CO2-Induced Transcriptional Reorganization: Molecular Basis of Capnophillic Lactic Fermentation in Thermotoga neapolitana

Capnophilic lactic fermentation (CLF) is a novel anaplerotic pathway able to convert sugars to lactic acid (LA) and hydrogen using CO2 as carbon enhancer in the hyperthermophilic bacterium Thermotoga neapolitana. In order to give further insights into CLF metabolic networks, we investigated the transcriptional modification induced by CO2 using a RNA-seq approach. Transcriptomic analysis revealed 1601 differentially expressed genes (DEGs) in an enriched CO2 atmosphere over a total of 1938 genes of the T. neapolitana genome. Transcription of PFOR and LDH genes belonging to the CLF pathway was up-regulated by CO2 together with 6-phosphogluconolactonase (6PGL) and 6-phosphogluconate dehydratase (EDD) of the Entner–Doudoroff (ED) pathway. The transcriptomic study also revealed up-regulation of genes coding for the flavin-based enzymes NADH-dependent reduced ferredoxin:NADP oxidoreductase (NFN) and NAD-ferredoxin oxidoreductase (RNF) that control supply of reduced ferredoxin and NADH and allow energy conservation-based sodium translocation through the cell membrane. These results support the hypothesis that CO2 induces rearrangement of the central carbon metabolism together with activation of mechanisms that increase availability of the reducing equivalents that are necessary to sustain CLF. In this view, this study reports a first rationale of the molecular basis of CLF in T. neapolitana and provides a list of target genes for the biotechnological implementation of this process

Gastrointestinal stromal tumors (GISTs) and second malignancies A novel sentinel tumor? A monoinstitutional, STROBE-compliant observational analysis

Several evidences showed that patients with gastrointestinal stromal tumors (GISTs) develop additional malignancies. However, thorough incidence of second tumors remains uncertain as the possibility of a common molecular pathogenesis. A retrospective series of 128 patients with histologically proven GIST treated at our institution was evaluated. Molecular analysis of KIT and PDGFR-a genes was performed in all patients. Following the involvement of KRAS mutation in many tumors' pathogenesis, analysis of KRAS was performed in patients with also second neoplasms. Forty-six out of 128 GIST patients (35.9%) had a second neoplasm. Most second tumors (52%) raised from gastrointestinal tract and 19.6% from genitourinary tract. Benign neoplasms were also included (21.7%). Molecular analysis was available for 29/46 patients with a second tumor: wild-type GISTs (n. 5), exon 11 (n. 16), exon 13 (n. 1), exon 9 (n. 1) KIT mutations, exon 14 PDGFR-a mutation (n. 2) and exon 18 PDGFR-a mutation (n. 4). KIT exon 11 mutations were more frequent between patients who developed a second tumor (P=0.0003). Mutational analysis of KRAS showed a wild-type sequence in all cases. In metachronous cases, the median time interval between GIST and second tumor was 21.5 months. The high frequency of second tumors suggests that an unknown common molecular mechanism might play a role, but it is not likely that KRAS is involved in this common pathogenesis. The short interval between GIST diagnosis and the onset of second neoplasms asks for a careful follow-up, particularly in the first 3 years after diagnosis

Refining patient selection for next-generation immunotherapeutic early-phase clinical trials with a novel and externally validated prognostic nomogram

IntroductionIdentifying which patient may benefit from immunotherapeutic early-phase clinical trials is an unmet need in drug development. Among several proposed prognostic scores, none has been validated in patients receiving immunomodulating agents (IMAs)-based combinations.Patients and methodsWe retrospectively collected data of 208 patients enrolled in early-phase clinical trials investigating IMAs at our Institution, correlating clinical and blood-based variables with overall survival (OS). A retrospective cohort of 50 patients treated with IMAs at Imperial College (Hammersmith Hospital, London, UK) was used for validation.ResultsA total of 173 subjects were selected for analyses. Most frequent cancers included non-small cell lung cancer (26%), hepatocellular carcinoma (21.5%) and glioblastoma (13%). Multivariate analysis (MVA) revealed 3 factors to be independently associated with OS: line of treatment (second and third vs subsequent, HR 0.61, 95% CI 0.40-0.93, p 0.02), serum albumin as continuous variable (HR 0.57, 95% CI 0.36–0.91, p 0.02) and number of metastatic sites (<3 vs ≥3, HR 0.68, 95% CI 0.48-0.98, p 0.04). After splitting albumin value at the median (3.84 g/dL), a score system was capable of stratifying patients in 3 groups with significantly different OS (p<0.0001). Relationship with OS reproduced in the external cohort (p=0.008). Then, from these factors we built a nomogram.ConclusionsPrior treatment, serum albumin and number of metastatic sites are readily available prognostic traits in patients with advanced malignancies participating into immunotherapy early-phase trials. Combination of these factors can optimize patient selection at study enrollment, maximizing therapeutic intent

COVID-19 lung injury as a primer for immune checkpoint inhibitors (ICIs)-related pneumonia in a patient affected by squamous head and neck carcinoma treated with PD-L1 blockade: a case report

By the beginning of the global pandemic, SARS-CoV-2 infection has dramatically impacted on oncology daily practice. In the current oncological landscape, where immunotherapy has revolutionized the treatment of several malignancies, distinguishing between COVID-19 and immune-mediated pneumonitis can be hard because of shared clinical, radiological and pathological features. Indeed, their common mechanism of aberrant inflammation could lead to a mutual and amplifying interaction.We describe the case of a 65–year-old patient affected by metastatic squamous head and neck cancer and candidate to an experimental therapy including an anti-PD-L1 agent. COVID-19 ground-glass opacities under resolution were an incidental finding during screening procedures and worsened after starting immunotherapy. The diagnostic work-up was consistent with ICIs-related pneumonia and it is conceivable that lung injury by SARS-CoV-2 has acted as an inflammatory primer for the development of the immune-related adverse event.Patients recovered from COVID-19 starting ICIs could be at greater risk of recall immune-mediated pneumonitis. Nasopharyngeal swab and chest CT scan are recommended before starting immunotherapy. The awareness of the phenomenon could allow an easier interpretation of radiological changes under treatment and a faster diagnostic work-up to resume ICIs. In the presence of clinical benefit, for asymptomatic ICIs-related pneumonia a watchful-waiting approach and immunotherapy prosecution are suggested

Hydrogen and lactic acid synthesis by the wild-type and a laboratory strain of the hyperthermophilic bacterium Thermotoga neapolitana DSMZ 4359 T under capnophilic lactic fermentation conditions

Thermotoga neapolitana is a hyperthermophilic eubacterium that produces hydrogen by sugar fermentation. A lab strain of T. neapolitana DSMZ 4359T maintained in a CO2-enriched atmosphere showed a stable increase of lactic acid production under capnophilic lactic fermentation (CLF) conditions. The genotypic comparison between the putative mutant (TN-CMut) and the original strain DSMZ 4359T (WT4359) revealed 88.1 (±2.4)% DNA homology. RiboPrint® and MALDI-TOF mass analyses support a genetic differentiation beyond subspecies level. The phenotypic characterization indicated a high correlation between the two strains, except for the lactic acid production. Under identical operating conditions, the lab mutant produced significantly more lactic acid than the parent strain without impairing the hydrogen yield. The highest divergence between TN-CMut and WT4359 was observed for fermentation of glucose or lactose at 80 °C. Based on these results, we propose that the lab strain is a new subspecies of the genus Thermotoga that is named T. neapolitana subsp. capnolactica with regards to its improved feature to produce lactic acid under capnophilic conditions

Adsorption Behaviour of Lactic Acid on Granular Activated Carbon and Anionic Resins: Thermodynamics, Isotherms and Kinetic Studies

Solid-liquid extraction (adsorption or ion exchange) is a promising approach for the in situ separation of organic acids from fermentation broths. In this study, a diluted concentration of lactic acid ( 0.96) and the pseudo-second order kinetic model (R2 ∼ 1) fitted better to the experimental data than the other models tested. Postulating the conditions for the real fermentation broth (pH: 5.0-6.5 and temperature: 30-80°C), the resin AMB400 represents an ideal candidate for the extraction of lactic acid during fermentation

Kinetic modeling of hydrogen and L-lactic acid production by Thermotoga neapolitana via capnophilic lactic fermentation of starch

This study investigated the feasibility of hydrogen (H2) and L-lactic acid production from starch under capnophilic lactic fermentation (CLF) conditions by using Thermotoga neapolitana. Batch experiments were performed in 120 mL serum bottles and a 3 L pH-controlled continuous stirred-tank reactors (CSTR) system with potato and wheat starch as the substrates. A H2 yield of 3.34 (±0.17) and 2.79 (±0.17) mol H2/mol of glucose eq. was achieved with, respectively, potato and wheat starch. In the presence of CO2, L-lactic acid production by the acetyl-CoA carboxylation was significantly higher for the potato starch (0.88 ± 0.39 mol lactic acid/mol glucose eq.) than wheat starch (0.33 ± 0.11 mol lactic acid/mol glucose eq.). A kinetic model was applied to simulate and predict the T. neapolitana metabolic profile and bioreactor performance under CLF conditions. The CLF-based starch fermentation suggests a new direction to biotransform agri-food waste into biofuels and valuable biochemicals

Hydrogen Production by the Thermophilic Bacterium Thermotoga neapolitana

As the only fuel that is not chemically bound to carbon, hydrogen has gained interest as an energy carrier to face the current environmental issues of greenhouse gas emissions and to substitute the depleting non-renewable reserves. In the last years, there has been a significant increase in the number of publications about the bacterium Thermotoga neapolitana that is responsible for production yields of H2 that are among the highest achievements reported in the literature. Here we present an extensive overview of the most recent studies on this hyperthermophilic bacterium together with a critical discussion of the potential of fermentative production by this bacterium. The review article is organized into sections focused on biochemical, microbiological and technical issues, including the effect of substrate, reactor type, gas sparging, temperature, pH, hydraulic retention time and organic loading parameters on rate and yield of gas production

Checkpoint Inhibitors as High-Grade Gliomas Treatment: State of the Art and Future Perspectives

Glioblastoma (GBM) is the most common and aggressive malignant brain tumor in adults. Despite significant efforts, no therapies have demonstrated valuable survival benefit beyond the current standard of care. Immune checkpoint inhibitors (ICI) have revolutionized the treatment landscape and improved patient survival in many advanced malignancies. Unfortunately, these clinical successes have not been replicated in the neuro-oncology field so far. This review summarizes the status of ICI investigation in high-grade gliomas, critically presenting the available data from preclinical models and clinical trials. Moreover, we explore new approaches to increase ICI efficacy, with a particular focus on combinatorial strategies, and the potential biomarkers to identify patients most likely to benefit from immune checkpoint blockade

Continuous hydrogen production by immobilized cultures of Thermotoga neapolitana on an acrylic hydrogel with pH-buffering properties

This communication reports on the continuous biohydrogen production by Thermotoga neapolitana cells immobilized on a stable cationic hydrogel bearing amine groups. This hydrogel was designed to perform two functional activities: to promote adhesion of T. neapolitana cells, and to buffer pH changes in the bacterial cultures. Repeated fed-batch cultures showed an average hydrogen production rate and yield of 50.6 mL L−1 h−1 and 3.3 mol H2/mol glucose, respectively. To the best of our knowledge, this is the first report detailing the immobilization of this bacterial strain on a polymeric support