Randomized, Double-Blind Phase III Study of Pazopanib Versus Placebo in Patients With Metastatic Renal Cell Carcinoma Who Have No Evidence of Disease After Metastasectomy: ECOG-ACRIN E2810

PURPOSE

Patients with no evidence of disease (NED) after metastasectomy for renal cell carcinoma are at high risk of recurrence. Pazopanib is an inhibitor of vascular endothelial growth factor receptor and other kinases that improves progression-free survival in patients with metastatic RCC (mRCC). We conducted a randomized, double-blind, placebo-controlled multicenter study to test whether pazopanib would improve disease-free survival (DFS) in patients with mRCC rendered NED after metastasectomy.

PATIENTS AND METHODS

Patients with NED after metastasectomy were randomly assigned 1:1 to receive pazopanib 800 mg once daily versus placebo for 52 weeks. The study was designed to observe an improvement in DFS from 25% to 45% with pazopanib at 3 years, corresponding to 42% reduction in the DFS event rate.

RESULTS

From August 2012 to July 2017, 129 patients were enrolled. The study was unblinded after 83 DFS events (92% information). The study did not meet its primary end point. An updated analysis at 60.5-month median follow-up from random assignment (95% CI, 59.3 to 71.0) showed that the 3-year DFS was 27.4% (95% CI, 17.9 to 41.7) for pazopanib and 21.9% (95% CI, 13.3 to 36.2) for placebo. Hazard ratio (HR) for DFS was 0.90 ([95% CI, 0.60 to 1.34]; Pone-sided = .29) in favor of pazopanib. Three-year overall survival (OS) was 81.9% (95% CI, 72.7 to 92.2) for pazopanib and 91.4% (95% CI, 84.4 to 98.9) for placebo. The HR for OS was 2.55 (95% CI, 1.23 to 5.27) in favor of placebo (Ptwo-sided = .012). Health-related quality-of-life measures deteriorated in the pazopanib group during the treatment period.

CONCLUSION

Pazopanib did not improve DFS as the primary end point compared with blinded placebo in patients with mRCC with NED after metastasectomy. In addition, there was a concerning trend favoring placebo in OS.

Systemic Therapy Update on 177Lutetium-PSMA-617 for Metastatic Castration-Resistant Prostate Cancer: ASCO Guideline Rapid Recommendation Update

ASCO Rapid Recommendation Updates highlight revisions to select ASCO guideline recommendations as a response to the emergence of new and practice-changing data. The rapid updates are supported by an evidence review and follow the guideline development processes outlined in the ASCO Guideline Methodology Manual. The goal of these articles is to disseminate updated recommendations, in a timely manner, to better inform health practitioners and the public on the best available cancer care options. Guidelines and updates are not intended to substitute for independent professional judgment of the treating provider and do not account for individual variation among patients. See appendix for disclaimers and other important information (Appendix 1 and Appendix 2, online only).

Systemic Therapy Update on 177Lutetium-PSMA-617 for Metastatic Castration-Resistant Prostate Cancer: ASCO Rapid Recommendation

ASCO Rapid Recommendations Updates highlight revisions to select ASCO guideline recommendations as a response to the emergence of new and practice-changing data. The rapid updates are supported by an evidence review and follow the guideline development processes outlined in the ASCO Guideline Methodology Manual. The goal of these articles is to disseminate updated recommendations, in a timely manner, to better inform health practitioners and the public on the best available cancer care options.

Evaluation of the Durability of the Immune Humoral Response to COVID-19 Vaccines in Patients With Cancer Undergoing Treatment or Who Received a Stem Cell Transplant

Importance

The durability of the antibody response to COVID-19 vaccines in patients with cancer undergoing treatment or who received a stem cell transplant is unknown and may be associated with infection outcomes.

Objective

To evaluate anti-SARS-CoV-2 spike protein receptor binding domain (anti-RBD) and neutralizing antibody (nAb) responses to COVID-19 vaccines longitudinally over 6 months in patients with cancer undergoing treatment or who received a stem cell transplant (SCT).

Design, Setting, and Participants

In this prospective, observational, longitudinal cross-sectional study of 453 patients with cancer undergoing treatment or who received an SCT at the University of Kansas Cancer Center in Kansas City, blood samples were obtained before 433 patients received a messenger RNA (mRNA) vaccine (BNT162b2 or mRNA-1273), after the first dose of the mRNA vaccine, and 1 month, 3 months, and 6 months after the second dose. Blood samples were also obtained 2, 4, and 7 months after 17 patients received the JNJ-78436735 vaccine. For patients receiving a third dose of an mRNA vaccine, blood samples were obtained 30 days after the third dose.

Interventions

Blood samples and BNT162b2, mRNA-1273, or JNJ-78436735 vaccines.

Main Outcomes and Measures

Geometric mean titers (GMTs) of the anti-RBD; the ratio of GMTs for analysis of demographic, disease, and treatment variables; the percentage of neutralization of anti-RBD antibodies; and the correlation between anti-RBD and nAb responses to the COVID-19 vaccines.

Results

This study enrolled 453 patients (mean [SD] age, 60.4 [13,1] years; 253 [56%] were female). Of 450 patients, 273 (61%) received the BNT162b2 vaccine (Pfizer), 160 (36%) received the mRNA-1273 vaccine (Moderna), and 17 (4%) received the JNJ-7846735 vaccine (Johnson & Johnson). The GMTs of the anti-RBD for all patients were 1.70 (95% CI, 1.04-2.85) before vaccination, 18.65 (95% CI, 10.19-34.11) after the first dose, 470.38 (95% CI, 322.07-686.99) at 1 month after the second dose, 425.80 (95% CI, 322.24-562.64) at 3 months after the second dose, 447.23 (95% CI, 258.53-773.66) at 6 months after the second dose, and 9224.85 (95% CI, 2423.92-35107.55) after the third dose. The rate of threshold neutralization (≥30%) was observed in 203 of 252 patients (80%) 1 month after the second dose and in 135 of 166 patients (81%) 3 months after the second dose. Anti-RBD and nAb were highly correlated (Spearman correlation coefficient, 0.93 [0.92-0.94]; P < .001). Three months after the second dose, anti-RBD titers were lower in male vs female patients (ratio of GMTs, 0.52 [95% CI, 0.34-0.81]), patients older than 65 years vs patients 50 years or younger (ratio of GMTs, 0.38 [95% CI, 0.25-0.57]), and patients with hematologic malignant tumors vs solid tumors (ratio of GMTs, 0.40 [95% CI, 0.20-0.81]).

Conclusions and Relevance

In this cross-sectional study, after 2 doses of an mRNA vaccine, anti-RBD titers peaked at 1 month and remained stable over the next 6 months. Patients older than 65 years of age, male patients, and patients with a hematologic malignant tumor had low antibody titers. Compared with the primary vaccine course, a 20-fold increase in titers from a third dose suggests a brisk B-cell anamnestic response in patients with cancer.

Overall survival based on oncologist density in the United States: A retrospective cohort study

Medically underserved areas (MUA) or health professional shortage areas (HPSA) designations are based on primary care health services availability. These designations are used in recruiting international medical graduates (IMGs) trained in primary care or subspecialty (e.g., oncology) to areas of need. Whether the MUA/HPSA designation correlates with Oncologist Density (OD) and supports IMG oncologists’ recruitment to areas of need is unknown. We evaluated the concordance of OD with the designation of MUAs/HPSAs and evaluated the impact of OD and MUA/HPSA status on overall survival. We conducted a retrospective cohort study of patients diagnosed with hematological malignancies or metastatic solid tumors in 2011 from the Surveillance Epidemiology and End Results (SEER) database. SEER was linked to the American Medical Association Masterfile to calculate OD, defined as the number of oncologists per 100,000 population at the county level. We calculated the proportion of counties with MUA or HPSA designation for each OD category. Overall survival was estimated using the Kaplan-Meier method and compared between the OD category using a log-rank test. We identified 68,699 adult patients with hematologic malignancies or metastatic solid cancers in 609 counties. The proportion of MUA/HPSA designation was similar across counties categorized by OD (93.2%, 95.4%, 90.3%, and 91.7% in counties with <2.9, 2.9–6.5, 6.5–8.4 and >8.4 oncologists per 100K population, p = 0.7). Patients’ median survival in counties with the lowest OD was significantly lower compared to counties with the highest OD (8 vs. 11 months, p<0.0001). The difference remained statistically significant in multivariate and subgroup analysis. MUA/HPSA status was not associated with survival (HR 1.03, 95%CI 0.97–1.09, p = 0.3). MUA/HPSA designation based on primary care services is not concordant with OD. Patients in counties with lower OD correlated with inferior survival. Federal programs designed to recruit physicians in high-need areas should consider the availability of health care services beyond primary care.

Metastatic Plasmacytoid Bladder Cancer Harboring a CDH-1 Mutation and Producing High Levels of CA 19-9. A Case Report and Literature Review

Patient: Female, 64-year-old

Final Diagnosis: Plasmacytoid urothelial carcinoma of the bladder

Symptoms: Nausea • vomiting

Medication:—

Clinical Procedure: Cystoscopy

Specialty: Oncology

Reversal of the Warburg phenomenon in chemoprevention of prostate cancer by sulforaphane

Inhibition of metabolic re-programming represents an attractive approach for prevention of prostate cancer. Studies have implicated increased synthesis of fatty acids or glycolysis in pathogenesis of human prostate cancers. We have shown previously that prostate cancer prevention by sulforaphane (SFN) in Transgenic Adenocarcinoma of Mouse Prostate (TRAMP) model is associated with inhibition of fatty acid metabolism. This study utilized human prostate cancer cell lines (LNCaP, 22Rv1 and PC-3), two different transgenic mouse models (TRAMP and Hi-Myc) and plasma specimens from a clinical study to explore the glycolysis inhibition potential of SFN. We found that SFN treatment: (i) decreased real-time extracellular acidification rate in LNCaP, but not in PC-3 cell line; (ii) significantly downregulated expression of hexokinase II (HKII), pyruvate kinase M2 and/or lactate dehydrogenase A (LDHA) in vitro in cells and in vivo in neoplastic lesions in the prostate of TRAMP and Hi-Myc mice; and (iii) significantly suppressed glycolysis in prostate of Hi-Myc mice as measured by ex vivo1H magnetic resonance spectroscopy. SFN treatment did not decrease glucose uptake or expression of glucose transporters in cells. Overexpression of c-Myc, but not constitutively active Akt, conferred protection against SFN-mediated downregulation of HKII and LDHA protein expression and suppression of lactate levels. Examination of plasma lactate levels in prostate cancer patients following administration of an SFN-rich broccoli sprout extract failed to show declines in its levels. Additional clinical trials are needed to determine whether SFN treatment can decrease lactate production in human prostate tumors.

Thirty-day readmissions due to Venous thromboembolism in patients discharged with syncope

A recent study found that approximately 1 in every 6 patients hospitalized for the 1st episode of syncope had an underlying pulmonary embolism (PE). As current guidelines do not strongly emphasize evaluation for PE in the workup of syncope, we hypothesize that there might be a higher rate of 30-day readmission due to untreated venous thromboembolism (VTE). The objective of this study is to measure the 30-day readmission rate due to VTE and identify predictors of 30-day readmission with VTE among syncope patients. We identified patients admitted with syncope with ICD9 diagnoses code 780.2 in the Nationwide Readmission Database (NRD-2013), Healthcare Cost and Utilization Project (HCUP). The 30-day readmission rate was calculated using methods described by HCUP. Logistic-regression was used to identify predictors of 30-day readmission with VTE. Discharge weights provided by HCUP were used to generate national estimates. In 2013, NRD included 207,339 eligible patients admitted with syncope. The prevalence rates of PE and DVT were 1.1% and 1.4%, respectively. At least one syncope associated condition was present in 60.9% of the patients. Among the patients who were not diagnosed with VTE during index admission for syncope (N = 188,015), 30-day readmission rate with VTE was 0.5% (0.2% with PE and 0.4% with DVT). In conclusion, low prevalence of VTE in patients with syncope and extremely low 30-day readmission rate with VTE argues against missed diagnoses of VTE in index admission for syncope. These results warrant further studies to determine clinical impact of work up for PE in syncope patients without risk factors.

Trends of Inpatient Venous Thromboembolism in United States Before and After the Surgeon General's Call to Action

Venous thromboembolism (VTE) is an important cause of morbidity and mortality in the United States (US). The increasing rates of VTE in the US resulted in the surgeon general issuing a call to action to reduce VTE in 2008. The objective of our study was to analyze the national trends of inpatient VTE in the US from 2004 to 2013 (5 years before and after 2008). We used the dataset National Inpatient Sample, Healthcare Cost and Utilization Project and measured trends of inpatient VTE by annual % change using joinpoint regression software. From 2004 to 2013 the National Inpatient Sample contained data on 78 million hospitalizations (weighted n = 385 million). In these 1.6 million had a diagnosis of VTE (2.0%, weighted n = 7.7 million) including 1.2 million with deep venous thrombosis (DVT) (1.53%, weighted n = 5.9 million) and 588,878 with pulmonary embolism (PE) (0.74%, weighted n = 2.8 million). Joinpoint regression analysis showed that rates of DVT and PE are increasing consistently from 2004 to 2013(1.27% to 1.80% for DVT and 0.52% to 0.92% for PE). The increasing rates of DVT and PE were consistent in all subgroups except few exceptions. In conclusion inpatient VTE rates continue to rise even after 5 years from the surgeon general's a call to action except in certain high-risk patients. Further research is needed to curb the VTE in patients especially among those perceived to be at lower risk of VTE.

A prolonged response to platinum-based therapy in a patient with metastatic urothelial carcinoma harboring a single rearranged and truncated NF2 gene

Tumor genome sequencing has become an invaluable resource in determining targets for new therapies. In this report, we describe the case of a patient with metastatic urothelial carcinoma with sarcomatoid features. Sarcomatoid differentiation is a rare histologic subtype that confers a more aggressive course. The first-line treatment for patients with urothelial carcinoma is platinum-based chemotherapy. Next generation tumor sequencing performed using the FoundationOne assay revealed loss of one NF2 allele and an unbalanced der(22)t(10;22)(p11.22;q12.2) chromosomal rearrangement involving the other NF2 allele, resulting in truncation and predicted loss of function. Fluorescence in situ hybridization (FISH) analysis confirmed the presence of one NF2 signal. NF2 mutations have been found in a variety of cancers and result in activation of the mTOR pathway. As such, the use of mTOR inhibitors, such as everolimus are thought to be particularly effective in the case of NF2 loss. Our patient had a dramatic response to first-line chemotherapy, but unfortunately experienced subsequent progression of his cancer and could not tolerate everolimus. Although our patient's tumor demonstrated unique acquired genetic features including both loss of heterozygosity and truncation of the NF2 locus, he still achieved a meaningful response to platinum-based chemotherapy.

Complete biochemical response after pulmonary metastasectomy in prostate adenocarcinoma

Background

Prostate cancer most commonly metastasizes to bones or lymph nodes, and metastatic prostate cancer is suggestive of disseminated disease. Metastatic disease is usually not amenable to surgery.

Case presentation

The current report presents a unique case of in which the excision of a solitary pulmonary metastasis resulted in undetectable prostate-specific antigen.

Conclusion

This case and others suggest metastasectomy could be considered in cases with solitary metastasis, and physicians should have a careful discussion regarding risks and possible benefits from surgical excision.

Immunotherapy in genitourinary malignancies

Treatment of cancer patients involves a multidisciplinary approach including surgery, radiotherapy, and chemotherapy. Traditionally, patients with metastatic disease are treated with combination chemotherapies or targeted agents. These cytotoxic agents have good response rates and achieve palliation; however, complete responses are rarely seen. The field of cancer immunology has made rapid advances in the past 20 years. Recently, a number of agents and vaccines, which modulate the immune system to allow it to detect and target cancer cells, are being developed. The benefit of these agents is twofold, it enhances the ability the body’s own immune system to fight cancer, thus has a lower incidence of side effects compared to conventional cytotoxic chemotherapy. Secondly, a small but substantial number of patients with metastatic disease are cured by immunotherapy or achieve durable responses lasting for a number of years. In this article, we review the FDA-approved immunotherapy agents in the field of genitourinary malignancies. We also summarize new immunotherapy agents being evaluated in clinical studies either as single agents or as a combination.

Annual Hospital Volume of High Dose Interleukin-2 and Inpatient Mortality in Melanoma and Renal Cell Carcinoma Patients

BACKGROUND

Immunotherapy using high dose interleukin-2 (HD IL2) in patients with renal cell carcinoma (RCC) and melanoma is associated with severe toxicities. The association between annual hospital volume of HD IL2 and inpatient mortality is not well studied. In this study we aim to quantify the impact of annual hospital volume of HD IL2 on inpatient mortality using National Inpatient Sample (NIS) data.

METHODS

We did a cross-sectional study using NIS, one of the largest inpatient datasets in United States, from 2003 to 2011. Patients with melanoma and RCC receiving HD IL2 were identified by ICD9 procedure code 00.15. The primary outcome was inpatient mortality. Using Joinpoint regression, which detects change in trend of inpatient mortality with change in annual volume, the hospitals were classified in three volume categories (low: 1-40, medium: 41-120, high: >120). Multivariate logistic regression was used to identify predictors of inpatient mortality controlling for confounders.

RESULTS

From 2003 to 2011, 29,532 patients with RCC or melanoma who received HD IL2 were identified, and 124 died during the hospitalization (0.4%). The hospitals with low, medium and high annual volume had significant difference in inpatient mortality (0.83%, 0.29% and 0.13% respectively, p = 0.0003). On multivariate analysis, low volume hospitals were associated with significantly higher odds of inpatient mortality (OR 6.1, 95% CI 1.6-23.2, p = 0.003) as compared to high volume hospitals. Additionally, the hospitals with annual volume of 1-20 had even higher rates (1.31% vs. 0.13%, p<0.0001) and multivariate odds (OR 8.9, 95% CI 2.4-33.2, p = 0.0006) of inpatient mortality as compared to high volume hospitals.

CONCLUSIONS

Lower annual hospital volume of HD IL2 is associated with worse outcomes. Annual hospital volume of 1-40 and 1-20 treatments per year is associated with 6 and 9 times higher odds of inpatient mortality respectively as compared to high volume hospitals. Our findings provide preliminary evidence for a volume-outcome relationship for RCC and melanoma patients undergoing HD IL2 treatment. They support future volume-outcome analyses in relation to other anti-cancer therapies that require special training and expertise.

Improving intermittent androgen deprivation therapy: lessons learned from basic and translational research

Intermittent androgen deprivation therapy (IADT) is an alternative to continuous androgen deprivation therapy (ADT) in prostate cancer patients with nonmetastatic disease. ADT is associated with numerous side effects such as hot flashes, sexual dysfunction, anemia, fatigue, loss of muscle mass, osteoporosis, metabolic syndrome and premature cardiovascular disease. IADT was developed with the intention of improving the quality of life and to delay progression of prostate cancer to castration resistance. The benefits of slightly improved quality of life by IADT compared to ADT were demonstrated in multiple clinical trials. IADT was noted to be noninferior to ADT in patients with biochemical recurrence of prostate cancer but in studies performed in patients with metastatic prostate cancer, the results were inconclusive. Our recent studies suggested that the administration of 5 alpha-reductase inhibitors during the off-cycle of IADT can significantly prolong the survival of mice bearing androgen-sensitive prostate tumors when off-cycle duration was short. This review discusses the survival benefit of 5 alpha-reductase inhibition in IADT in animal models and the potential translation of this finding into clinic.

Broccoli-Derived Sulforaphane and Chemoprevention of Prostate Cancer: From Bench to Bedside

Sulforaphane (SFN) is a metabolic by product of cruciferous vegetables and is the biologically active phytochemical found in high concentrations in broccoli. It has been studied extensively for its anticancer efficacy and the underlying mechanisms using cell culture and preclinical models. The immediate precursor of SFN is glucoraphanin, a glucosinolate which requires metabolic conversion to SFN. SFN and other notable isothiocyanates, including phenethyl isothiocyanate and benzyl isothiocyanate found in various cruciferous vegetables, have also been implicated to have a chemopreventive role for breast, colon and prostate cancer. In-vitro and in-vivo anti-cancer activity of this class of compounds summarizing the past two decades of basic science research has previously been reviewed by us and others. The present review aims to focus specifically on SFN and its chemopreventive and antineoplastic activity against prostate cancer. Particular emphasis in this communication is placed on the current status of clinical research and prospects for future clinical trials with the overall objective to better understand the clinical utility of this promising chemopreventive nutraceutical in the context of mechanisms of prostate carcinogenesis.

5α-Reductase inhibition coupled with short off cycles increases survival in the LNCaP xenograft prostate tumor model on intermittent androgen deprivation therapy

PURPOSE

Intermittent androgen deprivation therapy in patients with prostate specific antigen progression after localized prostate cancer treatment is an alternative to standard continuous androgen deprivation therapy. Intermittent androgen deprivation therapy allows for testosterone recovery during off cycles. This stimulates regrowth and differentiation of the regressed prostate tumor, lessens the side effects of continuous androgen deprivation therapy and potentially prolongs survival. Previously intermittent androgen deprivation therapy coupled with finasteride was shown to prolong survival in animals bearing androgen sensitive prostate tumors when the off cycle duration was not prolonged but rather fixed at 10 to 14 days. Regressed prostate tumor xenografts with testosterone replacement were initially responsive to 5α-reductase inhibition but growth resumed after several days. In shorter off cycles of testosterone recovery 5α-reductase inhibition might maximize tumor growth inhibition during intermittent androgen deprivation therapy and perhaps increase survival.

MATERIALS AND METHODS

We used the LNCaP xenograft tumor model to evaluate the effectiveness of short off cycles of 4 days coupled with 5α-reductase inhibition on survival and tumor regrowth while on intermittent androgen deprivation therapy.

RESULTS

Dutasteride inhibited initial testosterone induced tumor regrowth off cycles 1 and 2, and significantly increased survival.

CONCLUSIONS

These results further support the potential for intermittent androgen deprivation therapy combined with 5α-reductase inhibition to improve survival in patients with prostate cancer when off cycle duration is short or very short.

The potential roles of hepatocyte growth factor (HGF)-MET pathway inhibitors in cancer treatment

MET is located on chromosome 7q31 and is a proto-oncogene that encodes for hepatocyte growth factor (HGF) receptor, a member of the receptor tyrosine kinase (RTK) family. HGF, also known as scatter factor (SF), is the only known ligand for MET. MET is a master regulator of cell growth and division (mitogenesis), mobility (motogenesis), and differentiation (morphogenesis); it plays an important role in normal development and tissue regeneration. The HGF-MET axis is frequently dysregulated in cancer by MET gene amplification, translocation, and mutation, or by MET or HGF protein overexpression. MET dysregulation is associated with an increased propensity for metastatic disease and poor overall prognosis across multiple tumor types. Targeting the dysregulated HGF-MET pathway is an area of active research; a number of monoclonal antibodies to HGF and MET, as well as small molecule inhibitors of MET, are under development. This review summarizes the key biological features of the HGF-MET axis, its dysregulation in cancer, and the therapeutic agents targeting the HGF-MET axis, which are in development.

Targeted inhibition of ATR or CHEK1 reverses radioresistance in oral squamous cell carcinoma cells with distal chromosome arm 11q loss

Oral squamous cell carcinoma (OSCC), a subset of head and neck squamous cell carcinoma (HNSCC), is the eighth most common cancer in the U.S.. Amplification of chromosomal band 11q13 and its association with poor prognosis has been well established in OSCC. The first step in the breakage-fusion-bridge (BFB) cycle leading to 11q13 amplification involves breakage and loss of distal 11q. Distal 11q loss marked by copy number loss of the ATM gene is observed in 25% of all Cancer Genome Atlas (TCGA) tumors, including 48% of HNSCC. We showed previously that copy number loss of distal 11q is associated with decreased sensitivity (increased resistance) to ionizing radiation (IR) in OSCC cell lines. We hypothesized that this radioresistance phenotype associated with ATM copy number loss results from upregulation of the compensatory ATR-CHEK1 pathway, and that knocking down the ATR-CHEK1 pathway increases the sensitivity to IR of OSCC cells with distal 11q loss. Clonogenic survival assays confirmed the association between reduced sensitivity to IR in OSCC cell lines and distal 11q loss. Gene and protein expression studies revealed upregulation of the ATR-CHEK1 pathway and flow cytometry showed G2 M checkpoint arrest after IR treatment of cell lines with distal 11q loss. Targeted knockdown of the ATR-CHEK1 pathway using CHEK1 or ATR siRNA or a CHEK1 small molecule inhibitor (SMI, PF-00477736) resulted in increased sensitivity of the tumor cells to IR. Our results suggest that distal 11q loss is a useful biomarker in OSCC for radioresistance that can be reversed by ATR-CHEK1 pathway inhibition.

Upregulation of the ATR-CHEK1 pathway in oral squamous cell carcinomas

The ATR-CHEK1 pathway is upregulated and overactivated in Ataxia Telangiectasia (AT) cells, which lack functional ATM protein. Loss of ATM in AT confers radiosensitivity, although ATR-CHEK1 pathway overactivation compensates, leads to prolonged G(2) arrest after treatment with ionizing radiation (IR), and partially reverses the radiosensitivity. We observed similar upregulation of the ATR-CHEK1 pathway in a subset of oral squamous cell carcinoma (OSCC) cell lines with ATM loss. In the present study, we report copy number gain, amplification, or translocation of the ATR gene in 8 of 20 OSCC cell lines by FISH; whereas the CHEK1 gene showed copy number loss in 12 of 20 cell lines by FISH. Quantitative PCR showed overexpression of both ATR and CHEK1 in 7 of 11 representative OSCC cell lines. Inhibition of ATR or CHEK1 with their respective siRNAs resulted in increased sensitivity of OSCC cell lines to IR by the colony survival assay. siRNA-mediated ATR or CHEK1 knockdown led to loss of G(2) cell cycle accumulation and an increased sub-G(0) apoptotic cell population by flow cytometric analysis. In conclusion, the ATR-CHEK1 pathway is upregulated in a subset of OSCC with distal 11q loss and loss of the G(1) phase cell cycle checkpoint. The upregulated ATR-CHEK1 pathway appears to protect OSCC cells from mitotic catastrophe by enhancing the G(2) checkpoint. Knockdown of ATR and/or CHEK1 increases the sensitivity of OSCC cells to IR. These findings suggest that inhibition of the upregulated ATR-CHEK1 pathway may enhance the efficacy of ionizing radiation treatment of OSCC.

5α-reductase inhibition suppresses testosterone-induced initial regrowth of regressed xenograft prostate tumors in animal models

Androgen deprivation therapy (ADT) is the standard treatment for patients with prostate-specific antigen progression after treatment for localized prostate cancer. An alternative to continuous ADT is intermittent ADT (IADT), which allows recovery of testosterone during off-cycles to stimulate regrowth and differentiation of the regressed prostate tumor. IADT offers patients a reduction in side effects associated with ADT, improved quality of life, and reduced cost with no difference in overall survival. Our previous studies showed that IADT coupled with 5α-reductase inhibitor (5ARI), which blocks testosterone conversion to DHT could prolong survival of animals bearing androgen-sensitive prostate tumors when off-cycle duration was fixed. To further investigate this clinically relevant observation, we measured the time course of testosterone-induced regrowth of regressed LuCaP35 and LNCaP xenograft tumors in the presence or absence of a 5ARI. 5α-Reductase inhibitors suppressed the initial regrowth of regressed prostate tumors. However, tumors resumed growth and were no longer responsive to 5α-reductase inhibition several days after testosterone replacement. This finding was substantiated by bromodeoxyuridine and Ki67 staining of LuCaP35 tumors, which showed inhibition of prostate tumor cell proliferation by 5ARI on day 2, but not day 14, after testosterone replacement. 5α-Reductase inhibitors also suppressed testosterone-stimulated proliferation of LNCaP cells precultured in androgen-free media, suggesting that blocking testosterone conversion to DHT can inhibit prostate tumor cell proliferation via an intracrine mechanism. These results suggest that short off-cycle coupled with 5α-reductase inhibition could maximize suppression of prostate tumor growth and, thus, improve potential survival benefit achieved in combination with IADT.

Abstract 2378: Upregulation of the ATR/CHK1 pathway and decreased therapeutic sensitivity in upper aerodigestive cancer cell lines with distal 11q loss

Gemcitabine, a pyrimidine analog/antimetabolite, is commonly used to treat breast, lung, head and neck, pancreatic, ovarian, biliary, urinary bladder, and cervical carcinomas. Gemcitabine inhibits DNA synthesis by direct inhibition of ribonucleotide reductase by its metabolite, gemcitabine diphosphate, and the incorporation of its active form, gemcitabine triphosphate into the elongating DNA strand, resulting in chain termination. Gemcitabine-induced DNA damage leads to activation of the ATR/CHK1 pathway and S-phase cell cycle arrest. Our previous studies showed that carcinoma cells with our biomarker (distal 11q loss) overexpress ATR and CHK1, resulting in decreased sensitivity to ionizing radiation in biomarker-positive head and neck squamous cell carcinoma (HNSCC) and non-small cell lung carcinoma (NSCLC) cell lines. Several studies in the literature have shown that inhibition of CHK1 increases the sensitivity of tumor cell lines to replication inhibitors, including gemcitabine. In pancreatic cancer cell lines, small molecule inhibitor (SMI)-mediated disruption of CHK1 signaling has been reported to potentiate the cytotoxic effect of gemcitabine. Based on the literature and our previous findings, we now report that biomarker-positive HNSCC and NSCLC cell lines also show ATR/CHK1 upregulation and decreased sensitivity to gemcitabine, Further, we observed that siRNA knockdown of the ATR/CHK1 pathway and SMI inhibition of CHK1 signaling in HNSCC and NSCLC cell lines increase their sensitivity to treatment with gemcitabine. Our previous results showed increased efficacy of ionizing radiation combined with CHK1 inhibition in biomarker-positive cell lines; our new results show increased efficacy of gemcitabine combined with CHK1 inhibition in biomarker-positive HNSCC and NSCLC cell lines. These results provide further support for combining CHK1-targeted therapy with standard therapy in conjunction with an appropriate companion diagnostic biomarker, like distal 11q loss. As is the case with other targeted therapies, biomarker-based selection of the right drug for the right patient appears to increase therapeutic efficacy.

Citation Format: Madhav Sankunny, Rahul A. Parikh, Susanne M. Gollin. Upregulation of the ATR/CHK1 pathway and decreased therapeutic sensitivity in upper aerodigestive cancer cell lines with distal 11q loss. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2378. doi:10.1158/1538-7445.AM2013-2378

Abstract 3113: Effects of an up-regulated ATR-CHEK1 pathway in head and neck squamous cell carcinomas

Background: The ATR-CHEK1 pathway is upregulated in a subset of head and neck squamous cell carcinoma (HNSCC) cell lines with loss of the G1 cell cycle checkpoint. We hypothesized that the upregulated ATR-CHEK1 pathway protects HNSCC from mitotic catastrophe (cell death) by enhancing the G2M phase checkpoint and that inhibition of this pathway may sensitize HNSCC to DNA damaging agents. Methods and Results: In HNSCC, we observed gain, amplification or translocation of the ATR gene in 8 of 20 cell lines studied; whereas the CHEK1 gene is partially lost in 12 of 20 cell lines. ATR and CHEK1 FISH in paraffin sections of primary head and neck squamous cell carcinomas confirmed our findings in HNSCC cell lines. We observed that both ATR and CHEK1 are overexpressed by quantitative PCR in five of eight HNSCC cell lines with loss of the G1 cell cycle checkpoint. Inhibition of ATR and CHEK1 with caffeine or specific inhibition with the respective siRNAs results in increased susceptibility of HNSCC to ionizing radiation by clonogenic cell survival assay. siRNA-mediated ATR or CHEK1 knockdown leads to loss of G2M checkpoint accumulation and increased sub-G0 apoptotic population by flow cytometric analysis. The mechanism of cell death after ATR and CHEK1 knockdown is by mitotic catastrophe, as evidenced by increased premature chromatin condensation. Conclusions: The ATR-CHEK1 pathway is up-regulated in a subset of HNSCC with loss of G1 phase cell cycle checkpoint. The up-regulated ATR-CHEK1 pathway protects these HNSCC from mitotic catastrophe by enhancing the G2M phase cell cycle checkpoints and inhibition of ATR and/or CHEK1 increase the sensitivity of the HNSCC to ionizing radiation. We conclude that inhibition of the up-regulated ATR-CHEK1 pathway in HNSCC may potentiate or increase the efficacy of the current therapeutic modalities for HNSCC.

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 3113. doi:1538-7445.AM2012-3113

Abstract 4499: Loss of ATM (distal chromosome 11q) as a prognostic marker in HPV-negative head and neck squamous cell carcinomas

Introduction: HPV-negative head and neck squamous cell carcinomas (HNSCC) represent a subset of head and neck cancers with poor response to treatment and worse prognosis compared to HPV-positive HNSCC. In our prior pre-clinical experiments with HNSCC cell lines, we demonstrated that copy number loss of ATM as a marker for loss of distal chromosome 11q loss leads to defectiveγ-H2AX focus formation, increased chromosomal instability, and reduced sensitivity to ionizing radiation. We hypothesize that in HPV-negative HNSCC, ATM loss is a biomarker for poor outcome. Methods: We performed a single center, retrospective analysis of 42 HNSCC patients to determine if ATM loss is associated with poor overall survival in HPV-negative HNSCC. We performed fluorescence in situ hybridization using probes to cyclin D1 (CCND1) and ATM to assess copy number changes in paraffin sections from HNSCC tumors. Disease-specific survival was defined as time from the date of tissue procurement (surgery or biopsy) until death from disease (HNSCC). Patients who were alive at last follow-up or had died from causes unrelated to their disease were censored. Disease-specific survival by ATM loss status was estimated by the Kaplan-Meier method and tested for a difference by a two-tailed log rank test. Three covariates, age, T stage and N stage were investigated and the effect of ATM loss upon disease-specific survival was assessed with proportional hazards regression by adjusting for these covariates as needed to determine if ATM loss could be considered independently associated with cancer mortality. Results and Conclusions: HPV-negative HNSCC patients with ATM copy number loss have a median disease-specific survival of only 19 months compared to 65 months for patients without ATM loss (log rank p = .0401). We investigated whether the association between ATM loss and disease-specific survival was due to the confounding influence of other clinical variables. Age and T stage were modestly associated with survival, but neither covariate was correlated with ATM loss. We estimated the hazard ratio for ATM loss alone and conditional upon age and T stage was unchanged (.040 alone vs .047 adjusting for age and T stage). Therefore, distal 11q loss, marked by copy number loss of ATM appears to increase the risk of disease-specific mortality independently of age, N stage and T stage. Our results demonstrate that ATM loss in HPV-negative HNSCC may be prognostic of poor outcome and novel therapeutic strategies may be required in this subset of patients. Further studies to elucidate the mechanisms of distal 11q loss and study potential treatment options are underway in our laboratory.

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 4499. doi:1538-7445.AM2012-4499

Distribution and function of polycystin-2 in mouse retinal ganglion cells

The polycystin family of transient receptor potential (TRP) channels form Ca(2+) regulated cation channels with distinct subcellullar localizations and functions. As part of heteromultimeric channels and multi-protein complexes, polycystins control intracellular Ca(2+) signals and more generally the translation of extracellular signals and stimuli to intracellular responses. Polycystin-2 channels have been cloned from retina, but their distribution and function in retinal ganglion cells (RGCs) have not yet been established. In the present study, we determined cellular and subcellular localization as well as functional properties of polycystin-2 channels in RGCs. Polycystin-2 expression and distribution in RGCs was assessed by immunohistochemistry on vertical cryostat section of mouse retina as well as primary cultured mouse RGCs, using fluorescence microscopy. Biophysical and pharmacological properties of polycystin-2 channels isolated from primary cultured RGCs were determined using planar lipid bilayer electrophysiology. We detected polycystin-2 immunoreactivity both in the ganglion cell layer as well as in primary cultured RGCs. Subcellular analysis revealed strong cytosolic localization pattern of polycystin-2. Polycystin-2 channel current was Ca(2+) activated, had a maximum slope conductance of 114 pS, and could be blocked in a dose-dependent manner by increasing concentrations of Mg(2+). The cytosolic localization of polycystin-2 in RGCs is in accordance with its function as intracellular Ca(2+) release channel. We conclude that polycystin-2 forms functional channels in RGCs, of which biophysical and pharmacological properties are similar to polycystin-2 channels reported for other tissues and organisms. Our data suggest a potential role for polycystin-2 in RGC Ca(2+) signaling.

Novel mechanism of increased Ca2+ release following oxidative stress in neuronal cells involves type 2 inositol-1,4,5-trisphosphate receptors

Dysregulation of Ca(2+) signaling following oxidative stress is an important pathophysiological mechanism of many chronic neurodegenerative disorders, including Alzheimer's disease, age-related macular degeneration, glaucomatous and diabetic retinopathies. However, the underlying mechanisms of disturbed intracellular Ca(2+) signaling remain largely unknown. We here describe a novel mechanism for increased intracellular Ca(2+) release following oxidative stress in a neuronal cell line. Using an experimental approach that included quantitative polymerase chain reaction, quantitative immunoblotting, microfluorimetry and the optical imaging of intracellular Ca(2+) release, we show that sub-lethal tert-butyl hydroperoxide-mediated oxidative stress result in a selective up-regulation of type-2 inositol-1,4,5,-trisphophate receptors. This oxidative stress mediated change was detected both at the transcriptional and translational level and functionally resulted in increased Ca(2+) release into the nucleoplasm from the membranes of the nuclear envelope at a given receptor-specific stimulus. Our data describe a novel source of Ca(2+) dysregulation induced by oxidative stress with potential relevance for differential subcellular Ca(2+) signaling specifically within the nucleus and the development of novel neuroprotective strategies in neurodegenerative disorders.

Loss of distal 11q is associated with DNA repair deficiency and reduced sensitivity to ionizing radiation in head and neck squamous cell carcinoma

About 45% of head and neck squamous cell carcinomas (HNSCC) are characterized by amplification of chromosomal band 11q13. This amplification occurs by a breakage-fusion-bridge (BFB) cycle mechanism. The first step in the BFB cycle involves breakage and loss of distal 11q, from FRA11F (11q14.2) to 11qter. Consequently, numerous genes, including three critical genes involved in the DNA damage response pathway, MRE11A, ATM, and H2AFX are lost in the step preceding 11q13 amplification. We hypothesized that this partial loss of genes on distal 11q may lead to a diminished DNA damage response in HNSCC. Characterization of HNSCC using fluorescence in situ hybridization (FISH) revealed concurrent partial loss of MRE11A, ATM, and H2AFX in all four cell lines with 11q13 amplification and in four of seven cell lines without 11q13 amplification. Quantitative microsatellite analysis and loss of heterozygosity studies confirmed the distal 11q loss. FISH evaluation of a small series of HNSCC, ovarian, and breast cancers confirmed the presence of 11q loss in at least 60% of these tumors. All cell lines with distal 11q loss exhibited a diminished DNA damage response, as measured by a decrease in the size and number of gamma-H2AX foci and increased chromosomal instability following treatment with ionizing radiation. In conclusion, loss of distal 11q results in a defective DNA damage response in HNSCC. Distal 11q loss was also unexpectedly associated with reduced sensitivity to ionizing radiation. Although the literature attributes the poor prognosis in HNSCC to 11q13 gene amplification, our results suggest that distal 11q deletions may be an equally significant factor.