Insights into Mechanisms and Promising Triple Negative Breast Cancer Therapeutic Potential for a Water-Soluble Ruthenium Compound

Triple negative breast cancer (TNBC) represents a subtype of breast cancer that does not express the three major prognostic receptors of human epidermal growth factor receptor 2 (HER2), progesterone (PR), and estrogen (ER). This limits treatment options and results in a high rate of mortality. We have reported previously on the efficacy of a water-soluble, cationic organometallic compound (Ru-IM) in a TNBC mouse xenograft model with impressive tumor reduction and targeted tumor drug accumulation. Ru-IM inhibits cancer hallmarks such as migration, angiogenesis, and invasion in TNBC cells by a mechanism that generates apoptotic cell death. Ru-IM displays little interaction with DNA and appears to act by a P53-independent pathway. We report here on the mitochondrial alterations caused by Ru-IM treatment and detail the inhibitory properties of Ru-IM in the PI3K/AKT/mTOR pathway in MDA-MB-231 cells. Lastly, we describe the results of an efficacy study of the TNBC xenografted mouse model with Ru-IM and Olaparib monotherapy and combinatory treatments. We find 59% tumor shrinkage with Ru-IM and 65% with the combination. Histopathological analysis confirmed no test-article-related toxicity. Immunohistochemical analysis indicated an inhibition of the angiogenic marker CD31 and increased levels of apoptotic cleaved caspase 3 marker, along with a slight inhibition of p-mTOR. Taken together, the effects of Ru-IM in vitro show similar trends and translation in vivo. Our investigation underscores the therapeutic potential of Ru-IM in addressing the challenges posed by TNBC as evidenced by its robust efficacy in inhibiting key cancer hallmarks, substantial tumor reduction, and minimal systemic toxicity.

Tracking the fate of bacteria-derived site-specific immunomodulators by positron emission tomography

INTRODUCTION

Site-specific immunomodulators (SSIs) are a novel class of therapeutics made from inactivated bacterial species designed to regulate the innate immune system in targeted organs. QBECO is a gut-targeted SSI that is being advanced clinically to treat and/or prevent inflammatory bowel disease, cancer, and serious infections of the gastrointestinal (GI) tract and proximal organs, and QBKPN is a lung-targeted SSI that is in clinical development for the treatment and/or prevention of chronic inflammatory lung disease, lung cancers and respiratory tract infections. While these SSIs have demonstrated both safety and proof-of-concept in preclinical and clinical studies, detailed understanding of their trafficking and biodistribution is yet to be fully characterized.

METHODS

QBECO and QBKPN were radiolabeled with [89Zr] and injected subcutaneously into healthy mice. The mice underwent Positron Emission Tomography (PET) imaging every day for eight days to track biodistribution of the SSIs. Tissue from the site of injection was collected and immunohistologically probed for immune cell infiltration.

RESULTS

Differential biodistribution of the two SSIs was seen, adhering to their site-specific targeting. QBKPN appeared to migrate from the site of injection (abdomen) to the cervical lymph nodes which are nearer to the respiratory tract and lungs. QBECO remained in the abdominal region, with lymphatic trafficking to the inguinal lymph nodes, which are nearer to GI-proximal tissues/organs. Immune infiltration at the site of injection comprised of neutrophils for both SSIs, and macrophages for only QBKPN.

CONCLUSION

Radiolabeling of SSIs allows for longitudinal in vivo imaging of biodistribution and trafficking. PET imaging revealed differential biodistribution of the SSIs based on the organotropism of the bacteria from which the SSI is derived. Trafficking from the site of injection to the targeted site is in part mediated via the lymphatics and involves macrophages and neutrophils.

The Metallodrug BOLD-100 Is a Potent Inhibitor of SARS-CoV-2 Replication and Has Broad-Acting Antiviral Activity

The COVID-19 pandemic has highlighted an urgent need to discover and test new drugs to treat patients. Metal-based drugs are known to interact with DNA and/or a variety of proteins such as enzymes and transcription factors, some of which have been shown to exhibit anticancer and antimicrobial effects. BOLD-100 (sodium trans-[tetrachlorobis(1H-indazole)ruthenate(III)]dihydrate) is a novel ruthenium-based drug currently being evaluated in a Phase 1b/2a clinical trial for the treatment of advanced gastrointestinal cancer. Given that metal-based drugs are known to exhibit antimicrobial activities, we asked if BOLD-100 exhibits antiviral activity towards SARS-CoV-2. We demonstrated that BOLD-100 potently inhibits SARS-CoV-2 replication and cytopathic effects in vitro. An RNA sequencing analysis showed that BOLD-100 inhibits virus-induced transcriptional changes in infected cells. In addition, we showed that the antiviral activity of BOLD-100 is not specific for SARS-CoV-2, but also inhibits the replication of the evolutionarily divergent viruses Human Immunodeficiency Virus type 1 and Human Adenovirus type 5. This study identifies BOLD-100 as a potentially novel broad-acting antiviral drug.

Abstract 2259: Novel metallotherapeutic BOLD-100 induces circulating cytokine changes when administered in combination with FOLFOX in advanced gastrointestinal cancer patients

Proven metallotherapeutics, such as cisplatin and oxaliplatin, alter immune responses as part of their multimodal mechanisms-of-action. These immune responses can drive efficacy in specific patient populations and/or in combination with other oncology drugs. BOLD-100, currently in a multinational Phase 2 trial, is a first-in-class metallotherapeutic that (1) alters the unfolded protein response (UPR) through selective GRP78 inhibition, and (2) induces reactive oxygen species (ROS), leading to DNA damage and cell cycle arrest. Collectively, these pathways result in cell death in both sensitive and resistant cancers, giving BOLD-100 the potential to significantly improve outcomes in a wide range of both solid and liquid tumors in combination with other anticancer therapies. BOLD-100 can also alter immune responses, including through induction of immunogenic cell death, but these responses have not been investigated in a clinical population. A recently completed Phase 1b trial investigating BOLD-100 in combination with FOLFOX demonstrated a 3X improvement in progression-free survival (PFS) in 3rd line or later metastatic colorectal cancer patients compared to existing therapies, with a favorable safety profile. In this Phase 1b study, BOLD-100 was administered via IV infusion for 60-90 minutes immediately prior to FOLFOX on a 2-week cycle. To investigate the pharmacodynamics of immune markers, plasma samples were collected at baseline and 1, 6, 24, and 48 hours after initiation of BOLD-100 plus FOLFOX treatment for each of the first 4 cycles, and then at baseline for all subsequent cycles. In 326 samples collected from 15 patients, 48 cytokines were measured via multiplex. Multiple cytokines showed short-term (1 to 48 hours) transient increases in plasma concentration levels, including IL-10, IL-27, G-CSF, MIP-1β, IP-10, IL-2, IL-18 and TNFα. IL-10, a cytokine previously investigated as an anticancer therapeutic, increased significantly by 1 hour (6.7X increase) and by 6 hours (84.5X increase) after treatment, before reverting to baseline levels by 48 hours. Despite large acute increases in specific cytokines, no changes to baseline levels over multiple treatment cycles were observed. Correlation analysis showed that baseline MCP-1 and MIP-1α levels were negatively correlated with overall survival; and the maximum change in concentration over the first dosage cycle of RANTES, IL-17F, Eotaxin, TGFα and MDC were positively correlated with overall survival. These results show that BOLD-100 in combination with FOLFOX can induce immune responses, and that these immune responses may predict clinical outcome. Analysis of additional patient samples from the Phase 2 trial is ongoing.

Citation Format: Mark Bazett, Brian Park, E Russell McAllister, Jim Pankovich. Novel metallotherapeutic BOLD-100 induces circulating cytokine changes when administered in combination with FOLFOX in advanced gastrointestinal cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2259.

Abstract 5489: Utilization of cancer cell line screening and bioinformatic analyses to identify optimal developmental pathways for the novel anticancer agent BOLD-100

Cell line screening of unique compounds can provide mechanistic insights and identify optimal drug combination partners. Bioinformatics analysis of cell screen data and correlation to publicly available datasets can support identification of appropriate patient populations for subsequent preclinical and clinical development. BOLD-100 is a first-in-class ruthenium-based anticancer agent currently being tested in a Phase 1b/2a clinical trial in combination with FOLFOX in the treatment of advanced gastrointestinal cancers. BOLD-100 works by altering the unfolded protein response through selective GRP78 inhibition; and inducing reactive oxygen species which causes DNA damage and cell cycle arrest. Collectively, these result in cell death in a range of different cancer types, and in combination with many different classes of anticancer agents. To determine optimal indications for BOLD-100 development, BOLD-100 was tested against 316 cancer cell lines in 72-hour Cell Titer Glo assays with downstream bioinformatic analysis and validation experiments. Multiple cancer types showed preferential response to BOLD-100, including bladder, esophageal, pancreatic, multiple myeloma and ovarian cancers. Subtype analysis identified potential populations of increased responsiveness, including in bladder cancer where BOLD-100 had increased response in luminal and mixed subtypes, as compared to basal subtypes. Utilizing bladder cancer as a case study, subsequent combination testing of BOLD-100 in combination with fluorouracil or cisplatin demonstrated that BOLD-100 enhanced cell death across different bladder cancer cell lines through synergistic interactions with these standard-of-care agents. The pan-cancer response profile of BOLD-100 was compared against 449 other anticancer drug responses that are part of the GDSC database. BOLD-100 displayed limited correlation with existing drugs, suggesting a unique mechanism of action and clinical utility where standard-of-care agents have limited efficacy. Pharmacogenomic analysis of the cell screen data indicated potential pathways and genes of relevance to BOLD-100 response, including increased response in KRAS-mutant cancers. Collectively, BOLD-100 showed a unique sensitivity profile across a panel of over 300 cancer cell lines, identifying multiple potential indications for future development. Subsequent investigations into several cancer types of interest and drug combinations are ongoing.

Citation Format: Paromita Raha, Brian Park, Adam Carie, Jim Pankovich, Mark Bazett. Utilization of cancer cell line screening and bioinformatic analyses to identify optimal developmental pathways for the novel anticancer agent BOLD-100 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5489.

Abstract 1183: Targeting the DNA repair pathway with BOLD-100 in BRAF mutant colorectal cancer

Background: BRAF mutations (BRAFMT) occur in ∼10-15% of metastatic colorectal cancer (mCRC) and have a poor clinical outcome, in particular those with microsatellite stable (MSS) disease. Anti-BRAF/EGFR combinations have shown some increases in response rate, but this is associated with minor increases in overall survival. There is an unmet need to understand the biology of poor prognostic BRAFMT CRC. Using publicly available gene expression data from 155 CRC cell lines (GSE59857), we recently identified that unfolded protein response (UPR) and DNA repair are dominant pathways deregulated in the consensus molecular subgroup 1/BRAFMT subgroup. The aim of this study was to investigate the role of BOLD-100, an inhibitor of the UPR regulator GRP78, in regulating the survival of CRC cells.

Methods: A panel of isogenic paired and non-isogenic V600E BRAFMT and BRAFWT cells were used. BOLD-100, a ruthenium-based small molecule inhibitor, was obtained from BOLD Therapeutics. Cell Titre Glo, Flow Cytometry, Western blotting, Caspase 8, 3/7 activity, RNAi assays were used. RNA seq and IPA bioinformatic analyses were performed on BOLD-100-treated BRAFMT/WT CRC cells. A compound library including small molecules approved by the FDA was used.

Results: In vitro CellTitre-Glo® and Annexin V/PI sensitivity studies showed that the BRAFMT, MSS CRC cells were highly sensitive to BOLD-100 with IC50 values between 9.25-31μM. Treatment with BOLD-100 resulted in early decreases in GRP78 levels and increases in expression levels of the endoplasmic reticulum stress protein CHOP, and this was associated with caspase-8 dependent cell death in the BRAFMT CRC cells. Notably, silencing of CHOP did not abrogate BOLD-100-induced cell death in BRAFMT CRC cells, indicating that the UPR pathway played no role in the cell death following BOLD-100. RNA seq and IPA analysis showed that cell cycle regulation and DNA repair were the most significant deregulated pathways following BOLD-100 treatment. Further mechanistic studies revealed that BOLD-100 induced rapid and potent increases in pATRT1989, pChk1S345 and γH2AX expression levels in BRAFMT cells. Using a small molecule compound library, we found that the ATR inhibitors AZD6783 and M4344 resulted in strong synergy and apoptosis when combined with BOLD-100, in particular in BRAFMT CRC cells. Moreover, we found that the ROS scavenger NAC abrogated BOLD-100 induced CHOP, pATRT1989, pChk1S345 and γH2AX levels and rescued cell death following BOLD-100 treatment in BRAFMT CRC cells.

Conclusions: Taken together, we have identified a role for BOLD-100 in regulating the survival of BRAFMT CRC cells. Our data support further studies with BOLD-100, in particular in combination with ATRi, for the treatment of BRAFMT CRC tumours.

Citation Format: Robbie Carson, Shivaali Karelia, Deborah Lavin, Vijay Tiwari, Richard Kennedy, Kienan Savage, Adam Carie, Jim Pankovich, Mark Bazett, Sandra Van Schaeybroeck. Targeting the DNA repair pathway with BOLD-100 in BRAF mutant colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1183.

Novel Microbial-Based Immunotherapy Approach for Crohn's Disease

Background: Current Crohn's disease (CD) therapies focus on suppressing immune function and come with consequent risk, such as infection and cancer. Notwithstanding, most CD patients still experience disease progression. There is a need for new CD treatment strategies that offer better health outcomes for patients.

Aims: To assess safety, efficacy, and tolerability of a novel microbial-derived immunotherapy, QBECO, that aims to restore rather than suppress immune function in CD.

Methods: A randomized, double-blind, placebo-controlled trial was conducted in 68 patients with moderate-to-severe CD. Primary endpoints: safety and Week 8 clinical improvement. Secondary endpoints: Week 8 clinical response and remission. Week 8 responders continued blinded treatment through Week 16; non-responders received open-label QBECO from Weeks 9–16. Exploratory analyses included immune biomarker and genotype assessments.

Results: QBECO was well-tolerated. Mean reduction in Crohn's Disease Activity Index (CDAI) score was −68 for QBECO vs. −31 for placebo at Week 8. Improvement with QBECO continued through Week 16 (-130 CDAI reduction). Week 8 QBECO clinical response, improvement and remission rates were 41.2%, 32.4%, 29.4% vs. 26.5%, 23.5%, 23.5% for placebo. TNFα inhibitor-naïve subjects achieved higher response rates at Week 8 with QBECO (64%) vs. placebo (26%). Specific immune biomarkers were identified that linked to QBECO response.

Conclusion: This proof-of-concept study supports further investigation for the use of QBECO as a novel immunotherapy approach for CD. Biomarker analyses suggests it may be feasible to personalize CD treatment with QBECO. Larger trials are now needed to confirm clinical improvement and the unique biological findings.

Clinical Trial Number: NCT01809275 (https://clinicaltrials.gov/ct2/show/NCT01809275)

STAT6 inhibitory peptide reduces dendritic cell migration to the lymph nodes to control Th2 adaptive immunity in the mouse lung

Type 2 immunity in the lung is promoted through the release of innate cytokines, including TSLP, from lung structural cells. These cytokines drive Type 2 immunity in part through upregulation of OX40L on dendritic cells (DCs). DCs expressing OX40L are potent inducers of Th2 differentiation. We have shown previously that STAT6 inhibitory peptide (STAT6-IP), a cell penetrating peptide designed to inhibit the STAT6 transcription factor, reduces the induction of Th2 adaptive immunity in murine models of respiratory syncytial virus infection. Here we show that intranasal administration of STAT6-IP at the time of antigen priming with ovalbumin (OVA), in conjunction with the Nod2 agonist, MDP, reduced frequencies of CD11b⁺ lung DCs expressing OX40L. Consistent with these reductions, fewer activated DCs were localized to the lung draining lymph nodes in STAT6-IP-treated mice. Upon OVA challenge four weeks later, mice treated with STAT6-IP at the time of OVA/MDP priming did not develop airway hyperresponsiveness (AHR) and had reduced influx of eosinophils into the airways, mucus production, and serum OVA-specific IgE levels. Our findings provide evidence that the long-lasting inhibitory effects of STAT6-IP are due in part to inhibition of DC responses that drive maladaptive Th2 adaptive immunity and allergic airways disease.

Immune Stimulation Using a Gut Microbe-Based Immunotherapy Reduces Disease Pathology and Improves Barrier Function in Ulcerative Colitis

Background: Current ulcerative colitis (UC) treatments are focused on symptom management primarily via immune suppression. Despite the current arsenal of immunosuppressant treatments, the majority of patients with UC still experience disease progression. Importantly, aggressive long-term inhibition of immune function comes with consequent risk, such as serious infections and malignancy. There is thus a recognized need for new, safe and effective treatment strategies for people living with UC that work upstream of managing the symptoms of the disease. The objective of this study was to evaluate a microbial-based treatment, QBECO, that functions to productively activate rather than suppress mucosal immune function as a novel approach to treat UC. Methods: Two established models of experimental colitis, namely chemically-induced DSS colitis and the spontaneous colitis that develops in Muc2 deficient mice, were used to assess whether QBECO treatment could ameliorate gastrointestinal disease. A small exploratory 16-week QBECO open-label trial was subsequently conducted to test the safety and tolerability of this approach and also to determine whether similar improvements in clinical disease and histopathology could be demonstrated in patients with moderate-to-severe UC. Results: QBECO treatment successfully reduced inflammation and promoted mucosal and histological healing in both experimental models and in UC patients. The preclinical models of colitis showed that QBECO ameliorated mucosal pathology, in part by reducing inflammatory cell infiltration, primarily that induced by neutrophils and inflammatory T cells. The most rapid and noticeable change observed in QBECO treated UC patients was a marked reduction in rectal bleeding. Conclusion: Collectively, this work demonstrates for the first time that strategically activating immune function rather than suppressing it, not only does not worsen colitis induced-damage, but may lead to an objective reduction in UC disease pathology.

Harnessing innate lung anti-cancer effector functions with a novel bacterial-derived immunotherapy

Acute infection is known to induce strong anti-tumor immune responses, but clinical translation has been hindered by the lack of an effective strategy to safely and consistently provoke a therapeutic response. These limitations are overcome with a novel treatment approach involving repeated subcutaneous delivery of a Klebsiella-derived investigational immunotherapeutic, QBKPN. In preclinical models of lung cancer, QBKPN administration consistently showed anti-cancer efficacy, which was dependent on Klebsiella pre-exposure, but was independent of adaptive immunity. Rather, QBKPN induced anti-tumor innate immunity that required NK cells and NKG2D engagement. QBKPN increased NK cells and macrophages in the lungs, altered macrophage polarization, and augmented the production of cytotoxic molecules. An exploratory trial in patients with non-small cell lung cancer demonstrated QBKPN was well tolerated, safe, and induced peripheral immune changes suggestive of macrophage polarization and reduction of PD-1 and PD-L1 expression on leukocytes. These data demonstrate preclinical efficacy, and clinical safety and tolerability, for this cancer immunotherapy strategy that exploits innate anti-tumor immune mechanisms.

Attenuating immune pathology using a microbial-based intervention in a mouse model of cigarette smoke-induced lung inflammation

Background

Cigarette smoke exposure is the major risk factor for developing COPD. Presently, available COPD treatments focus on suppressing inflammation and providing bronchodilation. However, these options have varying efficacy in controlling symptoms and do not reverse or limit the progression of COPD. Treatments strategies using bacterial-derived products have shown promise in diseases characterized by inflammation and immune dysfunction. This study investigated for the first time whether a novel immunotherapy produced from inactivated Klebsiella (hereafter referred to as KB) containing all the major Klebsiella macromolecules, could attenuate cigarette smoke exposure-induced immune responses. We hypothesized that KB, by re-directing damaging immune responses, would attenuate cigarette smoke-induced lung inflammation and bronchoalveolar (BAL) cytokine and chemokine production.

Methods

KB was administered via a subcutaneous injection prophylactically before initiating a 3-week acute nose-only cigarette smoke exposure protocol. Control mice received placebo injection and room air. Total BAL and differential cell numbers were enumerated. BAL and serum were analysed for 31 cytokines, chemokines, and growth factors. Lung tissue and blood were analysed for Ly6C^HI monocytes/macrophages and neutrophils. Body weight and clinical scores were recorded throughout the experiment.

Results

We demonstrate that KB treatment attenuated cigarette smoke-induced lung inflammation as shown by reductions in levels of BAL IFNγ, CXCL9, CXCL10, CCL5, IL-6, G-CSF, and IL-17. KB additionally attenuated the quantity of BAL lymphocytes and macrophages. In parallel to the attenuation of lung inflammation, KB induced a systemic immune activation with increases in Ly6C^HI monocytes/macrophages and neutrophils.

Conclusions

This is the first demonstration that subcutaneous administration of a microbial-based immunotherapy can attenuate cigarette smoke-induced lung inflammation, and modulate BAL lymphocyte and macrophage levels, while inducing a systemic immune activation and mobilization. These data provide a foundation for future studies exploring how KB may be used to either reverse or prevent progression of established emphysema and small airways disease associated with chronic cigarette smoke exposure. The data suggest the intriguing possibility that KB, which stimulates rather than suppresses systemic immune responses, might be a novel means by which the course of COPD pathogenesis may be altered.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-017-0577-y) contains supplementary material, which is available to authorized users.

Harnessing innate anti-tumour immunity using a Klebsiella-derived therapeutic to reduce tumour burden and improve outcomes in mouse models of lung cancer

Tumour regression and increased survival has been associated with certain acute microbial infections. Immune dysfunction contributes to the development and progression of lung cancer, and therapies that re-constitute anti-tumor immune responses provide an important means to effectively treat malignancies and improve health outcomes. We hypothesized that stimulating the innate immune system with bacterial-derived immunomodulators could induce protective anti-cancer immune responses. A Klebsiella-derived drug product, QBKPN (Qu Biologics), was used to specifically stimulate the innate immune niche in the lungs in established mouse models of lung cancer. Repeated subcutaneous administration with QBKPN significantly reduced lung tumor burden and increased survival. The protective action of QBKPN required prior exposure to Klebsiella through either environmental exposure or lung infection. However, this QBKPN-mediated anti-tumour response was independent of adaptive immunity, as the protective effect remained in RAG2-knockout mice. QBKPN intervention was characterized by a rapid, acute-like systemic immune response, including increased circulatory inflammatory cytokines and innate immune cells, leading to recruitment of immune effector cells into the lung tissue, including macrophages and natural killer (NK) cells. In addition to recruitment of innate immune cells, QBKPN increased markers of classically activated macrophages and increased production of NK cell effector molecules. Together, these data suggest that QBKPN, a Klebsiella-derived immunomodulator, causes activation and recruitment of macrophages and NK cells into the lungs, reducing cancer tumour burden and improving survival outcomes.

A novel microbe-based treatment that attenuates the inflammatory profile in a mouse model of allergic airway disease

There is an unmet need for effective new and innovative treatments for asthma. It is becoming increasingly evident that bacterial stimulation can have beneficial effects at attenuating allergic airway disease through immune modulation. Our aim was to test the ability of a novel inactivated microbe-derived therapeutic based on Klebsiella (KB) in a model of allergic airway disease in mice. BALB/c mice were exposed intranasally to house dust mite (HDM) for two weeks. Mice were treated prophylactically via subcutaneous route with either KB or placebo for one week prior to HDM exposure and throughout the two week exposure period. 24 hours after the last exposure, lungs were analysed for inflammatory cell infiltrate, gene expression, cytokine levels, goblet cell metaplasia, and serum was analysed for allergen-specific serum IgE levels. HDM exposed mice developed goblet cell hyperplasia, elevated allergen-specific serum IgE, airway eosinophilia, and a concomitant increase in T_H2 cytokines including IL-4, IL-13 and IL-5. Treatment with KB attenuated HDM-mediated airway eosinophilia, total bronchoalveolar lavage (BAL) cell numbers, BAL T_H2 cytokine production, and goblet cell metaplasia. Our prophylactic intervention study illustrates the potential of subcutaneous treatment with bacterial derived biologics as a promising approach for allergic airway disease treatment.

Site-Specific Immunomodulators (SSIs) are novel immunotherapies for cancer

The immune system recognizes and eliminates malignant cells, and maintains an intricate balance between immune activation and cancer. Historically, spontaneous tumor regression has been observed in some patients experiencing acute microbial infections. Building upon this, it was discovered that repeated subcutaneous injection of novel immunotherapies called Site-Specific Immunomodulators (SSIs), derived from killed bacteria known to cause infection in a particular organ or tissue, may be effective at treating cancer growing in the same site. We hypothesize that SSIs stimulate the body’s immune system to reverse immune suppression and dysfunction in the tumor microenvironment, enabling effective anti-cancer immune responses. To test this hypothesis, we evaluated the efficacy of a lung-specific SSI, QBKPN, in preclinical lung cancer models. Repeated subcutaneous administration of QBKPN significantly reduced lung tumor burden at day 16 post-inoculation (p<0.0001) in the Lewis Lung Carcinoma model, improving median survival by 10 days (p<0.005). Similar results were obtained using the aggressive and poorly-immunogenic B16 lung cancer model. Anticancer efficacy was associated with site-specific infiltration of newly recruited monocytes and neutrophils to the lung and mobilization of antigen presenting cells in the lung-draining lymph node. These data complement the positive results from our compassionate use clinical data, and provide strong evidence that SSIs may improve therapeutic outcomes for cancer patients. QBKPN is currently studied in a Phase 2a clinical trial of non-small cell lung cancer in collaboration with the BC Cancer Agency (Trial NCT02256852).

Cystic fibrosis mouse model-dependent intestinal structure and gut microbiome

Mice with a null mutation in the cystic fibrosis transmembrane conductance regulator (Cftr) gene show intestinal structure alterations and bacterial overgrowth. To determine whether these changes are model-dependent and whether the intestinal microbiome is altered in cystic fibrosis (CF) mouse models, we characterized the ileal tissue and intestinal microbiome of mice with the clinically common ΔF508 Cftr mutation (FVB/N Cftr(tm1Eur)) and with Cftr null mutations (BALB/c Cftr(tm1UNC) and C57BL/6 Cftr(tm1UNC)). Intestinal disease in 12-week-old CF mice, relative to wild-type strain controls, was measured histologically. The microbiome was characterized by pyrosequencing of the V4-V6 region of the 16S rRNA gene and intestinal load was measured by RT-PCR of the 16S rRNA gene. The CF-associated increases in ileal crypt to villus axis distention, goblet cell hyperplasia, and muscularis externa thickness were more severe in the BALB/c and C57BL/6 Cftr(tm1UNC) mice than in the FVB/N Cftr(tm1Eur) mice. Intestinal bacterial load was significantly increased in all CF models, compared to levels in controls, and positively correlated with circular muscle thickness in CF, but not wild-type, mice. Microbiome profiling identified Bifidobacterium and groups of Lactobacillus to be of altered abundance in the CF mice but overall bacterial frequencies were not common to the three CF strains and were not correlative of major histological changes. In conclusion, intestinal structure alterations, bacterial overgrowth, and dysbiosis were each more severe in BALB/c and C57BL/6 Cftr(tm1UNC) mice than in the FVB/N Cftr(tm1Eur) mice. The intestinal microbiome differed among the three CF mouse models.

Airway hyperresponsiveness in FVB/N delta F508 cystic fibrosis transmembrane conductance regulator mice

BACKGROUND

Airway hyperresponsiveness is a feature of clinical CF lung disease. In this study, we investigated whether the FVB/N ΔF508 CFTR mouse model has altered airway mechanics.

METHODS

Mechanics were measured in 12-14week old FVB/N Cftr(tm1Eur) (ΔF508) mice and wildtype littermates using the FlexiVent small animal ventilator. Lung disease was assayed by immunohistochemistry, histology and bronchoalveolar lavage analysis.

RESULTS

Cftr(tm1Eur) mice presented with increased airway resistance, compared to wildtype littermates, in response to methacholine challenge. No differences in bronchoalveolar cell number or differential, or in tissue lymphocyte, goblet cell or smooth muscle actin levels were evident in mice grouped by Cftr genotype. The bronchoalveolar lavage of Cftr(tm1Eur) mice included significantly increased levels of interleukin 12(p40) and CXCL1 compared to controls.

CONCLUSION

We conclude that the pulmonary phenotype of Cftr(tm1Eur) mice includes airway hyperresponsiveness in the absence of overt lung inflammation or airway remodeling.

Strain-dependent airway hyperresponsiveness and a chromosome 7 locus of elevated lymphocyte numbers in cystic fibrosis transmembrane conductance regulator-deficient mice

We previously observed the lungs of naive BALB/cJ Cftr(tm1UNC) mice to have greater numbers of lymphocytes, by immunohistochemical staining, than did BALB wild type littermates or C57BL/6J Cftr(tm1UNC) mice. In the present study, we initially investigated whether this mutation in Cftr alters the adaptive immunity phenotype by measuring the lymphocyte populations in the lungs and spleens by FACS and by evaluating CD3-stimulated cytokine secretion, proliferation, and apoptosis responses. Next, we assessed a potential influence of this lymphocyte phenotype on lung function through airway resistance measures. Finally, we mapped the phenotype of pulmonary lymphocyte counts in BALB × C57BL/6J F2 Cftr(tm1UNC) mice and reviewed positional candidate genes. By FACS analysis, both the lungs and spleens of BALB Cftr(tm1UNC) mice had more CD3(+) (both CD4(+) and CD8(+)) cells than did littermates or C57BL/6J Cftr(tm1UNC) mice. Cftr(tm1UNC) and littermate mice of either strain did not differ in anti-CD3-stimulated apoptosis or proliferation levels. Lymphocytes from BALB Cftr(tm1UNC) mice produced more IL-4 and IL-5 and reduced levels of IFN-γ than did littermates, whereas lymphocytes from C57BL/6J Cftr(tm1UNC) mice demonstrated increased Il-17 secretion. BALB Cftr(tm1UNC) mice presented an enhanced airway hyperresponsiveness to methacholine challenge compared with littermates and C57BL/6J Cftr(tm1UNC) mice. A chromosome 7 locus was identified to be linked to lymphocyte numbers, and genetic evaluation of the interval suggests Itgal and Il4ra as candidate genes for this trait. We conclude that the pulmonary phenotype of BALB Cftr(tm1UNC) mice includes airway hyperresponsiveness and increased lymphocyte numbers, with the latter trait being influenced by a chromosome 7 locus.

MicroRNA profiling of cystic fibrosis intestinal disease in mice

Cystic fibrosis (CF) intestinal disease is characterized by alterations in processes such as proliferation and apoptosis which are known to be regulated in part by microRNAs. Herein, we completed microRNA expression profiling of the intestinal tissue from the cystic fibrosis mouse model of cystic fibrosis transmembrane conductance regulator (Cftr) deficient mice (BALBc/J Cftr(tm1UNC)), relative to that of wildtype littermates, to determine whether changes in microRNA expression level are part of this phenotype. We identified 24 microRNAs to be significantly differentially expressed in tissue from CF mice compared to wildtype, with the higher expression in tissue from CF mice. These data were confirmed with real time PCR measurements. A comparison of the list of genes previously reported to have decreased expression in the BALB×C57BL/6J F2 CF intestine to that of genes putatively targeted by the 24 microRNAs, determined from target prediction software, revealed 155 of the 759 genes of the expression profile (20.4%) to overlap with predicted targets, which is significantly more than the 100 genes expected by chance (p=1×10(-8)). Pathway analysis identified these common genes to function in phosphatase and tensin homolog-, protein kinase A-, phosphoinositide-3 kinase/Akt- and peroxisome proliferator-activated receptor alpha/retinoid X receptor alpha signaling pathways, among others, and through real time PCR experiments genes of these pathways were demonstrated to have lower expression in the BALB CF intestine. We conclude that altered microRNA expression is a feature which putatively influences both metabolic abnormalities and the altered tissue homeostasis component of CF intestinal disease.