ENOX2 inhibition enhances infiltration of effector memory T-cell and mediates response to chemotherapy in immune-quiescent nasopharyngeal carcinoma

INTRODUCTION

The immunosuppressive tumor microenvironment is a major barrier for chemotherapy. Different chemosensitization approaches to reinstate immunological surveillance for cancers that are immune quiescent at the outset, have thus been devised. Cancer-specific ENOX2 expression is correlated with abnormal cell growth and has been proposed as a cellular target for anti-cancer activity. However, the potential effects of ENOX2 on the interaction between immune system and tumor cells remain elusive.

OBJECTIVES

To understand the mechanisms by which tumor-intrinsic ENOX2-mediated alterations in anti-tumor activity of T-cells and response to chemotherapy.

METHODS

In situ multiplexed immunohistochemistry with single cell and bulk RNA sequencing data from nasopharyngeal carcinoma (NPC) human tissues were used to define tumor phenotypes. Two NPC cell lines, with distinct ENOX2 expression, were used in a co-culture platform to study tumor-immune interactions between cancer cells/spheroids and T-cells. The effect of cisplatin treatment with ENOX2 inhibition by idronoxil (IDX) were tested in vitro and in vivo. Multi-parametric flow cytometry was used to characterize T-cell infiltrates in an NPC tumor humanized mouse model treated with combined treatment.

RESULTS

NPC predominantly displayed an immune-excluded profile. This "cold-phenotype" was shown to exhibit higher ENOX2 expression and was associate with poorer progression-free survival (PFS). The therapeutic combination of IDX with cisplatin was effective in promoting CD8+ effector memory T cell (Tem) differentiation and mobilization. This Tem signature was highly cytotoxic, with Tem-mediated preferential lysis of higher ENOX2-expressing NPC cells. A combination-treated humanized mouse model showing dramatic shrinkage in tumors, were intra-tumoral Tem-enriched.

CONCLUSION

Tumor-intrinsic ENOX2 expression is associated with tumor phenotype and PFS in NPC. Targeting ENOX2 with IDX and cisplatin impose qualitative control of T-cell response by preferentially increasing immune cells infiltration, Tem differentiation and tumor suppression. We suggest that ENOX2 inhibition may be a promising therapeutic strategy to enhance the effects of chemotherapy.

Response of planktonic microbial assemblages to disturbance in an urban sub-tropical estuary

Microbes are sensitive indicators of estuarine processes because they respond rapidly to dynamic disturbance events. As most of the world's population lives in urban areas and climate change-related disturbance events are becoming more frequent, estuaries bounded by cities are experiencing increasing stressors, at the same time that their ecosystem services are required more than ever. Here, using a multidisciplinary approach, we determined the response of planktonic microbial assemblages in response to seasonality and a rainfall disturbance in an urban estuary bounded by Australia's largest city, Sydney. We used molecular barcoding (16S, 18S V4 rRNA) and microscopy-based identification to compare microbial assemblages at locations with differing characteristics and urbanisation histories. Across 142 samples, we identified 8,496 unique free-living bacterial zOTUs, 8,175 unique particle associated bacterial zOTUs, and 1,920 unique microbial eukaryotic zOTUs. Using microscopy, we identified only the top <10% abundant, larger eukaryotic taxa (>10 µm), however quantification was possible. The site with the greater history of anthropogenic impact showed a more even community of associated bacteria and eukaryotes, and a significant increase in dissolved inorganic nitrogen following rainfall, when compared to the more buffered site. This coincided with a reduced proportional abundance of Actinomarina and Synechococcus spp., a change in SAR 11 clades, and an increase in the eukaryotic microbial groups Dinophyceae, Mediophyceae and Bathyoccocaceae, including a temporary dominance of the harmful algal bloom dinoflagellate Prorocentrum cordatum (syn. P. minimum). Finally, a validated hydrodynamic model of the estuary supported these results, showing that the more highly urbanised and upstream location consistently experienced a higher magnitude of salinity reduction in response to rainfall events during the study period. The best abiotic variables to explain community dissimilarities between locations were TDP, PN, modelled temperature and salinity (r = 0.73) for the free living bacteria, TP for the associated bacteria (r = 0.43), and modelled temperature (r = 0.28) for the microbial eukaryotic communities. Overall, these results show that a minor disturbance such as a brief rainfall event can significantly shift the microbial assemblage of an anthropogenically impacted area within an urban estuary to a greater degree than a seasonal change, but may result in a lesser response to the same disturbance at a buffered, more oceanic influenced location. Fine scale research into the factors driving the response of microbial communities in urban estuaries to climate related disturbances will be necessary to understand and implement changes to maintain future estuarine ecosystem services.

Isoflavonoid-based therapeutics to remodel immunologically cold tumors in nasopharyngeal carcinoma

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Background: Nasopharyngeal carcinoma (NPC) is endemic in Southern China and is well-known to be heavily infiltrated by lymphocytes and constitute a unique but poorly defined tumor microenvironment. We aimed at delineating and defining the contribution of idronoxil (IDX), a synthetic flavonoid derivative, in restoring sensitivity to apoptosis and potentially modulating the immune microenvironment of NPC. Methods: Using multiplexed staining, we measured the levels of ENOX2 (IDX’s target), CD8 (cytotoxic T cell) and pan-cytokeratin (tumor marker) in 86 NPC patients’ cancerous specimens in tissue microarray format. NPC tissue bulk RNA-Seq and affymetrix microarray public datasets were gathered to examine ENOX2 significance. Interaction between ENOX2-expressing tumor cell lines (C17 and NPC43) and T cells were also studied. In vivo, antitumor effects of IDX on the growth of NPC43+ve tumors in nude mice and humanized mice were studied. Results: We performed median density as cut-off and tumors can be classified as hot or cold. 68.6% “cold”-phenotype tumors were observed in our cohort and the top 20% patients with highly positive ENOX2-expresing tumor cells showed lower number of CD8 infiltrates. Publicly dataset showed that highly expressed ENOX2 group associated with poorer prognosis (log-rank test p = 0.041). In vitro, we observed increased migration of T cells towards cancer cells when tumor cells were pre-treated with the combination of IDX and cisplatin (IDX+Cis) compared with monotherapy (IDX or cis alone) or untreated. We also observed increased susceptibility of tumor cells to T cell cytotoxicity when both IDX and Cis were added. In nude mice, IDX+Cis significantly decreased the tumor growth compared to saline-treated group. In humanized mice, upon treatment, we found 1.69-fold (p = 0.039) more CD3+ T cells in the tumor than in the blood when compared to control group. In humanized mice, the ratio between human T cell levels in tumor and blood was increased by the IDX+Cis compared to control group (1.67-fold, p = 0.01 by t-test). Conclusions: Distinct immunospatial profiles could be associated with clinicopathologic characteristics. The ability of IDX to modulate T cell populations indicates the potential of IDX to enhance the efficacy of current chemotherapy treatments in NPC by upregulating cellular trafficking toward tumor.[Table: see text]

Idronoxil as an Anticancer Agent: Activity and Mechanisms

Idronoxil has been the subject of more than 50 peer-reviewed publications over the last two decades. This isoflavone is an intriguing regulator of multiple signal transduction pathways, capable of causing a range of biological effects, including cell cycle arrest, apoptosis, an ability to stimulate the immune system, and inhibition of angiogenesis. These multifaceted actions suggest that idronoxil has the potential to synergize with, or complement, a wide range of cancer therapies. Whilst clinically tested in the past, idronoxil's journey was discontinued as a result of its low bioavailability in humans when administered either intravenously or orally, though strategies to overcome this issue are currently being explored. Here, we summarize the current literature regarding the key cellular targets of idronoxil and the mechanisms by which idronoxil exerts its anticancer effects, laying a new foundation toward giving this unique molecule a second chance of contributing to the future of cancer treatment.

Effect of idronoxil combined with cisplatin on refractory immune responses in nasopharyngeal carcinoma

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Background: Nasopharyngeal carcinoma (NPC) is endemic in Southern China. Although it is both radio-and chemo-sensitive, resistance to these treatments remains a major problem for successful management of NPC. The main characteristic of a cancer cell is its resistance to undergo apoptosis; therefore, reversing this resistance may represent the best approach for the treatment of cancer. Additionally, NPC is well-known to be heavily infiltrated by lymphocytes and constitute a unique but poorly defined tumor microenvironment (TME). We aimed at delineating and defining the contribution of idronoxil (IDX) in restoring sensitivity to apoptosis and potentially modulating the immune microenvironment of NPC. Methods: The IC50 of cisplatin (Cis) and IDX from 2D and 3D spheroid cultures of four NPC cancer cell lines (C666, C17, and the paired NPC43 EBV-positive and EBV-negative cell lines) were evaluated. The migration and proliferation of cells treated with IDX and/or Cis were investigated by Transwell and XTT, respectively. Cell phenotype and migratory analyses were measured by flow cytometry on Cis/IDX-pretreated NPC cell lines cocultured with HLA-matched PBMC. Results: IDX and Cis inhibited NPC migration and cell proliferation (IC50 for IDX in 2D and 3D was 2µM; IC50 for Cis in 2D and 3D: was 0.6µM and 1.4µM, respectively). A dose-dependent induction of apoptosis in NPC cell lines by IDX was observed [early apoptotic cells (Annexin V+/PI- at 1µM); late apoptotic cells (Annexin V+/PI+ at 2µM), and necrotic cells (Annexin V-/PI+, at 4µM) were distinguished]. Intriguingly, IDX increased the migratory potential of PBMC towards tumor cells in both 2D and 3D spheroid cultures. Finally, IDX, but not Cis, facilitated the migration of CD8+ T cells toward tumor cells by 3.5-fold (p < 0.05) as well as promoted the expansion of proliferative CD8+ T cells (increased by ~2.8-fold) with degranulation activities (~1.3-fold and 3-fold increase in surface CD107a and intracellular granzyme B expression, respectively) in the cocultures. Conclusions: IDX was shown to induce apoptosis in NPC cells while inhibiting their migration and proliferation. Moreover, the ability of IDX to modulate T cell populations indicates the drug’s potential to enhance the efficacy of current chemotherapy treatments in NPC by upregulating cellular trafficking to the cancer cell.

Qualitative and quantitative assessment of the presence of ciguatoxin, P-CTX-1B, in Spanish Mackerel (Scomberomorus commerson) from waters in New South Wales (Australia)

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P-CTX-1B in 84 Spanish Mackerel from NSW and QLD were quantified using LC–MS/MS.

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Liver & flesh from 6 fish and liver from 4 other fish were positive for P-CTX-1B.

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Liver had significantly higher concentration (∼6 times) of P-CTX-1B than flesh.

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No relationship was observed between length/weight of fish & detection of P-CTX-1B.

Ciguatera Fish Poisoning (CFP) is a tropical disease caused by the consumption of fish contaminated with ciguatoxins (CTXs). Currently, the only feasible prevention methods for CFP are to avoid the consumption of fish of certain species from some regions, avoid larger fish of certain species, or avoid all fish caught from specific regions. Here, we quantified levels of P-CTX-1B in Spanish Mackerel (Scomberomorus commerson), which is the main fish species that causes CFP in New South Wales and Queensland, Australia, using LC–MS detection against a toxin standard. We found detectable P-CTX-1B in both flesh and liver tissues in fish from New South Wales (n = 71, 1.4% prevalence rate, with a confidence interval of 1%–4%, and 7% prevalence, 1%–12%, in flesh and liver, respectively). In the small sample of fish from Queensland, there was a 46% prevalence (19–73%, n = 13). Toxin levels found were 0.13 μg kg⁻¹ to <0.1 μg kg⁻¹ in flesh, and 1.39 μg kg⁻¹ to <0.4 μg kg⁻¹ in liver, indicating that liver tissue had a significantly higher concentration (∼5 fold) of P-CTX-1B. No apparent relationship was observed between the length or weight of S. commerson and the detection of P-CTX-1B in this study.

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Dimethylsulfoniopropionate, superoxide dismutase and glutathione as stress response indicators in three corals under short-term hyposalinity stress

Corals are among the most active producers of dimethylsulfoniopropionate (DMSP), a key molecule in marine sulfur cycling, yet the specific physiological role of DMSP in corals remains elusive. Here, we examine the oxidative stress response of three coral species (Acropora millepora, Stylophora pistillata and Pocillopora damicornis) and explore the antioxidant role of DMSP and its breakdown products under short-term hyposalinity stress. Symbiont photosynthetic activity declined with hyposalinity exposure in all three reef-building corals. This corresponded with the upregulation of superoxide dismutase and glutathione in the animal host of all three species. For the symbiont component, there were differences in antioxidant regulation, demonstrating differential responses to oxidative stress between the Symbiodinium subclades. Of the three coral species investigated, only A. millepora provided any evidence of the role of DMSP in the oxidative stress response. Our study reveals variability in antioxidant regulation in corals and highlights the influence life-history traits, and the subcladal differences can have on coral physiology. Our data expand on the emerging understanding of the role of DMSP in coral stress regulation and emphasizes the importance of exploring both the host and symbiont responses for defining the threshold of the coral holobiont to hyposalinity stress.

Improved bacteria detection by coupling magneto-immunocapture and amperometry at flow-channel microband electrodes

This paper describes the first immunosensing system reported for the detection of bacteria combining immunomagnetic capture and amperometric detection in a one-step sandwich format, and in a microfluidic environment. Detection is based on the electrochemical monitoring of the activity of horseradish peroxidase (HRP), an enzyme label, through its catalysis of hydrogen peroxide (H(2)O(2)) in the presence of the mediator hydroquinone (HQ). The enzymatic reaction takes place in an incubation micro-chamber where the magnetic particles (MPs) are confined, upstream from the working electrode. The enzyme product is then pumped along a microchannel, where it is amperometrically detected by a set of microelectrodes. This design avoids direct contact of the biocomponents with the electrode, which lowers the risk of electrode fouling. The whole assay can be completed in 1h. The experiments performed with Escherichia coli evidenced a linear response for concentrations ranging 10(2)-10(8) cell ml(-1), with a limit of detection of 55 cells ml(-1) in PBS, without pre-enrichment steps. Furthermore, 100 cells ml(-1) could be detected in milk, and with negligible interference by non-target bacteria such as Pseudomonas.

Gold immuno-functionalisation via self-assembled monolayers: study of critical parameters and comparative performance for protein and bacteria detection

Surface functionalisation is of extreme importance in assay and biosensor development because it ensures the selective capture and detection of the targets of interest. In the present report, we compare the performance of several gold functionalisation strategies/chemistries, based on SAM self-assembly and Ab conjugation, for protein and bacteria detection. The first part of the work summarises the optimisation of the various protocols considered. Their efficiency was initially evaluated in terms of reduction of biomolecule non-specific adsorption and specific detection competence impairment, using as a model-target an enzyme-labelled protein. With this purpose, the effect of several parameters, such as thiomolecule length and concentration, self-assembly time and temperature, polymer incorporation, or Ab conjugation strategy was determined. The three best performing strategies consisted of antibody (Ab) conjugation to self-assembled monolayers (SAM) containing mercaptoundecanoic acid alone, or conjugated to either long-chain hydrophilic diamines or CM-dextran. In the three cases, results demonstrated that Abs had been successfully incorporated and remained functional for protein detection. Nevertheless, as showed in the second part of the work, we demonstrate for the first time that these chemistries can be inadequate for bacteria detection. The possible reasons and implications will be discussed. Ab physisorption is proposed as a cost-effective gold immuno-functionalisation strategy alternative to SAM-based Ab incorporation for bacteria detection.

Use of protoplasts from paired heterogenic bacterial species to detect tin contaminants: Prospects for biosensor development

Two different bacteria gave different respiratory responses to the test analytes, tributyl tin (TBT) and cadmium as expressed by positive sigmoid responses by Halomonas sp. (slope, +1.71 [TBT]; +1.76 [Cd]) and negative sigmoid responses by Bacillus pumilis (slope, -1.06 [TBT]; -0.59 [Cd]). The EC50 values determined from Hill plots for the response of Halomonas sp. to the TBT and Cd were 1 and 8.5 mM, respectively, which were lower by a factor of 10 than the corresponding values for B. pumilis. With protoplasts of B. pumilis there was a major shift in the signal from sigmoid negative to positive with TBT (+1.35) but not Cd (-0.5), while the signals with the remaining protoplast-analyte combinations remained unchanged. For all four protoplast-analyte combinations the EC50 values were in the order of 10-100-fold lower than those for their whole cell counterparts. When other analytes were tested the protoplasts gave a similar response to tin as for TBT, but detected copper and 2,4-dichlorophenol with similar signal profiles to Cd and with lower sensitivity. The difference in signal and higher sensitivity of the two species protoplast system towards TBT/tin compared to the other analytes tested, suggests that it may feasible to develop this approach for the detection of tin residues.