Differential expression of tenascin-C splicing domains in urothelial carcinomas of the urinary bladder

Biology of Tenascin C and its Role in Physiology and Pathology

Tenascin-C (TNC) is a multimodular extracellular matrix (ECM) protein hexameric with several molecular forms (180-250 kDa) produced by alternative splicing at the pre-mRNA level and protein modifications. The molecular phylogeny indicates that the amino acid sequence of TNC is a well-conserved protein among vertebrates. TNC has binding partners, including fibronectin, collagen, fibrillin-2, periostin, proteoglycans, and pathogens. Various transcription factors and intracellular regulators tightly regulate TNC expression. TNC plays an essential role in cell proliferation and migration. Unlike embryonic tissues, TNC protein is distributed over a few tissues in adults. However, higher TNC expression is observed in inflammation, wound healing, cancer, and other pathological conditions. It is widely expressed in a variety of human malignancies and is recognized as a pivotal factor in cancer progression and metastasis. Moreover, TNC increases both pro-and anti-inflammatory signaling pathways. It has been identified as an essential factor in tissue injuries such as damaged skeletal muscle, heart disease, and kidney fibrosis. This multimodular hexameric glycoprotein modulates both innate and adaptive immune responses regulating the expression of numerous cytokines. Moreover, TNC is an important regulatory molecule that affects the onset and progression of neuronal disorders through many signaling pathways. We provide a comprehensive overview of the structural and expression properties of TNC and its potential functions in physiological and pathological conditions.

Tenascin-C promotes bladder cancer progression and its action depends on syndecan-4 and involves NF-κB signaling activation

Background

Bladder Cancer (BCa) is a severe genitourinary tract disease with an uncertain pathology. Increasing evidence indicates that the tumor microenvironment plays a decisive role with respect to cancer progression, and that this is driven by tumor cell interactions with stromal components. Tenascin-C (TN-C) is an important extracellular matrix (ECM) component, which has been reported to be involved in other types of cancer, such as breast cancer. The expression of TN-C in BCa tissue has been reported to be positively associated with the BCa pathological grade, yet the presence of urine TN-C is considered as an independent risk factor for BCa. However, the role of TN-C in BCa progression is still unknow. Thus, the object of the present investigation is to determine the role of TN-C in BCa progression and the involved mechanism.

Methods

In this study, expression of TN-C in BCa tissue of Chinese local people was determined by IHC. Patients corresponding to tumor specimens were flowed up by telephone call to get their prognostic data and analyzed by using SPSS 19.0 statistic package. In vitro mechanistic investigation was demonstrated by QT-qPCR, Western Blot, Plasmid transfection to establishment of high/low TN-C-expression stable cell line, Boyden Chamber Assay, BrdU incorporation, Wound Healing, laser scanning confocal microscopy (LSCM) and ELISA.

Results

TN-C expression in BCa tissue increases with tumor grade and is an independent risk factor for BCa patient. The in vitro investigation suggested that TN-C enhances BCa cell migration, invasion, proliferation and contributes to the elevated expression of EMT-related markers by activating NF-κB signaling, the mechanism of which involving in syndecan-4.

Conclusions

Expression of TN-C in BCa tissues of Chinese local people is increased according to tumor grade and is an independent risk factor. TN-C mediates BCa cell malignant behavior via syndecan-4 and NF-κB signaling. Although the mechanisms through which syndecan-4 is associated with the activation of NF-κB signaling are unclear, the data presented herein provide a foundation for future investigations into the role of TN-C in BCa progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09285-x.

The Functional Role of Extracellular Matrix Proteins in Cancer

The extracellular matrix (ECM) is highly dynamic as it is constantly deposited, remodeled and degraded to maintain tissue homeostasis. ECM is a major structural component of the tumor microenvironment, and cancer development and progression require its extensive reorganization. Cancerized ECM is biochemically different in its composition and is stiffer compared to normal ECM. The abnormal ECM affects cancer progression by directly promoting cell proliferation, survival, migration and differentiation. The restructured extracellular matrix and its degradation fragments (matrikines) also modulate the signaling cascades mediated by the interaction with cell-surface receptors, deregulate the stromal cell behavior and lead to emergence of an oncogenic microenvironment. Here, we summarize the current state of understanding how the composition and structure of ECM changes during cancer progression. We also describe the functional role of key proteins, especially tenascin C and fibronectin, and signaling molecules involved in the formation of the tumor microenvironment, as well as the signaling pathways that they activate in cancer cells.

Alternative splicing controls cell lineage-specific responses to endogenous innate immune triggers within the extracellular matrix

The identification of barely more than 20,000 human genes was amongst the most surprising outcomes of the human genome project. Alternative splicing provides an essential means of expanding the proteome, enabling a single gene to encode multiple, distinct isoforms by selective inclusion or exclusion of exons from mature mRNA. However, mis-regulation of this process is associated with most human diseases. Here, we examine the impact of post-transcriptional processing on extracellular matrix function, focusing on the complex alternative splicing patterns of tenascin-C, a molecule that can exist in as many as 500 different isoforms. We demonstrate that the pro-inflammatory activity of this endogenous innate immune trigger is controlled by inclusion or exclusion of a novel immunomodulatory site located within domains AD2AD1, identifying this as a mechanism that prevents unnecessary inflammation in healthy tissues but enables rapid immune cell mobilization and activation upon tissue damage, and defining how this goes awry in autoimmune disease.

Tenascin-C and integrins in cancer

Tenascin-C (TNC) is highly expressed in cancer tissues. Its cellular sources are cancer and stromal cells, including fibroblasts/myofibroblasts, and also vascular cells. TNC expressed in cancer tissues dominantly contains large splice variants. Deposition of the stroma promotes the epithelial-mesenchymal transition, proliferation, and migration of cancer cells. It also facilitates the formation of cancer stroma including desmoplasia and angiogenesis. Integrin receptors that mediate the signals of TNC have also been discussed.

Tenascin-C: Form versus function

Tenascin-C is a large, multimodular, extracellular matrix glycoprotein that exhibits a very restricted pattern of expression but an enormously diverse range of functions. Here, we discuss the importance of deciphering the expression pattern of, and effects mediated by, different forms of this molecule in order to fully understand tenascin-C biology. We focus on both post transcriptional and post translational events such as splicing, glycosylation, assembly into a 3D matrix and proteolytic cleavage, highlighting how these modifications are key to defining tenascin-C function.

Tenascin C in metastasis: A view from the invasive front

The extracellular matrix protein tenascin C (TNC) is a large glycoprotein expressed in connective tissues and stem cell niches. TNC over-expression is repeatedly observed in cancer, often at the invasive tumor front, and is associated with poor clinical outcome in several malignancies. The link between TNC expression and poor survival in cancer patients suggests a role for TNC in metastatic progression, which is responsible for the majority of cancer related deaths. Indeed, functional studies using mouse models are revealing new roles of TNC in cancer progression and underscore its important contribution to the development of metastasis. TNC has a pleiotropic role in advancing metastasis by promoting migratory and invasive cell behavior, angiogenesis and cancer cell viability under stress. TNC is an essential component of the metastatic niche and modulates stem cell signaling within the niche. This may be crucial for the fitness of disseminated cancer cells confronted with a foreign environment in secondary organs, that can exert a strong selective pressure on invading cells. TNC is a compelling example of how an extracellular matrix protein can provide a molecular context that is imperative to cancer cell fitness in metastasis.

Tenascin-C and integrins in cancer

Tenascin-C (TNC) is highly expressed in cancer tissues. Its cellular sources are cancer and stromal cells, including fibroblasts/myofibroblasts, and also vascular cells. TNC expressed in cancer tissues dominantly contains large splice variants. Deposition of the stroma promotes the epithelial-mesenchymal transition, proliferation, and migration of cancer cells. It also facilitates the formation of cancer stroma including desmoplasia and angiogenesis. Integrin receptors that mediate the signals of TNC have also been discussed.

Tenascin-C and carcinoma cell invasion in oral and urinary bladder cancer

Carcinoma invasion is a complex process regulated by genetic and epigenetic factors as well. A relevant supportive condition for cancer cell migration is the reorganization of the extracellular matrix (ECM), which is realized in an orchestrated multicellular manner including carcinoma cells and stromal fibroblasts. An important key player in the process of ECM reorganization is Tenascin-C (Tn-C). The molecule occurs as different isoforms generated by alternative splicing and de novo glycosylation. Large variants of Tn-C are abundantly re-expressed in the invasive front of many carcinoma types. A special role for initiating migration and accompanied epithelial to mesenchymal transition has been suggested. Here, we review the current knowledge concerning the tumor biological importance of Tn-C, the synthesis and alternative splicing during the invasive process in general, and give an overview on the impact of Tn-C in urothelial carcinoma of the urinary bladder (UBC) and oral squamous cell carcinoma (OSCC).

Urine tenascin‑C is an independent risk factor for bladder cancer patients

Urine biomarkers offer a non‑invasive method of detecting bladder cancer, monitoring disease progression and predicting disease recurrence and therapeutic treatment efficacy. Tenascin‑C (TN‑C), as a component of the extracellular matrix, is vital in the progression of bladder cancer. However, there is little to report with regard to urine TN‑C and its correlation with bladder cancer grade, stage, recurrence and prognosis. In the present study, 66 samples of voided urine from patients with bladder cancer and 42 samples from volunteers were obtained. The urine TN‑C concentration was determined using an ELISA assay. The correlation between the urine TN‑C concentration and the tumor grade, stage and time from bladder cancer diagnosis to recurrence was analyzed by a rank correlation analysis. Multivariate Cox proportional hazards regression was used for finding the main life‑threatening factors among age, gender, tumor grade, stage, relapse and the urine TN‑C concentration. At the end, the Kaplan‑Meier method was used to evaluate the survival rate affected by urine TN‑C as a single factor. The results indicated that the urine TN‑C concentration in the bladder cancer patients was higher compared with the healthy control volunteers (22.5 times higher). Among all the patients, urine TN‑C concentration had a positive correlation with the bladder cancer grade and stage, with correlation coefficients of 0.905 and 0.308, respectively; however, this correlation was negative between urine TN‑C concentration and the time from bladder cancer diagnosis to recurrence. Moreover, the multivariate Cox proportional hazards model analysis indicated that urine TN‑C, like tumor grade and recurrence, may be an independent risk factor for bladder cancer patient survival. However, it is noteworthy that inflammation may affect the concentration of urine TN‑C. The results of the present study indicate that urine TN‑C may be used as a biomarker for monitoring the recurrence of bladder cancer in patients and for predicting its prognosis. However, inflammation of the urinary tract should be excluded first.

Selection and characterization of tenascin C targeting peptide

Since tenascin C is a factor expressed highly in the tumor-associated matrix, it would be a desirable first step for targeting the tumor-specific microenvironment. In fact, a high level of tenascin C expression has been reported in most solid tumors, including lung cancer, colon cancer and glioblastoma. Therefore, the targeted binding of tenascin C in tumor stroma would inhibit tumor metastasis by modulating cancer cell growth and migration. We isolated a peptide that bound to tenascin C by phage display peptide library selection, and the selected peptide specifically recognized tenascin C protein in xenograft mouse tissue. We also observed exclusive staining of tenascin C by the selected peptide in tumor patient tissues. Moreover, the peptide reduced tenascin C-induced cell rounding and migration. We propose that the tenascin C targeting peptide may be useful as a specific anti-cancer diagnostic and therapeutic tool for most human solid tumors.

Differential vascular expression and regulation of oncofetal tenascin-C and fibronectin variants in renal cell carcinoma (RCC): implications for an individualized angiogenesis-related targeted drug delivery

The study was aimed at determining the vascular expression of oncofetal fibronectin (oncfFn) and tenascin-C (oncfTn-C) isoforms in renal cell carcinoma (RCC) and its metastases which are well-known targets for antibody-based pharmacodelivery. Furthermore, the influence of tumour cells on endothelial mRNA expression of these molecules was investigated. Evaluation of vascular ED-A(+) and ED-B(+) Fn as well as A1(+) and C(+) Tn-C was performed after immunofluorescence double and triple staining using human recombinant antibodies on clear cell, papillary and chromophobe primary RCC and metastases. The influence of hypoxic RCC-conditioned medium on oncfFn and oncfTn-C mRNA expression was examined in human umbilical vein endothelial cells (HUVEC) by real time RT-PCR. There are RCC subtype specific expression profiles of vascular oncfFn and oncfTn-C and corresponding patterns when comparing primary tumours and metastases. Within one tumour, there are different vessel populations with regard to the incorporation of oncfTn-C and oncfFn into the vessel wall. In vitro tumour-derived soluble mediators induce an up regulation of oncfTn-C and oncfFn mRNA in HUVEC which can be blocked by Avastin(®). Vascular expression of oncFn and oncTn-C variants depends on RCC subtype and may reflect an individual tumour stroma interaction or different stages of vessel development. Therefore, oncFn or oncTn-C variants can be suggested as molecular targets for individualized antibody based therapy strategies in RCC. Tumour-derived VEGF could be shown to regulate target expression.

Existence of tenascin-C isoforms in rat that contain the alternatively spliced AD1 domain are developmentally regulated during hippocampal development

Tenascin-C (TN-C) is a multimodular glycoprotein of the extracellular matrix which is important for the development of the nervous system and has a range of different functions which are mediated by the different protein domains present. TN-C contains eight constitutive fibronectin type III (FNIII) domains and a region of alternatively spliced FNIII domains. In the mouse and chick, six of these domains have been described and characterized, whereas in human there are nine of them. In this report, we show that seven alternatively spliced FNIII domains exist in rat and describe the differential expression pattern of the additional domain AD1 during embryonic and postnatal rat brain development. The AD1 domain of rat is homologous to the ones described in human and chick proteins but does not exist in mouse. Its expression can be located to the developing rat hippocampus and the lining of the lateral ventricle, regions where the TN-C protein may affect the behavior of stem and progenitor cells. During hippocampal development AD1 and the other alternatively spliced domains are differentially expressed as shown by RT-PCRs, immunocytochemistry and in situ hybridizations.

B domain containing Tenascin-C: a new urine marker for surveillance of patients with urothelial carcinoma of the urinary bladder?

BACKGROUND

ECM remodelling during tumorigenesis entails the re-occurrence of different Tn-C(L) splicing variants. In patients with urothelial carcinoma of the urinary bladder (UBC), B and C domain containing Tenascin-C (B(+) and C(+) Tn-C) urine levels were shown to be increased in case of muscle invasiveness. Thus, the present study was aimed at examining the ability of B(+) and C(+) Tn-C as potential urinary surveillance markers of UBC patients.

METHODS

Urine levels of B(+) and C(+) Tn-C were determined by ELISA in 35 UBC patients during a 2 year follow-up period after therapy and related to clinical diagnosis and histological stage in 4 defined groups representing typical courses of disease.

RESULTS

B(+) Tn-C levels showed significant differences between cases of tumour progression or regression. The urine levels of B(+) Tn-C could be used to discriminate between cases without tumour recurrence and such with tumour existence (cut-off value: 0.8 ng/ml) or between non-muscle invasive and muscle invasive tumour growth (cut-off value: 3.5 ng/ml).

CONCLUSIONS

Progression of UBC with time is accompanied by significant changes in urinary levels of B(+) Tn-C. Urinary B(+) Tn-C can therefore be suggested as a valuable urine surveillance marker in UBC follow-up care.

Expression of tenascin-C and its isoforms in the breast

Tenascin-C (TNC) is an extracellular matrix glycoprotein which is frequently up-regulated in a variety of pathological conditions including chronic inflammation and cancer. TNC has been implicated in the modulation of cell migration, proliferation, invasion and angiogenesis. Multiple isoforms of TNC can be generated through the alternative splicing of nine exons located in the fibronectin type III region of the molecule. The profile of isoforms expressed differs between cancers and normal breast, with the fully truncated TNC isoform being predominant in normal and benign tissues and higher molecular weight isoforms induced predominantly in cancer. The addition of extra domains within the fibronectin type III repeat domain greatly affects TNC function with multiple exon combinations available for splicing. Exons 14 and 16 are considered to be tumour-associated and have been shown to affect breast cell line invasion and growth in vitro to a greater extent than the full-length TNC isoform. This mini review will provide a summary of the literature to date regarding the expression of TNC isoforms in the breast and also discuss more recent developments in the field regarding exon AD1.

Innovative proteomics for the discovery of systemically accessible cancer biomarkers suitable for imaging and targeted therapies

The discovery of biomarkers that are readily accessible through the circulating blood and are selectively overexpressed in pathological tissues has become a major research objective, particularly in the field of oncology. Indisputably, this group of molecules has a high potential to serve as an innovative tool for effective imaging and targeted cancer therapy approaches. In this attractive therapeutic concept, specific cancer proteins are reached by intravenously administered ligands that are coupled to cytotoxic drugs. Such compounds are able to induce cancer destruction while sparing normal tissues. Owing to the performance of mass spectrometry technology, current high-throughput proteomic analysis allows for the identification of a high number of proteins that are differentially expressed in the cancerous tissues. However, such approaches provide no information regarding the effective accessibility of the >biomarkers and, therefore, the possibility for these discovered proteins to be targeted. To bypass this major limitation, which clearly slows the discovery of such biomarkers, innovative methodological strategies have been developed to enrich the clinical specimens before the mass spectrometry analysis. The focus is laid on the group of proteins that are necessarily located either at the exterior face of the plasma membrane or in the extracellular matrix. The present review addresses the current technologies meant for the discovery and analysis of accessible antigens from clinically relevant samples.

A comparative analysis of oncofetal fibronectin and tenascin-C incorporation in tumour vessels using human recombinant SIP format antibodies

Tumour angioneogenesis is associated with the reexpression of oncofetal fibronectin (oncFn) and tenascin-C (oncTn-C) splice variants, which may serve as targets for antibody-based pharmacodelivery. Knowledge of the vascular distribution and organization in different tumours is of importance for the understanding of tumour vessel formation and might be crucial for therapy. Therefore, human SIP format antibodies against Fn ED-A, Fn ED-B and Tn-C A and C splice domains were used for immunofluorescence labelling in renal, lung, oral, colon, breast and urinary bladder carcinoma specimens and in a renal carcinoma xenograft. The spatial relation to stroma, vessels and vascular basement membrane (vBM) was analysed including CD31 and laminin alpha4 chain antibodies. Renal cell carcinomas and atypical carcinoid of the lung revealed vessel-restricted oncFn and/or oncTn-C depositions; all other entities showed a variable stroma positivity including vessels. The individual pattern of oncFn/oncTn-C incorporation in the vBM depended on tumour type, vessel size and intratumoural heterogeneity. There was a stratification of the vessel wall showing luminal oncFn and extraluminal oncTn-C depositions. As shown in the xenograft, perivascular oncTn-C is provided by carcinoma cells. In conclusion, tumours differ in the pattern of Fn or Tn-C isoform positivity in the vessel wall, potentially representing a tumour type specific endothelial cell-tumour cell-stromal cell interaction. Carcinoma cells themselves are involved in vascular Tn-C matrix organization. Up to antigen distribution, Fn and Tn-C domain antibodies may serve as vehicles for antiangiogenetic and antifibrotic agents; oncFn/oncTn-C based targeting should be adapted individually.

Stromal laminin chain distribution in normal, hyperplastic and malignant oral mucosa: relation to myofibroblast occurrence and vessel formation

BACKGROUND

The contribution of stromal laminin chain expression to malignant potential, tumour stroma reorganization and vessel formation in oral squamous cell carcinoma (OSCC) is not fully understood. Therefore, the expression of the laminin chains alpha2, alpha3, alpha4, alpha5 and gamma2 in the stromal compartment/vascular structures in OSCC was analysed.

METHODS

Frozen tissue of OSCC (9x G1, 24x G2, 8x G3) and normal (2x)/hyperplastic (11x) oral mucosa was subjected to laminin chain and alpha-smooth muscle actin (ASMA) immunohistochemistry. Results were correlated to tumour grade. The relation of laminin chain positive vessels to total vessel number was assessed by immunofluorescence double labelling with CD31.

RESULTS

Stromal laminin alpha2 chain significantly decreases and alpha3, alpha4, alpha5 and gamma2 chains and also ASMA significantly increase with rising grade. The amount of stromal alpha3, alpha4 and gamma2 chains significantly increased with rising ASMA positivity. There is a significant decrease in alpha3 chain positive vessels with neoplastic transformation.

CONCLUSIONS

Mediated by myofibroblasts, OSCC development is associated with a stromal up-regulation of laminin isoforms possibly contributing to a migration promoting microenvironment. A vascular basement membrane reorganization concerning alpha3 and gamma2 chain laminins during tumour angioneogenesis is suggested.

B and C domain containing tenascin-C: urinary markers for invasiveness of urothelial carcinoma of the urinary bladder?

PURPOSE

Surveillance of urothelial carcinoma of the urinary bladder (UBC) patients with respect to tumour recurrence and invasiveness is crucial for therapy and prognosis. Therefore, evaluation of non-invasive methods to monitor tumour progression is of high clinical interest. The study was aimed at investigating urinary concentrations of tenascin-C splicing domains for their value as tumour surveillance markers.

METHODS

Urinary concentration of B and C domain containing tenascin-C (Tn-C) was analysed by ELISA technology in 104 UBC patients, 11 patients with cystitis and 15 healthy donors as control. The investigation was supplemented by Tn-C immunohistochemistry and Western blotting.

RESULTS

A statistically significant increase in urinary concentrations of both Tn-C B and C domain with tumour progression could be evidenced. A concordant tumour-associated enhanced protein deposition in the carcinoma stroma could be demonstrated by immunohistochemistry in invasive UBC. Western blotting reveals proteolytic fragmentation of urinary Tn-C.

CONCLUSIONS

In summary, detection of Tn-C splicing domains in urine is suggested as a marker for the surveillance of UBC recurrence and invasiveness.

Antibody-mediated delivery of interleukin-2 to the stroma of breast cancer strongly enhances the potency of chemotherapy

PURPOSE

There is an interest in the discovery of biopharmaceuticals, which are well tolerated and which potentiate the action of anthracyclines and taxanes in breast cancer therapy.

EXPERIMENTAL DESIGN

We have produced a recombinant fusion protein, composed of the human antibody fragment scFv(F16) fused to human interleukin-2 (F16-IL2), and tested its therapeutic performance in the MDA-MB-231 xenograft model of human breast cancer. The F16 antibody is specific to the alternatively spliced A1 domain of tenascin-C, which is virtually undetectable in normal tissues but is strongly expressed in the neovasculature and stroma of breast cancer.

RESULTS

When used as monotherapy, F16-IL2 displayed a strikingly superior therapeutic benefit compared with unconjugated recombinant IL-2. The administration of doxorubicin either before (8 days, 24 h, or 2 h) or simultaneously with the injection of F16-IL2 did not decrease the accumulation of immunocytokine in the tumor as measured by quantitative biodistribution analysis. Therapy experiments, featuring five once per week coadministrations of 20 mug F16-IL2 and doxorubicin, showed a statistically significant reduction of tumor growth rate and prolongation of survival at a 4 mg/kg doxorubicin dose but not at a 1 mg/kg dose. By contrast, combination of F16-IL2 with paclitaxel (5 and 1 mg/kg) exhibited a significant therapeutic benefit compared with paclitaxel alone at both dose levels. F16-IL2, alone or in combination with doxorubicin, was well tolerated in cynomolgus monkeys at doses equivalent to the ones now used in clinical studies.

CONCLUSIONS

F16-IL2 may represent a new useful biopharmaceutical for the treatment of breast cancer.

The role of structural extracellular matrix proteins in urothelial bladder cancer (review)

The extracellular matrix (ECM) plays a key role in the modulation of cancer cell invasion. In urothelial carcinoma of the bladder (UC) the role of ECM proteins has been widely studied. The mechanisms, which are involved in the development of invasion, progression and generalization, are complex, depending on the interaction of ECM proteins with each other as well as with cancer cells. The following review will focus on the pathogenetic role and prognostic value of structural proteins, such as laminins, collagens, fibronectin (FN), tenascin (Tn-C) and thrombospondin 1 (TSP1) in UC. In addition, the role of integrins mediating the interaction of ECM molecules and cancer cells will be addressed, since integrin-mediated FN, Tn-C and TSP1 interactions seem to play an important role during tumor cell invasion and angiogenesis.

Role of Annexin-II in GI cancers: interaction with gastrins/progastrins

The role of the gastrin peptide hormones (G17, G34) and their precursors (progastrins, PG; gly-extended gastrin, G-gly), in gastrointestinal (GI) cancers has been extensively reviewed in recent years [W. Rengifo-Cam, P. Singh, Role of progastrins and gastrins and their receptors in GI and pancreatic cancers: targets for treatment, Curr. Pharm. Des. 10 (19) (2004) 2345-2358; M. Dufresne, C. Seva, D. Fourmy, Cholecystokinin and gastrin receptors, Physiol. Rev. 86 (3) (2006) 805-847; A. Ferrand, T.C. Wang, Gastrin and cancer: a review, Cancer Lett. 238 (1) (2006) 15-29]. A possible important role of progastrin peptides in colon carcinogenesis has become evident from experiments with transgenic mouse models [W. Rengifo-Cam, P. Singh, (2004); A. Ferrand, T.C. Wang, (2006)]. It is now known that growth stimulatory and co-carcinogenic effects of gastrin/PG peptides are mediated by both proliferative and anti-apoptotic effects of the peptides on target cells [H. Wu, G.N. Rao, B. Dai, P. Singh, Autocrine gastrins in colon cancer cells Up-regulate cytochrome c oxidase Vb and down-regulate efflux of cytochrome c and activation of caspase-3, J. Biol. Chem. 275 (42) (2000) 32491-32498; H. Wu, A. Owlia, P. Singh, Precursor peptide progastrin(1-80) reduces apoptosis of intestinal epithelial cells and upregulates cytochrome c oxidase Vb levels and synthesis of ATP, Am. J. Physiol. Gastrointest. Liver Physiol. 285 (6) (2003) G1097-G1110]. Several receptor subtypes have been described that mediate growth effects of gastrin peptides [W. Rengifo-Cam, P. Singh (2004); M. Dufresne, C. Seva, D. Fourmy, (2006)]. Recently, we identified Annexin II as a high affinity binding protein for gastrin/PG peptides [P. Singh, H. Wu, C. Clark, A. Owlia, Annexin II binds progastrin and gastrin-like peptides, and mediates growth factor effects of autocrine and exogenous gastrins on colon cancer and intestinal epithelial cells, Oncogene (2006), doi:10.1038/sj.onc.1209798]. Importantly, the expression of Annexin II was required for mediating growth stimulatory effects of gastrin and PG peptides on intestinal epithelial and colon cancer cells [P. Singh, H. Wu, C. Clark, A. Owlia, Annexin II binds progastrin and gastrin-like peptides, and mediates growth factor effects of autocrine and exogenous gastrins on colon cancer and intestinal epithelial cells, Oncogene (2006), doi:10.1038/sj.onc.1209798], suggesting that Annexin-II may represent the elusive novel receptor for gastrin/PG peptides. The importance of this finding in relation to the structure and function of Annexin-II, especially in GI cancers, is described below. Since this surprising finding represents a new front in our understanding of the mechanisms involved in mediating growth effects of gastrin/PG peptides in GI cancers, our current understanding of the role of Annexin-II in proliferation and metastasis of cancer cells is additionally reviewed.