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Several soluble factors secreted by the stromal cells and cancer cells within the tumor microenvironment facilitate the progression and invasiveness of ovarian cancer. In ovarian cancer cells, lysophosphatidic acid (LPA) modulates the transcriptome profile and promotes cell invasiveness by the downregulation of autophagy. Here, we further elucidate this mechanism by focusing on the molecular and cellular events regulating autophagy. Transcriptomic and Western blotting analyses revealed NKX3-2, a transcriptional factor, to be among the genes hyperexpressed in LPA-stimulated ovarian cancer cells. Bioinformatic analyses revealed that in ovarian cancer patients, the expression of NKX3-2 positively correlates with genes involved in cell motility and migration, while it negatively correlates with macromolecular catabolic pathways. In various ovarian cancer cell lines, NKX3-2 silencing abrogated LPA-induced cell migration. Mechanistically, this effect is linked to the restoration of the HDAC6-mediated relocation of the lysosomes in the para-golgian area, and this results in an increase in autolysosome formation and the overall upregulation of autophagy. Silencing the expression of ATG7 or BECN1 , two autophagy genes, rescued the migratory phenotype of the NKX3-2-silenced ovarian cancer cells. Taken together, these data reveal the mechanism by which the LPA-NKX3-2 axis promotes the invasiveness of ovarian cancer cells and supports the possibility of targeting NKX3-2 to reduce the migratory capacity of cancer cells in response to a permissive microenvironment.

Diffuse large B-cell lymphoma (DLBCL) is characterized by high molecular and clinical heterogeneity. Autophagy, a lysosome-driven catabolic process devoted to macromolecular turnover, is fundamental in maintaining normal hematopoietic stem cells and progenitors homeostasis, and its dysregulation plays a critical role in the initiation and progression of hematological malignancies. One main regulator of autophagy is BECLIN-1, which may interact alternatively with either BCL-2, thus allowing apoptosis, or PI3KC3, thus promoting autophagy. The altered expression of BCL2 and BECN1 correlates with lymphoma outcomes, but whether this is associated with dysregulated cross-talk between autophagy and apoptosis remains to be elucidated. Analysis of the TCGA database revealed that BCL2 and BECN1 mRNA expression were inversely correlated in DLBCL patients. In representative DLBCL cell lines exposed to doxorubicin, the cells highly expressing BCL-2 were resistant, while the ones highly expressing BECLIN-1 were sensitive, and this correlated with low and high autophagy flux, respectively. Venetoclax targeting of BCL-2 increased while the spautin-1-mediated inhibition of BECLIN-1-dependent autophagy reversed doxorubicin sensitivity in the former and in the latter, respectively. By interrogating the TCGA DLBCL dataset, we found that BCL2 and BECN1 acted as negative and positive prognostic markers for DLBCL, respectively. The differentially expressed gene analysis in the respective cohorts revealed that BCL2 positively correlated with oncogenic pathways (e.g., glucose transport, HIF1A signaling, JAK-STAT signaling, PI3K-AKT-mTOR pathway) and negatively correlated with autophagy-related transcripts, while BECN1 showed the opposite trend. Notably, patients with high BECN1 expression displayed longer survival. Our data reveal, for the first time, that the modulation of BECLIN-1-dependent autophagy influences the prognosis of DLBCL patients and provide a mechanistic explanation supporting the therapeutic use of drugs that, by stimulating autophagy, can sensitize lymphoma cells to chemotherapy. [ABSTRACT FROM AUTHOR]

Neuroblastoma is a malignant extracranial solid tumor arising from the sympathoadrenal lineage of the neural crest and is often associated with N-MYC amplification. Cathepsin D has been associated with chemoresistance in N-MYC-overexpressing neuroblastomas. Increased EGFR expression also has been associated with the aggressive behavior of neuroblastomas. This work aimed to understand the mechanisms linking EGFR stimulation and cathepsin D expression with neuroblastoma progression and prognosis. Gene correlation analysis in pediatric neuroblastoma patients revealed that individuals bearing a high EGFR transcript level have a good prognosis only when CTSD (the gene coding for the lysosomal protease Cathepsin D, CD) is highly expressed. Low CTSD expression was associated with poor clinical outcome. CTSD expression was negatively correlated with CCNB2, CCNA2, CDK1 and CDK6 genes involved in cell cycle division. We investigated the biochemical pathways downstream to EGFR stimulation in human SH-SY5Y neuroblastoma cells engineered for overexpressing or silencing of CD expression. Cathepsin D overexpression decreased the proliferative potential of neuroblastoma cells through downregulation of the pro-oncogenic MAPK signaling pathway. EGFR stimulation downregulated cathepsin D expression, thus favoring cell cycle division. Our data suggest that chemotherapeutics that inhibit the EGFR pathway, along with stimulators of cathepsin D synthesis and activity, could benefit neuroblastoma prognosis. [ABSTRACT FROM AUTHOR]