Altered tumor microenvironment (TME) arising from a bidirectional crosstalk between the pancreatic cancer cells (PCCs) and the pancreatic stellate cells (PSCs) is implicated in the dismal prognosis in pancreatic ductal adenocarcinoma (PDAC), yet effective strategies to disrupt the crosstalk is lacking. Here, we demonstrate that gold nanoparticles (AuNPs) inhibit proliferation and migration of both PCCs and PSCs by disrupting the bidirectional communication via alteration of the cell secretome. Analyzing the key proteins identified from a functional network of AuNP-altered secretome in PCCs and PSCs, we demonstrate that AuNPs impair secretions of major hub node proteins in both cell types and transform activated PSCs toward a lipid-rich quiescent phenotype. By reducing activation of PSCs, AuNPs inhibit matrix deposition, enhance angiogenesis, and inhibit tumor growth in an orthotopic co-implantation model in vivo. Auto- and heteroregulations of secretory growth factors/cytokines are disrupted by AuNPs resulting in reprogramming of the TME. By utilizing a kinase dead mutant of IRE1-α, we demonstrate that AuNPs alter the cellular secretome through the ER-stress-regulated IRE1-dependent decay pathway (RIDD) and identify endostatin and matrix metalloproteinase 9 as putative RIDD targets. Thus, AuNPs could potentially be utilized as a tool to effectively interrogate bidirectional communications in the tumor microenvironment, reprogram it, and inhibit tumor growth by its therapeutic function.

Chromosome 22q11.2 deletions are found in almost 90% of patients with DiGeorge/velocardiofacial syndrome (DGS/VCFS). Large, chromosome-specific low copy repeats (LCRs), flanking and within the deletion interval, are presumed to lead to misalignment and aberrant recombination in meiosis resulting in this frequent microdeletion syndrome. We traced the grandparental origin of regions flanking de novo 3 Mb deletions in 20 informative three-generation families. Haplotype reconstruction showed an unexpectedly high number of proximal interchromosomal exchanges between homologs, occurring in 19/20 families. Instead, the normal chromosome 22 in these probands showed interchromosomal exchanges in 2/15 informative meioses, a rate consistent with the genetic distance. Meiotic exchanges, visualized as MLH1 foci, localize to the distal long arm of chromosome 22 in 75% of human spermatocytes tested, also reflecting the genetic map. Additionally, we found no effect of proband gender or parental age on the crossover frequency. Parental origin studies in 65 de novo 3 Mb deletions (including these 20 patients) demonstrated no bias. Unlike Williams syndrome, we found no chromosomal inversions flanked by LCRs in 22 sets of parents of 22q11 deleted patients, or in eight non-deleted patients with a DGS/VCFS phenotype using FISH. Our data are consistent with significant aberrant interchromosomal exchange events during meiosis I in the proximal region of the affected chromosome 22 as the likely etiology for the deletion. This type of exchange occurs more often than is described for deletions of chromosomes 7q11, 15q11, 17p11 and 17q11, implying a difference in the meiotic behavior of chromosome 22.

Cancer cells actively promote aerobic glycolysis to sustain their metabolic requirements through mechanisms not always clear. Here, we demonstrate that the gatekeeper of mitochondrial Ca2+ uptake, Mitochondrial Calcium Uptake 1 (MICU1/CBARA1) drives aerobic glycolysis in ovarian cancer. We show that MICU1 is overexpressed in a panel of ovarian cancer cell lines and that MICU1 overexpression correlates with poor overall survival (OS). Silencing MICU1 in vitro increases oxygen consumption, decreases lactate production, inhibits clonal growth, migration and invasion of ovarian cancer cells, whereas silencing in vivo inhibits tumour growth, increases cisplatin efficacy and OS. Mechanistically, silencing MICU1 activates pyruvate dehydrogenase (PDH) by stimulating the PDPhosphatase-phosphoPDH-PDH axis. Forced-expression of MICU1 in normal cells phenocopies the metabolic aberrations of malignant cells. Consistent with the in vitro and in vivo findings we observe a significant correlation between MICU1 and pPDH (inactive form of PDH) expression with poor prognosis. Thus, MICU1 could serve as an important therapeutic target to normalize metabolic aberrations responsible for poor prognosis in ovarian cancer.

No abstract