RRS1 (human regulator of ribosome synthesis 1), an essential nuclear protein involved in ribosome biogenesis, is overexpressed in some human cancers, yet its role in breast cancer remains unclear. Here, we report a functional analysis of RRS1 in breast cancer and its likely mechanism. Immunohistochemistry (IHC) and RT‐qPCR analyses indicated that RRS1 was commonly overexpressed in breast cancer tissues. The copy numbers of RRS1 were higher in tumours compared with those for normal tissues. And there was a significant correlation between copy number and mRNA expression. In addition, RRS1 overexpression was significantly correlated with lymph node metastasis and poor survival. RRS1 mRNA and protein levels were also significantly increased in a panel of human breast cancer cell lines. RRS1 knockdown inhibited proliferation and induced apoptosis and cell cycle arrest in all three cell lines. Furthermore, RRS1 knockdown suppressed the tumour formation and growth of MDA‐MB‐231 cells in nude mice. Additionally, RRS1 knockdown activated p53 and p21 in MCF‐7 cells. A marked increase in the quantity of ribosome‐free RPL11 was detected by Western blot. Moreover, co‐immunoprecipitation (CoIP) experiments showed that RRS1 knockdown activated p53 by facilitating the direct contact of MDM2 and RPL11/RPL5. Taken together, our results suggest that RRS1 may contribute to breast cancer proliferation through RPL11/MDM2‐mediated p53 activation. Therefore, RRS1 may be a promising target for breast cancer therapy.
Neuroblastoma (NB) is considered a highly prevalent extracranial solid tumor in young children, and the upregulation of N-myc proto-oncogene (MYCN) is closely associated with the late stages of NB and poor prognostic outcomes. The current study was designed to evaluate the effects of exosomal microRNA (miRNA/miR)-17-5p from MYCN-amplified NB cells on the proliferative and migratory potential of non-MYCN amplified NB cells. miR-17-5p was found to activate the PI3K/Akt signaling cascade by targeting PTEN, and the overexpression of miR-17-5p was found to promote cellular migration and proliferation
in vitro
. Further experimentation revealed that the elevated expression of miR-17-5p in SK-N-BE(2) cell-derived exosomes significantly promoted the proliferative and migratory capacities of SH-SY5Y cells by inhibiting PTEN. Collectively, these findings demonstrated that miR-17-5p derived from MYCN-amplified NB cell exosomes promoted the migration and proliferation of non-MYCN amplified cells, highlighting an exosome-associated malignant role for miR-17-5p.
Since malachite green was banned for using in food fish due to its carcinogenic and teratogenic effects on human, the search of alternative drug to treat Ichthyophthirius multifiliis becomes urgent. This study aimed to (1) evaluate the ethanol extracts of medicinal plants Cynanchum atratum, Zingiber officinale, Cynanchum paniculatum, immunostimulant (A), and immunostimulant (B) for their efficacy against I. multifiliis, and (2) determine effects of medicated feeds with C. atratum, Z. officinale, C. paniculatum, and immunostimulant (A) to treat I. multifiliis in grass carp. The results in this study showed that the minimum concentrations of C. atratum, Z. officinale, and C. paniculatum extracts for killing all theronts were 16, 8, and 16 mg/L, respectively. In vivo experiments, fish fed with medicated feeds of C. atratum for 10 days, or Z. officinale for 3 days, or combination of three plants for 10 days resulted in a significant reduction in the I. multifiliis infective intensity on grass carp after theronts exposure. Grass carp fed with medicated feeds of immunostimulant (A) for 21 days showed no infection and 100 % of survival 15 days post theronts exposure. Therefore, immunostimulant (A) is a promising feed supplement to treated I. multifiliis with good antiparasitic efficacy.
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