Table 1.

Types and characteristics of mRNA modifications.

	mRNA modification	Target	Application	Ref.
Pyrimidine bases	m6A	Glioblastoma	Knockdown of METTL3 or METTL14 promotes glioblastoma stem cell (GSC) self-renewal and tumorigenesis.	[46]
	m6A	Bladder cancer	METTL3 promotes cancer growth through pri-miR221/222 process in m6A-dependent manner.	[47]
	m6A	Hepatocellular carcinoma	Downregulation of METTL14 significantly promotes tumor metastasis.	[48]
	m6A	Cardiac hypertrophy	CHAPIR–METTL3–PARP10–NFATC4 signaling axis promotes cardiac hypertrophy.	[49]
	m1A	Breast and ovarian cancer cells	Up-regulation of ALKBH3 enhances the degree of CSF-1 expression and cancer cell invasion.	[56]
	m1A	Zebrafish embryos	ALKBH3 regulates the mRNA of Aurora A, a master suppressor of ciliogenesis.	[57]
	m7G	HUVEC	Improved METTL1 expression increases HUVECs migration, proliferation, and tube formation.	[65]
	m7G	Mammary epithelial cells	Cyclin D1 mRNA enhanced by RNMT regulates oncogene expression and cell transformation.	[67]
Purine bases	m5C	Human colon carcinoma cells and HeLa cells	NSUN2 enhances p21 expression and cellular oxidative stress.	[71]
	m5C	T lymphocytes	NSun2 regulates immune function by promoting the translation of IL-17A in T lymphocytes.	[73]
	Pseudouridine	Human embryonic kidney cells	mRNA with pseudouridine interacts less with PKR, resulting in reduced phosphorylation eIF-2α.	[82]
5′-cap	m7,3′-O-propargylGpppG	HeLa cells	Propargyl cap analog form a stable complex with the translation initiation factor than the standard 5′-cap, and the translation efficiency is 3.1-times higher.	[93]
	Co-transcriptional capping	Human monocytic cells and human CD34+ cells	Co-transcriptional capping increases Cas9 mRNA activity and reduces immunogenicity.	[94]
	m7(LNA)GpppAmPG	Immortalized mouse immature dendritic cells	The combination of LNA and 5′-cap has 5-times more translation efficiency than standard 5′cap	[97]
	S-Adenosyl methionine (AdoMet)	Human embryonic kidney cells and HeLa cells	AdoMet induces 3-times higher immune responses in human cells.	[98]
Poly (A) tail	5′,3′-phosphodiester bond poly (A) tail	HeLa cells	5′,3′-phosphodiester bond poly (A) tail improves translation efficiency of Gaussia luciferase mRNA and suppresses mRNA degradation.	[99]
	Azido-modified adenosine nucleotides in the poly(A) tail	HeLa cells	The covalent modification at the poly(A) tail leads to increase in translational efficiency without genetical editing.	[100]