Cathepsins mediate tumor metastasis

Table 1 Characters of human cathepsin familymembers

Cathepsin	Subtype	Endo/exopeptidase	Expressed tissue	Function
A	Serine	Exopeptidase	Platelets, primary human antigen presenting cell, testis and epididymis	Autophagy, elastic fiber formation, platelet activation
B	Cysteine	Exo and endo	Widely distributed in macrophages, hepatocytes	Protein catabolism, processing of antigens hormone activation and bone turnover
C	Cysteine	Exo	renal tubules, all endocrine organs Broadly distributed in tissues	Hydrolyze dipeptide esters,amides, anilides and beta-naphtylamides
D	Aspartic	Endo	Eccrine sweat, extracellular matrix and synovial fluid of cartilage	Protein degradation in an acidic milieu of lysosomes
E	Aspartic	Endo	Immune system	Antigen presentation
F	Cysteine	Endo	Antigen presenting cells	Antigen presenting
G	Serine	Endo	Polymorphonuclear leukocyte	Immune complex mediated inflammation production of angiotensin II, degradation of extracellular matrix
H	Cysteine	Endo	Ubiquitous in cells and tissues	Endopeptidase activity
L	Cysteine	Endo	Ubiquitously expressed	Keratinocyte differentiation, protein turnover, antigen presentation
K	Cysteine	Endo	Bone, ovary, heart, placenta, lung, skeletal muscle, colon and small intestine	Bone remodeling
O	Cysteine	Endo	Broadly distributed in tissues	Protein degradation and turnover
S	Cysteine	Endo	Spleen and professional antigen-presenting cells	Ii chain proteolysis
V	Cysteine	Endo	Thymus and testis, corneal epithelium	Production of enkephalin and neuropeptide Y
W	Cysteine	Endo	T-lymphocytes	Cell-mediated cytotoxicity
X	Cysteine	Endo	Immune system	Phagocytosis, regulation of immune responses
Z	Cysteine	Exo	Widely expressed in human tissues	Protein degradation

Table 2 Cathepsin family members expressed in cancers

Cathepsin	Elevated in cancer	Location of cancer
A	Yes	Malignant melanoma
B	Yes	Breast carcinomas, melanoma, gastric cancer, lung cancer, colon cancer, ovarian cancer, cervical cancer pancreatic carcinomas, glioblastoma thyroid carcinoma,cholangiocarcinomas, hepatocellular carcinomas, bladder caner
C	Unclear
D	Yes	Thyroid carcinomas, squamous cell carcinoma, renal cell, carcinoma, glioma brain tumors, laryngeal carcinoma, breast cancer, lung cancer, ovarian carcinoma
E	Yes	Pancreatic ductal adenocarcinoma, gastric cancer
F	Yes	cervical carcinoma
G	Yes	Breast cancer
H	Yes	Breast carcinoma, colorectal cancer, melanoma, head and neck carcinoma, glioma, prostate cancer
L	Yes	Breast cancer, lung cancer, gastric cancer, colon cancer, head and neck carcinomas, melanomas, gliomas, ovarian cancer, pancreatic cancer
K	Yes	Gastric cancer, squamous cell carcinoma, basal cell carcinoma, breast tumor, lung cancer, melanomas, prostate tumors, renal tumor
O	Unclear
S	Yes	Astrocytoma, gastric cancer, hepatocellular carcinomas, glioblastomas, melanoma, gastric cancer, pancreatic islet cell cancer
V	Unclear
W	Unclear
X	Yes	Prostate cancer, gastric cancer, malignant melanomas, prostate cancer, lung tumors, breast cancer, colonrectal cancer
Z	Yes	Melanomas, gastric cancer, hepatocellular carcinomas, pancreatic carcinomas