Hedgehog Pathway Activation Might Mediate Pemetrexed Resistance in NSCLC Cells

Vismodegib Potentiates Marine Antimicrobial Peptide Tilapia Piscidin 4-Induced Cytotoxicity in Human Non-Small Cell Lung Cancer Cells

Non-small cell lung cancer (NSCLC) is a common cancer with several accepted treatments, such as chemotherapy, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors, and immune checkpoint inhibitors. Nevertheless, NSCLC cells often become insensitive to these treatments, and therapeutic resistance is a major reason NSCLC still has a high mortality rate. The induction of therapeutic resistance in NSCLC often involves hedgehog, and suppression of hedgehog can increase NSCLC cell sensitivity to several conventional therapies. In our previous work, we demonstrated that the marine antimicrobial peptide tilapia piscidin 4 (TP4) exhibits potent anti-NSCLC activity in both EGFR-WT and EGFR-mutant NSCLC cells. Here, we sought to further explore whether hedgehog might influence the sensitivity of NSCLC cells to TP4. Our results showed that hedgehog was activated by TP4 in both WT and EGFR-mutant NSCLC cells and that pharmacological inhibition of hedgehog by vismodegib, a Food and Drug Administration-approved hedgehog inhibitor, potentiated TP4-induced cytotoxicity. Mechanistically, vismodegib acted by enhancing TP4-mediated increases in mitochondrial membrane potential and intracellular reactive oxygen species (ROS). MitoTempo, a specific mitochondrial ROS scavenger, abolished vismodegib/TP4 cytotoxicity. The combination of vismodegib with TP4 also reduced the levels of the antioxidant proteins catalase and superoxide dismutase, and it diminished the levels of chemoresistance-related proteins, Bcl-2 and p21. Thus, we conclude that hedgehog regulates the cytotoxic sensitivity of NSCLC cells to TP4 by protecting against mitochondrial dysfunction and suppressing oxidative stress. These findings suggest that combined treatment of vismodegib and TP4 may be a promising therapeutic strategy for NSCLC.

Ginsenoside Rb1 for overcoming cisplatin-insensitivity of A549/DDP cells in vitro and vivo through the dual-inhibition on two efflux pumps of ABCB1 and PTCH1

BACKGROUND

The multi-drug resistance is an inherent weakness in the chemotherapeutics of non-small cell lung cancer occurring frequently all over the world. Clinically, ginseng and Chinese medicinal prescriptions including ginseng usually used as anti-tumor adjuncts due to its characteristic of qi-invigorating, which could improve the curative effect of chemotherapy drugs and reduce their toxic side effects. Triterpenoid saponins are the crucial active ingredients in Panax ginseng, and Ginsenoside Rb₁ is of the highest quantities. However, the research on the tumor drug-resistance reversal effect and mechanism of ginsenoside Rb₁ is still not clear.

PURPOSE

This study aimed to systematically estimate the reversal activity of Ginsenoside Rb₁ on cisplatin-insensitivity of A549/DDP cells and to reveal its prospective molecular mechanism.

METHODS

MTT assay were conducted to evaluate the reversal activity on cisplatin-insensitivity of A549/DDP cells of Ginsenoside Rb₁in vitro, and the behavior was also studied by establishing a subcutaneous transplanted tumor model of A549/DDP in BALB/c-nu mice. In addition, P-gp ATPase activity assay, cisplatin accumulation assay, Annexin V-FITC apoptosis assay, real-time qPCR analysis and western blotting analysis were used to clarify the potential mechanism.

RESULTS

Ginsenoside Rb₁ could effectively reverse the cisplatin-resistance of A549/DDP in vitro and vivo. And after the co-treatment of Ginsenoside Rb₁ plus cisplatin, the accumulation of cisplatin increased in A549/DDP cells, which was accompanied with the down-regulation of the mRNA and protein expression levels of ABCB1, SHH, PTCH1 and GLI2. Besides, the apoptosis-inducing ability of cisplatin improved by the relative regulation on the protein expression level of Bax and Bcl-2. Far more importantly, the changes of CYP3A4 mRNA and protein levels were not significant.

CONCLUSION

Ginsenoside Rb₁ could increase the concentration of intracellular cisplatin and improve the insensitivity for cisplatin on A549/DDP cells. Even better, there was perhaps no unpredictable CYP3A4-mediated pharmacokinetic interactions after the combination of Ginsenoside Rb₁ plus cisplatin. Ginsenoside Rb₁ was a probable reversal agent for the cisplatin-insensitivity of A549/DDP cells, with a bifunction of inhibiting the efflux of two drug pumps (P-gp and PTCH1) by targeting ABCB1 and Hedgehog (Hh) pathway. In general, this research laid the groundwork for the development of a new reversal agent for the cisplatin-insensitivity of NSCLC.

The Role of Notch, Hedgehog, and Wnt Signaling Pathways in the Resistance of Tumors to Anticancer Therapies

Resistance to therapy is the major hurdle in the current cancer management. Cancer cells often rewire their cellular process to alternate mechanisms to resist the deleterious effect mounted by different therapeutic approaches. The major signaling pathways involved in the developmental process, such as Notch, Hedgehog, and Wnt, play a vital role in development, tumorigenesis, and also in the resistance to the various anticancer therapies. Understanding how cancer utilizes these developmental pathways in acquiring the resistance to the multi-therapeutic approach cancer can give rise to a new insight of the anti-therapy resistance mechanisms, which can be explored for the development of a novel therapeutic approach. We present a brief overview of Notch, Hedgehog, and Wnt signaling pathways in cancer and its role in providing resistance to various cancer treatment modalities such as chemotherapy, radiotherapy, molecular targeted therapy, and immunotherapy. Understanding the importance of these molecular networks will provide a rational basis for novel and safer combined anticancer therapeutic approaches for the improvement of cancer treatment by overcoming drug resistance.

Mechanisms of resistance to chemotherapy in non-small cell lung cancer

Non-small cell lung cancer (NSCLC), which represents 80-85% of lung cancer cases, is one of the leading causes of human death worldwide. The majority of patients undergo an intensive and invasive treatment regimen, which may include radiotherapy, chemotherapy, targeted therapy, immunotherapy, or a combination of these, depending on disease stage and performance status. Despite advances in therapeutic regimens, the 5-year survival of NSCLC is approximately 20-30%, largely due to diagnosis at advanced stages. Conventional chemotherapy is still the standard treatment option for patients with NSCLC, especially those with advanced disease. However, the emergence of resistance to chemotherapeutic agents (chemoresistance) poses a significant obstacle to the management of patients with NSCLC. Therefore, to develop efficacious chemotherapeutic approaches for NSCLC, it is necessary to understand the mechanisms underlying chemoresistance. Several mechanisms are known to mediate chemoresistance. These include altered cellular targets for chemotherapy, decreased cellular drug concentrations, blockade of chemotherapy-induced cell cycle arrest and apoptosis, acquisition of epithelial-mesenchymal transition and cancer stem cell-like phenotypes, deregulated expression of microRNAs, epigenetic modulation, and the interaction with tumor microenvironments. In this review, we summarize the mechanisms underlying chemoresistance and tumor recurrence in NSCLC and discuss potential strategies to avoid or overcome chemoresistance.

Hsa_circ_0008537 facilitates liver carcinogenesis by upregulating MCL1 and Snail1 expression via miR‑153‑3p

The biological functions of circular RNAs in liver tumorigenesis have been well demonstrated by a number of studies. Nevertheless, to the best of our knowledge, the role and mechanism of action of hsa_circ_0008537 (circ_0008537) in liver cancer pathogenesis remain undetermined. In the present study, circ_0008537 expression was associated with the GLI3 gene and was markedly increased in liver cancer tissue specimens and cells. High expression levels of circ_0008537 exhibited a poor prognosis. In addition, circ_0008537 overexpression resulted in an increased proliferation, migration and invasion of liver cancer cells, whereas circ_0008537 knockdown exhibited opposite effects. circ_0008537 acted as a sponge of microRNA-153-3p (miR-153-3p), and a negative correlation was observed between circ_0008537 and miR-153-3p expression in liver cancer. Transfection with miR-153-3p further abolished the effects of circ_0008537 on the malignant behavior of liver cancer cells. Furthermore, circ_0008537 indirectly affected the expression levels of pro-survival protein myeloid cell leukemia 1 (MCL1) and snail family zinc finger 1 (Snail1) via miR-153-3p in liver cancer cells. In conclusion, the data indicated that circ_0008537 facilitated liver carcinogenesis by indirectly regulating miR-153-3p and leading to the release of MCL1 and Snail1.

High-Risk Recurrence Basal Cell Carcinoma: Focus on Hedgehog Pathway Inhibitors and Review of the Literature

Basal cell carcinoma is the most common skin tumour, with the majority of the cases occurring on the head and neck district, where cosmetic and functional results are crucial. It can be locally destructive if not diagnosed early and treated appropriately. Surgery is the treatment of choice for most lesions, but aggressive, recurrent, or unresectable tumours can be challenging to manage. Advanced basal cell carcinoma includes high recurrence risk subtypes, in which standard therapies demonstrate lack of efficacy. This led to a need for investigating more deeply the pathogenesis of the disease and to the discovery of the implication of the hedgehog pathway. The development of systemic inhibitors of this pathway provides new treatment options for patients with advanced disease, resulting in survival improvement. Food and Drug Administration, before, and European Medicines Agency later approved 2 Hedgehog pathway inhibitors for the treatment of advanced basal cell carcinomas, vismodegib and sonidegib. Here, we present a review of the current English language literature trying to analyze differences in the 2 drugs as a head-to-head comparison between them has not already been documented in a randomized controlled clinical trial. Although vismodegib and sonidegib showed similar efficacy and safety profiles, in an indirect comparison scenario, sonidegib has shown slightly better outcomes in locally advanced basal cell carcinoma than vismodegib. They present different molecular structures, as they bind different residues on their targets and develop resistance for different mutations. In a future scenario, clinical trials comparing the 2 drugs are needed, as well as expanding data on discontinuation of therapy and/or consequential administration of them, with the aim to improve our clinical practise.