bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/640508

PITX1 protein interacts with ZCCHC10 to regulate hTERT mRNA transcription

Ohira, T.·Kojima, H.·Kuroda, Y.·Inaoka, D.·Osaki, M.·Wanibuchi, H.·Okada, F.·Oshimura, M.·Kugoh, H.
View original source ↗Export metadata ↓

Abstract

Telomerase is a ribonucleoprotein ribonucleic enzyme that is essential for cellular immortalization via elongation of telomere repeat sequences at the end of chromosomes. Human telomerase reverse transcriptase (hTERT), the catalytic subunit of telomerase holoenzyme, is a key regulator of telomerase activity. Telomerase activity, which has been detected in the majority of cancer cells, is accompanied by hTERT expression, resulting in continuous cell division that is a crucial factor for malignant transformation. Thus, hTERT is an attractive target for cancer-specific treatments. We previously reported that pared-like homeodomain 1 (PITX1) is a negative regulator of hTERT through direct binding to the hTERT promoter. However, the mechanism by which the function of PITX1 contributes to transcriptional silencing of the hTERT gene remains to be clarified. Here, we show that PITX1 and zinc finger CCHC-type containing 10 (ZCCHC10) proteins cooperate to facilitate the transcriptional regulation of the hTERT gene by functional studies via FLAG pull-down assay. Co-expression of PITX1 and ZCCHC10 resulted in inhibition of hTERT transcription, in melanoma cell lines, whereas mutate-deletion of homeodomain in PITX1 that interact with ZCCHC10 did not induce similar phenotypes. In addition, ZCCHC10 expression levels showed marked decrease in the majority of melanoma cell lines and tissues. Taken together, these results suggest that ZCCHC10-PITX1 complex is a new functional unit that suppresses hTERT transcription, and plays a crucial role in cancer development through regulation of telomerase activity.

Source connections

Explore related subjects

cancer biologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Ohira, T., Kojima, H., Kuroda, Y., Inaoka, D., Osaki, M., Wanibuchi, H., Okada, F., Oshimura, M., Kugoh, H.. 2019-05-16. PITX1 protein interacts with ZCCHC10 to regulate hTERT mRNA transcription. https://doi.org/10.1101/640508

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Arrest-associated transcriptional programmes outweigh apoptosis-associated programmes in treatment-naive pancreatic ductal adenocarcinoma

Background: Pancreatic ductal adenocarcinoma (PDAC) is driven by mutant KRAS, and RAS inhibitors now extend survival in previously treated metastatic disease. Whether treatment shrinks a tumour or only halts its growth depends partly on whether cancer cells die or stop dividing, yet how untreated PDAC cells are balanced between these programmes is unknown. Aims: We aimed to characterise the balance between apoptosis-associated and arrest-associated transcriptional programmes in treatment-naive PDAC and to examine their relationships with tumour subtype, TGM2 expression, tissue organisation, survival and drug sensitivity. Methods and results: We scored 52,999 malignant cells from 18 untreated patients in the Hwang atlas using a transcriptional contrast between genes associated with apoptosis and genes associated with resistance to apoptosis or cell-cycle arrest. In every patient the contrast was shifted toward the arrest-associated side: using equality between the two sides as the dividing threshold, 86.3% of cells with an informative score fell on that side, although the proportion depends on the threshold chosen. The shift recurred in the independent Steele atlas (median 71.6% per sample, range 37.1% to 90.8%). In the discovery cohort, tumours with higher basal-like scores had fewer arrest-side cells, and TGM2 expression was modestly higher on the arrest-associated side in both cohorts. The contrast did not track cell-line drug sensitivity or survival in bulk tumours. Conclusion: Untreated PDAC cells show a reproducible transcriptional bias toward anti-apoptotic and cell-cycle-arrest programmes. Whether this bias predicts cellular responses to treatment remains to be tested.

cancer biology↗
bioRxiv2026

Quantitative live imaging reveals region-dependent medulloblastoma disseminationin the zebrafish brain

Medulloblastoma is the most common malignant pediatric brain tumor, and relapse is frequently driven by dissemination within the central nervous system. Yet the early dynamics of tumor spread remain difficult to resolve in vivo. Here, we orthotopically transplanted human medulloblastoma cells into larval zebrafish and followed individual xenografts by longitudinal high-resolution confocal imaging. ONS-76 showed particularly robust dissemination, with hindbrain tumors spreading into the developing cerebellum in 81.5% of larvae, more than fourfold the frequency observed for forebrain or midbrain tumors. Disseminating cells extended along brain-surface and leptomeningeal-like regions and frequently associated with cerebral vasculature. Quantitative analysis of tumor area, perimeter, compactness, convex hull area, and fractal dimension captured changes in growth and spatial complexity over time. Dasatinib reduced tumor expansion and dissemination-related features in a concentration-dependent manner, while higher doses revealed host toxicity. These findings establish a powerful in vivo model for resolving medulloblastoma dissemination and therapeutic response.

cancer biology↗
bioRxiv2026

Targeting REV1 Exposes Context-Dependent Therapeutic Responses in Colorectal Cancer

Translesion synthesis (TLS) promotes DNA damage tolerance and contributes to chemotherapy resistance by enabling replication across damaged DNA templates. REV1, a central TLS regulator, is a potential therapeutic target to enhance the efficacy of genotoxic chemotherapy. Here, we investigated the therapeutic consequences of pharmacologic and genetic REV1 targeting in colorectal cancer (CRC) and evaluated the sensitivity of patient-derived CRC organoids to the REV1 inhibitor JH-RE-06. JH-RE-06 enhanced oxaliplatin sensitivity in HCT116 cells and 5-fluorouracil (5-FU) sensitivity in HT-29 cells, whereas reciprocal combinations produced limited sensitization, indicating treatment- and cellular context-dependent responses. siRNA-mediated REV1 depletion similarly enhanced chemotherapy sensitivity, supporting REV1 involvement in these responses. MNNG sensitivity assays and MLH1 expression analyses did not reveal consistent treatment-associated changes in mismatch repair function, while targeted HPRT1 sequencing identified no detectable sequence alterations in the region examined. Chemosensitization was not accompanied by consistent increases in caspase-3/7 activation under the conditions tested. REV1 inhibition also caused LC3-II accumulation and, after prolonged inhibitor exposure, reduced beta-tubulin abundance, indicating additional autophagy-associated and cytoskeletal responses. In two patient-derived CRC organoid models, JH-RE-06 exhibited single-agent growth-inhibitory activity, with mean IC50 values of 2.01 micromolar and 1.4 micromolar, respectively. Together, these findings demonstrate context-dependent chemosensitization and organoid growth inhibition following REV1 targeting, suggesting that its therapeutic consequences may extend beyond canonical TLS-mediated DNA damage tolerance.

cancer biology↗