SOX2 as a prognostic marker and a potential molecular target in cervical cancer: A meta-analysis

Cancer stem cell biomarkers SOX2 and Oct4 in cervical cancer patients undergoing chemoradiotherapy

BACKGROUND

Cancer stem cell biomarkers SRY (sex-determining region Y)-box 2 (SOX2) and octamer-binding transcription factor 4 (Oct4) account for radioresistance in cervical squamous cell cancers (CSCCs). Their clinical implications are limited and contradictory.

METHODS

In this prospective cohort study, we recruited patients with FIGO IB2-IVA CSCC treated with primary chemoradiotherapy on regular follow-up. Tissue biopsy specimens were evaluated for SOX2 and Oct4 expression by immunohistochemistry, quantified by a product of proportion and intensity scores.

RESULTS

A total of 59 patients were included. Most had a moderately differentiated (81%), keratinizing (59%) CSCC, and ≥FIGO stage IIB disease (95%). SOX2 expression (high:low 21:38 patients) and Oct4 expression (high:low 4:55 patients) had a significant interrelation (p = 0.005, odds ratio (95% CI) - 1.23 (1.004-1.520)). At a median follow-up of 36 months, the 3-year overall survival (OS) was 60% and 53% for low and high SOX2 expression (p = 0.856), and 54% and 100% for low and high Oct4 expression (p = 0.114). The 3-year disease-frese survival (DFS) was 65% and 50% in the low and high SOX2 expression (p = 0.259), and 59% and 75% for low and high Oct4 expression (p = 0.598). SOX2 expression was the only variable significantly associated with a lower OS and DFS on regression analysis.

CONCLUSION

Our study demonstrated a trend toward improved OS and DFS with low SOX2 and high Oct4 expression in CSCC patients undergoing chemoradiotherapy.

The relationship of immunohistochemical SOX-2 staining with histopathological diagnosis in patients with abnormal colposcopic findings

This study aimed to analyze immunohistochemical staining and pathological data in cervical intraepithelial neoplasia (CIN) and squamous cell cervical carcinoma (SCC) with abnormal colposcopic findings. A histopathological evaluation of 45 low-grade squamous lesions (LSILs), 177 high-grade squamous lesions (HSILs) and 16 SCC biopsy materials from existing slides was obtained from blocks obtained from the archive. In addition, SOX-2 immunohistochemical staining was evaluated. The mean age of the HSIL group was 43.20 ± 8.97 years, younger than the mean age of the LSIL group of 51.62 ± 9.64 years (p = 0.000). There was no difference between the groups regarding the method of biopsy (p > 0.05). Endocervical gland involvement was not observed in the LSIL group, but was observed in 66 (37.3%) biopsy materials in the HSIL group (p = 0.000). There was a difference between the groups in terms of the level of CIN at the surgical margin (p = 0.000). Ki-67, SOX-2 staining percentage and p16INK4a positivity were higher in the HSIL group than in the LSIL group (respectively, 67.57 ± 19.10 vs. 14.62 ± 7.11, p = 0.000; 27.72 ± 31.56 vs. 10.09 ± 15.38, p = 0.003; 66 (82.5%) vs. 8 (44.4%), p = 0.001). While there was no difference in SOX-2 intensity between the HSIL and LSIL groups (p > 0.05), it was statistically significantly higher in the SCC group (p = 0.000), as was the percentage of SOX-2 (p = 0.000). We have shown that p16INK4a and SOX-2 staining is useful, in addition to Ki-67 immunostaining, which is widely used for SCC, which is one of the preventable cancer types. In addition, SOX-2 may provide a glimmer of hope in the development of SCC treatment modalities, especially since it is aggressively elevated in SCC rather than CIN lesions.

SOX2-associated signaling pathways regulate biological phenotypes of cancers

SOX2 is a transcription factor involved in multiple stages of embryonic development. In related reports, SOX2 was found to be abnormally expressed in tumor tissues and correlated with clinical features such as TNM staging, tumor grade, and prognosis in patients with various cancer types. In most cancer types, SOX2 is a tumor-promoting factor that regulates tumor progression and metastasis primarily by maintaining the stemness of cancer cells. In addition, SOX2 also regulates the proliferation, apoptosis, invasion, migration, ferroptosis and drug resistance of cancer cells. However, SOX2 acts as a tumor suppressor in some cases in certain cancer types, such as gastric and lung cancer. These key regulatory functions of SOX2 involve complex regulatory networks, including protein-protein and protein-nucleic acid interactions through signaling pathways and noncoding RNA interactions, modulating SOX2 expression may be a potential therapeutic strategy for clinical cancer patients. Therefore, we sorted out the phenotypes related to SOX2 in cancer, hoping to provide a basis for further clinical translation.

Evaluation of the Effectiveness of Various Autophagy Inhibitors in A549 Cancer Stem Cells

Numerous studies have already established that autophagy plays a central role in the survival of all cells, including malignant ones. Autophagy is a central cog in the general mechanism that provides the intracellular proteostasis determining cellular physiological and phenotypic characteristics. The accumulated data show that autophagy largely contributes to cancer cell stemness. Thus, autophagy modulation is considered one of the promising pharmacological targets in therapy aimed at cancer stem cell elimination. However, autophagy is a multi-stage intracellular process that involves numerous protein participants. In addition, the process can be activated simultaneously by various signaling modules. Therefore, it is no small feat to select an effective pharmacological drug against autophagy. What's more, the search for potential chemotherapeutic agents that could eliminate cancer stem cells through pharmacological inhibition of autophagy is still under way. In the present work, we selected a panel of autophagy inhibitors (Autophinib, SBI-0206965, Siramesine, MRT68921, and IITZ-01), some of whom have been recently identified as effective autophagy inhibitors in cancer cells. Using A549 cancer cells, which express the core stem factors Oct4 and Sox2, we evaluated the effect of these drugs on the survival and preservation of the original properties of cancer stem cells. Among the agents selected, only Autophinib demonstrated a significant toxic effect on cancer stem cells. The obtained results demonstrate that autophagy inhibition by Autophinib downregulates the expression of the Sox2 protein in A549 cells, and that this downregulation correlates with a pronounced induction of apoptosis. Moreover, Autophinib-treated A549 cells are unable to form spheroids, which indicates a reduction in stemness. Thus, among the drugs studied, only Autophinib can be considered a potential agent against cancer stem cells.