Fertility Potential and Gonadal Function in Survivors of Reduced-Intensity Hematopoietic Stem Cell Transplantation

The use of reduced-intensity conditioning (RIC) regimens has increased in an effort to minimize hematopoietic stem cell transplantation (HCT) end-organ toxicity, including gonadal toxicity. We aimed to describe the incidence of fertility potential and gonadal function impairment in adolescent and young adult survivors of HCT and to identify risk factors (including conditioning intensity) for impairment. We performed a multi-institutional, international retrospective cohort study of patients age 10 to 40 years who underwent first allogeneic HCT before December 1, 2019, and who were alive, in remission, and available for follow-up at 1 to 2 years post-HCT. For females, an AMH level of ≥.5 ng/mL defined preserved fertility potential; an AMH level of ≥.03 ng/mL was considered detectable. Gonadal failure was defined for females as an elevated follicle-stimulating hormone (FSH) level >30 mIU/mL with an estradiol (E2) level <17 pg/mL or current use of hormone replacement therapy (regardless of specific indication or intent). For males, gonadal failure was defined as an FSH level >10.4 mIU/mL or current use of hormone replacement therapy. A total of 326 patients (147 females) were available for analysis from 17 programs (13 pediatric, 4 adult). At 1 to 2 years post-HCT, 114 females (77.6%) had available FSH and E2 levels and 71 (48.3%) had available AMH levels. FSH levels were reported for 125 males (69.8%). Nearly all female HCT recipients had very low levels of AMH. One of 45 (2.2%) recipients of myeloablative conditioning (MAC) and four of 26 (15.4%) recipients of reduced-intensity conditioning (RIC) (P = .06) had an AMH ≥.5 ng/m, and 8 of 45 MAC recipients (17.8%) and 12 of 26 RIC recipients (46.2%) (P = .015) had a detectable AMH level. Total body irradiation (TBI) dose and cyclophosphamide equivalent dose (CED) were not associated with detectable AMH. The incidence of female gonadal hormone failure was 55.3%. In univariate analysis, older age at HCT was associated with greater likelihood of gonadal failure (median age, 17.6 versus 13.9; P < .0001), whereas conditioning intensity (RIC versus MAC), TBI, chronic graft-versus-host disease requiring systemic therapy, and CED were not significantly associated with gonadal function. In multivariable analysis, age remained statistically significant (odds ratio [OR]. 1.11; 95% confidence interval [CI], 1.03 to 1.22) for each year increase; P = .012), Forty-four percent of the males had gonadal failure. In univariate analysis, older age (median, 16.2 years versus 14.4 years; P = .0005) and TBI dose (P = .002) were both associated with gonadal failure, whereas conditioning intensity (RIC versus MAC; P = .06) and CED (P = .07) were not statistically significant. In multivariable analysis, age (OR, 1.16; 95% CI, 1.06-1.27 for each year increase; P = .0016) and TBI ≥600 cGy (OR, 6.23; 95% CI, 2.21 to 19.15; P = .0008) remained significantly associated with gonadal failure. Our data indicate that RIC does not significantly mitigate the risk for gonadal failure in females or males. Age at HCT and (specifically in males) TBI use seem to be independent predictors of post-transplantation gonadal function and fertility status. All patients should receive pre-HCT infertility counseling and be offered appropriate fertility preservation options and be screened post-HCT for gonadal failure.

Sexual and Reproductive Health Care after Gonadotoxic Treatment in Females at a Tertiary Pediatric Hospital

STUDY OBJECTIVES

Recommendations from the Children's Oncology Group Long-Term Follow-Up (COG-LTFU) Guidelines for Survivors of Childhood, Adolescent, and Young Adult Cancer emphasize the importance of reproductive health care, yet little is known regarding adherence to these recommendations and non-fertility-related sexual and reproductive health (SRH) outcomes.

METHODS

Follow-up of outcomes on the basis of the COG-LTFU guidelines was assessed in female patients who underwent fertility preservation consultation before gonadotoxic therapy between 2016 and 2022 at a single institution and were at least 6 months from treatment completion.

RESULTS

We included 140 patients, with a mean time of 2.7 years from treatment completion. Eighty-six patients were 12 years old or older, of whom sexual activity was recorded in 59 (68.7%), and 12 of 31 (38.7%) sexually active patients underwent sexual function assessment. The 57 (66.3%) patients at high risk of premature ovarian insufficiency (POI) at diagnosis were more likely than minimal-risk counterparts (29, 33.7%) to have abnormal uterine bleeding (42.1% vs 17.2%, P = .03), to be diagnosed with POI (29.8% vs 0%, P = .01), and to have sexual activity recorded (77.2% vs 51.7%, P = .03). Of 17 patients with POI, 82.4% were on hormone replacement therapy, and 58.8% had undergone bone mineral density testing.

CONCLUSION

This study adds to the limited literature regarding non-fertility-related SRH outcomes after gonadotoxic therapy and illustrates opportunities to improve adherence to the COG-LTFU guidelines. Increased attention to SRH guidelines may increase detection and treatment of SRH conditions, improving the health and quality of life of female cancer survivors.

The impact of hiring a full-time fertility navigator on fertility-related care and fertility preservation at a pediatric institution

Fertility navigators (FNs) are important in communicating infertility risk and fertility preservation (FP) options to patients receiving gonadotoxic therapies. This retrospective study examined electronic medical records of patients with fertility consults at a large pediatric institution (2017-2019), before and after hiring a full-time FN. Of 738 patient encounters, 173 consults were performed pre-navigator and 565 post-navigator. Fertility consults for long-term follow-up cancer survivors increased most substantially: pre-navigator (n = 7) and post-navigator (n = 387). Across diagnoses, females had a larger increase in consults compared to males (χ² [3, N = 738] = 8.17, p < .05). Findings highlight FNs' impact on counseling rates, particularly in survivorship.

A synopsis of global frontiers in fertility preservation

Since 2007, the Oncofertility Consortium Annual Conference has brought together a diverse network of individuals from a wide range of backgrounds and professional levels to disseminate emerging basic and clinical research findings in fertility preservation. This network also developed enduring educational materials to accelerate the pace and quality of field-wide scientific communication. Between 2007 and 2019, the Oncofertility Consortium Annual Conference was held as an in-person event in Chicago, IL. The conference attracted approximately 250 attendees each year representing 20 countries around the world. In 2020, however, the COVID-19 pandemic disrupted this paradigm and precluded an in-person meeting. Nevertheless, there remained an undeniable demand for the oncofertility community to convene. To maintain the momentum of the field, the Oncofertility Consortium hosted a day-long virtual meeting on March 5, 2021, with the theme of "Oncofertility Around the Globe" to highlight the diversity of clinical care and translational research that is ongoing around the world in this discipline. This virtual meeting was hosted using the vFairs ® conference platform and allowed over 700 people to participate, many of whom were first-time conference attendees. The agenda featured concurrent sessions from presenters in six continents which provided attendees a complete overview of the field and furthered our mission to create a global community of oncofertility practice. This paper provides a synopsis of talks delivered at this event and highlights the new advances and frontiers in the fields of oncofertility and fertility preservation around the globe from clinical practice and patient-centered efforts to translational research.

Parent-Adolescent Concordance Regarding Fertility Perspectives and Sperm Banking Attempts in Adolescent Males With Cancer

OBJECTIVE

Approximately half of male childhood cancer survivors experience impaired fertility, yet fertility preservation (FP) remains underutilized. Although parent recommendation influences adolescents' decision-making, parents may be uncertain and/or underrate their sons' parenthood goals. This study assessed parent-adolescent and family-level concordance regarding adolescent fertility perspectives (i.e., values, goals) and associations with FP attempts.

METHODS

A prospective pilot study examined the impact of a family-centered values clarification tool (FAST) on banking attempts among adolescent males newly diagnosed with cancer at risk for infertility. The FAST assessed adolescent and parent perceptions of adolescents' fertility values and goals (i.e., perceived threat of infertility, perceived benefits/barriers to banking). Parent-adolescent concordance and family-level concordance on fertility perspectives were examined, along with associations with banking attempts and salient demographic factors.

RESULTS

Ninety-eight participants (32 adolescents aged 12-20, 37 mothers, 29 fathers) from 32 families completed the FAST before treatment initiation. Parent-adolescent dyads were concordant on approximately one-half of responses. Banking attempts were associated with higher family-level concordance regarding perceived benefits, r(32) = .40, p = .02. Older adolescent age was associated with higher family-level concordance regarding perceived threat, r(31) = .37, p = .04, and benefits, r(32) = .40, p = .03. Fathers' education was associated with higher family-level concordance regarding barriers, r(21) = .53, p = .01.

CONCLUSIONS

When parents were concordant with their son's fertility values and goals, particularly perceived benefits, adolescents were more likely to attempt FP. Clinicians should facilitate sharing of fertility perspectives within families before cancer treatment, especially with younger adolescents. Psychosocial support for families facing FP decisions is recommended at diagnosis and across the care continuum.

A View from the past into our collective future: the oncofertility consortium vision statement

Purpose

Today, male and female adult and pediatric cancer patients, individuals transitioning between gender identities, and other individuals facing health extending but fertility limiting treatments can look forward to a fertile future. This is, in part, due to the work of members associated with the Oncofertility Consortium.

Methods

The Oncofertility Consortium is an international, interdisciplinary initiative originally designed to explore the urgent unmet need associated with the reproductive future of cancer survivors. As the strategies for fertility management were invented, developed or applied, the individuals for who the program offered hope, similarly expanded. As a community of practice, Consortium participants share information in an open and rapid manner to addresses the complex health care and quality-of-life issues of cancer, transgender and other patients. To ensure that the organization remains contemporary to the needs of the community, the field designed a fully inclusive mechanism for strategic planning and here present the findings of this process.

Results

This interprofessional network of medical specialists, scientists, and scholars in the law, medical ethics, religious studies and other disciplines associated with human interventions, explore the relationships between health, disease, survivorship, treatment, gender and reproductive longevity.

Conclusion

The goals are to continually integrate the best science in the service of the needs of patients and build a community of care that is ready for the challenges of the field in the future.

2019 Pediatric Initiative Network: Progress, Proceedings, and Plans

Impairment of fertility and sexual/reproductive health are common after oncologic therapy, and are known to have negative impacts on romantic relationships and psychosocial well-being among childhood cancer survivors. The Pediatric Initiative Network (PIN) is an international, multidisciplinary group of providers within the Oncofertility Consortium dedicated to preserving and protecting the fertility of children and adolescents at risk for infertility due to medical conditions or treatments. The PIN and its Best Practices and Research committees meet virtually throughout the year, with one annual in-person meeting. The purpose of this "proceedings" is to highlight key discussion points from the annual PIN meeting which took place on November 11, 2019, to 1) provide a context for pediatric groups across the country on what oncofertility programs are currently doing and why, and 2) inform stakeholders of past, present and future initiatives that may be of value to them and the patient populations they serve.

Perceptions of participating in family-centered fertility research among adolescent and young adult males newly diagnosed with cancer: A qualitative study

BACKGROUND

Over half of male childhood cancer survivors experience infertility after treatment, which is known to cause distress and impact future quality of life. Sperm banking rates remain low, and little is known about how adolescent and young adult (AYA) males and their families make fertility preservation (FP) decisions. This study examined AYA and parent perceptions of participating in a research study focused on testing a new FP decision tool at the time of cancer diagnosis.

METHODS

Forty-four participants (19 mothers, 11 fathers, 14 male AYAs 12-25 years old) from 20 families completed brief assessments at diagnosis and approximately one month later, including a qualitative interview exploring the impact of study participation. Verbatim transcripts were coded through thematic content analysis using the constant comparison method.

RESULTS

Two major themes emerged: (1) a positive effect of participating in the study and (2) a neutral effect (no positive/negative effect of participation). Subthemes that emerged for participants who noted a positive effect included (a) participation prompted deeper thinking, (b) participation influenced family conversations, and (c) participation resulted in altruism/helping others. No participant reported a negative effect.

CONCLUSIONS

This study demonstrates that participation in family-centered research focused on FP among AYA males, before treatment begins, is perceived as beneficial or neutral at the time of a new cancer diagnosis. These findings provide support for future family-centered FP interventions for this population.

Conducting reproductive research during a new childhood cancer diagnosis: ethical considerations and impact on participants

PURPOSE

Research among adults shows benefits and low perceived burden of engaging in behavioral research. However, questions remain regarding the ethics of conducting behavioral research in pediatric populations during sensitive situations, including during a new life-threatening diagnosis or at end-of-life. We examined reactions to participating in a behavioral reproductive research study among male adolescents newly diagnosed with cancer and their parents, as a step towards optimizing fertility preservation utilization in a population where future infertility is common.

METHODS

Pediatric literature regarding the ethics of behavioral research was reviewed. In our pilot, forty-four participants (19 mothers, 11 fathers, 14 male adolescents newly diagnosed with cancer) from 20 families completed demographic questionnaires and a fertility preservation decision tool developed by the study team. Qualitative interviews exploring the impact of study participation were subsequently conducted. Verbatim transcripts were coded for thematic content using the constant comparison method.

RESULTS

Literature review showed positive reactions to research participation among youth/caregivers. In our pilot study, 89% (n = 17) of mothers, 64% (n = 7) of fathers, and 71% (n = 10) of adolescents reported at least one benefit of participating. Eleven percent (n = 2) of mothers, 36% (n = 4) of fathers, and 29% (n = 4) of adolescents said they were not affected; none of the participants reported a negative effect.

CONCLUSION

Consistent with prior literature, our study suggests behavioral reproductive research prior to cancer treatment can offer direct benefits to participants and society, without increasing burden. These findings will inform future interventions to improve long-term psychosocial and reproductive outcomes for youth with cancer.

Examining predictors and outcomes of fertility consults among children, adolescents, and young adults with cancer

Infertility has a negative impact on quality of life among cancer survivors. Studies show establishing a fertility team results in improved patient satisfaction. A review of electronic medical records was performed to examine predictors of fertility referrals, interventions, and the impact of an opt-out consult mechanism. Findings show many patients, particularly those that are younger, are still not receiving fertility counseling despite the presence of a fertility team. Notably, patients were 3.6 times more likely to receive a consult after the opt-out. Strategies are needed to improve access to fertility related care, particularly in groups where consults are underutilized.

Accuracy of preoperative CT T staging of renal cell carcinoma: which features predict advanced stage?

AIMS

To characterise CT findings in renal cell carcinoma (RCC), and establish which features are associated with higher clinical T stage disease, and to evaluate patterns of discrepancy between radiological and pathological staging of RCC.

MATERIALS AND METHODS

Preoperative CT studies of 92 patients with 94 pathologically proven RCCs were retrospectively reviewed. CT stage was compared with pathological stage using the American Joint Committee on Cancer (AJCC), 7(th) edition (2010). The presence or absence of tumour necrosis, perinephric fat standing, thickening of Gerota's fascia, collateral vessels were noted, and correlated with pT stage. The sensitivity, specificity, and positive (PPV) and negative predictive values (NPV) for predicting pT stage ≥pT3a were derived separately for different predictors using cross-tabulations.

RESULTS

Twenty-four lesions were pathological stage T1a, 21 were T1b, seven were T2a, 25 were T3a, 11 were T3b, four were T3c, and two were T4. There were no stage T2b. Sixty-three (67%) patients had necrosis, 27 (29%) thickening of Gerota's fascia (1 T1a), 25 had collateral vessels (0 T1a), 28 (30%) had fat stranding of <2 mm, 20 (21%) of 2-5mm and one (1%) of >5 mm. For pT stage ≥pT3a, the presence of perinephric fat stranding had a sensitivity, specificity, PPV and NPV of 74%, 65%, 63%, and 76%, respectively. Presence of tumour necrosis had a sensitivity, specificity, PPV, and NPV of 81%, 44%, 54%, and 72%, respectively. Thickening of Gerota's fascia had a sensitivity, specificity, PPV, and NPV of 52%, 90%, 81% and 70%, respectively; and enlarged collateral vessels had a sensitivity, specificity, PPV, and NPV value of 52%, 94%, 88%, and 71% respectively.

CONCLUSION

The presence of perinephric stranding and tumour necrosis were not reliable signs for pT stage >T3a. Thickening of Gerota's fascia and the presence of collateral vessels in the peri- or paranephric fat had 90% and 94% specificity, with 82% and 88% PPV, respectively, for the presence of tumour stage for pT stage >T3a. These are considered reliable signs of locally advanced renal cancer.

Impact of full-field digital mammography on pre-operative diagnosis and surgical treatment of mammographic microcalcification

Accurate pre-operative diagnosis of impalpable breast lesions correlates closely with the number of surgical procedures required for treatment. Correct diagnosis of mammographic microcalcification (MM) as ductal carcinoma in situ (DCIS) or invasive breast cancer is important because lesions upgraded to malignant diagnosis at surgery require repeat surgical procedures in 44 % of cases. Despite correct pre-operative diagnosis of MM, 26 % require second therapeutic operations to achieve surgical clearance. Theoretically, improved conspicuity of malignant MM using digital mammography could improve diagnostic work-up and improve surgical outcomes for MM. To determine the impact of full-field digital mammography (FFDM) on the diagnostic accuracy and positive predictive value (PPV) of biopsy of MM and surgical management of MM, screening and symptomatic cases with MM (n = 1,479) were reviewed for women imaged between August 2007 and March 2010 using screen-film mammography (SFM) (n = 711), and using FFDM, imaged between April 2010 to March 2012 (n = 768). Demographic information including pre and postoperative diagnosis, and number and types of surgical procedures were recorded. Overall, 302 (128 invasive) and 251 (110 invasive) malignant lesions were diagnosed using SFM and FFDM, respectively. Reduction in PPV of biopsy was observed (SFM 42.5 %; FFDM 32.7 %, p < 0.001). Correct pre-operative diagnosis was achieved at first attempt more often with FFDM (SFM 80.6 %; FFDM 89.5 %, p < 0.001). For lesions with pre-operative diagnosis, B5 more cases achieved surgical clearance with a single therapeutic operation with FFDM (SFM 66.3 %; FFDM 76.7 %, p = 0.017), and more lesions over 2 cm underwent mastectomy as the initial surgical procedure (SFM 47.0 %; FFDM 62.9 %, p = 0.005). Correct pre-operative diagnosis of MM using digital mammography reduced second therapeutic operations but increased mastectomy rate in larger cancers over two centimetres. This will increase concerns about treatment of lesions detected in the screening programme with widespread use of digital mammography.

Isolation of Aspergillus species from the airway of lung transplant recipients is associated with excess mortality

BACKGROUND

Aspergillus spp. are the leading cause of invasive fungal infection in lung transplant recipients. We investigated the relationship between the isolation of Aspergillus spp. from the respiratory tract of lung transplant recipients and their risk of mortality.

METHODS

A retrospective, observational cohort study of all patients who received lung allografts between January 1999 and May 2011 at a single UK centre was performed. The time from transplantation to death was analysed using Cox regression models. Isolation of Aspergillus spp. from the respiratory tract was included as a covariate in the Cox regression model.

RESULTS

Two hundred-thirteen patients were included. The median follow-up time was 5 years during which 102 patients (47.9%) died. Aspergillus was isolated from 74 (34.7%) patients. Twenty patients (27%) had Aspergillus isolated in the first 60 days post-transplant. Forty-one patients (55.4%) in the Aspergillus group and 61 patients (43.9%) in the non-Aspergillus group died during follow-up. A hazard ratio of 2.2 (95% CI 1.5-3.3; P < 0.001) for death following a positive Aspergillus sample was observed.

CONCLUSION

Isolation of Aspergillus spp. from patients following lung transplantation is associated with a significant increase in mortality. Novel preventative strategies are required to minimise the impact of Aspergillus in lung transplant recipients.

Is thought-action fusion specific to obsessive-compulsive disorder?: a mediating role of negative affect

Thought-action fusion (TAF) is a cognitive bias presumed to underlie the development of obsessional problems (i.e. obsessive-compulsive disorder; OCD). Previous studies have found that TAF is related to not only OCD, but also to other anxiety disorders. In the present study we compared levels of TAF in OCD patients and in patients with other anxiety disorders, depression, and healthy controls to examine whether TAF is characteristic of individuals with emotional distress in general, as opposed to anxiety disorders per se. We also examined whether negative affect (i.e. anxiety and depression) mediates the relationship between OCD and TAF. Results indicated that OCD patients were characterized by higher scores on likelihood-self and likelihood-other TAF, but that this difference was predominately due to differences in negative affect. These findings support a model in which negative affect mediates the relationship between OCD and TAF.

Thought control strategies in obsessive-compulsive disorder: a replication and extension

Previous research suggests that individuals with OCD use maladaptive strategies to control their unpleasant thoughts (Behav Res Ther (1977) 35, 775). These include worry and self-punishment strategies. In the present study we replicated and extended the previous findings by comparing thought control strategies used by patients with OCD to strategies used by anxious and non-anxious control participants. We also examined changes in thought control strategies for OCD patients who underwent cognitive-behavioral therapy. Compared to controls, OCD patients reported more frequent use of worry and punishment strategies, and less frequent use of distraction. Following successful treatment, OCD patients evidenced increased use of distraction and decreased use of punishment. Findings are discussed in terms of the cognitive model of OCD.

Raf induces NF-kappaB by membrane shuttle kinase MEKK1, a signaling pathway critical for transformation

NF-kappaB is regulated by inhibitor proteins (IkappaBs), which retain NF-kappaB in the cytoplasm. Signal-induced phosphorylation by the IkappaB-kinase complex containing the IkappaB-kinases 1 and 2 (IKK-1/2 or IKK-alpha/beta) and subsequent degradation of the IkappaB proteins are prerequisites for NF-kappaB activation. Many signals induce NF-kappaB, one of them being oncogenic Raf kinase. We investigated whether NF-kappaB induction is critical for Raf-mediated transformation. Here, we demonstrate that inhibition of NF-kappaB interferes with transformation by the Raf-oncogene, and we characterized the mechanism of NF-kappaB induction by activated Raf kinase and the tumor promoter phorbol 12-myristate 13-acetate (PMA). NF-kappaB activation by PMA and Raf critically depends on the IkappaB-kinase complex, most notably on IKK-2. A major signaling pathway induced by Raf is the mitogenic cytoplasmic kinase cascade. However, different inhibitors of this cascade do not affect PMA- and Raf-mediated NF-kappaB activation. Raf does not phosphorylate the IkappaB-kinase proteins directly. Raf rather synergizes with another membrane shuttle kinase MEKK1, and Raf-mediated activation of NF-kappaB is blocked by a dominant negative form of MEKK1. These results suggest that Raf induction of NF-kappaB is relayed by MEKK1, but not by the classical mitogenic cytoplasmic kinase cascade.

Self-reported psychopathy: a validation study

Two studies are reported examining the reliability and validity of Levenson's Self-Report Psychopathy Scale (LSRP; Levenson, Kiehl, & Fitzpatrick, 1995) in a noninstitutionalized population. The first study used 1,958 undergraduates to examine the factor structure of the LSRP and its relation to serious antisocial behavior and common dimensions of personality. The second study (n = 70) included performance tasks known to discriminate psychopathic from nonpsychopathic prisoners. Results of the studies support the reliability and validity of the LSRP. The 2-factor structure of the inventory was strongly replicated in a series of confirmatory factor analyses. Predicted relations were observed between the LSRP and other self-report instruments of delinquency. In addition, the factors of the LSRP demonstrated the predicted divergent relations to traditional personality traits. Finally, psychopathic undergraduates showed deficits in response modulation similar to those observed in incarcerated psychopaths. Implications for psychopathy in general are also discussed.

Structural motifs involved in ubiquitin-mediated processing of the NF-kappaB precursor p105: roles of the glycine-rich region and a downstream ubiquitination domain

The ubiquitin proteolytic system plays a major role in a variety of basic cellular processes. In the majority of these processes, the target proteins are completely degraded. In one exceptional case, generation of the p50 subunit of the transcriptional regulator NF-kappaB, the precursor protein p105 is processed in a limited manner: the N-terminal domain yields the p50 subunit, whereas the C-terminal domain is degraded. The identity of the mechanisms involved in this unique process have remained elusive. It has been shown that a Gly-rich region (GRR) at the C-terminal domain of p50 is an important processing signal. Here we show that the GRR does not interfere with conjugation of ubiquitin to p105 but probably does interfere with the processing of the ubiquitin-tagged precursor by the 26S proteasome. Structural analysis reveals that a short sequence containing a few Gly residues and a single essential Ala is sufficient to generate p50. Mechanistically, the presence of the GRR appears to stop further degradation of p50 and to stabilize the molecule. It appears that the localization of the GRR within p105 plays an important role in directing processing: transfer of the GRR within p105 or insertion of the GRR into homologous or heterologous proteins is not sufficient to promote processing in most cases, which is probably due to the requirement for an additional specific ubiquitination and/or recognition domain(s). Indeed, we have shown that amino acid residues 441 to 454 are important for processing. In particular, both Lys 441 and Lys 442 appear to serve as major ubiquitination targets, while residues 446 to 454 are independently important for processing and may serve as the ubiquitin ligase recognition motif.

Sequential DNA damage-independent and -dependent activation of NF-kappaB by UV

NF-kappaB activation in response to UV irradiation of HeLa cells or of primary human skin fibroblasts occurs with two overlapping kinetics but totally different mechanisms. Although both mechanisms involve induced dissociation of NF-kappaB from IkappaBalpha and degradation of IkappaBalpha, targeting for degradation and signaling are different. Early IkappaBalpha degradation at 30 min to approximately 6 h is not initiated by UV-induced DNA damage. It does not require IkappaB kinase (IKK), as shown by introduction of a dominant-negative kinase subunit, and does not depend on the presence of the phosphorylatable substrate, IkappaBalpha, carrying serines at positions 32 and 36. Induced IkappaBalpha degradation requires, however, intact N- (positions 1-36) and C-terminal (positions 277-287) sequences. IkappaB degradation and NF-kappaB activation at late time points, 15-20 h after UV irradiation, is mediated through DNA damage-induced cleavage of IL-1alpha precursor, release of IL-1alpha and autocrine/paracrine action of IL-1alpha. Late-induced IkappaBalpha requires the presence of Ser32 and Ser36. The late mechanism indicates the existence of signal transfer from photoproducts in the nucleus to the cytoplasm. The release of the 'alarmone' IL-1alpha may account for some of the systemic effects of sunlight exposure.

Ubiquitin-mediated processing of NF-kappa B transcriptional activator precursor p105. Reconstitution of a cell-free system and identification of the ubiquitin-carrier protein, E2, and a novel ubiquitin-protein ligase, E3, involved in conjugation

In most cases, the transcriptional factor NF-kappa B is a heterodimer consisting of two subunits, p50 and p65, which are encoded by two distinct genes of the Rel family. p50 is translated as a precursor of 105 kDa. The C-terminal domain of the precursor is rapidly degraded, forming the mature p50 subunit consisted of the N-terminal region of the molecule. The mechanism of generation of p50 is not known. It has been suggested that the ubiquitin-proteasome system is involved in the process; however, the specific enzymes involved and the mechanism of limited proteolysis, in which half of the molecule is spared, have been obscure. Palombella and colleagues (Palombella, V. J., Rando, O. J., Goldberg, A. L., and Maniatis, T. (1994) Cell 78, 773-785) have shown that ubiquitin is required for the processing in a cell-free system of a truncated, artificially constructed, 60-kDa precursor. They have also shown that proteasome inhibitors block the processing both in vitro and in vivo. In this study, we demonstrate reconstitution of a cell-free processing system and demonstrate directly that: (a) the ubiquitin-proteasome system is involved in processing of the intact p105 precursor, (b) conjugation of ubiquitin to the precursor is an essential intermediate step in the processing, (c) the recently discovered novel species of the ubiquitin-carrier protein, E2-F1, that is involved in the conjugation and degradation of p53, is also required for the limited processing of the p105 precursor, and (d) a novel, approximately 320-kDa species of ubiquitin-protein ligase, is involved in the process. This novel enzyme is distinct from E6-AP, the p53-conjugating ligase, and from E3 alpha, the "N-end rule" ligase.