Distinct effects of etoposide on glutamine-addicted neuroblastoma

Developing targeted therapies for neuroblastoma by dissecting the effects of metabolic reprogramming on tumor microenvironments and progression

Rationale: Synergic reprogramming of metabolic dominates neuroblastoma (NB) progression. It is of great clinical implications to develop an individualized risk prognostication approach with stratification-guided therapeutic options for NB based on elucidating molecular mechanisms of metabolic reprogramming. Methods: With a machine learning-based multi-step program, the synergic mechanisms of metabolic reprogramming-driven malignant progression of NB were elucidated at single-cell and metabolite flux dimensions. Subsequently, a promising metabolic reprogramming-associated prognostic signature (MPS) and individualized therapeutic approaches based on MPS-stratification were developed and further validated independently using pre-clinical models. Results: MPS-identified MPS-I NB showed significantly higher activity of metabolic reprogramming than MPS-II counterparts. MPS demonstrated improved accuracy compared to current clinical characteristics [AUC: 0.915 vs. 0.657 (MYCN), 0.713 (INSS-stage), and 0.808 (INRG-stratification)] in predicting prognosis. AZD7762 and etoposide were identified as potent therapeutics against MPS-I and II NB, respectively. Subsequent biological tests revealed AZD7762 substantially inhibited growth, migration, and invasion of MPS-I NB cells, more effectively than that of MPS-II cells. Conversely, etoposide had better therapeutic effects on MPS-II NB cells. More encouragingly, AZD7762 and etoposide significantly inhibited in-vivo subcutaneous tumorigenesis, proliferation, and pulmonary metastasis in MPS-I and MPS-II samples, respectively; thereby prolonging survival of tumor-bearing mice. Mechanistically, AZD7762 and etoposide-induced apoptosis of the MPS-I and MPS-II cells, respectively, through mitochondria-dependent pathways; and MPS-I NB resisted etoposide-induced apoptosis by addiction of glutamate metabolism and acetyl coenzyme A. MPS-I NB progression was fueled by multiple metabolic reprogramming-driven factors including multidrug resistance, immunosuppressive and tumor-promoting inflammatory microenvironments. Immunologically, MPS-I NB suppressed immune cells via MIF and THBS signaling pathways. Metabolically, the malignant proliferation of MPS-I NB cells was remarkably supported by reprogrammed glutamate metabolism, tricarboxylic acid cycle, urea cycle, etc. Furthermore, MPS-I NB cells manifested a distinct tumor-promoting developmental lineage and self-communication patterns, as evidenced by enhanced oncogenic signaling pathways activated with development and self-communications. Conclusions: This study provides deep insights into the molecular mechanisms underlying metabolic reprogramming-mediated malignant progression of NB. It also sheds light on developing targeted medications guided by the novel precise risk prognostication approaches, which could contribute to a significantly improved therapeutic strategy for NB.

Identification of Metabolism-Associated Biomarkers for Early and Precise Diagnosis of Oral Squamous Cell Carcinoma

The 5-year survival rate for oral squamous cell carcinoma (OSCC), one of the most common head and neck cancers, has not improved in the last 20 years. Poor prognosis of OSCC is the result of failure in early and precise diagnosis. Metabolic reprogramming, including the alteration of the uptake and utilisation of glucose, amino acids and lipids, is an important feature of OSCC and can be used to identify its biomarkers for early and precise diagnosis. In this review, we summarise how recent findings of rewired metabolic networks in OSCC have facilitated early and precise diagnosis of OSCC.

Comparative study of the ameliorative effects of omega-3 versus selenium on etoposide-induced changes in Sertoli cells and ectoplasmic specialization of adult rat testes: immunohistochemical and electron microscopic study

Etoposide (Eto) is an anti-cancer drug that is associated with serious adverse effects on male reproductive function. Omega-3 polyunsaturated fatty acids (ω-3 PUFAs) and selenium (Se) are known as anti-inflammatory, anti-apoptotic and anti-oxidant agents. This work was designed to investigate changes in the biochemical parameters as well as alterations in Sertoli cell vimentin expression, ultrastructure and ectoplasmic specializations (ESs) following Eto treatment and to assess the ameliorative effect of ω-3 versus Se on these alterations. Eighty four adult male albino rats were used and classified into four groups: group I (control group), group II (Eto group) received Eto in a single intra-peritoneal (IP) dose (60 mg/kg B.W.), group III (Eto & ω-3 group) received the single IP dose of Eto as well as ω-3 (300 mg/kg B.W./day by intra-gastric intubation) starting 5 days before Eto injection till the time of sacrifice & group IV (Eto & Se group) received the single IP dose of Eto as well as Se (0.5 mg/kg B.W./day IP) starting 5 days before Eto injection till the time of sacrifice. The rats were subdivided into 2 subgroups (a) and (b) that were sacrificed 3 and 7 days after Eto injection respectively. Eto administration in group II induced increase in malondialdehyde (MDA), decrease in superoxide dismutase (SOD), collapse of Sertoli cell vimentin filaments and ultrastructural degenerative changes in both Sertoli cells and ESs. Se (group IV) reversed Eto toxic effects potently, while ω-3 (group III) had some limited protective effects.

Targeting Oncogenic Transcriptional Networks in Neuroblastoma: From N-Myc to Epigenetic Drugs

Neuroblastoma (NB) is one of the most frequently occurring neurogenic extracranial solid cancers in childhood and infancy. Over the years, many pieces of evidence suggested that NB development is controlled by gene expression dysregulation. These unleashed programs that outline NB cancer cells make them highly dependent on specific tuning of gene expression, which can act co-operatively to define the differentiation state, cell identity, and specialized functions. The peculiar regulation is mainly caused by genetic and epigenetic alterations, resulting in the dependency on a small set of key master transcriptional regulators as the convergence point of multiple signalling pathways. In this review, we provide a comprehensive blueprint of transcriptional regulation bearing NB initiation and progression, unveiling the complexity of novel oncogenic and tumour suppressive regulatory networks of this pathology. Furthermore, we underline the significance of multi-target therapies against these hallmarks, showing how novel approaches, together with chemotherapy, surgery, or radiotherapy, can have substantial antineoplastic effects, disrupting a wide variety of tumorigenic pathways through combinations of different treatments.

The inhibition of GHR enhanced cytotoxic effects of etoposide on neuroblastoma

Etoposide, a DNA damage-inducing agent, is widely used to treat neuroblastoma. Etoposide binds to and inhibits topoisomerase II, thereby inducing the DNA damage response. However, the underlying mechanism of etoposide resistance in neuroblastoma remains unclear. The results of the present study revealed that etoposide upregulated growth hormone receptor (GHR) expression levels in etoposide-resistant neuroblastoma cells, suggesting that GHR upregulation may be involved in the underlying mechanism of etoposide resistance. Thus, the combined effect of GHR knockdown and etoposide treatment on cell viability, apoptosis and migration in vitro, as well as tumor growth in mouse xenograft models in vivo, was subsequently analyzed. The results of cell viability and colony formation assays demonstrated that GHR knockdown enhanced the inhibitory effects of etoposide on cell viability and sensitized cells to etoposide. The enhanced cell viability was discovered to be, at least in part, due to the increase in etoposide-induced apoptosis following GHR knockdown. Moreover, the knockdown of GHR enhanced the inhibitory effect of etoposide on cell migration. Mouse xenograft studies confirmed the effects of GHR silencing in etoposide-resistant neuroblastoma progression in vivo. Furthermore, the effects of GHR knockdown in etoposide resistance were hypothesized to occur via the inactivation of the MEK/ERK signaling pathway. In conclusion, the results of the present study provided novel insight into the underlying mechanism of etoposide resistance and a potential target for the treatment of etoposide-resistant neuroblastoma.

Aglycemic growth enhances carbohydrate metabolism and induces sensitivity to menadione in cultured tumor-derived cells

Background

Hepatocellular carcinoma (HCC) is the most prevalent form of liver malignancy and carries poor prognoses due to late presentation of symptoms. Treatment of late-stage HCC relies heavily on chemotherapeutics, many of which target cellular energy metabolism. A key platform for testing candidate chemotherapeutic compounds is the intrahepatic orthotopic xenograft (IOX) model in rodents. Translational efficacy from the IOX model to clinical use is limited (in part) by variation in the metabolic phenotypes of the tumor-derived cells that can be induced by selective adaptation to subculture conditions.

Methods

In this study, a detailed multilevel systems approach combining microscopy, respirometry, potentiometry, and extracellular flux analysis (EFA) was utilized to examine metabolic adaptations that occur under aglycemic growth media conditions in HCC-derived (HEPG2) cells. We hypothesized that aglycemic growth would result in adaptive “aerobic poise” characterized by enhanced capacity for oxidative phosphorylation over a range of physiological energetic demand states.

Results

Aglycemic growth did not invoke adaptive changes in mitochondrial content, network complexity, or intrinsic functional capacity/efficiency. In intact cells, aglycemic growth markedly enhanced fermentative glycolytic substrate-level phosphorylation during glucose refeeding and enhanced responsiveness of both fermentation and oxidative phosphorylation to stimulated energy demand. Additionally, aglycemic growth induced sensitivity of HEPG2 cells to the provitamin menadione at a 25-fold lower dose compared to control cells.

Conclusions

These findings indicate that growth media conditions have substantial effects on the energy metabolism of subcultured tumor-derived cells, which may have significant implications for chemotherapeutic sensitivity during incorporation in IOX testing panels. Additionally, the metabolic phenotyping approach used in this study provides a practical workflow that can be incorporated with IOX screening practices to aid in deciphering the metabolic underpinnings of chemotherapeutic drug sensitivity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40170-021-00241-0.