Zhongguo aizheng zazhi (Jan 2022)
Correlations between expressions of DPD, LC3 and P62 in colorectal cancer and their clinical significance
Abstract
Background and purpose: Colorectal cancer is one of the most common malignancies. The efficacy of 5-fluorouracil (5-FU) in the treatment of colorectal cancer is often affected by drug resistance or toxic side effects. Dihydropyrimidine dehydrogenase (DPD) is the key enzyme in the metabolism of 5-FU, and the expression or degradation rate of 5-FU may be a factor affecting the efficacy of 5-FU. Autophagy is an important pathway of intracellular protein degradation. This study aimed to detect the expression of microtubule-associated protein light chain 3 (LC3), P62 and DPD in colorectal cancer, and to explore their correlation and clinical significance, so as to provide a new way to reverse 5-FU resistance. Methods: Immunohistochemical envision method was used to detect the expressions of LC3, p62 and DPD in 157 colorectal cancer paraffin tissues archived by Department of Pathology, Binzhou Medical University Hospital from 2013 to 2014. Western blot and real-time fluorescence quantitative polymerase chain reaction (RTFQ-PCR) were used to detect the expressions of LC3, p62 and DPD in 44 colorectal cancer fresh tissues received by Department of Pathology, Binzhou Medical University Hospital in 2020. The correlation and clinical significance were analyzed. Results: The expressions of LC3, P62 and DPD were significantly higher in colorectal carcinoma than in normal tissues (P<0.05). The expressions of P62 was positively correlated with the expressions of DPD, and the expressions of LC3 was negatively correlated with the expressions of P62 and DPD (P<0.05). The expression of DPD was significantly higher in P62-/LC3- group than in the other three groups, while the expression of DPD was significantly lower in P62-/LC3+ group than in the other three groups (P<0.05). The protein expression of DPD in P62+/LC3- and P62+/LC3+ group were different, but the difference was not statistically significant (P>0.05). The expression of P62 was positively correlated with T stage and lymph node metastasis. The expression of LC3 was positively correlated with tumor size and T stage. The protein expression of DPD was closely related to histological type (P<0.05). LC3, P62, DPD and lymph node metastasis were related to the prognosis of colorectal cancer patients. All of them were independent risk factors for the prognosis of colorectal cancer. Conclusion: LC3 and p62 can affect the expression of DPD. Autophagy-lysosome pathway may be an important pathway of DPD degradation, which may affect the resistance of colorectal cancer to 5-FU through the degradation rate of DPD.
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