Background/Objectives: In the Middle East, people consume camel milk regularly as it is believed to improve immunity against diseases and decrease the risk for cancer. Recently, it was noted that most of the beneficial effects of milk come from their nanoparticles, especially exosomes. Herein, we evaluated the anticancer potential of camel milk and its exosomes on MCF7 breast cancer cells (in vitro and in vivo) and investigated the possible underlying molecular mechanism of action. Methods/Results: Administration of camel milk (orally) and its exosomes (orally and by local injection) decreased breast tumor progression as evident by ( a) higher apoptosis (indicated by higher DNA fragmentation, caspase-3 activity, Bax gene expression, and lower Bcl2 gene expression), ( b) remarkable inhibition of oxidative stress (decrease in MDA levels and iNOS gene expression); ( c) induction of antioxidant status (increased activities of SOD, CAT, and GPX), ( d) notable reduction in expression of inflammation-( IL1b, NFκB), angiogenesis-( VEGF) and metastasis-( MMP9, ICAM1) related genes; and ( e) higher immune response (high number of CD⁺4, CD⁺8, NK1.1 T cells in spleen). Conclusions: Overall, administration of camel milk–derived exosomes showed better anticancer effect, but less immune response, than treatment by camel milk. Moreover, local injection of exosomes led to better improvement than oral administration. These findings suggest that camel milk and its exosomes have anticancer effect possibly through induction of apoptosis and inhibition of oxidative stress, inflammation, angiogenesis and metastasis in the tumor microenvironment. Thus, camel milk and its exosomes could be used as an anticancer agent for cancer treatment.

Cross talk, mediated by exosomes, between normal stem cells and cancer stem cells (CSCs) in the tumor microenvironment has been given less attention so far. In addition, no publications are available in the literature that address the in vivo impact of exosomes derived from CSCs and mesenchymal stem cells (MSCs) on progression of long-term hepatocellular carcinoma (HCC). Herein, we hypothesized that transfer of exosomes among the cells in the HCC microenvironment could either induce or inhibit tumor growth and metastasis depending on their source. To check this hypothesis, we investigated the effect of exosomes coming from two different stem cell populations, hepatic CSCs and bone marrow (BM) MSCs, on progression of long-term DEN-induced HCC in rats and the involved underlying mechanisms. CSCs-exosomes induced a significant increase in liver relative weight and serum levels of cancer markers (AFP and GGT) and liver enzymes (ALT, AST, and ALP), intensive immunostaining for the HCC marker GST-P, and an increased number and area of tumor nodules as compared to HCC rats injected by PBS. CSCs-exosomes also decreased apoptosis (marked by downregulation of Bax and p53 and upregulation of Bcl2, and increased immunostaining of PCNA), increased angiogenetic activity (revealed by upregulation of VEGF), enhanced metastasis and invasiveness (indicated by upregulation of P13K and ERK proteins and their downstream target MMP9 and downregulation of TIMP1), and induced epithelial mesenchymal transition (marked by increased serum and hepatic level of TGFβ1 mRNA and protein). Notably, CSCs-exosomes also elevated HCC exosomal microRNA (miR) 21, exosomal long noncoding (lnc) RNA Tuc339, lncHEIH, and the HCC lncHOTAIR and decreased liver miR122 and HCC miRs (miR148a, miR16, and miR125b). All these cellular, functional, and molecular changes were reversed following injection of BM-MSCs-exosomes. However, both CSCs- and MSCs-exosomes failed to change the elevated oxidative stress or the inhibited antioxidant activities induced by HCC. Collectively, our results revealed a tumor stimulatory effect (induction of tumor growth, progression, and metastasis) for exosomes derived from CSCs and an inhibitory effect for exosomes derived from MSCs. These results provide valuable insight on the effect of CSCs- and MSCs-exosomes on HCC growth and progression in vivo, which may be helpful to understand the mechanism of HCC development.

Camel milk proteins exhibit many beneficial properties including immuno-modulatory and anti-oxidant effects. Recent studies demonstrated that most of these properties are ascribed to the presence of extracellular nanovesicles known as exosomes. Therefore, the current study aimed to investigate the effect of the immuno-modulatory and anti-oxidant properties of camel milk exosomes on the immuno-toxicity and oxidative stress induced by cyclophosphamide (CTX) in albino rats. Exosomes were isolated from camel milk and exosomal kappa casein and lactoferrin mRNAs were detected and then sequenced. CTX was used to induce immunosuppression in rats, which were further treated with camel milk and its exosomes. The alterations in biochemical parameters, antioxidant status, cytokine profile, spleen histopathology and flow cytometric analysis were detected. Treatment with CTX resulted in a significant decrease in total protein, albumin, globulin, catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) levels associated with a significant increase in the levels of malondialdehyde (MDA) when compared with the control group. Moreover, CTX depleted lymphocytes in the spleen tissue, significantly reduced the expression of interferon gamma (IFN-γ) in the spleen cells and decreased the CD4⁺ and CD8⁺ cell percentages in the blood and spleen, while it induced a significant increase in the expression of interleukin (IL)-6 and tumor necrosis factor (TNF)-α. Co-administration of camel milk exosomes was able to normalize the antioxidant status and most of the biochemical and immunological parameters. This study clarifies that camel milk and its exosomes successfully ameliorate immunosuppression and oxidative stress induced by CTX in rats.

This study was conducted to investigate the mechanism of lead (Pb)-induced testicular toxicity. We examined the impact of Pb toxicity on 17β-oestradiol (E2), oestrogen receptors (ERs) and aromatase P450 which are key factors in spermatogenesis. Treatment of rats with Pb acetate (PbAc, 50 mg/L in drinking water) significantly reduced sperm count, motility, viability and increased sperm abnormalities along with degenerative changes in seminiferous tubules and Leydig cells. Additionally, administration of PbAc resulted in a significant reduction in serum testosterone, serum and testicular E2 as well as increased level of testicular testosterone. Pb also induced testicular oxidative stress as evidenced by a significant decrease in the activities of superoxide dismutase, glutathione peroxidase and catalase antioxidant enzymes, and increased malondialdehyde level in the testis. At the molecular level, Pb treatment downregulated the mRNA expression of P450 arom (Cyp19) and ERα. In conclusion, Pb induces testicular oxidative damage and disrupts spermatogenesis, at least in part, via downregulation of Cyp19 and ERα expression, which further decrease E2 level. These data, therefore, provide insight into the mechanism of lead-induced testicular toxicity.