# Feedback Modulation between Human IN080 Chromatin Remodeling Complex and miR-372 in HCT116 Cells
## 3 Discussion  
In this report, we first proposed that the INO80 complex and miR-372 are mutually regulated in HCT116 colorectal cancer cells using in vitro biological experiments combining knockdown and over-expression approaches. In a transcriptome sequencing analysis from our previous study, we found that the INO80 complex upregulated miR-372 transcription in HeLa cells. The possible reason is that the INO80 complex, as a chromatin remodeling complex, is widely involved in the transcriptional regulation of multiple genes by altering chromatin structure. Upon knocking down the INO80 complex in different types of cancer cells, the proteins (or complexes) or transcription cofactors recruited by INO80 in the pro  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Primers** & **Directions** & **Sequences** \\ \hline \(-2.5\,\mathrm{kb}\) & forward & \(\$^{\prime}\)-ACATCTTCCCAGCACATCTC.\(\ddagger\) \\ \(-2.5\,\mathrm{kb}\) & reverse & \(\$^{\prime}\)-TAGGGAATGTGGAAAAGGTG-\(\ddagger\) \\ \(-2.2\,\mathrm{kb}\) &  
more region of the miR-371-373 gene cluster may have different effects on the expression level of miR-372-373. Furthermore, according to the currently reported literature, the expression level of miR-372 varies depending on the type of cancer. For example, compared to normal tissues, miR-372-373 is significantly reduced in tissues such as non-small cell lung cancer [11], pancreatic cancer [16], cervical cancer [18], endometrial cancer [19], and ovarian cancer [20]. On the contrary, the expression of miR-372 is higher in lung squamous cell carcinoma [21], colorectal cancer [15], esophageal squamous cell carcinoma [13], and hepatocellular carcinoma [23] than in normal tissues. It is worth mentioning that in certain specific cancer types, the expression level of miR-372 contradicts the results reported by different research groups, such as breast cancer and colon cancer [25; 26]. This influence pattern was further confirmed in HCT116 cells by knocking down multi-subunits of the INO80 complex, including INO80, Arp8, Ies2, and YY1. On the other hand, by combining methods of mimic miR-372 expression and dual luciferase assays, we postulate that the role of the miR-372 in post-transcriptionally regulating the expression of the INO80 complex by targeting and binding to the complementary sequences in the 3\({}^{\prime}\)-UTR of INO80 and Arp8. In addition, we speculate that the INO80 complex and miR-372 may be involved in the p21/p53 pathway in a coordinated regulation mode. Evolutionarily conservative shared subunits of the human INO80 complex assemble on conserved ATPase and HSA domains of the INO80 catalytic protein to maintain nucleosome sliding and ATPase activity [33; 34]. Any subunit, including INO80 catalytic protein, Arp8, YY1, Ies2, Arp5, Ies6, and Tip49a/b, deficiency in the HSA and SNF2 modules may lead to the loss of function of INO80 complex, which in turn affects transcriptional gene regulation [41]. In line with this, a total of 9478 genes were differentially expressed due to knocking down _INO80_, _Arp8_, _Arp5_, _Ies6_, and _Ies2_, which are tightly related to cell proliferation, cell growth, cell adhesion, cell migration, cell motion, cell division, and cell motility, suggesting the importance of the INO80 complex in regulating basic cell biological functions. It is worth noting that miRNAs are also regarded as targets of epigenetic regulators such as DNA methyltransferases (DNMTs) and histoneacetylases (HDACs) [42]. Consistent with this view, knocking down multi-subunits (_INO80_, _Arp8_, _YY1_, _Ies2_) of the INO80 complex upregulated pri-_miR-372_ in HCT116 cells. In addition, miR-372 was also identified as one of the targets from INO80 complex knockdown of gene expression profiles. The above results suggest that miR-372 is a potential target of the INO80 complex.