LncRNA PAPAS may promote triple-negative breast cancer by downregulating miR-34a

Objective

To investigate the role of promoter and pre-rRNA antisense (PAPAS) long noncoding (Lnc) RNA in cancer biology.

Methods

Tumour and tumour-adjacent healthy tissue biopsies from patients with triple-negative breast cancer (TNBC), and plasma samples from these patients plus healthy controls, were assessed for PAPAS and microRNA (miR)-34a. Effects of PAPAS and miR-34a overexpression were also investigated in vitro.

Results

PAPAS was upregulated in tumour tissues of patients with TNBC versus tumour-adjacent healthy tissues. Plasma PAPAS levels were also upregulated in patients with TNBC versus healthy controls. Levels of PAPAS in tumour tissue was significantly positively correlated with PAPAS levels in plasma from patients with TNBC. MiR-34a was downregulated in tumour tissues versus adjacent healthy tissues, and was significantly correlated with PAPAS in tumour tissues. PAPAS overexpression in vitro was associated with miR-34a inhibition, while miR-34a failed to significantly affect PAPAS levels. PAPAS overexpression promoted in vitro migration and invasion of TNBC cells, while miR-34a overexpression was inhibitory. MiR-34a overexpression decreased the enhanced cell migration and invasion associated with PAPAS overexpression. PAPAS overexpression showed no significant effects on cancer-cell proliferation.

Conclusion

LncRNA PAPAS may promote TNBC by downregulating miR-34a.

LncRNA PAPAS promotes hepatocellular carcinoma by interacting with miR-188-5p

It has been observed that long noncoding RNA (lncRNA) PAPAS regulates rRNA synthesis, but its role in human diseases is unclear. Our study was carried out to investigate the role of PAPAS in hepatocellular carcinoma (HCC). In the present study, we found that PAPAS was upregulated both in plasma from patients with HCC and tumors compared with plasma from healthy people and tumor-adjacent healthy tissues. Expression levels of PAPAS in tumor tissues and plasma of patients with HCC were significantly and positively correlated. Plasma levels of PAPAS effectively distinguished stage I patients from healthy controls. MicroRNA (miR)-188-5p was downregulated in tumor tissues than in tumor-adjacent healthy tissues of patients with HCC, and was inversely correlated with PAPAS in tumor tissues but not in adjacent healthy tissues. PAPAS and miR-188-5p downregulated each other. PAPAS overexpression promoted, while miR-188-5p overexpression inhibited the HCC cell proliferation. Rescue experiment showed that miR-34a overexpression attenuated the effects of PAPAS overexpression. However, PAPAS overexpression failed to affect significantly cancer cell migration and invasion. Therefore, lncRNA PAPAS promotes HCC by interacting with miR-188-5p.