The type 1 insulin-like growth factor receptor pathway

Research conducted over the past two decades has shown the importance of the type 1 insulin-like growth factor receptor (IGF1R) in tumorigenesis, metastasis, and resistance to existing forms of cancer therapy. The IGF1R itself has only recently been accepted as a credible treatment target, however, perhaps reflecting the potential problems for drug design posed by normal tissue IGF1R expression, and close homology with the insulin receptor. Currently approximately 12 anti-IGF1R therapeutics are undergoing clinical evaluation, including blocking antibodies and tyrosine kinase inhibitors. This review will summarize the principal signaling pathways activated by IGF1R and the preclinical data that validated this receptor as a treatment target. We will review clinical progress in the testing of IGF1R inhibitory drug candidates, the relative benefits and potential toxicities of coinhibition of the insulin receptor, and the rationale for combining IGF1R blockade with other cancer treatments. An understanding of IGF1R signaling is important because it will guide the incorporation of appropriate molecular markers into clinical trial design. This will be key to the identification of patients most likely to benefit, and so will influence the ability of IGF1R inhibition to make the transition from experimental intervention to clinical therapy.

Type 1 insulin-like growth factor receptor translocates to the nucleus of human tumor cells

The type 1 insulin-like growth factor receptor (IGF-1R) is a transmembrane glycoprotein composed of two extracellular alpha subunits and two beta subunits with tyrosine kinase activity. The IGF-1R is frequently upregulated in cancers and signals from the cell surface to promote proliferation and cell survival. Recent attention has focused on the IGF-1R as a target for cancer treatment. Here, we report that the nuclei of human tumor cells contain IGF-1R, detectable using multiple antibodies to alpha- and beta-subunit domains. Cell-surface IGF-1R translocates to the nucleus following clathrin-mediated endocytosis, regulated by IGF levels. The IGF-1R is unusual among transmembrane receptors that undergo nuclear import, in that both alpha and beta subunits traffic to the nucleus. Nuclear IGF-1R is phosphorylated in response to ligand and undergoes IGF-induced interaction with chromatin, suggesting direct engagement in transcriptional regulation. The IGF dependence of these phenomena indicates a requirement for the receptor kinase, and indeed, IGF-1R nuclear import and chromatin binding can be blocked by a novel IGF-1R kinase inhibitor. Nuclear IGF-1R is detectable in primary renal cancer cells, formalin-fixed tumors, preinvasive lesions in the breast, and nonmalignant tissues characterized by a high proliferation rate. In clear cell renal cancer, nuclear IGF-1R is associated with adverse prognosis. Our findings suggest that IGF-1R nuclear import has biological significance, may contribute directly to IGF-1R function, and may influence the efficacy of IGF-1R inhibitory drugs.

Interferon-Gamma-Producing CD8+ Tissue Resident Memory T Cells Are a Targetable Hallmark of Immune Checkpoint Inhibitor-Colitis

BACKGROUND & AIMS

The pathogenesis of immune checkpoint inhibitor (ICI)-colitis remains incompletely understood. We sought to identify key cellular drivers of ICI-colitis and their similarities to idiopathic ulcerative colitis, and to determine potential novel therapeutic targets.

METHODS

We used a cross-sectional approach to study patients with ICI-colitis, those receiving ICI without the development of colitis, idiopathic ulcerative colitis, and healthy controls. A subset of patients with ICI-colitis were studied longitudinally. We applied a range of methods, including multiparameter and spectral flow cytometry, spectral immunofluorescence microscopy, targeted gene panels, and bulk and single-cell RNA sequencing.

RESULTS

We demonstrate CD8⁺ tissue resident memory T (T_RM) cells are the dominant activated T cell subset in ICI-colitis. The pattern of gastrointestinal immunopathology is distinct from ulcerative colitis at both the immune and epithelial-signaling levels. CD8⁺ T_RM cell activation correlates with clinical and endoscopic ICI-colitis severity. Single-cell RNA sequencing analysis confirms activated CD8⁺ T_RM cells express high levels of transcripts for checkpoint inhibitors and interferon-gamma in ICI-colitis. We demonstrate similar findings in both anti-CTLA-4/PD-1 combination therapy and in anti-PD-1 inhibitor-associated colitis. On the basis of our data, we successfully targeted this pathway in a patient with refractory ICI-colitis, using the JAK inhibitor tofacitinib.

CONCLUSIONS

Interferon gamma-producing CD8⁺ T_RM cells are a pathological hallmark of ICI-colitis and a novel target for therapy.

Use of complementary therapies by patients with IBD may indicate psychosocial distress

BACKGROUND

Complementary and alternative medicine (CAM) is used increasingly by patients with chronic diseases. We have assessed the use of CAM in general medicine and gastrointestinal outpatients focusing particularly on factors predisposing to its use in patients with inflammatory bowel disease (IBD).

METHODS

239 consecutive patients attending gastrointestinal and general medical outpatient clinics answered a questionnaire about their use of CAM: patients with IBD also completed a validated disease-specific quality of life (QOL) inflammatory bowel disease questionnaire (IBDQ).

RESULTS

26% of all patients used CAM, most commonly herbal remedies (43%). CAM was used significantly more by younger than older patients and by single than married or widowed ones. There were no differences by gender or ethnicity. More patients with irritable bowel syndrome used CAM than those with other diagnoses. In IBD patients, CAM users had significantly poorer QOL scores for emotional and social factors than nonusers. 53% of users stated that CAM alleviated their symptoms.

CONCLUSIONS

Use of CAM is common in gastroenterological outpatients, particularly if they are young, single, or have irritable bowel syndrome (IBS). Most patients deem it helpful. In IBD, poor QOL predisposes to use of CAM. Conversely, use of CAM may serve as a marker of emotional or social unease in these patients. Physicians need to be aware of widespread usage of CAM by their patients.

Immune checkpoint inhibitor-related colitis assessment and prognosis: can IBD scoring point the way?

BACKGROUND

Immune checkpoint inhibitors (ICI) improve survival but cause immune-related adverse events (irAE). We sought to determine if CTCAE classification, IBD biomarkers/endoscopic/histological scores correlate with irAE colitis outcomes.

METHODS

A dual-centre retrospective study was performed on patients receiving ICI for melanoma, NSCLC or urothelial cancer from 2012 to 2018. Demographics, clinical data, endoscopies (reanalysed using Mayo/Ulcerative Colitis Endoscopic Index of Severity (UCEIS) scores), histology (scored with Nancy Index) and treatment outcomes were analysed.

RESULTS

In all, 1074 patients were analysed. Twelve percent (134) developed irAE colitis. Median patient age was 66, 59% were male. CTCAE diarrhoea grade does not correlate with steroid/ infliximab use. G3/4 colitis patients are more likely to need infliximab (p < 0.0001) but colitis grade does not correlate with steroid duration. CRP, albumin and haemoglobin do not correlate with severity. The UCEIS (p = 0.008) and Mayo (p = 0.016) scores correlate with severity/infliximab requirement. Patients with higher Nancy indices (3/4) are more likely to require infliximab (p = 0.03).

CONCLUSIONS

CTCAE assessment does not accurately reflect colitis severity and our data do not support its use in isolation, as this may negatively impact timely management. Our data support utilising endoscopic scoring for patients with >grade 1 CTCAE disease, and demonstrate the potential prognostic utility of objective histologic scoring.

The spectrum of anorectal malformations in Africa

Anorectal malformations (ARM) remain a significant birth defect with geographic variation in incidence, individual phenotypes and regional geographic subtypes. Although early studies indicated a low incidence in Black patients, there is a great paucity of knowledge as to the types, frequency and incidence of ARMs encountered in the African continent and their associated anomalies. Current evidence suggests a significant clinical load. This study set out to evaluate ARM in Southern and other parts of Africa to define the clinical load of ARM. We retrospectively collected data on 1,401 ARM patients from six South African Paediatric Surgical units plus representative samples from five other African countries from West, Central and Southern Africa. Data included ethnic group, age, gender as well as the anatomical pathology, classification and presence or absence of associated anomalies. ARM lesions classified by the Wingspread classification plus an analysis of fistula position was carried out in evaluable cases for purposes of comparison. South African centres reported a higher prevalence of cloacae and vestibular fistulae, whereas rectovaginal, recto prostatic and anorectal malformation without fistula were more prevalent in the Northern African group. 76% of 1,401 patients were ethnically Black African [gender ratio = 2 (vs gender ratio 1.38 overall)] and 49.8% were "low" lesions (Wingspread classification). High or intermediate lesions were mostly males (72%). Anal stenosis was most prevalent in black males and non-Black females. Fistulae were identified in 95% with 682 (52%) being low (perineal/covered anus/vestibular) fistulae. Perineal fistulae had a male predilection (n = 260; 20%), whereas vestibular fistulas (n = 416; 32%) was strikingly frequent in black females (55%). Of the remainder, 15 fistulae were rectovesical (1.2%), 544 recto-urethral or prostatic (42%), 16 recto-vaginal (1.2%). In addition, there were 43 cloacal lesions (3.3%). Isolated rare ARM anomalies included "Pouch" colon (2) and H-type fistula (2). Isolated lesions occurred in 81% but 163 associated anomalies were identified in 114 patients. These included chromosomal lesions (10), genito-urinary anomalies (50), genital (16), cardiac (31), skeletal anomalies (33), gastro-intestinal malformations (28). Other anomalies included CNS anomalies (14), anterior abdominal wall defects (2) and facial (8) abnormalities and neuroblastoma (1). The ARM is not uncommon in Black African populations and constitutes a significant clinical load to surgical practice in Africa. Ethnic differences appear to exist and vestibular fistulae predominate in black females. Cloaca (3.3%) did appear to be more prevalent. Isolated lesions are frequent but the types of associated anomalies appear similar to other series except chromosomal syndromes. This study illustrates the need for more objective data from developing countries to assess geographical differences.

The release of leptin and its effect on hormone release from human pituitary adenomas

BACKGROUND

Leptin is the protein product of the obese gene, known to play an important role in body energy balance. The leptin receptor exists in numerous isoforms, the long isoform being the major form involved in signal transduction. Leptin expression has recently been demonstrated in the human pituitary, both in normal tissue and in pituitary adenomas. The long isoform of the leptin receptor has also been shown to be present in pituitary adenomas; however, contrasting results have been obtained regarding its expression in the normal human pituitary.

AIM

The aim of this study was (i) to investigate the presence and pattern of distribution of leptin mRNA and the long isoform of its receptor mRNA in the normal pituitary and in different types of pituitary adenomas with RT-PCR; (ii) to study leptin secretion from human pituitary tumours in culture and (iii) to assess in vitro pituitary hormone release following stimulation with human leptin.

RESULTS

Leptin receptor long isoform expression was detected in 2/4 GH-secreting adenomas, 12/17 non-functioning adenomas, 5/9 ACTH-secreting adenomas, 1/2 prolactinomas, 2/2 FSH-secreting adenomas and 5/5 normal pituitaries. The receptor long isoform did not segregate with any particular tumour type, and varying levels of expression were detected between the tissues studied. Leptin mRNA was detected at a low level of expression in 2/7 GH-secreting adenomas, 9/14 non-functioning adenomas, 2/3 ACTH-secreting adenomas, 1/3 prolactinomas and 1/3 FSH-secreting adenomas. We were unable to detect leptin mRNA in any of the five normal pituitaries removed at autopsy; however, immunostaining of a non-tumorous pituitary adjacent to an adenoma removed at transsphenoidal surgery showed scattered leptin positive cells. Culture of pituitary adenomas showed that 16/47 released leptin into the incubation media. Leptin release did not correlate with tumour type or with any of the other pituitary hormones released. In vitro leptin stimulation of pituitary tumours caused stimulation of FSH and alpha-subunit secretion from a non-functioning adenoma and TSH secretion from a somatotroph adenoma.

CONCLUSION

We conclude that not only is leptin stored within the pituitary, but it may also be released from pituitary cells and modulate other pituitary hormone secretion. Pituitary leptin may therefore be a novel paracrine regulator of pituitary function.

Retrospective surveillance of intussusception in South Africa, 1998-2003

BACKGROUND

Intussusception is a common gastrointestinal emergency in children and appears to have a somewhat different clinical spectrum in developing countries. Its etiology is still unclear, but a link to infective agents and viruses has been highlighted. This study aimed to assess the clinical spectrum and prevalence of intussusception in children from the diverse South African population.

METHODS

Retrospective data were obtained from 9 participating pediatric referral units on the occurrence of intussusception in South African children (<14 years old) during a 6-year period (1998-2003). Results were correlated with national population statistics. Intussusception was anatomically classified into ileoileal, ileocolic, and colocolic types. The clinical features, management, outcome, and possible causes were examined.

RESULTS

We reviewed the occurrence and clinical spectrum of intussusception in 423 children (age, 0-14 years) presenting with acute intussusception to 9 pediatric surgical centers. The mean duration of symptoms was 1.5 days, but a delayed presentation was common (median delay, 2.3 days). Intussusception occurred throughout the year, with a peak in the summer months. The majority of patients (89%) were <2 years old, and 78% presented at age 3-18 months of age. Crude population estimates indicate an occurrence of 1 case per 3123 population <2 years old. Only 11% of patients presented after 2 years of age, and the age at presentation was significantly lower (P < .05) in black African patients. All ethnic groups were affected. In 84% of patients, intussusception occurred at the ileocolic region junction, in 7% it was ileoileal, and in 9% it was colocolic. Colocolic intussusception appeared more common in black African patients, and associated pathologic conditions (polyps and Burkitt's lymphoma) occurred mainly in older children. Surgical intervention was required in 81% of patients and involved resection of gangrenous bowel in 40%.

CONCLUSION

Intussusception appears to be a relatively frequent occurrence in children in South Africa. Although the clinical spectrum appears to vary, there is an apparent link to intestinal infection, which requires further investigation. A collaborative approach is required to ascertain the relationship of intussusception to preventable infections and to improve its diagnosis and management.

Mixed-function oxidase enzymes in adriamycin-sensitive and resistant sublines of P-388 leukemia

Levels of mixed-function oxidase (MFO) enzymes were measured in adriamycin(ADR)-sensitive murine leukemia P-388 and its ADR-resistant subline P-388/ADR. The subcellular fractions of the resistant cells showed decreased contents of MFO components, cytochrome P-450 and cytochrome b5, in comparison with the identically prepared fractions of the parental tumor. Similarly, the levels of 7-ethoxycoumarin O-deethylase and the rate of ascorbate induced lipid peroxidation in vitro showed lower values in resistant tumor cells than those of P-388 tumor cells. The observed differences in the two tumor cell types were found to be considerably enhanced if the tumor cells were exposed in vitro to ADR before fractionation. The magnitude of induction of the MFO enzymes was significantly greater in the ADR exposed P-388 cells. The corresponding inducibility was suppressed in the drug exposed resistant tumor cells.

Expression of the multidrug transporter P-glycoprotein and in vitro chemosensitivity: correlation with in vivo response to chemotherapy in acute myeloid leukemia

Thirty four patients with acute myeloid leukemia (AML) (30 de novo and 4 relapsed) were evaluated for P-glycoprotein (P-gp) expression, and in vitro chemosensitivity. The P-gp expression was evaluated by immunohistochemical method using JSB-1 monoclonal antibody and the results were visualized by peroxidase-antiperoxidase goat antimouse antibody and the in vitro chemosensitivity was measured by the semiautomated MTT colourimetric assay method. Depending upon the percent cells expressing P-gp and the intensity of P-gp staining, the samples were graded as absent, mild or strong for the relative P-gp expression, which was further correlated with the in vitro chemosensitivity and the clinical response of the tumors. Expression of P-gp was seen in 17 of the 30 de novo AML cases and all four relapse cases. Patients with no P-gp expression showed in vitro chemosensitivity while those with strong P-gp expression were resistant in vitro. Patients with mild P-gp expression showed varied chemosensitivity. P-gp expression correlated with clinical response to chemotherapy. Seven out of 11 patients with no P-gp achieved complete remission (C.R.). The other four died early in induction. Of five patients who expressed strong P-gp, four had resistant disease and the autopsy study of the remaining patient who died in induction revealed persistent disease. Of the 10 de novo AML patients who had mild P-gp expression, five achieved C.R. while one had resistant disease and four died in induction. All the four relapsed AML showed mild P-gp expression.(ABSTRACT TRUNCATED AT 250 WORDS)

Potentiation of Adriamycin Cytotoxicity in P388 Murine Leukemia Sensitive and Resistant to Adriamycin by use of Lonidamine and Hyperthermia

The in vitro effect of adriamycin (ADR) and lonidamine alone and in combination, at 37 °C and 43 °C, was investigated on murine leukemia P388 sensitive (P388/S) and resistant (P388/ADR) to adriamycin. The sensitive and the resistant cells were exposed in vitro with and without the drugs for 1 h at 37 °C and 43 °C. These cells were inoculated ip (106 cells/mouse) into groups of BDF, mice. Cytotoxic effect of the treatment was assessed on the basis of percentage increase in life span (% ILS) of these animals, compared to the animals receiving cells which did not receive any treatment but exposed only to 37 °C for 1 h. It was observed that exposure of P388/ADR cells to lonidamine or adriamycin alone at 43 °C for 1 h resulted in greater cell kill, thus enhancing the % ILS of the experimental animals receiving those cells, compared to that of mice receiving the cells exposed to the same drugs for 1 h at 37 °C. However, the combination of lonidamine (0.02 mM) and adriamycin (10 μg/ml) at 43 °C for 1 h showed more than a synergistic effect, resulting in a % ILS of 120. Similar results were seen in the case of P388/S; however, the observations pertaining to P388/ADR are encouraging, since the mode of treatment has reversed the acquired resistance of P388 leukemia cells to adriamycin.

Preoperative angioembolisation for life-threatening haemorrhage from Wilms' tumour: a case report

Wilms' tumour is one of the most common abdominal tumours of childhood. Severe perirenal bleeding resulting in consumptive coagulopathy and colonic obstruction are rare complications of Wilms' tumour. We present a case report of one patient with these two complications, their successful management with preoperative angioembolisation and emergency nephrectomy, and a review of the relevant literature.

Evaluation of quinidine effect on the antitumor activity of adriamycin and mitoxantrone in adriamycin-sensitive and -resistant P388 leukemia cells

Utilizing the P388 murine leukemia cells sensitive (P388/S) and resistant (P388/ADR) to Adriamycin (ADR), we evaluated the effect of quinidine, an anti-arrhythmic agent, on the cytotoxic activity of ADR and Mitoxantrone (MITO), both in vitro as well as in vivo. Quinidine enhanced the cytotoxicity of both ADR and MITO in P388/S and P388/ADR cells, as assessed by the decrease in color intensity of formazan crystal in the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. A dose dependent inhibition of 3H-thymidine and 3H-uridine incorporation was observed when the P388/S and P388/ADR cells were exposed to quinidine alone. A non-toxic concentration of quinidine (5 microM) enhanced the DNA biosynthesis inhibition induced by ADR (55 to 65%) and MITO (37 to 44%) in P388/ADR cells, indicating reversal of resistance, while in P388/S cells only a minimal increase in DNA biosynthesis inhibition was observed. The combination of quinidine at doses of 50 to 100 mg/kg significantly potentiated the antitumor activity of ADR and MITO in P388/ADR bearing mice, whereas the potentiation of ADR and MITO antitumor response was lower in P388/S bearing mice. Quinidine increased the cellular levels of ADR by 53 to 126% in P388/ADR cells in vitro, but failed to indicate such elevated levels of cellular ADR in P388/S cells. This enhanced intracellular accumulation of ADR in P388/ADR cells, explains the therapeutic efficacy of ADR and MITO in P388/ADR, both in vitro as well as in vivo. Results suggest the efficacy of quinidine to ameliorate the antitumor effects of ADR and MITO in drug resistant tumor cells.

Tween-80 Alters Natural Resistance of Sarcoma-180 to Bouvardin (NSC 259968)

Sarcoma-180 tumour (S-180) exhibits natural resistance to bouvardin (NSC 259968), a protein synthesis inhibitor that also inhibits RNA and DNA synthesis when administered over a range of non-toxic doses using 0.9 % NaCl as a vehicle. However, using Tween-80 as a vehicle, there is a substantial enhancement of cytotoxicity and a subsequent increase in the life span of animals bearing the S-180 tumour. This observation was substantiated in vitro by exposing S-180 cells to 10−6 M bouvardin in the presence and absence of Tween-80. Bouvardin, 10−6 M, in the absence of Tween-80, inhibited the incorporation of [3H]uridine by 46 %, whereas the presence of Tween-80 resulted in a 66 % inhibition of uridine incorporation.

Leptin in pituitary adenomas--a novel paracrine regulatory system

A growing number of physiological and pathophysiological processes have been shown to be influenced by leptin apart from its first recognised role as a modulator of hypothalamic appetite and weight control centers. We investigated the presence and pattern of distribution of leptin mRNA and the mRNA of the long isoform of the leptin receptor in the normal pituitary and in different types of pituitary adenomas. We also studied leptin secretion from human pituitary tumors in culture, and the in vitro pituitary hormone release following stimulation with human leptin. Leptin mRNA expression was detected at a low level of expression in 50% of tumors but in none of the normal pituitaries. By immunohistochemistry, leptin was present in occasional scattered cells in the normal pituitary and in pituitary tumors. The leptin receptor long isoform was detected in the majority (65%) of pituitary tumors and in all normal pituitaries. It did not segregate with any particular tumor type, and varying levels of expression were detected between the tissues studied. 34% of pituitary adenomas showed leptin release into the incubation media during in vitro culture. Leptin mRNA, the mRNA of the long isoform of the receptor, or in vitro leptin release, did not correlate with tumor type or with any of the other pituitary hormones released. In vitro leptin stimulation of pituitary tumors caused stimulation of FSH and a-subunit secretion from a non-functioning adenoma and TSH secretion from a somatotroph adenoma. As the co-localisation of ACTH and leptin in corticotroph cells was previously suggested, we investigated whether in vivo ACTH release is accompanied by a simultaneous plasma leptin level rise (i) in peripheral plasma samples after food intake-induced ACTH rise in healthy obese and nonobese individuals and (ii) in petrosal sinus samples after CRH injection in Cushing's disease patients. Our data suggest that a rise in ACTH levels is not accompanied by detectable rise in leptin levels in peripheral and in petrosal sinus blood samples. In summary, leptin is synthesized and stored within the pituitary and may modulate other pituitary hormone secretion, although probably it does not contribute to plasma leptin level changes. Pituitary leptin may therefore be a novel paracrine regulator of pituitary function.

In vitro effects of pentoxifylline and doxorubicin on cell survival and DNA damage in sensitive and MDR-P388 leukemia cells

The utility of chemosensitizers to improve efficacy of chemotherapy is now gaining importance. This report investigated whether an active hemorheological agent, pentoxifylline (PTX), can circumvent drug resistance in parental (P388/S) and multidrug resistant (P388/DOX) P388 leukemia cells. For detection of doxorubicin (DOX) resistance and reversal of this resistance by PTX, the incorporation of nucleic acid precursor was measured after addition of DOX and PTX, respectively. The effect of PTX on the induction of DNA strand breaks by DOX was also examined. Increased fragmentation of DNA was illustrated in P388/DOX leukemia cells exposed to the combination of DOX and PTX. The most prominent feature of the multidrug-resistant cell is the reduced accumulation of the drug intracellularly. P388/DOX cells showed less accumulation of DOX in the cell as compared to that of the parental cell line. Further studies demonstrated that PTX significantly enhanced the intracellular accumulation of DOX in both the cell lines. These studies warrant the use of PTX as an adjuvant in cancer chemotherapy.

Differential Effect of Clofibrate on Adriamycin Cytotoxicity in P388 Murine Leukemia Cells Sensitive and Resistant to Adriamycin

Clofibrate (CPIB), an antihyperlipidemic agent, was utilized as a drug response modulator to modify the cytotoxicity of adriamycin (ADR) in vitro in P388 murine lymphocytic leukemia cells sensitive (P388/S) and resistant (P388/ADR) to ADR. CPIB elicited concentration and time dependent DNA biosynthesis inhibition which was completely reversible up to the concentration of 0.0025 % in P388/S. However, only a partial reversibility of DNA biosynthesis inhibition was observed in P388/ADR cells treated with 0.0025 % of CPIB. In both P388/S and P388/ADR there was complete and irreversible DNA biosynthesis inhibition at CPIB concentration of 0.005%. These findings were further confirmed by tumorigenicity anaysis. CPIB was ineffective in altering ADR cytotoxicity in P388/S ceils. However, in P388/ADR, CPIB enhanced ADR cytotoxicity at the lower concentrations of ADR and decreased the cytotoxicity upon increase in ADR concentrations. The enhancement in ADR cytotoxicity by CPIB in P388/ADR was due to increased ADR accumulation which was absent in P388/S cells. The present findings suggest the utility of CPIB as a selective agent to circumvent ADR resistance and to reduce host toxicity due to the drug.

Selenium (Se) cytotoxicity in drug sensitive and drug resistant murine tumour

Selenium is known to inhibit growth rate of neoplastic cells. We have investigated the role of selenium (Se) in resensitization of the adriamycin (ADR) resistant murine P388/ADR cells to the action of ADR. The experiments were performed in the ADR sensitive parental P388 murine leukemia (P388/S) and its subline P388/ADR, resistant to ADR, developed in our laboratory. The effect of Se was observed to be dose dependent i.e. Se at a concentration of 5 x 10(-8)M resulted in potentiation of DNA biosynthesis whereas 5 x 10(-6)M and 5 x 10(-5)M Se resulted in inhibition of DNA-biosynthesis in P388/S cells. Along with ADR there was a further increase in inhibition of DNA biosynthesis. In P388/ADR cells, Se at 5 x 10(-6)M and 5 x 10(-8)M concentration resulted in inhibition of DNA biosynthesis, which increased further when combined with ADR indicating resensitization of these cells to the action of ADR. The inhibition was observed to be partially irreversible. These results were further confirmed in the in vivo and in vitro bioassays where the Se and Se+ ADR treatments resulted in increased lifespan of tumor bearing mice.

Pegargiminase Plus First-Line Chemotherapy in Patients With Nonepithelioid Pleural Mesothelioma: The ATOMIC-Meso Randomized Clinical Trial

Importance

Arginine deprivation using ADI-PEG20 (pegargiminase) combined with chemotherapy is untested in a randomized study among patients with cancer. ATOMIC-Meso (ADI-PEG20 Targeting of Malignancies Induces Cytotoxicity-Mesothelioma) is a pivotal trial comparing standard first-line chemotherapy plus pegargiminase or placebo in patients with nonepithelioid pleural mesothelioma.

Objective

To determine the effect of pegargiminase-based chemotherapy on survival in nonepithelioid pleural mesothelioma, an arginine-auxotrophic tumor.

Design, Setting, and Participants

This was a phase 2-3, double-blind randomized clinical trial conducted at 43 centers in 5 countries that included patients with chemotherapy-naive nonepithelioid pleural mesothelioma from August 1, 2017, to August 15, 2021, with at least 12 months' follow-up. Final follow-up was on August 15, 2022. Data analysis was performed from March 2018 to June 2023.

Intervention

Patients were randomly assigned (1:1) to receive weekly intramuscular pegargiminase (36.8 mg/m2) or placebo. All patients received intravenous pemetrexed (500 mg/m2) and platinum (75-mg/m2 cisplatin or carboplatin area under the curve 5) chemotherapy every 3 weeks up to 6 cycles. Pegargiminase or placebo was continued until progression, toxicity, or 24 months.

Main Outcomes and Measures

The primary end point was overall survival, and secondary end points were progression-free survival and safety. Response rate by blinded independent central review was assessed in the phase 2 portion only.

Results

Among 249 randomized patients (mean [SD] age, 69.5 [7.9] years; 43 female individuals [17.3%] and 206 male individuals [82.7%]), all were included in the analysis. The median overall survival was 9.3 months (95% CI, 7.9-11.8 months) with pegargiminase-chemotherapy as compared with 7.7 months (95% CI, 6.1-9.5 months) with placebo-chemotherapy (hazard ratio [HR] for death, 0.71; 95% CI, 0.55-0.93; P = .02). The median progression-free survival was 6.2 months (95% CI, 5.8-7.4 months) with pegargiminase-chemotherapy as compared with 5.6 months (95% CI, 4.1-5.9 months) with placebo-chemotherapy (HR, 0.65; 95% CI, 0.46-0.90; P = .02). Grade 3 to 4 adverse events with pegargiminase occurred in 36 patients (28.8%) and with placebo in 21 patients (16.9%); drug hypersensitivity and skin reactions occurred in the experimental arm in 3 patients (2.4%) and 2 patients (1.6%), respectively, and none in the placebo arm. Rates of poststudy treatments were comparable in both arms (57 patients [45.6%] with pegargiminase vs 58 patients [46.8%] with placebo).

Conclusions and Relevance

In this randomized clinical trial of arginine depletion with pegargiminase plus chemotherapy, survival was extended beyond standard chemotherapy with a favorable safety profile in patients with nonepithelioid pleural mesothelioma. Pegargiminase-based chemotherapy as a novel antimetabolite strategy for mesothelioma validates wider clinical testing in oncology.

Trial Registration

ClinicalTrials.gov Identifier: NCT02709512.

Hypothyroldism in a neonate following excision of a cervical teratoma

Hypothyroidism developed in a neonate following the excision of a large cervical teratoma. This finding supports the observation that cervical teratomas commonly arise from thyroid tissue. Thyroid function tests should be performed routinely in all patients in whom identifiable residual thyroid tissue is not demonstrated at the conclusion of the operation.

Amelioration of doxorubicin resistance by pentoxifylline in human chronic myeloid leukemia cells in vitro

Doxorubicin (DOX) is a potent anticancer agent, the use of which is limited by its cumulative dose-dependent cardiotoxicity. Pentoxifylline (PTX) is a non-toxic methylxanthine used clinically for the treatment of intermittent claudication. It is an active haemorheological agent, used for the treatment of defective microcirculation. In the present study, we employed PTX as a drug response modulator in combination with DOX to achieve increased cytotoxicity in human chronic myeloid leukemia (CML) cells. Inhibition of 3H-TdR incorporation was used as a measure of cytotoxicity. PTX at 100 microM concentration significantly (P less than 0.001) potentiated DOX-mediated DNA biosynthesis inhibition in CML cells in vitro. Significant synergistic inhibition was seen in 13 out of 22 CML samples. Decreased DOX accumulation is a characteristic feature of DOX resistant tumor cell lines. Drug accumulation studies demonstrated that PTX significantly (P less than 0.02) increased the intracellular accumulation of DOX in the CML cells. The enhanced DOX accumulation can be a mechanism of increased cytotoxicity by DOX-PTX combination.

Inhibition of Macromolecular Synthesis in P388 Mouse Leukemia Ascites Cells by Bouvardin (NSC 259968)

Bouvardin, a new antineoplastic plant product, inhibits macromolecular synthesis in P388 cells in a dose-dependent manner. At the same concentration of bouvardin, protein synthesis was inhibited to a greater extent than the synthesis of DNA and RNA. There was a reversal of inhibition of both DNA and RNA synthesis after the cells were washed free of bouvardin. However, there was partial reversal of inhibition of protein synthesis when the cells were washed free of the drug.

Sensitization of Chronic Myeloid Leukemia Cells to Adriamycin Cytotoxicity by Clofibrate

Clofibrate (CPIB), an antihyperlipidemic agent, was employed as a drug response modulator in this study to evaluate its action, if any, on adriamycin (ADR) cytotoxicity in adriamycin insensitive chronic myeloid leukemia (CML) cells in vitro. Inhibition of (3H)-thymidine incorporation was used as a measure of DNA biosynthesis inhibition. A marginally toxic concentration of CPIB [0.001 % (v/v)] was utilized to evaluate the cytotoxicity in CML cells exposed to ADR 5 and 10 μg/ml. A heterogeneous response was observed in 16 different CML blood samples, 9 samples displaying a synergistic, 3 an additive and 4 a less than additive inhibition of DNA biosynthesis when exposed to the combination of ADR and CPIB. The cytotoxic effect induced by ADR alone and in combination with CPIB was found to be irreversible. The data suggest that the cell membrane modulating drug CPIB is effective as an adjuvant to enhance the antiproliferative action of ADR.