Ferroptosis resistance in cancer cells: nanoparticles for combination therapy as a solution.

Ferroptosis is a form of regulated cell death (RCD) characterized by iron-dependent lipid peroxidation. Ferroptosis is currently proposed as one of the most promising means of combating tumor resistance. Nevertheless, the problem of ferroptosis resistance in certain cancer cells has been identified. This review first, investigates the mechanisms of ferroptosis induction in cancer cells. Next, the problem of cancer cell resistance to ferroptosis, as well as the underlying mechanisms is discussed. Recently discovered ferroptosis-suppressing biomarkers have been described. The various types of nanoparticles that can induce ferroptosis are also discussed. Given the ability of nanoparticles to combine multiple agents, this review proposes nanoparticle-based ferroptosis cell death as a viable method of circumventing this resistance. This review suggests combining ferroptosis with other forms of cell death, such as apoptosis, cuproptosis and autophagy. It also suggests combining ferroptosis with immunotherapy.

Coordinated modulation of long non-coding RNA ASBEL and curcumin co-delivery through multicomponent nanocomplexes for synchronous triple-negative breast cancer theranostics.

BACKGROUND: Abnormally regulated long non-coding RNAs (lncRNAs) functions in cancer emphasize their potential to serve as potential targets for cancer therapeutic intervention. LncRNA ASBEL has been identified as oncogene and an anti-sense transcript of tumor-suppressor gene of BTG3 in triple-negative breast cancer (TNBC). RESULTS: Herein, multicomponent self-assembled polyelectrolyte nanocomplexes (CANPs) based on the polyelectrolytes of bioactive hyaluronic acid (HA) and chitosan hydrochloride (CS) were designed and prepared for the collaborative modulation of oncogenic lncRNA ASBEL with antago3, an oligonucleotide antagonist targeting lncRNA ASBEL and hydrophobic curcumin (Cur) co-delivery for synergetic TNBC therapy. Antago3 and Cur co-incorporated CANPs were achieved via a one-step assembling strategy with the cooperation of noncovalent electrostatic interactions, hydrogen-bonding, and hydrophobic interactions. Moreover, the multicomponent assembled CANPs were ulteriorly decorated with a near-infrared fluorescence (NIRF) Cy-5.5 dye (FCANPs) for synchronous NIRF imaging and therapy monitoring performance. Resultantly, MDA-MB-231 cells proliferation, migration, and invasion were efficiently inhibited, and the highest apoptosis ratio was induced by FCANPs with coordination patterns. At the molecular level, effective regulation of lncRNA ASBEL/BTG3 and synchronous regulation of Bcl-2 and c-Met pathways could be observed. CONCLUSION: As expected, systemic administration of FCANPs resulted in targeted and preferential accumulation of near-infrared fluorescence signal and Cur in the tumor tissue. More attractively, systemic FCANPs-mediated collaborative modulating lncRNA ASBEL/BTG3 and Cur co-delivery significantly suppressed the MDA-MB-231 xenograft tumor growth, inhibited metastasis and extended survival rate with negligible systemic toxicity. Our present study represented an effective approach to developing a promising theranostic platform for combating TNBC in a combined therapy pattern.

CD16 CAR-T cells enhance antitumor activity of CpG ODN-loaded nanoparticle-adjuvanted tumor antigen-derived vaccinevia ADCC approach.

BACKGROUND: Combinatorial immunotherapy strategies for enhancing the responsiveness of immune system have shown great promise for cancer therapy. Engineered nanoformulation incorporated toll-like receptor (TLR) 9 agonist CpG ODN has shown more positive results in suppressing tumor growth and can significantly enhance other immunotherapy activity with combinatorial effects due to the innate and adaptive immunostimulatory effects of CpG. RESULTS: In the present work, protamine sulfate (PS) and carboxymethyl ß-glucan (CMG) were used as nanomaterials to form nanoparticles through a self-assembly approach for CpG ODN encapsulation to generate CpG ODN-loaded nano-adjuvant (CNPs), which was subsequently mixed with the mixture of mouse melanoma-derived antigens of tumor cell lysates (TCL) and neoantigens to develop vaccine for anti-tumor immunotherapy. The obtained results showed that CNPs was able to effectively deliver CpG ODN into murine bone marrow-derived dendritic cells (DC) in vitro, and remarkably stimulate the maturation of DC cells with proinflammatory cytokine secretion. In addition, in vivo analysis showed that CNPs enhanced anti-tumor activity of PD1 antibody and CNPs-adjuvanted vaccine based on the mixture antigens of melanoma TCL and melanoma-specific neoantigen could not only induce anti-melanoma cellular immune responses, but also elicit melanoma specific humoral immune responses, which significantly inhibited xenograft tumor growth. Furthermore, CD16 CAR-T cells were generated by expressing CD16-CAR in CD3+CD8+ murine T cells. CONCLUSION: Our results eventually showed that anti-melanoma antibodies induced by CNPs-adjuvanted TCL vaccines were able to collaborate with CD16-CAR-T cells to generate an enhanced targeted anti-tumor effects through ADCC (antibody dependent cell cytotoxicity) approach. CD16 CAR-T cells has thus a great potential to be an universal promising strategy targeting on solid tumor synergistic immunotherapy via co-operation with TCL-based vaccine.

Targeting Fusobacterium nucleatum through chemical modifications of host-derived transfer RNA fragments.

Host mucosal barriers possess an arsenal of defense molecules to maintain host-microbe homeostasis such as antimicrobial peptides and immunoglobulins. In addition to these well-established defense molecules, we recently reported small RNAs (sRNAs)-mediated interactions between human oral keratinocytes and Fusobacterium nucleatum (Fn), an oral pathobiont with increasing implications in extra-oral diseases. Specifically, upon Fn infection, oral keratinocytes released Fn-targeting tRNA-derived sRNAs (tsRNAs), an emerging class of noncoding sRNAs with gene regulatory functions. To explore potential antimicrobial activities of tsRNAs, we chemically modify the nucleotides of the Fn-targeting tsRNAs and demonstrate that the resultant tsRNA derivatives, termed MOD-tsRNAs, exhibit growth inhibitory effect against various Fn type strains and clinical tumor isolates without any delivery vehicle in the nanomolar concentration range. In contrast, the same MOD-tsRNAs do not inhibit other representative oral bacteria. Further mechanistic studies uncover the ribosome-targeting functions of MOD-tsRNAs in inhibiting Fn. Taken together, our work provides an engineering approach to targeting pathobionts through co-opting host-derived extracellular tsRNAs.

Acquisition of the arginine deiminase system benefits epiparasitic Saccharibacteria and their host bacteria in a mammalian niche environment.

Saccharibacteria are a group of widespread and genetically diverse ultrasmall bacteria with highly reduced genomes that belong to the Candidate Phyla Radiation. Comparative genomic analyses suggest convergent evolution of key functions enabling the adaptation of environmental Saccharibacteria to mammalian microbiomes. Currently, our understanding of this environment-to-mammal niche transition within Saccharibacteria and their obligate episymbiotic association with host bacteria is limited. Here, we identified a complete arginine deiminase system (ADS), found in further genome streamlined mammal-associated Saccharibacteria but missing in their environmental counterparts, suggesting acquisition during environment-to-mammal niche transition. Using TM7x, the first cultured Saccharibacteria strain from the human oral microbiome and its host bacterium Actinomyces odontolyticus, we experimentally tested the function and impact of the ADS. We demonstrated that by catabolizing arginine and generating adenosine triphosphate, the ADS allows metabolically restrained TM7x to maintain higher viability and infectivity when disassociated from the host bacterium. Furthermore, the ADS protects TM7x and its host bacterium from acid stress, a condition frequently encountered within the human oral cavity due to bacterial metabolism of dietary carbohydrates. Intriguingly, with a restricted host range, TM7x forms obligate associations with Actinomyces spp. lacking the ADS but not those carrying the ADS, suggesting the acquired ADS may also contribute to partner selection for cooperative episymbiosis within a mammalian microbiome. These data present experimental characterization of a mutualistic interaction between TM7x and their host bacteria, and illustrate the benefits of acquiring a novel pathway in the transition of Saccharibacteria to mammalian microbiomes.

Episymbiotic Saccharibacteria suppresses gingival inflammation and bone loss in mice through host bacterial modulation.

Saccharibacteria (TM7) are obligate epibionts living on the surface of their host bacteria and are strongly correlated with dysbiotic microbiomes during periodontitis and other inflammatory diseases, suggesting they are putative pathogens. However, due to the recalcitrance of TM7 cultivation, causal research to investigate their role in inflammatory diseases is lacking. Here, we isolated multiple TM7 species on their host bacteria from periodontitis patients. These TM7 species reduce inflammation and consequential bone loss by modulating host bacterial pathogenicity in a mouse ligature-induced periodontitis model. Two host bacterial functions involved in collagen binding and utilization of eukaryotic sialic acid are required for inducing bone loss and are altered by TM7 association. This TM7-mediated downregulation of host bacterial pathogenicity is shown for multiple TM7/host bacteria pairs, suggesting that, in contrast to their suspected pathogenic role, TM7 could protect mammalian hosts from inflammatory damage induced by their host bacteria.

A novel decision tree model based on chromosome imbalances in cell-free DNA and CA-125 in the differential diagnosis of ovarian cancer.

OBJECTIVE: CA-125 is widely used as biomarker of ovarian cancer. However, CA-125 suffers low accuracy. We developed a hybrid analytical model, the Ovarian Cancer Decision Tree (OCDT), employing a two-layer decision tree, which considers genetic alteration information from cell-free DNA along with CA-125 value to distinguish malignant tumors from benign tumors. METHODS: We consider major copy number alterations at whole chromosome and chromosome-arm level as the main feature of our detection model. Fifty-eight patients diagnosed with malignant tumors, 66 with borderline tumors, and 10 with benign tumors were enrolled. RESULTS: Genetic analysis revealed significant arm-level imbalances in most malignant tumors, especially in high-grade serous cancers in which 12 chromosome arms with significant aneuploidy (P<0.01) were identified, including 7 arms with significant gains and 5 with significant losses. The area under receiver operating characteristic curve (AUC) was 0.8985 for copy number variations analysis, compared to 0.8751 of CA125. The OCDT was generated with a cancerous score (CScore) threshold of 5.18 for the first level, and a CA-125 value of 103.1 for the second level. Our most optimized OCDT model achieved an AUC of 0.975. CONCLUSIONS: The results suggested that genetic variations extracted from cfDNA can be combined with CA-125, and together improved the differential diagnosis of malignant from benign ovarian tumors. The model would aid in the pre-operative assessment of women with adnexal masses. Future clinical trials need to be conducted to further evaluate the value of CScore in clinical settings and search for the optimal threshold for malignancy detection.

Gastrointestinal disturbance and effect of fecal microbiota transplantation in discharged COVID-19 patients.

BACKGROUND: To investigate the potential beneficial effect of fecal microbiota transplantation (FMT) on gastrointestinal symptoms, gut dysbiosis and immune status in discharged COVID-19 patients. CASE PRESENTATION: A total of 11 COVID-19 patients were recruited in April, 2020, about one month on average after they were discharged from the hospital. All subjects received FMT for 4 consecutive days by oral capsule administrations with 10 capsules for each day. In total, 5 out of 11 patients reported to be suffered from gastrointestinal symptoms, which were improved after FMT. After FMT, alterations of B cells were observed, which was characterized as decreased naive B cell (P = 0.012) and increased memory B cells (P = 0.001) and non-switched B cells (P = 0.012).The microbial community richness indicated by operational taxonomic units number, observed species and Chao1 estimator was marginally increased after FMT. Gut microbiome composition of discharged COVID-19 patients differed from that of the general population at both phylum and genera level, which was characterized with a lower proportion of Firmicutes (41.0%) and Actinobacteria (4.0%), higher proportion of Bacteroidetes (42.9%) and Proteobacteria (9.2%). FMT can partially restore the gut dysbiosis by increasing the relative abundance of Actinobacteria (15.0%) and reducing Proteobacteria (2.8%) at the phylum level. At the genera level, Bifidobacterium and Faecalibacterium had significantly increased after FMT. CONCLUSIONS: After FMT, altered peripheral lymphocyte subset, restored gut microbiota and alleviated gastrointestinal disorders were observe, suggesting that FMT may serve as a potential therapeutic and rehabilitative intervention for the COVID-19.

Human mesenchymal stem cells-derived conditioned medium inhibits hypoxia-induced death of neonatal porcine islets by inducing autophagy.

BACKGROUND: The dysfunction of islet grafts is generally attributed to hypoxia-induced damage. Mesenchymal stem cells (MSCs) are currently thought to effectively protect cells from various risk factors via regulating autophagy. In our study, we investigated if human umbilical cord-derived MSCs could ameliorate hypoxia-induced apoptosis in porcine islets by modulating autophagy, and we explored the underlying mechanisms. METHODS: Neonatal porcine islet cell clusters (NICCs) were cultured with human umbilical cord-derived MSC conditioned medium (huc-MSC-CM) and RPMI-1640 medium (control) under hypoxic conditions (1% O2 ) in vitro. NICCs were treated with 3-methyladenine (3-MA) and chloroquine (CQ) to examine the role of huc-MSC-CM in regulating autophagy. Finally, the levels of several cytokines secreted by huc-MSCs were detected by ELISAs, and the corresponding inhibitors were applied to investigate which cytokine mediates the protective effects of huc-MSC-CM. The effects of huc-MSC-CM on NICCs viability and autophagy were examined using AO/PI staining, flow cytometry analysis, transmission electron microscopy (TEM) and confocal fluorescence microscopy analysis. The insulin secretion of NICCs was tested with an insulin immunoradiometric assay kit. RESULTS: Compared to the control, the huc-MSC-CM treatment improved the viability of NICCs, inhibited apoptosis, increased autophagic activity and the levels of PI3K class III and phosphorylated Akt, while the ratio of phosphorylated mTOR/mTOR was reduced. These changes were reversed by CQ and 3-MA treatments. High concentrations of IL-6 were detected in hu-MSC-CM. Furthermore, recombinant IL-6 pre-treatment exerted similar effects as huc-MSC-CM, and these effects were reversed by a specific inhibitor of IL-6 (Sarilumab). CONCLUSIONS: Our results demonstrated that huc-MSC-CM improved islet viability and function by increasing autophagy through the PI3K/Akt/mTOR pathway under hypoxic conditions. Additionally, IL-6 plays an important role in the function of huc-MSC-CM.

Mesenchymal stem cells alleviate hypoxia-induced oxidative stress and enhance the pro-survival pathways in porcine islets.

IMPACT STATEMENT: The utilization of mesenchymal stem cells (MSCs) is a promising approach to serve as adjuvant therapy for islet transplantation. But the inability to translate promising preclinical results into sound therapeutic effects in human subjects indicates a lack of key knowledge of MSC-islet interactions that warrant further research. Hypoxia and oxidative stress are critical factors which lead to a tremendous loss of islet grafts. However, previous studies mainly focused on other aspects of MSC protection such as inducing revascularization, enhancing insulin secretion, and reducing islet apoptosis. In this study, we aim to investigate whether MSC can protect islet cells from hypoxic damage by inhibiting ROS production and the potential underlying pathways involved. We also explore the effects of MSC-derived exosomes and IL-6 on hypoxia-injured islets. Our data provide new molecular targets for developing MSC applications, and this may ultimately promote the efficiency of clinical islet transplantation.

Morphological and physiological changes induced by contact-dependent interaction between Candida albicans and Fusobacterium nucleatum.

Candida albicans and Fusobacterium nucleatum are well-studied oral commensal microbes with pathogenic potential that are involved in various oral polymicrobial infectious diseases. Recently, we demonstrated that F. nucleatum ATCC 23726 coaggregates with C. albicans SN152, a process mainly mediated by fusobacterial membrane protein RadD and Candida cell wall protein Flo9. The aim of this study was to investigate the potential biological impact of this inter-kingdom interaction. We found that F. nucleatum ATCC 23726 inhibits growth and hyphal morphogenesis of C. albicans SN152 in a contact-dependent manner. Further analysis revealed that the inhibition of Candida hyphal morphogenesis is mediated via RadD and Flo9 protein pair. Using a murine macrophage cell line, we showed that the F. nucleatum-induced inhibition of Candida hyphal morphogenesis promotes C. albicans survival and negatively impacts the macrophage-killing capability of C. albicans. Furthermore, the yeast form of C. albicans repressed F. nucleatum-induced MCP-1 and TNFα production in macrophages. Our study suggests that the interaction between C. albicans and F. nucleatum leads to a mutual attenuation of virulence, which may function to promote a long-term commensal lifestyle within the oral cavity. This finding has significant implications for our understanding of inter-kingdom interaction and may impact clinical treatment strategies.

Cultivation of a human-associated TM7 phylotype reveals a reduced genome and epibiotic parasitic lifestyle.

The candidate phylum TM7 is globally distributed and often associated with human inflammatory mucosal diseases. Despite its prevalence, the TM7 phylum remains recalcitrant to cultivation, making it one of the most enigmatic phyla known. In this study, we cultivated a TM7 phylotype (TM7x) from the human oral cavity. This extremely small coccus (200-300 nm) has a distinctive lifestyle not previously observed in human-associated microbes. It is an obligate epibiont of an Actinomyces odontolyticus strain (XH001) yet also has a parasitic phase, thereby killing its host. This first completed genome (705 kb) for a human-associated TM7 phylotype revealed a complete lack of amino acid biosynthetic capacity. Comparative genomics analyses with uncultivated environmental TM7 assemblies show remarkable conserved gene synteny and only minimal gene loss/gain that may have occurred as TM7x adapted to conditions within the human host. Transcriptomic and metabolomic profiles provided the first indications, to our knowledge, that there is signaling interaction between TM7x and XH001. Furthermore, the induction of TNF-α production in macrophages by XH001 was repressed in the presence of TM7x, suggesting its potential immune suppression ability. Overall, our data provide intriguing insights into the uncultivability, pathogenicity, and unique lifestyle of this previously uncharacterized oral TM7 phylotype.

The influence of iron availability on human salivary microbial community composition.

It is a well-recognized fact that the composition of human salivary microbial community is greatly affected by its nutritional environment. However, most studies are currently focused on major carbon or nitrogen sources with limited attention to trace elements like essential mineral ions. In this study, we examined the effect of iron availability on the bacterial profiles of an in vitro human salivary microbial community as iron is an essential trace element for the survival and proliferation of virtually all microorganisms. Analysis via a combination of PCR with denaturing gradient gel electrophoresis demonstrated a drastic change in species composition of an in vitro human salivary microbiota when iron was scavenged from the culture medium by addition of the iron chelator 2,2'-bipyridyl. This shift in community profile was prevented by the presence of excessive ferrous iron (Fe(2+)). Most interestingly, under iron deficiency, the in vitro grown salivary microbial community became dominated by several hemolytic bacterial species, including Streptococcus spp., Gemella spp., and Granulicatella spp. all of which have been implicated in infective endocarditis. These data provide evidence that iron availability can modulate host-associated oral microbial communities, resulting in a microbiota with potential clinical impact.

Quorum sensing in Rhizobium sp. strain NGR234 regulates conjugal transfer (tra) gene expression and influences growth rate.

Rhizobium sp. strain NGR234 forms symbiotic, nitrogen-fixing nodules on a wide range of legumes via functions largely encoded by the plasmid pNGR234a. The pNGR234a sequence revealed a region encoding plasmid replication (rep) and conjugal transfer (tra) functions similar to those encoded by the rep and tra genes from the tumor-inducing (Ti) plasmids of Agrobacterium tumefaciens, including homologues of the Ti plasmid quorum-sensing regulators TraI, TraR, and TraM. In A. tumefaciens, TraI, a LuxI-type protein, catalyzes synthesis of the acylated homoserine lactone (acyl-HSL) N-3-oxo-octanoyl-L-homoserine lactone (3-oxo-C8-HSL). TraR binds 3-oxo-C8-HSL and activates expression of Ti plasmid tra and rep genes, increasing conjugation and copy number at high population densities. TraM prevents this activation under noninducing conditions. Although the pNGR234a TraR, TraI, and TraM appear to function similarly to their A. tumefaciens counterparts, the TraR and TraM orthologues are not cross-functional, and the quorum-sensing systems have differences. NGR234 TraI synthesizes an acyl-HSL likely to be 3-oxo-C8-HSL, but traI mutants and a pNGR234a-cured derivative produce low levels of a similar acyl-HSL and another, more hydrophobic signal molecule. TraR activates expression of several pNGR234a tra operons in response to 3-oxo-C8-HSL and is inhibited by TraM. However, one of the pNGR234a tra operons is not activated by TraR, and conjugal efficiency is not affected by TraR and 3-oxo-C8-HSL. The growth rate of NGR234 is significantly decreased by TraR and 3-oxo-C8-HSL through functions encoded elsewhere in the NGR234 genome.