A Novel Thienopyrimidine Analog, TPH104, Mediates Immunogenic Cell Death in Triple-Negative Breast Cancer Cells

Simple Summary

Triple-negative breast cancer (TNBC) is the most lethal and aggressive subtype of breast cancer that lacks an estrogen receptor, the progesterone receptor and the human epidermal growth factor receptor 2 (HER2), making it unsuitable for hormonal- or HER2-based therapy. TNBC is known for its higher relapse rate, poorer prognosis and higher rate of metastasis compared to non-TNBC because although patients initially respond to chemotherapy that kills cancer cells through a form of programmed cell death called apoptosis, they later develop chemoresistance and stop responding to the treatment, accounting for one fourth of all breast cancer deaths. In this study, we report a novel compound, TPH104, that elicits a unique, non-apoptotic cell death in TNBC cells. Upon treatment with TPH104, TNBC cells swell and burst, releasing immunogenic markers that alert and activate the immune system to further recognize and attack the neighboring breast cancer cells.

Abstract

Enhancing the tumor immunogenic microenvironment has been suggested to circumvent triple-negative breast cancer (TNBC) resistance and increase the efficacy of conventional chemotherapy. Here, we report a novel chemotherapeutic compound, TPH104, which induces immunogenic cell death in the TNBC cell line MDA-MB-231, by increasing the stimulatory capacity of dendritic cells (DCs), with an IC₅₀ value of 140 nM. TPH104 (5 µM) significantly increased ATP levels in the supernatant and mobilized intracellular calreticulin to the plasma membrane in MDA-MB-231 cells, compared to cells incubated with the vehicle. Incubating MDA-MB-231 cells for 12 h with TPH104 (1–5 µM) significantly increased TNF-α mRNA levels. The supernatants of dying MDAMB-231 cells incubated with TPH104 increased mouse bone marrow-derived DC maturation, the expression of MHC-II and CD86 and the mRNA expression of TNF-α, IL-6 and IL-12. Overall, these results indicate that TPH104 induces immunogenic cell death in TNBC cells, in part, by activating DCs.

Moderately Hypofractionated Intensity Modulated Radiation Therapy With Simultaneous Integrated Boost for Prostate Cancer: Five-Year Toxicity Results From a Prospective Phase I/II Trial

BACKGROUND

In this phase I/II trial, 5-year physician-assessed toxicity and patient reported quality of life data is reported for patients undergoing moderately hypofractionated intensity modulated radiation therapy (IMRT) for prostate cancer using a simultaneous integrated boost (SIB) and pelvic lymph node (LN) coverage.

MATERIALS AND METHODS

Patients with T1-T2 localized prostate cancer were prospectively enrolled, receiving risk group based coverage of prostate ± seminal vesicles (SVs) ± pelvic lymph nodes (LNs). Low risk (LR) received 69.6 Gy/29 fractions to the prostate, while intermediate risk (IR) and high risk (HR) patients received 72 Gy/30fx to the prostate and 54Gy/30fx to the SVs. If predicted risk of LN involvement >15%, 50.4 Gy/30fx was delivered to pelvic LNs. Androgen deprivation therapy was given to IR and HR patients.

RESULTS

There were 55 patients enrolled and 49 patients evaluable at a median follow up of 60 months. Included were 11 (20%) LR, 23 (41.8%) IR, and 21 (38.2%) HR patients. Pelvic LN treatment was given in 25 patients (51%). Prevalence rates of late grade 2 GI toxicity at 1, 3, and 5 years was 5.8, 3.9, and 5.8%, respectively, with no permanent grade 3 events. Prevalence rates of late grade 2 GU toxicity at 1, 3, and 5 years rates were 15.4, 7.7, and 13.5%, respectively, with three grade 3 events (5.8%). The biochemical relapse free survival at 5 years was 88.3%. There were no local, regional, or distant failures, with all patients still alive at last follow up.

CONCLUSION

Moderate hypofractionation of localized prostate cancer utilizing a SIB technique and LN coverage produces tolerable acute/late toxicity. Given equivalent efficacy between moderate hypofractionation schedules, the optimal regimen will be determined by long-term toxicity reported from both the physician and patient perspective.

CLINICAL TRIAL REGISTRATION

www.ClinicalTrials.gov, identifier NCT01117935, Date of Registration: 5/6/2010.

Abstract 2406: Novel thienopyrimidine analog TPH104 induces immunogenic cell death in TNBC cells

Background: Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with high propensity for metastasis and recurrence, accounting for one-fourth of all breast cancer deaths. Despite being chemo-sensitive to anthracyclines and taxanes, TNBCs have poor prognosis due to development of resistance often due to the overexpression of efflux transporters, increased DNA repair, and occurrence of genetic mutations that decrease the likelihood of apoptosis. Recently, we discovered a novel class of thieno-pyrimidin-hydrazinyl (TPH) compounds that in the nanomolar range, selectively elicited a unique, caspase-independent cell death in TNBC cells. The lead compound, TPH104, selectively activates receptor interacting protein kinase 1 (RIPK1), thus inducing a necroptosis like cell death. Since necroptosis is known to release endogenous immunogenic markers, we wanted to study whether TPH104 can promote immunogenic cell death (ICD) in TNBC cells and activate cells in the tumor immune milieu. ICD is characterized by presence of damage-associated molecular patterns (DAMPs) such as cell surface exposure of calreticulin (CRT), secretion of ATP, and release of high-mobility group box protein B1 (HMGB1) from dying tumor cells.

Methods: Human TNBC cell line MDA-MB-231 cells were treated with TPH104 and cell survival was examined by 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT), clonogenic and live-cell imaging assays. Western blot analysis was used to assess death signal transducers. DAMPs were examined by ELISA, luminescence-based assay systems and immunofluorescence. Activation of mouse bone marrow derived dendritic cells (BMDCs) in response to conditioned media (CM) harvested after treatment of MDA-MB-231 cells with TPH104 (TPH104-CM) and/or mitoxantrone (MX, positive control) for 48h was evaluated using flow cytometry analysis of maturation markers (CD86, MHCII) expressed on CD11C+ BMDCs. Inflammatory gene expression was evaluated by q-PCR.

Results: The results demonstrated that TPH104 reduced cell survival and induced death of MDA-MB-231 cells in a dose-dependent pattern. TPH104 induced ICD, as evidenced by increased release of ATP, as well as surface exposure of CRT. Flow cytometric analysis revealed TPH104-CM treatment increased CD11C+CD86+MHC+ BMDCs as robustly as MX-CM. Further, TPH104 posed no toxicity to mice in a single dose toxicity study.

Conclusion: TPH104 induced selective ICD in MDA-MB-231 cells. TPH104 similar to MX primed cells to ICD and increased extracellular ATP levels and surface exposure of CRT. TPH104 promoted maturation of CD11C+ BMDCs and increased inflammatory gene expression. Our study demonstrated TPH104 as an ICD-inducer and immunomodulator in TNBC.

Citation Format: Diwakar Bastihalli Tukaramrao, Siddharth Saraiya, Ross A. Hanely, Saloni Malla, Amit K. Tiwari. Novel thienopyrimidine analog TPH104 induces immunogenic cell death in TNBC cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2406.

Five-year results from a phase I/II study of moderately hypofractionated intensity-modulated radiation therapy (IMRT) for localized prostate cancer including simultaneously integrated boost and pelvic lymph node (LN) coverage

299

Background: This study reports the 5 year toxicity and efficacy data of a phase I/II trial of moderately hypofractionated intensity modulated radiation therapy (IMRT) for localized prostate cancer utilizing a simultaneous integrated boost and pelvic lymph node (LN) coverage. Methods: Men with localized prostate cancer were prospectively enrolled and received IMRT to the prostate +/- seminal vesicles (SVs) +/- LNs based on National Comprehensive Cancer Network (NCCN) guidelines. Low-risk (LR) patients received 69.6 Gy in 29 fractions to the prostate alone; intermediate-risk (IR) and high-risk (HR) patients received 72Gy to the prostate, 54Gy to the SVs, and 50.4Gy to LNs (if risk of LN involvement > 15% by the Roach formula) all in 30 fractions. IR and HR patients received androgen deprivation therapy. Results: Fifty-five patients were enrolled and 49 patients evaluable with a median follow up of 60 months. There were 11 (20%) LR, 23 (41.8%) IR, and 21 (38.2%) HR patients. Twenty-five patients (51%) received prostate and LN treatment. At 5 years, the cumulative incidence of late grade 2+ gastrointestinal (GI) and genitourinary (GU) toxicity was 22.6% and 38.2% respectively. Prevalence rates of late grade 2 GI toxicity at 1, 3, and 5 years was 5.8%, 3.9%, and 5.8% respectively. Late grade 2+ GI toxicities that did not resolve by 60 months included 3 out of 52 patients (5.8%). Prevalence rates of late grade 2 GU toxicity at 1, 3, and 5 years rates were 15.4%, 7.7%, and 13.5% respectively. There were 3 patients (5.8%) who experienced grade 3 GU toxicity and no grade 3 GI toxicities. The biochemical relapse free survival at 5 years for the cohort was 88.3%. There were no local, regional, or distant failures, with all patients still alive at last follow up. Conclusions: Moderate hypofractionation of localized prostate cancer utilizing a simultaneous integrated boost and LN coverage produces excellent biochemical control and acceptable acute/late toxicity. This phase I/II trial adds to maturing data with 5 year outcomes which justify its use for cost and patient convenience factors. Clinical trial information: NCT01117935.

Variabilities of Magnetic Resonance Imaging-, Computed Tomography-, and Positron Emission Tomography-Computed Tomography-Based Tumor and Lymph Node Delineations for Lung Cancer Radiation Therapy Planning

PURPOSE

To investigate interobserver delineation variability for gross tumor volumes of primary lung tumors and associated pathologic lymph nodes using magnetic resonance imaging (MRI), and to compare the results with computed tomography (CT) alone- and positron emission tomography (PET)-CT-based delineations.

METHODS AND MATERIALS

Seven physicians delineated the tumor volumes of 10 patients for the following scenarios: (1) CT only, (2) PET-CT fusion images registered to CT ("clinical standard"), and (3) postcontrast T1-weighted MRI registered with diffusion-weighted MRI. To compute interobserver variability, the median surface was generated from all observers' contours and used as the reference surface. A physician labeled the interface types (tumor to lung, atelectasis (collapsed lung), hilum, mediastinum, or chest wall) on the median surface. Contoured volumes and bidirectional local distances between individual observers' contours and the reference contour were analyzed.

RESULTS

Computed tomography- and MRI-based tumor volumes normalized relative to PET-CT-based volumes were 1.62 ± 0.76 (mean ± standard deviation) and 1.38 ± 0.44, respectively. Volume differences between the imaging modalities were not significant. Between observers, the mean normalized volumes per patient averaged over all patients varied significantly by a factor of 1.6 (MRI) and 2.0 (CT and PET-CT) (P=4.10 × 10^-5 to 3.82 × 10^-9). The tumor-atelectasis interface had a significantly higher variability than other interfaces for all modalities combined (P=.0006). The interfaces with the smallest uncertainties were tumor-lung (on CT) and tumor-mediastinum (on PET-CT and MRI).

CONCLUSIONS

Although MRI-based contouring showed overall larger variability than PET-CT, contouring variability depended on the interface type and was not significantly different between modalities, despite the limited observer experience with MRI. Multimodality imaging and combining different imaging characteristics might be the best approach to define the tumor volume most accurately.

Phase I/II study of hypofractionated intensity modulated radiotherapy (IMRT) for prostate cancer including simultaneously integrated boost (SIB)

67

Background: The purpose of this study is to evaluate the toxicity of hypofractionationed H- IMRT treatment including SIB IMRT when pelvic nodes were covered. Additionally, we assessed early treatment efficacy through PSA control (biochemical failure defined as PSA more than nadir + 2 ng/mL). Methods: Men with localized prostate cancer were enrolled in a phase I/II trial to receive H-IMRT to the prostate, seminal vesicles)(SV) and pelvic lymph nodes (LN) using simultaneous integrated boost (SIB) method. Low risk (LR) patients received 69.4 Gy to the prostate only in 29 fractions. The intermediate (IR) and high risk (HR) patients received 72 Gy to the prostate, 54 Gy to the proximal 1 cm SV, and 50.4 Gy to the pelvic LN when risk of LN involvement >15% by Roach formula. Treatment was given in 30 fractions using intraprostatic fiducials and daily image guidance. PTV expansion for prostate and SV was 0.3 mm posteriorly and 0.7 cm in all other directions. The IR and HR patients received androgen deprivation therapy (3 years for HR patients, and 6 months for IR patients). Acute and late genitourinary (GU) and gastrointestinal (GI) toxicity were prospectively evaluated according to CTCAE v3.0. Results: 55 men (29 African American and 26 white) were enrolled on trial with 20% LR, 41% IR and 39% HR disease (NCCN criteria). The median age was 55 with median follow-up time of 37.9 months. 26 patients received pelvic nodal SIB-IMRT. Toxicity is reported in the table. The biochemical control rate for the cohort was 91% at 3 years. Patients with pelvic LN IMRT experienced grade 2+ acute GI toxicity 38% vs 21% in the non-nodal IMRT group. (p= 0.25 by chi-square test). Conclusions: Hypofractionated SIB-IMRT can be delivered safely. Late grade III GI and GU toxicity for our cohort were 0% and 3.6% respectively. Our prospective trial shows acceptable toxicity with moderate hypofractionation in treating prostate cancer while maintaining good PSA control. Clinical trial information: NCT01117935. [Table: see text]

Patient-reported outcomes after electron radiation treatment for early-stage palmar and plantar fibromatosis

PURPOSE

Palmar and plantar fibromatosis (PPF) is a progressive connective tissue disorder of the hand/foot that often leads to debilitating functional impairment. In Europe, orthovoltage radiation therapy (RT) has been demonstrated to prevent local disease progression for up to 80% of patients with early-stage PPF. There are limited data reporting outcomes for populations outside of Europe or using electron RT.

METHODS AND MATERIALS

Between 2008 and 2013, 44 early-stage PPF cases received RT. RT fields involved clinically defined targets encompassing involved areas (skin changes, cords, nodules) with at least 1.5-cm margins. En face electrons (6-12 MeV) and bolus (0.5-1 cm) were selected individually. Outcomes are reported for patients who participated in an institutional review board-approved standardized questionnaire and chart review.

RESULTS

Thirty-three patients received 66 treatments (45 hands/15 feet and 6 reirradiations). Most frequent dose schemes were 21 Gy (3 Gy in 7 fractions) and 30 Gy (3 Gy in 10 fractions with 6- to 8-week breaks after 15 Gy). Median time to follow-up survey was 31 months. Disease progression at any location within or outside the RT treatment field occurred in 20 of 33 patients (61%). Fourteen of 60 sites (23%) developed in-field progression, but 4 sites were successfully reirradiated with final local control in 50 of 60 sites (83%). RT improved pretreatment symptoms of pain with strain at 30 of 37 sites (81%) and itch/burn sensations at 17 of 21 sites (81%). There were no reported grade ≥2 late toxicities even with reirradiation. Patient reported overall success with treatment was 31 of 33 patients (94%).

CONCLUSION

PPF is a progressive disease. En face electron RT is an effective therapy that stabilizes or improves symptoms in the majority of patients. Reirradiation can be considered as a treatment option for in-field progression. Patients report minimal toxicity and a high rate of satisfaction with treatment.

Estimation of optimal b-value sets for obtaining apparent diffusion coefficient free from perfusion in non-small cell lung cancer

The purpose of this study was to determine optimal sets of b-values in diffusion-weighted MRI (DW-MRI) for obtaining monoexponential apparent diffusion coefficient (ADC) close to perfusion-insensitive intravoxel incoherent motion (IVIM) model ADC (ADCIVIM) in non-small cell lung cancer. Ten subjects had 40 DW-MRI scans before and during radiotherapy in a 1.5 T MRI scanner. Respiratory triggering was applied to the echo-planar DW-MRI with TR ≈ 4500 ms, TE  =  74 ms, eight b-values of 0-1000 μs μm(-2), pixel size  =  1.98 × 1.98 mm(2), slice thickness  =  6 mm, interslice gap  =  1.2 mm, 7 axial slices and total acquisition time ≈6 min. One or more DW-MRI scans together covered the whole tumour volume. Monoexponential model ADC values using various b-value sets were compared to reference-standard ADCIVIM values using all eight b-values. Intra-scan coefficient of variation (CV) of active tumour volumes was computed to compare the relative noise in ADC maps. ADC values for one pre-treatment DW-MRI scan of each of the 10 subjects were computed using b-value pairs from DW-MRI images synthesized for b-values of 0-2000 μs μm(-2) from the estimated IVIM parametric maps and corrupted by various Rician noise levels. The square root of mean of squared error percentage (RMSE) of the ADC value relative to the corresponding ADCIVIM for the tumour volume of the scan was computed. Monoexponential ADC values for the b-value sets of 250 and 1000; 250, 500 and 1000; 250, 650 and 1000; 250, 800 and 1000; and 250-1000 μs μm(-2) were not significantly different from ADCIVIM values (p > 0.05, paired t-test). Mean error in ADC values for these sets relative to ADCIVIM were within 3.5%. Intra-scan CVs for these sets were comparable to that for ADCIVIM. The monoexponential ADC values for other sets-0-1000; 50-1000; 100-1000; 500-1000; and 250 and 800 μs μm(-2) were significantly different from the ADCIVIM values. From Rician noise simulation using b-value pairs, there was a wide range of acceptable b-value pairs giving small RMSE of ADC values relative to ADCIVIM. The pairs for small RMSE had lower b-values as the noise level increased. ADC values of a two b-value set-250 and 1000 μs μm(-2), and all three b-value sets with 250, 1000 μs μm(-2) and an intermediate value approached ADCIVIM, with relative noise comparable to that of ADCIVIM. These sets may be used in lung tumours using comparatively short scan and post-processing times. Rician noise simulation suggested that the b-values in the vicinity of these experimental best b-values can be used with error within an acceptable limit. It also suggested that the optimal sets will have lower b-values as the noise level becomes higher.

Prolactin-immunoglobulin G complexes from human serum act as costimulatory ligands causing proliferation of malignant B lymphocytes

Several lines of evidence indicate that immunoglobulin-bound prolactin found in human serum is not a conventional complex between an anti-prolactin antibody and prolactin but a different type of association of prolactin with the Fab portion of IgG heavy chains. The complex of prolactin with IgG was purified from serum by anti-human prolactin affinity chromatography and was shown to contain close to 1 mole of N epsilon-(gamma-glutamyl)lysine crosslinks per mole of complex, a characteristic feature in structures crosslinked by transglutaminase. Interestingly, the complex caused a proliferation of cells from a subset of patients with chronic lymphocytic leukemia, while it was inactive in a cell proliferation prolactin bioassay. By contrast, human prolactin stimulated the proliferation of cells in the bioassay but had no effect on the complex-responsive cells from the patients. Competition studies with prolactin and free Fc fragment of IgG demonstrated a necessity for engaging both the prolactin and the immunoglobulin receptors for proliferation. More importantly, competition for the growth response by free prolactin and IgG suggests both possible reasons for the slow growth of this neoplasm as well as avenues for control of the disease.