Injection and incubation of circulating tumor cells from a cancer biopsy in zebrafish for accelerated prediction of cancer progression and response to treatment

Abstract

The present invention provides a method to rapidly screen tumor cells for invasive and metastatic characteristics, heterogeneity and their response to therapeutic agents, and provides a multi-well microinjection system for the automated imaging and microinjection of zebrafish embryos.

Claims

1. A method to establish tumors from circulating tumor cells (CTCs) obtained from biopsies for analysis of said CTCs comprising the steps of: (a) isolating one or more of said CTCs; (b) labeling the one or more CTCs with a cell tracking dye; (c) injecting the one or more CTCs into a 24 to 48 hours post fertilization (hpf) zebrafish embryo (embryo), having an embryo body and an embryo yolk sac; (d) incubating the embryo for 24 hours or more; (e) establishing one or more tumors in the embryo; and optionally repeating steps (c) trough (e) for multiple embryos.

2. The method of claim 1, wherein the cell tracking dye is a fluorescent dye.

3. The method of claim 1, wherein the one or more CTCs are injected into a 24 to 48 hpf zebrafish embryo yolk sac.

4. The method of claim 3, further comprising measuring a position of each of the one or more injected CTCs after incubating the embryo to determine whether the injected CTCs invade the embryo body or remain in the 24 to 48 hpf zebrafish embryo yolk sac.

5. The method of claim 4, further comprising using the position of at least one injected CTC to measure CTC metastatic potential, wherein if the at least one injected CTC invades the embryo body, the at least one injected CTC has metastatic potential.

6. The method of claim 4, wherein each position is measured by capturing one or more fluorescence images of the injected CTCs under a fluorescence microscope.

7. The method of claim 6, further comprising quantitating the injected CTCs in the 24 to 48 hpf zebrafish embryo yolk sac and the embryo body by one or more of: (a) using image analysis software to measure a width and a length of a CTC focus and calculate a volume of the CTC focus as (width)(length).sup.2, wherein each tumor comprises a CTC focus and contains at least one of the injected CTCs; (b) measuring an invasive index (II) of the CTC foci as II=1/n (number of CTC foci in the embryo at T hours/total number of CTCs injected in the embryo), where n is the number of embryos in the experiment, and T is the incubation time, and the greater the II, the higher the propensity of the injected CTCs to invade; and (c) measuring a migration index (MI) of the CTCs as MI=1/n (CD at T hours/total number of CTC foci at time T hours), where CD=Cumulative distance traveled by the injected CTCs, n is the number of embryos in the experiment, and T is the incubation time, where the higher the value of the MI, the more aggressively invasive are the injected CTCs.

8. The method of claim 7, further comprising determining whether any one of: the volume of the CTC focus; the II; or the MI are different in the presence versus the absence of a chemical.

9. The method of claim 1, wherein a first embryo incubation is with a chemical and a second embryo incubation is without the chemical, and the first embryo incubation is compared to the second embryo incubation.

10. The method of claim 9, further comprising measuring an effect of the chemical on the injected CTCs by: (a) digesting the first embryo and the second embryo in a protease solution after incubation to obtain injected CTCs; (b) dispersing the embryo and the injected CTCs with pipetting to dissociate them to one or more single cell suspensions; (c) fixing and counting the viable injected CTCs in the one or more single cell suspensions under a fluorescence microscope; (d) calculating a ratio of the viable injected CTCs to the injected CTCs; (g) comparing the ratio for incubation in the presence of the chemical to the ratio for incubation in the absence of the chemical; and (f) using the comparison to determine whether the chemical affects the injected CTCs.

11. The method of claim 9, further comprising measuring and comparing a pattern of invasiveness of the injected CTCs in the presence or absence of the chemical.

12. The method of claim 1, further comprising assessing changes in CTC DNA by: (a) enzymatically digesting the embryo and the injected CTCs after incubation; (b) isolating DNA from the digested embryo and the injected CTC; (c) PCR amplifying one or more genes from a first aliquot of the isolated DNA; (d) sequencing the PCR amplified one or more genes; and (e) bisulfite sequencing a second aliquot of the isolated DNA to locate one or more epigenetic modifications.

13. The method of claim 1, further comprising analyzing CTC gene expression by: (a) enzymatically digesting the embryo and the injected CTC after incubation; (b) isolating RNA from the digested embryo and the injected CTC; and (c) performing a Quantitative Real-Time PCR analysis of the CTC gene expression using two or more primers designed for one or more human genetic sequences.

14. The method of claim 1, further comprising analyzing a CTC protein expression by one or more of: (a) fixing the embryo using a chemical fixative; (b) using immunohistochemistry with one or more human protein antibodies to visualize the CTC protein expression; (c) visualizing the CTC protein expression using immunohistochemistry on one or more histological section slides of the embryo after CTC injection and incubation; (d) visualizing the CTC protein expression using an ELISA (enzyme-linked immunosorption assay); and (e) visualizing the CTC protein expression using a Western blot.

15. The method of claim 1, wherein a pro-angiogenic factor is added into water containing the zebrafish embryo before, during or after the injection of the CTCs.

16. The method of claim 15, wherein the pro-angiogenic factor is angiopoietin.

17. The method of claim 1, further comprising: (a) capturing one or more fluorescence images of the injected CTCs under a fluorescence microscope using green and red fluorescence filters after incubating the embryo; (b) analyzing the one or more fluorescence images using an image analysis software to capture a position of each of one or more CTC foci in the one or more fluorescence images, wherein each tumor comprises a CTC focus and contains at least one of the injected CTCs; and (c) using the analysis of the one or more fluorescence images to calculate a homing index (HI) of the CTCs as: HI=1/n (total number of CTC foci in an organ at T hours/total number of CTC foci at time T hours), where n is the number of embryos considered in the experiment, and T is the incubation time T; wherein (i) the cell tracking dye has a red fluorescence and (ii) the CTCs are injected into a 24 to 48 hpf green fluorescent protein transgenic zebrafish embryo yolk.

18. The method of claim 17, further comprising observing an organ-homing pattern change of the injected CTCs in the absence versus the presence of a drug.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the accompanying drawings:

(2) FIG. 1: Differential response of invasive and non-invasive primary lung tumor cells to drugs.

(3) FIG. 1A: Tumor coordinates of 30 xenografts captured through imaging are represented graphically.

(4) FIG. 1B: Tumor coordinates of 28 xenografts treated with Paclitaxel.

(5) FIG. 1C: Tumor coordinates of 29 xenografts treated with Paclitaxel and Carboplatin. (D=No drug control, +P=Treated with Paclitaxel, C+P=Treated with Carboplatin and Paclitaxel)

(6) FIG. 1D: Calculated Migration Index of untreated and treated xenografts. (D=No drug control, +P=Treated with Paclitaxel, C+P=Treated with Carboplatin and Paclitaxel)

(7) FIG. 1E: Calculated Invasion Index of untreated and treated xenografts. (D=No drug control, +P=Treated with Paclitaxel, C+P=Treated with Carboplatin and Paclitaxel)

(8) FIG. 1F: Brain metastatic tumors were observed in the xenografts, recapitulating the organ-homing observed in the patient.

(9) FIG. 1G: Drug response of the brain metastasis tumors in xenografts. (D=No drug control, +P=Treated with Paclitaxel, C+P=Treated with Carboplatin and Paclitaxel.

(10) FIG. 1H: Drug response of invasive and non-invasive cells in xenografts treated with Paclitaxel. Drug response was measured through expressions of MGMTs, 9 for survival and 9 for death.

(11) FIG. 1I: Drug response of invasive and non-invasive cells in xenografts treated with Paclitaxel and Carboplatin.

(12) FIG. 2 is a top plan view of the multi-well plate assembly component of one aspect of this invention;

(13) FIG. 3 is a top plan view of one of the removable modules of the embodiment of FIG. 2;

(14) FIG. 4 is a cross section showing the embryos handling wells, with a groove plate sitting within the holding frame of the embodiment of FIG. 2;

(15) FIG. 5 is enlarged cross sections of the embryo handling wells and the removable insert of the embodiment of FIG. 2;

(16) FIG. 6A is a horizontal cross-section view of a 48 hpf zebrafish embryo, and FIG. 6B is a transverse cross-section view of a 48 hpf zebrafish embryo.

(17) FIG. 7 is a schematic side view of the arrangement of a 48 hpf zebrafish embryo in the groove plate with an injection cover plate and a micropipette for microinjection of the embodiment of FIG. 2;

(18) FIG. 8 is a schematic side view of a rotatable micropipette for microinjection of the embodiment of FIG. 2;

(19) FIG. 9 is a schematic side view of a 48 hpf zebrafish embryo in a groove plate with an injection cover plate as a guide for the micropipette for microinjection of a tumor into a 48 hpf zebrafish embryo according to an embodiment of this invention;

(20) FIG. 10 is a schematic side view of a 48 hpf zebrafish embryo in a groove plate showing the rotatable angle of the micropipette for microinjection while the embryo is in the groove plate according to an embodiment of this invention; and

(21) FIG. 11A and FIG. 11B are schematic side views of a 48 hpf zebrafish embryo in a groove plate showing the flexibility for rotation of the micropipette while still allowing access to the embryo in the groove plate for microinjection thereinto according to an embodiment of this invention.

DETAILED DESCRIPTION OF THE INVENTION

Introduction

(22) Molecular and genomic profiling of cancer cells has become the new trend in targeted therapy and oncology research. However, the relevance of molecular heterogeneity of the cancer cells and their constantly changing dynamic nature, the relevance of molecular signatures of the primary tumor as well invaded or metastasized tumor cells is limited. In this scenario, defined by limited efficacy of current chemotherapies to metastatic cancers, and the limited application of genomic profiling of cancer cells, we explored the possibility of creating representative and biologically relevant live 3D tumors out of tumor tissues (e.g., surgically removed primary tumor, biopsy, CTCs, etc.) to obtain clinically relevant physiological information about invasion and metastasis.

(23) For a successful individualized and targeted approach to cancer treatment, a rapid assay method that can predict a patient's tumor physiology (such as growth, invasive ability, metastatic organ-homing, etc.) and response to various anti-cancer treatments is required.

(24) An individualized and targeted treatment approach is however further complicated by the dynamic nature of all cancers. As a result every primary, invaded or metastasized tumor is made up of heterogeneous population of cells. Therefore a process of separating/fractionating the cancer cell pool into various physiological or molecular categories is important.

(25) The present invention provides assays and methods for the prediction of cancer progression and response to treatment. The method may use an advanced Cancer Progression and Response Matrix. Thus certain embodiments of the current invention may be used to facilitate the design of individualized and targeted therapies based on predictable tumor progression and responses to treatment.

Definitions

(26) As used herein, the following terminologies have meanings ascribed to them unless specified:

(27) Subject or Patient or Individual typically include humans but can also include other animals including but not limited to rodents, canines, felines, equines, ovines, bovines, porcines and primates.

(28) Tumor includes a mass of cells found in or on the body of a subject that have some form of physiological, histological, molecular and or structural abnormality.

(29) Cancer includes any member of a class of diseases that have abnormal cells which grow in an uncontrolled fashion. This includes all neoplastic conditions and all cancers whether characterized benign, invasive, localized, pre-metastatic, metastatic, post-metastatic, soft tissue or solid, including any stage or grade.

(30) Biology or Physiology typically includes morphology, physiology, anatomy, behavior, origin, and distribution.

(31) Pathophysiology all typically mean the disordered physiological processes associated with a condition. Particularly, cancer is a set of diseases that are driven by progressive genetic abnormalities that include chromosomal abnormalities, genetic mutations and epigenetic alterations. Particularly epigenetic alteration, which are functionally relevant modifications to the genome that does not involve a change in the nucleotide sequence, play a significant role in regulating the overall biology of cancer cells. Epigenetic alterations have been observed due to environmental exposures.

(32) Biopsy refers to the process of removing cells or tissue samples for diagnostic or prognostic evaluation. Any known biopsy technique can be applied to the methods and compositions of present invention. Representative biopsy techniques include but are not limited to excisional, incisional, needle, and surgical biopsies. The choice of the biopsy technique used depends on tissue type to be evaluated and the location, size and type of the tumor.

(33) Invasion refers to encroachment or intrusion. Particularly, invasive tumor cells are cells that are able to invade into surrounding tissues. Not all tumor cells have the ability to invade.

(34) Metastasis is the development of secondary malignant growths (Metastatic tumors) at a distance from a primary site of cancer. It is the spread of cancer cells from one organ or part of the body to another non-adjacent organ or part. Cancer cells first move into the circulatory system (intravasation) followed by positioning into a secondary site to create secondary tumors (extravasation).

(35) Circulating tumor cells or CTC are tumor cells that have undergone intravasation and are found in the circulation. Circulating extratumoral cells include, but are not limited to, circulating tumor cells, disseminated cancer cells, and cancer stem cells. Circulating tumor cells can be otentially obtained from any accessible biological fluid such as whole blood, sputum, bronchial lavage, urine, nipple aspirate, lymph, saliva, needle aspirate, etc.

(36) Organ-homing involves seeding of circulating tumor cells into organs of metastasis. Primary tumors tend to metastasize to specific distant target organs. For example, lung cancer tends to frequently metastasize to the brain. The process or organ selection is not a random process although the physiology behind organ-homing is not well understood.

(37) Signal transduction occurs when an extracellular signaling molecule activates a cell surface receptor (Signaling molecule or Signal transducer). In turn, this receptor alters intracellular molecules creating a response, which typically include ordered sequences of biochemical reactions

(38) Molecular genetic tumor markers or MGTMs have been identified based on the biological characterization of tumors, such as tumor development, growth, invasion and metastasis. Some examples include, but are not limited to, oncogenes (K-ras, erbB-1 (EGFR), erbB-2 (HER-2/neu), bcl-2, c-/N-/L-myc, c-kit), tumor suppressor genes (p53, RB, p16, p27, FHIT, RASSF1A), telomerase, invasion and metastasis markers (MMP, VEGF, COX-2), cell adhesion factors (E-Cadherin, beta-catherin), epithelial markers (cytokeratin, CEA), apoptosis markers (caspase-3, cleaved PARP), single nucleotide polymorphism (SNP), and anticancer drug susceptibility markers (MRP, LRP, MDR, beta-tubulin, ERCC1). Differential activation/deactivation of signaling pathways as well as changes in invasiveness and/or organ-homing of cells, in presence of anticancer drugs can aid in the selection of a suitable cancer therapy regimen at the proper dose for each patient. There could be a multitude of related application including prediction of how well chemotherapy is progressing for a given patient.

(39) Chemicals represents broadly all chemical compounds or substances that have been obtained crude, or have been purified from natural (available in nature through botanical or artificial sources (such as synthesized artificially in a laboratory).

(40) Synthesized or naturally occurring chemicals and biologicals include, but are not limited to, medicinal or therapeutic substances, non-medicinal substances, occurring in nature, artificially created, preparations made from living organisms (plant, animal, etc.), or extracted from non-living animal sources or minerals. These can include chemotherapeutic drugs, pharmaceutical formulations, Natural Health Products, powders, tea and extracts, serums, vaccines, antigens, antitoxins, etc.

(41) Immunomodulation is the adjustment of the immune responses, as in immunopotentiation (activation of the immune system), immunosuppression (suppression of the immune system), or induction of immunologic tolerance. Specifically, there is a complex dynamism between immune cells and malignant cells in the tumor microenvironment, which has there is in fact significant prognostic relevance as the immune system has both tumor promoting and inhibiting roles. Tumor infiltrating immune cells, and the chronic inflammation at the tumor site play a significant role in the growth, procession, invasion and metastatic disease. Immunomodulation can therefore impact greatly the progression of the disease. In the context of the current invention, immunomodulation therefore represents the adjustment of immune responses of the tumor infiltrating immune cells that came with the patient tumor cell mass, regulating the regulators of the immune systems (interleukins and interferons) and regulating the host immune system, specifically the zebrafish immune cells.

EXAMPLES OF THE INJECTION OF CIRCULATING TUMOR CELLS

Experiment 1: Injection of Breast Cancer Cell Line MDA-MB-231 in Zebrafish

(42) Zebrafish eggs were collected and incubated for 48 h at 36 degC in E3 medium (5 mM NaCl. 0.17 mM KCl. 0.33 mM CaCl2. 0.33 mM MgSO4. 0.1% methylene blue). The embryos were anesthetized with tricaine and decorionated using Dumont #5 forceps.

(43) MDA-MB-231 cells (metastatic breast cancer cells) were grown in D-MEM (high glucose), 10% fetal bovine serum (FBS), 0.1 mM MEM NonEssential Amino Acids (NEAA), 2 mM L-glutamine, 1% Pen-Strep and labelled using CM-DiI (Vibrant, Lifetech, 4 ng/ul final concentration, incubated 4 mM at 37 C. followed by 15 mM at 4 C.). 50 cells were injected into the yolk of one 48 hpf tricaine anesthetised zebrafish embryo. Images were taken 24 h post injection.

(44) RESULTS: After injection, the isolated CTCs were localized at the site of injection but were also visible throughout the tail of the zebrafish embryo and were capable of forming metastatic patterns in the zebrafish embryo.

Experiment 2: Developing Tumors in Zebrafish from Isolated CTCs from Blood

(45) CTCs were collected from 20 ml blood (EDTA-Ca as anti-coagulant) from a Stage 4 lung cancer patient who has metastasis in the brain and one control healthy individual. CTCs were collected by sequential positive (anti-EpCam BerP4 antibody, AbCaM) and negative (anti-CD45, AbCam) selections using antibody coated magnetic beads (Dynabeads, Lifetech) according to manufacturer's instructions. Two-capture-wash-release were performed for each step. The yield was about 110 cells from the metastasis patient but no cells were detectable from the healthy donor. The CTCs obtained were stained with DiO (Vibrant, Lifetech, 200 mM final concentration) for 20 min at 37 degC. Total of 100 stained CTC cells were injected into the yolk of one 48 hpf tricaine anesthetised zebrafish embryo. Images were obtained 24 h post injection. RESULTS: Isolated CTCs were capable of forming tumors and formed metastases in the brain tissues of the zebrafish larvae.

Experiment 3: Differential Response of Invasive and Non-Invasive Primary Lung Tumor Cells to Drugs

(46) Tumor tissues from late stage lung cancer patient that had shown metastasis to the brain was minced and incubated in Liberase DL (Roche) as per manufacturer's instructions. Lung cells were passed through a 70 micrometer cell strainer and resuspended in 2 ml RPMI 1640 before counting. Cell viability was confirmed by trypan blue exclusion. Cells are labeled with fluorescent tracking PKH-67 (Sigma) dye following the manufacturer's instructions and resuspended in PBS containing 25 mM glucose. 100 cells are injected into the yolk sac using NanojectII micromanipulator device. A group of embryos are injected with PBS+glucose only as control. The embryos are then incubated in TE water containing antibiotic/antimycotic solution and let to recover overnight in an incubator at 35 degC. After 24 h of incubation post tumor transplantation, embryos are imaged under a fluorescent microscope to ensure the presence of tumor cells in the yolk sac. Drugs/Treatments are added at various concentrations and the plate with embryos are incubated at 35 C. for an additional 3 days. Embryos were anesthetized with tricaine and re-imaged under a fluorescent microscope. Drugs used in this experiment were Paclitaxel alone or in combination with Carboplatin. Drug response was measured through expressions of 18 genes (BCL2, BCL-X, BCL-B, BFL-1, BCL-W, MCL1, CDC2, CYCLIN-D, CYCLIN-AL BAX, BAK, BOK, BID, BIM, BAD, BMF, NOXA, PUMA), nine (9) for survival (growth and cell cycle) and nine (9) for death (apoptosis).

(47) RESULTS: Tumor coordinates graphically represented (FIG. 1) show very high reproducibility of the invasion and metastasis patterns in the presence or absence of drug treatment. There is differential response of the invasive tumors in comparison to non-invasive tumor cells in presence of drugs as measured through Invasion Index, Migration Index as well as Homing Index. There is also a very clear difference in survival (measured by cell cycle and growth) and death (measured by apoptosis) of non-invasive and invasive cells.

Examples of the Use of the Microinjection Apparatus

(48) Description of FIGS. 2 to 5

(49) As seen in the FIGS. 2 to 5, the multi-well plate assembly component 10 of one aspect of this invention includes a holding frame 12 including a base plate 28 supporting a plurality of embryo handling wells 24. In this embodiment, the assembly 10 is made in a 96 well plate format and complies with international standards, although other standards may be used. This set-up can therefore be used with all standard microtiter plate readers and can be manipulated in all suitable liquid handlers. The multi-well plate assembly component 10 includes a lid 16, which is preferably provided with labels to mark the positions of wells of the multi-well plate assembly component 10, that offers safety, isolation, and prevents liquid in wells from drying.

(50) In this embodiment, eight separable, removable modules 18 (seen in detail in FIG. 3) are mounted in the holding frame 12. Every one of the eight separable, removable modules 18 has a groove plate 20 and a removable insert 22 that is mounted on the groove plate 20. As seen in FIG. 4, the groove plate 20 includes a plurality of the aforementioned embryo handling wells 24 and a lateral liquid handling well 26.

(51) Each embryo handling well 24 preferably has a cylindrical upper section 30 and a conical lower section 32. The lateral liquid handling well 26 is preferably completely cylindrical. The lateral liquid handling well 26 and the embryo handling wells 24 are interconnected at their outlet ends by a transverse drain channel 34. The removable insert 22 abuts the holding frame 12 at its outer edge and abuts the outer edges of the embryo handling wells 24 at its lower edge. The removable insert 22 can be removed for better manipulation of the embryo. The mounting of the removable insert 22 does not need to be airtight as there is the above-described intercommunication between each embryo handling well 24. The base plate 28 should preferably be transparent and UV penetrable. The removable insert 22 may be colored.

(52) In this embodiment as seen in FIGS. 2 to 4, there are 11 embryo handling wells 24 (W1-11) for housing embryos and one lateral liquid handling well 26. As previously described lateral liquid handling well 26 and the embryo handling wells 24 are interconnected at their outlet ends by a transverse drain channel 34. Therefore, any change in liquid level in one well (e.g. well W1) will result in compensation through other wells (e.g. wells W2 to W11). This will prevent uneven drying of wells and all wells will have the same liquid level. Therefore, all liquid handling, changing of media, etc. can be done by a robotic liquid handler in the liquid handling well 26, thereby substantially preventing handling, damage or stress to the embryos.

(53) All manipulations are done on the groove plate 20. As previously described, the embryo handling wells 24 have a conical bottom 32 where the larva of the zebrafish can be placed. As will be seen later in FIGS. 6A and 6B, given the shape of the zebrafish larva, once anesthetized, they will fall into the well conical lower portion 32 of embryo handling well 24 with the yolk on top. As will be seen in FIG. 7, a cover plate 36 can be positioned over the groove plate 20 in the place of the removable insert 22. As will be seen in FIG. 7, this cover plate 36 can act as the guide for the injection of the tumor cells along with pro-angiogenic factors into the embryo.

(54) The rectangle area within the broken lines in FIG. 4 is shown in enlarged form in FIG. 5.

(55) Description of FIGS. 6A and 6B

(56) FIG. 6A is a horizontal transverse cross-section of a 48 hpf zebrafish embryo, and FIG. 6B is a vertical transverse cross-section of a 48 hpf zebrafish embryo.

(57) Description of FIGS. 7 and 8

(58) As seen in FIG. 7, a micropipette unit 40 may have a replaceable micropipette, 42, preferably of glass. The 48 hpf zebrafish embryo 48 is disposed in the conical lower section 32 of the embryo handling well 24, with its dorsal side 50 within the lower narrower end of the conical section 32 and with its yolk 52 in the upper wider end of the conical section 32. The unit so provided is protected by the cover plate 36. The micropipette unit 40 is positioned to inject the tumor cells along with pro-angiogenic factors, preferably growth factor angiopoietin into the yolk 52 through the aperture in the cover plate 38.

(59) As seen in FIG. 8, the micropipette unit 40 having the replaceable micropipette 42 is controlled by a robotic arm 54. The liquid solution of the tumor cells along with a pro-angiogenic factor, preferably growth factor angiopoietin, is conducted through the robotic arm 52 via conduit 56. The robotic injector arm 54 can be rotated at any angle by means of control arm 58. The rotation is shown schematically by arrows 60.

(60) Description of FIGS. 9, 10 and 11

(61) FIG. 9 is a simplified replication of FIG. 7 showing the use of the cover plate 36 as a guide for the injection of the tumor along with a pro-angiogenic factor, preferably growth factor angiopoietin, into the yolk 52.

(62) As seen in FIG. 10, manipulations can be done under a microscope 62 without the removable insert in place. This allows manipulation of the embryo at any angle and injection can be performed to any part of the embryo body 50, 52.

(63) As seen in FIG. 11A, the micropipette unit 40 can be rotated from a vertical position shown in solid lines to a tilted position shown in broken lines so that injection can be performed to any part of the embryo body 50, 52.

(64) As seen in FIG. 11B, the micropipette unit 40 can be rotated from a tilted position shown in solid lines to a vertical position shown in broken lines so that injection can be performed to any part of the embryo body 50, 52. FIG. 8B also shows that the embryo body 50, 52 can also be rotated.

(65) Process of Operation

(66) Embryos are dechorionated at 48 hpf and moved to wells using a glass pipette. If desired, embryos can be treated with pro-angiogenic factor, preferably growth factor angiopoietin, to increase the likelihood and efficiency of tumor cell uptake. Media is removed partially through well 36 and tricaine is added to anesthetize the embryos. Tricaine solution can be added to each well 24 as well to speed up the process. The embryos undergo anesthesia and fall to the lower conical bottoms 32 of the embryo handling wells 24 of the groove plates 20. Given the conical shape 32 at the bottom of the embryo handling wells 24, and the yolk 52 being lighter than the rest of the body 50, larvae fall with yolk 52 facing upwardly. If required, injection cover plate 36 can be positioned to guide the tumor cell along with the pro-angiogenic factor, preferably growth factor angiopoitin. Robotic arm 54 fitted with the glass micropipette 40 is used to inject the tumor cells along with the pro-angiogenic factor, preferably growth factor angiopoietin, into the embryo yolk 50. The yolk sac seals itself rapidly.

(67) Once injections are complete, the injection cover plate 36 is removed and the removable insert 22 is positioned to create the wells 24.

(68) Pipetting out tricaine solution through well 26 can change the fluids in the wells 24, and fresh media is added again through well 26. The wells 24 for each row of 11 embryos will therefore be filled, and each embryo will revive from anesthesia. Once they revive, they are free to swim around in their own wells and not mix with neighbouring embryos. This allows keeping track of individual embryos. The entire assembled unit with the lid 16 on and with swimming zebrafish larvae inside, can be stacked one above another and stored in an incubator as for other microtiter plates.

(69) Since, preferably, the groove plate 20 is transparent, the larvae can be observed under UV in real time without needing to handle the larvae. If needed, larvae can be anesthetized for observations as mentioned earlier without handling them. Not only tumor growth can be measured using software, but also swimming behavior can be observed in real time. Such observations may alternatively be done manually or by using detection software.

(70) After carrying out the above described example experiments, if the larvae need to be euthanized and stained, all handling of the larvae and changing of liquids can be done in this plate. One of the most important steps in whole embryo staining is rocking and shaking of embryos in solution for proper mixing.

(71) This step is generally performed in Eppendorf tubes because the mixing is not good in most 96 well plates even on a shaker. By pipetting up and down in well 26 alone, all 11 embryos can be rocked and shaken on a single module. Similarly, using a programmed liquid handler, all such processes for the entire plate can be optimized.

(72) Once all staining is done, fluorescence as a measure of tumor mass can be calculated directly using a UV plate reader. This same equipment can be used for other injections, such as DNA, RNA, morpholinos as well.