Review



murine pituitary corticotrophin tumor cell line att  (ATCC)


Bioz Verified Symbol ATCC is a verified supplier
Bioz Manufacturer Symbol ATCC manufactures this product  
  • Logo
  • About
  • News
  • Press Release
  • Team
  • Advisors
  • Partners
  • Contact
  • Bioz Stars
  • Bioz vStars
  • 95

    Structured Review

    ATCC murine pituitary corticotrophin tumor cell line att
    Murine Pituitary Corticotrophin Tumor Cell Line Att, supplied by ATCC, used in various techniques. Bioz Stars score: 95/100, based on 350 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
    https://www.bioz.com/product/pituitary+tumor+cell+line/AtT-20/10__1186_slash_s12575___026___00359___9-61-12-23
    Average 95 stars, based on 350 article reviews
    murine pituitary corticotrophin tumor cell line att - by Bioz Stars, 2026-11
    95/100 stars

    Images

    Related Articles

    other:

    Article Title: Protein kinase C delta mediates Pasireotide effects in an ACTH-secreting pituitary tumor cell line
    Article Snippet: The mouse ACTH-secreting pituitary tumor cell line, AtT-20/D16v-F2 (ATCC CRL-1795, American Type Culture Collection, Manassas, Virginia, USA), was maintained at 37 °C, 5% CO 2 in DMEM high glucose (Invitrogen, Carlsbad, California, USA) supplemented with 10% horse serum (LGC Standards, Milan, Italy) and antibiotic/antimycotic (EuroClone, Milan, Italy).

    Article Title: Protein kinase C delta mediates Pasireotide effects in an ACTH-secreting pituitary tumor cell line.
    Article Snippet: The mouse ACTH-secreting pituitary tumor cell line, AtT20/D16v-F2 (ATCC CRL-1795, American Type Culture Collection, Manassas, Virginia, USA), was maintained at 37 °C, 5% CO2 in DMEM high glucose (Invitrogen, Carlsbad, California, USA) supplemented with 10% horse serum (LGC Standards, Milan, Italy) and antibiotic/antimycotic (EuroClone, Milan, Italy).

    Cell Culture:

    Article Title: TNF-α-Induced VEGF and MMP-9 Expression Promotes Hemorrhagic Transformation in Pituitary Adenomas
    Article Snippet: .. MMQ, a rat prolactin-secreting pituitary tumor cell line, was purchased from ATCC (American Type Culture Collection, Manassas, VA) and routinely cultured in F-12 medium supplemented with 2.5% fetal bovine serum and 15% equine serum at 37 °C in a humidified air atmosphere containing 5% carbon dioxide in T-75 flasks. .. MMQ cells were stimulated with 20 ng/mL TNF-α (Abcam) or saline for 24 h, and then were analyzed for possible effects of TNF-α on VEGF and MMP-9 expression.



    Similar Products

    95
    ATCC murine pituitary corticotrophin tumor cell line att
    Murine Pituitary Corticotrophin Tumor Cell Line Att, supplied by ATCC, used in various techniques. Bioz Stars score: 95/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
    https://www.bioz.com/product/pituitary+tumor+cell+line/AtT-20/10__1186_slash_s12575___026___00359___9-61-12-23
    Average 95 stars, based on 1 article reviews
    murine pituitary corticotrophin tumor cell line att - by Bioz Stars, 2026-11
    95/100 stars
      Buy from Supplier

    96
    ATCC rat pituitary tumor cell line gh3
    Rat Pituitary Tumor Cell Line Gh3, supplied by ATCC, used in various techniques. Bioz Stars score: 96/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
    https://www.bioz.com/product/pituitary+tumor+cell+line/GH3/10__1186_slash_s12575___026___00359___9-61-5-23
    Average 96 stars, based on 1 article reviews
    rat pituitary tumor cell line gh3 - by Bioz Stars, 2026-11
    96/100 stars
      Buy from Supplier

    86
    Procell Inc rat pituitary tumor cell lines
    Rat Pituitary Tumor Cell Lines, supplied by Procell Inc, used in various techniques. Bioz Stars score: 86/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
    https://www.bioz.com/product/pituitary+tumor+cell+line/breast+cancer+cell+human+lines/pm41930558-38-0-12
    Average 86 stars, based on 1 article reviews
    rat pituitary tumor cell lines - by Bioz Stars, 2026-11
    86/100 stars
      Buy from Supplier

    86
    Procell Inc rat pituitary tumor cell line gh3
    Rat Pituitary Tumor Cell Line Gh3, supplied by Procell Inc, used in various techniques. Bioz Stars score: 86/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
    https://www.bioz.com/product/pituitary+tumor+cell+line/breast+cancer+cell+human+lines/pm41864412-70-1-10
    Average 86 stars, based on 1 article reviews
    rat pituitary tumor cell line gh3 - by Bioz Stars, 2026-11
    86/100 stars
      Buy from Supplier

    95
    ATCC gh3 epithelial like rat pituitary tumor cell line
    Gh3 Epithelial Like Rat Pituitary Tumor Cell Line, supplied by ATCC, used in various techniques. Bioz Stars score: 95/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
    https://www.bioz.com/product/pituitary+tumor+cell+line/GH1/arxiv__2603__00709-362-3-10
    Average 95 stars, based on 1 article reviews
    gh3 epithelial like rat pituitary tumor cell line - by Bioz Stars, 2026-11
    95/100 stars
      Buy from Supplier

    90
    Procell Inc ttt/gf pituitary tumor cell line
    a CCK-8 cell viability assay of GH3, <t>AtT-20,</t> and TtT/GF cells treated with OPN or PBS ( n = 5 biological replicates). Data are presented as mean values +/- SD. b Representative images of the wound healing assay, and ( c ) quantitative analysis of TtT/GF cells treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. d Transwell invasion assay and ( e ) quantitative analysis of GH3, AtT-20, and TtT/GF cells treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. f Immunofluorescence images of PitNET markers (SYN, SF1, FSH) in PitNET organoids from two independent patients ( n = 3 biological replicates). g Transwell invasion assay and ( h ) quantitative analysis of primary pituitary tumor cells cultured from two independent patients, treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. i Bright-field images illustrating representative phenotypes of three independently derived PitNET organoids from each of the two patients treated with OPN or PBS. Arrows indicate cell protrusions in PitNET organoids. j CellTiter-Glo luminescent cell viability assay of PitNET organoids treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. k Immunofluorescence images of Ki67 in PitNET organoids from two patients treated with OPN or PBS ( n = 3 biological replicates). For all panels, scale bar, 100 µm. Two-sided unpaired t -test was performed for ( a − j ). Data are presented as mean values +/- SD for ( a − j ). Source data are provided as a Source Data file for ( a − j ).
    Ttt/Gf Pituitary Tumor Cell Line, supplied by Procell Inc, used in various techniques. Bioz Stars score: 90/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
    https://www.bioz.com/product/pituitary+tumor+cell+line/rat+pituitary+tumor+gh3+cells/pmc12122724-361-1-5
    Average 90 stars, based on 1 article reviews
    ttt/gf pituitary tumor cell line - by Bioz Stars, 2026-11
    90/100 stars
      Buy from Supplier

    95
    ATCC pituitary tumor cell lines att 20
    a CCK-8 cell viability assay of GH3, <t>AtT-20,</t> and TtT/GF cells treated with OPN or PBS ( n = 5 biological replicates). Data are presented as mean values +/- SD. b Representative images of the wound healing assay, and ( c ) quantitative analysis of TtT/GF cells treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. d Transwell invasion assay and ( e ) quantitative analysis of GH3, AtT-20, and TtT/GF cells treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. f Immunofluorescence images of PitNET markers (SYN, SF1, FSH) in PitNET organoids from two independent patients ( n = 3 biological replicates). g Transwell invasion assay and ( h ) quantitative analysis of primary pituitary tumor cells cultured from two independent patients, treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. i Bright-field images illustrating representative phenotypes of three independently derived PitNET organoids from each of the two patients treated with OPN or PBS. Arrows indicate cell protrusions in PitNET organoids. j CellTiter-Glo luminescent cell viability assay of PitNET organoids treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. k Immunofluorescence images of Ki67 in PitNET organoids from two patients treated with OPN or PBS ( n = 3 biological replicates). For all panels, scale bar, 100 µm. Two-sided unpaired t -test was performed for ( a − j ). Data are presented as mean values +/- SD for ( a − j ). Source data are provided as a Source Data file for ( a − j ).
    Pituitary Tumor Cell Lines Att 20, supplied by ATCC, used in various techniques. Bioz Stars score: 95/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
    https://www.bioz.com/product/pituitary+tumor+cell+line/AtT-20%2FD16v-F2/pmc12122724-360-0-4
    Average 95 stars, based on 1 article reviews
    pituitary tumor cell lines att 20 - by Bioz Stars, 2026-11
    95/100 stars
      Buy from Supplier

    90
    Procell Inc pituitary tumor cell line ttt/gf
    a CCK-8 cell viability assay of GH3, <t>AtT-20,</t> and TtT/GF cells treated with OPN or PBS ( n = 5 biological replicates). Data are presented as mean values +/- SD. b Representative images of the wound healing assay, and ( c ) quantitative analysis of TtT/GF cells treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. d Transwell invasion assay and ( e ) quantitative analysis of GH3, AtT-20, and TtT/GF cells treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. f Immunofluorescence images of PitNET markers (SYN, SF1, FSH) in PitNET organoids from two independent patients ( n = 3 biological replicates). g Transwell invasion assay and ( h ) quantitative analysis of primary pituitary tumor cells cultured from two independent patients, treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. i Bright-field images illustrating representative phenotypes of three independently derived PitNET organoids from each of the two patients treated with OPN or PBS. Arrows indicate cell protrusions in PitNET organoids. j CellTiter-Glo luminescent cell viability assay of PitNET organoids treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. k Immunofluorescence images of Ki67 in PitNET organoids from two patients treated with OPN or PBS ( n = 3 biological replicates). For all panels, scale bar, 100 µm. Two-sided unpaired t -test was performed for ( a − j ). Data are presented as mean values +/- SD for ( a − j ). Source data are provided as a Source Data file for ( a − j ).
    Pituitary Tumor Cell Line Ttt/Gf, supplied by Procell Inc, used in various techniques. Bioz Stars score: 90/100, based on 1 PubMed citations. ZERO BIAS - scores, article reviews, protocol conditions and more
    https://www.bioz.com/product/pituitary+tumor+cell+line/rat+pituitary+tumor+gh3+cells/pm40442104-364-1-5
    Average 90 stars, based on 1 article reviews
    pituitary tumor cell line ttt/gf - by Bioz Stars, 2026-11
    90/100 stars
      Buy from Supplier

    Image Search Results


    a CCK-8 cell viability assay of GH3, AtT-20, and TtT/GF cells treated with OPN or PBS ( n = 5 biological replicates). Data are presented as mean values +/- SD. b Representative images of the wound healing assay, and ( c ) quantitative analysis of TtT/GF cells treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. d Transwell invasion assay and ( e ) quantitative analysis of GH3, AtT-20, and TtT/GF cells treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. f Immunofluorescence images of PitNET markers (SYN, SF1, FSH) in PitNET organoids from two independent patients ( n = 3 biological replicates). g Transwell invasion assay and ( h ) quantitative analysis of primary pituitary tumor cells cultured from two independent patients, treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. i Bright-field images illustrating representative phenotypes of three independently derived PitNET organoids from each of the two patients treated with OPN or PBS. Arrows indicate cell protrusions in PitNET organoids. j CellTiter-Glo luminescent cell viability assay of PitNET organoids treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. k Immunofluorescence images of Ki67 in PitNET organoids from two patients treated with OPN or PBS ( n = 3 biological replicates). For all panels, scale bar, 100 µm. Two-sided unpaired t -test was performed for ( a − j ). Data are presented as mean values +/- SD for ( a − j ). Source data are provided as a Source Data file for ( a − j ).

    Journal: Nature Communications

    Article Title: Single-cell and spatial transcriptome analyses reveal tumor heterogeneity and immune remodeling involved in pituitary neuroendocrine tumor progression

    doi: 10.1038/s41467-025-60028-5

    Figure Lengend Snippet: a CCK-8 cell viability assay of GH3, AtT-20, and TtT/GF cells treated with OPN or PBS ( n = 5 biological replicates). Data are presented as mean values +/- SD. b Representative images of the wound healing assay, and ( c ) quantitative analysis of TtT/GF cells treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. d Transwell invasion assay and ( e ) quantitative analysis of GH3, AtT-20, and TtT/GF cells treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. f Immunofluorescence images of PitNET markers (SYN, SF1, FSH) in PitNET organoids from two independent patients ( n = 3 biological replicates). g Transwell invasion assay and ( h ) quantitative analysis of primary pituitary tumor cells cultured from two independent patients, treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. i Bright-field images illustrating representative phenotypes of three independently derived PitNET organoids from each of the two patients treated with OPN or PBS. Arrows indicate cell protrusions in PitNET organoids. j CellTiter-Glo luminescent cell viability assay of PitNET organoids treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. k Immunofluorescence images of Ki67 in PitNET organoids from two patients treated with OPN or PBS ( n = 3 biological replicates). For all panels, scale bar, 100 µm. Two-sided unpaired t -test was performed for ( a − j ). Data are presented as mean values +/- SD for ( a − j ). Source data are provided as a Source Data file for ( a − j ).

    Article Snippet: The pituitary tumor cell line TtT/GF(Procell, CL-0561) is cultured in DMEM/F12 medium supplemented with 10% horse serum, 2.5% FBS, 2 ng/ml basic fibroblast growth factor (bFGF), and 1% penicillin-streptomycin (Procell, CM-0561).

    Techniques: CCK-8 Assay, Viability Assay, Wound Healing Assay, Transwell Invasion Assay, Immunofluorescence, Cell Culture, Derivative Assay, Cell Viability Assay

    a Western blot analysis of ITGB1 expression in GH3, AtT-20, and TtT/GF cell lines. b Semi-quantitative analysis of ITGB1 in GH3, AtT-20, and TtT/GF cell lines ( n = 3 biological replicates). c CCK-8 cell viability assay of GH3, AtT-20, and TtT/GF cell lines under specified treatments ( n = 3 biological replicates). d Transwell invasion assay of GH3, AtT-20, and TtT/GF cell lines under specified treatments ( n = 3 biological replicates). e Quantitative analysis of Transwell invasion assay in GH3, AtT-20, and TtT/GF cell lines under specified treatments ( n = 3 biological replicates). Scale bar, 100 µm. Two-sided unpaired t -test was performed for ( b − e ). Data are presented as mean values +/- SD for ( b − e ). Source data are provided as a Source Data file for ( a − e ).

    Journal: Nature Communications

    Article Title: Single-cell and spatial transcriptome analyses reveal tumor heterogeneity and immune remodeling involved in pituitary neuroendocrine tumor progression

    doi: 10.1038/s41467-025-60028-5

    Figure Lengend Snippet: a Western blot analysis of ITGB1 expression in GH3, AtT-20, and TtT/GF cell lines. b Semi-quantitative analysis of ITGB1 in GH3, AtT-20, and TtT/GF cell lines ( n = 3 biological replicates). c CCK-8 cell viability assay of GH3, AtT-20, and TtT/GF cell lines under specified treatments ( n = 3 biological replicates). d Transwell invasion assay of GH3, AtT-20, and TtT/GF cell lines under specified treatments ( n = 3 biological replicates). e Quantitative analysis of Transwell invasion assay in GH3, AtT-20, and TtT/GF cell lines under specified treatments ( n = 3 biological replicates). Scale bar, 100 µm. Two-sided unpaired t -test was performed for ( b − e ). Data are presented as mean values +/- SD for ( b − e ). Source data are provided as a Source Data file for ( a − e ).

    Article Snippet: The pituitary tumor cell line TtT/GF(Procell, CL-0561) is cultured in DMEM/F12 medium supplemented with 10% horse serum, 2.5% FBS, 2 ng/ml basic fibroblast growth factor (bFGF), and 1% penicillin-streptomycin (Procell, CM-0561).

    Techniques: Western Blot, Expressing, CCK-8 Assay, Viability Assay, Transwell Invasion Assay

    a CCK-8 cell viability assay of GH3, AtT-20, and TtT/GF cells treated with OPN or PBS ( n = 5 biological replicates). Data are presented as mean values +/- SD. b Representative images of the wound healing assay, and ( c ) quantitative analysis of TtT/GF cells treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. d Transwell invasion assay and ( e ) quantitative analysis of GH3, AtT-20, and TtT/GF cells treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. f Immunofluorescence images of PitNET markers (SYN, SF1, FSH) in PitNET organoids from two independent patients ( n = 3 biological replicates). g Transwell invasion assay and ( h ) quantitative analysis of primary pituitary tumor cells cultured from two independent patients, treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. i Bright-field images illustrating representative phenotypes of three independently derived PitNET organoids from each of the two patients treated with OPN or PBS. Arrows indicate cell protrusions in PitNET organoids. j CellTiter-Glo luminescent cell viability assay of PitNET organoids treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. k Immunofluorescence images of Ki67 in PitNET organoids from two patients treated with OPN or PBS ( n = 3 biological replicates). For all panels, scale bar, 100 µm. Two-sided unpaired t -test was performed for ( a − j ). Data are presented as mean values +/- SD for ( a − j ). Source data are provided as a Source Data file for ( a − j ).

    Journal: Nature Communications

    Article Title: Single-cell and spatial transcriptome analyses reveal tumor heterogeneity and immune remodeling involved in pituitary neuroendocrine tumor progression

    doi: 10.1038/s41467-025-60028-5

    Figure Lengend Snippet: a CCK-8 cell viability assay of GH3, AtT-20, and TtT/GF cells treated with OPN or PBS ( n = 5 biological replicates). Data are presented as mean values +/- SD. b Representative images of the wound healing assay, and ( c ) quantitative analysis of TtT/GF cells treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. d Transwell invasion assay and ( e ) quantitative analysis of GH3, AtT-20, and TtT/GF cells treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. f Immunofluorescence images of PitNET markers (SYN, SF1, FSH) in PitNET organoids from two independent patients ( n = 3 biological replicates). g Transwell invasion assay and ( h ) quantitative analysis of primary pituitary tumor cells cultured from two independent patients, treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. i Bright-field images illustrating representative phenotypes of three independently derived PitNET organoids from each of the two patients treated with OPN or PBS. Arrows indicate cell protrusions in PitNET organoids. j CellTiter-Glo luminescent cell viability assay of PitNET organoids treated with OPN or PBS ( n = 3 biological replicates). Data are presented as mean values +/- SD. k Immunofluorescence images of Ki67 in PitNET organoids from two patients treated with OPN or PBS ( n = 3 biological replicates). For all panels, scale bar, 100 µm. Two-sided unpaired t -test was performed for ( a − j ). Data are presented as mean values +/- SD for ( a − j ). Source data are provided as a Source Data file for ( a − j ).

    Article Snippet: Pituitary tumor cell lines AtT-20(ATCC, CRL-1795), GH3(ATCC, CCL-82.1) were cultured in DMEM (ThermoFisher, 11995065) medium supplemented with 10% fetal bovine serum (FBS) (ThermoFisher, 10270106) and 1% penicillin-streptomycin (ThermoFisher, 15070063) under standard conditions of 37 °C in a humidified incubator with 5% CO 2 .

    Techniques: CCK-8 Assay, Viability Assay, Wound Healing Assay, Transwell Invasion Assay, Immunofluorescence, Cell Culture, Derivative Assay, Cell Viability Assay

    a Western blot analysis of ITGB1 expression in GH3, AtT-20, and TtT/GF cell lines. b Semi-quantitative analysis of ITGB1 in GH3, AtT-20, and TtT/GF cell lines ( n = 3 biological replicates). c CCK-8 cell viability assay of GH3, AtT-20, and TtT/GF cell lines under specified treatments ( n = 3 biological replicates). d Transwell invasion assay of GH3, AtT-20, and TtT/GF cell lines under specified treatments ( n = 3 biological replicates). e Quantitative analysis of Transwell invasion assay in GH3, AtT-20, and TtT/GF cell lines under specified treatments ( n = 3 biological replicates). Scale bar, 100 µm. Two-sided unpaired t -test was performed for ( b − e ). Data are presented as mean values +/- SD for ( b − e ). Source data are provided as a Source Data file for ( a − e ).

    Journal: Nature Communications

    Article Title: Single-cell and spatial transcriptome analyses reveal tumor heterogeneity and immune remodeling involved in pituitary neuroendocrine tumor progression

    doi: 10.1038/s41467-025-60028-5

    Figure Lengend Snippet: a Western blot analysis of ITGB1 expression in GH3, AtT-20, and TtT/GF cell lines. b Semi-quantitative analysis of ITGB1 in GH3, AtT-20, and TtT/GF cell lines ( n = 3 biological replicates). c CCK-8 cell viability assay of GH3, AtT-20, and TtT/GF cell lines under specified treatments ( n = 3 biological replicates). d Transwell invasion assay of GH3, AtT-20, and TtT/GF cell lines under specified treatments ( n = 3 biological replicates). e Quantitative analysis of Transwell invasion assay in GH3, AtT-20, and TtT/GF cell lines under specified treatments ( n = 3 biological replicates). Scale bar, 100 µm. Two-sided unpaired t -test was performed for ( b − e ). Data are presented as mean values +/- SD for ( b − e ). Source data are provided as a Source Data file for ( a − e ).

    Article Snippet: Pituitary tumor cell lines AtT-20(ATCC, CRL-1795), GH3(ATCC, CCL-82.1) were cultured in DMEM (ThermoFisher, 11995065) medium supplemented with 10% fetal bovine serum (FBS) (ThermoFisher, 10270106) and 1% penicillin-streptomycin (ThermoFisher, 15070063) under standard conditions of 37 °C in a humidified incubator with 5% CO 2 .

    Techniques: Western Blot, Expressing, CCK-8 Assay, Viability Assay, Transwell Invasion Assay