Limits...
MITOSTATIN, a putative tumor suppressor on chromosome 12q24.1, is downregulated in human bladder and breast cancer.

Vecchione A, Fassan M, Anesti V, Morrione A, Goldoni S, Baldassarre G, Byrne D, D'Arca D, Palazzo JP, Lloyd J, Scorrano L, Gomella LG, Iozzo RV, Baffa R - Oncogene (2008)

Bottom Line: Human MITOSTATIN was found within a 3.2-kb transcript, which encoded a approximately 62 kDa, ubiquitously expressed protein with little homology to any known protein.We found homozygous deletions and mutations of MITOSTATIN gene in approximately 5 and approximately 11% of various cancer-derived cells and solid tumors, respectively.Finally, MITOSTATIN expression was significantly reduced in primary bladder and breast tumors, and its reduction was associated with advanced tumor stages.

View Article: PubMed Central - PubMed

Affiliation: Department of Urology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA.

ABSTRACT
Allelic deletions on human chromosome 12q24 are frequently reported in a variety of malignant neoplasms, indicating the presence of a tumor suppressor gene(s) in this chromosomal region. However, no reasonable candidate has been identified so far. In this study, we report the cloning and functional characterization of a novel mitochondrial protein with tumor suppressor activity, henceforth designated MITOSTATIN. Human MITOSTATIN was found within a 3.2-kb transcript, which encoded a approximately 62 kDa, ubiquitously expressed protein with little homology to any known protein. We found homozygous deletions and mutations of MITOSTATIN gene in approximately 5 and approximately 11% of various cancer-derived cells and solid tumors, respectively. When transiently overexpressed, MITOSTATIN inhibited colony formation, tumor cell growth and was proapoptotic, all features shared by established tumor suppressor genes. We discovered a specific link between MITOSTATIN overexpression and downregulation of Hsp27. Conversely, MITOSTATIN knockdown cells showed an increase in cell growth and cell survival rates. Finally, MITOSTATIN expression was significantly reduced in primary bladder and breast tumors, and its reduction was associated with advanced tumor stages. Our findings support the hypothesis that MITOSTATIN has many hallmarks of a classical tumor suppressor in solid tumors and may play an important role in cancer development and progression.

Show MeSH

Related in: MedlinePlus

MITOSTATIN is deleted in cancer, mutated in cancer cell lines and its expression is decreased in advanced tumor stages(a) MITOSTATIN ORF was not detected by RT-PCR in three primary prostate tumors (PC), two colon adenocarcinoma (CC) and one carcinoma of the vulva (VU). In the three prostate samples we also studied the normal counterpart in which the gene was normally expressed. (b) Examples of immunohistochemical detection of MITOSTATIN in human breast and bladder. MITOSTATIN cytoplasmatic staining was observed in normal breast (upper left panel) and bladder (upper right panel) human specimens. Normal mammary glands show a very intense MITOSTATIN-staining in both cytoplasm and cellular membrane (upper left panel). Examples of MITOSTATIN positive breast (middle left panel) and bladder (middle right panel) cancers and negative breast (lower left panel) and bladder (lower right panel) tumors. (X400). (c) MITOSTATIN immunohistochemical expression is decreased in advanced stages in breast and prostate. The distribution of the immunohistochemical scores in the different tumor stages is shown. Original magnifications 10x, 20x and 40x.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2628456&req=5

Figure 8: MITOSTATIN is deleted in cancer, mutated in cancer cell lines and its expression is decreased in advanced tumor stages(a) MITOSTATIN ORF was not detected by RT-PCR in three primary prostate tumors (PC), two colon adenocarcinoma (CC) and one carcinoma of the vulva (VU). In the three prostate samples we also studied the normal counterpart in which the gene was normally expressed. (b) Examples of immunohistochemical detection of MITOSTATIN in human breast and bladder. MITOSTATIN cytoplasmatic staining was observed in normal breast (upper left panel) and bladder (upper right panel) human specimens. Normal mammary glands show a very intense MITOSTATIN-staining in both cytoplasm and cellular membrane (upper left panel). Examples of MITOSTATIN positive breast (middle left panel) and bladder (middle right panel) cancers and negative breast (lower left panel) and bladder (lower right panel) tumors. (X400). (c) MITOSTATIN immunohistochemical expression is decreased in advanced stages in breast and prostate. The distribution of the immunohistochemical scores in the different tumor stages is shown. Original magnifications 10x, 20x and 40x.

Mentions: To determine whether MITOSTATIN is mutated or lost in malignant human tumors, we performed a systematic analysis of cancer-derived cell lines and solid tumors using RT-PCR. MITOSTATIN mRNA was absent in ~6% of the cancer samples (1 vulva, 2 colon and 3 prostate cancers; 4.2% including the cancer cell lines). Also in the three prostate samples, we studied the normal counterpart in which the gene was normally expressed (Figure 8a). Four point mutations were detected (Figure S8). In the gastric carcinoma derived RF48 cell line, T345 in exon 2 was substituted in heterozygosity by a C, changing the aminoacid from a serine to a proline (S44P). In the prostate derived LNCaP cell line, C 184 in exon 9 was substituted in heterozygosity by a T, without aminoacid changes (A323A). In the pancreatic carcinoma derived SU86 cell line, G 890 in exon 6 was substituted in heterozygosity by an A, without changing the glutamic acid (E225E). In the CAPAN1 pancreatic carcinoma derived cells, C 492 in exon 3 was homozygously mutated to A, changing the aminoacid from glutamic acid to lysine (E93K). Notably, all these mutations affected aminoacid residues that are highly conserved in evolution (Figure 1c and Figure S8). In immunofluorence confocal analysis MITOSTATIN still showed a punctuate pattern of distribution and co-localized within mitochondria in LNCaP (Figure S5), CAPAN and Su86.


MITOSTATIN, a putative tumor suppressor on chromosome 12q24.1, is downregulated in human bladder and breast cancer.

Vecchione A, Fassan M, Anesti V, Morrione A, Goldoni S, Baldassarre G, Byrne D, D'Arca D, Palazzo JP, Lloyd J, Scorrano L, Gomella LG, Iozzo RV, Baffa R - Oncogene (2008)

MITOSTATIN is deleted in cancer, mutated in cancer cell lines and its expression is decreased in advanced tumor stages(a) MITOSTATIN ORF was not detected by RT-PCR in three primary prostate tumors (PC), two colon adenocarcinoma (CC) and one carcinoma of the vulva (VU). In the three prostate samples we also studied the normal counterpart in which the gene was normally expressed. (b) Examples of immunohistochemical detection of MITOSTATIN in human breast and bladder. MITOSTATIN cytoplasmatic staining was observed in normal breast (upper left panel) and bladder (upper right panel) human specimens. Normal mammary glands show a very intense MITOSTATIN-staining in both cytoplasm and cellular membrane (upper left panel). Examples of MITOSTATIN positive breast (middle left panel) and bladder (middle right panel) cancers and negative breast (lower left panel) and bladder (lower right panel) tumors. (X400). (c) MITOSTATIN immunohistochemical expression is decreased in advanced stages in breast and prostate. The distribution of the immunohistochemical scores in the different tumor stages is shown. Original magnifications 10x, 20x and 40x.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2628456&req=5

Figure 8: MITOSTATIN is deleted in cancer, mutated in cancer cell lines and its expression is decreased in advanced tumor stages(a) MITOSTATIN ORF was not detected by RT-PCR in three primary prostate tumors (PC), two colon adenocarcinoma (CC) and one carcinoma of the vulva (VU). In the three prostate samples we also studied the normal counterpart in which the gene was normally expressed. (b) Examples of immunohistochemical detection of MITOSTATIN in human breast and bladder. MITOSTATIN cytoplasmatic staining was observed in normal breast (upper left panel) and bladder (upper right panel) human specimens. Normal mammary glands show a very intense MITOSTATIN-staining in both cytoplasm and cellular membrane (upper left panel). Examples of MITOSTATIN positive breast (middle left panel) and bladder (middle right panel) cancers and negative breast (lower left panel) and bladder (lower right panel) tumors. (X400). (c) MITOSTATIN immunohistochemical expression is decreased in advanced stages in breast and prostate. The distribution of the immunohistochemical scores in the different tumor stages is shown. Original magnifications 10x, 20x and 40x.
Mentions: To determine whether MITOSTATIN is mutated or lost in malignant human tumors, we performed a systematic analysis of cancer-derived cell lines and solid tumors using RT-PCR. MITOSTATIN mRNA was absent in ~6% of the cancer samples (1 vulva, 2 colon and 3 prostate cancers; 4.2% including the cancer cell lines). Also in the three prostate samples, we studied the normal counterpart in which the gene was normally expressed (Figure 8a). Four point mutations were detected (Figure S8). In the gastric carcinoma derived RF48 cell line, T345 in exon 2 was substituted in heterozygosity by a C, changing the aminoacid from a serine to a proline (S44P). In the prostate derived LNCaP cell line, C 184 in exon 9 was substituted in heterozygosity by a T, without aminoacid changes (A323A). In the pancreatic carcinoma derived SU86 cell line, G 890 in exon 6 was substituted in heterozygosity by an A, without changing the glutamic acid (E225E). In the CAPAN1 pancreatic carcinoma derived cells, C 492 in exon 3 was homozygously mutated to A, changing the aminoacid from glutamic acid to lysine (E93K). Notably, all these mutations affected aminoacid residues that are highly conserved in evolution (Figure 1c and Figure S8). In immunofluorence confocal analysis MITOSTATIN still showed a punctuate pattern of distribution and co-localized within mitochondria in LNCaP (Figure S5), CAPAN and Su86.

Bottom Line: Human MITOSTATIN was found within a 3.2-kb transcript, which encoded a approximately 62 kDa, ubiquitously expressed protein with little homology to any known protein.We found homozygous deletions and mutations of MITOSTATIN gene in approximately 5 and approximately 11% of various cancer-derived cells and solid tumors, respectively.Finally, MITOSTATIN expression was significantly reduced in primary bladder and breast tumors, and its reduction was associated with advanced tumor stages.

View Article: PubMed Central - PubMed

Affiliation: Department of Urology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA.

ABSTRACT
Allelic deletions on human chromosome 12q24 are frequently reported in a variety of malignant neoplasms, indicating the presence of a tumor suppressor gene(s) in this chromosomal region. However, no reasonable candidate has been identified so far. In this study, we report the cloning and functional characterization of a novel mitochondrial protein with tumor suppressor activity, henceforth designated MITOSTATIN. Human MITOSTATIN was found within a 3.2-kb transcript, which encoded a approximately 62 kDa, ubiquitously expressed protein with little homology to any known protein. We found homozygous deletions and mutations of MITOSTATIN gene in approximately 5 and approximately 11% of various cancer-derived cells and solid tumors, respectively. When transiently overexpressed, MITOSTATIN inhibited colony formation, tumor cell growth and was proapoptotic, all features shared by established tumor suppressor genes. We discovered a specific link between MITOSTATIN overexpression and downregulation of Hsp27. Conversely, MITOSTATIN knockdown cells showed an increase in cell growth and cell survival rates. Finally, MITOSTATIN expression was significantly reduced in primary bladder and breast tumors, and its reduction was associated with advanced tumor stages. Our findings support the hypothesis that MITOSTATIN has many hallmarks of a classical tumor suppressor in solid tumors and may play an important role in cancer development and progression.

Show MeSH
Related in: MedlinePlus