3,3'-diindolylmethane downregulates cyclin D1 through triggering endoplasmic reticulum stress in colorectal cancer cells

Lipid droplet deposition in the regenerating liver: A promoter, inhibitor, or bystander?

Liver regeneration (LR) is a complex process involving intricate networks of cellular connections, cytokines, and growth factors. During the early stages of LR, hepatocytes accumulate lipids, primarily triacylglycerol, and cholesterol esters, in the lipid droplets. Although it is widely accepted that this phenomenon contributes to LR, the impact of lipid droplet deposition on LR remains a matter of debate. Some studies have suggested that lipid droplet deposition has no effect or may even be detrimental to LR. This review article focuses on transient regeneration-associated steatosis and its relationship with the liver regenerative response.

3,3'-Diindolylmethane improves antitumor immune responses of PD-1 blockade via inhibiting myeloid-derived suppressor cells

Background

Immune checkpoint inhibitors that target programmed cell death protein 1 (PD-1) have obtained encouraging results, but a fraction of tumor patients failed to respond to anti-PD-1 treatment due to the existence of multiple immune suppressive elements such as myeloid-derived suppressor cells (MDSCs). Traditional Chinese medicine or natural products from medicinal plants could enhance immunity and may be helpful for cancer immunotherapy. As a digestive metabolite from cruciferous plants, 3,3′-diindolylmethane (DIM) has been widely used in chemotherapy, but its influence on cancer immunotherapy remains unclear. Here we investigate the function of DIM on MDSCs and examine the therapeutic effects of DIM in conjunction with PD-1 antibody against mouse tumors.

Methods

Flow cytometry analysis, Western blot analysis and qRT-PCR assay were used to examine the inhibitory effects and mechanisms of DIM on MDSCs in vitro and in vivo. The therapeutic effects of DIM on cancer immunotherapy by PD-1 antibody were evaluated in mouse models of breast cancer and melanoma tumor.

Results

DIM exerted the inhibitory effect on MDSCs via downregulating miR-21 level and subsequently activating PTEN/PIAS3-STAT3 pathways. Adoptive transfer of MDSCs impaired the therapeutic effects of DIM, indicating that the antitumor activity of DIM might be due to the suppression of MDSCs. Furthermore, in mouse models of breast cancer and melanoma tumor, the addition of DIM can enhance the therapeutic effect of PD-1 antibody through promoting T cells responses, and thereby inhibiting tumor growth.

Conclusions

Overall, the strategy based on the combination treatment of anti-PD-1 antibody and DIM may provide a new approach for cancer immunotherapy. Cruciferae plants-rich diet which contains high amount of DIM precursor may be beneficial for cancer patients that undergo the anti-PD-1 treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-022-00638-z.

Anti-proliferative effects of cell wall, cytoplasmic extract of Lactococcus lactis and nisin through down-regulation of cyclin D1 on SW480 colorectal cancer cell line

Background and Objectives:

Colorectal cancer is one of the most types of cancer. Researchers have shown that lactic acid bacteria have antitumor activity. The cell wall of Lactococcus lactis, as the bacterial cytoplasmic extract and nisin can affect the proliferation of cancer cells. Since cyclin D1 plays an important role in the progression of the cell cycle, its regulation can also be a therapeutic approach. We investigated the antiproliferative effect of cell wall, cytoplasmic extract and nisin on SW480 cancer cell line and the expression level of cyclin D1 gene in treated cancer cells.

Materials and Methods:

SW480 cell lines were treated with different concentrations of bacterial cell wall, cytoplasmic extract and nisin. MTT test was also performed. The expression level of cyclin D1 gene was determined using Real time PCR. Data were analyzed using Graph Pad Prism software.

Results:

The growth rate of cancer cells treated with nisin has significantly decreased compared to the cancer cells treated by other two substances (p< 0.05). Survival rates of the cancer cells treated by nisin at a concentration of 2000 μg, cytoplasmic extract, and cell wall were 34%, 47% and 49%, respectively. Real-time PCR results showed that cyclin D1 mRNA expression has significantly decreased in nisin treated sw480 cells (P<0.05).

Conclusion:

The results of this study show that nisin, bacterial cytoplasmic extract, and bacterial cell wall have antiproliferative effects, which are associated with the decreased expression of cyclin D1 in SW480 cell line.

PTEN/Akt Signaling-Mediated Activation of the Mitochondrial Pathway Contributes to the 3,3'-Diindolylmethane-Mediated Antitumor Effect in Malignant Melanoma Cells

3,3'-diindolylmethane (DIM) has an anticancer activity, but the role DIM plays on malignant melanoma cells and its specific mechanism is unclear. We studied the biological effects of DIM on malignant melanoma cells and the related mechanism and the results showed that DIM significantly suppressed cell proliferation and induced apoptosis in malignant melanoma cells. In addition, the expression levels of phosphatase and tensin homolog deleted on chromosome ten (PTEN), Bax, Bid, cleaved caspase-3, and cleaved caspase-9 were increased after DIM treatment. In A2058 PTEN^mut cells, DIM-mediated inhibition of proliferation and DIM-induced apoptosis were attenuated. Additionally, the overexpression and knockdown of PTEN could regulate such effects of DIM in malignant melanoma cells. Furthermore, DIM exerted growth-inhibiting and apoptosis-inducing effects in vivo. This study demonstrated that DIM has antitumor effect in human malignant melanoma cells through the mitochondrial apoptotic pathway activated by PTEN/Akt signaling.

Anti-proliferative activity of A. Oxyphylla and its bioactive constituent nootkatone in colorectal cancer cells

Background

A. oxyphylla extract is known to possess a wide range of pharmacological activites. However, the molecular mechanism of A. oxyphylla and its bioactive compound nootkatone in colorectal cancer is unknown.

Methods

Our study aims to examine the role of A. oxyphylla and its bioactive compound nootkatone, in tumor suppression using several in vitro assays.

Results

Both A. oxyphylla extract and nootkatone exhibited antiproliferative activity in colorectal cancer cells. A. oxyphylla displayed antioxidant activity in colorectal cancer cells, likely mediated via induction of HO-1. Furthermore, expression of pro-apoptotic protein NAG-1 and cell proliferative protein cyclin D1 were increased and decreased respectively in the presence of A. oxyphylla. When examined for anticancer activity, nootkatone treatment resulted in the reduction of colony and spheroid formation. Correspondingly, nootkatone also led to increased NAG-1 expression and decreased cyclin D1 expression. The mechanism by which nootkatone suppresses cyclin D1 involves protein level regulation, whereas nootkatone increases NAG-1 expression at the transcriptional level. In addition to having PPARγ binding activity, nootkatone also increases EGR-1 expression which ultimately results in enhanced NAG-1 promoter activity.

Conclusion

In summary, our findings suggest that nootkatone is an anti-tumorigenic compound harboring antiproliferative and pro-apoptotic activity.

Modulation of dysregulated cancer metabolism by plant secondary metabolites: A mechanistic review

Several signaling pathways and basic metabolites are responsible for the control of metabolism in both normal and cancer cells. As emerging hallmarks of cancer metabolism, the abnormal activities of these pathways are of the most noticeable events in cancer. This altered metabolism expedites the survival and proliferation of cancer cells, which have attracted a substantial amount of interest in cancer metabolism. Nowadays, targeting metabolism and cross-linked signaling pathways in cancer has been a hot topic to investigate novel drugs against cancer. Despite the efficiency of conventional drugs in cancer therapy, their associated toxicity, resistance, and high-cost cause limitations in their application. Besides, considering the numerous signaling pathways cross-linked with cancer metabolism, discovery, and development of multi-targeted and safe natural compounds has been a high priority. Natural secondary metabolites have exhibited promising anticancer effects by targeting dysregulated signaling pathways linked to cancer metabolism. The present review reveals the metabolism and cross-linked dysregulated signaling pathways in cancer. The promising therapeutic targets in cancer, as well as the critical role of natural secondary metabolites for significant anticancer enhancements, have also been highlighted to find novel/potential therapeutic agents for cancer treatment.

MicroRNA-96-5p represses breast cancer proliferation and invasion through Wnt/β-catenin signaling via targeting CTNND1

Low miR-96-5p expression is characteristic of many cancers but its role in breast cancer (BCa) remains poorly defined. Here, the role of miR-96-5p in BC development was assessed. We demonstrate that exogenously expressing miR-96-5p inhibits the proliferative, migratory and invasive capacity of BCa cells. Mechanistically, miR-96-5p in BCa cells was found to target and downregulate catenin delta 1 (CTNND1) leading to decreased β-catenin expression, a loss of WNT11 signaling, reduced cyclin D1 levels and lower MMP7 expression. Exogenously expressing CTNND1 alleviated these effects. In summary, we are the first to reveal that miR-96-5p inhibits the proliferative, invasive and migratory phenotypes of BCa cells the targeting of CTNND1 and subsequent Wnt/β-catenin signaling. These data highlight miR-96-5p as a novel target for BC treatment.

Autophagy inhibition improves the chemotherapeutic efficacy of cruciferous vegetable-derived diindolymethane in a murine prostate cancer xenograft model

Prostate cancer is the second leading cause of cancer-related deaths in men in North America and there is an urgent need for development of more effective therapeutic treatments against this disease. We have recently shown that diindolylmethane (DIM) and several of its halogenated derivatives (ring-DIMs) induce death and protective autophagy in human prostate cancer cells. However, the in vivo efficacy of ring-DIMs and the use of autophagy inhibitors as adjuvant therapy have not yet been studied in vivo. The objective of this study was to determine these effects on tumor growth in nude CD-1 mice bearing bioluminescent androgen-independent PC-3 human prostate cancer cells. We found that chloroquine (CQ) significantly sensitized PC-3 cells to death in the presence of sub-toxic concentrations of DIM or 4,4'-Br2DIM in vitro. Moreover, a combination of DIM (10 mg/kg) and CQ (60 mg/kg), 3× per week, significantly decreased PC-3 tumor growth in vivo after 3 and 4 weeks of treatment. Furthermore, 4,4'-Br2DIM at 10 mg/kg (3× per week) significantly inhibited tumour growth after 4 weeks of treatment. Tissues microarray analysis showed that DIM alone or combined with CQ induced apoptosis marker TUNEL; the combination also significantly inhibited the cell proliferation marker Ki67. In conclusion, we have confirmed that DIM and 4,4'-Br2DIM are effective agents against prostate cancer in vivo and shown that inhibition of autophagy with CQ enhances the anticancer efficacy of DIM. Our results suggest that including selective autophagy inhibitors as adjuvants may improve the efficacy of existing and novel drug therapies against prostate cancer.