Heparanase promotes myeloma stemness and in vivo tumorigenesis.

Heparanase is known to enhance the progression of many cancer types and is associated with poor patient prognosis. We recently reported that after patients with multiple myeloma were treated with high dose chemotherapy, the tumor cells that emerged upon relapse expressed a much higher level of heparanase than was present prior to therapy. Because tumor cells having stemness properties are thought to seed tumor relapse, we investigated whether heparanase had a role in promoting myeloma stemness. When plated at low density and grown in serum-free conditions that support survival and expansion of stem-like cells, myeloma cells expressing a low level of heparanase formed tumor spheroids poorly. In contrast, cells expressing a high level of heparanase formed significantly more and larger spheroids than did the heparanase low cells. Importantly, heparanase-low expressing cells exhibited plasticity and were induced to exhibit stemness properties when exposed to recombinant heparanase or to exosomes that contained a high level of heparanase cargo. The spheroid-forming heparanase-high cells had elevated expression of GLI1, SOX2 and ALDH1A1, three genes known to be associated with myeloma stemness. Inhibitors that block the heparan sulfate degrading activity of heparanase significantly diminished spheroid formation and expression of stemness genes implying a direct role of the enzyme in regulating stemness. Blocking the NF-κB pathway inhibited spheroid formation and expression of stemness genes demonstrating a role for NF-κB in heparanase-mediated stemness. Myeloma cells made deficient in heparanase exhibited decreased stemness properties in vitro and when injected into mice they formed tumors poorly compared to the robust tumorigenic capacity of cells expressing higher levels of heparanase. These studies reveal for the first time a role for heparanase in promoting cancer stemness and provide new insight into its function in driving tumor progression and its association with poor prognosis in cancer patients.

Heme oxygenase and iron status in exosomes of psoriasis patients.

Psoriasis is an autoimmune skin disease characterized by hyperproliferation of keratinocytes due to interplay between keratinocytes and immune cells. Iron status plays an important role in modifying the function of the immune system. Heme oxygenase (HO), heme-degrading enzyme, plays important role in protective response to oxidative cellular stress. We aimed in this study to map the iron status and HO levels and declare the role HO enzyme in iron homeostasis and immune-modulation in psoriasis. Fifty-one patients with psoriasis and 50 age- and sex-matched healthy controls were enrolled in this study. 5 mL blood sample was withdrawn from each subject. Hepcidin, iron soluble transferring receptor (sTfR), and total iron binding capacity (TIBC) were estimated using ELISA technique and, HO-1 gene level was detected using RT-PCR (reverse transcription-polymerase chain reaction). Iron levels, TIBC, and hepcidin were significantly lower in cases compared to controls. On the contrary, sTfR and HO-1 were significantly over-expressed in cases compared to controls (p < 0.05 in all). HO-1 expression negatively correlated with PASI score and disease extent (%) (r = - 0.614-, p = 0.001; r = - 0.807-, p = 0.001 respectively). There were no significant associations between HO-1 expression and iron, TIBC, hepcidin, sTfR levels (p > 0.05 in all). Iron supplements for the patients with psoriasis are important to maintain haematopoiesis. The induction of HO-1 might have be a promising approach for the treatment of psoriasis through antioxidant ability, immunomodulatory role as well as its role in heme synthesis.

Mutant copper-zinc superoxide dismutase (SOD1) induces protein secretion pathway alterations and exosome release in astrocytes: implications for disease spreading and motor neuron pathology in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis is the most common motor neuron disease and is still incurable. The mechanisms leading to the selective motor neuron vulnerability are still not known. The interplay between motor neurons and astrocytes is crucial in the outcome of the disease. We show that mutant copper-zinc superoxide dismutase (SOD1) overexpression in primary astrocyte cultures is associated with decreased levels of proteins involved in secretory pathways. This is linked to a general reduction of total secreted proteins, except for specific enrichment in a number of proteins in the media, such as mutant SOD1 and valosin-containing protein (VCP)/p97. Because there was also an increase in exosome release, we can deduce that astrocytes expressing mutant SOD1 activate unconventional secretory pathways, possibly as a protective mechanism. This may help limit the formation of intracellular aggregates and overcome mutant SOD1 toxicity. We also found that astrocyte-derived exosomes efficiently transfer mutant SOD1 to spinal neurons and induce selective motor neuron death. We conclude that the expression of mutant SOD1 has a substantial impact on astrocyte protein secretion pathways, contributing to motor neuron pathology and disease spread.