Hath1 inhibits proliferation of colon cancer cells probably through up-regulating expression of Muc2 and p27 and down-regulating expression of cyclin D1

Atonal bHLH transcription factor 1 is an important factor for maintaining the balance of cell proliferation and differentiation in tumorigenesis

Establishing the link between cellular processes and oncogenesis may aid the elucidation of targeted and effective therapies against tumor cell proliferation and metastasis. Previous studies have investigated the mechanisms involved in maintaining the balance between cell proliferation, differentiation and migration. There is increased interest in determining the conditions that allow cancer stem cells to differentiate as well as the identification of molecules that may serve as novel drug targets. Furthermore, the study of various genes, including transcription factors, which serve a crucial role in cellular processes, may present a promising direction for future therapy. The present review described the role of the transcription factor atonal bHLH transcription factor 1 (ATOH1) in signaling pathways in tumorigenesis, particularly in cerebellar tumor medulloblastoma and colorectal cancer, where ATOH1 serves as an oncogene or tumor suppressor, respectively. Additionally, the present review summarized the associated therapeutic interventions for these two types of tumors and discussed novel clinical targets and approaches.

MicroRNA-613 promotes colon cancer cell proliferation, invasion and migration by targeting ATOH1

The aim of the present study is to investigate the expression and function of miR-613 in colon cancer (CC) and illuminate the molecular mechanisms underlying miR-613-regulated CC progression. Our data demonstrated that miR-613 was upregulated in CC tissue samples (P = 0.009) and human CC cell lines (HCT-116 and Lovo; P = 0.001 and P = 0.003, respectively), which also promoted the proliferation, invasion and migration of CC cells (P < 0.05). The dual-luciferase reporter assay confirmed that Atonal homolog1 (ATOH1) was the target mRNA of miR-613. Rescue experiments showed that ATOH1 overexpression vector significantly reversed the stimulative effects of miR-613 mimic on the progression of HCT-116 and Lovo cells (P < 0.001). Positive ATOH1 expression in CC tissues was significantly associated with lower grade (χ² = 3.592, P = 0.043), lower TNM stage (χ² = 3.537, P = 0.048) and better overall survival (P=0.041). Jun N-terminal kinase 1 (JNK1) pathway and Mucin 2 (MUC2) were the potential downstream proteins of miR-613/ATOH1. miR-613 is an oncogene in CC and promotes the proliferation, invasion and migration of CC cells by targeting ATOH1 likely via activating JNK1 pathway and upregulating MUC2.

Effect of Hath1 on the proliferation and apoptosis of cutaneous squamous cell carcinoma in vitro

Increasing evidence has demonstrated that the tumor suppressor gene Hath1 is implicated in the development and progression of tumors and is verified to be downregulated in several types of tumor. However, the roles and precise molecular mechanisms of Hath1 in cutaneous squamous cell carcinoma (SCC) remain to be elucidated. In the present study, two approaches were used to investigate the tumor-suppressing effect of Hath1 in cutaneous SCC. Firstly, the effect of inhibiting Hath1 expression with short hairpin RNA (shRNA) on tumor growth and apoptosis was investigated. KUMA5 cells were stably transfected with a plasmid expressing Hath1 shRNA (pGenesil-1-Hath1). Secondly, the anti-tumor effect of Hath1 was investigated in KUMA5 cells following transfection with pcDNA3.1-Hath1. The mRNA and protein expression of Hath1 was detected by reverse transcription quantitative polymerase chain reaction and western blot analysis, respectively. Cell proliferation in vitro was assessed using an MTT assay. Flow cytometry was used to detect cell apoptosis. The results demonstrated that compared with the control groups, the expression of Hath1 was significantly reduced in the KUMA5/pGenesil-1-Hath1 cells and markedly increased in the KUMA5/pcDNA3.1-Hath1 cells. Cell proliferation was markedly increased in the KUMA5/pGen-esil-1-Hath1 cells in a time-dependent manner; however, it was markedly inhibited in the KUMA5/pcDNA3.1-Hath1 cells. Flow cytometry revealed that apoptosis decreased in KUMA5/pGenesil-1-Hath1 cells and increased in KUMA5/pcDNA3.1-Hath1 cells. Downregulation of Hath1 expression promoted the proliferation and reduced the apoptosis of KUMA5 cells. By contrast, overexpression of Hath1 inhibited proliferation and induced the apoptosis of KUMA5 cells. These findings provide possible new strategies and therapeutic targets for the treatment and diagnosis of cutaneous SCC.