Abstract 3227: Novel Marmelin analog DBQ targets Notch signaling pathway in colon cancer stem cells

Background: Colon cancer is the second leading cause of death in the United States. Previously, we have reported that the identification of a novel compound Marmelin from Aegle marmelos and potent anti-colon cancer activity. We have developed novel Marmelin analogue THB from this structure showed potent anti-cancer activity and its inhibitory constant value was 10 µM. From this, we developed a second series of analogs, of which DBQ is even more potent than THB. The current study is designed to determine whether DBQ affects colon cancer stem cells and identify a mechanism.

Method: Colon cancer cell lines HCT116 and SW480 and normal colon epithelial cells were used in the study. Cell growth was measured by hexoseaminidase and clonogenicity assays. Apoptosis was determined by measuring caspase 3/7 activities. Colosphere formation assay and FACS sorting were used for stem cells. For in vivo effects, we performed studies in HCT116 tumor xenografts. Immunohistochemistry was determined for stem cell markers and Notch signaling proteins.

Results: DBQ treatment induced significant dose-dependent inhibition of proliferation and colony formation of HCT116 and SW480 cells, but not that of the normal FHC colon epithelial cells. DBQ also significantly reduced the number and size of colospheres, suggesting effects on stem cells. In addition, DBQ reduced the levels of colon stem cell marker proteins DCLK1, LGR5, and CD44. We obtained further confirmation by flow cytometry, where DBQ treatment reduced the number of DCLK1+ cells. We next determined whether DBQ affects the Notch signaling, a pathway that is important in maintaining CSC population. Notch receptor and its ligands are up-regulated in human colon cancer tissues. DBQ treatment significantly downregulated the expression of all four Notch isoforms, its ligands Jagged 1, 2 and DLL1, 3, 4 and downstream target protein Hes1. Notch activation requires cleavage by the γ-secretase complex. DBQ treatment inhibits the expression of γ-secretase complex proteins. To confirm that DBQ effect is thorough downregulating Notch activation, we ectopically expressed the Notch Intracellular domain. DBQ effect was significantly mitigated in this condition. To determine the effect of DBQ on tumor growth in vivo, we administered DBQ intraperitoneally (5mg/kg bw) every day for 21 days in mice carrying HCT116 tumor xenografts. DBQ treatment significantly suppressed tumor xenograft growth, with notably lower tumor volume and weight. Western blot and immunohistochemistry analyses demonstrated significant inhibition of CSC marker proteins DCLK1, LGR5 and CD44 and also the Notch signaling proteins in the DBQ-treated xenograft tissues.

Conclusion: Together, these data suggest that DBQ treatment suppresses colon cancer growth that targets stem cells in part by inhibiting Notch signaling pathway.

Citation Format: Dharmalingam Subramaniam, Sivapriya Ponnurangam, Prasad R. Dandawate, Gaurav Kaushik, Ossama W. Tawfik, Roy A. Jensen, Santimukul Santra, Subhash B. Padhye, Scott J. Weir, Shrikant Anant. Novel Marmelin analog DBQ targets Notch signaling pathway in colon cancer stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3227. doi:10.1158/1538-7445.AM2017-3227

Quinomycin A targets Notch signaling pathway in pancreatic cancer stem cells

Cancer stem cells (CSCs) appear to explain many aspects of the neoplastic evolution of tumors and likely account for enhanced therapeutic resistance following treatment. Dysregulated Notch signaling, which affects CSCs plays an important role in pancreatic cancer progression. We have determined the ability of Quinomycin to inhibit CSCs and the Notch signaling pathway. Quinomycin treatment resulted in significant inhibition of proliferation and colony formation in pancreatic cancer cell lines, but not in normal pancreatic epithelial cells. Moreover, Quinomycin affected pancreatosphere formation. The compound also decreased the expression of CSC marker proteins DCLK1, CD44, CD24 and EPCAM. In addition, flow cytometry studies demonstrated that Quinomycin reduced the number of DCLK1+ cells. Furthermore, levels of Notch 1–4 receptors, their ligands Jagged1, Jagged2, DLL1, DLL3, DLL4 and the downstream target protein Hes-1 were reduced. The γ-secretase complex proteins, Presenilin 1, Nicastrin, Pen2, and APH-1, required for Notch activation also exhibited decreased expression. Ectopic expression of the Notch Intracellular Domain (NICD) partially rescued the cells from Quinomycin mediated growth suppression. To determine the effect of Quinomycin on tumor growth in vivo, nude mice carrying tumor xenografts were administered Quinomycin intraperitoneally every day for 21 days. Treatment with the compound significantly inhibited tumor xenograft growth, coupled with significant reduction in the expression of CSC markers and Notch signaling proteins. Together, these data suggest that Quinomycin is a potent inhibitor of pancreatic cancer that targets the stem cells by inhibiting Notch signaling proteins.

Bitter melon: a panacea for inflammation and cancer

Nature is a rich source of medicinal plants and their products that are useful for treatment of various diseases and disorders. Momordica charantia, commonly known as bitter melon or bitter gourd, is one of such plants known for its biological activities used in traditional system of medicines. This plant is cultivated in all over the world, including tropical areas of Asia, Amazon, east Africa, and the Caribbean and used as a vegetable as well as folk medicine. All parts of the plant, including the fruit, are commonly consumed and cooked with different vegetables, stir-fried, stuffed or used in small quantities in soups or beans to give a slightly bitter flavor and taste. The plant is reported to possess anti-oxidant, anti-inflammatory, anti-cancer, anti-diabetic, anti-bacterial, anti-obesity, and immunomodulatory activities. The plant extract inhibits cancer cell growth by inducing apoptosis, cell cycle arrest, autophagy and inhibiting cancer stem cells. The plant is rich in bioactive chemical constituents like cucurbitane type triterpenoids, triterpene glycosides, phenolic acids, flavonoids, essential oils, saponins, fatty acids, and proteins. Some of the isolated compounds (Kuguacin J, Karaviloside XI, Kuguaglycoside C, Momordicoside Q-U, Charantin, α-eleostearic acid) and proteins (α-Momorcharin, RNase MC2, MAP30) possess potent biological activity. In the present review, we are summarizing the anti-oxidant, anti-inflammatory, and anti-cancer activities of Momordica charantia along with a short account of important chemical constituents, providing a basis for establishing detail biological activities of the plant and developing novel drug molecules based on the active chemical constituents.

Targeting cancer stem cells and signaling pathways by phytochemicals: Novel approach for breast cancer therapy

Breast cancer is the most common form of cancer diagnosed in women worldwide and the second leading cause of cancer-related deaths in the USA. Despite the development of newer diagnostic methods, selective as well as targeted chemotherapies and their combinations, surgery, hormonal therapy, radiotherapy, breast cancer recurrence, metastasis and drug resistance are still the major problems for breast cancer. Emerging evidence suggest the existence of cancer stem cells (CSCs), a population of cells with the capacity to self-renew, differentiate and be capable of initiating and sustaining tumor growth. In addition, CSCs are believed to be responsible for cancer recurrence, anticancer drug resistance, and metastasis. Hence, compounds targeting breast CSCs may be better therapeutic agents for treating breast cancer and control recurrence and metastasis. Naturally occurring compounds, mainly phytochemicals have gained immense attention in recent times because of their wide safety profile, ability to target heterogeneous populations of cancer cells as well as CSCs, and their key signaling pathways. Therefore, in the present review article, we summarize our current understanding of breast CSCs and their signaling pathways, and the phytochemicals that affect these cells including curcumin, resveratrol, tea polyphenols (epigallocatechin-3-gallate, epigallocatechin), sulforaphane, genistein, indole-3-carbinol, 3, 3'-di-indolylmethane, vitamin E, retinoic acid, quercetin, parthenolide, triptolide, 6-shogaol, pterostilbene, isoliquiritigenin, celastrol, and koenimbin. These phytochemicals may serve as novel therapeutic agents for breast cancer treatment and future leads for drug development.

Abstract 4748: Targeting colon cancer stem cells: Novel marmelin analog THB suppresses DCLK1 and Notch Signaling

Background: Despite therapeutic advances, colon cancer remains the second leading cause of death in the United States. Previously, we have reported that the identification of a novel compound, HDNC or Marmelin from Aegle marmelos with potent anti-colon cancer activity. We have now developed a novel marmelin analogue THB and made it water soluble THB using β-cyclodextrin (THBCD). The current study is designed to determine whether THB affects stem cells and to identify a mechanism.

Method: Colon cancer cell lines HCT116 and SW480 and normal colon epithelial cells were used in the study. Cell growth was measured by hexoseaminidase and clonogenicity assays. Apoptosis was determined by measuring caspase 3/7 activities. Colosphere formation assay and FACS sorting were used for stem cells. For in vivo effects, we have performed HCT116 cells induced tumor xenografts. Immunohistochemistry was determined for stem cell markers and Notch signaling proteins.

Results: THB treatment induced a significant dose-dependent inhibition of proliferation and colony formation of the two colon cancer cell lines, but not that of the normal cells. To demonstrate THB effects on stem cells, we performed colosphere assays. THB treatment significantly reduced the number and size of colospheres, suggesting effects on stem cells. In addition, colon stem cell marker proteins DCLK1, LGR5, and CD44 were also decreased. Further proof was obtained by flow cytometry analyses, where THB reduced the number of DCLK1+ cells. We next determined whether THB affects the Notch signaling pathway, a pathway that is important in maintaining CSC population. Notch receptor and its ligands are up-regulated in human colon cancer tissues. THB treatment significantly downregulated the expression of Notch1, its ligand Jagged1 and downstream target protein Hes1. Notch activation requires cleavage by the γ-secretase complex. THB treatment inhibits the expression of γ-secretase complex proteins Presenilin1, Nicastrin, APH1 and PEN2. Moreover, ectopic expression of the Notch Intracellular domain (NICD) rescued the cells from THB mediated growth suppression. These data demonstrate that THB mediated effects of colon cancer stem cells is in part through downregulating Notch1 activation. To determine the effect of THB on tumor growth in vivo, mice carrying HCT116 tumor xenografts were administered the compound intraperitoneally (5mg/kg bw) every day for 21 days. THB treatment significantly suppressed tumor xenograft growth, with notably lower tumor volume and weight. Western blot and immunohistochemistry analyses demonstrated significant inhibition of CSC marker proteins DCLK1, LGR5 and CD44 and also the Notch signaling proteins in the THB-treated xenograft tissues.

Conclusion: Together, these data suggest that THB treatment suppresses colon cancer growth that targets stem cells by inhibiting Notch1 signaling pathway.

Citation Format: Dharmalingam Subramaniam, Sivapriya Ponnurangam, Prasad R. Dandawate, Ossama W. Tawfik, Roy A. Jensen, Scott J. Weir, Subhash B. Padhye, Shrikant Anant. Targeting colon cancer stem cells: Novel marmelin analog THB suppresses DCLK1 and Notch Signaling. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4748.

Effects of Combination of Thiazolidinediones with Melatonin in Dexamethasone-induced Insulin Resistance in Mice

In type 2 Diabetes, oxidative stress plays an important role in development and aggregation of insulin resistance. In the present study, long term administration of the dexamethasone led to the development of insulin resistance in mice. The effect of thiazolidinediones pioglitazone and rosiglitazone, with melatonin on dexamethasone-induced insulin resistance was evaluated in mice. Insulin resistant mice were treated with combination of pioglitazone (10 mg/kg/day, p.o.) or rosiglitazone (5 mg/kg/day, p.o.) with melatonin 10 mg/kg/day p.o. from day 7 to day 22. In the biochemical parameters, the serum glucose, triglyceride levels were significantly lowered (P<0.05) in the combination groups as compared to dexamethasone treated group as well as with individual groups of pioglitazone, rosiglitazone, and melatonin. There was also, significant increased (P<0.05) in the body weight gain in combination treated groups as compared to dexamethasone as well as individual groups. The combination groups proved to be effective in normalizing the levels of superoxide dismutase, catalase, glutathione reductase and lipid peroxidation in liver homogenates may be due to antioxidant effects of melatonin and decreased hyperglycemia induced insulin resistance by thiazolidinediones. The glucose uptake in the isolated hemidiaphragm of mice was significantly increased in combination treated groups (PM and RM) than dexamethasone alone treated mice as well as individual (pioglitazone, rosiglitazone, melatonin) treated groups probably via increased in expression of GLUT-4 by melatonin and thiazolidinediones as well as increased in insulin sensitivity by thiazolidinediones. Hence, it can be concluded that combination of pioglitazone and rosiglitazone, thiazolidinediones, with melatonin may reduces the insulin resistance via decreased in oxidative stress and control on hyperglycemia.

Inclusion complex of novel curcumin analogue CDF and β-cyclodextrin (1:2) and its enhanced in vivo anticancer activity against pancreatic cancer

PURPOSE

Several formulations have been proposed to improve the systemic delivery of novel cancer therapeutic compounds, including cyclodextrin derivatives. We aimed to synthesize and characterize of CDF-β-cyclodextrin inclusion complex (1:2) (CDFCD).

METHODS

The compound was characterized by Fourier transform infrared, differential scanning calorimetry, powder X-ray diffraction studies, H1 & C13 NMR studies and scanning electron microscopic analysis. Its activity was tested against multiple cancer cell lines, and in vivo bioavailability was checked.

RESULTS

CDF-β-cyclodextrin was found to lower IC(50) value by half when tested against multiple cancer cell lines. It preferentially accumulated in the pancreas, where levels of CDF-β-cyclodextrin in mice were 10 times higher than in serum, following intravenous administration of an aqueous CDF-β-cyclodextrin preparation.

CONCLUSIONS

Novel curcumin analog CDF preferentially accumulates in the pancreas, leading to its potent anticancer activity against pancreatic cancer cells. Synthesis of such CDF-β-cyclodextrin self-assembly is an effective strategy to enhance its bioavailability and tissue distribution, warranting further evaluation for CDF delivery in clinical settings for treatment of human malignancies.

Transition metal complexes of 3-aryl-2-substituted 1,2-dihydroquinazolin-4(3H)-one derivatives: new class of analgesic and anti-inflammatory agents

Five-coordinate, neutral transition metal complexes of newly designed pyridine-2-ethyl-(3-carboxylideneamino)-3-(2-phenyl)-1,2-dihydroquinazolin-4(3H)-one (L) were synthesized and characterized. The structure of ligand is confirmed by single crystal X-ray diffraction studies. The compounds were evaluated for the anti-inflammatory activity by carrageenan-induced rat paw edema model while their analgesic activity was determined by acetic acid-induced writhing test in mice wherein the transition metal complexes were found to be more active than the free ligand.