Michele Vidone

Self-renewal of CD133(hi) cells by IL6/Notch3 signalling regulates endocrine resistance in metastatic breast cancer.

The mechanisms of metastatic progression from hormonal therapy (HT) are largely unknown in luminal breast cancer. Here we demonstrate the enrichment of CD133hi/ERlo cancer cells in clinical specimens following neoadjuvant endocrine therapy and in HT refractory metastatic disease. We develop experimental models of metastatic luminal breast cancer and demonstrate that HT can promote the generation of HT-resistant, self-renewing CD133hi/ERlo/IL6hi cancer stem cells (CSCs). HT initially abrogates oxidative phosphorylation (OXPHOS) generating self-renewal-deficient cancer cells, CD133hi/ERlo/OXPHOSlo. These cells exit metabolic dormancy via an IL6-driven feed-forward ERlo-IL6hi-Notchhi loop, activating OXPHOS, in the absence of ER activity. The inhibition of IL6R/IL6-Notch pathways switches the self-renewal of CD133hi CSCs, from an IL6/Notch-dependent one to an ER-dependent one, through the re-expression of ER. Thus, HT induces an OXPHOS metabolic editing of luminal breast cancers, paradoxically establishing HT-driven self-renewal of dormant CD133hi/ERlo cells mediating metastatic progression, which is sensitive to dual targeted therapy.

The RET51/FKBP52 complex and its involvement in Parkinson disease

The tyrosine kinase receptor RET51 is expressed in distinct families of neurons where it promotes different functions. FKBP52 is an immunophilin with neuroprotective effects on different kinds of neurons. In this paper, we demonstrate that RET51 activation by both glial cell line-derived neurotrophic factor (GDNF) and NGF triggers the formation of RET51/FKBP52 complex. The substitution of the tyrosine 905 of RET51, a key residue phosphorylated by both GDNF and NGF, disrupts the RET51/FKBP52 complex. NGF and GDNF have a functional role in dopaminergic (DA) neurons where RET51 and FKBP52 are expressed with a yet undefined function. To clarify if RET51/FKBP52 complex should exert its function in DA neurons, we used an indirect approach by screening the genes encoding for RET51 and FKBP52 in a group of 30 Parkinsons disease patients. The degeneration of DA neurons is the main feature of PD, which is associated to a complex multifactorial aetiology combining environmental, age-related and genetic factors. We found a compound heterozygous carrying two mutations in RET and FKBP52 that are sufficient to disrupt the RET51/FKBP52 complex, indicating its potential role in PD.

A comprehensive characterization of mitochondrial DNA mutations in glioblastoma multiforme.

Glioblastoma multiforme (GBM) is the most malignant brain cancer in adults, with a poor prognosis, whose molecular stratification still represents a challenge in pathology and clinics. On the other hand, mitochondrial DNA (mtDNA) mutations have been found in most tumors as modifiers of the bioenergetics state, albeit in GBM a characterization of the mtDNA status is lacking to date. Here, a characterization of the burden of mtDNA mutations in GBM samples was performed. First, investigation of tumor-specific vs. non tumor-specific mutations was carried out with the MToolBox bioinformatics pipeline by analyzing 45 matched tumor/blood samples, from whole genome or whole exome sequencing datasets obtained from The Cancer Genome Atlas (TCGA) consortium. Additionally, the entire mtDNA sequence was obtained in a dataset of 104 fresh-frozen GBM samples. Mitochondrial mutations with potential pathogenic interest were prioritized based on heteroplasmic fraction, nucleotide variability, and in silico prediction of pathogenicity. A preliminary biochemical analysis of the activity of mitochondrial respiratory complexes was also performed on fresh-frozen GBM samples. Although a high number of mutations was detected, we report that the large majority of them does not pass the prioritization filters. Therefore, a relatively limited burden of pathogenic mutations is indeed carried by GBM, which did not appear to determine a general impairment of the respiratory chain. This article is part of a Directed Issue entitled: Energy Metabolism Disorders and Therapies.

Evidence of association of human papillomavirus with prognosis worsening in glioblastoma multiforme

BACKGROUND Glioblastoma multiforme (GBM) is the most malignant brain tumor in adults, but its etiology still remains unknown. Recently, a role of viruses such as cytomegalovirus and JC virus in gliomagenesis has been suggested. Since human papillomavirus (HPV) is considered the most common oncogenic virus in humans, we evaluated its occurrence in GBM samples. MATERIAL AND METHODS Fifty-two formalin-fixed paraffin-embedded primary glioblastoma specimens were retrospectively analyzed. The presence of HPV genome on tumor DNA was assessed by MY/GP nested PCR. Confirmation of HPV detection was obtained by chromogenic in situ hybridization (CISH) and immunohistochemistry (IHC) with an antibody directed against the L1 capsidic protein. Finally, univariate and multivariate proportional-hazards models were used to compare the risk of death among HPV-positive and HPV-negative patients. RESULTS Strikingly, viral DNA was detected after PCR in 12 cases (23%). HPV16 genome was present in 25% infected samples, whereas the remaining samples tested positive for HPV6. CISH confirmed positivity in all infected samples for which enough material was available. Moreover, IHC positivity suggested that production of viral proteins from HPV genome is an ongoing process in GBM cancer cells. Finally an association between HPV infection and a worse prognosis was found in patients upon age stratification with a univariate analysis (HR, 2.10; 95% CI, 1.00-4.44; log-rank P = .045). CONCLUSIONS HPV infection status may be considered an independent prognostic factor in GBM patients and suggests that prevention may be considered, should HPV be recognized as a causative agent in gliomagenesis.

The α-ketoglutarate dehydrogenase complex in cancer metabolic plasticity

Deregulated metabolism is a well-established hallmark of cancer. At the hub of various metabolic pathways deeply integrated within mitochondrial functions, the α-ketoglutarate dehydrogenase complex represents a major modulator of electron transport chain activity and tricarboxylic acid cycle (TCA) flux, and is a pivotal enzyme in the metabolic reprogramming following a cancer cell’s change in bioenergetic requirements. By contributing to the control of α-ketoglutarate levels, dynamics, and oxidation state, the α-ketoglutarate dehydrogenase is also essential in modulating the epigenetic landscape of cancer cells. In this review, we will discuss the manifold roles that this TCA enzyme and its substrate play in cancer.

Platinum-induced mitochondrial DNA mutations confer lower sensitivity to paclitaxel by impairing tubulin cytoskeletal organization

Development of chemoresistance is a cogent clinical issue in oncology, whereby combination of anticancer drugs is usually preferred also to enhance efficacy. Paclitaxel (PTX), combined with carboplatin, represents the standard first-line chemotherapy for different types of cancers. We here depict a double-edge role of mitochondrial DNA (mtDNA) mutations induced in cancer cells after treatment with platinum. MtDNA mutations were positively selected by PTX, and they determined a decrease in the mitochondrial respiratory function, as well as in proliferative and tumorigenic potential, in terms of migratory and invasive capacity. Moreover, cells bearing mtDNA mutations lacked filamentous tubulin, the main target of PTX, and failed to reorient the Golgi body upon appropriate stimuli. We also show that the bioenergetic and cytoskeletal phenotype were transferred along with mtDNA mutations in transmitochondrial hybrids, and that this also conferred PTX resistance to recipient cells. Overall, our data show that platinum-induced deleterious mtDNA mutations confer resistance to PTX, and confirm what we previously reported in an ovarian cancer patient treated with carboplatin and PTX who developed a quiescent yet resistant tumor mass harboring mtDNA mutations.

Mitochondrial Mutations in Cancer Progression: Causative, Bystanders, or Modifiers of Tumorigenesis?

Mitochondrial DNA encodes genes that are de facto metabolic enzymes and are currently emerging as pivotal players in the origin, progression, and outcome of human cancers. We here revise the multifaceted implications of mitochondrial mutations on the metabolic reprogramming cancer cells must undergo to adapt and proliferate. The sources of such mutations and the processes that govern their positive selection are described, along with the consequences that a deranged respiratory metabolism may have on the remodeling that follows oncogenes activation or tumor suppressors ablation. Ultimately, we dwell on the peculiar features of oncocytic tumors, one of the most relevant yet mysterious models to functionally investigate the role of mitochondrial mutations in cancer.

Abstract LB-236: Self-renewal of CD133hi cells by IL6/Notch3 signaling regulates endocrine resistance in metastatic breast cancers

The mechanisms of metastatic progression from hormonal therapy (HT)-induced tumour dormancy to hormonal therapy resistance is largely unknown in luminal breast cancer. Analysis of clinical specimens revealed the enrichment of CD133hi/ERlo cancer cells in primary tumours following neo-adjuvant endocrine therapy and in HT refractory metastatic disease. We developed spontaneous experimental models of metastatic luminal breast cancer and determined that endocrine therapy can promote the generation of HT- resistant, self-renewing CD133hi/ERlo/IL6hicells. Dual pharmacological inhibition of IL6R-IL6 (tocilizumab) and ER (HT) abrogated the establishment of CD133hi/ERlo/IL6hi cancer stem cells (CSCs), restoring endocrine sensitivity to hormone-refractory metastatic disease, in both experimental and patient-derived endocrine-resistant bone metastasis. Hormonal therapy, initially abrogated oxidative phosphorylation (OXPHOS) generating dormant (self-renewal deficient-CD133hi/ERlo/OXPHOSlo) cancer cells, These cells exited metabolic dormancy via an IL6 driven feed-forward ERlo-IL6hi-Notchhi loop, activating OXPHOS, in the absence of ER activity. Importantly, the inhibition of IL6R/IL6-Notch pathways switched the self-renewal of CD133hi CSCs, from an IL6/Notch-dependent one to an ER-dependent one, through the re-expression of ER. Thus, HT induces an OXPHOS metabolic editing of luminal breast cancers, paradoxically establishing HT-driven self-renewal of dormant CD133hi/ERlo cells mediating metastatic progression, which is sensitive to dual targeted therapy. Citation Format: Pasquale Sansone, Ceccarelli Claudio, Marjan Berishaj, Qing Chang, Rajasekhar Vinagolu, Fabiana Perna, Robert Bowman, Michele Vidone, Laura Daly, Jennifer Nnoli, Donatella Santini, Taffurelli Mario, Natalie Shih, Michael Feldman, Jun James Mao, Christopher Colameco, Jinbo Chen, Angela DeMichele, Nicola Fabbri, John Healey, Monica Cricca, Giuseppe Gasparre, David Lyden, Massimiliano Bonafe, Jacqueline F. Bromberg. Self-renewal of CD133hi cells by IL6/Notch3 signaling regulates endocrine resistance in metastatic breast cancers. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-236.