Histone Lysine Methyltransferase Wolf-Hirschhorn Syndrome Candidate 1 Is Involved in Human Carcinogenesis through Regulation of the Wnt Pathway

Abstract

A number of histone methyltransferases have been identified and biochemically characterized, but the pathologic roles of their dysfunction in human diseases like cancer are not well understood. Here, we demonstrate that Wolf-Hirschhorn syndrome candidate 1 (WHSC1) plays important roles in human carcinogenesis. Transcriptional levels of this gene are significantly elevated in various types of cancer including bladder and lung cancers. Immunohistochemical analysis using a number of clinical tissues confirmed significant up-regulation of WHSC1 expression in bladder and lung cancer cells at the protein level. Treatment of cancer cell lines with small interfering RNA targeting WHSC1 significantly knocked down its expression and resulted in the suppression of proliferation. Cell cycle analysis by flow cytometry indicated that knockdown of WHSC1 decreased the cell population of cancer cells at the S phase while increasing that at the G(2)/M phase. WHSC1 interacts with some proteins related to the WNT pathway including β-catenin and transcriptionally regulates CCND1, the target gene of the β-catenin/Tcf-4 complex, through histone H3 at lysine 36 trimethylation. This is a novel mechanism for WNT pathway dysregulation in human carcinogenesis, mediated by the epigenetic regulation of histone H3. Because expression levels of WHSC1 are significantly low in most normal tissue types, it should be feasible to develop specific and selective inhibitors targeting the enzyme as antitumor agents that have a minimal risk of adverse reaction.

In vitro histone lysine methylation by NSD1, NSD2/MMSET/WHSC1, and NSD3/WHSC1L

“…Nonetheless, our assays indicate that, in vitro, the binding of either H3 or H4 histone triggers the opening of NSD-CD. The binding cavity appears to equally accommodate the 7-mer histone peptides tested (H3K4 a.a. 1-7; H3K9 a.a. 5-11; H3K27 a.a. 23-29; H3K36 a.a. 32-38; H3K79 a.a. 75-81; H4K20 a.a. [16][17][18][19][20][21][22], likely due to all being electrostatically positively charged and presenting homologous steric hindrance. In the case of NSD2, the binding of the H4K20 peptide is favorable and stabilized by an extensive network of hydrogen bonds.…”

“…As a step forward towards understanding the molecular details of substrate recognition by NSD-CDs, we used MD simulations to examine the binding characteristics of H3K4, H3K9, H3K27, H3K36, H3K79, and H4K20 peptides. Overall, our data indicate that all the histone H3 and H4 peptides tested (H3K4 a.a. 1-7; H3K9 a.a. 5-11; H3K27 a.a. 23-29; H3K36 a.a. 32-38; H3K79 a.a. 75-81; H4K20 a.a. [16][17][18][19][20][21][22] share similar steric hindrance and have similar positive charges related to their electric field and molecular surface. These properties imply favourable binding energies for the NSD-CDs (Table 1).…”

“…H3K79 (a.a. 75-81) peptide is stabilized by hydrogen bonds with Ile1994, Phe1997, Arg2018, Met2020, Thr2030, Lys2032, Cys2063, Asn2960, Asn2066 and Thr2069 in NSD1, with Trp1074, Ala1108, His1109, Ile1113, Thr1114, His1115, Phe1116, Phe1138, Met1139, Asn1140, Thr1149, Asn1179, Leu1180, Leu1183, Asn1185, and Arg1191 in NSD2, and with Asn1197, Phe1198, Met1200, Arg1219, Met1221, Thr1231, Lys1233, Tyr1260, Cys1264, Asn1267 and Thr1270 in NSD3. H4K20 (a.a. [16][17][18][19][20][21][22] peptide is stabilized by hydrogen bonds with Trp1955, Ile1994, Thr1995, Phe1997, Arg2018, Met2020, Tyr2059, Leu2061, Glu2062, Cys2063, Asn2066 and Thr2069 in NSD1, with Ala1108, Asn1111, Ile1113, Thr1114, Phe1116, Met1118, Arg1137, Met1139, Asn1140, Tyr1178, Asp1181, Cys1182, Asn1185 and Thr1188 in NSD2, and with Val1195, Thr1196, Asn1197, Phe1198, Arg1219, Met1221, Asn1222, Tyr1260, Asp1263, Asn1267 and Thr1270 in NSD3.…”

“…Increased NSD2 activity is also reported during tumor proliferation in glioblastoma and myeloma [34], resulting in aberrantly high global levels of H3K36me2 [18]. NSD3 is amplified in primary breast carcinoma, bladder cancer, lung cancer, and liver cancer [12,16,25,35]. Abnormal fusion proteins containing NSD family members, including NSD1-NUP98 and NSD3-NUP98 fusions, increase H3K36 methylation, leading to acute myeloid leukemia [24][25][26][27][28].…”

“…The NSD proteins are oncogenes highly expressed in numerous pathological conditions and are considered attractive novel therapeutic targets in cancers [2,[9][10][11][12][13][14][15][16][17][18][19][20]. The amplification of NSD1 has been reported in multiple myeloma, lung cancer, neuroblastoma and glioblastoma.…”