation injury.

Vanillic acid mitigates the ovalbumin (OVA)-induced asthma in rat model through prevention of airway inflammation

Asthma is a chronic allergic ailment affecting a considerably large population of the world. The aim of this study is to evaluate the ameliorative effects of vanillic acid against ovalbumin (OVA)-induced asthma in rat model. Asthma was induced in Sprague Dawley rats and vanillic acid was orally administered at 25 and 50 mg/kg body weight for 28 days. Rats challenged with OVA showed heavy signs of airway inflammation and remodeling similar to chronic asthma, evidenced by the increased differential cell counts and presence of inflammatory cytokines in the bronchoalveolar lavage fluid (BALF), along with elevated serum immunoglobulin levels, and the histological results. However, vanillic acid dose-dependently attenuated the manifestation of OVA-induced asthma (p < 0.05) through suppression of inflammatory mediators and modulation of immunoglobulin levels in rats. The asthma mitigating properties of vanillic acid might be due to suppression of oxidative stress and prevention of lung airway inflammation.

Discovery of a Potent and Selective Steroidal Glucocorticoid Receptor Antagonist (ORIC-101)

The glucocorticoid receptor (GR) has been linked to therapy resistance across a wide range of cancer types. Preclinical data suggest that antagonists of this nuclear receptor may enhance the activity of anticancer therapy. The first-generation GR antagonist mifepristone is currently undergoing clinical evaluation in various oncology settings. Structure-based modification of mifepristone led to the discovery of ORIC-101 (28), a highly potent steroidal GR antagonist with reduced androgen receptor (AR) agonistic activity amenable for dosing in androgen receptor positive tumors and with improved CYP2C8 and CYP2C9 inhibition profile to minimize drug-drug interaction potential. Unlike mifepristone, 28 could be codosed with chemotherapeutic agents readily metabolized by CYP2C8 such as paclitaxel. Furthermore, 28 demonstrated in vivo antitumor activity by enhancing response to chemotherapy in the GR⁺ OVCAR5 ovarian cancer xenograft model. Clinical evaluation of safety and therapeutic potential of 28 is underway.

Abstract 1968: A novel glucocorticoid receptor (GR) antagonist overcomes GR-mediated chemoresistance in triple-negative breast cancer

The glucocorticoid receptor (GR) is a member of the nuclear receptor superfamily, which is activated by its endogenous steroid hormone ligand cortisol, and by synthetic glucocorticoids such as dexamethasone. Several preclinical studies have shown that GR mediates resistance to both targeted therapies and conventional chemotherapies in a variety of epithelial cancers including prostate, lung, bladder, renal, ovarian and triple-negative breast cancers (TNBC) (Gassler et al., 2005; Li et al., 2017; Zhang et al., 2007). In TNBC, both GR activation and a disrupted cortisol secretion cycle are associated with chemotherapy resistance, increased disease recurrence and poor prognosis (Pan et al., 2011; Skor et al., 2013). Therefore a molecule that inhibits GR activation could attenuate the development of therapy resistance and improve patient outcomes. We have developed novel GR inhibitors that effectively block GR transcriptional activity in cells by competing for ligand binding and by blocking GR-coactivator interactions. In vitro, treatment of TNBC cells with the GR antagonist OP-3713 blocks GR transcriptional activity and enhances the efficacy of chemotherapeutic agents. In rodents the predominant glucocorticoid is corticosterone (Siswanto et al., 2008), which is a weak agonist of human GR. Therefore, to fully activate GR in human xenograft cancer models it is necessary to provide exogenous cortisol. Using xenograft models of TNBC, we find that tumors grown in mice with physiologically relevant circulating cortisol levels to activate GR are significantly less sensitive to chemotherapy than those grown in the absence of cortisol. Furthermore, inhibition of GR by OP-3713 prevents tumor relapse following chemotherapy treatment. We have begun to elucidate the mechanisms by which GR mediates chemoresistance in TNBC, and the basis for the reversal by OP-3713. Our findings underscore the important role of GR as a mediator of resistance in TNBC and highlight the therapeutic potential of GR inhibitors in combination with clinically relevant chemotherapeutic agents.

Citation Format: Nadine Jahchan, Haiying Zhou, Wayne Kong, Dan Mc Weeney, Ted Tracy, James Stice, Dena Sutimantanapi, Chelsea Chen, Tom Huang, Yosup Rew, Xiauhui Du, Tatiana Zavorotinskaya, Daqing Sun, Qiuping Ye, Erica Jackson, Valeria Fantin. A novel glucocorticoid receptor (GR) antagonist overcomes GR-mediated chemoresistance in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1968.