Cell motility

and the extracellular

matrix

B.R. Zetter and S.E. Brightman Department of Cellular and Molecular and Department of Surgery, Children’s Current

Opinion

Physiology, Harvard Medical School Hospital, Boston, Massachusetts, USA

in Cell Biology

Introduction

are not adhesive and therefore are unlikely to provide a haptotactic stimulus. The same is true for the elastinderived peptide Val-GlyVal-Ala-Pro-Gly (VGVAPG) which stimulates directional, but not random, motility of tumor cells and possesses no adhesive activity for these cells (Yusa et al, Am Rev Respir Dis 1989, 140:1458-1462). In contrast, several ECM molecules exhibit combined adhesion and migration activities, making it dilficult to determine the relative contributions of haptotaxis and chemotaxis to the response that they elicit.

Extracellular matrix (ECM) molecules were first studied with regard to their role in maintaining tissue structure and integrity. More recently, greater attention has been paid to the adhesive properties of matrix molecules and to the speciIic domains within them that mediate adhesive functions. As information about the structure and adhesive function of the ECM has emerged, it has become apparent that many ECM molecules can modulate the motile responses of a variety of cell types either clrectly or indirectly. In this review, we will discuss the particular matrix domains that influence cell motility, the cellular receptors that respond to these molecules and the signal transduction mechanisms that mediate the motile response.

Random

versus oriented

Chemotaxis to ECM molecules has been measured most often using the ‘Boyden chamber’ assay, in which a porous filter separates the cells in an upper compartment from a soluble chemoattractant present in a lower compartment (Boyden, J Exp Med 1962,115:435-466). Migration of cells through the pores to the underside of the filter is taken to represent a chemotactic response. Haptotaxis, on the other hand, has been measured using a modified Boyden chamber assay in which the underside of the filter is coated to generate a ‘step gradient’ of an anchored attractant. Passage of cells from the top of the lilter to the bottom has been interpreted as a haptotactic response for molecules such as fibronectin (McCarthy and Furcht, J Cell Biof 1984, 98:1474-1480) [l], laminin (McCarthy et al., J Cell Bioll983, 97:772-777) [ 11, collagen types I and IV [ 1,2], and thrombospondin (Taraboletti et al, J Cell Bioll987, 105:24092415).

motility

Before we begin our discussion of the motile response to ECM components, it is Important to make the distinction between random motility (chemokinesis), chemotaxis, and haptotaxis. Because the matrix protein domains and cell-surface receptors involved in ECM-promoted motility for the most part also function in cell adhesion, dissection of the mechanisms underlying these different classes of motile response has proved difficult.

In a recent innovative study, Brandley and Schnaar [3] have shown that a purely haptotactic response can be observed by creating solid-phase gradients of attractams in a polyacrylamide gel. Cells were plated on the gel at uniform density and Incubated for several hours. Computer-generated cell density profiles revealed that BlGFlO melanoma cells plated on a gradient of immobilized RGD-peptide redistributed towards higher immobilized peptide concentrations, whereas cells plated on non-gradient control gels exhibited no significant redistribution [3].

Chemokinesis is the term for induction of cell locomotion without any orienting cues, i.e. the transition from the non-motile to the motile state. Chemotaxis and haptotaxis represent the response to signals that orient moving cells along a gradient. Chemotaxis describes the directed migration of cells towards a positive gradient of soluble attractant, whereas haptotaxis describes the directed migration of cells along a gradient of an anchored molecule. The directional movement of neutrophils to formyl peptides such as formyl-Met-Ieu-Phe (IMLF) is considered as chemotaxis because cell movement proceeds in the direction of a soluble gradient and because the peptides

HOS-human

ECM-extracellular osteosarcoma;

The novel assay developed by Brandley and Schnaar (31 permits the study of haptotactic activity in the absence

Abbreviations matrix; GalTase-p-1,4-galactosyltransferase; MNNG-N-methyl-N’-nitro-N-nitrosoguanidine;

@

Current

Biology

1990, 2:85@856

Ltd

C-proteiMTP-binding TPA-12-O-tetradecanoyl

ISSN

0955+674

protein; phorbol

12-acetate.

Cell motility

of a soluble chemotactic stimulus. It is perhaps more difficult to study the soluble chemotactic activity of a molecule that also has an adhesive function. This is because of the difficulty of designing an assay which measures the soluble chemotactic activity of a peptide while preventing it from forming an adhesive, haptotactic gradient. In the sections below, we will indicate in which studies the distinction between the haptotactic, chemotactic and chemokinetic activities of ECM proteins and their component peptides have been adequately made.

Matrix

molecules

involved

in cell motility

Several ECM molecules can influence the motility of a variety of cell types. The best studied of these molecules are fibronectin, laminin, collagen, elastin, and thrombospondin. In the past two years, great progress has been made in identifying sequences within these molecules that promote ceU motility and in identifying the cellular receptors that interact with these peptide sequences.

and the extracellular

matrix

Zetter

and Brightman

48:98%996), cardiac mesenchymal cells [6] and neural crest cells (Bilozur et al, Dev Bioi 1988, 125:1+33). It has been reported that a second sequence in the Bl chain, Leu-Gly-Thr-Ile-Pro-Gly (LGTIPG) stimulates chemotaxis of ligament fibroblasts and A2058 melanoma cells [7]. An additional laminin domain that promotes motility is the E8 fragment which mediates neurite outgrowth of PC12 cells and migration of BlG-FlO melanoma cells [8], rat rhabdomyosarcoma cells [9], and neural crest cells [4]. The motility-promoting site within the E8 domain has been localized to a IPamino-acid peptide referred to as PA22-2. The pentapeptide sequence Ile-Lys-Val-AlaVal (IKVAV) located within PA22-2 exhibits both adhesion and motility-promoting activity [8]. The lamininderived peptides described above exhibit only part of the motility-stimulating activity of intact laminin, suggesting either that multiple sites are required for maximal activity or that the steric presentation of the individual sequences is optimal in the intact molecule.

Collagen Fibronectin

The motility-stimulating properties of fibronectin were first established more than a decade ago (Ali et al, Cell 1978, 14:43!&446). The fibronectin domain that has received the most attention for its effects on cell motility is the Arg-Gly-Asp-Ser (RGDS) sequence, which also possesses adhesion-promoting activity (Albini et al., J Cell Biol 1987, 105:1867-1872). Synthetic RGD-containing peptides have been shown to inhibit partially ceUular migration on fibronectin substrates (Straus et al., Exp Cell Res 1989, 183:126139) [4,5]. The fact that RGD-containing sequences only partially inhibit cell motility on fibronectin suggests that other determinants within the fibronectin molecule may be involved. Other libronectin domains have, in fact, been shown to stimulate or modulate neurite outgrowth as weU as migration of embryonic neural crest cells. These sites include the principal heparin-binding domain II and the CSl ceU adhesive site (Dufour et al, EMBOJ 1988,7:2661-2671; Humphries et al, J Cell Biol1988, 156:1289-1298) [4]. Detailed information on the structure of fibronectin domains can be found in a recent review by Akiyama and Yamada (A&p Enzymol1989, 57:1-57).

Early studies of the motility-promoting activities of collagen revealed that collagen types I-III and collagen peptide fragments stimulated migration of fibroblasts (Postlethwaite et al, Pm Nutl Acud Sci USA 1978, 75:871-875) and monocytes (Postlethwaite et a.!, J Exp Med 1976, 143:1299-1307). Mundy and colleagues (I Clin Inzfest 1981,68:1102-1106) found that fragments of types I and III collagen stimulated chemotaxis of Walker rat carcinoma cells and that this activity could be attributed in part to the di- and tripeptide collagen sequences Gly-Pro (GP) and Gly-Pro-Ala (GPA). More recently, Chelberg and colleagues [2,10] have reported that melanoma cells respond to types I and IV collagen in Boyden chamber chemotaxis and haptotaxis assays. For type IV collagen, migration-stimulating activity was associated with the major triple helical region of the molecule (p-IV) and not with the carboxylterminal NC1 region [2]. Further dissection of the p-IV region rwealed that the migration-stimulating activity was associated with the sequence Gly-Val-Lys-Gly-Asp-LysGly-Asn-Pro-Gly-TV-Pro-GlyAla-Pro (GVKGDKGNPGWPGAP) [lo]. Amino acid substitutions to this sequence show that the prolyl residues are necessary for the motile response to this peptide [lo].

laminin

Several different domains of the laminin protein have been implicated in regulating cell motility. One might expect that the RGD sequence located in the A chain mediates the motile response to laminin (Sasaki et al, J Biol Chem 1988, 26331653616544). Synthetic RGDcontaining peptides do not, however, consistently block laminin-induced motility (Wewer et cd., Cancer Res 1987, 47:5691-5698) [ 1,5,6]. The weU studied Tyr-Ile-Gly-SerArg (YIGSR) motif found in the cysteine-rich region of the Bl short-chain of laminin stimulates migration of several ceU types including tumor cells (Graf et al, Cell 1987,

Elastin

Although mature, crosslinked e&tin is an insoluble molecule, acid-solubilized a-elastin and non-crosslinked tropoelastin monomer have both been shown to stimulate motility of a variety of ceU types including monocytes (Senior et al., J Clin Invest 1980, 66:85-62), ligament fibroblasts (Senior et al, J Clin Invest 1982, 70:614-618) and tumor cells [ 7,111. The best characterized elastin domain associated with chemotaxis-stimulating activity is the repeated sequence VGVAPG (Senior et al, J Cell Biol 1984, 99:870-874) [7,11], although other hydrophobic

851

852

Cell-to-cell

contact

and the extracellular

matrix

sequences found in the e&tin molecule may also display some activity (Long et al, Biccbim Biobbys Acta 1988, 968:300-311).

Cell-surface receptors ECM-mediated motility lntegrin

Thrombospondin

Thrombospondin has been reported to stimulate migration of normal epidemral keratinocytes (Nickoloff et al, Am J Path01 1988, 132:543-551) and a variety of tumor cells (Taraboletti et al, J Cell Bioll987, 105:240+2415; Roberts, Cancer Res 1988, 48:6785-6793). In addition, O’Shea et aL [ 121 have provided evidence recently that thrombospondin influences granule cell migration during histogenesis of the cerebellar cortex.

Table

1. Peptide

motifs

involved

in extracellular

molecule

Peptide

Fibronectin

motif

RCDS”s’

Laminin

YlCSRt IKVAVtal LGTIPGf’l

Collagen

GPZ CPA: GVKGDKGNPGWPGAPt’“f

17.111

VGVApGii

Elastin

AGVPGFGVGT GFGVGAGVPI Thrombospondin

Unknown

Vitronectin

Unknown

The single

letter

amino-acid

1987, 105:1867-1872; / C/in /west 874; ILong

tGraf

code

1981, 68:1102-1105; et al., Biochim

is used

here.

‘Albini

et al., Cell 1987, 48:98+996; Eiophys

“Senior

et al., / Cell Rio/ IMundy

in

receptors

Members of the ‘integrin’ family of cell-surface proteins are perhaps the best characterized receptors involved in ECM-mediated motility. Integrins are heterodimers comprised of different a and p subunits (for a review see Akiyama et al, Biochim BiopbysActa 1990, 1031:91-110). The pl integrins appear to be especially important in ECM-mediated motility. Anti-p1 monoclonal antibody inhibits migration of normal, transformed, and tumor cells on laminin or fibronectin-coated substrates [ 5,131 as well as cellular migration (invasion> into collagen gels or matrigel-coated filters [ 51. Many of the pl integrins are specific for a particular ECM molecule. For instance, monoclonal antibody (mAb) 16, directed against the a5 subunit of the fibronectin receptor (aSpl>, modulates cell migration on fibronectin but not on other substrates [5,13]. Interestingly, m~bl6 inhibits migration of SV40-transformed W-38 lung fibroblasts (VA131 on fibronectin-coated surfaces [5] whereas it stimulates migration of non-transformed WI-38 cells [ 131. m~bl6 has no effect on migration of 5637 bladder carcinoma cells on libronectin-coated surfaces [5], emphasizing the cell-type specificity of receptor interactions involved in the motile response.

matrix-stimulated

motility.

Matrix

involved

ef al.,

et al., / Cell Rio/ 1984, 99:870-

Acfa 1988, 968:300-311.

Using monoclonal antibodies as probes of function, Taraboletti and colleagues (1987) demonstrated that dif ferent domains of thrombospondin may mediate chemotactic versus haptotactic responses. Their results indicated that the heparin-binding amino-terminal domain is responsible for the response to soluble thrombospondin, whereas the globular C-terminal domain may be more important for the response to substratumbound thrombospondin. The matrix-derived peptide sequences associated with cell motility are shown in Table 1. It is of interest that adjacent glycyl and prolyi residues are common to several migration-promoting sequences within laminin, collagen, and elastin.

Monoclonal antibody directed against the pl integrin subunit (mAbl3) blocks cell migration on laminin-coated surfaces as well as on fibronectin-coated surfaces [ 51. Integrins of the 01 family may also be involved to some extent in neurite outgrowth on laminin (Tomaselli et al., J Cell BioIl987, 105:2347-2358). This year, Dedhar and Saulnier [ 141 have reported that high expression of a6pl integrin, a known laminin receptor (Sonnenberg et al., J Cell Biol 1990, 110:2145-21551, is associated with the highly invasive phenotype of chemically transformed osteosarcoma cells. These authors were able to substantially inhibit invasion of osteosarcoma cells through matrigel using a monoclonal antibody directed against the a6 subunit [14]. In a recent thorough study, Yamada et al. [ 51 have investigated whether integrins are also involved in cell motility on collagen or titronectin. They showed that tumor cell migration through collagen gels was blocked by a mAb directed against the a2 subunit of the a2pl integrin (plateletglycoprotein Ia-IIa complex). Migration on vitronectin, in contrast, was shown to be blocked by a mAb directed against the avp3 integrin, a receptor that recognizes the RGD motif in vitronectin (Fytela et al, Proc Nat1 Acud Sci USA 1985, 82:57665770). It is important to note that in all the cases discussed above, the decrease in cell motility observed with antiintegrin antibodies may be secondary to a primary effect on cell adhesion. In each of the migration assays used, cells must move across an adherent substratum. Thus, the response to these antibodies may reflect an alteration in cell adhesivity which, in turn, causes cell motility to be decreased.

Cell motility Non-integrin

receptors

Non-integrin receptors involved in ceU motility on ECM substrates have been identified for laminin and elastin. A laminin-binding protein of A4r 67000 has been described that may mediate the migration of some tumor cells on laminin (Wewer et al, 1987) as weU as neurite outgrowth on laminin (Kleinman et al, Proc Nat1 Acad Sci LJX41988, 85:1282-1286). Immunohistochernical studies have revealed that the 67 000 Mr laminin-binding protein is localized to the leading edge of migratory endothelial cells (Yannariello-Brown et al., J Cell Bioll988, 106:1773-1786). This receptor recognizes the laminin pentapeptide MGSR, which has been shown to stimulate Bl6FlO melanoma cell chemotaxis (Graf et al, 1987). The innovative work of Shur and colleagues [ 15,161 suggests that the enzyme P-1,4galactosyi-transferase (GalTase) may have a role in laminin-mediated ceU motility. This enzyme catalyzes the transfer of galactose from UDP-galactose to N-acetyiglucosamine acceptors on intra- and extracellular substrates (Pierce et al., Int Rat Cytoll980, 65:1-47). It is thought to bind to specific Nlinked oligosaccharides within the laminin molecule and thereby promote neurite outgrowth [15,16] and mesenchymal cell migration (Runyan et al, J Cell Bioll986, 102:434-441). Reagents that perturb GalTase function inhibit neurite outgrowth and mesenchymal cell migra tion on laminin but not on fibronectin [15,16]. Most recently, E&stein and Shur [16] have provided evidence that laminin specifically induces translocation of GalTase from intracellular pools into the lamellipodia of migrating mesenchymal cells. A non-integrin cell-surface protein has also been shown to mediate chemotaxis to the elastin peptide VGVAPG. It has been proposed that a galactoside lectin of M, 67 000 triggers migration of A2058 melanoma cells and of ligament fibroblasts in response to the VGVAPG peptide [7,17]. This 67000 M, binding protein shares structural features with the 67 000 M, laminin receptor although absolute homology between the two molecules has not yet been demonstrated. Mecham et al. [7] have proposed that the 67 000 M, elastin-binding protein may recognize both the VGVAPG sequence of elastin and the LGTIPG sequence of laminin and thus act as a bihrnctional mediator of cell motility. Other elastin-binding proteins may also influence ceU motility. A 59000 M, cell-surface VGVAPG-binding protein has been identified on Lewis lung carcinoma sublines by crosslinking with iodinated peptide (Blood et al., J Cell Bioll988, 107:1987-1993). Antibodies to this protein block both VGVAPG binding to M27 cells and chemotaxis to the peptide (Blood and Zetter, unpublished results), implying that this receptor has a role in tumor ceU migration to elastin fragments (Zetter, New Engl J Med 1990, 332:60%612). The receptors associated with ECM-mediated ceU motility are listed in Table 2.

Receptor motility

and the extracellular affinity

modulation:

matrix

Zetter

and Brightman

effects on EC&stimulated

Modulation of ceU surface receptor a&ity for ECM ligands may have important consequences for ECM-stimulated motility. Blood and Zetter [ 111 have compared the motile response of two Lewis lung carcinoma sublines to the e&tin peptide VGVAPG and found that responsiveness correlates with receptor affinity and with levels of membrane-bound protein kinase C. The M27 subline is highly responsive to VGVAPG in Boyden chamber assays, whereas the H59 subline is not. Non-responsive H59 cells have a larger number of VGVAPG binding sites but a lower receptor affinity than M27 cells. After treatment with the phorbol ester 12-Otetradecanoyiphorbol 13.acetate (TPA), H59 cells are able to respond chemotactically to VGVAPG. Binding studies reveal that this increase in chemotactic responsiveness is accompanied by an increase in affinity and a decrease in the absolute number of H59 ceU surface VGVAPG receptors. Examination of protein kinase C levels rev& that TPA-treated H59 cells have higher levels of membrane-associated protein kinase C than untreated H59 cells. These findings demonstrate that the motile response to VGVAPG is dependent on VGVAPG receptor afhnity, which in turn correlates with levels of membrane-associated protein kinase C. It has been observed that phorbol ester treatment of neutrophils has the opposite effect on chemotactic receptor number and atfinity from that observed in H59 cells. Phorbol ester treatment of human neutrophils results in the expression of an increased number of formyl peptide receptors and a decrease in their average affinity (Fletcher et al, J Immunol 1980, 124:158%1588; Gardner et al, J Immunof 1986, 136:140&1405). This alteration of receptor number and afhmity in phorbol ester-treated neutrophils leads to a loss of chemotactic responsiveness (Lad et al., FEBS L&t 1986,200:91-96). More recently, the motile response of normal dermal fibroblasts to soluble fibronectin was shown to be inhibited by treatment with TPA [ 181. Together, these studies demonstrate that procedures resulting in reduced chemotactic receptor a.%ity lead to reduced chemotactic responsiveness. Receptor afhnity appears to be modulated by membrane-bound protein kinase C, although the direction and magnitude of the response depends on the ceU type under study.

Signal transduction events EC&stimulated motility

underlying

Recent studies on the signal transduction mechanisms that govern matrix-induced ceU motility have centred on the role of membrane-associated GTP-binding proteins (G-proteins) and ion channels. From these studies, evidence has emerged that the haptotactic and chemotactic responses of some tumor cells may be distinguishable on the basis of their underlying signal transduction events. Lester et al. [l9] have used pettussis toxin to assess the role of G-proteins in melanoma ceU motility. Per-

853

854

Cell-to-cell

contact

able 2. Receptors

CM

molecule

and the extracellular

that

mediate

motility

matrix

in response

Receptor

to extracellular

c&p1

integrin

Various Transformed Normal

aminin

a6bl

integrin

Various tumor cells f5.141 Transformed fibroblastsfs1 Neurite outgrowth7

Iollagen

lastin

‘itronectin

tumor cellsf5f fibroblasts’fsf fibroblasts’

67 kD lamininbinding protein

A2058 melanoma cellst Neurite outgrowth”

b-1,4-galactosyltransferase

Neural crest cell7 Neurite outgrowthfrs~l6

a2j31

integrin

Various Transformed

59 kD VGVAPGbinding protein

M27

67 kD elastinbinding protein

A2058

avp3

integrin

HT-1080

RGD?

Unknown

YIGSRB LGTIPCf”

1

N-linked oligosaccharidens,rsL

tumor cellsL5f fibroblastsfsf

tumor

tumor

tumor

assay

Agarose drop assay fhaptotaxis) Boyden chamber chemotaxis Agarose drop fhaptotaxis) Neurite outgrowth

assay assay

Boyden chamber haptotaxis Neurite outgrowth assay Explant migration fhaptotaxis) Neurite outgrowth assay Migration Invasion

VCVAPG

Boyden

chamber

chemotaxis

cellstt171

VGVAPGttf’f LGTIPG671

Boyden

chamber

chemotaxis

cellsfsl

RGD%%

Agarose drop fhaptotaxis)

assay

cells**I1ll

tussis toxin catalyzes the ADP-ribosylation of certain Gprotein targets, including Gil, Gi2, G,, and Go, and thereby prevents the interaction of these G-proteins with the cell-surface receptors whose actions they mediate (for a review see Gilman, Annu Rev Biocbem 1987, High (B15FlOC23)

Type of motility

Unknown

he single-letter amino-acid code is used here. ‘Albini et al., / Cell Biol 05:2347-2358; %Wewor et al., Cancer Res 1987, 47:5691-5698; §Graf et /at/ Acad Sci USA 1988, 85:1282-1286; TRunyan et a/., / Cell Biol 1986, tMecham et a/., Biochem 1989, 28:3716-3722; %%Pytela et a/., Proc Nat/

56:615-649).

(ECM).

Recognition site

Cell type

lbronectin

fpe IV

matrix

and low (B15FlC29)

metastatic Bl6 melanoma cell lines exhibit high and low motility, respectively, in response to soluble gradients of fibronectin, laminin, and collagen type IV. Pertussis toxin treatment inhibited both random and directed motility of the highly metastatic cell line but had no effect on the poorly metastatic ceU line. CeU adhesion was not affected by treatment of either ceU type with pertussis toxin. Immunoblotting studies revealed that the Gi2 pertussis toxin-sensitive G-protein is more abundant in the highly metastatic cells, implying that the greater motility and invasiveness of this clone may be mediated by a signal transduction pathway involving this G-protein [ 191. The effects of pertussis toxin on ECM-mediated motility have also revealed interesting differences in the mechanisms underlying the haptotactic and chemotactic re-

through collagen gels through matrigel-coated filters

1987, 105:1867-1872; tTomaselli et a/., / Cell Biol 1987, al., Biochemistry 1987, 26:6896-6900; //Kleinman et al., Proc 102:432-441; “Blood et a/., / Cell 8iol 1988, 107:1987-1993; Acad Sci USA 1985, 87668770.

sponses of A2058 melanoma cells [ 11. A2058 melanoma cells exhibit both chemotactic and haptotactic responses to laminin, fibronectin and type IV collagen. These responses were measured using the Boyden chamber as say protocols described previously. Chemotaxis to collagen type IV or laminin but not to fibronectin was completely or partially blocked by treatment with pertussis toxin, whereas haptotaxis to all three matrix proteins was completely insensitive to the toxin [ 11. CeU adhesion to coated and uncoated filters was apparently untiected by pertussis toxin. These findings suggest that different signalling systems mediate chemotaxis and haptotaxis and raise the question of whether different receptors are involved in the chemotactic and haptotactic responses to ECM proteins. The findings of Taraboletti and colleagues (I Cell Biof 1987, 105:240%2415) suggest that this may be the case for thrombospondin because, as described previously, the chemotactic and haptotactic responses to thrombospondin are mediated by domains on opposite ends of the protein.

Cell motilitv

The role of cholera toxin-sensitive G-proteins in ECMstimulated motile responses remains ambiguous. Cholera toxin catalyzes the ADP-ribosylation of G,, the G-protein that couples receptors to adenylate cyclase, resulting in persistent adenylate cyclase activation (Gilman, 1987). Cholera toxin treatment results in decreased motility and invasion by both high and low metastatic Bl6 sublines [ 191, whereas the motile responses of A2058 cells are unalfected by cholera toxin or by 8-bromo-cAMP treatment [l] , demonstrating that CAMP is not involved in the signal transduction pathways underlying ECM-stimulated motility in all cells. New evidence has revealed a potentially important role for ion fluxes in modulating cell motility. Adelmann-Grill et al. [ 181 have demonstrated that amiloride-sensitive sodium/proton exchange is required for the chemotactic response of normal dermal iibroblasts to the cell-binding fragment of iibronectin. Interestingly, amiloride has been shown to inhibit the chemotactic, but not the chemokinetic, response of neutrophils to formyl peptide (Simchow&, J Biol Cbem 1985, 260:1324%13253). In addition, Jacob and coworkers (Proc Nat1 Acud Sci USA1987, 84:995-999) have reported that elastin peptides stimulate calcium and sodium influx and inhibit calcium efflux in monocytes, suggesting that these ion channel events may have a role in the motile response of cells to elastin peptides.

Annotated reading 0 00

A major goal for this field, therefore, is to develop and use assays that will allow a clear distinction to be made between ECM-stimulated chemokinesis, chemotaxis, and haptotaxis. In particular, it would be useful to measure chemokinetic and/or chemotactic responses in the absence of haptotactic stimulation. As progress is made in experimentally separating these motile responses, we will

Zetter and Brirrhtman

references

Of interest Of outstanding

and recommended

interest

1. 00

Aztwoo~l~~ S, STRACKE Ml, KRUIZCH H, SCHIFFMANN E, LIOITA IA: Signal transduction for chemotaxis and haptotaxis by matrix molecules in tumor cells. / Celf Biol 1990, 110:1427-1438 Pet-tusk toxin treatment inhibited chemotaxis but not haptotaxis of A2058 melanoma cells to collagen type IV and laminin but had no effect on either chemotaxjs or haptotaxis to fibronectin. Cholera toxin treatment had no effect on the migratoty response of these cells to arty of the three matrix proteins. 2.

0

CHELBERC MK, TSUIBARI’ EC, ?iAUSER & McCm IV collagen-mediated melanoma cell adhesion

tion: involvement lagen molecule.

JB: lypc and migra of the col-

of multiple, distinct domains Cancer Res 1989, 494796-4802.

K1735 M4 melanoma cells exhibited dose-dependent adhesion, spreading and migration to type IV collagen and to the triple helical domain (p-Iv) of type N collagen. The evidence presented suggests that the motile response of M4 cells to type N collagen is pdmarily haptotactic in nature.

.a

It is likely that distinct signalling systems control the separate components of cell motility. One set of signals may prompt a ceU to change from a stationary to a moving state, another set may instruct the ceU to orient in a gradi ent of soluble chemoattractant, and yet another may mediate orientation along a haptotactic gradient of an adhesive matrix molecule. Because chemotaxis across a membrane titer requires adhesion to the filter, ceU locomotion, and ceU orientation toward a gradient, disruption of any one of these processes will result in reduced chemotaxis. A given motile response should be broken down to ascertain whether a stimulator or inhibitor is acting directly on one or more of these parameters. For the matrix molecules discussed in this review, the clearest evidence supports the notion that most of them operate as haptotactic agents that mediate ceU motility by providing an adhesive orientation. In a few cases, defined matrix peptides or fragments such as VGVAPG or the heparin-binding amino-terminal domain of thrombospondin clearly orient cells in a soluble gradient and therefore induce true chemotaxis.

matrix

be better equipped to uncover the particular receptors and transduction mechanisms that control these separate events.

3.

Conclusion

and the extracellular

BRANDLF( BK, S~HNAAR RL Tumor ceU haptotaxis on covalently immobilized linear and exponential gradients of a ceU adhesion peptide. Deu Biol 1989, 135:74-86.

A novel assay for haptotaxis is described in which polyacrylamide surfaces are covalently derivatized with a gradient of RGD peptide. B16FlO cells uniformly seeded on these gradient gels accumulated over time at a position corresponding to higher RGD-peptide densities, whereas cells seeded on control non-gradient gels did not redistribute. 4.

a

PEWS R, P~ulssolu M. BRONNER FM: Molecular mechanisms of avian neural crest cell migration on fibronectin and laminin. Derj Biol 1989. 1.36~222-238.

The domains of tibronectin and laminin that mediate neural crest ceU migration were examined. The 105000 Mr cell-binding and the C-terminal heparin-binding domains of tibronectin, and the ES fragment of laminin supported migration. Migration on the 105 GO0 Mr cell~binding domain of fibronectin was inhibited by RGDS, whereas migration on the C-terminal heparin-binding domain was inhibited by hepatin. Migration on laminin was not inhibited by RGDS or by MGSR 5.

00

KM, KENNEDY DW, YAMADA SS, GRANCK WT, AKp(AhlA SK: Monoclonal antibody and synthetic inhibitors of human tumor cell migration. Cancer

YAMADA

H, CHEN peptide Res 1990,

50448-496. Monoclonal antibody studies suggest that bl integrins are involved in the migration of a variety of ceU lines on laminin, tibronectin and coUagen. In particular, the ~1501 and a2f31 integrins appear to be important in cell migration on fibronectin and collagen, respectively. DAVIS & OGLE RC, m CD: Embryonic heart mesenchymal ceU migration in laminin. Deu Biol 1989. 133:37-53. taminin and collagen I are shown to be good substrates for embryonic heart mesenchymal ceU migration. The laminin peptide motif YlGSR inhibited cardiac mesenchymal ceU migration on laminin but not on collagen 1.

6.

0

7. 0

MECHAM

RP, HINEK

elastin receptor to the 67-kDa

A, GRIFFIN

shows tumor

1989, 26416652-16657. Fetal calf ligament tibroblasts the elastin peptide VGVAPG,

CL, SENIOR RM, LIOITA u\: The similarities

structural and functional ceU laminin receptor.

J Biol

and A2058 rumor cells migrated and the laminin peptide LGTIPG

&em

to elastin. with sim-

855

856

Cell-to-cell

contact

and the extracellular

matrix

Uar dose-response proliles. Chemotaxis to the lamipin peptide and to elastin were inhibited by the presence of 100 mM lactose. The authors speculate that migration to the elastin and laminin peptides may be mediated by the same receptor. 8.

TASHIRO

K,

SEPHEL GC,

WEEKS

B,

SAW

M,

MARTIN

GR,

KLEUMANHK, YAMADA Y: A synthetic peptide containing the IKVAV sequence from the A chain of laminin mediates cell attachment, migration, and neurite outgrowth / Biol &em 1989, 264:16174-16182. PA22-2, a 19.mer peptide derived from the E8 fragment of the laminin A chain, promoted adhesion, spreading, and migmtion of several cell types as well as neurite outgrowth of PC12 cells. The active site for adhesion and neurite outgrowth within PA22.2 was defined as the pentapeptide IKVAV. l

M, b3l7.Ky JC, KOPP F, MARTIN PM: Laminininduced capping and receptor expression at cell surface in a rat rhabdomyosarcoma cell line: involvement in ceU adhesion and migration on laminin substrates. &!I Cell Res 1989, 185:482485. Immobilized laminin stimulated the migration of rat rhabdomyosarcoma cells. Capping of laminin receptors on these cells and expression of new laminin binding sites wzs induced by soluble laminin.

9.

BOUZON

l

clonal antibody directed against the a5 subunit of the a5Pl fibronectin receptor had a stimulatory effect. 14. e

DEDH.ARS, SAUW~ERR: Alterations in integrin receptor expression on chemically transformed human cells: specilic enhancement of laminin and collagen receptor complexes. J Cell Biol 1990, 110:481489. When non-tumorigenic, non-invasive human osteo.sarcoma (HOS) cells were chemically transformed with N-methyl-N’-nitro-N-nitrosoguanidine (MNNG), they acquired a tumotigenic, in~sive phenotype. The increased imasiveness of the MNNG-HOS cells was associated with increased expression of the a6p1, a2/31, and alp1 integrins, and decreased expression.of the uvp3 integrin. Invasion of these cells through matrigel was inhibited by monoclonal antibody directed against the a6 subunit BEGOVACPC, SHURBD: CeU surface gaiactosyltransferase me15. * diates the initiation of neurite outgrowth from PC12 cells on laminin. J Cell Biol 1990, 110:461470. Inhibitors of GalTase activity including anti-GalTase IgG and a-lactalbumin inhibited neurite outgrowth of PC12 cells on laminin. These inhibiting reagents had a greater effect on initiation of neurite outgrowth than on elongation, and indirect immunofluorescence localized GalTase to the growth cones of developing neurites. ECKSTELNDJ, SHURBD: Laminin induces the stable expression of surface galactosyltransferase on lamellipodia of migrating cells. J Cell Biol 1989, 108:2507-2517. Anti-GalTase IgG and its Fab fragments inhibited mesenchymal cell migration on laminin- but not fibronecti-coated surfaces. The level of surface GalTase was elevated on the lamellipodia of cells migrating on laminin, whereas GalTase was not detectable on lamellipodia of cells migrating on Iibronectin. 16.

10.

CHELBERG MK, MCJB. TSILBARY EC: Characterization

SKUBI’IZ

APN,

FURCHT

LT,

of a synthetic peptide from Type IV collagen that promotes melanoma ceU adhesion, spreading, and motility. / Cell Biol 1990, 111:261-270. Synthetic peptides derived from the sequence of collagen type Iv were examined to see if they srimulated adhesion, spreading, and motility of cells. Peptide IV-HI (GVKGDKGNPGWFGAP) stimulated adhesion and spreading in some of the cells tested and was a potent chemoattractant for M4 melanoma cells. Prolyl residues within the peptide were necessary for these activities. l

11.

BUIOD CH, Z!ZIIXR BE Membrane-bound protein k&se C modulates receptor a&&y and chemotactic responsiveness of Lewis lung carcinoma sublines to an elastinderived pep tide. J Bid &em 1989, 264:10614-10620. For the Lewis lung carcinoma subline H59, the motile response to VGVAPG is dependent on VGVAPG receptor affinity, which in turn correlates with levels of membrane-associated protein kinase C. l

12.

O’SHEA KS, RHFLINHEMER JS, Dtxrr VM: Deposition and role of thrombospondin in the bistogenesis of the cerebellar cortex. J Cell Biol 1990, 110:127%1283. Thrombospondin was found to be associated with the leading edge of migrating granule cells in electron microscope studies of the developing cerebellar cortex. Antibodies against thrombospondin were shown to inhibit granule ceU migration in explant cultures. l

13.

hClYAhtA

SK, YAMADA

fi!?, CHEN

m,

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receptor function with monoclonal antibodies: roles in ceU adhesion, migration, matrix, assembly and cytoskeletal organization. J Cell Bid 1989. 109:863875. A monoclonal antibody directed against the Bl integrin subunit inhibited migration of WI-38 Iibroblasts on fibronectin. In contrast, a mono0

l e

17.

MECHAMRP, H~NEKA, ENIWI~TII R, WRENN DS, GIUFF~NGI SENIORRM: Elastin binds to a multifunctional 67 kD peripheral membrane protein. Biochemisfy 1989, 28:37163722. Three proteins of molecular weights 67 Ooo, 61 Ooo and 55 000 were iso lated from plasma membrane of elastin-producing cells by affinity chromatography on immobilized elastin peptides. The 67W1 Mr elastinbinding protein has properties of a galactoside lectin. l

18.

ADELMANN-GRIUBC, WACH F, BEHR J, Krtt~ti T: Involvement of protein kinase C in signal transduction during libroblast chemotaxis to platelet-derived growth factor and a fragment of fibronectin. Eur J CelI Biol 1989, 50:128-131. lnbibitors of phosphoinositide metabolism, protein kinase C, and sodium/proton antiport inhibited the chemotactic response of normal dermal libroblasts to the cell-binding fragment of fibronectin. l

19. l e

IISTER BR, MCJB, SUN ZQ, SMITH RS, FURCHT LT, SPIEGELAM: G-protein involvement in matrix-mediated motility and invasion of high and low experimental metastatic B16 melanoma clones. Cancer Res 1989, 49:594@5948.

Pertussis toxin treatment of a highly metastatic Bl6 ceU line resulted in decreased migration through mauigel and decreased chemotaxis to fibronectin, laminin, and collagen type IV. Immunoblotting SNdieS revealed that the highly metastatic ceU line had increased levels of Giz compared with a low metastatic. poorly motile B16 ceU line.