Non-Lethal Concentrations of CdCl2 Cause Marked Alternations in Cellular Stress Responses within Exposed Sertoli Cell Line

Cadmium toxicity and autophagy: a review

Cadmium (Cd) is an important environmental pollutant that poses a threat to human health and represents a critical component of air pollutants, food sources, and cigarette smoke. Cd is a known carcinogen and has toxic effects on the environment and various organs in humans. Heavy metals within an organism are difficult to biodegrade, and those that enter the respiratory tract are difficult to remove. Autophagy is a key mechanism for counteracting extracellular (microorganisms and foreign bodies) or intracellular (damaged organelles and proteins that cannot be degraded by the proteasome) stress and represents a self-protective mechanism for eukaryotes against heavy metal toxicity. Autophagy maintains cellular homeostasis by isolating and gathering information about foreign chemicals associated with other molecular events. However, autophagy may trigger cell death under certain pathological conditions, including cancer. Autophagy dysfunction is one of the main mechanisms underlying Cd-induced cytotoxicity. In this review, the toxic effects of Cd-induced autophagy on different human organ systems were evaluated, with a focus on hepatotoxicity, nephrotoxicity, respiratory toxicity, and neurotoxicity. This review also highlighted the classical molecular pathways of Cd-induced autophagy, including the ROS-dependent signaling pathways, endoplasmic reticulum (ER) stress pathway, Mammalian target of rapamycin (mTOR) pathway, Beclin-1 and Bcl-2 family, and recently identified molecules associated with Cd. Moreover, research directions for Cd toxicity regarding autophagic function were proposed. This review presents the latest theories to comprehensively reveal autophagy behavior in response to Cd toxicity and proposes novel potential autophagy-targeted prevention and treatment strategies for Cd toxicity and Cd-associated diseases in humans.

Azoramide ameliorates cadmium-induced cytotoxicity by inhibiting endoplasmic reticulum stress and suppressing oxidative stress

Background

Cadmium (Cd) is hazardous to human health because of its cytotoxicity and long biological half-life. Azoramide is a small molecular agent that targets the endoplasmic reticulum (ER) and moderates the unfolded protein response. However, its role in Cd-induced cytotoxicity remains unclear. This study was performed to investigate the protective effect of azoramide against Cd-induced cytotoxicity and elucidate its underlying mechanisms.

Methods

Inductively coupled plasma‒mass spectrometry was used to measure Cd concentrations in each tissue of ICR male mice. The human proximal tubule epithelial cell line HK-2 and the human retinal pigment epithelial cell line ARPE-19 were used in the in vitro study. Cell apoptosis was determined by DAPI staining, JC-1 staining, and annexin V/propidium iodide double staining. Intracellular oxidative stress was detected by MitoSOX red staining, western blot, and quantitative real-time PCR. Moreover, ER stress signaling, MAPK cascades, and autophagy signaling were analyzed by western blot.

Results

The present data showed that Cd accumulated in various organs of ICR mice, and the concentrations of Cd in the studied organs, from high to low, were as follows: liver > kidney > testis > lung > spleen > eye. Our study demonstrated that azoramide inhibited ER stress by promoting BiP expression and suppressing the PERK-eIF2α-CHOP pathway. Additionally, we also found that azoramide significantly decreased ER stress-associated radical oxidative species production, attenuated p38 MAPK and JNK signaling, and inhibited autophagy, thus suppressing apoptosis in HK-2 and ARPE-19 cells.

Conclusion

Our study investigated the effect of azoramide on Cd-induced cytotoxicity and revealed that azoramide may be a therapeutic drug for Cd poisoning.

Anti-MUC1 nanobody can synergize the Tamoxifen and Herceptin effects on breast cancer cells by inducing ER, PR and HER2 overexpression

INTRODUCTION

One of the most pressing concerns associated with breast cancer-targeted therapies is resistance to Tamoxifen and Herceptin. Such drug resistance is usually characterized by reduced expression of certain cell surface receptors. Some biological regimens can induce perceptible overexpression of these receptors in favor of drug responsiveness.

MATERIAL AND METHODS

In this research, drug-responsive MCF-7 and SKBR-3, along with drug-resistant MCF-7R (Tamoxifen resistant) and JIMT-1 (Herceptin resistant) breast cancer cell lines in 2D and 3D cultures were exposed to anti-MUC1 nanobody and then assessed for their ER, PR, and HER2 gene and protein expression using qRT-PCR and immunofluorescent staining analyses. Cell viability and the synergistic relationships of combination treatments were determined with MTT assay followed by CompuSyn software. Apoptotic cells were evaluated with Annexin V/propidium Iodide (PI) and acridine orange/ethidium bromide (AO/EB) staining.

RESULTS

Anti-MUC1 exposure elevated the expression levels of ER (42 folds), PR (18.5 folds), and HER2 (4.7 folds). As a result of co-treatment, the IC50 levels for Tamoxifen and Herceptin were reduced by up to 10 and 3 folds, respectively. MCF-7R cells responded positively to Tamoxifen, as evidenced by a 5-fold reduction in the IC50 and enhanced apoptosis.

CONCLUSION

The ER, PR, and HER2 overexpression after MUC1 blocking could signal drug hypersensitization and facilitate drug resistance management.