Accuracy of surveillance serum squamous cell carcinoma antigen for cervical cancer recurrence after definitive chemoradiation

OBJECTIVE

Recurrence remains a significant clinical problem for patients with cervical cancer, and early detection may improve outcomes. Serum squamous cell carcinoma antigen (SCCA) is a biomarker of prognosis and response to chemoradiotherapy. We hypothesized that elevated serum SCCA during surveillance is sensitive and specific for recurrence.

METHODS

Pre-treatment and follow-up serum SCCA from patients treated with definitive-intent radiotherapy were measured via enzyme-linked immunosorbent assay in a Clinical Laboratory Improvement Amendments (CLIA)-certified laboratory and analyzed retrospectively. Follow-up SCCA was defined as the value closest to recurrence, or as last available for patients without recurrence. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of follow-up SCCA for recurrence was determined for the whole cohort (Cohort 1), for patients with elevated (Cohort 2), and normal pre-treatment SCCA (Cohort 3). Patterns of failure were also evaluated.

RESULTS

Of 227 patients in Cohort 1, 23% experienced recurrence, and 17% died of cervical cancer. Mean follow-up SCCA was 0.9 (±2.5) for patients with no recurrence and 6.0 (±18.7) for patients with recurrence (p=0.02). Sensitivity, specificity, PPV, and NPV of follow-up SCCA for recurrence in Cohort 1 were 38.5%, 97.1%, 80%, and 84.2%, and for patients in Cohort 2 were 54.5%, 95%, 78.3%, and 86.5%, respectively. Four of 86 patients in Cohort 3 had an elevated follow-up SCCA, two of these at the time of recurrence. Elevated pre-treatment SCCA and follow-up SCCA were associated with isolated pelvic recurrence.

CONCLUSIONS

Surveillance serum SCCA has high specificity and NPV for recurrence, and may be of limited utility in patients with normal pre-treatment SCCA.

Rosacea Core Domain Set for Clinical Trials and Practice: A Consensus Statement

Importance

Inconsistent reporting of outcomes in clinical trials of rosacea is impeding and likely preventing accurate data pooling and meta-analyses. There is a need for standardization of outcomes assessed during intervention trials of rosacea.

Objective

To develop a rosacea core outcome set (COS) based on key domains that are globally relevant and applicable to all demographic groups to be used as a minimum list of outcomes for reporting by rosacea clinical trials, and when appropriate, in clinical practice.

Evidence Review

A systematic literature review of rosacea clinical trials was conducted. Discrete outcomes were extracted and augmented through discussions and focus groups with key stakeholders. The initial list of 192 outcomes was refined to identify 50 unique outcomes that were rated through the Delphi process Round 1 by 88 panelists (63 physicians from 17 countries and 25 patients with rosacea in the US) on 9-point Likert scale. Based on feedback, an additional 11 outcomes were added in Round 2. Outcomes deemed to be critical for inclusion (rated 7-9 by ≥70% of both groups) were discussed in consensus meetings. The outcomes deemed to be most important for inclusion by at least 85% of the participants were incorporated into the final core domain set.

Findings

The Delphi process and consensus-building meetings identified a final core set of 8 domains for rosacea clinical trials: ocular signs and symptoms; skin signs of disease; skin symptoms; overall severity; patient satisfaction; quality of life; degree of improvement; and presence and severity of treatment-related adverse events. Recommendations were also made for application in the clinical setting.

Conclusions and Relevance

This core domain set for rosacea research is now available; its adoption by researchers may improve the usefulness of future trials of rosacea therapies by enabling meta-analyses and other comparisons across studies. This core domain set may also be useful in clinical practice.

Centrosome amplification and aneuploidy driven by the HIV-1-induced Vpr•VprBP•Plk4 complex in CD4+ T cells

HIV-1 infection elevates the risk of developing various cancers, including T-cell lymphoma. Whether HIV-1-encoded proteins directly contribute to oncogenesis remains unknown. We observe that approximately 1-5% of CD4+ T cells from the blood of people living with HIV-1 exhibit over-duplicated centrioles, suggesting that centrosome amplification underlies the development of HIV-1-associated cancers by driving aneuploidy. Through affinity purification, biochemical, and cellular analyses, we discover that Vpr, an accessory protein of HIV-1, hijacks the centriole duplication machinery and induces centrosome amplification and aneuploidy. Mechanistically, Vpr forms a cooperative ternary complex with an E3 ligase subunit, VprBP, and polo-like kinase 4 (Plk4). Unexpectedly, however, the complex enhances Plk4's functionality by promoting its relocalization to the procentriole assembly and induces centrosome amplification. Loss of either Vpr's C-terminal 17 residues or VprBP acidic region, the two elements required for binding to Plk4 cryptic polo-box, abrogates Vpr's capacity to induce these events. Furthermore, HIV-1 WT, but not its Vpr mutant, induces multiple centrosomes and aneuploidy in human primary CD4+ T cells. We propose that the Vpr•VprBP•Plk4 complex serves as a molecular link that connects HIV-1 infection to oncogenesis and that inhibiting the Vpr C-terminal motif may reduce the occurrence of HIV-1-associated cancers.

Immunologic and virologic parameters associated with HIV DNA reservoir size in people living with HIV receiving antiretroviral therapy

BACKGROUND

A better understanding of the dynamics of HIV reservoirs in CD4+ T cells of people with HIV (PWH) receiving antiretroviral therapy (ART) is crucial for developing therapies to eradicate the virus.

METHODS

We conducted a study involving 28 aviremic PWH receiving ART with high and low levels of HIV DNA. We analyzed immunologic and virologic parameters and their association with the HIV reservoir size.

RESULTS

The frequency of CD4+ T cells carrying HIV DNA was associated with higher pre-ART plasma viremia, lower pre-ART CD4+ T cell counts, and lower pre-ART CD4/CD8 ratios. During ART, the High group maintained elevated levels of intact HIV proviral DNA, cell-associated HIV RNA, and inducible virion-associated HIV RNA. HIV sequence analysis showed no evidence for preferential accumulation of defective proviruses nor higher frequencies of clonal expansion in the High versus Low group. Phenotypic and functional T-cell analyses did not show enhanced immune-mediated virologic control in the Low versus High group. Of considerable interest, pre-ART innate immunity was significantly higher in the Low versus High group.

CONCLUSIONS

Our data suggest that innate immunity at the time of ART initiation may play an important role in modulating the dynamics and persistence of viral reservoirs in PWH.

Risk factors for hospital-based surgical site infections

Surgical site infections (SSIs) contribute to morbidity and are costly to the healthcare system. To identify factors associated with SSIs. Case-control study analyzing the Nationwide Readmission Database (NRD). We identified 45,445 SSIs. Infection rates were higher in those who were obese (BMI ≥ 30) (OR: 1.39, 95% CI 1.28-1.51), tobacco users (OR: 1.08, 95% CI 1.02-1.15), diagnosed with diabetes (OR: 1.16, 95% CI 1.10-1.22), with Elixhauser Comorbidity Index ≥ 2 (OR: 1.14, 95% CI 1.09-1.20), admitted to hospital for 4-6 days (OR: 1.35, 95% CI 1.29-1.42), in medium-size hospital (OR: 1.15, 95% CI 1.05-1.26), or large-size hospital (OR: 1.43, 95% CI 1.31-1.56). In contrast, patients who were 60-79 years old (OR: 0.78, 95% CI 0.73-0.84), 80 years or older (OR: 0.66, 95% CI 0.59-0.73), female (OR: 0.95, 95% CI 0.91-0.99), underweight (BMI < 18.5) (OR: 0.14, 95% CI 0.03-0.59), in a non-metropolitan hospital (OR: 0.83, 95% CI 0.75-0.91), self-pay (OR: 0.82, 95% CI 0.74-0.91), or covered by Medicare (OR: 0.86, 95% CI 0.80-0.91) had lower odds. Initial data entry to NRD is susceptible to human error. Patients who are obese, use tobacco, have multiple comorbidities, and have long hospital stays in medium-to-large-size hospitals are at risk of SSIs. Conversely, odds of SSIs are lower in females, age ≥ 60, BMI < 18.5, self-pay or Medicare (versus private insurance), or at smaller hospitals. Understanding factors associated with SSIs may help surgeons anticipate complications.

Leonine Facies of Lepromatous Leprosy

This case report describes a man in his 30s presenting with a 3-year history of progressive nodules on his face and forearms and blurry vision in his left eye.

Impact of Monkeypox Virus Infection on Immune Parameters in a Woman With Human Immunodeficiency Virus Receiving Clinically Effective Antiretroviral Therapy

We describe the immunologic and virologic impact of monkeypox (mpox) infection in a woman with human immunodeficiency virus (HIV) whose plasma HIV viremia was suppressed by clinically effective antiretroviral therapy. Extensive phenotypic analyses of B and T cells in peripheral blood and biomarkers in plasma showed significant immunologic perturbations despite the presence of mild mpox disease. Dramatic shifts were noted in the frequencies of total B cells, plasmablasts, and plasmablast immunoglobulin isotypes. Flow cytometric analyses showed a dramatic increase in the frequency of CD38+HLA-DR+ CD8+ T cells after mpox infection. Our data offer guidance for future studies involving mpox infection in affected populations.

Chinese TikTok (Douyin) challenges and body image concerns: a pilot study

BACKGROUND

Social media content on Western platforms promoting thinness, or thinspiration, has been found to negatively affect body image perception of users. Less is known about non-Western social media use and its effects on body image concerns. Chinese TikTok, known as Douyin, is a popular short video platform with 600 million daily active users. Recent trends on Douyin encourage users to demonstrate thinness through participation in 'body challenges'. This paper argues that such content is comparable to thinspiration, however, to date hardly any research has been undertaken on these challenges. Thus, this pilot study aimed to analyse the content of three viral challenges and investigate their impact on Douyin users.

METHODS

Thirty most viewed videos were collected for three challenges (N = 90): the Coin challenge, the A4 Waist challenge, and the Spider leg challenge. Videos were coded for variables relating to thin idealisation, including thin praise, sexualisation and objectification, and analysed through content analytic methods. Video comments (N ≈ 5500) were analysed through thematic analysis, and main themes were identified.

RESULTS

Preliminary findings showed that participants who objectified their bodies to a greater extent expressed more negative body image concerns. In addition, comments on the videos had themes of thin praise, self-comparison, and promotion of dieting behaviours. In particular, videos of the A4 Waist challenge were found to incite more negative self-comparison in viewers.

CONCLUSION

Preliminary findings suggest all three challenges promote the thin ideal and encourage body image concerns. Further research about the broader impact of body challenges is needed.

SCCA1/SERPINB3 suppresses anti-tumor immunity and blunts therapy-induced T cell responses via STAT-dependent chemokine production

Cancer patients with high serum squamous cell carcinoma antigen (SCCA1/SERPINB3) are commonly associated with treatment resistance and poor prognosis. Despite being a clinical biomarker, the modulation of SERPINB3 in tumor immunity is poorly understood. We found positive correlations of SERPINB3 with CXCL1/8, S100A8/A9 and myeloid cell infiltration through RNAseq analysis of human primary cervix tumors. Induction of SERPINB3 resulted in increased CXCL1/8 and S100A8/A9, which promoted monocyte and MDSC migration in vitro. In mouse models, Serpinb3a-tumors showed increased MDSC and TAM infiltration contributing to T cell inhibition and this was further augmented upon radiation. Intratumoral knockdown of Serpinb3a demonstrated tumor growth inhibition and reduced CXCL1, S100A8/A9, MDSC, and M2 macrophage infiltration. These changes led to enhanced cytotoxic T cell function and sensitized tumors to radiotherapy. We further revealed SERPINB3 promoted STAT-dependent suppressive chemokine expression, whereby inhibiting STAT activation by ruxolitinib or siRNA abrogated CXCL1/8 and S100A8/A9 in SERPINB3 cells. Patients with elevated pre-treatment SCCA and high pSTAT3 had increased intratumoral CD11b+ myeloid cell compared to patients with low SCCA and pSTAT3 cohort that had overall improved survival after radiotherapy. These findings provide a preclinical rationale for targeting SERPINB3 in tumors to counteract the immunosuppression and improve response to radiation.

Abstract 2374: Squamous cell carcinoma antigen regulates macrophage polarization, contributing to inhibition of T cell activity in cervical cancer chemo-radiotherapy

Chemoradiation therapy (CRT) is the standard treatment for locally advanced cervical cancer. Anti-tumor T cell response is critical for immunogenic cell death and tumor regression enabled by CRT. Squamous cell carcinoma antigen (SCCA) is highly expressed in cervical tumors and passively released from tumor cells. Patients with elevated serum SCCA often showed radioresistance and recurrence. Despite its prognostic value, little is known about the function of extracellular SCCA. We analyzed SCCA-associated immune landscape using RNAseq from 20 cervical matched tumor biopsy pairs collected prior to (pre-) and 3 weeks into (mid-) CRT. Patients with low pretreatment SCCA (&lt;6 ng/ml, SCCA/L) and high SCCA (≥6ng/ml, SCCA/H) showed decreased CD4/CD8 T cells at mid-CRT, with a more significant decrease in SCCA/H patients. This corresponded to significantly reduced expression of T-cell trafficking chemokine CXCL9/10 during CRT, particularly in SCCA/H patients. Interestingly, granzyme B (GZMB) and interferon-γ (IFNγ), associated with T-cell cytotoxicity, were increased in 6 of the 10 SCCA/L patients, compared to 1 and 2 of the 10 SCCA/H patients with increased GZMB and IFNγ respectively. Another RNAseq cohort of 66 pre-CRT tumor biopsies also showed significantly higher LAG3 and CTLA4 expression in SCCA/H than SCCA/L patients. In vitro stimulation of human PBMC with CD3/28 antibody in the presence of SCCA1 protein resulted in inhibition of T cell proliferation and decreased cytotoxicity. However, when SCCA1 was incubated with purified CD3 T cells, no inhibition in T cell activity was observed, suggesting the involvement of myeloid cells in SCCA1 mediated T cell activity. To investigate the effect of SCCA1 on myeloid cells, we isolated human CD14+ monocytes, incubated with SCCA1, and found improved survival of CD14+ HLADRlo/neg monocytes. THP1 monocytes, possessed polarizing ability, were differentiated into M1/M2 macrophage with the supplement of SCCA1 during the polarization. The result showed that SCCA1 promoted M2 macrophage phenotypes, including increased M2 marker (CD209), PD-L1 expression, M2-associated cytokines (IL10, CCL18), and M2 polarizing signaling (STAT3 phosphorylation and Myc expression). Macrophages isolated from murine tumors with high SCCA1 expression demonstrated increased suppression on T cell activity in co-culture functional assays. Furthermore, tissue microarray from cervical cancer patients showed that high SCCA was associated with increased infiltration of CD11b+ myeloid cells and CD68+ macrophages in tumors. Overall, we concluded that SCCA promoted M2 polarization and macrophage infiltration, which may contribute to T cell exhaustion, leading to poor survival. Thus, therapeutic targeting of extracellular SCCA should be considered to improve treatment outcomes.

Citation Format: Liyun Chen, Victoria Shi, Matthew Inkman, Jin Zhang, Pippa Cosper, Julie K. Schwarz, Stephanie Markovina. Squamous cell carcinoma antigen regulates macrophage polarization, contributing to inhibition of T cell activity in cervical cancer chemo-radiotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2374.

SCCA1/SERPINB3 promotes suppressive immune environment via STAT-dependent chemokine production, blunting the therapy-induced T cell responses

Radiotherapy is a commonly used cancer treatment; however, patients with high serum squamous cell carcinoma antigen (SCCA1/SERPINB3) are associated with resistance and poor prognosis. Despite being a strong clinical biomarker, the modulation of SERPINB3 in tumor immunity is poorly understood. We investigated the microenvironment of SERPINB3 high tumors through RNAseq of primary cervix tumors and found that SERPINB3 was positively correlated with CXCL1/8, S100A8/A9 and myeloid cell infiltration. Induction of SERPINB3 in vitro resulted in increased CXCL1/8 and S100A8/A9 production, and supernatants from SERPINB3-expressing cultures attracted monocytes and MDSCs. In murine tumors, the orthologue mSerpinB3a promoted MDSC, TAM, and M2 macrophage infiltration contributing to an immunosuppressive phenotype, which was further augmented upon radiation. Radiation-enhanced T cell response was muted in SERPINB3 tumors, whereas Treg expansion was observed. A STAT-dependent mechanism was implicated, whereby inhibiting STAT signaling with ruxolitinib abrogated suppressive chemokine production. Patients with elevated pre-treatment serum SCCA and high pSTAT3 had increased intratumoral CD11b+ myeloid cell compared to patients with low SCCA and pSTAT3 cohort that had overall improved cancer specific survival after radiotherapy. These findings provide a preclinical rationale for targeting STAT signaling in tumors with high SERPINB3 to counteract the immunosuppressive microenvironment and improve response to radiation.

Effect of SARS-CoV-2 vaccine booster on HIV reservoirs and immune markers

We investigated effects of the SARV-CoV-2 booster vaccination on HIV reservoir size, immune markers, and host immune responses in PWH receiving ART. Our data suggest that the SARS-CoV-2 booster vaccine is not likely to replenish the persistent HIV reservoir nor provide an immunologic environment to facilitate active HIV expression/replication.

Prognostic implications of NYHA class and NT-proBNP levels in mild heart failure: a PARADIGM-HF analysis

Background

Treatment recommendations for heart failure (HF) with reduced ejection fraction are primarily centered on New York Heart Association (NYHA) classification, such that apparently asymptomatic patients might not be eligible for disease-modifying therapies. NYHA classification, however, may be particularly limited to discriminate mild forms of HF.

Purpose

The present study aimed to determine the relationship between NYHA classification and an objective measure of HF severity (N-terminal pro–B-type natriuretic peptide [NT pro-BNP]), and their association with long-term prognosis in the PARADIGM-HF trial.

Methods

We compared PARADIGM-HF patients classified as NYHA class I, II, and III at randomization (NYHA class IV patients or with unavailable NYHA class were excluded [n=73]). We present kernel density estimation (KDE) plots–a non-parametric way to describe the underlying distribution of a variable–to compare NT-proBNP levels across NYHA classes. Logistic regression and the area under the receiver operating characteristic curve (AUC) were used to assess the ability to predict a patient's NYHA class using NT-proBNP levels. Time-to-event data were calculated with Kaplan–Meier estimates and NYHA class were further stratified by median baseline NT-proBNP (&lt; or ≥1600 pg/ml). The primary outcome was cardiovascular death or first HF hospitalization.

Results

8326 patients were included in this analysis (median age, 64 years; women, 22%; and median left ventricular ejection fraction, 30%). Of 389 patients classified as NYHA class I at randomization, 228 (59%) changed functional class during the first year after randomization. For log-transformed NT-proBNP, KDE overlapped substantially across NYHA classes (Figure 1A). NT-proBNP levels were a poor predictor of NYHA classification: for NYHA class I vs. II, AUC (95% confidence interval [CI]) was 0.51 (0.48–0.54); for NHYA I vs. III, 0.57 (0.54–0.60); and for NYHA II vs. III, 0.56 (0.54–0.57). NYHA class III patients displayed a distinctively higher rate of cardiovascular deaths or first HF hospitalizations (Figure 1B). NYHA class I and II patients revealed lower event rates that were not significantly different (NYHA II vs. I, HR 1.24 [0.97–1.58]). Stratification by NT-proBNP levels identified subgroups with distinctive risk, such that NYHA I patients with high NT-proBNP levels (n=175) had a higher event rate than patients with low NT-proBNP with any NYHA class (Figure 1C).

Conclusion

NYHA class I and II patients overlapped substantially in objective HF measures and long-term prognosis. NYHA classification remains a powerful predictor of cardiovascular events but might be limited to differentiate mild forms of HF, as apparently asymptomatic patients based on physician-defined functional class might become symptomatic within a year and conceal subjects at substantial risk for adverse outcomes.

Funding Acknowledgement

Type of funding sources: None.

A Longitudinal Study of COVID-19 Sequelae and Immunity: Baseline Findings

BACKGROUND

A substantial proportion of persons who develop COVID-19 report persistent symptoms after acute illness. Various pathophysiologic mechanisms have been implicated in the pathogenesis of postacute sequelae of SARS-CoV-2 infection (PASC).

OBJECTIVE

To characterize medical sequelae and persistent symptoms after recovery from COVID-19 in a cohort of disease survivors and controls.

DESIGN

Cohort study. (ClinicalTrials.gov: NCT04411147).

SETTING

National Institutes of Health Clinical Center, Bethesda, Maryland.

PARTICIPANTS

Self-referred adults with laboratory-documented SARS-CoV-2 infection who were at least 6 weeks from symptom onset were enrolled regardless of presence of PASC. A control group comprised persons with no history of COVID-19 or serologic evidence of SARS-CoV-2 infection, recruited regardless of their current health status. Both groups were enrolled over the same period and from the same geographic area.

MEASUREMENTS

All participants had the same evaluations regardless of presence of symptoms, including physical examination, laboratory tests and questionnaires, cognitive function testing, and cardiopulmonary evaluation. A subset also underwent exploratory immunologic and virologic evaluations.

RESULTS

189 persons with laboratory-documented COVID-19 (12% of whom were hospitalized during acute illness) and 120 antibody-negative control participants were enrolled. At enrollment, symptoms consistent with PASC were reported by 55% of the COVID-19 cohort and 13% of control participants. Increased risk for PASC was noted in women and those with a history of anxiety disorder. Participants with findings meeting the definition of PASC reported lower quality of life on standardized testing. Abnormal findings on physical examination and diagnostic testing were uncommon. Neutralizing antibody levels to spike protein were negative in 27% of the unvaccinated COVID-19 cohort and none of the vaccinated COVID-19 cohort. Exploratory studies found no evidence of persistent viral infection, autoimmunity, or abnormal immune activation in participants with PASC.

LIMITATIONS

Most participants with COVID-19 had mild to moderate acute illness that did not require hospitalization. The prevalence of reported PASC was likely overestimated in this cohort because persons with PASC may have been more motivated to enroll. The study did not capture PASC that resolved before enrollment.

CONCLUSION

A high burden of persistent symptoms was observed in persons after COVID-19. Extensive diagnostic evaluation revealed no specific cause of reported symptoms in most cases. Antibody levels were highly variable after COVID-19.

PRIMARY FUNDING SOURCE

Division of Intramural Research, National Institute of Allergy and Infectious Diseases.

Abstract 212: Squamous cell carcinoma antigen counteracts the radiation-induced antitumor response by driving an immune evasion phenotype through STAT signaling

Radiation therapy (RT)-induced immune response shapes the tumor microenvironment, and is recognized as an essential mechanism for anti-tumor effect. RT promotes the release of neoantigens, damage-associated molecular patterns and cytokines leading to cytotoxic T cell infiltration and enhancing immune surveillance. However, RT-induced anti-tumor response is sometimes hampered by inhibitory signals that suppress T cell function and facilitate tumor immune evasion. Squamous cell carcinoma antigen (SERPINB3/SCCA1) is highly expressed in epithelial cancers including cervix, head and neck, lung, and esophagus, and often associated with poor prognosis. We found that overexpressing mSerpinb3a in Lewis lung carcinoma cells (LL2/mB3a) promoted tumor growth compared to LL2 transduced with control vector (LL2/C). Prior to RT, increased MDSCs, TAMs, and Treg cells were observed in LL2/mB3a tumors compared to LL2/C, and is associated with a shorter RT-induced tumor growth delay in LL2/mB3a. The total number of infiltrating T cells was significantly reduced in LL2/mB3a and LL2/C at 2 days post-RT, with recovery by 5 days post-RT. However, CD8+ T remained low in the LL2/mB3a tumors and showed decreased proliferative capacity compared to LL2/C infiltrating T cells. Importantly, while RT improved the functionality in LL2/C-infiltrating T cells, as shown by ex vivo stimulation resulting in increased TNF and INFγ production compared to non-RT LL2/C-infiltrating T cells, the same improvement was not observed in LL2/mB3a-infiltrating T cells. In human T cell in vitro assay, SERPINB3 inhibited T cell activation by suppressing CD69, and CD25 expression, resulting in impaired proliferation capability. Further study on the association between SERPINB3 and immunosuppression showed that LL2/mB3a had increased suppressive chemokine CXCL1 and S100A8/A9 expression compared to LL2/C tumors and RT further enhanced expression of these chemokines in LL2/mB3a tumors. Likewise, human cancer cells overexpressing SERPINB3 also secreted high levels of CXCL1/8 and S100A8/A9. This chemokine induction was found regulated by elevated phosphorylation of STAT1/3 in SERPINB3-expressing cancer cells, while inhibiting STAT signaling by Ruxolitinib significantly suppressed the SERPINB3-dependent chemokine expression. We found that cervical cancer patients with high pre-treatment serum SCCA level (&gt;16.1 ng/ml) and p-STAT3 level is associated with worse outcome with cancer specific survival at 2 years of about 10% compared to patients with serum SCCA &lt;16.1 and low pSTAT3 of 95%. Our findings indicate that SERPINB3 high tumors produce high levels of suppressive chemokines through STAT signaling, leading to MDSCs, macrophages, and Treg infiltration, which dampen T cell functionality and mitigate the effect of radiation therapy.

Citation Format: Liyun Chen, Victoria Shi, Songyan Wang, Rebecca Freeman, Jin Zhang, Pippa Cosper, Catherine Spina, Julie Schwarz, Stephanie Markovina. Squamous cell carcinoma antigen counteracts the radiation-induced antitumor response by driving an immune evasion phenotype through STAT signaling [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 212.

Combination anti-HIV antibodies provide sustained virological suppression

Antiretroviral therapy is highly effective in suppressing human immunodeficiency virus (HIV)1. However, eradication of the virus in individuals with HIV has not been possible to date2. Given that HIV suppression requires life-long antiretroviral therapy, predominantly on a daily basis, there is a need to develop clinically effective alternatives that use long-acting antiviral agents to inhibit viral replication3. Here we report the results of a two-component clinical trial involving the passive transfer of two HIV-specific broadly neutralizing monoclonal antibodies, 3BNC117 and 10-1074. The first component was a randomized, double-blind, placebo-controlled trial that enrolled participants who initiated antiretroviral therapy during the acute/early phase of HIV infection. The second component was an open-label single-arm trial that enrolled individuals with viraemic control who were naive to antiretroviral therapy. Up to 8 infusions of 3BNC117 and 10-1074, administered over a period of 24 weeks, were well tolerated without any serious adverse events related to the infusions. Compared with the placebo, the combination broadly neutralizing monoclonal antibodies maintained complete suppression of plasma viraemia (for up to 43 weeks) after analytical treatment interruption, provided that no antibody-resistant HIV was detected at the baseline in the study participants. Similarly, potent HIV suppression was seen in the antiretroviral-therapy-naive study participants with viraemia carrying sensitive virus at the baseline. Our data demonstrate that combination therapy with broadly neutralizing monoclonal antibodies can provide long-term virological suppression without antiretroviral therapy in individuals with HIV, and our experience offers guidance for future clinical trials involving next-generation antibodies with long half-lives.

High-fat diet prevents the development of autoimmune diabetes in NOD mice

AIMS

Type 1 diabetes (T1D) has a strong genetic predisposition and requires an environmental trigger to initiate the beta-cell autoimmune destruction. The rate of childhood obesity has risen in parallel to the proportion of T1D, suggesting high-fat diet (HFD)/obesity as potential environmental triggers for autoimmune diabetes. To explore this, non-obese diabetic (NOD) mice were subjected to HFD and monitored for the development of diabetes, insulitis and beta-cell stress.

MATERIALS AND METHODS

Four-week-old female NOD mice were placed on HFD (HFD-NOD) or standard chow-diet. Blood glucose was monitored weekly up to 40 weeks of age, and glucose- and insulin-tolerance tests performed at 4, 10 and 15 weeks. Pancreata and islets were analysed for insulin secretion, beta-cell mass, inflammation, insulitis and endoplasmic reticulum stress markers. Immune cell levels were measured in islets and spleens. Stool microbiome was analysed at age 4, 8 and 25 weeks.

RESULTS

At early ages, HFD-NOD mice showed a significant increase in body weight, glucose intolerance and insulin resistance; but paradoxically, they were protected from developing diabetes. This was accompanied by increased insulin secretion and beta-cell mass, decreased insulitis, increased splenic T-regulatory cells and altered stool microbiome.

CONCLUSIONS

This study shows that HFD protects NOD mice from autoimmune diabetes and preserves beta-cell mass and function through alterations in gut microbiome, increased T-regulatory cells and decreased insulitis. Further studies into the exact mechanism of HFD-mediated prevention of diabetes in NOD mice could potentially lead to interventions to prevent or delay T1D development in humans.

TIGIT expression on CD8+ T cells correlates with higher cytotoxic capacity

Persistent exposure to antigen leads to T cell exhaustion and immunologic dysfunction. We examined the immune exhaustion markers TIGIT and PD-1 in HIV-infected and healthy individuals and the relationship with cytotoxic CD8 + T lymphocyte (CTL) activity. Frequencies of TIGIT but not PD-1 positively correlated with CTL activity in HIV-aviremic and healthy individuals; however, there was no correlation in HIV-viremic individuals. Transcriptome analyses revealed upregulation of genes associated with antiviral immunity in TIGIT + versus TIGIT -CD8 + T cells. Our data suggest that TIGIT +CD8 + T cells do not necessarily represent a state of immune exhaustion and maintain an intrinsic cytotoxicity in HIV-infected individuals.

Kinetics of Plasma HIV Rebound in the Era of Modern Antiretroviral Therapy

Historical data regarding time to viral rebound following analytical treatment interruption (ATI) have been used to determine therapeutic efficacy in HIV cure trials; however, such data were collected from studies conducted a decade or more ago and included participants receiving older antiretroviral therapy (ART) regimens with infrequent virologic monitoring. We conducted a study of 22 HIV-infected participants receiving modern ART to determine the kinetics of plasma viral rebound following ATI. Our data suggest that modern ART does not alter kinetics of viral rebound when compared to previous regimens and that immunologic interventions may be necessary to achieve ART-free virologic remission. Clinical Trials Registration ClinicaTrials.gov identifier: NCT03225118.

Abstract 2426: SERPINB3 promotes radiation resistance in cervical cancer by inhibiting lysosome-mediated cell death

The purpose of this study was to determine if squamous cell carcinoma antigen (SCCA), also known as SERPINB3, protects cervical cancer cells from ionizing radiation (IR)-induced death, and to determine the mechanism(s) of IR-induced cell death with or without SERPINB3. Cervical cancer remains a leading cause of cancer death in women worldwide despite advances in screening, vaccination and treatment. Recurrence after definitive chemoradiation occurs in up to 30-50% of patients with locally advanced disease. We and others have demonstrated that elevated serum SCCA portends poor prognosis in cervical cancer. In addition, CRISPR-Cas9-mediated knock out of SERPINB3 significantly sensitizes cervical tumor cells to IR in vitro. We hypothesize that SERPINB3 promotes radioresistance by protecting cells against lysosome damage and lysosomal mediated necrosis. Two cervical cancer cell lines with high SERPINB3 expression were edited using CRISPR-Cas9 technology at the SERPINB3 locus resulting in knock out (KO). B3-KO cells were significantly more radiation sensitive compared to control cells at all doses and time points evaluated. Cell death morphology in the B3-KO cells was necrotic, with large cytoplasmic single membraned vesicles, many of which were ruptured, consistent with that seen in lysosome-mediated necrosis. Live-cell time-lapse imaging showed loss of lysosome integrity in the hours leading up to cell death (propidium iodide nuclear staining). Western blot analysis showed low levels of caspase-3 and caspase-7 cleavage only at high doses and late time points after IR, with no evidence of phospho-MLKL or phospo-RIPK3 (markers of necroptosis), or gasdermin-D cleavage (marker of pyroptosis). Necrostatin, ferrostatin, liproxstatin and YVAD-Cho had little to no effect on cell death following IR, while pan-caspase inhibitors decreased IR-induced cell death in both control and B3-KO cells, and E64D decreased IR-induced cell death in B3-KO cells to a greater degree than control cells. Additionally, cervical tumor cell lines that had no detectable expression of SERPINB3 were engineered to expressed high levels of SERPINB3 (B3-wt) or SERPINB3 containing the P14 mutation A351R (B3-P14m), which lacks protease inhibitory function. B3-wt expressing cells displayed increased radiation resistance in clonogenic survival assays and mouse tumor models. Growth rate and radiation response of B3-p14m expressing tumors was similar to vector control. These data suggest that SERPINB3 is an important mediator of radiation response in cervical cancer and protects cells by inhibiting cysteine protease-dependent cell death, likely via lysosome-mediated necrosis. These findings support SERPINB3 as a potential target for novel radiosensitizing therapies.

Citation Format: Songyan Wang, Clifford Luke, Victoria Shi, Perry Grigsby, Gary Silverman, Stephanie Markovina. SERPINB3 promotes radiation resistance in cervical cancer by inhibiting lysosome-mediated cell death [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 2426.

Glycan-dependent HIV-specific neutralizing antibodies bind to cells of uninfected individuals

A number of highly potent and broadly neutralizing antibodies (bNAbs) against the human immunodeficiency virus (HIV) have recently been shown to prevent transmission of the virus, suppress viral replication, and delay plasma viral rebound following discontinuation of antiretroviral therapy in animal models and infected humans. However, the degree and extent to which such bNAbs interact with primary lymphocytes have not been fully delineated. Here, we show that certain glycan-dependent bNAbs, such as PGT121 and PGT151, bind to B, activated T, and natural killer (NK) cells of HIV-infected and -uninfected individuals. Binding of these bNAbs, particularly PGT121 and PGT151, to activated CD4+ and CD8+ T cells was mediated by complex-type glycans and was abrogated by enzymatic inhibition of N-linked glycosylation. In addition, a short-term incubation of PGT151 and primary NK cells led to degranulation and cellular death. Our data suggest that the propensity of certain bNAbs to bind uninfected/bystander cells has the potential for unexpected outcomes in passive-transfer studies and underscore the importance of antibody screening against primary lymphocytes.

An open-label phase 1 clinical trial of the anti-α4β7 monoclonal antibody vedolizumab in HIV-infected individuals

Despite the substantial clinical benefits of antiretroviral therapy (ART), complete eradication of HIV has not been possible. The gastrointestinal tract and associated lymphoid tissues may play an important role in the pathogenesis of HIV infection. The integrin α₄β₇ facilitates homing of T lymphocytes to the gut by binding to the mucosal addressin cell adhesion molecule-1 (MAdCAM-1) expressed on venules in gut-associated lymphoid tissue. CD4⁺ T cells with increased expression of α₄β₇ are susceptible to HIV infection and may be key players in subsequent virus dissemination. Data from nonhuman primate models infected with simian immunodeficiency virus (SIV) have suggested that blockade of the α₄β₇/MAdCAM-1 interaction may be effective at preventing SIV infection and may have beneficial effects in animals with established viral infection. To explore whether these findings could be reproduced in HIV-infected individuals after interruption of ART, we conducted an open-label phase 1 clinical trial of vedolizumab, a monoclonal antibody against α₄β₇ integrin. Vedolizumab infusions in 20 HIV-infected individuals were well tolerated with no serious adverse events related to the study drug. After interruption of ART, the median time to meeting protocol criteria to restart therapy was 13 weeks. The median duration of plasma viremia of <400 copies/ml was 5.4 weeks. Only a single subject in the trial experienced prolonged suppression of plasma viremia after interruption of ART. These results suggest that blockade of α₄β₇ may not be an effective strategy for inducing virological remission in HIV-infected individuals after ART interruption.

Impact of Treatment Interruption on HIV Reservoirs and Lymphocyte Subsets in Individuals Who Initiated Antiretroviral Therapy During the Early Phase of Infection

Therapeutic strategies for achieving sustained virologic remission are being explored in human immunodeficiency virus (HIV)-infected individuals who began antiretroviral therapy (ART) during the early phase of infection. In the evaluation of such therapies, clinical protocols should include analytical treatment interruption (ATI); however, the immunologic and virologic impact of ATI in individuals who initiated ART early has not been fully delineated. We demonstrate that ATI causes neither expansion of HIV reservoirs nor immunologic abnormalities following reinitiation of ART. Our findings support the use of ATI to determine whether sustained virologic remission has been achieved in clinical trials of individuals who initiated ART early during HIV infection.

Effect of analytical treatment interruption and reinitiation of antiretroviral therapy on HIV reservoirs and immunologic parameters in infected individuals

Therapeutic strategies aimed at achieving antiretroviral therapy (ART)-free HIV remission in infected individuals are under active investigation. Considering the vast majority of HIV-infected individuals experience plasma viral rebound upon cessation of therapy, clinical trials evaluating the efficacy of curative strategies would likely require inclusion of ART interruption. However, it is unclear what impact short-term analytical treatment interruption (ATI) and subsequent reinitiation of ART have on immunologic and virologic parameters of HIV-infected individuals. Here, we show a significant increase of HIV burden in the CD4⁺ T cells of infected individuals during ATI that was correlated with the level of plasma viral rebound. However, the size of the HIV reservoirs as well as immune parameters, including markers of exhaustion and activation, returned to pre-ATI levels 6–12 months after the study participants resumed ART. Of note, the proportions of near full-length, genome-intact and structurally defective HIV proviral DNA sequences were similar prior to ATI and following reinitiation of ART. In addition, there was no evidence of emergence of antiretroviral drug resistance mutations within intact HIV proviral DNA sequences following reinitiation of ART. These data demonstrate that short-term ATI does not necessarily lead to expansion of the persistent HIV reservoir nor irreparable damages to the immune system in the peripheral blood, warranting the inclusion of ATI in future clinical trials evaluating curative strategies.

While we have made considerable advancements in the treatment of HIV, most infected individuals require life-long treatment to suppress plasma viremia, underscoring the need for the development of additional therapeutic strategies that would allow durable virologic remission in the absence of antiretroviral therapy (ART). While a definitive cure has not yet been identified, the field is moving in a promising direction, and with continued efforts we may arrive at a clinically acceptable alternative to ART. Clinical validation of new treatment options likely requires patients to stop therapy while monitoring for viral rebound, but the effect of treatment interruption and its precise impact on immunologic and virologic parameters in HIV-infected individuals has not been fully delineated. In this work, we measured a significant increase of HIV burden in the CD4⁺ T cells of infected individuals who underwent ATI with subsequent plasma viral rebound. However, the size of the HIV reservoirs as well as immune parameters returned to pre-ATI levels 6–12 months after the participants resumed ART. These data suggest ATI does not lead to expansion of the persistent HIV reservoir nor irreversible damages to the immune system in the peripheral blood.

A randomized controlled safety/efficacy trial of therapeutic vaccination in HIV-infected individuals who initiated antiretroviral therapy early in infection

Despite substantial clinical benefits, complete eradication of HIV has not been possible using antiretroviral therapy (ART) alone. Strategies that can either eliminate persistent viral reservoirs or boost host immunity to prevent rebound of virus from these reservoirs after discontinuation of ART are needed; one possibility is therapeutic vaccination. We report the results of a randomized, placebo-controlled trial of a therapeutic vaccine regimen in patients in whom ART was initiated during the early stage of HIV infection and whose immune system was anticipated to be relatively intact. The objectives of our study were to determine whether the vaccine was safe and could induce an immune response that would maintain suppression of plasma viremia after discontinuation of ART. Vaccinations were well tolerated with no serious adverse events but produced only modest augmentation of existing HIV-specific CD4+ T cell responses, with little augmentation of CD8+ T cell responses. Compared with placebo, the vaccination regimen had no significant effect on the kinetics or magnitude of viral rebound after interruption of ART and no impact on the size of the HIV reservoir in the CD4+ T cell compartment. Notably, 26% of subjects in the placebo arm exhibited sustained suppression of viremia (<400 copies/ml) after treatment interruption, a rate of spontaneous suppression higher than previously reported. Our findings regarding the degree and kinetics of plasma viral rebound after ART interruption have potentially important implications for the design of future trials testing interventions aimed at achieving ART-free control of HIV infection.

Function of Novel Anti-CD19 Chimeric Antigen Receptors with Human Variable Regions Is Affected by Hinge and Transmembrane Domains

Anti-CD19 chimeric antigen receptor (CAR) T cells have caused remissions of B cell malignancies, but problems including cytokine-mediated toxicity and short persistence of CAR T cells in vivo might limit the effectiveness of anti-CD19 CAR T cells. Anti-CD19 CARs that have been tested clinically had single-chain variable fragments (scFvs) derived from murine antibodies. We have designed and constructed novel anti-CD19 CARs containing a scFv with fully human variable regions. T cells expressing these CARs specifically recognized CD19⁺ target cells and carried out functions including degranulation, cytokine release, and proliferation. We compared CARs with CD28 costimulatory moieties along with hinge and transmembrane domains from either the human CD28 molecule or the human CD8α molecule. Compared with T cells expressing CARs with CD28 hinge and transmembrane domains, T cells expressing CARs with CD8α hinge and transmembrane domains produced lower levels of cytokines and exhibited lower levels of activation-induced cell death (AICD). Importantly, CARs with hinge and transmembrane regions from either CD8α or CD28 had similar abilities to eliminate established tumors in mice. In anti-CD19 CARs with CD28 costimulatory moieties, lower levels of inflammatory cytokine production and AICD are potential clinical advantages of CD8α hinge and transmembrane domains over CD28 hinge and transmembrane domains.

Lymphoma Remissions Caused by Anti-CD19 Chimeric Antigen Receptor T Cells Are Associated With High Serum Interleukin-15 Levels

Purpose T cells genetically modified to express chimeric antigen receptors (CARs) targeting CD19 (CAR-19) have potent activity against acute lymphoblastic leukemia, but fewer results supporting treatment of lymphoma with CAR-19 T cells have been published. Patients with lymphoma that is chemotherapy refractory or relapsed after autologous stem-cell transplantation have a grim prognosis, and new treatments for these patients are clearly needed. Chemotherapy administered before adoptive T-cell transfer has been shown to enhance the antimalignancy activity of adoptively transferred T cells. Patients and Methods We treated 22 patients with advanced-stage lymphoma in a clinical trial of CAR-19 T cells preceded by low-dose chemotherapy. Nineteen patients had diffuse large B-cell lymphoma, two patients had follicular lymphoma, and one patient had mantle cell lymphoma. Patients received a single dose of CAR-19 T cells 2 days after a low-dose chemotherapy conditioning regimen of cyclophosphamide plus fludarabine. Results The overall remission rate was 73% with 55% complete remissions and 18% partial remissions. Eleven of 12 complete remissions are ongoing. Fifty-five percent of patients had grade 3 or 4 neurologic toxicities that completely resolved. The low-dose chemotherapy conditioning regimen depleted blood lymphocytes and increased serum interleukin-15 (IL-15). Patients who achieved a remission had a median peak blood CAR⁺ cell level of 98/μL and those who did not achieve a remission had a median peak blood CAR⁺ cell level of 15/μL ( P = .027). High serum IL-15 levels were associated with high peak blood CAR⁺ cell levels ( P = .001) and remissions of lymphoma ( P < .001). Conclusion CAR-19 T cells preceded by low-dose chemotherapy induced remission of advanced-stage lymphoma, and high serum IL-15 levels were associated with the effectiveness of this treatment regimen. CAR-19 T cells will likely become an important treatment for patients with relapsed lymphoma.

Anti-CD19 chimeric antigen receptor T cells preceded by low-dose chemotherapy to induce remissions of advanced lymphoma

LBA3010

Background: T cells genetically-modified to express chimeric antigen receptors (CARs) targeting CD19 have potent activity against a variety of B-cell malignancies. Chemotherapy is administered prior to CAR T cells because depletion of recipient leukocytes enhances the anti-malignancy efficacy of adoptively-transferred T cells; an increase in serum interleukin (IL)-15 is one mechanism for this enhancement. Previously, we (Kochenderfer et al. Journal of Clinical Oncology, 2015) and others have reported patients treated with high-dose chemotherapy prior to anti-CD19 CAR T-cell infusions. This report describes treatment of 22 patients with low-dose conditioning chemotherapy followed by infusion of anti-CD19 CAR T-cells. Methods: Eighteen of 22 treated patients received 300 mg/m2 of cyclophosphamide (cy) daily for 3 days; 4 patients received 500 mg/m2 of cy on the same schedule. All patients received fludarabine 30 mg/m2daily for 3 days on the same days as cy. Patients received a single dose of CAR T cells 2 days after completion of chemotherapy. Blood CAR T cells and serum cytokines were analyzed in all patients. Results: Nineteen patients with various subtypes of diffuse large B-cell lymphoma (DLBCL) had the following responses: 8 CR, 5 PR, 2 SD, and 4 PD. One patient with mantle cell lymphoma obtained a CR. Two patients with follicular lymphoma both obtained CRs. Durations of response currently range from 1 to 20 months; 10 remissions are ongoing. All but 4 patients had either chemotherapy-refractory lymphoma or lymphoma that had relapsed after autologous stem cell transplant. The most prominent toxicities were various neurological toxicities. Other toxicities included fever and hypotension. The median peak blood CAR+ cell level was 47/μL (range 4-1217/μL). Patients obtaining CRs or PRs had higher peak blood CAR+ cell levels than patients experiencing SD or PD. The mean serum IL-15 level was 4 pg/mL before the conditioning chemotherapy and 32 pg/mL after chemotherapy (P < 0.0001). Conclusions: Anti-CD19 CAR T cells can induce remissions of advanced B-cell lymphoma when administered after low-dose chemotherapy. In the near future, CAR T cells will likely be a standard therapy for lymphoma. Clinical trial information: NCT00924326.

Allogeneic T Cells That Express an Anti-CD19 Chimeric Antigen Receptor Induce Remissions of B-Cell Malignancies That Progress After Allogeneic Hematopoietic Stem-Cell Transplantation Without Causing Graft-Versus-Host Disease

PURPOSE

Progressive malignancy is the leading cause of death after allogeneic hematopoietic stem-cell transplantation (alloHSCT). After alloHSCT, B-cell malignancies often are treated with unmanipulated donor lymphocyte infusions (DLIs) from the transplant donor. DLIs frequently are not effective at eradicating malignancy and often cause graft-versus-host disease, a potentially lethal immune response against normal recipient tissues.

METHODS

We conducted a clinical trial of allogeneic T cells genetically engineered to express a chimeric antigen receptor (CAR) targeting the B-cell antigen CD19. Patients with B-cell malignancies that had progressed after alloHSCT received a single infusion of CAR T cells. No chemotherapy or other therapies were administered. The T cells were obtained from each recipient's alloHSCT donor.

RESULTS

Eight of 20 treated patients obtained remission, which included six complete remissions (CRs) and two partial remissions. The response rate was highest for acute lymphoblastic leukemia, with four of five patients obtaining minimal residual disease-negative CR. Responses also occurred in chronic lymphocytic leukemia and lymphoma. The longest ongoing CR was more than 30 months in a patient with chronic lymphocytic leukemia. New-onset acute graft-versus-host disease after CAR T-cell infusion developed in none of the patients. Toxicities included fever, tachycardia, and hypotension. Peak blood CAR T-cell levels were higher in patients who obtained remissions than in those who did not. Programmed cell death protein-1 expression was significantly elevated on CAR T cells after infusion. Presence of blood B cells before CAR T-cell infusion was associated with higher postinfusion CAR T-cell levels.

CONCLUSION

Allogeneic anti-CD19 CAR T cells can effectively treat B-cell malignancies that progress after alloHSCT. The findings point toward a future when antigen-specific T-cell therapies will play a central role in alloHSCT.

Downregulation of HER3 by a novel antisense oligonucleotide, EZN-3920, improves the antitumor activity of EGFR and HER2 tyrosine kinase inhibitors in animal models

Among the four human EGF receptor (HER) family members (EGFR, HER2, HER3, HER4), HER3 is of particular interest as it interacts with HER2 and EGFR via heterodimerization and is a key link to the phosphoinositide 3-kinase (PI3K)/AKT signal transduction axis. Recent studies indicate that HER3 plays a critical role in mediating resistance to agents that target EGFR or HER2. As HER3 lacks significant kinase activity and cannot be inhibited by tyrosine kinase inhibitors, neutralizing antibodies and alternative inhibitors of HER3 have been sought as cancer therapeutics. We describe here a locked nucleic acid (LNA)-based HER3 antisense oligonucleotide, EZN-3920, that specifically downmodulated the expression of HER3, which was associated with growth inhibition. EZN-3920 effectively downmodulated HER3 expression, HER3-driven PI3K/AKT signaling pathway, and growth in tumors derived from BT474M1 breast and HCC827 lung carcinoma cell lines, which overexpress HER2 and EGFR, respectively. Furthermore, when EZN-3920 was coadministered with gefitinib or lapatinib in xenograft tumor models, enhanced antitumor activity compared with the effect of monotherapy was found. The effect was associated with a blockade of induced HER3 mRNA expression caused by lapatinib or gefitinib treatment. Finally, EZN-3920 sustained its antiproliferative effect in trastuzumab-resistant cells and three independently derived gefitinib-resistant cells. Our findings show that downmodulation of HER3 by EZN-3920 leads to the suppression of tumor growth in vitro and in vivo, suggesting that HER3 can be an effective target for the treatment of various cancers that have been activated by HER3 alone or where HER3 activation is associated with EGFR or HER2 expression.

Abstract 5647: Marked sensitivity to mRNA targeting by LNA antisense in tumor cells without a delivery system: Lessons learned and potential translation to the clinic

Background: Unlike siRNAs, single-stranded locked nucleic acid-based antisense oligonucleotides (LNA-ONs) have shown the ability to down regulate mRNAs in vitro and in vivo without any delivery systems such as transfection reagents or liposomes. Hence, LNA-ONs may have significant advantages as a therapeutic compared to siRNAs. Investigation of LNA-ONs that target HIF-1α, survivin, or androgen receptor in cancer patients is ongoing. EZN-3920, a LNA-ON to HER3, down regulates HER3 mRNA over a large concentration range (IC50 = 0.1-10 μM) when multiple cancer cell lines are evaluated (Zhang et al, 2011 Gene Therapy. 18:326). We assess here 1) the generality of down-regulation efficiency using two additional LNA-ONs in multiple cell lines and in cells prepared directly from patient tumors, and 2) the correlation of target down-regulation, growth inhibition, and LNA-ON concentration observed in vitro with in vivo xenograft models. Methods: LNA-ONs were either added to tissue culture media (i.e. no transfection) in vitro or prepared in saline and given IV in vivo. Endpoints were measured by qRT-PCR, MTT, Western Blot analysis, and tumor size. Gene Expression Profiling was performed by Asuragen, Inc. Concentration of LNA-ONs in tissues was measured by LC/MS/MS. Results: LNA-ONs targeting PI3KCA p110α (EZN-4150) or β-catenin (EZN-3892) potently down regulated the target mRNA in 50% of tumor cell lines, thereby confirming the observations made with EZN-3920. Diverse sensitivity of the HER3-directed LNA-ON was also observed in cells derived from over 40 primary tumors. Cell lines that were highly sensitive to LNA-ONs in proliferation assay were also responsive in xenograft tumor models. When anti-tumor efficacy of the LNA-ONs was achieved, the concentration of the drug within the tumor matched the concentration required to effectively down regulate the target in vitro. To understand the mechanisms underlying the resistance to LNA-ONs-mediated down-modulation, several cell lines were made highly resistant to LNA-ONs in vitro by chronic exposure to the agent over several months. Tumors from such cell lines were also resistant to LNA-ONs in xenograft models and can be cross-resistant to multiple LNA-ONs. We are currently identifying common genetic differences in the sensitive and resistant cell. Conclusion: We have shown that LNA-ONs, given without any delivery systems, have broad utility in many cancer cell lines including primary tumor cells in which the intended target is a driver for growth. Furthermore, those cell lines sensitive to LNA-ONs in vitro or ex vivo may help identify tumors in animal models that will be responsive to LNA-ONs. Lastly, mechanistic studies on resistant cells may provide an understanding of the diverse response of tumors to LNA-ONs that could ultimately be used to select patients who might preferentially respond to therapy with LNA-ONs.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5647. doi:1538-7445.AM2012-5647

Reduced expression of the androgen receptor by third generation of antisense shows antitumor activity in models of prostate cancer

The androgen receptor (AR) is a member of a unique class of transcription factors because it contains a ligand-binding domain that, when activated, results in nuclear translocation and the transcriptional activation of genes associated with prostate cancer development. Although androgen deprivation therapies are effective initially for the treatment of prostate cancer, the disease eventually relapses and progresses to castration-resistant prostate cancer (CRPC). Nonetheless, the AR still plays a critical role because late-stage investigational agents that deplete testosterone (abiraterone) or block ligand binding (MDV3100) can still control tumor growth in patients with CRPC. These findings indicate that downmodulation of AR expression may provide a complementary strategy for treating CRPC. In this article, we describe a novel, locked, nucleic acid-based antisense oligonucleotide, designated EZN-4176. When administered as a single agent, EZN-4176 specifically downmodulated AR mRNA and protein, and this was coordinated with inhibition of the growth of both androgen-sensitive and CRPC tumors in vitro as well as in animal models. The effect was specific because no effect on growth was observed with a control antisense oligonucleotide that does not recognize AR mRNA, nor on tumors derived from the PC3, AR-negative, tumor cell line. In addition, EZN-4176 reduced AR luciferase reporter activity in a CRPC model derived from C4-2b cells that were implanted intratibially, indicating that the molecule may control prostate cancer that has metastasized to the bone. These data, together with the continued dependency of CRPC on the AR signaling pathway, justify the ongoing phase I evaluation of EZN-4176 in patients with CRPC.

Abstract 232: Targeting HER3 mRNA by a locked nucleic antisense molecule enhances the antitumor activity of gefitinib in vivo

Background: The HER family consists of four tyrosine kinase receptors designated as EGFR, HER2, HER3 and HER4. HER3 is a unique member that plays a critical role in tumor growth since it 1) can heterodimerize with EGFR or HER2 and is the main link to the downstream PI3K/Akt signaling axis, 2) can mediate resistance to HER1/2-targeted therapeutics, and 3) unlike EGFR or HER2, is not typically overexpressed but still hyperphosphorylated in a variety of tumors. Resistance to the EGFR-tyrosine kinase inhibitors, such as gefitinib, can be associated with EGFR mutations and/or activation of HER3 ultimately leading to activation of the PI3K/AKT axis. We have used an RNA antagonist of HER3, designated EZN-3920, to explore the ability of this compound to inhibit tumor growth and overcome resistance to HER1/2 therapeutics. Methods: Tissue culture cells were treated with EZN-3920, a locked nucleic acid (LNA)-based oligonucleotide complementary to HER3. Compound was either added to tissue culture media (i.e. no transfection) in vitro or prepared in saline and given IV in vivo. Endpoints were measured by qRT-PCR, MTT, Western Blot analysis, Immunohistochemistry, and tumor size. Results: EZN-3920 down modulated HER3 mRNA, protein expression, PI3K/AKT signaling, and inhibited tumor cell proliferation. In vivo, systemic administration of EZN-3920, prepared in saline, resulted in specific down- modulation of HER3 mRNA and protein expression, as well as blockade in PI3K/AKT signaling pathways in NSCLC HCC827 associated with tumor growth inhibition. Similar results were also shown in tumor derived from BT-474-M1 breast carcinoma xenograft models. Interestingly, in the HCC827 tumor model, EZN-3920 at 30 mg/kg (biweekly for 4 weeks, i.v.) and gefitinib at 15 mg/kg (5 times a week for two weeks) completely shrank established tumors while either treatment alone only delayed tumor growth by 40-60%. Conclusions: The studies suggest that down regulation of HER3 by antisense molecule EZN-3920 inhibits human tumor growth in mice. Beyond this, antitumor effects of gefitinib can be enhanced by HER3 down modulation in gefitinib-sensitive tumors. On-going studies will determine if tumors that are resistant to HER1/2 therapeutics will either have enhanced sensitivity to EZN-3920 and/or the compound can restore sensitivity to such agents.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 232. doi:10.1158/1538-7445.AM2011-232