Page 208 - EJMO-9-2

Eurasian Journal of
Medicine and Oncology Tetramethyl thyroxine boosts bladder cancer

Surgical resection, neoadjuvant chemotherapy, and FinnGen databases found that there was a significant
immunotherapy are common treatments for BC. Although positive correlation between thyroid cancer (THCA) and
these methods have improved survival rates to a certain BC (odds ratio = 1.140; 95% confidence interval, 1.072 –
extent, high recurrence rates and drug resistance still pose 1.212; p<0.001). Correlation analysis showed that THCA
a dilemma in the treatment of BC. The factors contributing may increase the risk of secondary BC by increasing the
to the development of cancer are numerous and complex. infiltration of N2 neutrophils. The incidence of THCA
They can be broadly categorized into two groups: internal in patients with hyperthyroidism is significantly higher
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factors, which include mutations in tumor suppressor than that in ordinary patients. A study on patients with
genes and abnormalities in the immune system, and metastatic urothelial carcinoma receiving immunotherapy
external factors, which encompass influences from the found that the group with a low free T3/free T4 ratio had
living environment and unhealthy lifestyle choices. In shorter progression-free survival and overall survival,
addition, excessive activation of hormones can also lead which was associated with a poorer prognosis. Moreover,
to tumor development. For instance, estrogen regulates this ratio was independent of other prognostic factors.
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cell growth and proliferation by binding to estrogen It indicated a relationship between thyroid hormone
receptors in breast cells, while testosterone and androgens and bladder development. However, further mechanistic
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perform a similar function by binding to androgen analysis has not been conducted. Our study aims to reveal
receptors in prostate cells. Together, these hormones the effects of T4 on BC cell proliferation, cell migration,
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regulate processes such as cell proliferation, growth, apoptosis, and tumor formation by attempting to
and metastasis. They primarily affect genes and proteins investigate its underlying mechanisms.
associated with proliferation and differentiation in cells
through their respective receptors. The main causative 2. Materials and methods
factors of BC include chronic infections, pathogens, and 2.1. Cell lines and reagents
other diseases. Furthermore, the development of BC Tetramethyl thyroxine (T4) was purchased from Shanghai
is also linked to hormonal factors, with sex hormones, Titan Technology Co., Ltd. (HPLC 98.0%, China),
particularly estrogen and progesterone, being frequently dissolved in 0.05M NaOH solution, and stored at –20°C.
reported in current literature. Croft et al. found that the We selected T4 concentrations based on prior literature
expression of the estrogen receptor ERβ is elevated in linking T4 to cancer progression and on initial pilot
BC tissues, with its expression level positively correlated experiments. Human BC cell lines (T24, CL-0227, and
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with pathological grade. Ding et al. found that estrogen EJ-1 CL-0274) were kindly provided by Procell Life Science
promotes the malignant behavior of BC by inducing and Technology Co., Ltd and were cultured in RPMI 1,640
the enhancer RNA-P2RY2e. In addition, Wolpert et al. medium (HyClone, USA) with 10% fetal bovine serum
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reported that the incidence of BC is significantly reduced (Gibco, USA) and 1% PS (Gibco, USA) at 37°C in 5% CO .
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in parous women and those taking oral contraceptives. When the cell density had been >80%, discard the culture
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However, the relationship and molecular mechanisms medium and add 1 ml of trypsin for digestion. After 2 min
linking progesterone to the development of BC remain to separate the cells from the 10 cm culture dish. The cells
unclear. were passaged at a ratio of 1:2/1:3, once every 2 – 3 days.
Thyroid hormones, which include T4 and
triiodothyronine (T3), are critical regulators of various 2.2. Cell viability by cell counting kit-8 (CCK-8) assay
physiological processes. T4 is also known as thyroxine. T24 and EJ-1 cells were inoculated at 5,000 per well in 96
Thyroid hormones exert their effects by binding to integrin plates and diluted T4 to a range of 0 – 100 nM for treatment.
receptor sites, thereby regulating the expression of target After 24 h and 48 h, drug-containing medium was aspirated.
genes. They play a significant role in activating cell growth, Subsequently, RPMI 1,640 medium containing 10% CCK-8
inhibiting apoptosis, and stimulating angiogenesis during solution was added to each well and incubated in a 5% CO
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the carcinogenesis process. Furthermore, a correlation has incubator for 2 h. We performed three biological replicates
been observed between elevated thyroid hormone levels, during the experiment. The absorbance of each well was
reduced thyroid-stimulating hormone (TSH) levels, and measured at 450 nm using a Multiskan FC microtiter plate
™
an increased risk of cancer. As a thyroid hormone, T4 instrument (Thermo Fisher Scientific, USA).
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has been shown in multiple clinical trials to be associated
with the development and poor prognosis of breast 2.3. Flow cytometry detection of cell apoptosis
cancer, prostate cancer, lung cancer, acute leukemia, and 1.5 × 10 T24 and EJ-1 cells were seeded in a 6-well plate,
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other cancers, but most of these studies stop at analyzing and cells were collected after treatment with T4 at different
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clinical data. An analysis based on the UK Biobank and concentrations (0 nM, 10 nM, 100 nM) for 48 h. Annexin

Volume 9 Issue 2 (2025) 200 doi: 10.36922/EJMO025080037