Abstract PD17-12: Primary efficacy and safety results from the AMALEE trial evaluating 600 mg vs 400 mg starting doses of first-line ribociclib in patients with HR+/HER2− advanced breast cancer

Background: In the Phase III MONALEESA (ML)-2, -3 and -7 trials, a 600 mg dose of ribociclib (RIB) demonstrated significant overall survival benefit in patients (pts) with HR+/HER2− advanced breast cancer (ABC) but was associated with QTcF (>480 ms, 3%-7%) and neutropenia (G3/4, 57%-64%) adverse events (AEs) which were managed by dose reductions. The Phase II AMALEE study was performed as a postmarketing commitment to assess whether reducing the starting dose of RIB from the recommended dose (3 wk on, 1 wk off) of 600 mg/day to 400 mg/day decreases QTcF prolongation without compromising the efficacy of first-line RIB in pts with HR+/HER2− ABC. Here, we present efficacy and safety results from the primary analysis of AMALEE. Methods: AMALEE is a randomized Phase II open-label study including pre- and postmenopausal pts with HR+/HER2− ABC with no prior therapy for ABC. Pts received RIB 400 mg + nonsteroidal aromatase inhibitor (NSAI) or RIB 600 mg + NSAI. The primary endpoint is to determine whether overall response rate (ORR) in the 400 mg arm is noninferior to the 600 mg arm. The key secondary endpoint is QTcF prolongation at cycle 1, day 15 (C1D15) 2 hours post dose. Additional endpoints included safety, progression-free survival (PFS), duration of response (DOR), time to response (TTR), and pharmacokinetics. Results: A total of 376 pts were randomized 1:1 to receive RIB at either 400 mg or 600 mg doses. Baseline (BL) characteristics and prior antineoplastic therapy were balanced across treatment (tx) arms. At the time of the data cutoff (June 11, 2021), median follow-up was 14.9 mo (min, 6.1; max, 23.8), and all pts had been treated for ≥6 months from randomization or had discontinued study tx. ORR for RIB was 41.5% (95% CI, 34.4-48.7) with 400 mg vs 45.3% (95% CI, 38.1-52.6) with 600 mg (ORR ratio for RIB 400 mg vs 600 mg, 0.921 [90% CI, 0.757-1.121]). The lower 90% CI boundary did not meet the prespecified noninferiority (NI) margin of 0.814. Results for ORR by subgroups were consistent with the overall analysis set. RIB plasma exposure was lower at 400 mg than 600 mg; the geometric mean Cmax and AUC0-24h at C1D15 were approximately 28% and 43% lower in the 400 mg than the 600 mg arm (Cmax 1080 vs 1500 ng/mL and AUC0-24h 16400 vs 28600 ng × h/mL). This study met the key secondary endpoint, change in QTcF at C1D15 in the RIB 400 mg group with a 90% CI upper boundary of < 20 ms. Mean change in QTcF from BL to C1D15 2 hours post dose was lower in the 400 mg (12.5 ms, 90% CI, 10.9-14.1) than the 600 mg arm (19.7 ms, 90% CI, 17.4-22.0). QTcF ≥501 ms occurred in 1.6% of pts in the 400 mg arm vs 0.5% in the 600 mg arm. Rates of G3/4 neutropenia were lower in the 400 mg (31.4%) than the 600 mg arm (46.3%). Other safety results were consistent with those previously reported for RIB in the ML trials. Median duration of exposure to RIB was 8.0 mo (min, 0.1; max, 23.7) in the 400 mg arm vs 8.8 mo (min, 0.5; max, 20.8) in the 600 mg arm. Dose reductions of RIB were more frequent in the 600 mg group with 30.5% vs 13.8% of pts requiring 1 dose reduction in the 600 mg and 400 mg groups, respectively. Dose reductions were primarily attributable to AEs, with neutropenia being the most frequently reported AE requiring a dose modification. Rates of discontinuation due to AEs were similar in the 400 mg vs 600 mg arms (8.5% vs 9.6%). PFS, DOR, and TTR data are currently immature. Conclusions: RIB at the 400 mg dose shows a better safety profile vs 600 mg in terms of key AEs that are RIB concentration dependent (neutropenia and QTcF prolongation). ORR was 3.8% lower with 400 mg than 600 mg. The lower 90% CI boundary of the ORR ratio did not meet the NI margin, thus this study was unable to demonstrate statistical NI of the 400 mg vs 600 mg dose of RIB using ORR as the endpoint. Updated results with additional follow-up and the clinically relevant endpoint PFS will be presented at the congress.

Citation Format: Fatima Cardoso, William Jacot, Sherko Küemmel, Sudeep Gupta, Rama Balaraman, Liudmila Lebedeva, Yan Ji, Aparna Lakshmanan, Khalid Amin, Zheng Li, Joseph Sparano. Primary efficacy and safety results from the AMALEE trial evaluating 600 mg vs 400 mg starting doses of first-line ribociclib in patients with HR+/HER2− advanced breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD17-12.

Nematicidal Properties of Chitosan Nanoformulation

Chitosan is the second most abundant bio-polymer available in the world, second only to cellulose. It is found in crustaceous shells, e.g., those of crabs, shrimps, prawns, and fungi, as well as insect exoskeletons. The use of nanoformulations for the management of pests and diseases is receiving increased interest with the advancement of nanotechnology. Here, chitosan nanospheres were obtained from chitosan using the ionic gelation technique. The nanoformulations obtained were characterized using a particle size analyzer, Fourier transform infrared spectroscopy, and a transmission electron microscope. The efficacy of chitosan nanospheres in suppressing the root-knot nematode Meloidogyne incognita was studied. The particle size of nanospheres formulated for this study was 380.2 nm, with a polydispersity index (PI) of 0.4 and Zeta potential of 45.7 or 50.9 mV at pH 5.2. The chitosan nanospheres were spherical and the particles did not agglomerate. FTIR spectra of the chitosan nanospheres peaked at 3334 cm-1, thereby indicating the stretching of the OH and NH group. In In-vitro studies, chitosan nanospheres showed significant nematicidal activity against M. incognita. Under pot culture conditions, chitosan nanospheres (1%- active compound chitosan) at 2ml/plant decreased the nematode population in roots or soil. Compared to the control, the number of galls was reduced by 83.68%, the number of egg masses by 83.85%, the number of adult females by 66.56%, and the number of second-stage juveniles by 73.20%. In a field experiment, application of chitosan nanospheres (1%) was followed by a 18.75% increase in fruit yield compared to the non-treated control.

Surgical management of patent ductus arteriosus in pre-term infants - a british paediatric surveillance study

Background

This study aimed to provide UK data describing the incidence of patent ductus arteriosus (PDA) surgery in the neonatal population, including: pre-ligation management, and outcomes until discharge. We used British Paediatric Surveillance Unit (BPSU) methodology; collecting data via questionnaires for preterm neonates undergoing PDA ligation (PDAL) between 1st Sept 2012 – 30th Sept 2013. Infants born less than 37 weeks gestation, who underwent PDAL prior to discharge home, with no other structural cardiac abnormality, were included. Information collected included: patient demographics, pre and post-operative clinical characteristics, pre-operative medical management, post-operative complications and outcome.

Results

Over the study, 263 infants underwent PDAL an incidence of 3.07 per 10,000 live births. 88% were born extremely preterm (< 28 weeks) and 60% were male. The commonest reasons for ligation were inability to wean respiratory support (83.7%) and haemodynamically significant PDA (87.8%). Pre-operatively 65.7% received medical therapy. Surgery was performed at a median age of 33 days (range 9-260, IQR 24-48); the corrected age was less than 31 + 6 week in 50.6% babies at PDAL. Most, (90%), of procedures were open ligation; only 9 (3.4%) were catheter occlusions (PDACO). 20.5% of patients had post-operative complications. The 30-day mortality was 3%, with 93.5% surviving to hospital discharge.

Conclusion

This study showed there was little consensus over medical and surgical management of the PDA or timing of surgery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02734-9.

Abstract P4-14-05: Confirmation of the TAILORx 21-gene expression trial using a real world observational database

Background: The TAILORx study (NCT00310180)(TRx) has demonstrated the efficacy of endocrine therapy alone in early stage, lymph node negative, hormone receptor positive, her2neu oncogene negative breast cancer harboring an intermediate recurrence score (RS) on a 21-gene profile (OncotypeDx), obviating the need for adjuvant chemotherapy in a large subset of women. The study randomized and followed 6711 patients (pts) and required 9 years to reach its conclusion endpoints. The availability of the electronic health record (EHR) permits automated reviews, facilitating more rapid “real world” hypothesis testing (but not a replacement for randomized clinical trials), especially when there are clear variations in common practice patterns. However physician bias in treatment selection needs to be considered.

Methods: A retrospective review of the Cota Observational Cancer database, drawn from EHRs, of female pts with breast cancer who were 18 to 75 years of age; had hormone-receptor–positive, human epidermal growth factor receptor 2 (HER2)–negative, axillary node–negative breast cancer harboring an OncotypeDx RS 11-25 receiving adjuvant therapy following surgical resection of a 11-50 mm primary tumor (similar to TRx eligibility).

Results: 1009 pts from 23 cancer centers (107 oncologists) were identified, 850 (84.2%) received adjuvant endocrine therapy alone (E) and 159 (15.8%) received adjuvant chemoendocrine therapy (CE) as part of standard care (no randomization). 285 pts were age &lt;50 yrs (E:218, CE:67) and 601 pts has RS 16-25 (E:453, CE:148). Treatment selection was imbalanced with oncologists more likely to utilize CE in younger pts (median age E: 59 yrs, CE: 53 yrs; p&lt;0.01), larger tumors (median tumor size E: 16mm, CE: 20mm; p&lt;0.001) and higher RS (median RS E: 16, CE: 21; p&lt;0.001). With a median follow-up for survival since diagnosis of 3.7 years, the Kaplan-Meier estimated 5 yr overall survival rates were 98.9% with E and 97.8% with CE (p=0.23); the corresponding 5-yr OS in TRx were E: 98% and C: 98.1%. With a median 1.7 years follow-up for recurrence, 19 pts have suffered a disease distant or local recurrence (E: 13, CE: 6) yielding a 5-year recurrence-free survival of E: 95.2% and CE: 91% (p=0.05); the corresponding TRx result was E: 96.9% and CE: 97%. The 5-yr invasive disease-free survival (IDFS = death, local/distant, second primary) with 32 events was E: 92.7% and CE: 81.9% (p= 0.05); corresponding TRx E: 92.8 % and CE: 93.1%. Given the imbalance in treatment allocations, a multivariate analysis was performed, with older age (&lt;0.001), CE choice (&lt;0.006) and larger tumor size (p&lt;0.05) remaining significant, but not increased RS (p=0.16) for 5-year IDFS. Among women age &lt;50 with RS 16-25 (E: 118; CE: 60) the 5-yr IDFS was E: 95% and CE: 94%; the corresponding RS 16-20 TRx E: 92% and CE: 94.7% and RS 21-25 E: 86.3% and CE: 92.1%.

Conclusions: Using a real world data source, endocrine therapy alone appears to yield excellent 5-yr survival rates among pts with 21-gene RS 11-25 similar to the TAILORx trial. Treatment selection bias (with perceived higher risk pts allocated to CE) and shorter median follow-up limits full confirmation by this dataset.

Citation Format: Waintraub SE, Isaacs C, Norden AD, Graham DA, McNamara DM, O'Neill SC, Lakshmanan A, Wu T, Maresca A, Pecora AL, Goy AH, Goldberg SL. Confirmation of the TAILORx 21-gene expression trial using a real world observational database [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-14-05.

Spotlight on Ibrutinib in PCNSL: Adding Another Feather to Its Cap

<b/> In this issue Grommes and colleagues elegantly show that the irreversible inhibitor of Bruton tyrosine kinase, ibrutinib, promotes a high proportion of durable responses in primary central nervous system lymphoma, a type of diffuse large B-cell lymphoma (DLBCL), and also in secondary DLBCL relapsing to the central nervous system. Mutations in the B-cell antigen receptor-associated protein CD79B with upregulation of the MTOR pathway were associated with diminished response, but preclinical combination of PIK3CA and PIK3CD inhibitors synergized with ibrutinib to overcome this resistance mechanism, providing opportunity for further targeted therapy of this difficult-to-treat disease. Cancer Discov; 7(9); 940-2. ©2017 AACRSee related article by Grommes et al., p. 1018.

Abstract 1029: MAPK-mediated immunomodulation in disseminated murine Emu-TCL1 chronic lymphocytic leukemia

Work in melanoma and other solid tumors shows mutations activating MAPK pathway not only promote malignancy by promoting survival and proliferation but also are immunosuppressive than wild-type (WT) counterparts. However, relevance of MAPK-activating mutations to immune modulation in disseminated cancers such as leukemia is uncertain, and the mechanisms by which this occurs are likely to differ. BRAF activating mutation is found in nearly all hairy cell leukemia cases, 4% of chronic lymphocytic leukemia (CLL) and 9% CLL cases when including other MAPK-activating mutations such as KRAS and NRAS. To assess immunomodulatory effects of BRAF-mutant CLL cells, we co-cultured dox-inducible OSU-CLL cells transfected with WT or BRAFV600E constructs with healthy donor T cells incubated with anti-CD3/anti-CD28 antibodies, and T cell proliferation, cytokine production and expression of surface proteins were assessed by flow cytometry. We also employed a transgenic mouse model of BRAF B cell leukemia. CD19-Cre x BRAFV600E or CD19-Cre only mice were crossed with the well-characterized Emu-TCL1 model of CLL to obtain mice with spontaneous B cell leukemia expressing either WT BRAF (CD19-Cre xTCL1) or mutant BRAF (BRAFV600E xCD19-Cre xTCL1) under the native BRAF promoter. For adoptive transfer (AT) experiments, leukemia cells (2e7) from transgenic mice were engrafted intravenously into syngeneic healthy adult animals. Blood and spleen cells were examined by flow cytometry. OSU-CLL cells expressing BRAFV600E more strongly inhibited anti-CD3/CD28-induced proliferation of normal donor T cells. Transwell assays showed this effect was due both to soluble and contact-dependent factors. TNF levels were higher in BRAFV600E-expressing cells and reduced by vemurafenib, but a TNF neutralizing antibody did not alter the inhibitory effect of BRAFV600E-expressing cells on T cell proliferation. Proliferation was rescued by the BRAFV600E inhibitor dabrafenib, further supporting the contribution of mutant BRAF to this effect. Impact of BRAFV600E mutation on myeloid compartment was also evaluated using AT model. Mice were engrafted with BRAFWT or BRAFV600E leukemia cells, and upon achieving similar disease loads, BRAFV600E leukemic B cells caused 2.2-fold increase in PD-L1 expressing-peripheral myeloid cells (p&lt;0.001; n=25 WT; 11 mutant). Additionally, there was an increase in F4/80+ macrophages (11%; p=0.002), CD11b+Ly6CintLy6Ghi MDSCs (8.5%, p=0.014) and decrease in CD11b+Ly6CloLy6Glo patrolling monocytes (11%; p=0.031; n=33 WT; 40 mutant) in spleens of mice with BRAFV600E leukemia, indicating that this mutation influences the myeloid cell compartment as well. Ongoing studies are investigating the mechanism of these effects and the potential for pharmacologic reversal. Together, these results demonstrate immunosuppressive impact of BRAF in B-cell leukemia.

Citation Format: Aparna Lakshmanan, Yo-Ting Tsai, Amy Lehman, Ellen J. Sass, Minh Tran, Fabienne Lucas, Meixiao Long, Bonnie K. Harrington, Krista La Perle, Vincenzo Coppola, Gerard Lozanski, Natarajan Muthusamy, John C. Byrd, Michael R. Grever, David M. Lucas. MAPK-mediated immunomodulation in disseminated murine Emu-TCL1 chronic lymphocytic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1029. doi:10.1158/1538-7445.AM2017-1029

Cost consciousness among physicians in the neonatal intensive care unit

OBJECTIVE

The objectives of this study were (1) to describe the prevalence and correlates of cost consciousness among physician providers in neonatology and (2) to describe knowledge of cost of common medications, laboratory/imaging evaluations, hospitalization costs and reimbursements.

STUDY DESIGN

A 54-item survey was administered to members of the Section on Neonatal-Perinatal Medicine of the American Academy of Pediatrics.

RESULTS

Of the 602 participants, 37% reported cost consciousness in decision making. Adjusting for years in practice, gender, training level, type of practice setting and region of practice, formalized education about costs was associated with increased cost consciousness in practice (adjusted odds ratio (AOR): 3.4; 95% confidence interval (CI): 1.2 to 9.8). Working in a private practice setting was also associated with increased cost consciousness when ordering laboratory (AOR: 3.0; (95% CI: 1.2 to 7.6)) or imaging tests (AOR: 2.0; 95% CI: 1.0 to 4.8).

CONCLUSIONS

We found variation in knowledge of cost. Formal education about costs and working in a private practice setting were associated with increased cost consciousness.

Modulation of thyroidal radioiodide uptake by oncological pipeline inhibitors and Apigenin

Targeted radioiodine therapy for thyroid cancer is based on selective stimulation of Na+/I- Symporter (NIS)-mediated radioactive iodide uptake (RAIU) in thyroid cells by thyrotropin. Patients with advanced thyroid cancer do not benefit from radioiodine therapy due to reduced or absent NIS expression. To identify inhibitors that can be readily translated into clinical care, we examined oncological pipeline inhibitors targeting Akt, MEK, PI3K, Hsp90 or BRAF in their ability to increase RAIU in thyroid cells expressing BRAFV600E or RET/PTC3 oncogene. Our data showed that (1) PI3K inhibitor GDC-0941 outperformed other inhibitors in RAIU increase mainly by decreasing iodide efflux rate to a great extent; (2) RAIU increase by all inhibitors was extensively reduced by TGF-β, a cytokine secreted in the invasive fronts of thyroid cancers; (3) RAIU reduction by TGF-β was mainly mediated by NIS reduction and could be reversed by Apigenin, a plant-derived flavonoid; and (4) In the presence of TGF-β, GDC-0941 with Apigenin co-treatment had the highest RAIU level in both BRAFV600E expressing cells and RET/PTC3 expressing cells. Taken together, Apigenin may serve as a dietary supplement along with small molecule inhibitors to improve radioiodine therapeutic efficacy on invasive tumor margins thereby minimizing future metastatic events.

Epidemiological and clinical pattern of dermatomycoses in rural India

Superficial fungal infections are most common in tropical and subtropical countries. In this study, 297 suspected superficial fungal infection cases were identified among 15,950 patients screened. The collected samples (skin, nail, and hair) were subjected to direct microscopy with potassium hydroxide and cultured on Sabourauds dextrose agar to identify the fungal species. The prevalence of superficial fungal infection was 27.6% (82/297), dermatophytosis was 75.6% (62/82), and non-dermatophytosis was 24.4% (20/82). Among the isolated dermatophytes, Trichophyton rubrum was the commonest species (79%) and Candida (60%) the commonest non-dermatophytic species. Tinea corporis was the commonest (78%) clinical presentation.

microRNA-339-5p modulates Na+/I- symporter-mediated radioiodide uptake

Na(+)/I(-) symporter (NIS)-mediated radioiodide uptake (RAIU) serves as the basis for targeted ablation of thyroid cancer remnants. However, many patients with thyroid cancer have reduced NIS expression/function and hence do not benefit from radioiodine therapy. microRNA (miR) has emerged as a promising therapeutic target in many diseases; yet, the role of miRs in NIS-mediated RAIU has not been investigated. In silico analysis was used to identify miRs that may bind to the 3'UTR of human NIS (hNIS). The top candidate miR-339-5p directly bound to the 3'UTR of hNIS. miR-339-5p overexpression decreased NIS-mediated RAIU in HEK293 cells expressing exogenous hNIS, decreased the levels of NIS mRNA, and RAIU in transretinoic acid/hydrocortisone (tRA/H)-treated MCF-7 human breast cancer cells as well as thyrotropin-stimulated PCCl3 rat thyroid cells. Nanostring nCounter rat miR expression assay was conducted to identify miRs deregulated by TGFβ, Akti-1/2, or 17-AAG known to modulate RAIU in PCCl3 cells. Among 38 miRs identified, 18 were conserved in humans. One of the 18 miRs, miR-195, was predicted to bind to the 3'UTR of hNIS and its overexpression decreased RAIU in tRA/H-treated MCF-7 cells. miR-339-5p was modestly increased in most papillary thyroid carcinomas (PTCs), yet miR-195 was significantly decreased in PTCs. Interestingly, the expression profiles of 18 miRs could be used to distinguish most PTCs from nonmalignant thyroid tissues. This is the first report, to our knowledge, demonstrating that hNIS-mediated RAIU can be modulated by miRs, and that the same miRs may also play roles in the development or maintenance of thyroid malignancy. Accordingly, miRs may serve as emerging targets to halt the progression of thyroid cancer and to enhance the efficacy of radioiodine therapy.

Modulation of sodium iodide symporter in thyroid cancer

Radioactive iodine (RAI) is a key therapeutic modality for thyroid cancer. Loss of RAI uptake in thyroid cancer inversely correlates with patient's survival. In this review, we focus on the challenges encountered in delivering sufficient doses of I-131 to eradicate metastatic lesions without increasing the risk of unwanted side effects. Sodium iodide symporter (NIS) mediates iodide influx, and NIS expression and function can be selectively enhanced in thyroid cells by thyroid-stimulating hormone. We summarize our current knowledge of NIS modulation in normal and cancer thyroid cells, and we propose that several reagents evaluated in clinical trials for other diseases can be used to restore or further increase RAI accumulation in thyroid cancer. Once validated in preclinical mouse models and clinical trials, these reagents, mostly small-molecule inhibitors, can be readily translated into clinical practice. We review available genetically engineered mouse models of thyroid cancer in terms of their tumor development and progression as well as their thyroid function. These mice will not only provide important insights into the mechanisms underlying the loss of RAI uptake in thyroid tumors but will also serve as preclinical animal models to evaluate the efficacy of candidate reagents to selectively increase RAI uptake in thyroid cancers. Taken together, we anticipate that the optimal use of RAI in the clinical management of thyroid cancer is yet to come in the near future.

Apigenin in combination with Akt inhibition significantly enhances thyrotropin-stimulated radioiodide accumulation in thyroid cells

BACKGROUND

Selectively increased radioiodine accumulation in thyroid cells by thyrotropin (TSH) allows targeted treatment of thyroid cancer. However, the extent of TSH-stimulated radioiodine accumulation in some thyroid tumors is not sufficient to confer therapeutic efficacy. Hence, it is of clinical importance to identify novel strategies to selectively further enhance TSH-stimulated thyroidal radioiodine accumulation.

METHODS

PCCl3 rat thyroid cells, PCCl3 cells overexpressing BRAF(V600E), or primary cultured tumor cells from a thyroid cancer mouse model, under TSH stimulation were treated with various reagents for 24 hours. Cells were then subjected to radioactive iodide uptake, kinetics, efflux assays, and protein extraction followed by Western blotting against selected antibodies.

RESULTS

We previously reported that Akt inhibition increased radioiodine accumulation in thyroid cells under chronic TSH stimulation. Here, we identified Apigenin, a plant-derived flavonoid, as a reagent to further enhance the iodide influx rate increased by Akt inhibition in thyroid cells under acute TSH stimulation. Akt inhibition is permissive for Apigenin's action, as Apigenin alone had little effect. This action of Apigenin requires p38 MAPK activity but not PKC-δ. The increase in radioiodide accumulation by Apigenin with Akt inhibition was also observed in thyroid cells expressing BRAF(V600E) and in primary cultured thyroid tumor cells from TRβ(PV/PV) mice.

CONCLUSION

Taken together, Apigenin may serve as a dietary supplement in combination with Akt inhibitors to enhance therapeutic efficacy of radioiodine for thyroid cancer.

Abstract 87: Apigenin further enhances Akti1/2-induced radioactive iodine uptake (RAIU) and rescues TGF-β1-reduced RAIU in PCCl3 rat thyroid cells

Background: Na+/I− Symporter (NIS) is a glycoprotein expressed on the basolateral membrane of thyroid follicular cells and it facilitates iodide uptake from circulating blood. In thyroid cancer, NIS-mediated RAIU serves as the basis for therapeutic ablation of post-thyroidectomy remnants. However, patients with advanced thyroid cancer do not benefit from radioiodine therapy due to reduced or absence of NIS expression/function. Thus, it is of clinical importance to investigate the underlying mechanisms of NIS modulation such that strategies to selectively upregulate NIS expression/ function can be devised.

Approach: Clinical and experimental evidences suggest an inverse correlation between Epithelial-to-mesenchymal transition (EMT) and NIS-mediated RAIU in thyroid cancer. To investigate if there is a functional role for EMT in decreasing RAIU, we determined the expression levels of 83 EMT-associated genes in PCCl3 rat thyroid cell lines treated with DMSO (control), Akti1/2 (small molecule inhibitor of pAkt1/2 known to increase RAIU) or TGF-β1 (cytokine known to decrease RAIU) using SABiosciences RT2 profiler EMT PCR array and subjected the results to Ingenuity Pathway Analysis (IPA). To mimic clinical conditions, cells were subjected to ≈5-day Thyroid Stimulating Hormone (TSH) withdrawal followed by acute stimulation by TSH for 24h. Cells were then treated for 24h with reagents in the presence of TSH followed by RNA extraction or RAIU assay or protein isolation.

Results: From IPA analysis, we predicted apigenin, a plant derived flavonoid could potentially increase radioactive iodide uptake. Indeed, in-vitro RAIU assays and western blots revealed that apigenin (20μM) further enhances Akti1/2 (10μM)-induced RAIU up to 2-fold by increasing iodide influx and not by increasing NIS protein levels or decreasing iodide efflux in thyroid cells. pAkt inhibition was permissive for apigenin to increase RAIU. Apigenin (20μM) also rescued TGF-β1 (10ng/ml)-reduced RAIU up to 85%. Apigenin is known to affect many kinases and the molecular mechanism of action of apigenin in increasing RAIU is currently under investigation using candidate approach.

Conclusion: Apigenin is the only compound reported so far that consistently further increases Akti1/2-induced RAIU. Apigenin promises to reveal novel molecular mechanisms of NIS modulation in thyroid. Apigenin also serves as a potential candidate for dietary supplement in combination with other drugs for future efficacy studies related to radioiodide therapy of thyroid cancer.

Citation Format: Aparna Lakshmanan, Sissy Meihua Jhiang. Apigenin further enhances Akti1/2-induced radioactive iodine uptake (RAIU) and rescues TGF-β1-reduced RAIU in PCCl3 rat thyroid cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 87. doi:10.1158/1538-7445.AM2013-87

KT5823 differentially modulates sodium iodide symporter expression, activity, and glycosylation between thyroid and breast cancer cells

Na(+)/I(-) symporter (NIS)-mediated iodide uptake into thyroid follicular cells serves as the basis of radioiodine therapy for thyroid cancer. NIS protein is also expressed in the majority of breast tumors, raising potential for radionuclide therapy of breast cancer. KT5823, a staurosporine-related protein kinase inhibitor, has been shown to increase thyroid-stimulating hormone-induced NIS expression, and thus iodide uptake, in thyroid cells. In this study, we found that KT5823 does not increase but decreases iodide uptake within 0.5 h of treatment in trans-retinoic acid and hydrocortisone-treated MCF-7 breast cancer cells. Moreover, KT5823 accumulates hypoglycosylated NIS, and this effect is much more evident in breast cancer cells than thyroid cells. The hypoglycosylated NIS is core glycosylated, has not been processed through the Golgi apparatus, but is capable of trafficking to the cell surface. KT5823 impedes complex NIS glycosylation at a regulatory point similar to brefeldin A along the N-linked glycosylation pathway, rather than targeting a specific N-glycosylated site of NIS. KT5823-mediated effects on NIS activity and glycosylation are also observed in other breast cancer cells as well as human embryonic kidney cells expressing exogenous NIS. Taken together, KT5823 will serve as a valuable pharmacological reagent to uncover mechanisms underlying differential NIS regulation between thyroid and breast cancer cells at multiple levels.

Intraorbital organic foreign body--a diagnostic challenge

Intraorbital organic foreign bodies pose a diagnostic and management challenge to ophthalmologists. A high degree of suspicion of an orbital foreign body is needed when patients present with injuries to the eyelids and orbit. We present a case of retained intraorbital wooden foreign body which was initially undetected. A 10-year-old boy presented to the eye casualty with signs and symptoms suggestive of orbital cellulitis. He was started on intravenous antibiotics and urgent CT of the orbits did not reveal any foreign bodies. There was spontaneous extrusion of a wooden foreign body through the upper lid two days later, followed by spontaneous resolution of symptoms. Wood has a density similar to air and fat and can be difficult to distinguish from soft tissue in both a plain X-ray film and a computed tomogram. Clinicians should be alerted to the possibility of retention of an intraorbital foreign body in all patients presenting with periorbital trauma. The clinician should also obtain a careful history of the type of injury and should examine the patient in detail. In cases where a wooden foreign body is suspected, investigation by magnetic resonance imaging is preferred.