PLAC8 inhibits oral squamous cell carcinogenesis and epithelial-mesenchymal transition via the Wnt/β-catenin and PI3K/Akt/GSK3β signaling pathways

PLAC8 contributes to the malignant behaviors of cervical cancer cells by activating the SOX4-mediated AKT pathway

Cervical cancer (CC) is the primary cancer-related cause of morbidity and mortality in women. Previous studies have shown that placenta-specific 8 (PLAC8) has different functions in multiple malignancies. This study aimed to explore the function and regulatory mechanism of PLAC8 in CC. Bioinformatics and immunohistochemical analyses demonstrated that PLAC8 was significantly upregulated in CC tissues compared with normal tissues. Gain/loss-of-function experiments showed that siRNA-mediated knockdown of PLAC8 suppressed cell migration and invasion, while PLAC8 overexpression promoted cell motility. Moreover, PLAC8 was revealed to affect the epithelial-mesenchymal transition (EMT) process by upregulating epithelial (E)-cadherin and decreasing the expression of mesenchymal markers of EMT, including vimentin, zinc finger E-box binding homeobox 1 (ZEB1), neural (N)-cadherin, matrix metalloproteinase-9 (MMP-9), and MMP-2 in PLAC8-silenced cells. PLAC8 activated the AKT pathway, as proven by the downregulation of p-AKT_Ser473 and p-AKT_Thr308 expression after PLAC8 knockdown. Furthermore, PLAC8 overexpression upregulated the expression of sex-determining region Y-related high-mobility group box transcription factor 4 (SOX4), which is reported to mediate the activation of the AKT pathway, and SOX4 deficiency reversed the cellular functions caused by PLAC8 overexpression. Overall, the present study indicates that PLAC8 may facilitate CC development by activating the SOX4-mediated AKT pathway, suggesting that PLAC8 may serve as a potential biomarker for CC treatment.

Insight of Autophagy in Spontaneous Miscarriage

In some cases of spontaneous miscarriage (SM), the exact etiology cannot be determined. Autophagy, which is responsible for cellular survival under stress conditions, has also been implicated in many diseases. Recently, it is also surmised to be correlated with SM. However, the detailed mechanism remains elusive. In fact, there are several essential steps during pregnancy establishment and maintenance: trophoblasts invasion, placentation, decidualization, enrichment and infiltration of decidua immune cells (e.g., natural killer, macrophage and T cells). Accordingly, upstream molecules and downstream effects of autophagy are discussed in these processes, respectively. Of note, autophagy regulates the crosstalk between these cells at the maternal-fetal interface as well. Aberrant autophagy is found in villi, decidual stromal cells, peripheral blood mononuclear cells in SM patients, although the findings are inconsistent among different studies. Furthermore, potential treatments targeting autophagy are included, during which rapamycin and vitamin D are hot-spots in recent literatures. To conclude, a moderately activated autophagy is deeply involved in pregnancy, suggesting that autophagy should be a regulator and promising target for treating SM.

Multifaced roles of PLAC8 in cancer

The role of PLAC8 in tumorigenesis has been gradually elucidated with the development of research. Although there are common molecular mechanisms that enforce cell growth, the impact of PLAC8 is varied and can, in some instances, have opposite effects on tumorigenesis. To systematically understand the role of PLAC8 in tumors, the molecular functions of PLAC8 in cancer will be discussed by focusing on how PLAC8 impacts tumorigenesis when it arises within tumor cells and how these roles can change in different stages of cancer progression with the ultimate goal of suppressing PLAC8-relevant cancer behavior and related pathologies. In addition, we highlight the diversity of PLAC8 in different tumors and its functional output beyond cancer cell growth. The comprehension of PLAC8's molecular function might provide new target and lead to the development of novel anticancer therapies.