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Tomato lycopene and lung cancer prevention: from experimental to human studies.

Palozza P, Simone RE, Catalano A, Mele MC - Cancers (Basel) (2011)

Bottom Line: Experimental studies demonstrated that lycopene may inhibit the growth of several cultured lung cancer cells and prevent lung tumorigenesis in animal models through various mechanisms, including a modulation of redox status, cell cycle arrest and/or apoptosis induction, a regulation of growth factor signaling, changes in cell growth-related enzymes, an enhancement of gap junction communication and a prevention of smoke-induced inflammation.In addition, lycopene also inhibited cell invasion, angiogenesis, and metastasis.Despite these promising reports, it is difficult at the moment to directly relate available experimental data to human pathophysiology.

View Article: PubMed Central - PubMed

Affiliation: Institute of General Pathology, School of Medicine, Catholic University, L. Go F. Vito, Rome 1 00168, Italy. p.palozza@rm.unicatt.it.

ABSTRACT
Increasing evidence suggests that tomato lycopene may be preventive against the formation and the development of lung cancer. Experimental studies demonstrated that lycopene may inhibit the growth of several cultured lung cancer cells and prevent lung tumorigenesis in animal models through various mechanisms, including a modulation of redox status, cell cycle arrest and/or apoptosis induction, a regulation of growth factor signaling, changes in cell growth-related enzymes, an enhancement of gap junction communication and a prevention of smoke-induced inflammation. In addition, lycopene also inhibited cell invasion, angiogenesis, and metastasis. Several lycopene metabolites have been identified, raising the question as to whether the preventive effects of lycopene on cancer risk is, at least in part, due to its metabolites. Despite these promising reports, it is difficult at the moment to directly relate available experimental data to human pathophysiology. More well controlled clinical intervention trials are needed to further clarify the exact role of lycopene in the prevention of lung cancer cell growth. Such studies should take into consideration subject selection, specific markers of analysis, the levels of carotenoids being tested, metabolism and isomerization of lycopene, interaction with other bioactive food components. This article reviews data on the cancer preventive activities of lycopene, possible mechanisms involved, and the relationship between lycopene consumption and human cancer risk.

No MeSH data available.


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Chemical structure of lycopene.
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f1-cancers-03-02333: Chemical structure of lycopene.

Mentions: Among the different carotenoids, one of the ongoing research candidates for the prevention of lung cancer risk is lycopene. Lycopene, one of more than 600 carotenoids synthesized by plants and photosynthetic microorganism [10], is a tetraterpene hydrocarbon containing 40 carbon atoms and 56 hydrogen atoms. Lycopene is the most abundant carotenoid in tomatoes (Lycopersicon esculentum L.) with concentrations ranging from 0.9–4.2 mg/100 g depending upon the variety [11]. Tomato sauce and ketchup are concentrated sources of lycopene compared to unprocessed tomatoes [12]. Other edible sources of lycopene include rosehips [13], watermelon, papaya, pink grapefruit, and guava [14]. Belonging to the hydrocarbon carotene class of carotenoids, lycopene is acyclic and contains 11 conjugated and two non-conjugated double bonds (Figure 1). Because it is acyclic and lacks a bionone ring, lycopene has no pro-vitamin A activity. Although dietary lycopene is predominantly all-trans, more than 50% of the lycopene present in human serum and tissues is in cis-forms [15]. Lycopene absorption from dietary sources is influenced by several factors, such as the break up of the food matrix containing lycopene, cooking temperatures and the presence of lipids and other lipid soluble compounds including other carotenoids [16]. Absorption of lycopene is similar to that of other lipid soluble compounds and is absorbed across the gastrointestinal tract via a chylomicron mediated mechanism. Incorporated into chylomicrons, lycopene and other carotenoids are transported from the intestinal mucosa to the general circulation via the lymphatic system. In the blood, carotenoids are transported by lipoproteins. In particular, LDL is the primary carrier of lycopene. In general, 10–30% of the dietary lycopene is absorbed by humans. It is absorbed equally efficiently from different sources of lycopene including tomato sauce, tomato juice and tomato oleoresin capsules [17]. Liver, seminal vesicles and prostate tissue are the primary sites of lycopene accumulation in vivo [18]. Furthermore, Liu et al. [19] found that lycopene can be selectively localized to the nuclear membrane and nuclear matrix, suggesting a possible role for a lycopene receptor or transporter. Lycopene in the tissues undergoes oxidation and metabolism. Several oxidized form of lycopene and polar metabolites have been isolated and identified [20]. Apo-6′and apo-8′-lycopenals were reported to be present in raw tomatoes [21]. Some lycopene metabolites, including 5,6-dihydroxy-5,6-dihydro-lycopene [22], and apo-6′-, apo-8′-, apo-10′-, apo-12′- and apo-14′-lycopenals have been also detected in human plasma.


Tomato lycopene and lung cancer prevention: from experimental to human studies.

Palozza P, Simone RE, Catalano A, Mele MC - Cancers (Basel) (2011)

Chemical structure of lycopene.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3757421&req=5

f1-cancers-03-02333: Chemical structure of lycopene.
Mentions: Among the different carotenoids, one of the ongoing research candidates for the prevention of lung cancer risk is lycopene. Lycopene, one of more than 600 carotenoids synthesized by plants and photosynthetic microorganism [10], is a tetraterpene hydrocarbon containing 40 carbon atoms and 56 hydrogen atoms. Lycopene is the most abundant carotenoid in tomatoes (Lycopersicon esculentum L.) with concentrations ranging from 0.9–4.2 mg/100 g depending upon the variety [11]. Tomato sauce and ketchup are concentrated sources of lycopene compared to unprocessed tomatoes [12]. Other edible sources of lycopene include rosehips [13], watermelon, papaya, pink grapefruit, and guava [14]. Belonging to the hydrocarbon carotene class of carotenoids, lycopene is acyclic and contains 11 conjugated and two non-conjugated double bonds (Figure 1). Because it is acyclic and lacks a bionone ring, lycopene has no pro-vitamin A activity. Although dietary lycopene is predominantly all-trans, more than 50% of the lycopene present in human serum and tissues is in cis-forms [15]. Lycopene absorption from dietary sources is influenced by several factors, such as the break up of the food matrix containing lycopene, cooking temperatures and the presence of lipids and other lipid soluble compounds including other carotenoids [16]. Absorption of lycopene is similar to that of other lipid soluble compounds and is absorbed across the gastrointestinal tract via a chylomicron mediated mechanism. Incorporated into chylomicrons, lycopene and other carotenoids are transported from the intestinal mucosa to the general circulation via the lymphatic system. In the blood, carotenoids are transported by lipoproteins. In particular, LDL is the primary carrier of lycopene. In general, 10–30% of the dietary lycopene is absorbed by humans. It is absorbed equally efficiently from different sources of lycopene including tomato sauce, tomato juice and tomato oleoresin capsules [17]. Liver, seminal vesicles and prostate tissue are the primary sites of lycopene accumulation in vivo [18]. Furthermore, Liu et al. [19] found that lycopene can be selectively localized to the nuclear membrane and nuclear matrix, suggesting a possible role for a lycopene receptor or transporter. Lycopene in the tissues undergoes oxidation and metabolism. Several oxidized form of lycopene and polar metabolites have been isolated and identified [20]. Apo-6′and apo-8′-lycopenals were reported to be present in raw tomatoes [21]. Some lycopene metabolites, including 5,6-dihydroxy-5,6-dihydro-lycopene [22], and apo-6′-, apo-8′-, apo-10′-, apo-12′- and apo-14′-lycopenals have been also detected in human plasma.

Bottom Line: Experimental studies demonstrated that lycopene may inhibit the growth of several cultured lung cancer cells and prevent lung tumorigenesis in animal models through various mechanisms, including a modulation of redox status, cell cycle arrest and/or apoptosis induction, a regulation of growth factor signaling, changes in cell growth-related enzymes, an enhancement of gap junction communication and a prevention of smoke-induced inflammation.In addition, lycopene also inhibited cell invasion, angiogenesis, and metastasis.Despite these promising reports, it is difficult at the moment to directly relate available experimental data to human pathophysiology.

View Article: PubMed Central - PubMed

Affiliation: Institute of General Pathology, School of Medicine, Catholic University, L. Go F. Vito, Rome 1 00168, Italy. p.palozza@rm.unicatt.it.

ABSTRACT
Increasing evidence suggests that tomato lycopene may be preventive against the formation and the development of lung cancer. Experimental studies demonstrated that lycopene may inhibit the growth of several cultured lung cancer cells and prevent lung tumorigenesis in animal models through various mechanisms, including a modulation of redox status, cell cycle arrest and/or apoptosis induction, a regulation of growth factor signaling, changes in cell growth-related enzymes, an enhancement of gap junction communication and a prevention of smoke-induced inflammation. In addition, lycopene also inhibited cell invasion, angiogenesis, and metastasis. Several lycopene metabolites have been identified, raising the question as to whether the preventive effects of lycopene on cancer risk is, at least in part, due to its metabolites. Despite these promising reports, it is difficult at the moment to directly relate available experimental data to human pathophysiology. More well controlled clinical intervention trials are needed to further clarify the exact role of lycopene in the prevention of lung cancer cell growth. Such studies should take into consideration subject selection, specific markers of analysis, the levels of carotenoids being tested, metabolism and isomerization of lycopene, interaction with other bioactive food components. This article reviews data on the cancer preventive activities of lycopene, possible mechanisms involved, and the relationship between lycopene consumption and human cancer risk.

No MeSH data available.


Related in: MedlinePlus