Analysis of the Microbiome of the Ear Canal in Normal Individuals and Patients with Chronic Otitis Externa

BACKGROUND

Recently, microbiome research has been actively conducted for various skin areas. However, no study has yet compared the microbiome of bacteria and fungi in the ear canal of healthy individuals and patients with chronic otitis externa in Korea.

OBJECTIVE

This study aimed to investigate the difference in the distribution of fungal and bacterial microbial communities in ear canal samples of healthy individuals and patients with chronic otitis externa.

METHODS

In 24 patients with bilateral chronic otitis externa and 24 healthy controls, cotton swabs were used to obtain samples from the bilateral ear canal. To characterize the fungal and bacterial communities, we sequenced and analyzed the 16S rRNA V4-V5 and ITS1 regions using Quantitative Insights into Microbial Ecology 2, respectively.

RESULTS

The alpha diversity analysis for bacteria and fungi confirmed that both richness and evenness decreased in the patient group. The beta diversity analysis for bacteria confirmed that these parameters differed between the control and patient groups. The beta diversity analysis for fungi showed no difference between the groups.

CONCLUSION

We observed different skin microbiomes in the patients with chronic otitis externa compared with those in the healthy individuals.

Dynamic alterations in PD-1/PD-L1 expression level and immune cell profiles based on radiation response status in mouse tumor model

Introduction

Based on the immunologic effects of anti-cancer treatment and their therapeutic implications, we evaluated radiotherapy (RT)-induced dynamic alterations in programmed death-1 (PD-1)/PD ligand-1 (PD-L1) expression profiles.

Methods

Local RT with 2 Gy × 5 or 7.5 Gy × 1 was administered to the CT26 mouse model. Thereafter, tumors were resected and evaluated at the following predefined timepoints according to radiation response status: baseline, early (immediately after RT), middle (beginning of tumor shrinkage), late (stable status with RT effect), and progression (tumor regrowth). PD-1/PD-L1 activity and related immune cell profiles were quantitatively assessed.

Results

RT upregulated PD-L1 expression in tumor cells from the middle to late phase; however, the levels subsequently decreased to levels comparable to baseline in the progression phase. RT with 2 Gy × 5 induced a higher frequency of PD-L1+ myeloid-derived suppressor cells, with a lesser degree of tumor regression, compared to 7.5 Gy. The proportion of PD-1+ and interferon (IFN)-γ+CD8α T cells continued to increase. The frequency of splenic PD-1+CD8+ T cells was markedly elevated, and was sustained longer with 2 Gy × 5. Based on the transcriptomic data, RT stimulated the transcription of immune-related genes, leading to sequentially altered patterns.

Discussion

The dynamic alterations in PD-1/PD-L1 expression level were observed according to the time phases of tumor regression. This study suggests the influence of tumor cell killing and radiation dosing strategy on the tumor immune microenvironment.

PI3Kδ/γ inhibitor BR101801 extrinsically potentiates effector CD8+ T cell-dependent antitumor immunity and abscopal effect after local irradiation

BACKGROUND

Radiotherapy enhances antitumor immunity. However, it also induces immunosuppressive responses, which are major hurdles for an effective treatment. Thus, targeting the immunosuppressive tumor microenvironment is essential for enhancing the antitumor immunity after radiotherapy. Retrospective studies show that a blockade of PI3Kδ and/or γ, which are abundant in leukocytes, exhibits antitumor immune response by attenuating activity of immune suppressive cells, however, the single blockade of PI3Kδ or γ is not sufficient to completely eliminate solid tumor.

METHODS

We used BR101801, PI3Kδ/γ inhibitor in the CT-26 syngeneic mouse model with a subcutaneously implanted tumor. BR101801 was administered daily, and the target tumor site was locally irradiated. We monitored the tumor growth regularly and evaluated the immunological changes using flow cytometry, ELISpot, and transcriptional analysis.

RESULTS

This study showed that BR101801 combined with irradiation promotes systemic antitumor immunity and abscopal response by attenuating the activity of immune suppressive cells in the CT-26 tumor model. BR101801 combined with irradiation systemically reduced the proliferation of regulatory T cells (Tregs) and enhanced the number of tumor-specific CD8α⁺ T cells in the tumor microenvironment, thereby leading to tumor regression. Furthermore, the high ratio of CD8α⁺ T cells to Tregs was maintained for 14 days after irradiation, resulting in remote tumor regression in metastatic lesions, the so-called abscopal effect. Moreover, our transcriptomic analysis showed that BR101801 combined with irradiation promoted the immune-stimulatory tumor microenvironment, suggesting that the combined therapy converts immunologically cold tumors into hot one.

CONCLUSIONS

Our data suggest the first evidence that PI3Kδ/γ inhibition combined with irradiation promotes systemic antitumor immunity against solid tumors, providing the preclinical result of the potential use of PI3Kδ/γ inhibitor as an immune-regulatory radiosensitizer.

600 BR101801 stimulates anti-tumor immunity and enhances the efficacy of radiation in a syngeneic model

Background

BR101801 is an inhibitor of PI3K γ/δ and DNA-PK. It has received clinical approval from the U.S. FDA as an anticancer drug candidate, and phase 1a/1b is ongoing in the U.S. and South Korea. According to the prior studies PI3K γ/δ inhibition exhibits anticancer immune effects by changing the tumor microenvironment [1]. In addition, ionizing radiation (IR) activates the immune response by causing the destroyed cells to act as antigens [2]. Therefore, the combination of BR101801 and IR can induce cancer cell death and amplify anticancer immune effects. This study aims to demonstrate efficacy of the BR101801 as a potent cancer immunotherapy.

Methods

The enzymatic potency of PI3K isotype and DNA-PK was analyzed by Eurofins. The effects of BR101801 on cell viability were evaluated in 4T1 (breast cancer) and CT-26 (colon cancer) cells for 72 h using WST-8 assay. For in vivo studies, the tumor (4T1 or CT-26)-bearing syngeneic mice were treated with BR101801. To evaluate the synergistic effect, CT-26 tumor-bearing syngeneic mice were treated with vehicle, BR101801, IR (2 Gy or 7.5 Gy), and BR101801 + IR. Immune cells from the spleen or tumor were quantified by flow cytometry.

Results

In vitro selectivity and target potency of BR101801 on different PI3K isotypes and DNA-PK were studied in a cell-free system. The biochemical IC50 values of BR101801 for PI3K -γ, -δ, and DNA-PK were 15 nM, 2 nM, and 6 nM, respectively. In vitro 50% of maximal inhibition of cell proliferation (GI50) in 4T1 and CT26 cell lines were both above 10 μM. In 4T1 and CT-26 syngeneic models, BR101801 showed the highest tumor inhibitor efficacy (Figure 1). In particular, regulatory T cells (Tregs) & Myeloid derived suppressor cells (MDSC) were decreased and CD8+ T cells were increased in the spleens isolated from the tumor-bearing mice. Compared with other PI3K inhibitors, BR101801 had the highest efficacy, confirming that it changes the immune microenvironment. Moreover, BR101801 was synergistic in combination with 2 Gy or 7.5 Gy of IR in the syngeneic model. Notably, Tregs & Macrophage2 were decreased and CD8+ T cells were increased in the tumor tissue, confirming that the anticancer efficacy.

Abstract 600 Figure 1

Synergistic effect with ionizing radiation In Vivo

The combination of BR101801 and ionising radiation showed synergistic effects in the CT-26 Syngeneic model. BR101801 increases anti-cancer immune cells, CD8 + T cells, and decreases immune suppressor cells Tregs and macrophages through a combination of radiation, resulting in immuno-cancer effects.

Conclusions

BR101801 demonstrated an anticancer immune effect by changing the tumor microenvironment and showed synergistic effects with radiation combination therapy. We will confirm the anticancer immunity effect in ongoing clinical trials.

References

Okkenhaug K, Graupera M, Vanhaesebroeck B. Targeting PI3K in Cancer: Impact on Tumor Cells, Their Protective Stroma, Angiogenesis, and Immunotherapy. Cancer Discov. 2016; 10: 1090–1105.

McKelvey K, Hudson A, Back M, Eade T, Diakos C. Radiation, inflammation and the immune response in cancer. Mammalian Genome. 2018;9:843–865

Ethics Approval

The protocol and any amendment(s) or procedures involving the care and use of animals in this study were reviewed and approved by the Institutional animal Car and Use Committee (IACUC) of BoRyung Pharm. prior to conduct.[Approval number:BR18130]

MKI-1, a Novel Small-Molecule Inhibitor of MASTL, Exerts Antitumor and Radiosensitizer Activities Through PP2A Activation in Breast Cancer

Although MASTL (microtubule-associated serine/threonine kinase-like) is an attractive target for anticancer treatment, MASTL inhibitors with antitumor activity have not yet been reported. In this study, we have presented a novel MASTL inhibitor, MKI-1, identified through in silico screening and in vitro analysis. Our data revealed that MKI-1 exerted antitumor and radiosensitizer activities in in vitro and in vivo models of breast cancer. The mechanism of action of MKI-1 occurred through an increase in PP2A activity, which subsequently decreased the c-Myc protein content in breast cancer cells. Moreover, the activity of MKI-1 in the regulation of MASTL-PP2A was validated in a mouse oocyte model. Our results have demonstrated a new small-molecule inhibitor of MASTL, MKI-1, which exerts antitumor and radiosensitizer activities through PP2A activation in breast cancer in vitro and in vivo.

Barium Titanate Nanoparticles Sensitise Treatment-Resistant Breast Cancer Cells to the Antitumor Action of Tumour-Treating Fields

Although tumour-treating fields (TTFields) is a promising physical treatment modality based on disruption of dipole alignments and generation of dielectrophoretic forces during cytokinesis, not much is known about TTFields-responsive sensitisers. Here, we report a novel TTFields-responsive sensitiser, barium titanate nanoparticles (BTNPs), which exhibit cytocompatibility, with non-cytotoxic effects on breast cancer cells. BTNPs are characterised by high dielectric constant values and ferroelectric properties. Notably, we found that BTNPs sensitised TTFields-resistant breast cancer cells in response to TTFields. In addition, BTNPs accumulated in the cytoplasm of cancer cells in response to TTFields. Further, we showed that TTFields combined with BTNPs exhibited antitumor activity by modulating several cancer-related pathways in general, and the cell cycle-related apoptosis pathway in particular. Therefore, our data suggest that BTNPs increase the antitumor action of TTFields by an electric field-responsive cytosolic accumulation, establishing BTNP as a TTFields-responsive sensitiser.

Acquisition of Carbapenemase-Producing Enterobacteriaceae in Solid Organ Transplantation Recipients

BACKGROUND

Carbapenemase-producing Enterobacteriaceae (CPE) can lead to life-threatening outcomes with rapid spread of the carbapenemase gene in solid organ transplantation (SOT) recipients because of limitations of available antibiotics. We examined the characteristics and importance of CPE acquisition in SOT recipients with large numbers of CPE isolates.

METHODS

Between November 2015 and October 2016, 584 CPE isolates were found in 37 recipients and verified by carbapenemase gene multiplex polymerase chain reaction (PCR). One hundred recipients with at least 2 negative results in carbapenemase PCR for stool surveillance and no CPE isolates in clinical samples were retrospectively included.

RESULTS

Most CPE isolates were Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae (546, 93.5%). The most frequent transplantation organ was lung (43.3%), and the most common sample with CPE isolates other than stool was respiratory tract (22.6%). The median time between SOT and first CPE acquisition was 7 days. All-cause mortality was significantly higher in recipients with CPE than in those without CPE (24.3% vs 10.0%; P = .03). In multivariate regression analysis, stool colonization of vancomycin-resistant Enterococci and/or Clostridium difficile during 30 days before SOT (odds ratio [OR], 3.28; 95% CI, 1.24-8.68; P = .02), lung transplantation (OR, 4.50; 95% CI, 1.19-17.03; P = .03), and intensive care unit stay ≥2 weeks (OR, 6.21; 95% CI, 1.72-22.45; P = .005) were associated with acquisition of CPE.

CONCLUSIONS

Early posttransplantation CPE acquisition may affect the clinical outcome of SOT recipients. Careful screening for CPE during the early posttransplantation period would be meaningful in recipients with risk factors.

MASTL inhibition promotes mitotic catastrophe through PP2A activation to inhibit cancer growth and radioresistance in breast cancer cells

BACKGROUND

Although MASTL (microtubule-associated serine/threonine kinase-like) is a key mitotic kinase that regulates mitotic progression through the inactivation of tumor suppressor protein phosphatase 2A (PP2A), the antitumor mechanism of MASTL targeting in cancer cells is still unclear.

METHODS

MASTL expression was evaluated by using breast cancer tissue microarrays and public cancer databases. The effects of MASTL depletion with siRNAs were evaluated in various breast cancer cells or normal cells. Various methods, including cell viability, cell cycle, soft agar, immunoblotting, immunofluorescence, PP2A activity, live image, and sphere forming assay, were used in this study.

RESULTS

This study showed the oncosuppressive mechanism of MASTL targeting that promotes mitotic catastrophe through PP2A activation selectively in breast cancer cells. MASTL expression was closely associated with tumor progression and poor prognosis in breast cancer. The depletion of MASTL reduced the oncogenic properties of breast cancer cells with high MASTL expression, but did not affect the viability of non-transformed normal cells with low MASTL expression. With regard to the underlying mechanism, we found that MASTL inhibition caused mitotic catastrophe through PP2A activation in breast cancer cells. Furthermore, MASTL depletion enhanced the radiosensitivity of breast cancer cells with increased PP2A activity. Notably, MASTL depletion dramatically reduced the formation of radioresistant breast cancer stem cells in response to irradiation.

CONCLUSION

Our data suggested that MASTL inhibition promoted mitotic catastrophe through PP2A activation, which led to the inhibition of cancer cell growth and a reversal of radioresistance in breast cancer cells.

Breast cancer stem cells in HER2-negative breast cancer cells contribute to HER2-mediated radioresistance and molecular subtype conversion: clinical implications for serum HER2 in recurrent HER2-negative breast cancer

Although it has been proposed that the beneficial effect of HER2-targeted therapy in HER2-negative breast cancer is associated with the molecular subtype conversion, the underlying mechanism and the clinical biomarkers are unclear. Our study showed that breast cancer stem cells (BCSCs) mediated HER2 subtype conversion and radioresistance in HER2-negative breast cancer cells and evaluated serum HER2 as a clinical biomarker for HER2 subtype conversion. We found that the CD44⁺/CD24^–/low BCSCs from HER2-negative breast cancer MCF7 cells overexpressed HER2 and EGFR and showed the radioresistant phenotype. In addition, we showed that trastuzumab treatment sensitized the radioresistant phenotype of the CD44⁺/CD24^–/low cells with decreased levels of HER2 and EGFR, which suggested that HER2-targeted therapy in HER2-negative breast cancer could be useful for targeting BCSCs that overexpress HER2/EGFR. Importantly, our clinical data showed that serial serum HER2 measurement synchronously reflected the disease relapse and the change in tumor burden in some patients who were initially diagnosed as HER2-negative breast cancer, which indicated that serum HER2 could be a clinical biomarker for the evaluation of HER2 subtype conversion in patients with recurrent HER2-negative breast cancer. Therefore, our data have provided in vitro and in vivo evidence for the molecular subtype conversion of HER2-negative breast cancer.

Antihelminthic drug niclosamide inhibits CIP2A and reactivates tumor suppressor protein phosphatase 2A in non-small cell lung cancer cells

Protein phosphatase 2A (PP2A) is a critical tumor suppressor complex responsible for the inactivation of various oncogenes. Recently, PP2A reactivation has emerged asan anticancer strategy. Cancerous inhibitor of protein phosphatase 2A (CIP2A), an endogenous inhibitor of PP2A, is upregulated in many cancer cells, including non-small cell lung cancer (NSCLC) cells. We demonstrated that the antihelminthic drug niclosamide inhibited the expression of CIP2A and reactivated the tumor suppressor PP2A in NSCLC cells. We performed a drug-repurposing screen and identified niclosamide asa CIP2A suppressor in NSCLC cells. Niclosamide inhibited cell proliferation, colony formation, and tumor sphere formation, and induced mitochondrial dysfunction through increased mitochondrial ROS production in NSCLC cells; however, these effects were rescued by CIP2A overexpression, which indicated that the antitumor activity of niclosamide was dependent on CIP2A. We found that niclosamide increased PP2A activity through CIP2A inhibition, which reduced the phosphorylation of several oncogenic proteins. Moreover, we found that a niclosamide analog inhibited CIP2A expression and increased PP2A activity in several types of NSCLC cells. Finally, we showed that other well-known PP2A activators, including forskolin and FTY720, did not inhibit CIP2A and that their activities were not dependent on CIP2A. Collectively, our data suggested that niclosamide effectively suppressed CIP2A expression and subsequently activated PP2A in NSCLC cells. This provided strong evidence for the potential use of niclosamide asa PP2A-activating drug in the clinical treatment of NSCLC.

Consistent inhibition of cyclooxygenase drives macrophages towards the inflammatory phenotype

Macrophages play important roles in defense against infection, as well as in homeostasis maintenance. Thus alterations of macrophage function can have unexpected pathological results. Cyclooxygenase (COX) inhibitors are widely used to relieve pain, but the effects of long-term usage on macrophage function remain to be elucidated. Using bone marrow-derived macrophage culture and long-term COX inhibitor treatments in BALB/c mice and zebrafish, we showed that chronic COX inhibition drives macrophages into an inflammatory state. Macrophages differentiated in the presence of SC-560 (COX-1 inhibitor), NS-398 (COX-2 inhibitor) or indomethacin (COX-1/2 inhibitor) for 7 days produced more TNFα or IL-12p70 with enhanced p65/IκB phosphoylation. YmI and IRF4 expression was reduced significantly, indicative of a more inflammatory phenotype. We further observed that indomethacin or NS-398 delivery accelerated zebrafish death rates during LPS induced sepsis. When COX inhibitors were released over 30 days from an osmotic pump implant in mice, macrophages from peritoneal cavities and adipose tissue produced more TNFα in both the basal state and under LPS stimulation. Consequently, indomethacin-exposed mice showed accelerated systemic inflammation after LPS injection. Our findings suggest that macrophages exhibit a more inflammatory phenotype when COX activities are chronically inhibited.