Differential regulation of MMP7 in colon cancer cells resistant and sensitive to oxaliplatin-induced cell death

Preclinical Identification of Sulfasalazine’s Therapeutic Potential for Suppressing Colorectal Cancer Stemness and Metastasis through Targeting KRAS/MMP7/CD44 Signaling

Approximately 25% of colorectal cancer (CRC) patients will develop metastatic (m)CRC despite treatment interventions. In this setting, tumor cells are attracted to the epidermal growth factor receptor (EGFR) oncogene. Kirsten rat sarcoma (RAS) 2 viral oncogene homolog (KRAS) mutations were reported to drive CRC by promoting cancer progression in activating Wnt/β-catenin and RAS/extracellular signal-regulated kinase (ERK) pathways. In addition, KRAS is associated with almost 40% of patients who acquire resistance to EGFR inhibitors in mCRC. Multiple studies have demonstrated that cancer stem cells (CSCs) promote tumorigenesis, tumor growth, and resistance to therapy. One of the most common CSC prognostic markers widely reported in CRC is a cluster of differentiation 44 (CD44), which regulates matrix metalloproteinases 7/9 (MMP7/9) to promote tumor progression and metastasis; however, the molecular role of CD44 in CRC is still unclear. In invasive CRC, overexpression of MMP7 was reported in tumor cells compared to normal cells and plays a crucial function in CRC cetuximab and oxaliplatin resistance and distant metastasis. Here, we utilized a bioinformatics analysis and identified overexpression of KRAS/MMP7/CD44 oncogenic signatures in CRC tumor tissues compared to normal tissues. In addition, a high incidence of mutations in KRAS and CD44 were associated with some of the top tumorigenic oncogene’s overexpression, which ultimately promoted a poor response to chemotherapy and resistance to some FDA-approved drugs. Based on these findings, we explored a computational approach to drug repurposing of the drug, sulfasalazine, and our in silico molecular docking revealed unique interactions of sulfasalazine with the KRAS/MMP7/CD44 oncogenes, resulting in high binding affinities compared to those of standard inhibitors. Our in vitro analysis demonstrated that sulfasalazine combined with cisplatin reduced cell viability, colony, and sphere formation in CRC cell lines. In addition, sulfasalazine alone and combined with cisplatin suppressed the expression of KRAS/MMP7/CD44 in DLD-1 and HCT116 cell lines. Thus, sulfasalazine is worthy of further investigation as an adjuvant agent for improving chemotherapeutic responses in CRC patients.

LEF1 silencing sensitizes colorectal cancer cells to oxaliplatin, 5-FU, and irinotecan

Colorectal cancer (CRC) is the third most prevalent cancer all around the world. Chemotherapy plays an essential role in the treatment of CRC while Oxaliplatin, Irinotecan, and 5 - fluorouracil (5-FU) are the most commonly used chemotherapeutic drugs. However, chemo-resistance is a major obstacle to successful therapy. It has been shown that inhibition of Wnt signaling pathway can sensitize the cells to chemotherapy. Lymphoid enhancer factor (LEF1) is a member of TCF/LEF transcription family mediating Wnt nuclear responses. The long isoform of LEF1 is highly expressed in colorectal cancer cells compared to the normal intestinal cells, in which expression of the short isoform is dominant. We found that the downregulation of long isoforms of LEF1 makes CRC cell lines more sensitive to the effect of chemotherapeutic drugs. This sensitivity is imposed by reduced proliferation, increased apoptosis, or cell cycle arrest. Our results also demonstrated that there is a balance in the expression of long, and short isoforms of LEF1. In summary, we showed the role of LEF1 in chemo-resistance of colorectal cancer cells to Oxaliplatin, Irinotecan and 5-FU.

Sensitization of EGFR Wild-Type Non-Small Cell Lung Cancer Cells to EGFR-Tyrosine Kinase Inhibitor Erlotinib

The benefit of EGFR-TKI in non-small cell lung cancer has been demonstrated in mutant EGFR tumors as first-line treatment but the benefit in wild-type EGFR tumors is marginal as well as restricted to maintenance therapy in pretreated patients. This work aimed at questioning the effects of cisplatin initial treatment on the EGFR pathway in non-small cell lung cancer and the functional consequences in vitro and in in vivo animal models of patient-derived xenografts (PDX). We establish here that cisplatin pretreatment specifically sensitizes wild-type EGFR-expressing cells to erlotinib, contrary to what happens in mutant EGFR cells and with a blocking EGFR antibody, both in vitro and in vivo The sensitization entails the activation of the kinase Src upstream of EGFR, thereafter transactivating EGFR through a ligand-independent activation. We propose a combination of markers that enable to discriminate between the tumors sensitized to erlotinib or not in PDX models, which should be worth testing in patients. These markers might be useful for the selection of patients who would benefit from erlotinib as a maintenance therapy. Mol Cancer Ther; 16(8); 1634-44. ©2017 AACR.

Targeting the Fas/FasL signaling pathway in cancer therapy

INTRODUCTION

The Fas/FasL system plays a significant role in tumorigenesis. Research has shown that its impairment in cancer cells may lead to apoptosis resistance and contribute to tumor progression. Thus, the development of effective therapies targeting the Fas/FasL system may play an important role in the fight against cancer.

AREAS COVERED

In this review the recent literature on targeting the Fas/FasL system for therapeutic exploitation at different levels is reviewed. Promising pre-clinical approaches and various exceptions are highlighted. The potential of combined therapies is also explored, whereby tumor sensitivity to Fas-mediated apoptosis is restored, before an effective targeted therapy is employed.

EXPERT OPINION

The success of the Fas/FasL system targeting for therapeutics will require a better understanding of the alterations conferring resistance, in order to use the most appropriate sensitizing chemotherapeutic or radiotherapeutic agents in combination with effective targeted therapies.

Antisense oligonucleotide targeting matrix metalloproteinase-7 (MMP-7) changes the ultrastructure of human A549 lung adenocarcinoma cells

Antisense oligonucleotide (ASODN) targeting specific gene can be capable of potently downregulating proliferation and invasion in human cancer cells. However, the underlying mechanisms are less well defined. Here the authors show that matrix metalloproteinase-7 (MMP-7) ASODN changes the ultrastructure of human A549 lung adenocarcinoma cells. Transfection of MMP-7 ASODN significantly lowered the expression of MMP-7 protein in A549 cells. Decreased microvilli, endoplasmic reticulum dilation, swelling of mitochondria, and formation of apoptotic bodies were observed by transmission electron microscope. Collectively, the findings identified the morphological mechanism that MMP-7 ASODN inhibited proliferation and invasion in A549 cells.