Telomerase inhibition decreases esophageal squamous carcinoma cell migration and invasion

Innovating Cancer Treatment Through Cell Cycle, Telomerase, Angiogenesis, and Metastasis

Cancer remains a formidable challenge in the field of medicine, necessitating innovative therapeutic strategies to combat its relentless progression. The cell cycle, a tightly regulated process governing cell growth and division, plays a pivotal role in cancer development. Dysregulation of the cell cycle allows cancer cells to proliferate uncontrollably. Therapeutic interventions designed to disrupt the cell cycle offer promise in restraining tumor growth and progression. Telomerase, an enzyme responsible for maintaining telomere length, is often overactive in cancer cells, conferring them with immortality. Targeting telomerase presents an opportunity to limit the replicative potential of cancer cells and hinder tumor growth. Angiogenesis, the formation of new blood vessels, is essential for tumor growth and metastasis. Strategies aimed at inhibiting angiogenesis seek to deprive tumors of their vital blood supply, thereby impeding their progression. Metastasis, the spread of cancer cells from the primary tumor to distant sites, is a major challenge in cancer therapy. Research efforts are focused on understanding the underlying mechanisms of metastasis and developing interventions to disrupt this deadly process. This review provides a glimpse into the multifaceted approach to cancer therapy, addressing critical aspects of cancer biology-cell cycle regulation, telomerase activity, angiogenesis, and metastasis. Through ongoing research and innovative strategies, the field of oncology continues to advance, offering new hope for improved treatment outcomes and enhanced quality of life for cancer patients.

Comparative Analysis of Primary Ovarian Cancer Cells and Established Cell Lines as a New Tool for Studies on Ovarian Cancer Cell Complexity

Primary cancer cells reflect the genetic background and phenotype of a tumor. Immortalized cells with higher proliferation activity have an advantage over primary cells. The aim of the study was to immortalize the primary ovarian cancer (OvCa) cells using the plasmid-carrying human telomerase reverse transcriptase (hTERT) gene and compare their phenotype and biological activity with the primary cells. The primary OvCa3 A and OvCa7 A cells were isolated from the ascitic fluid of two high-grade serous ovarian cancer patients and were characterized using immunocytochemical methods, flow cytometry, real-time RT-PCR, Western blot, metabolic activity, and migratory potential. Both immortalized ovarian cancer cell lines mirrored the phenotype of primary cancer cells, albeit with modifications. The OvCa3 A hTERT cells kept the mesenchymal stem cell phenotype of CD73/CD90/CD105-positivity and were CD133-negative, whereas the cell population of OvCa7 A hTERT lost CD73 expression, but almost 90% of cells expressed the CD133 characteristic for the CSCs phenotype. Immortalized OvCa cells differed in gene expression level with respect to Sox2 and Oct4, which was associated with stemness properties. The OvCa7 A hTERT cells showed higher metabolic and migratory activity and ALDH1 expression than the corresponding primary OvCa cells. Both primary and immortalized cell lines were able to form spheroids. The newly established unique immortalized cell line OvCa7 A hTERT, with the characteristic of a serous ovarian cancer malignancy feature, and with the accumulation of the p53, Pax8, and overexpression of the CD133 and CD44 molecules, may be a useful tool for research on therapeutic approaches, especially those targeting CSCs in ovarian cancer and in preclinical 2D and 3D models.

BIBR1532 inhibits proliferation and enhances apoptosis in multiple myeloma cells by reducing telomerase activity

Background

Multiple myeloma (MM) is a rare haematological disorder with few therapeutic options. BIBR1532, a telomerase inhibitor, is widely used in cancer treatment and has promising outcomes. In this study, we investigated the efficacy and mechanism of action of BIBR1532 in MM.

Methods

K562 and MEG-01 cells were cultured with BIBR1532 at different concentrations. After 24 and 48 h, cell survival was analyzed. Next, these cells were cultured with 25 and 50 µM BIBR1532 for 48 h, then, cell proliferation, apoptosis, and the expression of the telomerase activity related markers were tested by 5-Ethynyl-2'-deoxyuridine (EdU) staining, flow cytometric analysis, western blot and quantitative real-time PCR (qRT-PCR), respectively. Expression of Bcl-xL, Bad, Survivin, phosphorylation of PI3K, AKT, mTOR, ERK1/2, and MAPK were tested via western blotting. Further experiments were conducted to evaluate the synergistic effects of BIBR1532 and doxorubicin (Dox) or bortezomib (Bor).

Results

BIBR1532 inhibited K562 and MEG-01 cell survival in a dose- and time-dependent manner. In addition, BIBR1532 hindered cell proliferation while promoting apoptosis, and this effect was enhanced by increasing the BIBR1532 concentration. Moreover, BIBR1532 inhibited TERT and c-MYC expression, PI3K, AKT, mTOR phosphorylation, and facilitated ERK1/2 and MAPK phosphorylation. Additionally, BIBR1532 combined with Dox or Bor showed synergistic effects in MM treatment.

Conclusion

BIBR1532 inhibits proliferation and promotes apoptosis in MM cells by inhibiting telomerase activity. Additionally, BIBR1532 combined with Dox or Bor exhibited synergistic effects, indicating that BIBR1532 may be a novel medicine for the treatment of MM.

Human Telomerase Reverse Transcriptase as a Therapeutic Target of Dihydroartemisinin for Esophageal Squamous Cancer

Objective: To elucidate the oncogenic role of human telomerase reverse transcriptase (hTERT) in esophageal squamous cancer and unravel the therapeutic role and molecular mechanism of dihydroartemisinin (DHA) by targeting hTERT. Methods: The expression of hTERT in esophageal squamous cancer and the patients prognosis were analyzed by bioinformatic analysis from TCGA database, and further validated with esophageal squamous cancer tissues in our cohort. The Cell Counting Kit-8 (CCK8) and colony formation assay were used to evaluate the proliferation of esophageal squamous cancer cell lines (Eca109, KYSE150, and TE1) after hTERT overexpression or treated with indicated concentrations of DHA. Transwell migration assay and scratch assay were employed to determine the migration abilities of cancer cells. Fluorescence microscopy and flow cytometry were conducted to measure the intracellular reactive oxygen species (ROS) levels in cancer cells after treated with DHA. Moreover, RT-PCR and Western blot were performed to test the alteration of associated genes on mRNA and protein level in DHA treated esophageal squamous cancer cell lines, respectively. Furthermore, tumor-bearing nude mice were employed to evaluate the anticancer effect of DHA in vivo. Results: We found that hTERT was significantly upregulated in esophageal squamous cancer both from TCGA database and our cohort also. Overexpression of hTERT evidently promoted the proliferation and migration of esophageal squamous cancer cells in vitro. Moreover, DHA could significantly inhibit the proliferation and migration of esophageal cancer cell lines Eca109, KYSE150, and TE1 in vitro, and significantly down-regulate the expression of hTERT on both mRNA and protein level in a time- and dose-dependent manner as well. Further studies showed that DHA could induce intracellular ROS production in esophageal cancer cells and down-regulate SP1 expression, a transcription factor that bound to the promoter region of hTERT gene. Moreover, overexpression of SP1 evidently promoted the proliferation and migration of Eca109 and TE1 cells. Intriguingly, rescue experiments showed that inhibiting ROS by NAC alleviated the downregulation of SP1 and hTERT in cells treated with DHA. Furthermore, overexpression of SP1 or hTERT could attenuate the inhibition effect of DHA on the proliferation and migration of Eca109 cells. In tumor-bearing nude mice model, DHA significantly inhibited the growth of esophageal squamous cancer xenografts, and downregulated the expression of SP1 and hTERT protein, while no side effects were observed from heart, kidney, liver, and lung tissues by HE stain. Conclusion: hTERT plays an oncogenic role in esophageal squamous cancer and might be a therapeutic target of DHA through regulating ROS/SP1 pathway.