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Pronounced cancer resistance in a subterranean rodent, the blind mole-rat, Spalax: in vivo and in vitro evidence.

Manov I, Hirsh M, Iancu TC, Malik A, Sotnichenko N, Band M, Avivi A, Shams I - BMC Biol. (2013)

Bottom Line: This was accompanied by decreased cancer cell viability, reduced colony formation in soft agar, disturbed cell cycle progression, chromatin condensation and mitochondrial fragmentation.Spalax fibroblast conditioned media had no effect on proliferation of noncancerous cells.Obviously, along with adaptation to hypoxia, Spalax has evolved efficient anti-cancer mechanisms yet to be elucidated.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Evolution, University of Haifa, Haifa 31095, Israel.

ABSTRACT

Background: Subterranean blind mole rats (Spalax) are hypoxia tolerant (down to 3% O2), long lived (>20 years) rodents showing no clear signs of aging or aging related disorders. In 50 years of Spalax research, spontaneous tumors have never been recorded among thousands of individuals. Here we addressed the questions of (1) whether Spalax is resistant to chemically-induced tumorigenesis, and (2) whether normal fibroblasts isolated from Spalax possess tumor-suppressive activity.

Results: Treating animals with 3-Methylcholantrene (3MCA) and 7,12-Dimethylbenz(a) anthracene/12-O-tetradecanoylphorbol-13-acetate (DMBA/TPA), two potent carcinogens, confirmed Spalax high resistance to chemically induced cancers. While all mice and rats developed the expected tumors following treatment with both carcinogens, among Spalax no tumors were observed after DMBA/TPA treatment, while 3MCA induced benign fibroblastic proliferation in 2 Spalax individuals out of12, and only a single animal from the advanced age group developed malignancy 18 months post-treatment. The remaining animals are still healthy 30 months post-treatment. In vitro experiments showed an extraordinary ability of normal Spalax cultured fibroblasts to restrict malignant behavior in a broad spectrum of human-derived and in newly isolated Spalax 3MCA-induced cancer cell lines. Growth of cancer cells was inhibited by either direct interaction with Spalax fibroblasts or with soluble factors released into culture media and soft agar. This was accompanied by decreased cancer cell viability, reduced colony formation in soft agar, disturbed cell cycle progression, chromatin condensation and mitochondrial fragmentation. Cells from another cancer resistant subterranean mammal, the naked mole rat, were also tested for direct effect on cancer cells and, similar to Spalax, demonstrated anti-cancer activity. No effect on cancer cells was observed using fibroblasts from mouse, rat or Acomys. Spalax fibroblast conditioned media had no effect on proliferation of noncancerous cells.

Conclusions: This report provides pioneering evidence that Spalax is not only resistant to spontaneous cancer but also to experimentally induced cancer, and shows the unique ability of Spalax normal fibroblasts to inhibit growth and kill cancer cells, but not normal cells, either through direct fibroblast-cancer cell interaction or via soluble factors. Obviously, along with adaptation to hypoxia, Spalax has evolved efficient anti-cancer mechanisms yet to be elucidated. Exploring the molecular mechanisms allowing Spalax to survive in extreme environments and to escape cancer as well as to kill homologous and heterologous cancer cells may hold the key for understanding the molecular nature of host resistance to cancer and identify new anti-cancer strategies for treating humans.

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Comparison of the effects of Spalax, Acomys, Heterocephalus and rat skin fibroblasts on growth of Hep3B cells. Hep3B tumor cells were cultured either alone or in presence of Spalax, Acomys, Heterocephalus or rat fibroblasts in the ratio of 1:10 (5 × 104 fibroblasts and 5 × 103 cancer cells in six-well plates) in RPMI/DMEM-F12 media (1:1) containing 10% FBS. After seven days incubation cells were photographed. Representative images for each sample are shown (×200). White arrows point to the foci of damaged cancer cells. TC, tumor cells.
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Figure 6: Comparison of the effects of Spalax, Acomys, Heterocephalus and rat skin fibroblasts on growth of Hep3B cells. Hep3B tumor cells were cultured either alone or in presence of Spalax, Acomys, Heterocephalus or rat fibroblasts in the ratio of 1:10 (5 × 104 fibroblasts and 5 × 103 cancer cells in six-well plates) in RPMI/DMEM-F12 media (1:1) containing 10% FBS. After seven days incubation cells were photographed. Representative images for each sample are shown (×200). White arrows point to the foci of damaged cancer cells. TC, tumor cells.

Mentions: Since we compare a wild mammal with laboratory animals that are sensitive to cancer, we conducted co-culture experiments using Hep3B cancer cells with skin fibroblasts isolated from two different wild, natural rodents: Acomys, a short-lived, wild, above-ground rodent; and naked mole rat (Heterocephalus glaber), a long-lived cancer-resistant wild subterranean rodent [22]. As shown (Figure 6), no growth inhibitory effect was found when Acomys fibroblasts were co-cultured with Hep3B cells. On the contrary, Acomys fibroblasts promoted cancer cell invasion similar to the effect of rat fibroblasts. Heterocephalus cells, similar to Spalax, evidently destroyed cancer cell growth (Figure 6).


Pronounced cancer resistance in a subterranean rodent, the blind mole-rat, Spalax: in vivo and in vitro evidence.

Manov I, Hirsh M, Iancu TC, Malik A, Sotnichenko N, Band M, Avivi A, Shams I - BMC Biol. (2013)

Comparison of the effects of Spalax, Acomys, Heterocephalus and rat skin fibroblasts on growth of Hep3B cells. Hep3B tumor cells were cultured either alone or in presence of Spalax, Acomys, Heterocephalus or rat fibroblasts in the ratio of 1:10 (5 × 104 fibroblasts and 5 × 103 cancer cells in six-well plates) in RPMI/DMEM-F12 media (1:1) containing 10% FBS. After seven days incubation cells were photographed. Representative images for each sample are shown (×200). White arrows point to the foci of damaged cancer cells. TC, tumor cells.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3750378&req=5

Figure 6: Comparison of the effects of Spalax, Acomys, Heterocephalus and rat skin fibroblasts on growth of Hep3B cells. Hep3B tumor cells were cultured either alone or in presence of Spalax, Acomys, Heterocephalus or rat fibroblasts in the ratio of 1:10 (5 × 104 fibroblasts and 5 × 103 cancer cells in six-well plates) in RPMI/DMEM-F12 media (1:1) containing 10% FBS. After seven days incubation cells were photographed. Representative images for each sample are shown (×200). White arrows point to the foci of damaged cancer cells. TC, tumor cells.
Mentions: Since we compare a wild mammal with laboratory animals that are sensitive to cancer, we conducted co-culture experiments using Hep3B cancer cells with skin fibroblasts isolated from two different wild, natural rodents: Acomys, a short-lived, wild, above-ground rodent; and naked mole rat (Heterocephalus glaber), a long-lived cancer-resistant wild subterranean rodent [22]. As shown (Figure 6), no growth inhibitory effect was found when Acomys fibroblasts were co-cultured with Hep3B cells. On the contrary, Acomys fibroblasts promoted cancer cell invasion similar to the effect of rat fibroblasts. Heterocephalus cells, similar to Spalax, evidently destroyed cancer cell growth (Figure 6).

Bottom Line: This was accompanied by decreased cancer cell viability, reduced colony formation in soft agar, disturbed cell cycle progression, chromatin condensation and mitochondrial fragmentation.Spalax fibroblast conditioned media had no effect on proliferation of noncancerous cells.Obviously, along with adaptation to hypoxia, Spalax has evolved efficient anti-cancer mechanisms yet to be elucidated.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Evolution, University of Haifa, Haifa 31095, Israel.

ABSTRACT

Background: Subterranean blind mole rats (Spalax) are hypoxia tolerant (down to 3% O2), long lived (>20 years) rodents showing no clear signs of aging or aging related disorders. In 50 years of Spalax research, spontaneous tumors have never been recorded among thousands of individuals. Here we addressed the questions of (1) whether Spalax is resistant to chemically-induced tumorigenesis, and (2) whether normal fibroblasts isolated from Spalax possess tumor-suppressive activity.

Results: Treating animals with 3-Methylcholantrene (3MCA) and 7,12-Dimethylbenz(a) anthracene/12-O-tetradecanoylphorbol-13-acetate (DMBA/TPA), two potent carcinogens, confirmed Spalax high resistance to chemically induced cancers. While all mice and rats developed the expected tumors following treatment with both carcinogens, among Spalax no tumors were observed after DMBA/TPA treatment, while 3MCA induced benign fibroblastic proliferation in 2 Spalax individuals out of12, and only a single animal from the advanced age group developed malignancy 18 months post-treatment. The remaining animals are still healthy 30 months post-treatment. In vitro experiments showed an extraordinary ability of normal Spalax cultured fibroblasts to restrict malignant behavior in a broad spectrum of human-derived and in newly isolated Spalax 3MCA-induced cancer cell lines. Growth of cancer cells was inhibited by either direct interaction with Spalax fibroblasts or with soluble factors released into culture media and soft agar. This was accompanied by decreased cancer cell viability, reduced colony formation in soft agar, disturbed cell cycle progression, chromatin condensation and mitochondrial fragmentation. Cells from another cancer resistant subterranean mammal, the naked mole rat, were also tested for direct effect on cancer cells and, similar to Spalax, demonstrated anti-cancer activity. No effect on cancer cells was observed using fibroblasts from mouse, rat or Acomys. Spalax fibroblast conditioned media had no effect on proliferation of noncancerous cells.

Conclusions: This report provides pioneering evidence that Spalax is not only resistant to spontaneous cancer but also to experimentally induced cancer, and shows the unique ability of Spalax normal fibroblasts to inhibit growth and kill cancer cells, but not normal cells, either through direct fibroblast-cancer cell interaction or via soluble factors. Obviously, along with adaptation to hypoxia, Spalax has evolved efficient anti-cancer mechanisms yet to be elucidated. Exploring the molecular mechanisms allowing Spalax to survive in extreme environments and to escape cancer as well as to kill homologous and heterologous cancer cells may hold the key for understanding the molecular nature of host resistance to cancer and identify new anti-cancer strategies for treating humans.

Show MeSH
Related in: MedlinePlus