Phenylbutyrate Counteracts Shigella Mediated Downregulation of Cathelicidin in Rabbit Lung and Intestinal Epithelia: A Potential Therapeutic Strategy

BACKGROUND: Cathelicidins and defensins are endogenous antimicrobial peptides (AMPs) that are downregulated in the mucosal epithelia of the large intestine in shigellosis. Oral treatment of Shigella infected rabbits with sodium butyrate (NaB) reduces clinical severity and counteracts the downregulation of cathelicidin (CAP-18) in the large intestinal epithelia. AIMS: To develop novel regimen for treating infectious diseases by inducing innate immunity, we selected sodium 4-phenylbutyrate (PB), a registered drug for a metabolic disorder as a potential therapeutic candidate in a rabbit model of shigellosis. Since acute respiratory infections often cause secondary complications during shigellosis, the systemic effect of PB and NaB on CAP-18 expression in respiratory epithelia was also evaluated. METHODS: The readouts were clinical outcomes, CAP-18 expression in mucosa of colon, rectum, lung and trachea (immunohistochemistry and real-time PCR) and release of the CAP-18 peptide/protein in stool (Western blot). PRINCIPAL FINDINGS: Significant downregulation of CAP-18 expression in the epithelia of rectum and colon, the site of Shigella infection was confirmed. Interestingly, reduced expression of CAP-18 was also noticed in the epithelia of lung and trachea, indicating a systemic effect of the infection. This suggests a causative link to acute respiratory infections during shigellosis. Oral treatment with PB resulted in reduced clinical illness and upregulation of CAP-18 in the epithelium of rectum. Both PB and NaB counteracted the downregulation of CAP-18 in lung epithelium. The drug effect is suggested to be systemic as intravenous administration of NaB could also upregulate CAP-18 in the epithelia of lung, rectum and colon. CONCLUSION: Our results suggest that PB has treatment potential in human shigellosis. Enhancement of CAP-18 in the mucosal epithelia of the respiratory tract by PB or NaB is a novel discovery. This could mediate protection from secondary respiratory infections that frequently are the lethal causes in dysentery

Cell death induction in breast cancer cells with nanoparticle-facilitated delivery of classical anti-cancer drugs and siRNAs targeting growth factor receptor and multi-drug transporter genes

Cancer is the foremost cause of deaths worldwide with breast cancer being second among them [1]. Chemotherapy is the most preferred treatment tactic to treat breast cancer that is associated with copious adverse effects [2, 3] mainly caused by nonspecific targets of cancer drugs affecting highly dividing healthy cells of the body. In addition, development of resistance by cancer cells to these chemotherapeutic drugs is one of the most difficult obstacles to the clinical success of the therapy [4-6]. The classical chemical drugs most frequently used nowadays enter the cells either via the direct diffusion or the facilitated passive diffusion which is recognized by the cellular pump system [7-12]. The transporter molecules efflux drugs out of the cells decreasing drug accumulation inside the cells and causing them to acquire resistance to these drugs. In addition, cancer cells may accomplish resistance by changing the expression pattern of importer molecules that help drugs to get into the cells [13]. Furthermore, many growth factor receptors (GFRs) typically human epidermal growth factor receptors (EGFR1 and ERBB2) and insulin-like growth factor receptor (IGFR1) are overexpressed on breast cancer cells and thus influence their growth and proliferation [14] leading to tumor progression and conferring more resistance to drugs [15-18]. Designing smart carrier molecules to carry the widely used classical anticancer drugs inside the cells might help circumvent the recognition by the transporter molecules and thus enable more drugs accumulation into cells to exert more therapeutic efficacy. In addition, silencing of the transporter or GFR genes with small interfering RNAs (siRNAs) following their intracellular delivery along with drugs using an appropriate carrier molecule could be a novel approach to combat against cancer and acquired resistance more effectively. Targeted delivery of multiple siRNAs and drugs to cells could be facilitated with recently developed pH sensitive inorganic carbonate apatite nanoparticles [19-23]. These original and modified nanoparticles have been used for this study to carry the classical anti-cancer drugs (doxorubicin; Dox, methotrexate; Mtx, cyclophosphamide; Cyp and furouracil; FU) and siRNAs against GFR genes (EGFR1, ERBB2 and IGFR1) and ABC transporter genes (ABCB1, ABCG2 and ABCC1) to induce cellular cytotoxicity in human (MCF-7, MDA-MB-231) and mouse (4T1) breast cancer cell lines as well as in 4T1-induced mouse tumors. Nanoparticle complexed drug induced more cytotoxicity and tumour reduction by more cellular accumulation of drugs inside cells and co-delivery of drug and siRNAs against transporter and GFR genes via these nanoparticles induce additional cytotoxicity tumour reduction in mice

Cell death induction in breast cancer cells with nanoparticle-facilitated delivery of classical anti-cancer drugs and siRNAs targeting growth factor receptor and multi-drug transporter genes

Cancer is the foremost cause of deaths worldwide with breast cancer being second among them [1]. Chemotherapy is the most preferred treatment tactic to treat breast cancer that is associated with copious adverse effects [2, 3] mainly caused by nonspecific targets of cancer drugs affecting highly dividing healthy cells of the body. In addition, development of resistance by cancer cells to these chemotherapeutic drugs is one of the most difficult obstacles to the clinical success of the therapy [4-6]. The classical chemical drugs most frequently used nowadays enter the cells either via the direct diffusion or the facilitated passive diffusion which is recognized by the cellular pump system [7-12]. The transporter molecules efflux drugs out of the cells decreasing drug accumulation inside the cells and causing them to acquire resistance to these drugs. In addition, cancer cells may accomplish resistance by changing the expression pattern of importer molecules that help drugs to get into the cells [13]. Furthermore, many growth factor receptors (GFRs) typically human epidermal growth factor receptors (EGFR1 and ERBB2) and insulin-like growth factor receptor (IGFR1) are overexpressed on breast cancer cells and thus influence their growth and proliferation [14] leading to tumor progression and conferring more resistance to drugs [15-18]. Designing smart carrier molecules to carry the widely used classical anticancer drugs inside the cells might help circumvent the recognition by the transporter molecules and thus enable more drugs accumulation into cells to exert more therapeutic efficacy. In addition, silencing of the transporter or GFR genes with small interfering RNAs (siRNAs) following their intracellular delivery along with drugs using an appropriate carrier molecule could be a novel approach to combat against cancer and acquired resistance more effectively. Targeted delivery of multiple siRNAs and drugs to cells could be facilitated with recently developed pH sensitive inorganic carbonate apatite nanoparticles [19-23]. These original and modified nanoparticles have been used for this study to carry the classical anti-cancer drugs (doxorubicin; Dox, methotrexate; Mtx, cyclophosphamide; Cyp and furouracil; FU) and siRNAs against GFR genes (EGFR1, ERBB2 and IGFR1) and ABC transporter genes (ABCB1, ABCG2 and ABCC1) to induce cellular cytotoxicity in human (MCF-7, MDA-MB-231) and mouse (4T1) breast cancer cell lines as well as in 4T1-induced mouse tumors. Nanoparticle complexed drug induced more cytotoxicity and tumour reduction by more cellular accumulation of drugs inside cells and co-delivery of drug and siRNAs against transporter and GFR genes via these nanoparticles induce additional cytotoxicity tumour reduction in mice

Growth factor receptors: promising drug targets in cancer

Genetic, epigenetic and somatic changes deregulate the expression of growth factor receptors (GFRs), leading to cancer initiation and progression. Tumor cell growth and survival are orchestrated by clonal expansion and evasion of apoptotic signals in cancer cells. The growth of cells is further supported by angiogenesis and metastasis to distant organs. High expression of GFRs also contributes to the development of resistance. Therefore, therapeutics to target GFRs is a potentially attractive molecular approach to treat cancer more effectively. In this review, we have discussed the contribution of GFRs to cancer development and addressed molecular approaches undertaken to inhibit GFR-mediated pathways. A wide number of monoclonal antibodies (mAbs) and protein kinase inhibitors targeting these GFR-mediated functions are in clinical trials to treat human malignancies. However, most drugs that target GFRs lead to the development of drug resistance and generate adverse effects. Nucleic acid-based therapeutics, e.g. short interfering RNA (siRNA) could be harnessed to selectively silence GFR genes in cancer cells. Different polymer, liposome-based nanocarriers, and the most recently developed pH-sensitive inorganic carbonate apatite nanoparticles have been used in cell culture and preclinical trials for cytoplasmic delivery of the siRNAs targeting different GFR genes. siRNA-based therapeutics have been shown to have significant potential to suppress GFR expression and functions and thus could be developed as molecular therapeutics. Multi-targeting of tumors at different levels by combining various approaches along with chemotherapy would be a promising therapeutic approach to fight the disease. Suitable nanocarriers capable of entrapping siRNA, mAb, GFR inhibitors and classical drugs targeting GFR have potential therapeutic applications

Carbonate apatite nanoparticles carry siRNA(S) targeting growth factor receptor genes egfr1 and erbb2 to regress mouse breast tumor

Cancer cells lose their control on cell cycle by numerous genetic and epigenetic alterations. In a tumor, these cells highly express growth factor receptors (GFRs), eliciting growth, and cell division. Among the GFRs, epidermal growth factor receptor-1 (EGFR1) (Her1/ERBB1) and epidermal growth factor receptor-2 (EGFR2) (Her2/ERBB2) from epidermal growth factor (EGF) family and insulin-like growth factor-1 receptor (IGF1R) are highly expressed on breast cancer cells, thus contributing to the aggressive growth and invasiveness, have been focused in this study. Moreover, overexpression of these receptors is related to suppression of cell death and conferring resistance against the classical drugs used to treat cancer nowadays. Therefore, silencing of these GFRs-encoding genes by using selective small interfering RNAs (siRNAs) could be a powerful approach to treat breast cancer. The inorganic pH sensitive carbonate apatite nanoparticles (NPs) were used as a nano-carrier to deliver siRNA(s) against single or multiple GFR genes in breast cancer cells as well as in a mouse model of breast carcinoma. Silencing of egfr1 and erbb2 simultaneously led to a reduction in cell viability with an increase in cell death signal in the cancer cells and regression of tumor growth in vivo

siRNAs targeting growth factor receptor and anti-apoptotic genes synergistically kill breast cancer cells through inhibition of MAPK and PI-3 kinase pathways

Breast cancer, the second leading cause of female deaths worldwide, is usually treated with cytotoxic drugs, accompanied by adverse side-effects, development of chemoresistance and relapse of disease condition. Survival and proliferation of the cancer cells are greatly empowered by over-expression or over-activation of growth factor receptors and anti-apoptotic factors. Identification of these key players that cross-talk to each other, and subsequently, knockdown with their respective siRNAs in a synchronous manner could be a promising approach to precisely treat the cancer. Since siRNAs demonstrate limited cell permeability and unfavorable pharmacokinetic behaviors, pH-sensitive nanoparticles of carbonate apatite were employed to efficiently carry the siRNAs in vitro and in vivo. By delivering selective siRNAs against the mRNA transcripts of the growth factor receptors, such as ER, ERBB2 (HER2), EGFR and IGFR, and anti-apoptotic protein, such as BCL2 in human (MCF-7 and MDA-MB-231) and murine (4T1) breast cancer cell lines, we found that ESR1 along with BCL-2, or with ERBB2 and EGFR critically contributes to the growth/survival of the cancer cells by activating the MAPK and PI-3 kinase pathways. Furthermore, intravenous delivery of the selected siRNAs aiming to suppress the expression of ER/BCL2 and ER/ERBB2/EGFR groups of proteins led to a significant retardation in tumor growth in a 4T1-induced syngeneic mouse model

Carbonate apatite nanoparticles carry siRNA(s) targeting growth factor receptor genes <i>egfr1</i> and <i>erbb2</i> to regress mouse breast tumor

<p>Cancer cells lose their control on cell cycle by numerous genetic and epigenetic alterations. In a tumor, these cells highly express growth factor receptors (GFRs), eliciting growth, and cell division. Among the GFRs, epidermal growth factor receptor-1 (EGFR1) (Her1/ERBB1) and epidermal growth factor receptor-2 (EGFR2) (Her2/ERBB2) from epidermal growth factor (EGF) family and insulin-like growth factor-1 receptor (IGF1R) are highly expressed on breast cancer cells, thus contributing to the aggressive growth and invasiveness, have been focused in this study. Moreover, overexpression of these receptors is related to suppression of cell death and conferring resistance against the classical drugs used to treat cancer nowadays. Therefore, silencing of these GFRs-encoding genes by using selective small interfering RNAs (siRNAs) could be a powerful approach to treat breast cancer. The inorganic pH sensitive carbonate apatite nanoparticles (NPs) were used as a nano-carrier to deliver siRNA(s) against single or multiple <i>GFR</i> genes in breast cancer cells as well as in a mouse model of breast carcinoma. Silencing of <i>egfr1</i> and <i>erbb2</i> simultaneously led to a reduction in cell viability with an increase in cell death signal in the cancer cells and regression of tumor growth <i>in vivo</i>.</p

An image-based Pathogen Box screen identifies new compounds with anti-Giardia activity and highlights the importance of assay choice in phenotypic drug discovery.

Giardia duodenalis, the most prevalent human intestinal parasite causes the disease, giardiasis. On an annual basis G. duodenalis infects ~1 billion people, of which ~280 million develop symptomatic disease. Giardiasis can be severe and chronic, causing malnutrition, stunted growth and poor cognitive development in children. Current treatment options rely on drugs with declining efficacy and side-effects. To improve the health and well-being of millions of people world-wide, new anti-Giardia drugs with different modes of action to currently used drugs are required. The Medicines for Malaria Ventures Pathogen Box, a collection of bio-active compounds specifically chosen to stimulate infectious disease drug discovery, represents an opportunity for the discovery of new anti-Giardia agents. While the anti-Giardia activity of Pathogen Box compounds has been reported, this work failed to identify known anti-Giardia controls within the compound set. It also reported the activity of compounds previously screened and shown to be inactive by others, suggesting data may be inaccurate. Given these concerns the anti-Giardia activity of Pathogen Box compounds was re-assessed in the current study. Data from this work identified thirteen compounds with anti-Giardia IC50 values ≤2&nbsp;μM. Five of these compounds were reference compounds (marketed drugs with known anti-microbial activity), or analogues of compounds with previously described anti-Giardia activity. However, eight, including MMV676358 and MMV028694, which demonstrated potent sub-μM IC50s against assemblage A, B and metronidazole resistant parasites (0.3&nbsp;μM and 0.9&nbsp;μM respectively), may represent new leads for future drug development. Interestingly, only four of these compounds were identified in the previously reported Pathogen Box screen highlighting the importance of assay selection and design when assessing compounds for activity against infectious agents