Inhibition of pRB Pathway Differentially Modulates Apoptosis in Esophageal Cancer Cells

β-Carotene Attenuates Apoptosis and Autophagy via PI3K/AKT/mTOR Signaling Pathway in Necrotizing Enterocolitis Model Cells IEC-6

Background

Necrotizing enterocolitis (NEC) is a devastating disease affecting the gastrointestinal tract in the newborn period. In recent years, the role of apoptosis and autophagy in intestinal mucosal barrier dysfunction has come into prominence in research regarding the pathogenesis of NEC. β-Carotene is a well-known vitamin A precursor, and its content in breast milk is relatively high, especially in the colostrum. In the present study, we investigated the protective effect of β-carotene on necrotizing enterocolitis model cells IEC-6 induced by lipopolysaccharide (LPS).

Methods

CCK-8 assay was performed to evaluate cell viability. The Annexin V-FITC/PI method was used to detect apoptosis. Western blotting was utilized to measure the expression levels of proteins. Immunofluorescence analysis was used to assess the autophagy of IEC-6 cells.

Results

Our findings indicated that β-carotene inhibited the apoptosis of IEC-6 cells by downregulating cleaved caspase-3 levels and Bax levels and upregulating Bcl-2 levels, reducing cell autophagy via downregulating LC3II/I ratio and upregulating p62 levels. In addition, the expression of p-PI3K, p-AKT, and p-mTOR was upregulated after β-carotene treatment. Interestingly, these changes induced by β-carotene were partially reversed by rapamycin and voxtalisib.

Conclusion

In conclusion, our findings indicated that β-carotene can attenuate apoptosis and autophagy of IEC-6 cells induced by LPS via activating the PI3K/AKT/mTOR signaling pathway. Therefore, β-carotene may be a promising drug used in the clinical treatment of NEC.

Molecular mechanisms of quinalizarin induces apoptosis and G0/G1 cell cycle of human esophageal cancer HCE-4 cells depends on MAPK, STAT3, and NF-κB signaling pathways

Quinalizarin (Quina) is one of the main components of many herbal medicines and has good anti-tumor activity. However, the exact mode of cytotoxic action and signaling pathways on Quina in human esophageal cancer has not yet been confirmed. In this study, we explored the anticancer effect of Quina against human esophageal cancer HCE-4 cells and the underlying mechanisms. The results of the Cell Counting Kit-8 (CCK-8) assay showed that Quina inhibited the viability of human esophageal cancer HCE-4 cells in a dose-dependent and time-dependent manner. It also inhibited HCE-4 cells proliferation and induced apoptosis by increasing the levels of Bad, caspase-3, and PARP, decreasing the level of Bcl-2. The results of the cell cycle analysis suggested that Quina arrested HCE-4 cells in the G0/G1 cycle by downregulating cyclin-dependent (CDK) 2/4, cyclin D1/E and upregulating the levels of p21 and p27. We also found that Quina activated mitogen-activated protein kinase (MAPK) and inhibited the signal transducer and activator of transcription-3 (STAT3) and nuclear factor kappa B (NF-κB) signaling pathways. Furthermore, Quina significantly increased intracellular reactive oxygen species (ROS) level. The pretreatment of N-acetyl-L-cysteine (NAC) blocked the apoptosis induced by Quina and inhibited the activities of MAPK, STAT3, and NF-κB signaling pathways. These results indicate that Quina induces the apoptosis in HCE-4 cells, which is via accumulating ROS generation and regulating MAPK, STAT3, and NF-κB. In conclusion, this study demonstrated that Quina have good therapeutic effects on human esophageal cancer cells.

Tumor Suppressors Having Oncogenic Functions: The Double Agents

Cancer progression involves multiple genetic and epigenetic events, which involve gain-of-functions of oncogenes and loss-of-functions of tumor suppressor genes. Classical tumor suppressor genes are recessive in nature, anti-proliferative, and frequently found inactivated or mutated in cancers. However, extensive research over the last few years have elucidated that certain tumor suppressor genes do not conform to these standard definitions and might act as “double agents”, playing contrasting roles in vivo in cells, where either due to haploinsufficiency, epigenetic hypermethylation, or due to involvement with multiple genetic and oncogenic events, they play an enhanced proliferative role and facilitate the pathogenesis of cancer. This review discusses and highlights some of these exceptions; the genetic events, cellular contexts, and mechanisms by which four important tumor suppressors—pRb, PTEN, FOXO, and PML display their oncogenic potentials and pro-survival traits in cancer.

Highlights in Resistance Mechanism Pathways for Combination Therapy

Combination chemotherapy has been a mainstay in cancer treatment for the last 60 years. Although the mechanisms of action and signaling pathways affected by most treatments with single antineoplastic agents might be relatively well understood, most combinations remain poorly understood. This review presents the most common alterations of signaling pathways in response to cytotoxic and targeted anticancer drug treatments, with a discussion of how the knowledge of signaling pathways might support and orient the development of innovative strategies for anticancer combination therapy. The ultimate goal is to highlight possible strategies of chemotherapy combinations based on the signaling pathways associated with the resistance mechanisms against anticancer drugs to maximize the selective induction of cancer cell death. We consider this review an extensive compilation of updated known information on chemotherapy resistance mechanisms to promote new combination therapies to be to discussed and tested.

UGT2B17 and miR-224 contribute to hormone dependency trends in adenocarcinoma and squamous cell carcinoma of esophagus

Esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EA) are the two main subtypes of esophageal cancer. Genetics underpinnings of EA are substantially less understood than that of ESCC. A large-scale relation data analysis was conducted to explore the genes implicated with either EA or ESCC, or both. Each gene linked to ESCC but not EA was further explored in mega-analysis of six independently collected EA RNA expression datasets. A multiple linear regression (MLR) model was built to study the possible influence of sample size, population region, and study date on the gene expression data in EA. Finally, a functional pathway analysis was conducted to identify the possible linkage between EA and the genes identified as novel significant contributors. We have identified 276 genes associated with EA, 1088 with ESCC, with a significant (P<5.14e-143) overlap between these two gene groups (n=157). Mega-analysis showed that two ESCC-related genes, UGT2B17 and MIR224, were significantly associated with EA (P-value <1e-10), with multiple connecting pathways revealed by functional analysis. ESCC and EA share some common pathophysiological pathways. Further study of UGT2B17 and MIR224, which are differentially dysregulated in ESCC and EA tumors, is warranted. Enhanced expression of UGT2B17 and the lack of miR-224 signaling may contribute to the responsiveness of EA to the male sex steroids.