Abstract 3091: Patient-derived organoid drug responses corroborate known target-drug interactions for selected anticancer agents

Patient-derived organoids (PDOrgs) are heterogeneous three-dimensional cellular clusters that have been shown to recapitulate the tumor histology and genetic alterations of their originating tissue. Numerous studies suggest the in vitro drug responses of tumor organoids align with in vivo responses. In this study, we evaluated fourteen anticancer agents against a cohort of PDOrgs from three disease histologies: colon, pancreatic, and non-small cell lung adenocarcinoma. The PDOrgs were obtained from the National Cancer Institute’s Patient-Derived Models Repository (https://pdmr.cancer.gov): a resource that offers clinically annotated and molecularly characterized models. The PDOrg models were selected for specific genetic variants of KRAS and BRAF, or different RNA levels of ABCB1, an ATP-dependent efflux pump. The approved and investigational agents were selected to target specific genetic variants and pathways: KRAS G12C covalent inhibitors (sotorasib and MRTX-1257), RAS pathway inhibitors (BAY-293, BI-3406 and TNO-155), BRAF V600E/K inhibitors (dabrafenib and encorafenib), ABCB1 substrates (paclitaxel, doxorubicin, 5-FU, AZD-1775, and SN-38), and ABCB1 non-substrates (gemcitabine and trametinib). The goal of the study was to assess whether the sensitivities of PDOrgs to therapeutic agents matched these genetic profiles under standard in vitro conditions. PDOrgs were seeded into 384-well microplates, in a semi-automated fashion, and exposed to nine concentrations of each anticancer agent for six days followed by cell viability assessment by CellTiter-Glo 3D. Data analysis was performed using GRmetrics, an R package for calculation and visualization of concentration-response metrics based on growth rate inhibition (https://git.bioconductor.org/packages/GRmetrics). These data demonstrated that PDOrgs harboring a KRAS G12C variant were uniquely sensitive to sotorasib and MRTX-1257 and were, overall, more sensitive to the other RAS pathway targeting agents. Conversely, PDOrgs harboring wild type RAS and other KRAS variants were largely unresponsive to these targeted agents. Likewise, only PDOrgs harboring the BRAF V600E variant were sensitive to dabrafenib and encorafenib. For the majority of PDOrgs, the pharmacological responses to agents that are ABCB1 substrates inversely correlated with ABCB1 RNA expression. This study demonstrates the ability of organoids to serve as useful models for evaluating therapeutic responses to anticancer agents, including identifying known target-drug associations. Moreover, the technical conditions, as well as the selected PDOrgs and therapeutic agents, may be used as a reference set for the validation of a fully automated PDOrg screening system. This project was funded in part with federal funds from the NCI, NIH, under contract no. HHSN261201500003I.

Citation Format: Curtis Hose, Erik Harris, John Connelly, Petreena S. Campbell, Mariaestela Ortiz, Eric Jones, Dianne Newton, Yvonne A. Evrard, Melinda Hollingshead, Ralph Parchment, Beverly A. Teicher, Nathan P. Coussens, James H. Doroshow, Annamaria Rapisarda. Patient-derived organoid drug responses corroborate known target-drug interactions for selected anticancer agents [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3091.

Putative tumor suppressor cytoglobin promotes aryl hydrocarbon receptor ligand-mediated triple negative breast cancer cell death

Nearly 40 000 women die annually from breast cancer in the United States. Clinically available targeted breast cancer therapy is largely ineffective in triple negative breast cancer (TNBC), characterized by tumors that lack expression of the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (Her2). TNBC is associated with a poor prognosis. Previous reports show that aryl hydrocarbon receptor (AhR) partial agonist 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F 203) selectively inhibits the growth of breast cancer cells, including those of the TNBC subtype. We previously demonstrated that 5F 203 induced the expression of putative tumor suppressor gene cytoglobin (CYGB) in breast cancer cells. In the current study, we determined that 5F 203 induces apoptosis and caspase-3 activation in MDA-MB-468 TNBC cells and in T47D ER+ PR + Her2 - breast cancer cells. We also show that caspases and CYGB promote 5F 203-mediated apoptosis in MDA-MB-468 cells. 5F 203 induced lysosomal membrane permeabilization (LMP) and cathepsin B release in MDA-MB-468 and T47D cells. In addition, silencing CYGB attenuated the ability of 5F 203 to induce caspase-3/-7 activation, proapoptotic gene expression, LMP, and cathepsin B release in MDA-MB-468 cells. Moreover, 5F 203 induced CYGB protein expression, proapoptotic protein expression, and caspase-3 cleavage in MDA-MB-468 cells and in MDA-MB-468 xenograft tumors grown orthotopically in athymic mice. These data provide a basis for the development of AhR ligands with the potential to restore CYGB expression as a novel strategy to treat TNBC.

AhR ligand aminoflavone suppresses α6-integrin-Src-Akt signaling to attenuate tamoxifen resistance in breast cancer cells

More than 40% of patients with luminal breast cancer treated with endocrine therapy agent tamoxifen demonstrate resistance. Emerging evidence suggests tumor initiating cells (TICs) and aberrant activation of Src and Akt signaling drive tamoxifen resistance and relapse. We previously demonstrated that aryl hydrocarbon receptor ligand aminoflavone (AF) inhibits the expression of TIC gene α6-integrin and disrupts mammospheres derived from tamoxifen-sensitive breast cancer cells. In the current study, we hypothesize that tamoxifen-resistant (TamR) cells exhibit higher levels of α6-integrin than tamoxifen-sensitive cells and that AF inhibits the growth of TamR cells by suppressing α6-integrin-Src-Akt signaling. In support of our hypothesis, TamR cells and associated mammospheres were found to exhibit elevated α6-integrin expression compared with their tamoxifen-sensitive counterparts. Furthermore, tumor sections from patients who relapsed on tamoxifen showed enhanced α6-integrin expression. Gene expression profiling from the TCGA database further revealed that basal-like breast cancer samples, known to be largely unresponsive to tamoxifen, demonstrated higher α6-integrin levels than luminal breast cancer samples. Importantly, AF reduced TamR cell viability and disrupted TamR mammospheres while concomitantly reducing α6-integrin messenger RNA and protein levels. In addition, AF and small interfering RNA against α6-integrin blocked tamoxifen-stimulated proliferation of TamR MCF-7 cells and further sensitized these cells to tamoxifen. Moreover, AF reduced Src and Akt signaling activation in TamR MCF-7 cells. Our findings suggest elevated α6-integrin expression is associated with tamoxifen resistance and AF suppresses α6-integrin-Src-Akt signaling activation to confer activity against TamR breast cancer.

Performance on the Wechsler Intelligence Scale for Children as related to salivary testosterone in children with learning disabilities: a poststudy analysis

Reanalysis of testosterone values published in 1993 gave a significantly higher mean and standard deviation for 15 learning-disabled children scoring P > V than those for 10 scoring V > P but not for a matched nonlearning-disabled group. Replication with larger samples would allow a test of hemispheric integration.

Salivary testosterone in children with and without learning disabilities

Previous studies have indicated that the sex steroids have organizational effects upon neural tissue and that abnormal secretion during development may lead to functional anomalies. In this study, we explore the possibility of prepubertal steroid hormone involvement in the etiology of learning disabilities. Salivary testosterone levels in 264 children without learning disabilities (133 males, 131 females) were measured and compared to that in 32 children with learning disabilities (25 males, 7 females). The presence of learning disabilities was significantly associated with higher salivary testosterone. Data from equivalent samples of learning-disabled and control subjects also were compared separately because of disparities in sample size and variable distribution in the total group analysis. A 32-member sample of nonlearning-disabled children was created by randomly selecting individuals who exactly matched the age, race, and sex characteristics of the learning-disabled group. The matched analysis further substantiated the association between testosterone secretion and learning disabilities. Thus, it is possible that some learning disabilities may be associated in part with abnormal testosterone levels.

Use of microgravity bioreactors for development of an in vitro rat salivary gland cell culture model

During development, salivary gland (SG) cells both secrete factors which modulate cellular behavior and express specific hormone receptors. Whether SG cell growth is modulated by an autocrine epidermal growth factor (EGF) receptor-mediated signal transduction pathway is not clearly understood. SG tissue is the synthesis site for functionally distinct products including growth factors, digestive enzymes, and homeostasis maintaining factors. Historically, SG cells have proven difficult to grow and may be only maintained as limited three-dimensional ductal-type structures in collagen gels or on reconstituted basement membrane gels. A novel approach to establishing primary rat SG cultures is use of microgravity bioreactors originally designed by NASA as low-shear culture systems for predicting cell growth and differentiation in the microgravity environment of space. These completely fluid-filled bioreactors, which are oriented horizontally and rotate, have proven advantageous for Earth-based culture of three-dimensional cell assemblies, tissue-like aggregates, and glandular structures. Use of microgravity bioreactors for establishing in vitro models to investigate steroid-mediated secretion of EGF by normal SG cells may also prove useful for the investigation of cancer and other salivary gland disorders. These microgravity bioreactors promise challenging opportunities for future applications in basic and applied cell research.

Preferential nuclear binding of estrogen in the formalin-fixed rat uterus

Rat uterus fixed overnight in buffered formalin retains the ability to specifically bind estradiol. However, the estrogen binding property of fixed tissue appears preferentially localized in the nuclear fraction regardless of hormonal status. Furthermore, the quantity of the nuclear estrogen receptor in fresh or fixed uterus is virtually identical in the presence or absence of estrogenic hormone. Yet, while both tissue preparations exhibit equivalent increases in the total nuclear receptor occupancy after hormone exposure, only the fresh uterus contains a major cytosolic estrogen binder which decreases in availability upon the estrogen-induced elevation of the nuclear bound steroid. However, the cytosolic estrogen receptor exhibits a significant loss in its ligand binding property after formalin exposure. Thus, the preferential localization of estrogen binding in the nuclear fraction of fixed whole tissue may just reflect that only the tightly bound nuclear estrogen receptor's functional and/or structural integrity survives long-term formation fixation. Our observation of estrogen binding in preserved tissue may also be a clinically useful tool in therapy analysis.

Differential distribution of an estrogen receptor in the submandibular and parotid salivary glands of female rats

The purpose of this study was to measure the availability of the estrogen receptor in submandibular and parotid salivary glands in female rats. The presence of a specific, competitive, and saturable estrogen binder in rat salivary gland tissue was determined by saturation analysis and steroid competition in cell-free homogenates of salivary gland tissue from adult ovariectomized females. Scatchard analysis of the data indicated an estrogen receptor content of 1971.1 +/- 651.4 femtomoles/gm of tissue in submandibular salivary gland. This was significantly (p less than 0.01) greater than the number of estrogen binding sites in the parotid gland (457.1 +/- 123.4 femtomoles/gm tissue). Thus, there is a differential distribution in estrogen receptor content between parotid and submandibular salivary glands. The presence of an estrogen receptor in salivary gland tissue may serve to promote gender differences in submandibular salivary gland EGF content, to mediate changes in saliva composition during the female reproductive cycle and to regulate EGF release for cyclic uterine growth.

Inhibition of the nuclear localization of [3H]estradiol in rat uterine tissue in vitro

The temperature coefficient (Q10) for the nuclear-cytoplasmic intracellular distribution of specifically-bound [3H]estradiol is approximately 1.0 over the interval 10-30 degrees C. However, this value increases to 3.19 for the temperature influence upon the nuclear-cytoplasmic localization of hormone between 30 degrees and 37 degrees C. A Q10 value of this magnitude is indicative of a biological, rather than physical, translocation event. In assessment of a biological basis for translocation, several antimicrotubular/antimicrofilamentous agents were used alone and in combination to ascertain their effects upon in vitro nuclear localization of labeled estradiol in the uterus. The incubation of uterine tissue in D2O-Locke-Ringer's solution containing 10(-4) M colchicine or vinblastine significantly reduced the nuclear localization of [3H]estradiol to nonspecific retention. Tissue uptake of the hormone, cytoplasmic binding and retention of estrogen, and the nucleophilic property of the receptor-estrogen complex (REC) were unaffected. Other drug treatments were without effect upon nuclear occupancy of the REC. The apparent inhibition of translocation by the above regimen could be due to an alteration in cellular architecture incompatible with hormone movement or the result of a direct effect upon cellular components which impede the dynamic interactions of REC in nuclei of whole tissue. Although these results do not necessarily imply that a functional cytoskeleton is required for translocation, we suggest that the estrogen-mediated nuclear occupancy of REC is a biological process susceptible to disruption.

The effect of homogenization temperature upon the apparent cellular compartmentalization of unoccupied estrogen receptor

Homogenization of rat uterus at elevated temperatures results in an increased nuclear localization of unoccupied estrogen receptor. This is a nonlinear effect which is accounted for by an increased population of KCl-resistant nuclear binding sites at the elevated homogenization temperatures.

Effect of neonatal exposure to the antioestrogens nafoxidine and CI-628 upon the development of the uterus in the prepubertal rat

Neonatal Sprague-Dawley rats were injected with the antioestrogens nafoxidine or CI-628 on Day 3 of life alone or in combination with oestradiol benzoate 24 h later. Oestrogen-stimulated glucose oxidation and cytoplasmic oestrogen binding sites of the uteri were assessed at 21-23 days of age. Neither antioestrogen antagonized the prepubertal uterine impairments produced by neonatal oestradiol treatment. Both antioestrogens administered alone produced deficits which mimicked those produced by neonatal oestrogenization. However, the agonist property of each antioestrogen was differentially expressed: treatment with CI-628 reduced prepubertal oestrogen binding sites in the uterus, but nafoxidine exposure decreased the sensitivity of the uterus to oestradiol stimulation of glucose oxidation. It is postulated that CI-628 directly affects the uterus to reduce production of oestrogen receptor protein, while nafoxidine affects the development of the uterine phosphogluconate oxidative pathway indirectly through impaired ovarian function. However, antioestrogens blocked the neonatal oestradiol-induced reduction in the oestrogen-stimulated production of actomyosin in the adult uterus. Therefore, while both CI-628 and nafoxidine are clearly agonists in the neonatal rat, each appears to exhibit cell-specific agonist and antagonist properties.

Uterine glucose metabolism in the prepubertal rat treated neonatally with androgen, estrogen, and antihormones

Estrogen secretion during infancy may selectively enhance the phosphogluconate oxidative pathway in the rat uterus, for altered estrogen-stimulated glucose oxidation prepubertally is correlated (+0.91) with impaired ovarian development and not uterine estrogen receptor content.

Effects of chlorpromazine on the inhibition and artifactual elevation of [3H]estradiol binding to estrogen receptors in rat uterine cytosol

Chlorpromazine acts to inhibit the specific binding of estradiol in rat uterine cytosol in vitro at concentrations between 0.1 and 0.75 mM. However, at higher concentrations (1.0-2.0 mM) it causes an apparent increase in binding that is due to free labeled estradiol in the assay buffer which is not adsorbed by the charcoal-dextran. This artifactual elevation can lead to misinterpretations of drug-induced potentiation of receptor sites.

An early effect of testosterone propionate upon hypothalamic function in the neonatal rat

Rats treated neonatally with testosterone propionate exhibit a reduced uterine growth response to estradiol administration prepubertally. This androgen-induced impairment is the consequence of developmental effects on both the ovary and the hypothalamic-pituitary complex, although the latter is the more sensitive.

Impaired prepubertal uterine responsivity after neonatal exposure to steroid hormone esters

Injection of neonatal rats on day 3 after birth with a single dose of 5 microgram or 100 microgram estradiol benzoate (EB) or 30 microgram or 1,250 microgram testosterone propionate (TP) drastically impairs the development of uterine growth response to exogenous estradiol on day 21 of life. Reduction of uterine responsivity was augmented by EB treatment compared to TP treatment. This may be explained by an apparent reduction in available cytoplasmic estrogen binding sites in the uterus with a concomitant decrease in nuclear retention of the receptor-estrogen complex which was in addition to the effect upon estrogen-stimulated metabolic activity (glucose oxidation) resultant from either TP or EB exposure. The degree of reduced uterine responsivity at 21 days of age directly corresponds to the degree of reduction in the ovarian weights observed in the neonatally treated rats. Neonatal ovariectomy on day 3 of life also produced a uterine response syndrome characteristic of neonatal estrogenization. Thus, it is suggested that endogenous estrogen secretion during infancy may be important in end organ conditioning in the development of a functionally competent uterus.

Role of the serum estrogen-binding protein in the control of tissue estradiol levels during postnatal development of the female rat

The role of the serum estrogen-binding protein (EBP) in the control of tissue estradiol levels during postnatal development of the female rat was examined. The estradiol-binding capacity of serum from the 1-day-old rats far exceeded the physiological level of estradiol in serum. The binding capacity decreased exponentially during the first 5 weeks of life to reach the low adult level at about the time of vaginal opening on day 37. From these observations one would predict that EBP would bind estradiol in the serum of the neonate, thereby preventing tissue uptake of the hormone. As the levels of EBP decline with advancing age, there should be a corresponding shift in the distribution of estradiol from serum to tissues. We have taken in vivo and in vitro approaches to evaluate these proposals. Female rats of various ages (1 day to 1 yr old) were sacrificed 1 h after [3H]estradiol injection and the radioactivity in serum and tissues was determined. During the first 11 days of life, the concentration of [3H]estradiol in serum was greater than the concentration of this hormone in estrogen-sensitive (uterus) and insensitive (lung, cerebral cortex, and diaphragm) tissues. Tissue to serum ratios of [3H]estradiol increased progressively between 13-34 days and then plateaued at about the time of puberty (37 days of age) at levels which were 50- to 150-fold greater than those observed in the neonate. The increase in tissue to serum ratios of [3H]estradiol during postnatal development probably resulted from the decline in serum EBP, since injection of neonatal serum into 28-day-old rats reduced tissue to serum ratios of [3H]estradiol to levels which were similar to those observed in 16-day-old animals. To determine the effects of EBP on uterine uptake of estradiol in vitro, uteri from 21-day-old rats were incubated with [3H]estradiol and serum obtained from rats of various ages. As the concentration of serum EBP declined with advancing serum donor age, there was a corresponding increase in the uterine uptake of [3H]estradiol. These results suggest that the decline in EBP is responsible for the progressive increase in tissue to serum ratios of estradiol during the first 5 weeks of life. It is suggested that the increase in tissue to serum ratios of estradiol between days 13-37 postpartum is an important factor in the initiation of estrogenic events during postnatal sexual maturation in the female rat.

Expression of Ly 1, Ly 2, Thy 1, and TL differentiation antigens on mouse T-cell tumors

Transplanted lymphomas, most of thymic origin, induced in BALB/c mice with 1-ethyl-1-nitrosourea (ENU) and transplanted spontaneously occurring lymphomas of AKR mice were examined for the expression of the T-cell antigens Ly, TL, and Thy 1 by using three serological methods. Most (11 of 13) of the Thy 1+ and/or TL+ tumors, i.e., T-cell tumors, expressed high levels of either Ly 1 or Ly 2 antigen, but not both. Thus most thymic lymphocytic tumors expressed restricted Ly phenotypes comparable to phenotypes previously described for functional peripheral T cells. Because tumor phenotypes were stable over a number of transplant generations, they therefore appeared to be an intrinsic property of the specific tumors. The majority of the BALB/c lymphomas were Ly 1- 2+ and also positive with anti-TL antiserum. This predominant phenotype on the BALB/c tumors may be related to either the mode of tumor induction or to the mouse strain, but since the restricted Ly pattern was observed both in BALB/c and AKR tumors, the phenotypic restriction itself is not a consequence of either of these factors. Tumor induction by ENU per se is not responsible for Ly or TL ,ntigen expression since several non-T-cell BALB/ c tumors, also induced by ENU, did not express either Ly or TL antigens. Data presented here suggest that the target cell for leukemogenesis may be a partially differentiated thymus cell. The restricted expression of Ly antigens on differentiating thymus cells to either the (formula: see text), phenotype may occur before the loss of TL antigen.

Synthesis and characterization of membrane immunoglobulin, Ia, and H-2 molecules of thy 1+ AKR/J lymphomas

Three AKR lymphomas displaying B cell and T cell characteristics have been described. Because of the proclivity of normal AKR/J mice to develop T cell lymphomas, and the rarity of lymphomas with dual characteristics, the B cell markers of these tumors were studied more intensively. Fluorescence data with class-specific anti-immunoglobulin reagents demonstrated that the tumor cells stained only with class-specific anti-IgM reagents. Because of the possibility that the surface Ig was passively acquired and of reports that certain anti-mu-chain sera react with "IgT", chemical characterization of the immunoglobulin molecules was performed. Using 3H-leucine internal labeling, we showed that all three tumor lines synthesized the immunoglobulin found on their surface, and that the immunoglobulin had the chemical and immunologic characteristics most typical of monomeric surface IgM, and was composed of mu-chains and light chains. The Ia antigens found on these cells were also examined. These antigens were also synthesized by the cells and were present in the same molecular form and in the same approximate quantity as Ia antigens on normal spleen cells.

Ly phenotype and mechanism of action of mouse neonatal suppressor T cells

Neonatal suppressor T cells were isolated from the thymuses of 10- to 14-day old BDF mice infected at birth with mouse thymic virus. Such cells were enriched for suppressive activity directed against antibody formation by adult B cells and represented a relatively homogenous population of outer cortical cells. Their surface antigen phenotype was found to be: Ly 1+, Ly 2+, TL+, Thy 1+, and H-2+. The cells were larger and contained more DNA than thymocytes from age-matched controls. These findings identify neonatal suppressor T cells as a unique subpopulation separate from most inducible suppressor cells in the adult mouse. The mechanism of action of neonatal suppressor T cells seems to be a reduction in the number of B cells initially triggered by antigen.

Multiple occurrence of spontaneous AKR/J lymphomas with T and B cell characteristics

Three Thy 1.1-positive and surface IgM-positive (Thy 1+, SIg+) AKR/J lymphoma lines are described. These doubly marked tumors arose spontaneously in the peripheral lymphoid organs of 14- to 16-month-old AKR/J mice that either had spontaneous thymus atrophy or had been thymectomized at 1 month of age. All lines bore surface Thy 1.1, Ly,Ig(micron-chain) and Fc receptor (FcR), detectable by immunofluorescence. Immune response region (Iak) antigen was present on the two lines tested. Persistence of Thy 1.1 antigen and SIg after long-term tissue culture provided evidence that these markers were not passively acquired. One of these tumor lines, AkTB-1 always grows in lymph nodes as Thy 1.1-positive,SIg-negative tumors cells, whereas tumor cells growing in the spleen are initially Thy 1.1 positive, SIg negative, but they rapidly acquire SIg, FcR, and 1a between 18 and 21 days of passage.

Pregnancy following coital-induced ovulation in a spontaneous ovulator

Ovulation induced in the immature rat by pregnant mare's serum can be prevented by chlorpromazine. Coitus induces ovulation in such animals, and ovulation so induced may result in pregnancy. Both implantation and pregnancy appear to be normal although the duration of gestation may be prolonged. Decidual response also is produced in the immature rat after coitus-induced ovulation. We suggest that the reflex release of luteinizing hormone may occur in Primates after coitus.