GKC helps! The team from Zhengzhou University designed aptamers for the treatment of esophageal squamous cell carcinoma and confirmed that the molecular target was integrated β1

Globally, esophageal cancer is the sixth most common cause of cancer-related death and poses a significant threat
to human health.
In 2021, more than 600,000 new cases of esophageal cancer were diagnosed worldwide
.
There are two subtypes of esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma, and ESCC accounts for about 90%
of all esophageal cancers.
Most patients diagnosed with esophageal cancer have advanced metastases, resulting in poor prognosis and high
mortality.
In clinical practice, the current treatment of esophageal cancer is mainly limited to conventional methods, including surgical resection, chemotherapy and radiotherapy
.
At present, esophageal cancer clearly lacks molecular targeted therapy
.
Therefore, there is an urgent need to develop identifying molecules and molecular targets for early diagnosis and treatment of esophageal cancer
.

The team of Yuan Baoyin and Liu Kangdong of Zhengzhou University published a report entitled "DNA Aptamer Selected against Esophageal Squamous Cell Carcinoma for Tissue Imaging and Targeted Therapy with Integrin β1 as a" in Analytical Chemistry (IF:8.
008).
Molecular Target"
.
In this study, the research team screened out aptamers that can specifically identify ESCC cell lines through Cell-SELEX technology, and proved through tissue imaging that aptamer A2 can identify esophageal squamous cell carcinoma tissue, and the team also identified the aptamer-bound target as integratin β1
through pull-down, mass spectrometry experiments (technical services provided by GK) and siRNA interference technology.
In addition, the team achieved specific killing
of target tumor cells in vitro and in vivo by constructing an A2-NA nanostructure-loaded chemotherapy drug doxorubicin (Dox).

Study results

1.
Cell-SELEX technology was used to screen aptamers that bind to nucleic acids with high affinity to target cells

The dissociation constants of A2, A3 and A4 aptamers binding to target cells are all nanomolar level, all three aptamers can bind to the cell membrane of target cells, and aptamer A2 can specifically recognize esophageal squamous cell carcinoma tissue
.

【Supplementary knowledge】:

SELEX technology is Systematic Evolution of Ligands by Exponential Enrichment (SELEX).

This technique allows the screening of aptamers (Aptamer)
with high specificity and affinity for the target substance from a random single-stranded nucleic acid sequence library.
Cell-SELEX technology is a method
of obtaining aptamers that can bind to specific target cells based on SELEX technology.

2.
The molecular target of aptamer A2 binding to target cells is integrin-β1 (Integrin β1)

Flow cytometry was used to preliminarily verify that the target of aptamer A2 binding to target cells was a protein, and the A2-binding target was further verified as Integrin β1
by pull-down experiment, mass spectrometry technology (technical services provided by GK) and gene knockdown experiment.
In addition, the specific binding site of A2 to Integrin β1 was accurately predicted by molecular docking technology
.

3.
Design A2-linked DNA nanostructures to achieve targeted delivery of chemotherapy drug Dox

Using the principle of HCR (hybrid chain reaction), the A2-linked DNA nanostructure was designed, which can load 100 times the concentration of Dox and deliver it to the target tumor cells, reducing the toxic side effects
of chemotherapy drugs.

Conclusion of the study

(1) Through Cell-SELEX, nucleic acid aptamers with high affinity and high specificity binding to poorly differentiated esophageal squamous cell KYSE410 cells were screened, among which aptamer A2 can specifically image esophageal squamous cell carcinoma tissues of patients, which is expected to be used as a specific imaging probe for the diagnosis of esophageal squamous cell carcinoma;

(2) The main target of binding aptamer A2 to target cells was identified as integrin β1, which has the potential to be used as a marker and therapeutic target for esophageal squamous cell carcinoma;

(3) A2-NA nanostructures were designed and constructed with aptamer A2 as the targeted molecule, which can load high concentrations of Dox and specifically deliver them to target cells to achieve targeted therapy
of tumors.

GKC helps

In this study, mass spectrometry was used to detect target proteins bound by aptamer A2, with technical services
provided by GK.

About the author

Yuan Baoyin