Biology subjects

Roversi, G. A.

Publications and source records attributed to Roversi, G. A..

4 recordsLinked to original sources

bioRxiv2020

Cancer Stem Cell Enrichment and Metabolic Substrate Adaptability are Driven by Hydrogen Sulfide Suppression in Glioblastoma

Glioblastoma (GBM) remains among the deadliest of human malignancies. The emergence of the cancer stem cell (CSC) phenotype represents a major challenge to disease management and durable treatment response. The extrinsic, environmental, and lifestyle factors that result in CSC enrichment are not well understood. The CSC state endows cells with a fluid metabolic profile, enabling the utilization of multiple nutrient sources. Therefore, to test the impact of diet on CSC enrichment, we evaluated disease progression in tumor-bearing mice fed an obesity-inducing high-fat diet (HFD) versus an energy-balanced, low-fat control diet. HFD consumption resulted in hyper-aggressive disease that was accompanied by CSC enrichment and shortened survival. HFD consumption also drove intracerebral accumulation of saturated fats, which in turn inhibited the production and signaling of the gasotransmitter hydrogen sulfide (H2S). H2S is an endogenously produced bio-active metabolite derived from sulfur amino acid catabolism. It functions principally through protein S-sulfhydration and regulates a variety of programs including mitochondrial bioenergetics and cellular metabolism. Inhibition of H2S synthesis resulted in increased proliferation and chemotherapy resistance, whereas treatment with H2S donors led to cytotoxicity and death of cultured GBM cells. Compared to non-cancerous controls, patient GBM specimens were reduced in overall protein S-sulfhydration, which was primarily lost from proteins regulating cellular metabolism. These findings support the hypothesis that diet-regulated H2S signaling serves to suppress GBM by restricting metabolic adaptability, while its loss triggers CSC enrichment and disease acceleration. Interventions augmenting H2S bioavailability concurrent with GBM standard of care may improve outcomes for GBM patients. One Sentence SummaryConsumption of a high-fat diet (HFD) accelerates glioblastoma (GBM) by inhibiting the production and signaling of the tumor-suppressive metabolite hydrogen sulfide (H2S).

cancer biology↗

bioRxiv2020

Myeloid-derived suppressor cell subsets drive glioblastoma growth in a sex-specific manner

Myeloid-derived suppressor cells (MDSCs) that block anti-tumor immunity are elevated in glioblastoma (GBM) patients. However, the distinct contribution of monocytic (mMDSC) versus granulocytic (gMDSC) subsets has yet to be determined. We observed that mMDSCs were enriched in the male tumor microenvironment, while gMDSCs were elevated in the circulation of female GBM models. Depletion of peripheral gMDSCs extended the survival only in female mice. Using gene expression signatures coupled with network medicine analysis, we demonstrated in pre-clinical models that mMDSCs could be targeted with anti-proliferative agents in males, whereas gMDSC function in females could be inhibited by IL-1{beta} blockade. Analysis of patient data confirmed that proliferating mMDSCs were the predominant population in male tumors, and that a high gMDSC/IL-1{beta} gene signature correlated with poor prognosis of female patients. These findings demonstrate that MDSC subsets differentially drive immune suppression in a sex-specific manner and can be leveraged for therapeutic intervention in GBM. Statement of SignificanceSexual dimorphism at the level of MDSC subset prevalence, localization and gene expression profile comprises a therapeutic opportunity. Our results indicate that chemotherapy can be used to target mMDSC in males, while IL-1 pathway inhibitors can provide benefit to females through blockade of gMDSC function.

immunology↗

bioRxiv2019

Metronomic capecitabine as an immune modulator in glioblastoma patients reduces myeloid-derived suppressor cells

BackgroundMyeloid-derived suppressor cells (MDSCs) are elevated in glioblastoma (GBM) patient circulation, present in tumor tissue, and associated with poor prognosis. While low-dose chemotherapy reduces MDSCs in preclinical models, the use of this strategy to reduce MDSCs in GBM patients has yet to be evaluated. MethodsA phase 0/1 dose-escalation clinical trial was conducted in recurrent glioblastoma patients treated 5-7 days prior to surgery with low-dose chemotherapy via capecitabine followed by concomitant low-dose capecitabine and bevacizumab. Clinical outcomes, including progression-free and overall survival, were measured, along with safety and toxicity profiles. Over the treatment time course, circulating MDSC levels were measured by multi-parameter flow cytometry, and tumor tissue immune profiles were assessed via mass cytometry time-of-flight. ResultsA total of 11 patients were enrolled across escalating dose cohorts of 150, 300, and 450 mg bid, with a progression-free survival of 5.8 months (range of 1.8-27.8 months) and an overall survival of 11.5 months (range of 3->28.0 months) from trial enrollment. No serious adverse events related to the drug combination were observed. Compared to pre-treatment baseline, circulating MDSCs were found to be higher after surgery in the 150 mg treatment arm and lower in the 300 mg and 450 mg treatment arms. Increased cytotoxic immune infiltration was observed after low-dose capecitabine compared to untreated GBM patients in the 300 mg and 450 mg treatment arms. ConclusionsLow-dose, metronomic capecitabine in combination with bevacizumab is well tolerated in GBM patients and was associated with a reduction in circulating MDSC levels and an increase in cytotoxic immune infiltration into the tumor microenvironment. Trial registrationNCT02669173 FundingThis research was funded by the Cleveland Clinic, Case Comprehensive Cancer Center, Musella Foundation, and B*CURED. Capecitabine was provided in kind by Mylan Pharmaceuticals.

clinical trials↗

bioRxiv2019

Malignant liver cancers have distinct myeloid-derived suppressor cell signatures

Myeloid-derived suppressor cells (MDSCs) are immunosuppressive cells that are increased in patients with numerous malignancies including viral-derived hepatocellular carcinoma (HCC). Here, we report an elevation of MDSC in other hepatobiliary malignancies including non-viral HCC, neuroendocrine tumors (NET), colorectal carcinoma with liver metastases (CRLM), but not cholangiocarcinoma (CCA). Investigation of myeloid cell infiltration in HCC, NET and intrahepatic CCA tumors further established that the frequency of antigen-presenting cells was limited compared to benign lesions suggesting that primary and metastatic hepatobiliary cancers have distinct peripheral and tumoral myeloid signatures. Bioinformatics analysis of the Cancer Genome Atlas demonstrated that a high MDSC score in HCC patients predicted poor disease outcome. Mechanistic studies indicated that the oncometabolite D-2-hydroxyglutarate resulting from isocitrate dehydrogenase 1 mutation could be a limiting factor of MDSC accumulation in CCA patients. Given our observation that MDSCs are increased in non-CCA malignant liver cancers, they may comprise suitable targets for effective immunotherapy approaches.

pathology↗