Loren Joseph

Reduced-intensity conditioning with combined haploidentical and cord blood transplantation results in rapid engraftment, low GVHD, and durable remissions.

We conducted a 45 patient prospective study of reduced-intensity conditioning (RIC) and transplantation of unrelated umbilical cord blood (UCB) and CD34(+) stem cells from a haploidentical family member. Median age was 50 years; weight was 80 kg. Fifty-eight percent had active disease. Neutrophil engraftment occurred at 11 days (interquartile range [IQR], 9-15) and platelet engraftment at 19 days (IQR, 15-33). In the majority of patients, early haploidentical engraftment was replaced by durable engraftment of UCB by 100 days, with regular persistence of minor host and/or haplo-hematopoiesis. Percentage of haplochimerism at day 100 correlated with the haplo-CD34 dose (P = .003). Cumulative incidence of acute GVHD (aGVHD) was 25% and chronic GVHD (cGVHD) was 5%. Actuarial survival at 1 year was 55%, progression-free survival (PFS) was 42%, nonrelapse mortality (NRM) was 28%, and relapse was 30%. RIC and haplo-cord transplantation results in fast engraftment of neutrophils and platelets, low incidences of aGVHD and cGVHD, low frequency of delayed opportunistic infections, reduced transfusion requirements, shortened length of hospital stay, and promising long-term outcomes. UCB cell dose had no impact on time to hematopoietic recovery. Therefore, UCB selection can prioritize matching, and better matched donors can be identified rapidly for most patients. This study is registered at http://clinicaltrials.gov as NCI clinical trial no. NCT00943800.

Complete nucleotide and deduced amino acid sequences of human and murine preprocathepsin L. An abundant transcript induced by transformation of fibroblasts.

Transfection of an activated rat oncogene into NIH3T3 fibroblasts leads to transformation and induction of a metastatic phenotype. To identify genes whose activation might mediate these processes, we used a differential screening strategy. A 1.5-kb transcript is induced fiftyfold, constitutes 1% of ras transformed cell messenger RNA (mRNA) and is the most abundantly induced message in these cells. Our sequence data shows that it encodes murine cathepsin L, a potent collagenolytic and elastinolytic lysosomal enzyme. The murine clone was used to isolate human cathepsin L complementary DNA (cDNA) clones. The complete nucleotide and deduced amino acid sequences of human and murine preprocathepsin L are presented and compared to other papain family cysteine proteinases. Northern analysis shows that both human and murine cathepsin L probes hybridize to a 1.5-kb transcript in several tissues, but also to a 4-kb transcript in human kidney. These clones will facilitate studies of the structure, expression, and function of cathepsin L, including its unexpected upregulation in transformation.

miR‐143 and miR‐145 are downregulated in ulcerative colitis: Putative regulators of inflammation and protooncogenes

Background: miR‐143 and miR‐145 are believed to function as colon cancer tumor suppressors, as they inhibit colon cancer cell growth and are downregulated in sporadic colonic tumors. We speculated that miR‐143 and miR‐145 might also be downregulated and contribute to malignant transformation of colonic epithelium in longstanding ulcerative colitis (UC). Methods: Biopsies were obtained 20 cm proximal to the anus from individuals with quiescent UC and from normal controls. RNA and proteins were extracted and measured. miR‐143 and miR‐145 were quantified by real‐time polymerase chain reaction (PCR) and miR‐145 was also assessed by in situ hybridization. Putative targets of these miRNAs, K‐RAS, API5, MEK‐2 (miR‐143), and IRS‐1 (miR‐145) were determined by western blotting. To assess the effects of miR‐143 and miR‐145 on these predicted targets, HCT116 and HCA‐7 colorectal cancer cells were transfected with miR‐143 and miR‐145 and expression levels of these proteins were measured. Results: In UC, miR‐143 and miR‐145 were significantly downregulated 8.3‐fold (3.4–20.1) (P < 0.0001) and 4.3‐fold (2.3–7.8) (P < 0.0001), respectively, compared to normal colon. In contrast, IRS‐1, K‐RAS, API5, and MEK‐2 were upregulated in UC, consistent with their assignments as targets of these miRNAs. Furthermore, transfected miR‐143 and miR‐145 significantly downregulated these proteins in HCT116 or HCA‐7 cells. Conclusions: Compared to normal colonic mucosa, in chronic UC miR‐143 and miR‐145 were significantly downregulated and their predicted targets, IRS‐1, K‐RAS, API5, and MEK‐2 were upregulated. We postulate that loss of these tumor suppressor miRNAs predispose to chronic inflammation and neoplastic progression in IBD. (Inflamm Bowel Dis 2011;)

EGFR Signals Downregulate Tumor Suppressors miR-143 and miR-145 in Western Diet–Promoted Murine Colon Cancer: Role of G1 Regulators

Epidermal growth factor receptors (EGFR) contribute to colonic tumorigenesis in experimental models of colon cancer. We previously showed that EGFR was also required for colonic tumor promotion by Western diet. The goal of this study was to identify EGFR-regulated microRNAs that contribute to diet-promoted colonic tumorigenesis. Murine colonic tumors from Egfrwt and hypomorphic Egfrwa2 mice were screened using micro RNA (miRNA) arrays and miR-143 and miR-145 changes confirmed by Northern, real-time PCR, and in situ analysis. Rodent and human sporadic and ulcerative colitis (UC)-associated colon cancers were examined for miR-143 and miR-145. Effects of EGFR on miR-143 and miR-145 expression were assessed in murine and human colonic cells and their putative targets examined in vitro and in vivo. miR-143 and miR-145 were readily detected in normal colonocytes and comparable in Egfrwt and Egfrwa2 mice. These miRNAs were downregulated in azoxymethane and inflammation-associated colonic tumors from Egfrwt mice but upregulated in Egfrwa2 tumors. They were also reduced in human sporadic and UC colon cancers. EGFR signals suppressed miR-143 and miR-145 in human and murine colonic cells. Transfected miR-143 and miR-145 inhibited HCT116 cell growth in vitro and in vivo and downregulated G1 regulators, K-Ras, MYC, CCND2, cdk6, and E2F3, putative or established targets of these miRNAs. miRNA targets Ras and MYC were increased in colonic tumors from Egfrwt but not Egfrwa2 mice fed a Western diet. EGFR suppresses miR-143 and miR-145 in murine models of colon cancer. Furthermore, Western diet unmasks the tumor suppressor roles of these EGFR-regulated miRNAs. Mol Cancer Res; 9(7); 960–75. ©2011 AACR.

Phase II Study of the Oral MEK Inhibitor Selumetinib in Advanced Acute Myelogenous Leukemia: A University of Chicago Phase II Consortium Trial

Purpose: The clinical relevance of targeting the RAS/RAF/MEK/ERK pathway, activated in 70% to 80% of patients with acute myelogenous leukemia (AML), is unknown. Experimental Design: Selumetinib is an oral small-molecule inhibitor of MAP–ERK kinase (MEK)-1/2. Forty-seven patients with relapsed/refractory AML or 60 years old or more with untreated AML were enrolled on a phase II study. Patients were stratified by FLT3 ITD mutation status. The primary endpoint was response rate (complete, partial, and minor). Leukemia cells were analyzed for extracellular signal—regulated kinase (ERK) and mTOR phosphorylation. Results: Common drug-related toxicities were grade 1–2 diarrhea, fatigue, nausea, vomiting, and skin rash. In the FLT3 wild-type cohort, six of 36 (17%) patients had a response [one partial response, three minor responses, two unconfirmed minor responses (uMR)]. No patient with FLT3 ITD responded. NRAS and KRAS mutations were detected in 7% and 2% of patients, respectively. The sole patient with KRAS mutation had uMR with hematologic improvement in platelets. Baseline p-ERK activation was observed in 85% of patients analyzed but did not correlate with a response. A single-nucleotide polymorphism (SNP) rs3733542 in exon 18 of the KIT gene was detected in significantly higher number of patients with response/stable disease compared with nonresponders (60% vs. 23%; P = 0.027). Conclusions: Selumetinib is associated with modest single-agent antileukemic activity in advanced AML. However, given its favorable toxicity profile, combination with drugs that target other signaling pathways in AML should be considered. The potential association of SNP rs3733542 in exon 18 of the KIT gene with antileukemic activity of selumetinib is intriguing, but will require validation in larger trials. Clin Cancer Res; 20(2); 490–8. ©2013 AACR.

Epidermal growth factor receptor signaling is up-regulated in human colonic aberrant crypt foci.

Aberrant crypt foci (ACF) are collections of abnormal colonic crypts with heterogeneous molecular and pathologic characteristics. Large and dysplastic ACF are putative precursors of colon cancer with neoplastic risk related to increased proliferation. In this study, we examined the role of epidermal growth factor receptor (EGFR) signaling in regulating ACF proliferation. Using magnification chromoendoscopy, we collected large ACF with endoscopic features of dysplasia and separately biopsied adjacent mucosa. Transcript levels were measured by real-time PCR, proteins were assessed by Western blotting, and levels were expressed as fold changes of adjacent mucosa. K-ras and B-Raf mutations were assessed by PCR and Ras activation by the ratio Ras-GTP / (Ras-GTP + Ras-GDP). At the RNA level, 38% of ACF were hyperproliferative, with proliferating cell nuclear antigen (PCNA) mRNA >/=2-fold of adjacent mucosa. Hyperproliferative ACF had significantly increased mRNA levels of EGFR (6.0 +/- 1.7-fold), transforming growth factor-alpha (14.4 +/- 5.0-fold), heparin-binding EGF-like growth factor (4.5 +/- 1.4-fold), cyclin D1 (4.6 +/- 0.7-fold), and cyclooxygenase-2 (COX-2; 9.3 +/- 4.2-fold; P < 0.05). At the protein level, 46% of ACF were hyperproliferative (PCNA, 3.2 +/- 1.2-fold). In hyperproliferative ACF, 44% possessed significant increases in four EGFR signaling components: EGFR (9.5 +/- 1.3-fold), phosphoactive ErbB2 (2.6 +/- 0.4-fold), phosphoactive extracellular signal-regulated kinase (3.7 +/- 1.1-fold), and cyclin D1 (3.4 +/- 0.8-fold; P < 0.05). Ras was activated in 46% of ACF (3.2 +/- 0.4-fold; P < 0.05), but K-ras mutations were present in only 7% of ACF. In contrast to COX-2 mRNA, the protein was not increased in hyperproliferative ACF. In summary, we have shown that ACF with up-regulated PCNA possess increased EGFR signaling components that likely contribute to the enhanced proliferative state of dysplastic-appearing ACF.

Epidermal Growth Factor Receptor Signaling Is Required for Microadenoma Formation in the Mouse Azoxymethane Model of Colonic Carcinogenesis

Colonic carcinogenesis involves the progressive dysregulation of homeostatic mechanisms that control growth. The epidermal growth factor (EGF) receptor (EGFR) regulates colonocyte growth and differentiation and is overexpressed in many human colon cancers. A requirement for EGFR in colonic premalignancy, however, has not been shown. In the current study, we used a specific EGFR antagonist, gefitinib, to investigate this role of the receptor in azoxymethane colonic premalignancy. The azoxymethane model shares many clinical, histologic, and molecular features of human colon cancer. Mice received azoxymethane i.p. (5 mg/kg/wk) or saline for 6 weeks. Animals were also gavaged with gefitinib (10 mg/kg body weight) or vehicle (DMSO) thrice weekly for 18 weeks, a dose schedule that inhibited normal receptor activation by exogenous EGF. Compared with control colonocytes [bromodeoxyuridine (BrdUrd), 2.2+/-1.2%], azoxymethane significantly increased proliferation (BrdUrd, 12.6+/-2.8%), whereas gefitinib inhibited this hyperproliferation (BrdUrd, 6.2+/-4.0%; <0.005). Azoxymethane significantly induced pro-transforming growth factor-alpha (6.4+/-1.3-fold) and increased phospho-(active) EGFR (5.9+/-1.1-fold), phospho-(active) ErbB2 (2.3+/-0.2-fold), and phospho-(active) extracellular signal-regulated kinase (3.3+/-0.4-fold) in premalignant colonocytes. Gefitinib inhibited activations of these kinases by >75% (P<0.05). Gefitinib also significantly reduced the number of large aberrant crypt foci and decreased the incidence of colonic microadenomas from 75% to 33% (P<0.05). Gefitinib concomitantly decreased cell cycle-regulating cyclin D1 and prostanoid biosynthetic enzyme cyclooxygenase-2 in microadenomas, suggesting that these regulators are key targets of EGFR in colonic carcinogenesis. These results show for the first time that EGFR signaling is required for early stages of colonic carcinogenesis. Our findings suggest, moreover, that inhibitors of EGFR might be useful in chemopreventive strategies in individuals at increased risk for colonic malignancies.

Detection and Quantification of BCR-ABL1 Fusion Transcripts by Droplet Digital PCR

Monitoring BCR-ABL1 fusion transcripts by real-time quantitative RT-PCR has become an important clinical test for the management of patients with chronic myeloid leukemia. However, it has some inherent limitations with regard to its lower limit of detection and limit of quantification. Improvement in the lower limit of detection could aid clinicians in selecting candidates for discontinuation of tyrosine kinase inhibitors without relapse. Improvement in the limit of quantification may also avoid unnecessary testing or changes in therapy. Here, we demonstrate the advantages of droplet digital RT-PCR with regard to simplicity, lower limit of detection, and limit of quantification. We expect the advantages of droplet digital RT-PCR will make it the preferred method for quantification of BCR-ABL1 fusion transcripts.

Patterns and kinetics of T-cell chimerism after allo transplant with alemtuzumab-based conditioning: mixed chimerism protects from GVHD, but does not portend disease recurrence

We analyzed the kinetics of CD3 chimerism in 120 consecutive allogeneic hematopoietic cell transplantation (HCT) recipients receiving alemtuzumab-based conditioning. Fifty-two received fludarabine/melphalan, 44 received fludarabine/busulfan, and 24 received clofarabine/melphalan in addition to alemtuzumab. Post-transplant GVHD prophylaxis consisted of tacrolimus. No prophylactic donor lymphocyte infusion or other interventions were used for mixed donor chimerism (MDC). Bone marrow (BM) and/or peripheral blood (PB) samples were obtained at 30 days, 100 days, 180 days, and 1 year following HCT. On Day 30, 15% of assessable patients had MDC in the CD3 compartment. This had increased to 50% by Day 100, and to 63% by Day 180. MDC predicted for a lower risk of acute (p = 0.08) and particularly of chronic GVHD (p = 0.01). MDC was not associated with subsequent relapse or TRM (p = 0.67 and 0.72, respectively). A decline of more than 15% in CD3 chimerism between Day 30 and Day 180 predicted for a 40% risk of subsequent disease recurrence. The observation of MDC after alemtuzumab conditioning does not by itself constitute a risk factor for relapse and should not be used to guide therapeutic intervention. By contrast, declining donor chimerism between Day 30 and Day 180 is associated with a somewhat increased risk of disease recurrence. The high incidence of MDC after alemtuzumab containing conditioning contributes to the low risk of acute and chronic GVHD.

Molecular biology underlying the clinical heterogeneity of prostate cancer: An update

CONTEXT Recent studies have uncovered a number of possible mechanisms by which prostate cancers can become resistant to systemic androgen deprivation, most involving androgen-independent reactivation of the androgen receptor. Genome-wide expression analysis with microarrays has identified a wide array of genes that are differentially expressed in metastatic prostate cancers compared to primary nonrecurrent tumors. Recently, recurrent gene fusions between TMPRSS2 and ETS family genes have been identified and extensively studied for their role in prostatic carcinoma. OBJECTIVE To review the recent developments in the molecular biology of prostate cancer, including those pertaining to the androgen receptor and the newly identified TMPRSS2-related translocations. DATA SOURCES Literature review and personal experience. CONCLUSIONS Prostatic adenocarcinoma is a heterogeneous group of neoplasms with a broad spectrum of pathologic and molecular characteristics and clinical behaviors. Numerous mechanisms contribute to the development of resistance to androgen ablation therapy, resulting in ligand-independent reactivation of the androgen receptor, including amplification, mutation, phosphorylation, and activation of coreceptors. Multiple translocations of members of the ETS oncogene family are present in approximately half of clinically localized prostate cancers. TMPRSS2:ERG gene rearrangement appears to be an early event in prostate cancer and is not observed in benign or hyperplastic prostatic epithelium. Duplication of TMPRSS2:ERG appears to predict a worse prognosis. The relationship between TMPRSS2:ERG gene rearrangement and other morphologic and prognostic parameters of prostate cancer is still unclear.