Hedgehog, Notch and Wnt developmental pathways as targets for anti-cancer drugs

Dibenzazepine Attenuates Against Cisplatin-Induced Nephrotoxicity in Rats: Involvement of NOTCH Pathway

Cisplatin is one of the standard anti-cancer agents that are used to treat variety of solid tumors. Nevertheless, due to the accumulation of cisplatin in the renal epithelial cells, nephrotoxicity was found to be the main side effect that limits its clinical use. The current study was conducted to assess the potential nephroprotective effect of dibenzazepine, a Notch inhibitor, against cisplatin-induced nephrotoxicity in rats as well as the possible mechanisms underlying this nephroprotection. The rats were pre-treated with 2 mg/kg dibenzazepine for 7 days before giving a single nephrotoxic dose of cisplatin (7 mg/kg). Cisplatin induced acute nephrotoxicity, where blood urea nitrogen and serum creatinine levels were significantly increased. Besides, lipid peroxidation was markedly elevated and the levels of reduced glutathione and catalase were significantly reduced. Also, the tissue levels of the pro-inflammatory mediators; IL-1β, TNF-α, and NF-kB, were significantly increased in the cisplatin group. The pre-treatment with dibenzazepine significantly mitigated the nephrotoxic effects of cisplatin, the oxidative stress and inflammatory status as well as decreased caspase-3 expression, as compared to the cisplatin group. Furthermore, the up-regulation of Notch-1 and Hes-1 was found to be involved in cisplatin-induced nephrotoxicity and their expression was significantly reduced by dibenzazepine. The nephroprotective effect of dibenzazepine was further confirmed by the histopathological assessment. Moreover, dibenzazepine pre-treatment of hela and PC3 cells in vitro did not antagonize the cisplatin anti-cancer activity. In conclusion, these findings show that dibenzazepine provides protection against cisplatin-induced nephrotoxicity. Moreover, the up-regulation of the Notch pathway was shown to play a role in the pathogenesis of cisplatin-induced renal injury.

Novel Therapeutics Against Breast Cancer Stem Cells by Targeting Surface Markers and Signaling Pathways

Background:

Breast cancer remains to be one of the deadliest forms of cancers, owing to the drug resistance and tumor relapse caused by breast cancer stem cells (BCSCs) despite notable advancements in radio-chemotherapies.

Objective:

To find out novel therapeutics against breast cancer stem cells by aiming surface markers and signaling pathways.

Methods:

A systematic literature search was conducted through various electronic databases including, Pubmed, Scopus, Google scholar using the keywords "BCSCs, surface markers, signaling pathways and therapeutic options against breast cancer stem cell. Articles selected for the purpose of this review were reviewed and extensively analyzed.

Results:

Novel therapeutic strategies include targeting BCSCs surface markers and aberrantly activated signaling pathways or targeting their components, which play critical roles in self-renewal and defense, have been shown to be significantly effective against breast cancer. In this review, we represent a number of ways against BCSCs surface markers and hyper-activated signaling pathways to target this highly malicious entity of breast cancer more effectively in order to make a feasible and useful strategy for successful breast cancer treatment. In addition, we discuss some characteristics of BCSCs in disease progression and therapy resistance.

Conclusion:

BCSCs involved in cancer pathogenesis, therapy resistance and cancer recurrence. Thus, it is suggested that a multi-dimensional therapeutic approach by targeting surface markers and aberrantly activated signaling pathways of BCSCs alone or in combination with each other could really be worthwhile in the treatment of breast cancer.

Cigarette smoke stimulates the stemness of renal cancer stem cells via Sonic Hedgehog pathway

Cancer stem cells (CSCs) are essentially responsible for tumor initiation, growth, progression, metastasis and recurrence, and cigarette smoke (CS) is closely involved in the occurrence and development of kidney cancer. However, the effect of CS on renal CSCs has not been elucidated yet. In the present study, tumorsphere formation assay was used to enrich renal CSCs from 786-O and ACHN cells. We illustrated that CS effectively promoted renal CSCs stemness by enhancing tumorsphere formation, increasing the expression of renal CSCs markers (CD133, CD44, ALDHA1, Oct4, and Nanog) and elevating CD133+ cell population. Moreover, our results showed that CS triggered the activation of Sonic Hedgehog (SHH) pathway, while inhibition of SHH pathway dampened the promotive effects of CS on renal CSCs. Finally, higher levels of renal CSCs markers and SHH pathway-related proteins were observed in kidney cancer tissues from smokers than non-smoking cancer tissues. Taken together, these results demonstrated the important role of SHH pathway in regulating CS-induced renal CSCs stemness augment. Findings from this study could provide new insight into the molecular mechanisms of CS-elicited stemness of renal CSCs.

A reporter gene system for screening inhibitors of Wnt signaling pathway

Abnormal activation of canonical Wnt signaling has been associated with various types of cancer. Inhibitory reagents targeting the Wnt signaling have great potential to inhibit the growth of relevant tumors. Here we generated a cell-based screening strategy for identification of antagonists of the Wnt/β-catenin signaling pathway. Stable expression wnt3a was generated in HEK293 cell line, which harbors dual-luciferase reporters. The Wnt signaling in the stably transfected cell line was proved to be very sensitive to (−)-epigallocatechin-3-gallate (EGCG) and lithium chloride (LiCl) treatment, respectively. Natural compounds were screened and a couple of novel inhibitory modulators of the Wnt signaling pathway were obtained.

Connexin 43 reverses malignant phenotypes of glioma stem cells by modulating E-cadherin

Malfunctioned gap junctional intercellular communication (GJIC) has been thought associated with malignant transformation of normal cells. However, the role of GJIC-related proteins such as connexins in sustaining the malignant behavior of cancer stem cells remains unclear. In this study, we obtained tumorspheres formed by glioma stem cells (GSCs) and adherent GSCs and then examined their GJIC. All GSCs showed reduced GJIC, and differentiated glioma cells had more gap junction-like structures than GSCs. GSCs expressed very low level of connexins, Cx43 in particular, which are key components of gap junction. We observed hypermethylation in the promoter of gap junction protein α1, which encodes Cx43 in GSCs. Reconstitution of Cx43 in GSCs inhibited their capacity of self-renewal, invasiveness, and tumorigenicity via influencing E-cadherin and its coding protein, which leads to changes in the expression of Wnt/β-catenin targeting genes. Our results suggest that GSCs require the low expression of Cx43 for maintaining their malignant phenotype, and upregulation of Cx43 might be a potential strategy for treatment of malignant glioma.