436
H. Jin
Epithelial cell adhesion molecule (EpCAM) is a transmembrane glycoprotein that
is overexpressed in many kinds of carcinoma cells even cancer stem cells [198, 199].
EpCAM expresses differently between normal and cancer cells, and it played a vital
role in tumorigenesis and tumor development. Therefore, targeting EpCAM may
provide an approach for treating colon cancer.
Survivin is an overexpressed molecular known to be associated with drug resistance, tumor aggressiveness, and poor prognosis, especially after chemotherapy and
radiotherapy. AlShamaileh et al. [200] applied EpCAM aptamer to introduce survivin
RNAi to downregulate survivin in colorectal cancer cells in vitro, and the aptamer also
inhibits tumor growth and improves the survival of mice bearing xenograft colorectal
cancer. This system can further enhance the sensitivity of colorectal cancer stem cells
towards traditional chemical drugs such as 5-FU or oxaliplatin.
Mashreghi et al. [201] conjugates the EpCAM aptamer with Doxorubicin (DOX)
liposome, this complex can effectively introduce DOX into the colon cancer C26 cells
in vitro and enhance the accumulation of DOX in xenograft tumor, hence improve
the survival rate of mice bearing C26 colon carcinoma.
Zhao et al. [202] also constructed EpCAM aptamer-conjugated cationic liposomebased nanoparticles to introduce miR-139-5p, a tumor suppressor gene, to exert a
tumor-suppressing effect on colon cancer HCT8 cells, and the CRC model also shows
tumor-targeting activity and antitumor ability of the complex in vivo.
Despite EpCAM aptamer, Kim et al. [203] conjugate AS1411 aptamer with miR221 MB-conjugated nanoparticles to develop a cancer-targeting theranostic probe.
This probe can simultaneously target cancers, image miRNA-221 biogenesis, and
inhibit miRNA-221 function in colon adenocarcinoma Caco-2 and CT26 cells.
Besidesaptamer-based target therapy, there are also excellent works on early
detection of CRC.
CEA is the first blood biomarker used for CRC detection and is the first prognostic
indicator of disease recurrence in CRC patients [204]. Pan et al. [64] reported an
aptamer-based microchip capillary electrophoresis (MCE) in conjunction with laserinduced fluorescence (LIF) detection system to detect CEA in serum samples from
CRC patients and healthy subjects. This aptamer has a LOD of 68 pg mL
−1 with
a linear range of 130 pg mL
−1 –8 ng mL
−1 , the concentration of CEA detected in
the serum of patients and healthy subjects was 42.38 ng mL
−1 and 2.22 ng mL
−1 ,
respectively. Consistent with the results of Enzyme-Linked Immunosorbent Assay
(ELISA), the aptamer makes it possible to further develop a practical device in clinical
diagnosis, prognosis, and monitoring of cancer progression in CRC.
These findings indicate that an aptamer-based system has the potential to be used
in clinical settings and opens a new avenue to improve diagnosis and treatment
outcomes in oncologic clinics.
H. Jin
Epithelial cell adhesion molecule (EpCAM) is a transmembrane glycoprotein that
is overexpressed in many kinds of carcinoma cells even cancer stem cells [198, 199].
EpCAM expresses differently between normal and cancer cells, and it played a vital
role in tumorigenesis and tumor development. Therefore, targeting EpCAM may
provide an approach for treating colon cancer.
Survivin is an overexpressed molecular known to be associated with drug resistance, tumor aggressiveness, and poor prognosis, especially after chemotherapy and
radiotherapy. AlShamaileh et al. [200] applied EpCAM aptamer to introduce survivin
RNAi to downregulate survivin in colorectal cancer cells in vitro, and the aptamer also
inhibits tumor growth and improves the survival of mice bearing xenograft colorectal
cancer. This system can further enhance the sensitivity of colorectal cancer stem cells
towards traditional chemical drugs such as 5-FU or oxaliplatin.
Mashreghi et al. [201] conjugates the EpCAM aptamer with Doxorubicin (DOX)
liposome, this complex can effectively introduce DOX into the colon cancer C26 cells
in vitro and enhance the accumulation of DOX in xenograft tumor, hence improve
the survival rate of mice bearing C26 colon carcinoma.
Zhao et al. [202] also constructed EpCAM aptamer-conjugated cationic liposomebased nanoparticles to introduce miR-139-5p, a tumor suppressor gene, to exert a
tumor-suppressing effect on colon cancer HCT8 cells, and the CRC model also shows
tumor-targeting activity and antitumor ability of the complex in vivo.
Despite EpCAM aptamer, Kim et al. [203] conjugate AS1411 aptamer with miR221 MB-conjugated nanoparticles to develop a cancer-targeting theranostic probe.
This probe can simultaneously target cancers, image miRNA-221 biogenesis, and
inhibit miRNA-221 function in colon adenocarcinoma Caco-2 and CT26 cells.
Besidesaptamer-based target therapy, there are also excellent works on early
detection of CRC.
CEA is the first blood biomarker used for CRC detection and is the first prognostic
indicator of disease recurrence in CRC patients [204]. Pan et al. [64] reported an
aptamer-based microchip capillary electrophoresis (MCE) in conjunction with laserinduced fluorescence (LIF) detection system to detect CEA in serum samples from
CRC patients and healthy subjects. This aptamer has a LOD of 68 pg mL
−1 with
a linear range of 130 pg mL
−1 –8 ng mL
−1 , the concentration of CEA detected in
the serum of patients and healthy subjects was 42.38 ng mL
−1 and 2.22 ng mL
−1 ,
respectively. Consistent with the results of Enzyme-Linked Immunosorbent Assay
(ELISA), the aptamer makes it possible to further develop a practical device in clinical
diagnosis, prognosis, and monitoring of cancer progression in CRC.
These findings indicate that an aptamer-based system has the potential to be used
in clinical settings and opens a new avenue to improve diagnosis and treatment
outcomes in oncologic clinics.