In the last years, mitochondrial ultrastructural and morphological changes have been implied in the control of several physiological and pathological changes, including the progression of apoptosis, inflammation, differentiation, tumorigenesis. However, the role of mitochondrial dynamics in the control of complex cellular cues and in response to reversible and irreversible cellular damage is not yet clarified. We will overview the key experiments that shed light on the role of mitochondrial shape and ultrastructure in cell physiology, pathology and in disease and offer a personal perspective on the missing pieces of the puzzle that await to be studied.

Breast cancer is the most prevalent cancer in the female population. The prolonged action of estrogens may affect tumor proliferation. Additionally, a fat-rich diet may show various effects on cancer proliferation, depending on the type of fat. Vitamin D, similarly to estrogens, is a fat-soluble cholesterol derivative. The deficiency of vitamin D correlates with increased proliferation of breast cancer cells. In turn, doxorubicin is commonly used cytostatic in chemotherapy. The study aimed to assess whether vitamin D enhances the anti-cancer effect of doxorubicin (DOX) in the MCF-7 cell line.

The cells were divided into four groups: untreated control, DOX- and vitamin D-treated cells, and cells treated with the combination of compounds in a 1:1 ratio. We applied MTT colorimetric assay (cell viability analysis), Annexin V/PI assay (cell death analysis), flow cytometry (cell cycle distribution), and fluorescence staining of cytoskeletal proteins (F-actin and vimentin). The type of DOX and vitamin D interaction was estimated based on the Chou-Talalay method.

Our results showed that vitamin D and doxorubicin in a 1:1 ratio act synergistically. We observed a decrease in the survival of MCF7 cells. The combination of DOX and vitamin D enhanced changes in morphology and organization in F-actin and vimentin network compared to the treatment with the substances separately.

In summary, we suggest that natural compounds such as vitamin D may be useful in anticancer treatment in the context of enhancing the cytostatic effects of drugs.

The nerve growth factor (NGF) was initially identified as a promoter of neuronal survival and differentiation. As such, it captured for a long time the interest of neurobiologists. Nowadays, NGF is considered as a multifaceted molecule with pleiotropic effects in quite divergent cell types, including hormone-dependent cancer cells. Many tumors exhibit derangements of nerve growth factor and its receptors, including the tropomyosin receptor kinase A (TrkA). This receptor is frequently expressed in triple-negative breast cancers (TNBC) as well as prostate cancers (PC), although its role in pathogenesis and aggressiveness of these diseases is still under investigation.

We now report that treatment of TNBC as well as PC-derived cells with NGF triggers proliferation and survival of these cells. Simultaneously, NGF fosters cell motility and induces invasiveness in these cells by acting on the release of metalloproteases-9 (MMP-9). Somatic knockdown of TrkA or its pharmacologic inhibition by the specific inhibitor, GW441756 impair these effects. A strong reduction in TNBC or PC-derived spheroid size is observed upon GW441756 treatment.

The relevance of our studies is based on the novelty that further exploration of NGF pathway derangements in gender-related cancers will likely offer to envision innovative targets and treatment opportunities in clinical management of TNBC as well as PC patients.

Cerebral cavernous malformation (CCM, OMIM #116860) is a vascular disorder of central nervous system capillaries. Affected vessels appear tangled and enlarged due to cell junction impairment, resulting in an increased blood-brain barrier (BBB) permeability, further worsened by deficiency of pericytes. The familial form of the disease arises following germline mutations at the three loci KRIT1/CCM1 (HGNC ID: 1573; 7q11.2-21), MGC4607/CCM2 (HGNC ID: 21708; 7p13) and PDCD10/CCM3 (HGNC ID: 8761; 3q26.1). However, a small percentage of patients affected by the inherited form of the disease harbors no mutations, suggesting the existence of a fourth CCM locus. In this context, by whole exome sequencing we identified the novel missense mutation c.2973C>T (p.Phe991Leu) in the PIEZO1 gene (HGNC ID: 28993; 16q24.3) and it was shown to segregate with the CCM phenotype, within the family. PIEZO1 encodes for a mechanosensitive Ca2+ ion channel that, in endothelial cells, contributes to maintaining BBB integrity. We found that PIEZO1 impairment results in increased apoptotic rate of endothelial cells, as well as in CCM gene expression perturbation. Moreover, by immunofluorescence, we showed that PIEZO1 impairment leads to endothelial cell morphology loss and to KRIT1 nuclear translocation. We used human cerebral microvascular endothelial cells (hCMECs) as cell model, Yoda1 as PIEZO1 agonist and gadolinium as PIEZO1 antagonist. Untreated cells were consider as control condition. According to our results, we think that PIEZO1 can be considered for further investigation in CCM pathogenesis.

Mutations in genes encoding nuclear envelope (NE) proteins, despite being rare, represent a major threat to cell homeostasis by compromising nuclear integrity and function as well as nucleocytoplasmic communication. In the last decade, several diseases have been associated to mutations in the TOR1AIP1 gene that codes for lamina-associated polypeptide 1 (LAP1), a NE protein ubiquitously expressed in human tissues. Although this is suggestive of an important physiological role of LAP1, it remains unclear which cellular activities are regulated by this protein. To address this, we investigated the molecular repercussions of its deficiency in patient-derived skin fibroblasts carrying a pathological LAP1 mutation (p.E482A), previously reported in a case of severe dystonia, cerebellar atrophy and cardiomyopathy. Using liquid chromatography with tandem mass spectrometry (LC–MS/MS), a quantitative proteome analysis was performed to identify up-/downregulated proteins in LAP1 E482A fibroblasts relative to age-matched control fibroblasts. A subsequent functional characterization of the LC–MS/MS-identified differentially expressed proteins using bioinformatics tools unraveled various signaling pathways/biological processes potentially deregulated in LAP1 E482A fibroblasts, such as DNA repair, neurodevelopment and myogenesis, among others. This work sheds light on dysfunctional molecular mechanisms in LAP1-deficient cells, which will contribute to a better understanding of LAP1’s physiological relevance for the maintenance of cell homeostasis and, hopefully, allow to uncover potential therapeutic targets for LAP1-associated pathologies.