Use of a real-world synthetic control arm for direct comparison of lisocabtagene maraleucel and conventional therapy in relapsed/refractory large B-cell lymphoma

This study used a real-world population as a synthetic comparator for the single-arm TRANSCEND NHL 001 study (TRANSCEND; NCT02631044) to evaluate the efficacy of lisocabtagene maraleucel (liso-cel) compared with conventional (noncellular) therapies in patients with relapsed/refractory (R/R) large B-cell lymphoma (LBCL). Inclusion and exclusion criteria for the real-world study closely matched the enrollment criteria in TRANSCEND. The analytic comparator cohort was created by matching and balancing observed baseline characteristics of real-world patients with those in TRANSCEND using propensity score methodology. Efficacy outcomes comparing liso-cel- (n = 257) and conventional therapy-treated (n = 257) patients, respectively, significantly favored liso-cel: overall response rate (74% vs 39%; p < 0.0001), complete response rate (50% vs 24%; p < 0.0001), median overall survival (23.5 vs 6.8 months; p < 0.0001), and median progression-free survival (3.5 vs 2.2 months; p < 0.0001). These results demonstrated a statistically significant and clinically meaningful benefit of liso-cel in patients with third- or later-line R/R LBCL relative to conventional therapies.Clinical trial registration: ClinicalTrials.gov identifier: NCT02631044.

Phase 2 results of lisocabtagene maraleucel in Japanese patients with relapsed/refractory aggressive B-cell non-Hodgkin lymphoma

The autologous anti-CD19 chimeric antigen receptor (CAR) T-cell product, lisocabtagene maraleucel (liso-cel), is administered at equal target doses of CD8⁺ and CD4⁺ CAR⁺ T cells. This analysis assessed safety and efficacy of liso-cel in Japanese patients with relapsed or refractory (R/R) aggressive large B-cell lymphoma (LBCL) in Cohort 3 of TRANSCEND WORLD (NCT03484702). Liso-cel (100 × 10⁶ total CAR⁺ T cells) was administered 2-7 days after lymphodepletion. The primary efficacy endpoint was objective response rate (ORR; Lugano 2014 criteria) assessed by an independent review committee. Fourteen patients were enrolled; 10 received liso-cel infusion (median time to liso-cel availability, 23 days) and were evaluable at data cutoff (median follow-up, 12.5 months). Grade ≥ 3 treatment-emergent adverse events were neutropenia (90%), leukopenia (80%), anemia (70%), and thrombocytopenia (70%). All-grade cytokine release syndrome (CRS) was observed in 50% of patients, though no grade ≥3 CRS events were reported. Grade 1 neurological events occurred in 1 patient but were resolved without any intervention. Prolonged cytopenia (grade ≥ 3 at day 29) was reported for 60% of patients. The ORR was 70%, and complete response rate was 50%. The median duration of response was 9.1 months (95% confidence interval [CI], 2.1-not reached), and overall survival was 14.7 months (95% CI, 1.7-not reached). One patient diagnosed with central nervous system involvement after screening but before liso-cel infusion, responded to liso-cel. Liso-cel demonstrated meaningful efficacy and a manageable safety profile in Japanese patients with R/R LBCL.

Matching-adjusted indirect treatment comparison of chimeric antigen receptor T-cell therapies for third-line or later treatment of relapsed or refractory large B-cell lymphoma: lisocabtagene maraleucel versus tisagenlecleucel

Background

There are no head-to-head clinical studies comparing chimeric antigen receptor (CAR) T-cell therapies for the treatment of relapsed or refractory aggressive large B-cell lymphomas. Naive, indirect comparisons may be inappropriate, as the study designs and patient populations could differ substantially. Matching-adjusted indirect comparisons (MAIC) can reduce many biases associated with indirect comparisons between studies. To determine the comparative efficacy and safety of lisocabtagene maraleucel (liso-cel) to tisagenlecleucel, we describe an unanchored MAIC of the pivotal studies TRANSCEND NHL 001 (TRANSCEND; NCT02631044; liso-cel) and JULIET (NCT02445248; tisagenlecleucel).

Methods

Individual patient data (IPD) from TRANSCEND were available to the authors; for the JULIET pivotal study, summary-level data from the published study were used. To balance the populations between two studies, IPD from TRANSCEND were adjusted to match the marginal distribution (e.g., mean, variance) of clinical factors among patients from JULIET.

Results

Results from the primary MAIC showed liso-cel had statistically significant greater efficacy than tisagenlecleucel (objective response rate: odds ratio [OR] = 2.78, 95% confidence interval [CI]: 1.63‒4.74; complete response rate: OR = 2.01, 95% CI: 1.22‒3.30; progression-free survival: hazard ratio [HR] = 0.65, 95% CI: 0.47‒0.91; overall survival: HR = 0.67, 95% CI: 0.47‒0.95). MAIC of safety outcomes showed lower ORs for all-grade and grade ≥ 3 cytokine release syndrome, and grade ≥ 3 prolonged cytopenia for liso-cel when compared with tisagenlecleucel; there were no statistically significant differences detected for other safety outcomes.

Conclusions

Overall, this MAIC of two CAR T-cell therapies indicates liso-cel had favorable efficacy and a comparable or better safety profile relative to tisagenlecleucel.

Clinical trial registration: ClinicalTrials.gov identifiers: NCT02631044 and NCT02445248.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40164-022-00268-z.

Indirect Treatment Comparison of Liso-Cel vs. Salvage Chemotherapy in Diffuse Large B-Cell Lymphoma: TRANSCEND vs. SCHOLAR-1

Most patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) have exhausted their treatment options and are deemed palliative. CD19-directed chimeric antigen receptor (CAR) T-cell therapy has recently been introduced as a new option for these patients. Lisocabtagene maraleucel (liso-cel) is an investigational CAR T-cell therapy that has shown promising activity in this setting. We used an unanchored matching-adjusted indirect comparison (MAIC) methodology to compare liso-cel, using individual patient-level data from the TRANSCEND NHL 001 (TRANSCEND; NCT02631044) trial, to salvage chemotherapy, using summary-level data from the SCHOLAR-1 study, for the treatment of patients with R/R LBCL. Standardized mean differences were used to evaluate imbalances between the TRANSCEND and SCHOLAR-1 studies. MAIC was conducted to determine the relative efficacy of liso-cel vs. salvage chemotherapy with regard to overall survival, complete response rate, and objective response rate. For all efficacy outcomes assessed, comparisons of clinical factors before MAIC showed that five of seven baseline characteristics were similar between the TRANSCEND and SCHOLAR-1 studies; however, age and R/R to last therapy status differed between studies, thus requiring matching and adjusting to ensure the validity of this analysis. The base case analyses demonstrated a significantly lower risk of mortality (hazard ratio, 0.5; 95% confidence interval [CI] 0.4-0.6; p < 0.001) with significantly higher rates of complete response (odds ratio, 12.9; 95% CI 8.0-20.7) and objective response (odds ratio, 7.0; 95% CI 4.6-10.5) for patients treated with liso-cel than patients treated with salvage chemotherapy. MAIC comparisons demonstrated favorable efficacy for liso-cel compared with salvage chemotherapy in the treatment of patients with R/R LBCL.Trial Registration ClinicalTrials.gov identifier: NCT02631044.

Everolimus

Everolimus (RAD001, Afinitor®) is an oral protein kinase inhibitor of the mammalian target of rapamycin (mTOR) serine/threonine kinase signal transduction pathway. The mTOR pathway regulates cell growth, proliferation, and survival and is frequently deregulated in cancer. Everolimus has been approved by the FDA and the EMA for the treatment of advanced renal cell carcinoma (RCC), subependymal giant cell astrocytoma (SEGA) associated with tuberous sclerosis (TSC), pancreatic neuroendocrine tumors (PNET), in combination with exemestane in advanced hormone-receptor (HR)-positive, HER2-negative breast cancer. Everolimus shows promising clinical activity in additional indications. Multiple phase 2 and phase 3 trials of everolimus alone or in combination are ongoing and will help to further elucidate the role of mTOR in oncology. For a review on everolimus as immunosuppressant, please consult other sources.

Sorafenib: targeting multiple tyrosine kinases in cancer

Sorafenib (BAY 43-9006, Nexavar®) is an oral multiple tyrosine kinase inhibitor. Main targets are receptor tyrosine kinase pathways frequently deregulated in cancer such as the Raf-Ras pathway, vascular endothelial growth factor (VEGF) pathway, and FMS-like tyrosine kinase 3 (FLT3). Sorafenib was approved by the FDA in fast track for advanced renal cell cancer and hepatocellular cancer and shows good clinical activity in thyroid cancer. Multiple clinical trials are undertaken to further investigate the role of sorafenib alone or in combination for the treatment of various tumor entities.

Inhibitor of differentiation proteins do not influence prognosis of biliary tract cancer

AIM: To investigate the expression and clinical relevance of inhibitor of differentiation (ID) proteins in biliary tract cancer.

METHODS: ID protein expression was analyzed in 129 samples from patients with advanced biliary tract cancer (BTC) (45 extrahepatic, 50 intrahepatic, and 34 gallbladder cancers), compared to normal controls and correlated with clinical an pathological parameters.

RESULTS: ID1-3 proteins are frequently overexpressed in all BTC subtypes analyzed. No correlation between increased ID protein expression and tumor grading, tumor subtype or treatment response was detected. Survival was influenced primary tumor localization (extrahepatic vs intrahepatic and gall bladder cancer, OS 1.5 years vs 0.9 years vs 0.7 years, P = 0.002), by stage at diagnosis (OS 2.7 years in stage I vs 0.6 years in stage IV, P < 0.001), resection status and response to systemic chemotherapy. In a multivariate model, ID protein expression did not correlate with clinical prognosis. Nevertheless, there was a trend of shorter OS in patients with loss of cytoplasmic ID4 protein expression (P = 0.076).

CONCLUSION: ID protein expression is frequently deregulated in BTC but does not influence clinical prognosis. Their usefulness as prognostic biomarkers in BTC is very limited.

ID2 and ID3 protein expression mirrors granulopoietic maturation and discriminates between acute leukemia subtypes

The inhibitors of DNA binding (ID) inhibit basic helix-loop-helix transcription factors and thereby guide cellular differentiation and proliferation. To elucidate the involvement of IDs in hematopoiesis and acute leukemias (AL), we analyzed ID2 and ID3 expression in hematopoiesis and leukemic blasts in bone marrow biopsies (BMB). BMB of healthy stem cell donors (n = 19) and BMB of patients with acute myeloid leukemia (AML) with myelodysplasia-related changes (AML-MD; n = 19), de novo AML (n = 20), B-acute lymphoblastic leukemia (B-ALL) (n = 23), T-ALL (n = 19), were immunohistochemically stained for ID2 and ID3 expression. The expression patterns were evaluated and quantified for each hematopoietic lineage and each leukemia subtype. In normal BMB, immature granulopoiesis showed weak ID2 and strong ID3 expression, which was lost during maturation (p < 0.001). Erythropoiesis remained negative for ID2/3 (p < 0.001). ID2/3 expression differed between immature granulopoiesis and leukemic blasts (p < 0.001). Moreover, differential ID2/3 expression was seen between AL subgroups: AML, especially AML-MD, had more ID2- (p < 0.001) and ID3-positive (p < 0.001) blasts than ALL. We show a comprehensive in situ picture of ID2/3 expression in hematopoiesis and AL. Morphologically, ID2/3 proteins seem to be involved in the granulopoietic maturation. Importantly, the distinct ID2/3 expression patterns in AL indicate a specific deregulation of ID2/3 in the various types of AL and may support subtyping of AL.

Safety, tolerability, and pharmacokinetics of a single dose of pasireotide long-acting release in healthy volunteers: a single-center Phase I study

OBJECTIVE

This study was conducted to evaluate the safety, tolerability, and pharmacokinetics (PKs) of different doses of a long-acting release (LAR) formulation of pasireotide in healthy subjects.

DESIGN

Single-center, open-label, randomized Phase I study.

METHODS

Twelve healthy male subjects received a single s.c. dose of pasireotide 300 μg followed by a washout period of 7 days (or at least 5 days), before receiving an i.m. injection of pasireotide -LAR 40 mg (n=5) or 60 mg (n=7). Assessments included adverse events (AEs), PKs, and glucose, insulin, glucagon, and HbA1c levels.

RESULTS

Pasireotide LAR showed an extended-release profile over 1 month with two concentration peaks observed 1 and around 20 days after injection. The area under curve exposure of pasireotide LAR was dose proportional when the dose levels were compared, and the bioavailability of the LAR relative to the s.c. formulation was complete. Administration of pasireotide LAR resulted in an increase in fasting and postprandial glucose levels; however, an attenuation of the hyperglycemic effect was observed after 15 days. The most frequently reported AEs were mild-to-moderate diarrhea, abdominal pain, and flatulence. Only gastrointestinal AEs and injection site reactions were suspected to be drug related.

CONCLUSIONS

Pasireotide LAR was generally well tolerated with mostly mild AEs at doses up to 60 mg and showed a dose-proportional, extended-release profile in healthy subjects. Based on the favorable results of this study, further clinical development of pasireotide LAR is under way, which will give insight into the PKs, efficacy, and safety of pasireotide LAR in patient populations.

Somatostatin receptors in non-neuroendocrine malignancies: the potential role of somatostatin analogs in solid tumors

Somatostatin receptors (sstrs) are G-protein-coupled receptors that mediate various physiological effects when activated by the neuropeptide somatostatin or its synthetic analogs. In addition to the well-documented antisecretory effects of sstr2-preferential somatostatin analogs octreotide and lanreotide, ligand binding to sstr initiates an inhibitory action on tumor growth. This effect may result from both indirect actions (suppression of growth factors and growth-promoting hormones [e.g., GH/IGF-1 axis] and inhibition of angiogenesis) and direct actions (activation of antigrowth activities [e.g., apoptosis]). As solid tumor cells express multiple sstrs, there is a rationale to evaluate the potential antitumor effects of pasireotide (SOM230), a multireceptor-targeted somatostatin analog with high binding affinity for sstr1–3 and sstr5. Pasireotide reduces systemic IGF-1 levels more potently than currently available somatostatin analogs and has been well tolerated in clinical trials.

The potential role of somatostatin analogues in the treatment of gastrointestinal (GI) cancers

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Background: Somatostatin receptors (sstr) are expressed in various normal and malignant tissues, including non-neuroendocrine GI solid tumors. Gastric cancer (GC) cells mainly express sstr2 and sstr5, colorectal cancer (CRC) cells predominantly express sstr1 followed by sstr5 and sstr2, and hepatocellular carcinoma (HCC) cells express mainly sstr5 as well as sstr1,2,3. Somatostatin analogues (SAs) may have direct and indirect antitumor activity. Octreotide and lanreotide primarily target sstr2, whereas the new agent pasireotide has high affinity for sstr1,2,3 and sstr5.

Methods: Published data evaluating the antitumor properties of SAs in GI tumors were reviewed.

Results: The table lists the results of clinical studies in which SAs were evaluated as antitumor therapies in GI cancers.

Conclusions: Although octreotide and lanreotide are efficacious in the treatment of symptoms of neuroendocrine tumors, these agents have demonstrated mixed results in the antitumor treatment of non-neuroendocrine GI tumors. Data suggesting potential favorable outcomes with SAs alone or in combination with other agents have been seen in solid tumors with predominant sstr2 expression such as GC. Novel SAs such as pasireotide may have improved antitumor effects in non-neuroendocrine solid tumors expressing multiple sstr compared with octreotide and lanreotide.

[Table: see text]

[Table: see text]

Inhibition of Id proteins by a peptide aptamer induces cell-cycle arrest and apoptosis in ovarian cancer cells

Background:

Inhibitors of DNA-binding proteins (Id1-4), lacking the basic DNA-binding domain, function as dominant inhibitors of cell-cycle regulators. Overexpression of Id proteins promotes cancer cell proliferation and resistance against apoptosis. Level of Id protein expression, especially of Id1, correlates with poor differentiation, enhanced malignant potential and more aggressive clinical behaviour of ovarian tumours. Although overexpression of Ids has been found and shown to correlate with poor clinical outcome, their inhibition at protein level has never been studied.

Methods:

A peptide aptamer, Id1/3-PA7, targeting Id1 and Id3, was isolated from a randomised combinatorial expression library using yeast and mammalian two-hybrid systems. Id1/3-PA7 was fused, expressed and purified with a cell-penetrating protein transduction domain.

Results:

Intracellular-delivered Id1/3-PA7 colocalised to Id1 and Id3. It induced cell-cycle arrest and apoptosis in ovarian cancer cells ES-2 and PA-1. It activated the E-box promoter and increased the expression level of cyclin-dependent kinase inhibitor (CDKN2A) in a dose-dependent manner that is paralleled by the cleavage of poly-ADP ribose polymerase. These effects were counteracted by ectopically overexpressed Id1 and Id3.

Conclusion:

Id1/3-PA7 could represent an exogenous anti-tumour agent that can significantly trigger cell-cycle arrest and apoptosis in ovarian cancer.

Targeting Id1 and Id3 by a specific peptide aptamer induces E-box promoter activity, cell cycle arrest, and apoptosis in breast cancer cells

Inhibitors of differentiation or DNA binding (Id) proteins have been shown to be involved in tumor growth, invasiveness, metastasis, and angiogenesis. Overexpression of Id proteins, especially Id1, correlates with unfavorable clinical prognosis. Thus, they are attractive molecular targets for anticancer therapy. Overexpression of Id proteins mediates breast cancer metastasis to lung. Targeting Id1 and Id3 expression in breast cancer cells reduces breast cancer metastasis in animal models. Different breast tumors failed to grow and/or metastasize in Id1 (+/-) Id3 (-/-) mice. Id1 and Id3 preferentially dimerize with the key regulatory E-proteins which inhibit the expression of different tumor suppressor genes. Nevertheless, the inhibition of tumorigenic activities of Id1 and Id3 at protein level has never been studied. Here, we isolated a novel peptide aptamer, Id1/3-PA7, specifically interacting with Id1 and Id3 from randomized combinatorial expression library using yeast and mammalian two-hybrid systems. Intracellular delivered Id1/3-PA7 co-localized to Id1 and Id3 and interfered with their functions. It repressed E47 protein sequestration by Id1 and Id3, activated the E-box promoter and increased the expression level of cyclin-dependent kinase inhibitors (CDKN1A and CDKN1B) in a dose-dependent fashion, paralleled by the cleavage of poly ADP ribose polymerase (PARP). These effects were counteracted by ectopically overexpressed Id1 and Id3. Peptide aptamer Id1/3-PA7 induced cell cycle arrest and apoptosis in breast cancer cells MCF7 and MDA-MB-231. In conclusion, Id1/3-PA7 could represent a nontoxic exogenous agent that can significantly provoke antiproliferative and apoptotic effects in breast cancer cells, which are associated with deregulated expression of Id1 and Id3.

Elevated endogenous expression of the dominant negative basic helix-loop-helix protein ID1 correlates with significant centrosome abnormalities in human tumor cells

Background

ID proteins are dominant negative inhibitors of basic helix-loop-helix transcription factors that have multiple functions during development and cellular differentiation. Ectopic (over-)expression of ID1 extends the lifespan of primary human epithelial cells. High expression levels of ID1 have been detected in multiple human malignancies, and in some have been correlated with unfavorable clinical prognosis. ID1 protein is localized at the centrosomes and forced (over-)expression of ID1 results in errors during centrosome duplication.

Results

Here we analyzed the steady state expression levels of the four ID-proteins in 18 tumor cell lines and assessed the number of centrosome abnormalities. While expression of ID1, ID2, and ID3 was detected, we failed to detect protein expression of ID4. Expression of ID1 correlated with increased supernumerary centrosomes in most cell lines analyzed.

Conclusions

This is the first report that shows that not only ectopic expression in tissue culture but endogenous levels of ID1 modulate centrosome numbers. Thus, our findings support the hypothesis that ID1 interferes with centrosome homeostasis, most likely contributing to genomic instability and associated tumor aggressiveness.

BI_2536--targeting the mitotic kinase Polo-like kinase 1 (Plk1)

Human Polo-like kinase 1 (Plk1) is an essential regulator of mitotic progression. Targeted inhibition of this kinase was effective in killing tumor cells in vitro and in vivo. The Plk1 inhibitor BI_2536 was well tolerated and showed antitumor activity in the first clinical trials enrolling patients with advanced solid tumors and refractory or relapsed acute myeloid leukemia.

Sorafenib

Sorafenib (BAY 43-9006, Nexavar) is a novel oral kinase inhibitor that targets multiple tyrosine kinases in vivo and in vitro. Main targets are receptor tyrosine kinase pathways frequently deregulated in cancer such as the raf-ras pathway, vascular endothelial growth factor (VEGF) pathway, and FMS-like tyrosine kinase 3 (FLT3). Sorafenib was approved by the FDA in fast track for advanced renal cell cancer and hepatocellular cancer and shows good clinical activity in thyroid cancer. Multiple clinical trials are undertaken to further investigate the role of sorafenib alone or in combination for the treatment of various tumor entities.

Severe Organizing Pneumonia after Two Cycles of Docetaxel as Fourth-Line Chemotherapy for Advanced Non-Small Cell Carcinoma of the Lung

Organizing pneumonia (formerly known as bronchiolitis obliterans organizing pneumonia, BOOP) is an inflammatory process of the bronchioles that can lead to the destruction of small airways and surrounding lung tissue. Although the majority of cases are idiopathic, certain chemicals and drugs can induce OP. Here, we report a 54-year-old male patient with advanced non-small cell lung cancer (NSCLC) who developed therapy-associated OP. He had undergone several other chemotherapies before being switched to docetaxel as monotherapy (75 mg/m(2)). Treatment was initially well tolerated, but after the second cycle the patient developed increasing shortness of breath. Computed tomography (CT) for staging after the second cycle showed bilateral predominantly interstitial infiltration highly suggestive of acute lung fibrosis. Bronchoscopy revealed signs of chronic bronchitis and watery discharge from both lungs. Bronchoalveolar lavage and transbronchial needle biopsy was performed. Based on histopathologic examination, diagnosis of OP was made. After cessation of docetaxel and initial high dose steroids, the infiltration ameliorated rapidly. This is the second case in the literature that associates docetaxel with rapid onset of bronchiolitis obliterans. Therefore, patients with lung cancer receiving docetaxel who develop respiratory symptoms should be suspected to develop OP.

Complete caval thrombosis secondary to an implanted venous port--a case study

HISTORY AND CLINICAL FINDINGS

We report the case of a woman who presented to the medical emergency room with upper thoracic inlet syndrome six months after being treated for cancer of the left breast with surgery, radiation, and chemotherapy. A port-related occlusion of the superior vena cava was diagnosed on the basis of the history, physical findings, and diagnostic images.

METHODS

The local standards for the handling of port systems are presented.

DISCUSSION

Implanted port systems facilitate the treatment of the chronically ill by enabling easy and safe venous access. As the number of patients with such systems is growing, there is an increased need for optimized handling and care, awareness of the risks (such as catheter occlusion, thrombosis, and infection), and recognition of complications when they arise.

Interference of the dominant negative helix-loop-helix protein ID1 with the proteasomal subunit S5A causes centrosomal abnormalities

The inhibitor of DNA-binding (ID) proteins are dominant-negative inhibitors of basic helix-loop-helix transcription factors that have multiple functions during development and cellular differentiation. High-level expression of some ID family members has been observed in human malignancies, and in some cases was correlated with poor clinical prognosis. Ectopic ID1 expression extends the life span of primary human epithelial cells, inhibits cellular differentiation and induces centrosome duplication errors, thus suggesting that ID1 may have oncogenic activities. ID1 can bind to the proteasomal subunit S5A/Rpn10, but the biological consequences of the interaction have not been studied in detail. Here, we show that ID1's ability to induce supernumerary centrosomes correlates with S5A binding. Similar to ID1, a fraction of the S5A protein localizes to centrosomal structures. Furthermore, partial depletion of S5A by RNA interference causes accumulation of cells with supernumerary centrosomes. These results are consistent with the model that ID1 dysregulates centrosome homeostasis at least in part by interfering with S5A activities at the centrosome.

[Origin and role of aneuploidy in cancer]

Genetic aberrations of cancer cells have a profound impact for prognosis in several malignant neoplasias. The understanding of their origin is the basis for the development of new therapeutic options. Aneuploidy is observed in a large variety of premalignancies and tumors. Aneuploid cells harbor less or more than 46 chromosomes. The exact role of aneuploidy in tumorigenesis is still not clear. It has long been debated, whether aneuploidy directly contributes to tumorigenesis or reflects nonspecific changes during tumor progression. Several mechanisms are thought to be responsible for the generation of aneuploid sets of chromosomes: these comprise failure in cell division, such as defective chromosome separation caused by compromised mitotic checkpoint signaling or centrosome aberrations. Moreover, telomere shortening and defective DNA-damage signaling appear to be powerful driving forces of genomic instability. The loss of telomere sequences at the end of each chromosome and DNA double-strand breakage accompanied by compromised damage signaling favor fusion of chromosomes and generation of aneuploidy. Furthermore, aneuploidy arises to a much higher degree from a tetraploid state when compared to diploid cells. The frequent observation of the described defects in pre- and malignant cells supports the hypothesis that aneuploidy contributes to tumorigenesis.

The helix-loop-helix protein ID1 localizes to centrosomes and rapidly induces abnormal centrosome numbers

ID1 is a member of the inhibitor of DNA binding/differentiation (ID) family of dominant negative helix-loop-helix transcription factors. ID-proteins have been implicated in the control of differentiation and transcriptional modulation of various cell cycle regulators and high levels of ID1 expression are frequently detected in various cancer types. However, it is unclear whether ID1 is a marker of highly proliferative cancer cells or whether it directly contributes to the tumor phenotype. A detailed analysis of ID1-expressing human cells revealed that a fraction of ID1 localizes to centrosomes. Ectopic expression of ID1 in primary cells and tumor cell lines resulted in accumulation of cells with abnormal centrosome numbers. There was no evidence for centrosomal localization or induction of centrosome abnormalities by the other ID family members. Hence, ID1 may contribute to oncogenesis not only by inhibiting transcriptional activity of basic helix-loop-helix transcription factors and abrogate differentiation but also by subverting centrosome duplication.

Boswellia: an evidence-based systematic review by the Natural Standard Research Collaboration

An evidence-based systematic review including written and statistical analysis of scientific literature, expert opinion, folkloric precedent, history, pharmacology, kinetics/dynamics, interactions, adverse effects, toxicology, and dosing.

Abrogation of the retinoblastoma tumor suppressor checkpoint during keratinocyte immortalization is not sufficient for induction of centrosome-mediated genomic instability

Deregulation of the retinoblastoma (pRB) tumor suppressor pathway and telomerase activation have been identified as rate-limiting steps for immortalization of primary human epithelial cells. However, additional molecular aberrations including p53 inactivation, ras activation, and deregulation of protein phosphatase 2A activity are necessary for full transformation of immortalized epithelial cells. Genomic instability is observed in most human tumors and constitutes an important mechanism to allow emerging tumor cells to acquire additional mutations to efficiently overcome selection barriers during carcinogenic progression. In an attempt to model oral cancer in a human cell-based system, we analyzed normal oral epithelial keratinocytes with the pRB pathway dysregulated by loss of expression of the cyclin-dependent kinase (cdk) 4/cdk6 inhibitor p16(INK4A) and/or ectopic expression of cdk4 or expression of the human papillomavirus (HPV) type 16 E7 oncoprotein. Ectopic expression of cdk4 and HPV-16 E7 was equally efficient in extending the life span of normal oral keratinocytes, and each was able to cooperate with telomerase (hTERT) to immortalize these cells. HPV-16 E7/hTERT-immortalized normal oral keratinocytes showed centrosome abnormalities, whereas populations of cdk4/hTERT-immortalized cells or hTERT-immortalized cells that had lost expression of p16INK4A showed no such abnormalities. These results demonstrate that disruption of the p16INK4A/pRB checkpoint of epithelial cell immortalization does not necessarily lead to centrosome-associated genomic instability.

Id proteins--tumor markers or oncogenes?

The Id (Inhibitor of differentiation or Inhibitor of DNA-binding) proteins act as dominant negative inhibitors of differentiation-specific basic Helix-Loop-Helix (bHLH) transcription factors. Id proteins negatively regulate cellular differentiation and they induce proliferation by modulating different cell cycle regulators both by direct and indirect mechanisms. Ectopic expression of Id proteins in tissue culture models can result in cellular immortalization and abrogation of differentiation processes. Recent reports show that Id proteins are overexpressed in various cancer types implying a role of these regulatory proteins in carcinogenesis. This review focuses on the biology of the Id proteins and their role as potential oncogenes.

Differential cell cycle response of nontumorigenic and tumorigenic human papillomavirus-positive keratinocytes towards transforming growth factor-beta1

Human papillomaviruses (HPVs) are causative agents of a number of malignancies in humans, including cervical cancer. Their tumorigenic potential is linked to expression of the viral E6/E7 genes which can interfere with normal cell cycle control by targeting p53, p21WAF1, p27KIP1, and pRb. We show here that nontumorigenic and tumorigenic HPV-positive keratinocytes (HPK) exhibit striking differences in the response of cell cycle regulatory genes towards transforming growth factor beta-beta1. Treatment with this agent led to an efficient induction of p53 and the growth-inhibitory p15INK4 and p21WAF1 genes only in nontumorigenic HPKs and was linked to an efficient reduction in viral E6/E7 oncogene expression. This was associated with increased pRb levels, exhibiting sustained hypophosphorylation, and a permanent growth arrest in the G1 phase of the cell cycle. In contrast, tumorigenic HPKs exhibited only a modest rise in p53 protein levels and a substantially reduced induction of the p15INK4 and p21WAF1 genes, which was linked to a lesser degree of viral oncogene repression. In addition, tumorigenic HPKs rapidly resumed cell growth after a transient G1 arrest, concomitantly with the reappearance of hyperphosphorylated pRb. These results support the notion that the progression of HPV-positive cells to a malignant phenotype is associated with increased resistance to growth inhibition by transforming growth factor-beta1. This is linked in the tumorigenic cells to a lack of persistent G1 arrest, inefficient induction of several cell cycle control genes involved in growth inhibition, and inefficient repression of the growth-promoting viral E6/E7 oncogenes.

Immortalization of primary human keratinocytes by the helix-loop-helix protein, Id-1

Basic helix-loop-helix (bHLH) DNA-binding proteins have been demonstrated to regulate tissue-specific transcription within multiple cell lineages. The Id family of helix-loop-helix proteins does not possess a basic DNA-binding domain and functions as a negative regulator of bHLH proteins. Overexpression of Id proteins within a variety of cell types has been shown to inhibit their ability to differentiate under appropriate conditions. We demonstrate that ectopic expression of Id-1 leads to activation of telomerase activity and immortalization of primary human keratinocytes. These immortalized cells have a decreased capacity to differentiate as well as activate phosphorylation of the retinoblastoma protein. Additionally, these cells acquire an impaired p53-mediated DNA-damage response as a late event in immortalization. We conclude that bHLH proteins play a pivotal role in regulating normal keratinocyte growth and differentiation, which can be disrupted by the immortalizing functions of Id-1 through activation of telomerase activity and inactivation of the retinoblastoma protein.

Alterations in cyclin-dependent kinase 2 function during differentiation of primary human keratinocytes

Terminal differentiation of epithelial cells is intimately linked to cell-cycle withdrawal. The tight coupling of these two processes is critical to maintenance of epidermal tissue homeostasis and is frequently disrupted in squamous cell carcinoma. To identify possible molecular targets of epithelial carcinogenesis, we investigated the regulatory pathways that couple cellular differentiation and proliferation in primary cultures of human keratinocytes and found that the cyclin-dependent kinase inhibitors (CKIs) p21cip1/waf1 and p27kip1 were induced early during differentiation of human keratinocytes, whereas p15ink4B was induced later in differentiation. The induction of p21c1/waf1 was mediated by both transcriptional and non-transcriptional mechanisms, and the activities of cyclin A/cyclin-dependent kinase (cdk) 2 and cyclin E/cdk2 complexes were specifically inhibited during keratinocyte differentiation. In contrast, p21cip1/wafl did not associate with cdk4, and the activities of cdk4 complexes remained unchanged. Hence, our results support the model that multiple CKIs participate in linking cellular proliferation and differentiation in human keratinocytes by specific modulation of cdk2 activity.