Diagnostic pitfalls after COVID-19 vaccination in melanoma and breast cancer patients: A case series

Introduction

During the current Coronavirus Disease 2019 (COVID-19) pandemic, significant COVID-19 disease-reducing developments have been made, culminating in the COVID-19 vaccines. However, COVID-19 vaccines may complicate oncological staging and follow-up oncological disease course since they may induce the enlargement of lymph nodes. Consequently, this uncertainty may lead to increased distress.

Presentation of cases

This case series describes seven patients diagnosed with melanoma or breast cancer in whom lymphadenopathy was observed on oncology imaging after COVID-19 vaccination. Four of these patients underwent additional diagnostic testing, all without malignant cells on pathological examination or suspected metastasis on imaging. The remaining patients were re-evaluated, and the lymphadenopathy was interpreted as an adverse outcome of the recent COVID-19 vaccination. In addition, four out of seven patients were vaccinated in the ipsilateral arm relative to the tumor. Abnormal lymph nodes could be observed up to sixty-nine days after COVID-19 vaccination.

Discussion and conclusion

These findings indicate that a COVID-19 vaccination may result in possible false-positive oncological imaging findings in melanoma and breast cancer patients. Moreover, it is advised to administer the vaccine in the contralateral arm of the primary tumor, suspected breast abnormalities, or after the oncologic imaging in melanoma and breast cancer patients.

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Melanoma and breast cancer patients had lymphadenopathy after COVID-19 vaccination.

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Recent COVID-19 vaccination may lead to additional diagnostic testing.

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Lymphadenopathy was observed up to ninety-six days after the COVID-19 vaccination.

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COVID-19 vaccination may result in false-positive oncological imaging findings.

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Vaccinate in the contralateral arm of the primary tumor or after oncological imaging

Increased Levels of Oxidative Damage in Liver Metastases Compared with Corresponding Primary Colorectal Tumors: Association with Molecular Subtype and Prior Treatment

High levels of oxidative stress in disseminated colorectal cancer tumor cells may form a therapeutically exploitable vulnerability. However, it is unclear whether oxidative stress and damage persist in metastases. Therefore, we analyzed markers of oxidative damage in primary colorectal tumors and their corresponding liver metastases. Markers of generic and oxidative DNA damage [phosphorylated histone H2AX (γH2AX) and 8-hydroxy-2'-deoxyguanosine (8-OHdG)] were significantly higher in liver metastases compared with their corresponding primary tumors. Chemotherapy and/or radiotherapy before tumor resection was associated with increased persistent oxidative DNA damage, and this effect was more pronounced in metastases. Immunohistochemistry-based molecular classification into epithelial- and mesenchymal-like molecular subtypes revealed that untreated mesenchymal-like tumors contained lower levels of oxidative DNA damage compared with epithelial-like tumors. Treated mesenchymal-like tumors, but not epithelial-like tumors, showed significantly higher levels of γH2AX and 8-OHdG. Mesenchymal-like tumors expressed significantly lower levels of phosphorylated nuclear factor erythroid 2-related factor 2, a master regulator of the antioxidant response, and nuclear factor erythroid 2-related factor 2-controlled genes. Of interest, a positive 8-OHdG status identified a subgroup of mesenchymal-like metastases with a poor overall survival. An increased capacity to tolerate therapy-induced oxidative damage in mesenchymal-like colorectal cancer may explain, at least in part, the poor responsiveness of these tumors to chemotherapy, which could contribute to the poor survival of this patient subgroup.

Practical and Robust Identification of Molecular Subtypes in Colorectal Cancer by Immunohistochemistry

PURPOSE

Recent transcriptomic analyses have identified four distinct molecular subtypes of colorectal cancer with evident clinical relevance. However, the requirement for sufficient quantities of bulk tumor and difficulties in obtaining high-quality genome-wide transcriptome data from formalin-fixed paraffin-embedded tissue are obstacles toward widespread adoption of this taxonomy. Here, we develop an immunohistochemistry-based classifier to validate the prognostic and predictive value of molecular colorectal cancer subtyping in a multicenter study.

EXPERIMENTAL DESIGN

Tissue microarrays from 1,076 patients with colorectal cancer from four different cohorts were stained for five markers (CDX2, FRMD6, HTR2B, ZEB1, and KER) by immunohistochemistry and assessed for microsatellite instability. An automated classification system was trained on one cohort using quantitative image analysis or semiquantitative pathologist scoring of the cores as input and applied to three independent clinical cohorts.

RESULTS

This classifier demonstrated 87% concordance with the gold-standard transcriptome-based classification. Application to three validation datasets confirmed the poor prognosis of the mesenchymal-like molecular colorectal cancer subtype. In addition, retrospective analysis demonstrated the benefit of adding cetuximab to bevacizumab and chemotherapy in patients with RAS wild-type metastatic cancers of the canonical epithelial-like subtypes.

CONCLUSIONS

This study shows that a practical and robust immunohistochemical assay can be employed to identify molecular colorectal cancer subtypes and uncover subtype-specific therapeutic benefit. Finally, the described tool is available online for rapid classification of colorectal cancer samples, both in the format of an automated image analysis pipeline to score tumor core staining, and as a classifier based on semiquantitative pathology scoring. Clin Cancer Res; 23(2); 387-98. ©2016 AACR.

Identification of the DEAD box RNA helicase DDX3 as a therapeutic target in colorectal cancer

Identifying druggable targets in the Wnt-signaling pathway can optimize colorectal cancer treatment. Recent studies have identified a member of the RNA helicase family DDX3 (DDX3X) as a multilevel activator of Wnt signaling in cells without activating mutations in the Wnt-signaling pathway. In this study, we evaluated whether DDX3 plays a role in the constitutively active Wnt pathway that drives colorectal cancer.

We determined DDX3 expression levels in 303 colorectal cancers by immunohistochemistry. 39% of tumors overexpressed DDX3. High cytoplasmic DDX3 expression correlated with nuclear β-catenin expression, a marker of activated Wnt signaling. Functionally, we validated this finding in vitro and found that inhibition of DDX3 with siRNA resulted in reduced TCF4-reporter activity and lowered the mRNA expression levels of downstream TCF4-regulated genes. In addition, DDX3 knockdown in colorectal cancer cell lines reduced proliferation and caused a G1 arrest, supporting a potential oncogenic role of DDX3 in colorectal cancer.

RK-33 is a small molecule inhibitor designed to bind to the ATP-binding site of DDX3. Treatment of colorectal cancer cell lines and patient-derived 3D cultures with RK-33 inhibited growth and promoted cell death with IC50 values ranging from 2.5 to 8 μM. The highest RK-33 sensitivity was observed in tumors with wild-type APC-status and a mutation in CTNNB1.

Based on these results, we conclude that DDX3 has an oncogenic role in colorectal cancer. Inhibition of DDX3 with the small molecule inhibitor RK-33 causes inhibition of Wnt signaling and may therefore be a promising future treatment strategy for a subset of colorectal cancers.

Mice lacking functional CD95-ligand display reduced proliferation of the intestinal epithelium without gross homeostatic alterations

Homeostasis of the continuously self-renewing intestinal tract involves cell proliferation, migration, differentiation along the crypt-villus-axis and shedding of cells into the gut lumen. CD95-ligand (FAS-ligand, CD95L) is a cytokine that is known for its capacity to induce apoptosis by binding its cognate receptor, CD95 (Fas). More recently, it was discovered that CD95L can also induce other cellular responses, such as proliferation, differentiation and cell migration. CD95L is highly expressed in Paneth cells of the small intestine which are in close contact with intestinal stem cells. This suggests a potential role for CD95L in controlling stem cell function and, possibly, intestinal homeostasis. We analyzed the intestines of mice deficient for functional CD95L (gld) for potential alterations in the diversity of stem-cell-lineages and parameters of intestinal homeostasis. Stem cell diversity was assessed by analyzing methylation patterns of the non-transcribed mMYOD gene. Proliferation was analyzed by BrdU labeling and differentiation was assessed by immunohistochemistry. Of all parameters analyzed, only epithelial cell proliferation was significantly reduced in the small intestines of gld-mice, but not in their colons which lack CD95L expression. We conclude that CD95L has a proliferation-stimulating role during normal turnover of the small intestine, but has a marginal effect on overall intestinal homeostasis.

ABC-Transporter Expression Does Not Correlate with Response to Irinotecan in Patients with Metastatic Colorectal Cancer

BACKGROUND

Active efflux of irinotecan by ATP-binding cassette (ABC)-transporters, in particular ABCB1 and ABCG2, is a well-established drug resistance mechanism in vitro and in pre-clinical mouse models, but its relevance in colorectal cancer (CRC) patients is unknown. Therefore, we assessed the association between ABC-transporter expression and tumour response to irinotecan in patients with metastatic CRC.

METHODS

Tissue microarrays of a large cohort of metastatic CRC patients treated with irinotecan in a prospective study (CAIRO study; n=566) were analysed for expression of ABCB1 and ABCG2 by immunohistochemistry. Kaplan-Meier and Cox proportional hazard regression analyses were performed to assess the association of ABC transporter expression with irinotecan response. Gene expression profiles of 17 paired tumours were used to assess the concordance of ABCB1/ABCG2 expression in primary CRC and corresponding metastases.

RESULTS

The response to irinotecan was not significantly different between primary tumours with positive versus negative expression of ABCB1 (5.8 vs 5.7 months, p=0.696) or ABCG2 (5.7 vs 6.1 months, p=0.811). Multivariate analysis showed neither ABCB1 nor ABCG2 were independent predictors for progression free survival. There was a mediocre to poor concordance between ABC-transporter expression in paired tumours.

CONCLUSION

In metastatic CRC, ABC-transporter expression in the primary tumour does not predict irinotecan response.

Abstract 3570: Identification of the DEAD box RNA helicase DDX3 as a therapeutic target in colorectal cancer

Over 85% of colorectal cancers is driven by aberrations in the Wnt-signaling pathway. Thus, identifying druggable targets in this pathway can be beneficial for optimizing colorectal cancer treatment. Within this context, a member of the RNA helicase gene family, DDX3, has been identified to exhibit oncogenic properties in breast and lung carcinomas as well as medulloblastomas. Notably, recent studies have identified DDX3 as a multilevel activator of Wnt-signaling in both normal and transformed cells without activating mutations in the Wnt signaling pathway. In this study, we evaluated whether DDX3 also plays a role in the constitutionally activated Wnt-signaling that drives colorectal cancer and therefore could be a potential therapeutic target in this cancer type.

To determine if DDX3 is expressed in colorectal cancers, we immunohistochemically stained a cohort of 303 Dutch and German colorectal cancer patients. We found 40.4% of these tumors to overexpress DDX3 in comparison to the surrounding normal tissue. DDX3 expression was found predominantly in the cytoplasm and occasionally in the nucleus. High cytoplasmic DDX3 expression correlated with nuclear Beta-catenin expression, a marker of activated Wnt-signaling. The presence of nuclear DDX3 expression correlated with shorter overall survival (HR = 2.38, 95% CI 1.45-3.93, p < 0.001). Functionally, we validated these findings in vitro and found that inhibition of DDX3 with siRNA resulted in reduced proliferation and a G1-arrest in the HCT116 and HT29 colorectal cancer cell lines. This finding further supports the potential oncogenic role of DDX3 in colorectal cancer.

With respect to targeting DDX3, we developed a small molecule inhibitor of DDX3, referred to as RK-33. RK-33 is designed to bind to the ATP-binding site of DDX3 and abrogate its functional activity. As proof of principle, we demonstrated that RK-33 binds preferentially to DDX3 and not to DDX5 and DDX17, other members of the RNA helicase family. Moreover, RK-33 inhibited the helicase activity in an in vitro assay. Furthermore, treatment of colorectal cancer cell lines and patient derived 3D- tumor cell cultures indicated that RK-33 inhibits growth and promotes cell death with IC-50 values ranging from 2.5 to 8 uM.

To further elucidate the mechanism of RK-33, we studied if inhibition of DDX3 with RK-33 could cause inhibition of Wnt-signaling in colorectal cancer cell lines. Treatment with RK-33 indeed resulted in reduced TCF-reporter activity and lowered the mRNA expression levels of the Wnt-signaling downstream target genes AXIN-2, C-MYC, CCND1 and BIRC5A.

Overall, we conclude that DDX3 has an oncogenic role in colorectal cancer. Inhibition of DDX3 with the small molecule inhibitor RK-33 causes potent inhibition of Wnt-signaling and is a promising future treatment strategy in colorectal cancer.

Citation Format: Marise R. Heerma van Voss, Farhad Vesuna, Kari Trumpi, Justin Brilliant, Liudmila L. Kodach, Folkert H.M. Morsink, G. Johan A. Offerhaus, Horst Buerger, Elsken van der Wall, Paul J. van Diest, Venu Raman. Identification of the DEAD box RNA helicase DDX3 as a therapeutic target in colorectal cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3570. doi:10.1158/1538-7445.AM2015-3570

SIRT1/PGC1α-Dependent Increase in Oxidative Phosphorylation Supports Chemotherapy Resistance of Colon Cancer

PURPOSE

Chemotherapy treatment of metastatic colon cancer ultimately fails due to development of drug resistance. Identification of chemotherapy-induced changes in tumor biology may provide insight into drug resistance mechanisms.

EXPERIMENTAL DESIGN

We studied gene expression differences between groups of liver metastases that were exposed to preoperative chemotherapy or not. Multiple patient-derived colonosphere cultures were used to assess how chemotherapy alters energy metabolism by measuring mitochondrial biomass, oxygen consumption, and lactate production. Genetically manipulated colonosphere-initiated tumors were used to assess how altered energy metabolism affects chemotherapy efficacy.

RESULTS

Gene ontology and pathway enrichment analysis revealed significant upregulation of genes involved in oxidative phosphorylation (OXPHOS) and mitochondrial biogenesis in metastases that were exposed to chemotherapy. This suggested chemotherapy induces a shift in tumor metabolism from glycolysis towards OXPHOS. Indeed, chemotreatment of patient-derived colonosphere cultures resulted in an increase of mitochondrial biomass, increased expression of respiratory chain enzymes, and higher rates of oxygen consumption. This was mediated by the histone deacetylase sirtuin-1 (SIRT1) and its substrate, the transcriptional coactivator PGC1α. Knockdown of SIRT1 or PGC1α prevented chemotherapy-induced OXPHOS and significantly sensitized patient-derived colonospheres as well as tumor xenografts to chemotherapy.

CONCLUSIONS

Chemotherapy of colorectal tumors induces a SIRT1/PGC1α-dependent increase in OXPHOS that promotes tumor survival during treatment. This phenomenon is also observed in chemotherapy-exposed resected liver metastases, strongly suggesting that chemotherapy induces long-lasting changes in tumor metabolism that potentially interfere with drug efficacy. In conclusion, we propose a novel mechanism of chemotherapy resistance that may be clinically relevant and therapeutically exploitable.

Paired image- and FACS-based toxicity assays for high content screening of spheroid-type tumor cell cultures

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Design of a high throughput toxicity assay for spheroid-type tumor cell cultures.

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Cell viability, rather than a proxy thereof, is measured.

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Cell viability is measured on a per-cell, rather than per-well, basis.

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The method can be implemented on standard automated microscopes.

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It provides a low-cost approach for accurate and reproducible toxicity screens.

Novel spheroid-type tumor cell cultures directly isolated from patients’ tumors preserve tumor characteristics better than traditionally grown cell lines. However, such cultures are not generally used for high-throughput toxicity drug screens. In addition, the assays that are commonly used to assess drug-induced toxicity in such screens usually measure a proxy for cell viability such as mitochondrial activity or ATP-content per culture well, rather than actual cell death. This generates considerable assay-dependent differences in the measured toxicity values. To address this problem we developed a robust method that documents drug-induced toxicity on a per-cell, rather than on a per-well basis. The method involves automated drug dispensing followed by paired image- and FACS-based analysis of cell death and cell cycle changes. We show that the two methods generate toxicity data in 96-well format which are highly concordant. By contrast, the concordance of these methods with frequently used well-based assays was generally poor. The reported method can be implemented on standard automated microscopes and provides a low-cost approach for accurate and reproducible high-throughput toxicity screens in spheroid type cell cultures. Furthermore, the high versatility of both the imaging and FACS platforms allows straightforward adaptation of the high-throughput experimental setup to include fluorescence-based measurement of additional cell biological parameters.

Abstract 3351: Survival of colorectal cancer cells following chemotherapy relies on a SIRT1-dependent increase in oxidative phosphorylation

Background: Altered energy metabolism is one of the hallmarks of cancer. Tumor cells reprogram their energy metabolism to meet the demands of uncontrolled cell division. During tumorigenesis the vast majority of cancer cells become highly glycolytic (Warburg effect) accompanied by a decrease in oxidative metabolism. Chemotherapy is likely to affect the energy metabolism of tumor cells, but how specific drugs affect specific metabolic pathways is only beginning to be addressed.

Methods: the effects of cytotoxic agents on energy metabolism were assessed by flow cytometric uptake of Mitotracker®, the ratio of mitochondrial and nuclear DNA on qRT-PCR, western blotting for protein levels of the different complexes of the respiratory chain and oxygen consumption rate by the Seahorse Extracellular Flux Analyzer. Cell death was analyzed by flow cytometric uptake of Propidium Iodide, Nicoletti assay and protein levels of caspases 3 and 8.

Results: Gene expression analysis was performed on 119 resected liver metastases of colorectal tumors. Of all clinical variables tested, neoadjuvant chemotherapy was most prominently associated with changes in gene expression. Gene ontology and pathway analysis tools revealed that many of the chemotherapy-associated genes were involved in the regulation of oxidative phosphorylation (OxPhos). To test whether chemotherapy affects OxPhos patient derived colorectal spheroids were treated with the standard cytotoxic agents oxaliplatin and 5-fluorouracil. Chemotherapy strongly increases mitochondrial load, oxygen consumption rate and mitochondrial ATP synthesis.

In line with these results chemo-treated tumor cells displayed a higher ratio of mitochondrial-to-nuclear DNA and expression of respiratory complex components was strongly increased following chemotherapy. Chemotherapy strongly induced expression of the histone deacetylase SIRT1, which has been implicated in mitochondrial biogenesis. Inhibition (by either nicotinamide, EX-527, Tenovin-6) or knockdown of SIRT1 prevented the chemotherapy-induced increase in oxidative phosphorylation. Moreover, SIRT1 knockdown greatly reduced tumor cell survival and clonogenic capacity following removal of chemotherapy.

Conclusion: Chemotherapy induces an increase in oxidative phosphorylation via SIRT1 and this is required for tumor cell survival following drug removal. Since DNA repair requires ATP, mitochondrial biogenesis may be part of the tumor cell response to DNA-damaging agents. Post-chemotherapy targeting of SIRT1 (or OxPhos enzymes) may be an interesting novel approach to increase chemotherapy efficacy.

Citation Format: Thomas T. Vellinga, Vincent C. de Boer, Tijana Borovski, Kari Trumpi, Szabolcs Fatrai, Onno Kranenburg, Inne H.M. Borel Rinkes, Jeroen Hagendoorn. Survival of colorectal cancer cells following chemotherapy relies on a SIRT1-dependent increase in oxidative phosphorylation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3351. doi:10.1158/1538-7445.AM2014-3351