The FHP01 DDX3X Helicase Inhibitor Exerts Potent Anti-Tumor Activity In Vivo in Breast Cancer Pre-Clinical Models

X and Y Differences in Melanoma Survival Between the Sexes

Marked differences in survival from melanoma are noted between men and women that cannot be accounted for by behavioral differences. We and others have provided evidence that this difference may be due to increased expression of immune-related genes from the second X chromosome because of failure of X inactivation. In the present review, we have examined evidence for the contrary view that survival differences are due to weaker immune responses in males. One reason for this may be the loss of Y chromosomes (LOY), particularly in older males. The genes involved may have direct roles in immune responses or be noncoding RNAs that regulate both sex and autosomal genes involved in immune responses or tumor growth. Loss of the KDM6C and KDM5D demethylases appeared to common genes involved. The second factor appears to be the activation of androgen receptors (AR) on melanoma cells that increase their invasiveness and growth. Induction of T-cell exhaustion by AR that limits immune responses against melanoma appeared a common finding. The development of treatments to overcome effects related to gene loss on Y poses challenges, but several avenues related to AR signaling appear worthy of further study in the treatment of metastatic disease.

Attenuation of protein arginine dimethylation via S-nitrosylation of protein arginine methyltransferase 1

Upregulation of nitric oxide (NO) production contributes to the pathogenesis of numerous diseases via S-nitrosylation, a post-translational modification of proteins. This process occurs due to the oxidative reaction between NO and a cysteine thiol group; however, the extent of this reaction remains unknown. S-Nitrosylation of PRMT1, a major asymmetric arginine methyltransferase of histones and numerous RNA metabolic proteins, was induced by NO donor treatment. We found that nitrosative stress leads to S-nitrosylation of cysteine 119, located near the active site, and attenuates the enzymatic activity of PRMT1. Interestingly, RNA sequencing analysis revealed similarities in the changes in expression elicited by NO and PRMT1 inhibitors or knockdown. A comprehensive search for PRMT1 substrates using the proximity-dependent biotin identification method highlighted many known and new substrates, including RNA-metabolizing enzymes. To validate this result, we selected the RNA helicase DDX3 and demonstrated that arginine methylation of DDX3 is induced by PRMT1 and attenuated by NO treatment. Our results suggest the existence of a novel regulatory system associated with transcription and RNA metabolism via protein S-nitrosylation.

Co-expression of DDR2 and IFITM1 promotes breast cancer cell proliferation, migration and invasion and inhibits apoptosis

PURPOSE

To investigate the roles of DDR2 and IFITM1 in breast cancer (BC).

METHODS

The expression of DDR2 and IFITM1 in BC tissues and cell lines was measured. DDR2 and/or IFITM1 were knocked down in BT20 and MDA-MB-231 cells, after which the viability, mobility and apoptosis of the cells were tested. Xenograft mouse models were established through subcutaneous tumor transplantation.

RESULTS

DDR2 and IFITM1 were highly expressed in invasive BC tissues and cell lines. Overexpression of DDR2 and/or IFITM1 was associated with poorer clinical outcomes and patient survival. Knockdown of DDR2 or IFITM1 suppressed the viability and invasiveness of BT20 and MDA-MB-231 cells and restrained the growth of xenograft tumors in nude mice. Simultaneous knockdown of IFITM1 and DDR2 surpassed knockdown of IFITM1 alone in suppressing BC development.

CONCLUSIONS

DDR2 and IFITM1 are co-expressed to facilitate the malignant behaviors of BC cells and promote the development of tumors.