Harnessing the TP53INP1/TP53I3 axis for inhibition of colorectal cancer cell proliferation through MEG3 and Linc-ROR Co-expression.

Dysregulation of long noncoding RNAs (lncRNAs), such as maternally expressed gene 3 (MEG3) and long intergenic noncoding RNA regulator of reprogramming (linc-ROR), plays a crucial role in colorectal cancer progression. We aimed to assess linc-ROR silencing and MEG3 activation on the colorectal cancer cell proliferation simultaneously; and explore the underlying mechanisms in the TP53-associated Pathway. The MEG3 and linc-ROR shRNA were cloned under the bidirectional CEA promoter (UM1). Subsequently, additional vectors were constructed to express linc-ROR shRNA (UM2) and MEG3 (UM3). After transfecting colorectal cancer cell lines with these recombinant vectors, experiments on cell viability, apoptosis, and cell cycle analysis were conducted. Furthermore, TP53's transcriptional activity and associated genes were assessed using quantitative real-time polymerase chain reaction (qRT-PCR). Interestingly, UM1 significantly inhibited the proliferation of both cell lines than UM2 and UM3. In response to UM1, TP53 transcript remarkably increased in HCT116 cells (10.46) than SW480 cells (6.16); which resulted in up-regulation of TP53INP1, TP53I3, GDF15, CCKN1A and BAX, and down-regulation of G1 cyclins (D1, E1). The rate of apoptosis increased in HCT116 (36.35 %) and SW480 (16.64 %) cells than control. Moreover, UM1-transfected HCT116 cells exhibited a notable arrest in the G0/G1 phase, accompanied by a reduction in the G2/M cell population. Compared to unidirectional vectors, the concurrent targeting approach enhanced TP53 activation at the transcription level. The cell response to UM1 resulted in rapid upregulation of TP53, leading to inhibition of cell proliferation, increased apoptosis, and cell cycle arrest. These findings suggest that the synergistic effect of targeting both MEG3 and linc-ROR could serve as a promising therapeutic strategy for TP53-associated colon cancer.