Patent Description:
This invention was made with government support under Grant Nos. <NUM> U54 CA163167-<NUM> awarded by the National Institutes of Health. The government has certain rights in the invention.

The present invention relates to a L1CAM inhibitor for use in inhibiting progression of established metastatic disease in a subject who has received treatment for a primary cancer, wherein the L1CAM inhibitor is an antibody or antibody fragment or single chain antibody that specifically binds to L1CAM, or a nucleic acid, such as, a short hairpin, interfering, antisense, or ribozyme nucleic acid comprising a region of homology to an L1CAM mRNA, such as a nucleic acid having a size between about <NUM> and <NUM> or between about <NUM> and <NUM> or between about <NUM> and <NUM> nucleotides long, and capable of hybridizing to L1CAM under physiologic conditions, and wherein the L1CAM inhibitor is administered at least one month after a course of chemotherapy, targeted therapy, immunotherapy and/or radiotherapy of the primary cancer is completed.

In particular embodiments, said L1CAM inhibitor in a regimen that targets slow-growing metastatic cancer stem-like cells ("MetCSCs") as exist in post-chemotherapy residual disease.

Despite recent advances in cancer therapeutics, metastasis remains the main cause of cancer death. Chemotherapy and targeted therapies for metastatic disease may induce tumor responses, but are nearly always followed by resistance and lethal relapse. The residual disease that persists after therapy and drives regrowth has been proposed to contain metastatic cancer stem-like cells (MetCSCs) that are particularly capable of self-renewal, and that are slow cell-cycling, tumor re-initiating and therapy resistant (Oskarsson et al. , <NUM>; Hanahan et al. , <NUM>; Malladi et al. Targeting MetCSCs may offer an important approach for treating metastatic cancer and micrometastatic residual disease in the adjuvant setting.

L1CAM was originally identified as a neuronal adhesion molecule (Rathjen et al. , <NUM>; Maness and Schachner, <NUM>). L1CAM is a large, multidomain protein ectopically expressed at the invasion fronts of many solid tumors and universally associated with metastasis and poor prognosis (e.g., Altevogt et al. Metastatic lung and breast cancer single cells invading the brain use L1CAM to intimately stretch along blood vessels, in a process termed vascular co-option (Valiente et al. , <NUM>; <CIT>). RNAi-mediated L1CAM knockdown inhibits vascular co-option and prevents the outgrowth of brain macrometastases (<CIT>).

<CIT> relates to methods and compositions for determining whether a cancer patient is at increased risk for developing metastatic spread of the cancer and, if the patient is at increased risk, for treating the patient by antagonizing L1CAM, such that the risk of metastasis is reduced.

<CIT> relates to an antibody, siRNA, shRNA or an antisense oligonucleotide which recognizes an L1CAM protein on the surface of the gallbladder carcinoma cells and specifically binds to the gallbladder carcinoma tissue, and a pharmaceutical composition containing the same can inhibit the growth, infiltration and metastasis of gallbladder carcinoma.

<CIT> relates to the use of Ll interfering molecules, especially anti-Ll antibodies, in tumor treatment. In particular, <CIT> relates to the use of said Ll interfering molecules in sensitizing tumor cells for the treatment with chemotherapeutic drugs of with radiotherapy and to the combined administration of Ll interfering molecules with chemotherapeutic drugs or with radiotherapy.

It is based, at least in part, on the discovery that L1CAM is a marker of MetCSCs, and is expressed on these quiescent, very slowly dividing cells that can therefore escape standard chemotherapy and later re-initiate tumor growth. It is further based on the discovery that L1CAM-depletion inhibits the initiation of metastasis not only in the brain, but also in the lungs, liver and bone from breast, lung, colon and renal cancer xenografts, demonstrating the importance of L1CAM in the initiation of multi-organ metastasis. In particular, inducible L1CAM knockdown in advanced macrometastatic xenografts was observed to inhibit the progression of metastases, highlighting the clinical relevance of L1CAM inhibition in established metastatic disease. It is further based, in part, on the discovery that L1CAM inhibition inhibited the growth of chemoresistant lung cancer xenografts, supporting a distinct mechanism of action from cytotoxic agents, and that inhibition of L1CAM was observed to render chemoresistant tumor cells sensitive to chemotherapy.

The present invention provides a L1CAM inhibitor for use in inhibiting progression of established metastatic disease in a subject who has received treatment for a primary cancer, wherein the L1CAM inhibitor is an antibody or antibody fragment or single chain antibody that specifically binds to L1CAM, or a nucleic acid, such as, a short hairpin, interfering, antisense, or ribozyme nucleic acid comprising a region of homology to an L1CAM mRNA, such as a nucleic acid having a size between about <NUM> and <NUM> or between about <NUM> and <NUM> or between about <NUM> and <NUM> nucleotides long, and capable of hybridizing to L1CAM under physiologic conditions, and wherein the L1CAM inhibitor is administered at least one month after a course of chemotherapy, targeted therapy, immunotherapy and/or radiotherapy of the primary cancer is completed.

The L1CAM inhibitor is for administration at least one month after a course of chemotherapy, targeted therapy, and/or immunotherapy of the primary cancer has been completed. In certain non-limiting embodiments the L1CAM inhibitor is for administration at least one month after a course of a radiotherapy regimen of the primary cancer has been completed. In certain non-limiting embodiments the L1CAM inhibitor is for administration at least one month after a course of an complete (no cancer in the margins) surgical excision of the primary cancer has been completed. In certain non-limiting embodiments the L1CAM inhibitor is for administration in a maintenance regimen (e.g., administered at regular intervals (e.g., at least once a week, at least once a month, at least once every two months, at least once every three months, at least once every six months)) for a period of time after of the completion of chemotherapy, targeted therapy, and/or immunotherapy of the primary cancer. The period of time for maintenance therapy may be at least about three months or at least about <NUM> months or at least about one year or at least about <NUM> years. In certain non-limiting embodiments the L1CAM inhibitor is for administration after the subject has achieved remission of the primary cancer. In certain non-limiting embodiments the L1CAM inhibitor is for administration in a maintenance regimen (e.g., administered at regular intervals (e.g., at least once a week, at least once a month, at least once every two months, at least once every three months, at least once every six months)) for a period of time after achieving remission of the primary cancer. The period of time for maintenance therapy may be at least about three months or at least about <NUM> months or at least about one year or at least about <NUM> years.

A metastasis is a population of cancer cells at a location that is not physically contiguous with the original location of the cancer.

"Reducing the risk of metastatic spread" is relative to the risk of metastatic spread in a comparable control subject not treated with an L1CAM inhibitor.

"Inhibiting metastatic spread of a primary cancer" means one or more of: reducing the number, location(s), and/or size, of metastasis/es, and/or increasing the period of time to occurrence of metastasis/es, and/or prolonging survival, relative to a comparable control subject not treated with an L1CAM inhibitor.

"Inhibiting progression of metastatic disease" means one or more of the following: decreasing the size of existing metastasis/es, reducing the rate of growth of existing metastasis/es, reducing the incidence of newly detectable metastasis/es, improving quality of life, and/or increasing time to recurrence, and/or prolonging survival, relative to a comparable control subject not treated with an L1CAM inhibitor.

In various non-limiting embodiments, the subject is a human or a non-human animal, for example a dog, a cat, a horse, a rodent, a mouse, a rat, a hamster, a non-human primate, a rabbit, a sheep, a cow, a cetacean, etc..

In various non-limiting embodiments, the cancer is a breast cancer, a lung cancer, a renal cancer, a colorectal cancer, an ovarian cancer, a prostate cancer, a liver cancer, or a melanoma.

The site of metastasis may be, for example but not by way of limitation, brain, lung, bone, or liver.

In various non-limiting embodiments of the invention, the L1CAM inhibitor may be at least one month after a course of chemotherapy, targeted therapy, immunotherapy and/or radiotherapy of the primary cancer is completed and concurrently with a chemotherapy and/or targeted therapy and/or immunotherapy and/or radiotherapy regimen.

Said maintenance regimen may be followed whether or not active disease is determined to be present.

In various embodiments of the invention, a decision to use L1CAM inhibition as a treatment may be supported by determining that the metastasis to be treated expresses L1CAM and optionally one or more of EphB2, CD133 and/or CD44. Expression of L1CAM may be determined by any method known in the art, for example as discussed in the sections below. In certain non-limiting embodiments, expression of L1CAM may be detected using an antibody specific for L1CAM or amplification of L1CAM-encoding mRNA using polymerase chain reaction (PCR).

An L1CAM inhibitor is an agent that reduces the ability of L1CAM to co-opt blood vessels and /or reduces the ability of L1CAM to reinitiate or promote tumor growth or spread (e.g., the inhibitor reduces tumor cell invasiveness) and can be used to eliminate quiescent cells within tumors. An L1CAM inhibitor may act, for example and not by way of limitation, by reducing expression of L1CAM in the cancer cell or removing L1CAM from the cancer cell surface or binding to L1CAM such that its ability to bind to an endothelial cell or other cancer cells or normal tissue is reduced, for example by reducing the amount of L1CAM available for cell binding, by physical inhibition or by labeling L1CAM-expressing cells and thus marking them for destruction by the immune system.

In non-limiting embodiments, where the subject is a human, L1CAM to be inhibited is human L1CAM having an amino acid sequence as set forth in UniProtKB Accession No. P32004 and/or NCBI Accession Nos. NM_000425 version NM_000425. <NUM> and/or NM_001278116 version NM _001278116.

In non-limiting embodiments, the L1CAM inhibitor may be an an antibody or antibody fragment or single chain antibody that specifically binds to L1CAM. Non-limiting examples of such antibodies are disclosed in <CIT>, International Patent Application Publication No. <CIT>, and International Patent Application Publication No. <CIT>. In certain non-limiting embodiments an anti-L1CAM antibody or antibody fragment may be used to prepare a human, humanized, or otherwise chimeric antibody that is specific for L1CAM for use according to the invention. In certain non-limiting embodiments the L1CAM antibody, antibody fragment, or single chain antibody may inhibit binding of L1CAM to an endothelial cell or a blood capillary, to L1CAM or other molecules on neighboring cancer or stromal cells, or to other components of the extracellular matrix under physiologic conditions, for example in vitro or in vivo.

In non-limiting embodiments, the L1CAM inhibitor may be a nucleic acid, for example, a short hairpin, interfering, antisense, or ribozyme nucleic acid comprising a region of homology to an L1CAM mRNA. For example, such nucleic acids may be between about <NUM> and <NUM> or between about <NUM> and <NUM> or between about <NUM> and <NUM> nucleotides long, and be able to hybridize to L1CAM mRNA under physiologic conditions. A non-limiting example of a short hairpin (sh) RNA that inhibits L1CAM is set forth in the example below. In non-limiting embodiments, t L1CAM inhibitor which is a nucleic acid may be provided in a L1CAM-expressing cancer cell via a vector, for example a lentivirus, which may be selectively targeted to said cancer cell and/or wherein expression of the L1CAM inhibitor nucleic acid may be directed by a promoter which is selectively active in tumor cells. Non-limiting examples of nucleic acid sequence of an L1CAM mRNA include the sequence set forth in NCBI.

Accession Nos. NM_000425 version NM_000425. <NUM> and/or NM_001278116 version NM_001278116. In one specific non-limiting embodiment, the L1CAM inhibitor is RNAi TRCN0000063916 (The RNAi Consortium, Public TRC Portal), having a hairpin sequence
<IMG>
and a target sequence ACGGGCAACAACAGCAACTTT (SEQ ID NO:<NUM>); or the hairpin sequence
<IMG>
and a target sequence CCACTTGTTTAAGGAGAGGAT (SEQ ID NO:<NUM>); or the hairpin sequence
<IMG>
and a target sequence GCCAATGCCTACATCTACGTT (SEQ ID NO:<NUM>).

In certain non-limiting embodiments, the L1CAM inhibitor may be an antibody directed against a mutated L1CAM protein that is expressed on the surface of a MetCSC at high level. Non-limiting examples of mutated L1CAM proteins are set forth in Vos, Y. , and Hofstra, R. (<NUM>) and in <NPL>. An updated and upgraded L1CAM mutation database.

Metastasis is a highly inefficient process, in that primary tumor cells must first undergo epitheial-mesenchymal transition and escape from the primary tumor. After dissemination in the bloodstream, the vast majority of tumor cells die, leaving only a tiny fraction capable of surviving in a hostile foreign organ. These remaining few tumor cells may lie dormant for months or years, and then, when conditions are right, start to proliferate and reinitiate tumor growth. Once this so-called macrometastatic growth has been initiated, it is usually still possible to kill the bulk of tumor cells with chemotherapy, radiation, targeted therapy and/or immunotherapy - sometimes even to the point of no measurable disease - but a true cure is rarely possible.

This suggests that the tumor cells that form macrometastases - the MetCSCs - are resistant to chemotherapy, radiation, targeted therapy and/or immunotherapy, as they must survive these therapies applied to treat, first, the primary tumor and, later, its metastases. In addition, MetCSCs are able to undergo long-term self-renewal, have the ability to generate heterogeneous progeny (recapitulating tumor heterogeneity) and are capable of entering and exiting a dormant state, in which they can, potentially, exist for years (even decades, as seen in the case of ER/PR positive breast cancer).

Because chemotherapy may not be a treatment option for controlling metastatic growth, it is important to understand MetCSC mechanistically and identify therapeutic targets that will specifically kill these cells. To date, model systems for studying metastases have been imperfect.

L1CAM is a molecule associated with various cancers. Aberrant L1CAM expression has been demonstrated at the leading edge of primary tumors, and is associated with invasion, metastasis and poor prognosis in many human cancers including lung, breast and colon carcinomas (Voura et al. , <NUM>; Ben et al. , <NUM>; Tsutsumi et al. , <NUM>; Schroder et al, <NUM>; Tischler et al. , <NUM>; Boo et al. , <NUM>; Chen et al. , <NUM>; Fogel et al. , 2003a; Doberstein et al. , <NUM>; Fogel et al. , 2003b; Kim et al. , <NUM>; Maness et al. L1CAM expression is normally restricted to neurons where it mediates axonal guidance through interactions of the growth cone with surrounding components (Castellani et al. , <NUM>; Wiencken-Barger et al. A number of immunohistologic studies were performed to further study the expression of L1CAM during the metastatic process. L1CAM was found to be expressed at the primary tumor invasion front (<FIG>) where the cells remain quiescent (low Ki67; <FIG>). Strikingly, well-differentiated areas of tumors with intact glandular morphology expressed L1CAM predominantly in Ki67-low, quiescent cells; while in poorly-differentiated areas with loss of epithelial integrity, L1CAM expression could be observed in Ki67-high cells (<FIG>, <FIG>). L1CAM was not expressed in adjacent normal colonic epithelial cells (<FIG>). The expression of L1CAM is increased in tumor relative to normal tissue, and in metastasis relative to tumor (<FIG>, <FIG>). Finally, post-chemotherapy residual disease is strongly LCAM1+, and the cells are quiescent (low Ki67; <FIG>). All these features are consistent with L1CAM being a marker - and functionally relevant molecule - of MetCSCs. Experiments were performed to determine whether inhibition of L1CAM could impact metastasis. Cancer cells which either were transfected with shL1CAM (to knock down L1CAM expression) or control cancer cells were introduced into athymic mice (by intracardiac injection to assess brain or bone metastasis and by tail vein injection to assess lung metastasis) and the amount of metastases determined after several weeks using bioluminescence imaging. As shown in <FIG>, the extent of metastatic disease was dramatically reduced in mice that had received L1CAM-depleted cancer cells. L1CAM depletion (L1CAM inhibition) significantly reduced the progression of metastatic disease, including metastasis of breast cancer to lung (<FIG>), metastasis of breast cancer to bone (<FIG>), metastasis of colon cancer to liver (<FIG>), and metastasis of renal cell cancer to brain (<FIG>).

Experiments were also performed to determine whether L1CAM inhibition could be used to treat existing metastatic disease. In these experiments, expression of shL1CAM was placed under the control of an inducible promoter which could be activated by the drug doxycycline, so that knockdown of L1CAM could be turned on after dissemination of tumor cells had occurred. Athymic mice receiving either shL1CAMind -transfected cancer cells or control cancer cells were treated with doxycycline at day <NUM> and then assessed for metastatic disease by bioluminescence imaging at day <NUM> (<FIG>). The results are shown in <FIG> and <FIG>, which show that L1CAM knockdown inhibited the growth of established metastases and, in particular, metastasis of lung cancer to brain (<FIG>), metastasis of breast cancer to bone (<FIG>), and metastasis of breast cancer to lung (<FIG>). L1CAM has been determined to play a role in vascular co-option, but established metastases outgrow the need for vascular-co-option, making it interesting to observe that L1CAM inhibition also was able to inhibit progression of established metastases (<FIG>).

Experiments were performed to develop models for metastatic disease. In particular, patient-derived cells were used to generate organoids in culture, using a modification of the technique developed by Hans Clevers, in which organoids grow in three dimensions in matrigel and stem cell media enriched with Wnt is used for culturing (<FIG>). For example, metastatic tumor was harvested from a patient, dissociated into single cells, and then a L1CAM+, EpCAM+ fraction of cells was collected by fluorescence activated cell sorting (FACS) and used to establish organoid cultures (<FIG>). Of note, EphB2 med; L1CAM+ cells were found to constitute a novel subset of MetCSCs (<FIG>). When collected from a subject having colorectal cancer, the L1CAMhigh fraction was found to show increased cell surface expression of established colorectal cancer stem cell markers CD133, CD44 and EphB2 relative to L1CAMlow cells (<FIG>). Results of FACS analysis for markers L1CAM, EphB22, CD133, and CD44 are shown in <FIG> and <FIG>.

It was further observed that tumor L1CAM expression was associated with organoid-initiating capability (<FIG> and <FIG>). Residual tumors expressing high levels of cell-surface L1CAM could more frequently be cultured as organoids than tumors with low L1CAM levels (<FIG>). FACS sorted L1CAMhigh cells from freshly resected residual CRC liver metastases had greater organoid generating-capacity that L1CAMlow cells from the same tumors (<FIG>).

Interestingly, L1CAMhigh cells were found to give rise to both L1CAMhigh and L1CAMlow progeny (<FIG>). Further, L1CAM+ cells that are Ki67 low in vivo are more capable of organoid-initiation than L1CAM- cells (Ki67 high in vivo) (<FIG>), suggesting that L1CAM+ cells within patient tumors are slow-cycling reserve cells that can re-enter the cell cycle, reinitiate tumor growth and repopulate heterogenous tumors consisting of both L1CAM+ and L1CAM- cells under permissive conditions. This is demonstrated in <FIG>, which shows that nascent small organoids are comprised of universally L1CAM+ cells, but as the organoids grow, the cells divide to generate mostly L1CAM- differentiated progeny that populate the bulk of the organoid.

When L1CAM expression was compared between dissociated tumor and the organoids generated from the dissociated tumor, it was found that L1CAM expression was a trait selected for during organoid generation. The results from dissociated tumor collected from two different patients are shown in <FIG> and <FIG>. When L1CAM was deleted using CRISPR-Cas-<NUM>, fewer organoids resulted (<FIG>), suggesting that L1CAM is required for the survival and/or regrowth of organoid-initiating MetCSCs. Notably, dissociation of intact organoids into single cells markedly upregulated L1CAM expression (<FIG>).

Patient metastasis-derived organoids were expanded in vitro, FACS sorted into L1CAMhigh and L1CAMlow populations and implanted as subcutaneous xenografts into NSG mice, whereupon the L1CAMhigh cells displayed greater in vivo tumor re-initiation capacity (<FIG>). The subcutaneous tumors displayed well-differentiated glandular epithelial morphology and intestinal mucin secretion (<FIG>). FACS sorting of subcutaneous tumor-derived cells based on cell-surface L1CAM expression revealed that L1CAMhigh cells retained their organoid-reinitiating capacity (<FIG>).

Next, we injected Stage III CRC-derived organoids into the splenic vein of immunocompromised NSG mice. Liver metastases thus generated were then passaged as organoids and re-injected into the splenic vein. Such serially passaged liver metastatic organoids not only formed larger liver metastases more rapidly than their parental organoids, but also expressed higher levels of L1CAM (<FIG>). In sum, L1CAMhigh cells in therapy-resistant residual metastatic patient tumors are organoid and metastasis-reinitiating stem cells (MetSCs).

Kras-mutant lung cancer cells that were resistant to carboplatin and methotrexate were transfected with shCONTROL or shL1CAM operably linked to a doxycycline-inducible promoter. shCONTROL or shL1CAM containing cancer cells were then injected, intracardially, into athymic mice (day <NUM>). On day <NUM>, treatment with doxycycline and v=carboplatin or methotrexate was initiated, and tumors were assessed on day <NUM>. As shown in <FIG>, the cancer cells expressing L1CAM inhibitor were more sensitive to carboplatin or methotrexate than the control cells. This indicates that L1CAM inhibition can render chemoresistant cells more sensitive to chemotherapy.

To interrogate whether L1CAM is functionally required for organoid growth or regeneration, we performed CRISPR-Cas9 mediated knockout of L1CAM in metastasis-derived organoids (see <FIG>). L1CAM-knockout significantly inhibited the ability of organoid-derived single cells to regenerate new organoids (<FIG>). Similarly, doxycycline inducible knockdown of L1CAM inhibited organoid regeneration (<FIG>). Notably, withdrawal of doxycycline after <NUM> days of culture did not permit organoid regrowth, suggesting that L1CAM-deficient metastatic CRC progenitors require L1CAM not only to drive organoid regrowth but also to survive when detached from epithelial structures (<FIG>). Consistently, L1CAM-deficient cells displayed increased caspase activity in the first week following dissociation (<FIG>). Thus, L1CAM-deficient cells demonstrate detachment-induced, caspase-mediated cell death, a. L1CAM knockdown did not alter the expression of genes associated with pluripotency, ISC, wnt-response or differentiation. In vivo, L1CAM knockdown abrogated subcutaneous tumor growth in NSG mice (<FIG>). In sum, L1CAM does not drive the phenotypic progenitor cell identity of MetSCs, but is required for their survival and regrowth upon epithelial detachment, crucial requirements for successful tumor propagation and metastasis.

YAP activity is induced by loss of epithelial interaction and contact with stiff basement membrane in multiple contexts (<NPL>. Indeed, dissociation of organoids into single cells significantly induced expression of YAP target genes ANKRD1, CYR61 and ITGB1 (<FIG>).

Since L1CAM is required for survival, regrowth and restoration of tissue architecture by transformed epithelial cells, we wondered whether it might also be required in non-transformed epithelia when epithelial integrity is disrupted. As seen in the human, normal mouse colon epithelia did not express significant amounts on L1CAM (<FIG>). However, when grown as organoids, non-transformed colon epithelial cells induced L1CAM expression (<FIG>). As seen with cancer organoids, normal mouse colon organoids dynamically upregulated L1CAM immediately upon organoid dissociation, with total organoid L1CAM declining over time as the organoids grew larger (<FIG>). To test whether L1CAM is induced during epithelial injury in vivo, we treated C57BL6 with dextran sodium sulfate (DSS) water for <NUM> days. L1CAM was not expressed in control mice given water, but was expressed from day <NUM>-day <NUM> in regenerating colon crypts in areas that demonstrated DSS damage (<FIG>). L1CAM was expressed not in the crypt base compartment associated with rapidly proliferating stem cells, nor in the fully differentiated luminal cells, but instead in the regenerating transit-amplifying colon cells (<FIG>).

To interrogate the functional significance of L1CAM in colon regeneration, we crossed L1CAMfl/fl mice with the intestinal stem cell-specific Lgr5-GFP-IRES-Cre-ERT2 mice. Cre recombinase expression was induced by treating the mice with IP tamoxifen for three doses concurrent with DSS or water treatment. When given water, tamoxifen-treated mice displayed no alterations in weight (<FIG>), behavior or bowel habit. When treated with DSS, tamoxifen-treated Lgr5-GFP-IRES-Cre-ERT2/L1CAMfl/y demonstrated sustained weight loss and reduced survival in comparison to controls. Autopsy revealed significantly shortened colons, with histopathology showing diffuse inflammation with areas of mucosal denudation (<FIG>).

Next, we sought to understand how epithelial progenitor cells induce and regulate L1CAM expression. To determine whether colitis-associated inflammatory cytokines might contribute to L1CAM induction, we incubated human CRC organoids with conditioned media from normal or inflamed colons. Neither colitis conditioned-media nor incubation with recombinant cytokines associated with colitis or neuronal regeneration (where L1CAM has been previously implicated) induced L1CAM (<FIG>). In contrast, dissociation of organoids into single cells was necessary and sufficient for L1CAM upregulation (<FIG>). Structural integrity in intact epithelia is secured by e-cadherin homophilic cell-cell contacts in adherens junctions. We therefore hypothesized that loss of e-cadherin from the cell membrane in disrupted epithelia might induce L1CAM expression. Consistent with this hypothesis, shRNA-mediated knockdown of e-cadherin in CRC organoids induced L1CAM and YAP target gene expression (<FIG>).

Claim 1:
A L1CAM inhibitor for use in inhibiting progression of established metastatic disease in a subject who has received treatment for a primary cancer,
wherein the L1CAM inhibitor is an antibody or antibody fragment or single chain antibody that specifically binds to L1CAM, or a nucleic acid, such as, a short hairpin, interfering, antisense, or ribozyme nucleic acid comprising a region of homology to an L1CAM mRNA, such as a nucleic acid having a size between about <NUM> and <NUM> or between about <NUM> and <NUM> or between about <NUM> and <NUM> nucleotides long, and capable of hybridizing to L1CAM under physiologic conditions, and
wherein the L1CAM inhibitor is administered at least one month after a course of chemotherapy, targeted therapy, immunotherapy and/or radiotherapy of the primary cancer is completed.