252
Prevention of Cancer
Cancer is a leading cause of death around the globe. There are several environmental and lifestyle factors which play a role in the development of cancer like tobacco,
alcohol consumption, sun exposure etc. (Anand et al. 2008; Hernández-Ledesma
et al. 2014). Dietary patterns and food consumption is also reported to be associated
with many types of cancer. On the other hand, several studies (in vitro and in vivo)
have demonstrated the potential of food compound to lower the risk of cancer (De
Kok et al. 2008).
Peptides that are able to decrease or inhibit cell proliferation are called antitumor
peptides (Blanco‐Míguez et al. 2016). These peptides are mostly reported in in vitro
studies with cell-culture models. A few clinical trials on animal models and humans
have also shown potential anticancer effects (Zhang et al. 2014). However, clear
results of anticancer peptides are still insufficient. It is suggested that the low intrinsic toxicity and high tissue-penetration and permeability make bioactive peptides a
good anticancer agent (Cicero et al. 2017). Bioactive peptides have also exhibited
their cytotoxic activity in cancer cell lines by either acting as cytotoxic agents themselves or acting as carriers of cytotoxic agents and radioisotopes that may target
cancer cells (Thundimadathil 2012). They are not genotoxic and may affect specific
molecular pathways that participate in carcinogenesis (Blanco‐Míguez et al. 2016).
Generally, the main mechanisms of action shown by bioactive peptides are antioxidant activity, induction of apoptosis, inhibition of tumor angiogenesis, inhibition of
cell migration, cytotoxicity and inhibition of cell proliferation (Schweizer 2009;
Tyagi et al. 2014). Table 1 summarizes the different types of bioactive peptides that
show anticancer effects.
Colon and mammary tumorigenesis in murine model studies have demonstrated
whey proteins to be better than other dietary proteins in terms of suppressing tumor
development (Sasaki and Kume 2007). This is due to whey protein containing high
concentrations of cysteine and glutamylcyst(e)ine dipeptides. These peptides act as
substrates for synthesis of a unique cellular antioxidant glutathione, that removes
reactive oxygen species and detoxifies carcinogens (Sasaki and Kume 2007). Intact
whey proteins have comparably tight structure and are less approachable to mutagens, while caseins are more accessible to mutagens because of their loose micellar
structure (Bosselaers et al. 1994). Moreover, in silico studies indicate that amino
acids like lysine, alanine, glycine, and serine predominate various positions in anticancer peptides obtained from whey proteins (Sah et al. 2015).
Amongst the whey proteins explored, lactoferrin remains the most extensively
studied, followed by β-lactoglobulin, α-lactalbumin, and serum albumin (Parodi
2007). A minor component of whey proteins, lactoferrin inhibits intestinal tumors
by mechanisms of apoptosis, inhibiting angiogenesis, and regulating carcinogen
metabolizing enzymes (Pepe et al. 2013). Zhang et al. (2015) reported the growth
inhibition of MCF-7 breast cancer cells by bovine lactoferrin through apoptotic
pathway. A different in vivo study on bovine lactoferrin in mouse model showed
improvement in chemotherapeutic effects of tamoxifen in basal-like breast cancer
S. Maqsood et al.
Prevention of Cancer
Cancer is a leading cause of death around the globe. There are several environmental and lifestyle factors which play a role in the development of cancer like tobacco,
alcohol consumption, sun exposure etc. (Anand et al. 2008; Hernández-Ledesma
et al. 2014). Dietary patterns and food consumption is also reported to be associated
with many types of cancer. On the other hand, several studies (in vitro and in vivo)
have demonstrated the potential of food compound to lower the risk of cancer (De
Kok et al. 2008).
Peptides that are able to decrease or inhibit cell proliferation are called antitumor
peptides (Blanco‐Míguez et al. 2016). These peptides are mostly reported in in vitro
studies with cell-culture models. A few clinical trials on animal models and humans
have also shown potential anticancer effects (Zhang et al. 2014). However, clear
results of anticancer peptides are still insufficient. It is suggested that the low intrinsic toxicity and high tissue-penetration and permeability make bioactive peptides a
good anticancer agent (Cicero et al. 2017). Bioactive peptides have also exhibited
their cytotoxic activity in cancer cell lines by either acting as cytotoxic agents themselves or acting as carriers of cytotoxic agents and radioisotopes that may target
cancer cells (Thundimadathil 2012). They are not genotoxic and may affect specific
molecular pathways that participate in carcinogenesis (Blanco‐Míguez et al. 2016).
Generally, the main mechanisms of action shown by bioactive peptides are antioxidant activity, induction of apoptosis, inhibition of tumor angiogenesis, inhibition of
cell migration, cytotoxicity and inhibition of cell proliferation (Schweizer 2009;
Tyagi et al. 2014). Table 1 summarizes the different types of bioactive peptides that
show anticancer effects.
Colon and mammary tumorigenesis in murine model studies have demonstrated
whey proteins to be better than other dietary proteins in terms of suppressing tumor
development (Sasaki and Kume 2007). This is due to whey protein containing high
concentrations of cysteine and glutamylcyst(e)ine dipeptides. These peptides act as
substrates for synthesis of a unique cellular antioxidant glutathione, that removes
reactive oxygen species and detoxifies carcinogens (Sasaki and Kume 2007). Intact
whey proteins have comparably tight structure and are less approachable to mutagens, while caseins are more accessible to mutagens because of their loose micellar
structure (Bosselaers et al. 1994). Moreover, in silico studies indicate that amino
acids like lysine, alanine, glycine, and serine predominate various positions in anticancer peptides obtained from whey proteins (Sah et al. 2015).
Amongst the whey proteins explored, lactoferrin remains the most extensively
studied, followed by β-lactoglobulin, α-lactalbumin, and serum albumin (Parodi
2007). A minor component of whey proteins, lactoferrin inhibits intestinal tumors
by mechanisms of apoptosis, inhibiting angiogenesis, and regulating carcinogen
metabolizing enzymes (Pepe et al. 2013). Zhang et al. (2015) reported the growth
inhibition of MCF-7 breast cancer cells by bovine lactoferrin through apoptotic
pathway. A different in vivo study on bovine lactoferrin in mouse model showed
improvement in chemotherapeutic effects of tamoxifen in basal-like breast cancer
S. Maqsood et al.