KONG SAR – Media OutReach – 18 January
2022 – A study led by Hong Kong Baptist University (HKBU) has revealed that
different degrees of exposure to bisphenol S (BPS), an industrial chemical
widely used in paper products and plastic containers, are associated with the
growth and deterioration of breast tumours in a mouse model. The research
results suggest the need for more in-depth and comprehensive research on the
potential negative impact of BPS on human health, and the ongoing search for a
safer alternative for use in industrial production may be warranted.
A research team led by
Professor Cai Zongwei, Chair Professor of the Department of Chemistry
and Director of the State Key Laboratory of Environmental and Biological
Analysis at HKBU, has revealed that different degrees
of exposure to bisphenol S are associated with the growth and deterioration of
breast tumours in a mouse model.
from the HKBU scientists, the research team also included researchers from the
Shenzhen Institute of Advanced Technology at the Chinese Academy of Sciences
and Xi’an Jiaotong University. The research results have been published in the Journal
of Hazardous Materials, an international scientific journal.
Association between BPS and breast cancer
the past, bisphenol A (BPA) was widely used in the production of a diverse
range of products, such as baby bottles, food and beverage containers, and the
thermal paper used for printing receipts. As previous research has shown an
association between BPA exposure and human endocrine system disruption, metabolic
disease and an increased risk of breast cancer in recent years, scientists have
looked for alternatives to BPA, and BPS has been used as one of the
substitutes. Despite reports on the adverse effects of BPS on human health, its
impact on tumour progression and how it disrupts the relevant metabolic
processes in breast cancer remain poorly understood.
research team led by Professor Cai
Zongwei, Chair Professor of the Department of Chemistry and Director of the
State Key Laboratory of Environmental and Biological Analysis at HKBU,
carried out several experiments to explore how BPS exposure at environmentally
relevant levels affects the development of breast tumours, including the
tumour’s morphological characteristics as well as lipid and protein
distribution, with the aid of mass spectrometry imaging technology.
exposure increases tumour volume and weight
research team conducted experiments on three groups of mice model that had been
transplanted with human breast cancer cells. In the first dosing group (BPS-10
group), the mice were fed daily with a lower dosage of 10 micrograms of BPS per
kilogram of body weight for eight weeks. In the second group (BPS-100 group),
the mice were fed with a higher dosage of 100 micrograms of BPS per kilogram of
body weight. The mice in the control group were fed olive oil.
proliferation in the mice was then investigated, and the team used
morphological analysis to study the breast tumour tissue. In general, increases
in tumour volume and weight represent proliferation of tumour tissues. When a
tumour further develops, the condition of its necrotic region and its
peripheral tissues will change. However, the volume and weight of the tumour
may reduce as a result of changes in the conditions of the tissues.
the eight-week experiment, the average volume and weight of the tumours in the
BPS-10 group were 13 times and 11 times higher than that of the control group
respectively, and the average volume and weight of the tumours in the BPS-100
group were 4 times and 4.5 times higher than that of the control group
respectively. Therefore, the results show that exposure to BPS was closely related to the proliferation and
deterioration of breast tumours.
Different dosages associated with tumour
proliferation and deterioration
The research team analysed the necrotic
region and neoplastic region of the breast tumours in the three groups of mice.
The two regions are common pathological features of solid tumours. An increase
in the relative proportion of the necrotic region reflects the proliferation of
the tumour, while an extended neoplastic region indicates the deterioration of
the control group, the status of tumour cells in the necrotic region and the
neoplastic region was stable, and the mice from the group showed no significant
tumour proliferation and deterioration after the experimental period. However, in the two BPS treated groups, an increase
in tumour size was observed along with changes in the arrangement and
distribution of tumour cells conducive to tumour proliferation and
the experiment, the necrotic regions in the BPS-10 and the BPS-100 groups
accounted for 54.7% and 11.5% of the average section area of the tumours
respectively. The results indicate that a
low dosage of BPS induces faster tumour growth, and a high dosage of BPS may ultimately lead to deterioration of the tumour,
as shown by the relatively small average size of the necrotic region and the
extended neoplastic tissue in the BPS-100 group.
BPS affects the distribution of tumour-related
lipids and proteins
research team identified six lipid biomarkers that regulate tumour growth. With
the analysis of tumour tissues’ morphological characteristics and the use of
mass spectrometry imaging, it was found that in the two BPS-exposed groups,
these lipids were highly abundant in the necrotic regions of breast tumours
when compared with the control group. The team inferred that the metabolism of these tumour-regulating
lipids was interrupted in the breast tumours following exposure to BPS.
team also discovered the distribution of twelve protein biomarkers, including
the proteins associated with breast tumour proliferation and deterioration. The results demonstrate the important
function of BPS exposure-related lipids and proteins, and future research will
further explore their role in breast cancer.
BPS may increase human breast cancer risk
research team then compared the distribution of lipids and proteins in the
BPS-exposed mice groups with those observed in human breast cancer tissue
samples, and similar patterns were identified. While not all tumours will
become cancerous, based on the benchmark results, the team deduced that exposure to BPS will increase the risk of breast
cancer in humans.
was replaced by the less studied chemical BPS in industrial production. Our
research findings show that BPS may potentially be associated with breast tumour proliferation, and
further study is deemed necessary to unveil more about the chemical’s possible
negative impact on human health. In the long run, industry may need to identify
safer substitutes for both BPA and BPS. Policymakers should also establish
relevant safety standards and regulations for the use of BPS,” said