Chemoprevention of colon cancer in a rat carcinogenesis model using a novel nanotechnology-based combined treatment system

Non-steroidal anti-inflammatory drugs and biomarkers: A new paradigm in colorectal cancer

Colorectal cancer is a sporadic, hereditary, or familial based disease in its origin, caused due to diverse set of mutations in large intestinal epithelial cells. Colorectal cancer (CRC) is a common and deadly disease that accounts for the 4^th worldwide highly variable malignancy. For the early detection of CRC, the most common predictive biomarker found endogenously are KRAS and ctDNA/cfDNA along with SEPT9 methylated DNA. Early detection and screening for CRC are necessary and multiple methods can be employed to screen and perform early diagnosis of CRC. Colonoscopy, an invasive method is most prevalent for diagnosing CRC or confirming the positive result as compared to other screening methods whereas several non-invasive techniques such as molecular analysis of breath, urine, blood, and stool can also be performed for early detection. Interestingly, widely used medicines known as non-steroidal anti-inflammatory drugs (NSAIDs) to reduce pain and inflammation have reported chemopreventive impact on gastrointestinal malignancies, especially CRC in several epidemiological and preclinical types of research. NSAID acts by inhibiting two cyclooxygenase enzymes, thereby preventing the synthesis of prostaglandins (PGs) and causing NSAID-induced apoptosis and growth inhibition in CRC cells. This review paper majorly focuses on the diversity of natural and synthetic biomarkers and various techniques for the early detection of CRC. An approach toward current advancement in CRC detection techniques and the role of NSAIDs in CRC chemoprevention has been explored systematically. Several prominent governing mechanisms of the anti-cancer effects of NSAIDs and their synergistic effect with statins for an effective chemopreventive measure have also been discussed in this review paper.

Doxorubicin-Loaded Tumor-Targeting Peptide-Decorated Polypeptide Nanoparticles for Treating Primary Orthotopic Colon Cancer

Colorectal cancer is the third most common malignant disease worldwide, and chemotherapy has been the standard treatment for colorectal cancer. However, the therapeutic effects of chemotherapy are unsatisfactory for advanced and recurrent colorectal cancers. Thus, increasing the treatment efficacy of chemotherapy in colorectal cancer is a must. In this study, doxorubicin (DOX)-loaded tumor-targeting peptide-decorated mPEG-P(Phe-co-Cys) nanoparticles were developed to treat orthotopic colon cancer in mice. The peptide VATANST (STP) can specifically bind with vimentin highly expressed on the surface of colon cancer cells, thus achieving the tumor-targeting effects. The nanoparticles are core-shell structured, which can protect the loaded DOX while passing through the blood flow and increase the circulation time. The disulfide bonds within the nanoparticles are sensitive to the glutathione-rich microenvironment of tumor tissues. Rupture of disulfide bonds of the nanoparticles leads to the continuous release of DOX, thus resulting in the apoptosis of the tumor cells. The in vivo experiments in mice with orthotopic colon cancer demonstrated that the synthesized DOX-loaded tumor-targeting peptide-decorated polypeptide nanoparticles showed properties of drug delivery systems and exhibited good antitumor properties. The synthesized nanoparticles show appropriate properties as one of the drug delivery systems and exhibit good antitumor properties after encapsulating DOX.

Microenvironmental Reactive Oxygen Species in Colorectal Cancer: Involved Processes and Therapeutic Opportunities

Colorectal cancer (CRC) is the fourth most common cause of cancer deaths worldwide. Although screening programs have reduced mortality rates, there is a need for research focused on finding the main factors that lead primary CRC to progress and metastasize. During tumor progression, malignant cells modify their habitat, corrupting or transforming cells of different origins and creating the tumor microenvironment (TME). Cells forming the TME like macrophages, neutrophils, and fibroblasts generate reactive oxygen species (ROS) that modify the cancer niche. The effects of ROS in cancer are very diverse: they promote cellular proliferation, epithelial-to-mesenchymal transition (EMT), evasion of cell death programs, migration, and angiogenesis. Due to the multifaceted role of ROS in cancer cell survival and function, ROS-modulating agents such as antioxidants or pro-oxidants could have therapeutic potential in cancer prevention and/or as a complement to systemic treatments. In this review, we will examine the main ROS producer cells and their effects on cancer progression and metastasis. Furthermore, we will enumerate the latest clinical trials where pro-oxidants and antioxidants have therapeutic uses in CRC.

Nanotechnology in Colorectal Cancer for Precision Diagnosis and Therapy

Colorectal cancer (CRC) is the third most frequently occurring tumor in the human population. CRCs are usually adenocarcinomatous and originate as a polyp on the inner wall of the colon or rectum which may become malignant in the due course of time. Although the therapeutic options of CRC are limited, the early diagnosis of CRC may play an important role in preventive and therapeutic interventions to decrease the mortality rate. The CRC-affected tissues exhibit several molecular markers that may be exploited as the novel strategy to develop newer approaches for the treatment of the disease. Nanotechnology consists of a wide array of innovative and astonishing nanomaterials with both diagnostics and therapeutic potential. Several nanomaterials and nano formulations such as Carbon nanotubes, Dendrimer, Liposomes, Silica Nanoparticles, Gold nanoparticles, Metal-organic frameworks, Core-shell polymeric nano-formulations, Nano-emulsion System, etc can be used to targeted anticancer drug delivery and diagnostic purposes in CRC. The light-sensitive photosensitizer drugs loaded gold and silica nanoparticles can be used to diagnose as well as the killing of CRC cells by the targeted delivery of anticancer drugs to cancer cells. This review is focused on the recent advancement of nanotechnology in the diagnosis and treatment of CRC.

The immunomodulatory effects of topiramate on azoxymethane-induced colon carcinogenesis in rats: The role of the inflammatory cascade, vascular endothelial growth factor, AKT/mTOR/MAP kinase signaling and the apoptotic markers

BACKGROUND

Colon cancer is a malignant condition that affects the lower gastrointestinal tract and has unfavorable prognosis. Its mechanisms range from enhanced production of reactive oxygen species, inflammatory changes in the colon microenvironment and affection of the apoptotic pathways. Due to the high incidence of resistance of colon cancer to the traditional chemotherapeutic agents, a need for finding safe/effective agents that can attenuate the malignant changes had emerged.

OBJECTIVE

To investigate the possible immunomodulatory and antitumor effects of topiramate on azoxymethane-induced colon cancer in rats.

METHODOLOGY

Fifty male Wistar rats were randomized into five equal groups as follows: Control; azoxymethane-induced colon cancer; azoxymethane + methyl cellulose; azoxymethane + topiramate small dose; and azoxymethane + topiramate large dose. The body weight gain, serum carcinoembryonic antigen (CEA), tissue antioxidant status, proinflammatory cytokines, vascular endothelial growth factor (VEGF), Nrf2/HO-1 content, p-AKT, mTOR, p38 MAP kinase, caspase 9, nerve growth factor beta and beclin-1 were measured. Also, parts of the colon had undergone histopathological and immunohistochemical evaluation.

KEY FINDINGS

Topiramate improved the body weight gain, decreased serum CEA, augmented the antioxidant defenses in the colonic tissues with significant amelioration of the inflammatory changes, decline in tissue VEGF and p-AKT/mTOR/MAP kinase signaling and increased Nrf2/HO-1 content in a dose-dependent manner when compared to rats treated with azoxymethane alone. In addition, topiramate, in a dose-dependent manner, significantly enhanced apoptosis and improved the histopathological picture in comparison to animals treated with azoxymethane alone.

CONCLUSION

Taking these findings together, topiramate might serve as a new effective adjuvant line of treatment of colon cancer.

Triumph against cancer: invading colorectal cancer with nanotechnology

INTRODUCTION

Recent statistics have reported colorectal cancer (CRC) as the second leading cause of cancer-associated deaths in the world. Early diagnosis of CRC may help to reduce the mortality and associated complications. However, the conventional diagnostic techniques often lead to misdiagnosis, fail to differentiate benign from malignant tissue or diagnose only at an advanced stage. For the treatment of CRC, surgery, chemotherapy, immunotherapy, and radiotherapy have been employed. However, the quality of living of the CRC patients is highly compromised after employing current therapeutic approaches owing to the toxicity issues and relapse.

AREA COVERED

This review accentuates the molecular mechanisms involved in the pathogenesis, stages of CRC, conventional approaches for diagnosis and therapy of CRC and the issues confronted thereby. It provides an outlook on the advantages of employing nanotechnology-based approaches for prevention, early diagnosis, and treatment of CRC.

EXPERT OPINION

Employing nanotechnology-based approaches has demonstrated promising outcomes in the prevention, diagnosis, and treatment of CRC. Nanotechnology-based approaches can surmount the major drawbacks of traditional diagnostic and therapeutic approaches. Nanotechnology bestows the advantage of early detection of CRC which helps to undertake instant steps for offering efficient therapy and reducing the mortality rates. For the treatment of CRC, nanocarriers offer the benefit of achieving controlled drug release, improved drug bioavailability, enhanced tumor targetability and reduced adverse effects.

Cancer Chemoprevention Using Nanotechnology-Based Approaches

Cancer research in pursuit of better diagnostic and treatment modalities has seen great advances in recent years. However, the incidence rate of cancer is still very high. Almost 40% of women and men are diagnosed with cancer during their lifetime. Such high incidence has not only resulted in high mortality but also severely compromised patient lifestyles, and added a great socioeconomic burden. In view of this, chemoprevention has gained wide attention as a method to reduce cancer incidence and its relapse after treatment. Among various stems of chemoprevention research, nanotechnology-based chemoprevention approaches have established their potential to offer better efficacy and safety. This review summarizes recent advances in nanotechnology-based chemoprevention strategies for various cancers with emphasis on lung and bronchial cancer, colorectal, pancreatic, and breast cancer and highlights the unmet needs in this developing field towards successful clinical translation.

Synergistic anticancer effects of curcumin and 3',4'-didemethylnobiletin in combination on colon cancer cells

Chemoprevention strategies employing the use of multiple dietary bioactive components and their metabolites in combination offer advantages due to their low toxicity and potential synergistic interactions. Herein, for the first time, we studied the combination of curcumin and 3',4'-didemethylnobiletin (DDMN), a primary metabolite of nobiletin, to determine their combinatory effects in inhibiting growth of human colon cancer cells. Isobologram analysis revealed a synergistic interaction between curcumin and DDMN in the inhibition of cell growth of HCT116 colon cancer cells. The combination treatment induced significant G₂ -M cell-cycle arrest and extensive apoptosis, which greatly exceeded the effects of individual treatments with curcumin or DDMN. Proteins associated with these heightened anticarcinogenic effects were p53, p21, HO-1, c-poly(ADP-ribose) polymerase, Cdc2, and Cdc25c; each of the proteins was confirmed to be substantially impacted by the combination treatment, more than by individual treatments alone. Interestingly, an increase in the stability of curcumin was also observed with the presence of DDMN in cell culture medium, which could offer an explanation in part for the synergistic interaction between curcumin and DDMN. This newly identified synergy between curcumin and DDMN should be explored further to determine its chemopreventive potential against colon cancer in vivo. PRACTICAL APPLICATION: This study identifies for the first time the synergistic inhibition of colon cancer cell growth by the dietary component curcumin present in turmeric, in combination with a metabolite of nobiletin, a unique citrus flavonoid. The synergism of the combination may be due to cell-cycle arrest and apoptosis induced by the combination as well as an improvement in the stability of curcumin as a result of the antioxidant property of the nobiletin metabolite. These significant findings of synergism between curcumin and the nobiletin metabolite could offer potential chemopreventive value against colon cancer.

Novel nano-drug combination therapeutic regimen demonstrates significant efficacy in the transgenic mouse model of pancreatic ductal adenocarcinoma

The current work studied the chemopreventive efficacy of orally administered chitosan coated solid-lipid nanoparticle (c-SLN) encapsulated aspirin (ASP), curcumin (CUR) and free sulforaphane (SFN), ACS-cSLN, in the LSL-Kras ^G12D/+; Pdx-1 ^Cre/+ transgenic mouse model of pancreatic ductal adenocarcinoma (PDAC). In vitro uptake study and intracellular localization of ODA-FITC labeled ASP and CUR c-SLNs were performed in Panc-1 and MIA PaCa-2 cells by fluorescence microscopy. LSL-Kras ^G12D/+; Pdx-1 ^Cre/+ transgenic mice (n = 30) were randomly divided into 5 groups. Treatment groups were orally gavaged with ACS c-SLNs in three doses: low (2 + 4.5 + 0.16 mg/kg), medium (20 + 45 + 1.6 mg/kg) and high (60 + 135 + 4.8 mg/kg), respectively. After 20 weeks of treatment, mice pancreas were harvested, stained with dye and scored according to various pancreatic intraepithelial neoplasms (PanIN) categories by an independent observer. In vitro, cellular uptake evaluated on Panc-1 and MIA PaCa-2 cells resulted in higher fluorescence intensities, indicating increased cellular uptake of ASP and CUR c-SLNs. For further evidence, the addition of lysoID (red fluorescence) demonstrated location and uptake of ASP and CUR c-SLNs into the lysosome. In vivo, treatment with ACS c-SLN for 20-weeks did not cause obvious adverse effects on growth and no statistically significant differences in body weight were observed between groups. However, the weight (mean ± SEM) of pancreas at the end of the study was higher in blank c-SLN group (223.6 ± 42.2 mg) compared to low (138.0 ± 26.0 mg; not significant [NS]), medium (145.0 ± 9.0 mg; NS), and high (133.8 ± 20.3 mg; NS) ACS c-SLN treated groups, demonstrating the efficacy of ACS c-SLN nanoformulations. The low, medium and high dose of ACS c-SLN combinations exhibited a reduction in tumor incidence (PanIN count) by 16.6% (P < 0.01), 66.8% (P < 0.01), and 83.4% (P < 0.01), respectively. These studies provide further proof for the use of an oral, low dose nanotechnology-based combinatorial regimen for the chemoprevention of PDAC.

A novel nanomissile targeting two biomarkers and accurately bombing CTCs with doxorubicin

Rare circulating tumor cells (CTCs) cause >50% of primary colorectal cancer survivors to develop deadly metastasis at 3-5 years after surgery; the current chemotherapies can do nothing about these cells. Herein, we synthesized a novel doxorubicin (DOX)-entrapped mesoporous silica nanoparticle (MSN), covalently-conjugated with two aptamers, for simultaneously targeting EpCAM and CD44, the typical surface biomarkers of colorectal CTCs. The nanomissile can specifically capture the metastasis-prone CTCs spiked in healthy human blood in a competitive-binding manner. The binding not only accurately delivers DOX into the cancer cells via the biomarker-mediated endocytosis to inhibit CTC viability through the DOX-dependent mechanism, but also inhibits the adhesion of cancer cells to the endothelium and the consequent transmembrane migration through the DOX-independent mechanism. The molecular entity of the conjugate and its pharmaceutical DOX encapsulation-releasing capacity are well-demonstrated via various physiochemical characterizations including gel electrophoresis, which proves the >8-hour biostability of the nanomissile in blood, long enough for it to chase CTCs in mice and synergistically inhibit the CTC-induced lung metastasis more potently than its single aptamer-conjugated counterparts and DOX itself. The present strategy may pave a new avenue for safe and effective cancer metastasis chemoprevention.

Ferulic acid combined with aspirin demonstrates chemopreventive potential towards pancreatic cancer when delivered using chitosan-coated solid-lipid nanoparticles

BACKGROUND

The overall goal of this study was to demonstrate potential chemopreventive effects of ferulic acid (FA), an antioxidant, combined with aspirin (ASP), a commonly used anti-inflammatory drug for pancreatic cancer chemoprevention, using a novel chitosan-coated solid lipid nanoparticles (c-SLN) drug delivery system encapsulating FA and ASP.

RESULTS

Our formulation optimization results showed that c-SLNs of FA and ASP exhibited appropriate initial particle sizes in range of 183 ± 46 and 229 ± 67 nm, encapsulation efficiency of 80 and 78 %, and zeta potential of 39.1 and 50.3 mV, respectively. In vitro studies were conducted to measure growth inhibition and degree of apoptotic cell death induced by either FA or ASP alone or in combination. Cell viability studies demonstrated combinations of low doses of free FA (200 µM) and ASP (1 mM) significantly reduced cell viability by 45 and 60 % in human pancreatic cancer cells MIA PaCa-2 and Panc-1, respectively. However, when encapsulated within c-SLNs, a 5- and 40-fold decreases in dose of FA (40 µM) and ASP (25 µM) was observed which was significant. Furthermore, increased apoptosis of 35 and 31 % was observed in MIA PaCa-2 and Panc-1 cells, respectively. In vivo studies using oral administration of combinations of 75 and 25 mg/kg of FA and ASP c-SLNs to MIA PaCa-2 pancreatic tumor xenograft mice model suppressed the growth of the tumor by 45 % compared to control, although this was not statistically significant. In addition, the immunohistochemical analysis of tumor tissue showed significant decrease in expression of proliferation proteins PCNA and MKI67, and also increased expression of apoptotic proteins p-RB, p21, and p-ERK1/2 indicating the pro-apoptotic role of the regimen.

CONCLUSION

Combination of FA and ASP delivered via a novel nanotechnology-based c-SLN formulation demonstrates potential for pancreatic cancer chemoprevention and could be a promising area for future studies.

Convergence of nanotechnology and cancer prevention: are we there yet?

Nanotechnology is emerging as a promising modality for cancer treatment; however, in the realm of cancer prevention, its full utility has yet to be determined. Here, we discuss the potential of integrating nanotechnology in cancer prevention to augment early diagnosis, precision targeting, and controlled release of chemopreventive agents, reduced toxicity, risk/response assessment, and personalized point-of-care monitoring. Cancer is a multistep, progressive disease; the functional and acquired characteristics of the early precancer phenotype are intrinsically different from those of a more advanced anaplastic or invasive malignancy. Therefore, applying nanotechnology to precancers is likely to be far more challenging than applying it to established disease. Frank cancers are more readily identifiable through imaging and biomarker and histopathologic assessment than their precancerous precursors. In addition, prevention subjects routinely have more rigorous intervention criteria than therapy subjects. Any nanopreventive agent developed to prevent sporadic cancers found in the general population must exhibit a very low risk of serious side effects. In contrast, a greater risk of side effects might be more acceptable in subjects at high risk for cancer. Using nanotechnology to prevent cancer is an aspirational goal, but clearly identifying the intermediate objectives and potential barriers is an essential first step in this exciting journey.

A novel combinatorial nanotechnology-based oral chemopreventive regimen demonstrates significant suppression of pancreatic cancer neoplastic lesions

Pancreatic cancer is a deadly disease killing 37,000 Americans each year. Despite two decades of research on treatment options, the chances of survival are still less than 5% upon diagnosis. Recently, chemopreventive strategies have gained considerable attention as an alternative to treatment. We have previously shown significant in vitro chemopreventive effects with low-dose combinations of aspirin, curcumin, and sulforaphane (ACS) on pancreatic cancer cell lines. Here, we report the results of 24-week chemopreventive study with the oral administration of ACS combinations on the N-nitrosobis (2-oxopropyl) amine (BOP)-treated Syrian golden hamster model to suppress the progression of pancreatic intraepithelial neoplasms (PanIN) using unmodified (free drug) combinations of ACS, and nanoencapsulated (solid lipid nanoparticles; SLN) combinations of aspirin, curcumin, and free sulforaphane. The use of three different doses (low, medium, and high) of unmodified ACS combinations exhibited reduction in tumor incidence by 18%, 50%, and 68.7% respectively; whereas the modified nanoencapsulated ACS regimens reduced tumor incidence by 33%, 67%, and 75%, respectively, at 10 times lower dose compared with the free drug combinations. Similarly, although the unmodified free ACS showed a notable reduction in cell proliferation, the SLN encapsulated ACS regimens showed significant reduction in cell proliferation at 6.3%, 58.6%, and 72.8% as evidenced by proliferating cell nuclear antigen expression. Cell apoptotic indices were also upregulated by 1.5, 2.8, and 3.2 times, respectively, compared with BOP control. These studies provide a proof-of-concept for the use of an oral, low-dose, nanotechnology-based combinatorial regimen for the long-term chemoprevention of pancreatic cancer.

Big punches come in nanosizes for chemoprevention

Literature to support the chemopreventive potential of several bioactive molecules has been prolific and convincing, but the clinical development of these agents has been slow. Major hurdles for development of bioactive chemoprevention approaches include low potency, lack of reliable formulations with high bioavailability that are suitable for oral administration, and relevant preclinical primary prevention models that use meaningful doses that can be translated to humans. The paper presented in this issue (Grandhi and colleagues) is an important step forward in this direction. It shows the efficacy of an oral, low dose, solid-lipid nanoparticles encapsulated curcumin and aspirin combined with free sulforaphane for long-term chemoprevention of pancreatic cancer in a carcinogen-induced hamster model. Reproducing this benefit in multiple cancer models, accompanied by development of intermediate markers of response will allow rapid translation of these findings. It will constitute the first successful multipronged attack at key pathways known to initiate and promote carcinogenesis.

The molecular mechanism of action of aspirin, curcumin and sulforaphane combinations in the chemoprevention of pancreatic cancer

Pancreatic cancer ranks as the fourth most deadly form of cancer in the United States with ~37,000 deaths each year. The present study evaluated the chemopreventive potential of a combination of aspirin (ASP), curcumin (CUR) and sulforaphane (SFN) in low doses to human pancreatic cancer cells, MIA PaCa-2 and Panc-1. Results demonstrated that low doses of ASP (1 mM), CUR (10 μM) and SFN (5 μM) (ACS) combination reduced cell viability by ~70% (P<0.001), and also induced cell apoptosis by ~51% (P<0.001) accompanied by activation of caspase-3 and Poly(ADP-ribose) polymerase (PARP) proteins. The NF-κB DNA binding activity was inhibited by ~45% (P<0.01) and ~75% (P<0.001) in MIA PaCa-2 and Panc-1 cells, respectively. Mechanistic studies revealed that ACS promoted increase expression of phospho extracellular signal-regulated kinase 1/2 (P-ERK1/2), c-Jun, p38 MAPK and p53 proteins. Furthermore, the cells pretreated with U0126 (ERK1/2 inhibitor) partially abolished the effect of ACS on cell viability. Data from this study demonstrate that a low-dose ACS combination inhibits cell growth by inducing cell apoptosis, and proposes sustained activation of the ERK1/2 signaling pathway as one of the possible mechanisms.

Chemoprevention of pancreatic cancer using solid-lipid nanoparticulate delivery of a novel aspirin, curcumin and sulforaphane drug combination regimen

Pancreatic cancer is the fourth largest cause of cancer deaths in the Unites States and the prognosis is grim with <5% survival chances upon diagnosis. The objective of this study was to assess the combined chemopreventive effect of solid lipid nanoparticle (SLN) encapsulated drugs aspirin (ASP), curcumin (CUR) and free sulforaphane (SFN) for the chemoprevention of pancreatic cancer. Experiments were carried out (1) to evaluate the feasibility of encapsulation of these chemopreventive agents within solid lipid systems and (2) to measure the synergistic effects of a combination of ASP with CUR in SLNs mixed with free SFN against cell proliferation and apoptosis in pancreatic cancer cells, MIA PaCa-2 and Panc-1. The SLNs were prepared using a modified solvent evaporation technique and were characterized for particle sizing, encapsulation efficiency and drug release. ASP and CUR SLNs were formulated within the particle size range of 150–250 nm and were found to have an encapsulation efficiency of 85 and 69%, respectively. Sustained release of drugs over a 96 h period from SLNs was observed. The SLNs were stable over a 3-month storage period at room temperature. Cell viability studies demonstrated that combinations of low doses of ASP SLN (25 μM), CUR SLN (2.5 μM) and free SFN (5 μM) significantly reduced cell viability by 43.6 and 48.49% in MIAPaca-2 and Panc-1 cell lines, respectively. Furthermore, increased apoptosis of 61.3 and 60.37% was found in MIA Paca-2 and Panc-1 cell lines, respectively, in comparison to the individual doses administered. Synergistic effects were demonstrated using MTS and apoptosis assays. Thus, this study successfully demonstrated the feasibility of using a solid lipid nanoparticulate system for the first time to deliver this novel combination chemoprevention regimen, providing valuable evidence for the usability of nanotechnology-based drug regimens towards pancreatic cancer chemoprevention.