The detection of SAS1B in serum provides clues for early diagnosis of thyroid cancer

OBJECTIVE

The incidence of thyroid cancer is rising globally. Most patients progress slowly, but some patients develop lymph node and distant metastasis earlier, and their prognosis is poor. Therefore, early diagnosis and warning of malignancy are very meaningful for such patients. SAS1B gene is a newly discovered protein expressed on the surface of mature egg cells and has metalloendopeptidase activity. We aimed at exploring whether SAS1B is involved in the occurrence of thyroid cancer, and at providing evidence for early diagnosis and targeted therapy of thyroid cancer.

PATIENTS AND METHODS

In this study, a rabbit anti-human SAS1B polyclonal antibody was prepared by gene recombination technology. The indirect ELISA method was used to detect the SAS1B protein expression in the serum of 69 patients with thyroid cancer and 55 normal controls, and the relevant pathological factors were analyzed. Immunohistochemistry and PCR technology were used to investigate the expression levels of SAS1B protein and mRNA in 30 thyroid cancer tissues and 23 control thyroid tissues.

RESULTS

The titer of SAS1B recombinant antibody was 1:51200. The expression of SAS1B in the serum of patients with thyroid cancer was higher than that in the normal control group (p<0.01). The antibody had a good sensitivity in serum detection of cancer patients (p=0.008<0.01), the linear regression analysis result was that the expression of SAS1B gene was related to tumor envelope invasion and lymph node metastasis (p=0.003<0.01, p=0.003<0.01), and it was irrelevant to the patient's gender, age, tumor mass size, number of cancer foci, pathological stage, etc. (p>0.05). The results of immunohistochemistry showed that SAS1B protein was mainly located in the cytoplasm and membrane of thyroid cancer cells. The expression intensity in thyroid cancer tissues was higher than that in control tissues (p<0.05), but it was not expressed in normal thyroid tissues. Antibodies showed a good sensitivity that was used to detect thyroid cancer tissues (p=0.000<0.01). The results of ordinary PCR detection using thyroid cancer tissue and control thyroid tissue showed that the amplification products of the three domains (N-terminal, C-terminal and catalytic domain) of the SAS1B gene showed high expression in thyroid cancer tissue. q-PCR results showed that the expression of SAS1B gene in thyroid cancer and control thyroid tissue was higher than that in control group (p<0.05), and the genes of Aurora A and BARD1 related to centrosome replication and DNA replication forks protection during the proliferation were highly expressed in thyroid cancer tissue. The study results suggested that SAS1B was involved in the carcinogenesis of thyroid cancer. The Hum_mPLoc.2.0 software, PSORT Ⅱ software and UniProt software were used to predict that SAS1B protein had secretory protein properties.

CONCLUSIONS

The above data indicate that the SAS1B gene is closely related to the process of thyroid cancer and can serve as a good tumor marker that can be used for early diagnosis and early warning of thyroid malignancy.

Anti-breast cancer activity of resveratrol encapsulated in liposomes

Resveratrol (RES) is a naturally occurring and effective drug for tumor prevention and treatment. However, its low levels of aqueous solubility, stability, and poor bioavailability limit its application, especially when used as a free drug. In this study, RES was loaded into peptide and sucrose liposomes (PSL) to enhance the physico-chemical properties of RES and exploit RES delivery mediated by liposomes to effectively treat breast cancer. RES loaded PSL (the complex: PSL@RES) were stable, had a good RES encapsulation efficiency, and prolonged RES-release in vitro. PSL@RES was exceptionally efficient for inhibiting the growth of cancer cells, as the IC₅₀ of PSL@RES in MCF-7 cells was found to be only 20.89 μmol L^-1. The therapeutic efficacy of PSL@RES was evaluated in mice bearing breast cancer. The results showed that PSL@RES at a dosage of 5 mg kg^-1 was more effective than 10 mg kg^-1 free RES, and PSL@RES inhibited tumor growth completely at a dosage of 10 mg kg^-1. PSL@RES induced apoptosis in breast tumor by upregulation of p53 expression. This then downregulated Bcl-2 and upregulated Bax, thereby inducing Caspase-3 activation. More importantly, encapsulation of RES within peptide liposomes greatly reduced the toxicity of free RES to mice. Overall, the simple formulation of liposomal nanocarriers of RES developed in this study produces satisfactory outcomes to encourage further applications of liposomal carriers for the treatment of breast cancer.