Cucurbitacin B and I inhibits colon cancer growth by targeting the Notch signaling pathway

Abstract

cancer stem cells (cScs) have the ability to self-renew and induce drug resistance and recurrence in colorectal cancer (cRc). As current chemotherapy doesn't eliminate cScs completely, there is a need to identify novel agents to target them. We investigated the effects of cucurbitacin B (C-B) or I (C-I), a natural compound that exists in edible plants (bitter melons, cucumbers, pumpkins and zucchini), against cRc. c-B or c-i inhibited proliferation, clonogenicity, induced G 2 /M cell-cycle arrest and caspase-mediated-apoptosis of cRc cells. c-B or c-i suppressed colonosphere formation and inhibited expression of CD44, DCLK1 and LGR5. These compounds inhibited notch signaling by reducing the expression of Notch 1-4 receptors, their ligands (Jagged 1-2, DLL1,3,4), γ-secretase complex proteins (Presenilin 1, Nicastrin), and downstream target Hes-1. Molecular docking showed that C-B or C-I binds to the ankyrin domain of Notch receptor, which was confirmed using the cellular thermal shift assay. finally, c-B or c-i inhibited tumor xenograft growth in nude mice and decreased the expression of cScmarkers and notch signaling proteins in tumor tissues. together, our study suggests that c-B and c-i inhibit colon cancer growth by inhibiting notch signaling pathway. Colorectal cancer (CRC) is the third most commonly diagnosed cancer with an estimated 145600 new cases and 51020 deaths estimated to occur in the United States in 2019 1. A significant concern is that the frequency of individuals diagnosed with colon cancer below 50 years of age is steadily rising every year 2. Adjuvant chemotherapy and radiotherapy post-surgery is the primary choice of treatment for advanced CRC 3. Cancer stem cells (CSCs) are rare in number and possess the ability to self-renew with the capacity to generate a tumor 4,5. They also develop chemo-and radio-resistance, contributing to tumor progression and recurrence. As current chemotherapy is not able to achieve complete eradication of CSCs 6 , it is crucial to develop novel non-toxic drug therapies that effectively target both CSCs and proliferating cancer cells. CSC markers identified in CRC, include CD44, leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5), c-Myc, ABCG2, CD133, ALDH1A1, epithelial cell adhesion molecule (EpCAM) and doublecortin-like kinase-1 (DCLK1) 7. CSCs rely on classic signaling pathways for growth such as the Notch signaling that plays an important role in transformation and CSC self-renewal 8. The Notch pathway consists of five ligands (Jagged-1, Jagged-2 and Delta-like ligands −1, −3 and −4 (Dll-1, −3 and −4) and four receptors (Notch 1-4) 9. Upon ligand binding, Notch receptors are cleaved twice. The first cleavage by ADAM/TACE is followed by a second cleavage by the γ-secretase enzyme complex releasing Notch intracellular domain (NICD). The NICD binds to MAML1-CSL-HAT-P300 complex to induce the target gene expression including but not limited to HES1, HEY1, Cyclin D1 and c-Myc 9. Hence, targeting the Notch signaling pathway may be an effective mechanism...

Sorafenib and CuB exert synergistic antitumor effects against hepatocellular carcinoma cells via inhibition of STAT3 phosphorylation

“…For example, CuB tablets could be used for the treatment of chronic hepatitis in China [13]. It is noteworthy that the antitumor activity of CuB was widely reported in a variety of cancers, including liver cancer, lung cancer, skin cancer, colorectal cancer, breast cancer [14], laryngeal squamous cell carcinoma [15], osteosarcoma [16] and pancreatic cancer [17]. Previous studies have shown that the antitumor effects can be enhanced further when CuB is combined with curcumin in hepatoma cells [18] and also when CuB is combined with gefitinib in human colorectal cancer cell [19].…”

Identification prognosis-associated immune genes in colon adenocarcinoma

“…The blockade of PD-L1 increased FABP4 expression in tissue-resident memory T (Trm) cells, promoting lipid uptake by Trm cells [ 50 ]. Previous reports indicate that the hedgehog signaling pathway might affect the recurrence of COAD patients [ 51 ]. Dandawate et al reported that the Notch signaling pathway involved regulating colon cancer cells’ proliferation [ 51 ].…”

“…Previous reports indicate that the hedgehog signaling pathway might affect the recurrence of COAD patients [ 51 ]. Dandawate et al reported that the Notch signaling pathway involved regulating colon cancer cells’ proliferation [ 51 ]. Our results are consistent with these reports.…”

Cucurbitacins: A Focus on Cucurbitacin E As A Natural Product and Their Biological Activities

“…Also, tumor growth can inhibits by CuB in a dose-dependent way in Hep-2 cells and in vivo researches in a mouse xenograft model. 68 23, 24-Dihydrocucurbitacin B, found to inhibit the proliferation of HeLa, Bcap37, SMMC-7721, K562 SW620 and MCF-7, human cancer cell lines and induce apoptosis in Bcap37 human breast cancer cell line. DHCB induces Bcap37 apoptosis through mitochondrial dependent pathway and stopping induction of G2/M phase in cell-cycle as well.…”